bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of topography on coseismic displacements induced by the Friuli 1976 and the Irpinia 1980 earthquakes (Italy) analyzed through a two‐dimensional hybrid model
Authors: Armigliato Alberto , Tinti Stefano
Published: December 2003

We investigate the perturbations introduced by the local topography on the coseismic displacement components induced by crustal seismic faults. The approach, proposed by Tinti and Armigliato [2002], is applicable to homogeneous two‐dimensional domains with arbitrary topography of the free surface. It uses both analytical results, valid for homogeneous spaces and half‐spaces bounded by a flat free surface (FFS), and a numerical code solving the equations of equilibrium of linear elasticity through a finite element (FE) scheme. A major characteristic of our “hybrid” method is that it allows for the correct representation of the displacement components in correspondence with the fault, which does not need to be explicitly introduced in the FE mesh. We show that, in the case of homogeneous domains, this makes our approach preferable to pure FE schemes. Our hybrid approach is here applied to two different disastrous events of the recent Italian seismic history, for which topography is expected to play an important role, namely the 6 May 1976 (MS = 6.5) Friuli and the 23 November 1980 (MS = 6.9) Irpinia‐Basilicata earthquakes. For each event, we selected hypotheses for the parent fault proposed in the literature and compared the coseismic displacements computed through the widely used analytical models dealing with FFS and through our hybrid approach, accounting for the effect of realistic topographies. The most relevant effects are observed in the case of the Irpinia earthquake: depending on the profile chosen, the computed misfits can be as high as 19 and 13% for the horizontal and vertical displacements, respectively, with absolute differences up to 9 and 10 cm.
Significance of direct and indirect radiative forcings of aerosols in the East China Sea region
Authors: Nakajima Teruyuki , Sekiguchi Miho , Takemura Toshihiko , Uno Itsushi , Higurashi Akiko , Kim Dohyeong , Sohn Byung Ju , Oh Sung‐Nam , Nakajima Takashi Y. , Ohta Sachio , Okada Itaru , Takamura Tamio , Kawamoto Kazuaki
Published: December 2003

Radiative forcings of aerosols and clouds in the East China Sea region are studied using data from surface radiation measurements, satellite remote sensing, and model simulation conducted in April 2001 as a study of Asian Atmospheric Particle Environmental Change Studies (APEX) cooperating with International Global Atmospheric Chemistry (IGAC)/ACE‐Asia project. The monthly mean whole sky radiative forcing of the aerosol direct effect is derived from various methods as −5 to −8 W/m2 at the top of atmosphere (TOA) and −10 to −23 W/m2 at Earth's surface of Gosan (33.28N, 127.17E) and Amami‐Oshima (28.15N, 129.30E) sites, though there is a large regional difference caused by changes in the aerosol optical thickness and single scattering albedo. The cloud forcing is estimated as −20 to −40 W/m2, so that the aerosol direct forcing can be comparable to the cloud radiative forcing at surface. However, the estimate of the aerosol direct forcing thus obtained strongly depends on the estimation method of the aerosol properties, especially on the single scattering albedo, generating a method difference about 40%. The radiative forcing of the aerosol indirect effect is roughly estimated from satellite method and SPRINTARS model as −1 to −3 W/m2 at both TOA and surface.
Self‐consistent model of magnetospheric ring current and electromagnetic ion cyclotron waves: The 2–7 May 1998 storm
Authors: Khazanov G. V. , Gamayunov K. V. , Jordanova V. K.
Published: December 2003

A complete description of a self‐consistent model of magnetospheric ring current interacting with electromagnetic ion cyclotron waves is presented. The model is based on the system of two kinetic equations; one equation describes the ring current ion dynamics, and another equation describes the wave evolution. The effects on ring current ions interacting with electromagnetic ion cyclotron waves and back on waves are considered self‐consistently by solving both equations on a global magnetospheric scale under nonsteady state conditions. The developed model is employed to simulate the entire 2–7 May 1998 storm period. First, the trapped number fluxes of the ring current protons are calculated and presented along with comparison with the data measured by the three‐dimensional hot plasma instrument Polar/HYDRA. Incorporating in the model the wave‐particle interaction leads to much better agreement between the experimental data and the model results. Second, examining of the wave (MLT, L shell) distributions produced by the model during the storm progress reveals an essential intensification of the wave emission about 2 days after the main phase of the storm. This result is well consistent with the earlier ground‐based observations. Finally, the theoretical shapes and the occurrence rates of the wave power spectral densities are studied. It is found that about 2 days after the storm's main phase on 4 May, mainly non‐Gaussian shapes of power spectral densities are produced.
Structure of the outer cusp and sources of the cusp precipitation during intervals of a horizontal IMF
Authors: Němeček Z. , Šafránková J. , Přech L. , Šimunek J. , Sauvaud J.‐A. , Fedorov A. , Stenuit H. , Fuselier S. A. , Savin S. , Zelenyi L. , Berchem J.
Published: December 2003

The cusp represents a place where the magnetosheath plasma can directly penetrate into the magnetosphere. Since the main transport processes are connected with merging of the interplanetary and magnetospheric field lines, the interplanetary magnetic field (IMF) orientation plays a decisive role in the formation of the high‐altitude cusp. The importance of the sign of the IMF BZ component for this process was suggested about 40 years ago and later it was documented by many experimental investigations. However, situations when IMF BZ is the major IMF component are rather rare. The structure of the cusp during periods of a small IMF BZ has not been as widely investigated, probably due to the fully three‐dimensional nature of the interaction. The present case study reveals the importance of horizontal IMF components on the global magnetospheric configuration as well as on small‐scale processes at the cusp‐magnetosheath interface. We have used simultaneous measurements of several spacecraft (ISTP program) operating in different regions of interplanetary space and two closely spaced satellites (INTERBALL‐1/MAGION‐4) crossing the cusp‐magnetosheath boundary to show the connection between the short‐scale and large‐scale phenomena. In the Northern Hemisphere, observations suggest a presence of two spots of cusp‐like precipitation supplied by reconnection occurring simultaneously in both hemispheres. A source of this bifurcation is the positive IMF BY component further enhanced by the field draping in the magnetosheath. This magnetic field component shifts the entry point far away from the local noon but in opposite sense in either hemisphere.
Z‐mode sounding within propagation “cavities” and other inner magnetospheric regions by the RPI instrument on the IMAGE satellite
Authors: Carpenter D. L. , Bell T. F. , Inan U. S. , Benson R. F. , Sonwalkar V. S. , Reinisch B. W. , Gallagher D. L.
Published: December 2003

When the Radio Plasma Imager (RPI) on the IMAGE satellite operates in the inner plasmasphere and at moderate to low altitudes over the poles, pulses emitted at the low end of the RPI 3 kHz to 3 MHz sounding frequency range can propagate in the Z mode as well as the whistler mode. At medium altitudes within the plasmasphere, discrete Z‐mode echoes with turning points Earthward of IMAGE are often observed, analogous in form to the regular and oblique Z‐mode echoes found on topside sounder records. In the polar regions, where fpe/fce < 1 usually obtains, the Z‐mode echoes tend to be diffuse and to exhibit properties such as an intensity decrease at the local value of fce, where there is a significant change with frequency in the topology of the Z‐mode refractive index surface. At altitudes up to a few thousand km in polar or near‐polar regions, Z‐mode soundings regularly provide information on the local value of fpe, whereas passive recordings that depend upon indications of the upper hybrid resonance frequency fuh usually fail to do so. Within the transition region from the auroral zone to the plasmasphere and within the plasmasphere itself, at altitudes from ≈2000 km upward, we find evidence of the Z‐mode trapping phenomenon, noted previously in connection with natural wave emissions detected at polar latitudes. This phenomenon involves echoes returning both from turning points in denser regions Earthward of the sounder and from more tenuous regions above. Within Z‐mode “cavities,” discrete Z‐mode echoes are found to propagate back and forth along geomagnetic‐field‐aligned paths between upper and lower altitude reflection points. The echoes present unique forms, depending upon whether IMAGE is located above or below a minimum in the altitude profile of the Z‐mode cutoff frequency. Through an inversion process, such echoes make possible determination of the electron density profile along geomagnetic field lines to distances of thousands of km above the location of IMAGE, all on the basis of echo delay information within frequency bands only ≈20 to 30 kHz wide. The forms of such density profiles are in general agreement with results reported from conventional RPI X‐mode sounding from higher altitudes, as well as with predictions based upon a diffusive equilibrium model of density along plasmasphere field lines.
Decay‐rate dependence of anhysteretic remanence: Fundamental origin and paleomagnetic applications
Authors: Yu Yongjae , Dunlop David J.
Published: December 2003

We have measured the intensity of anhysteretic remanent magnetization (ARM) as a function of alternating field (AF) decay rate. For synthetic and natural single‐domain (SD) and pseudo‐single‐domain (PSD) magnetites, ARM intensity increases as decay rate decreases. Multidomain (MD) magnetites have the opposite response, ARM increasing as the decay rate increases. These are identical to the SD/PSD and MD dependences of thermoremanent magnetization on cooling rate. For all grain sizes and domain structures, ARM intensity increases as the AF decay rate used to achieve an initial demagnetized state decreases. Decay‐rate differences in ARM intensity are a property of low‐ and medium‐coercivity grains, as shown by annealing and by stepwise AF demagnetizing samples. We interpret the SD results to mean that increased AF exposure time permits a closer approach to equilibrium magnetization. An approximate thermal activation theory based on Néel [1949] and an exact theory by Egli and Lowrie [2002] predict 6–11% increases in ARM for an order of magnitude decrease in decay rate, in reasonable accord with the observed 12% increase for 0.065 μm SD grains. For MD grains, we hypothesize that increased exposure time (slower decay) permits more efficient self‐demagnetization, reducing ARM. Low‐coercivity grains experience the largest self‐demagnetizing fields and therefore have the largest decay‐rate response. Initial‐state decay‐rate response is attributed to longer exposure times leaving domain walls more strongly pinned in deeper potential wells (the net self‐demagnetizing field is zero in the demagnetized state). Acquisition decay‐rate, annealing, and initial‐state responses of PSD grains are a blend of SD and MD responses. Because ARM is the most frequently used normalizer in relative paleointensity determination, it is important either to use a standard decay rate or else to remove the decay‐rate dependence by demagnetizing the ARM to ∼30% of its initial value (ARM0.3). A standard demagnetization level for the normalizing ARM is particularly important when comparing paleointensity records from different laboratories.
A physically based model for calculating contributing area on hillslopes and along valley bottoms
Authors: Lindsay John B.
Published: December 2003

Most existing methods of calculating contributing area are unable to accurately model the pattern of contributing area on hillslopes and along valley bottoms. This paper describes a new flow algorithm, the adjustable dispersion routing algorithm (ADRA). Rather than calculating contributing area using predetermined flow characteristics that are insensitive to location in the landscape, ADRA predicts channel location and adjusts flow characteristics accordingly. ADRA increases the degree of flow divergence downslope from divides until a channel head is detected. Channel head locations are estimated on the basis of a user‐defined threshold of an area‐slope function. Therefore the algorithm overcomes the problems of aggregated flow on hillslopes and divergent flow along valley bottoms. The pattern of catchment area produced by ADRA was compared with similar patterns calculated using a similar flow algorithm for a variety of natural landscapes. ADRA produced patterns of contributing area that were more consistent with the theory of channel initiation.
Morphology of azurophil lysosomes in polymorphonuclear leukocytes from humans with rapidly progressive periodontitis
Authors: Pippin David J. , Swafford James R. , McCunniff Michael D.
Published: December 2003

Previous investigations have shown that subjects with rapidly progressive periodontitis (RPP), an early‐onset aggressive form of periodontitis, have polymorphonuclear leukocytes (PMNs) with increased intracellular levels of β‐glucuronidase, a characteristic enzyme of azurophil lysosomes. The current study attempted to account for that increase. Ten healthy controls and 10 otherwise healthy subjects with RPP participated. PMNs from peripheral blood were separated, fixed and reacted for peroxidase to identify azurophil lysosomes. Using transmission electron microscopy, 20 PMNs per subject were photographed at 10 000×. Photographs were subsequently digitized and analyzed by computer. RPP PMNs had a higher percentage of the area of the cell profile occupied by azurophil lysosomes compared to control subjects’ PMNs. The RPP subjects also had greater absolute numbers of azurophil lysosomes per cell. Lysosome shape was assessed visually. There were no differences between RPP and control groups for lysosome shape, with the majority of lysosomes in each group exhibiting a round or oval shape. RPP lysosomes did exhibit a significantly greater mean size.M
Profile of subgingival microbiota in children with primary dentition
Authors: Kamma Joanna J. , Diamanti‐Kipioti Anthoula , Nakou Mela , Mitsis Fotis J.
Published: December 2003

Eruption of primary teeth has a great influence on the oral environment by providing suitable niches for bacterial colonization. The aim of the study was to investigate the composition of the subgingival microbiota of primary incisors, canines and molars in 40 systemically healthy children aged 4–5 yr, chosen randomly. Subgingival plaque samples were taken from the mesiobuccal sites of primary incisors (61, 81), canines (53, 73) and molars (64, 84). The samples were cultured for bacterial isolation anaerobically and in 10% CO2 plus air using selective and non‐selective media. Forty‐one different microbial species were isolated. Gemella morbillorum and Peptostreptococcus magnus were statistically significantly more frequently detected in incisors while P. micros, Streptococcus intermedius, Bacteroides forsythus, Fusobacterium nucleatum, Prevotella loeschei, P. melaninogenica and Selenomonas sputigena were more frequently detected in molars. The bacterial species S. constellatus, G. morbillorum and P. magnus were isolated in greater numbers in incisors and P. micros, S. intermedius, Campylobacter concisus, Bacteroides egertheii, B. forsythus, P. oralis and S. sputigena were isolated in greater numbers in molars, respectively. Cluster analysis revealed 4 clusters in which 6–7 bacterial species were elevated above mean levels. Cluster I was predominated by S. constellatus, S. mitis, S. sanguis, G. morbillorum, P. melaninogenica and P. oralis; cluster II was predominated by S. sanguis, Actinomyces naeslundii, Capnocytophaga gingivalis, C. ochracea and P. intermedia; cluster III was predominated by S. mitis, C. ochracea, F. nucleatum, P. loeschei, P. melaninogenica and P. oralis; and finally cluster IV was predominated by S. sanguis, C. gingivalis, Veillonella parvula, Campylobacter gracilis, F. nucleatum and P. intermedia. The bacterial species S. constellatus, P. micros, Pseudoramibacter alactolyticus, Eikenella corrodens and F. nucleatum were associated with non‐bleeding sites while S. intermedius, C. concisus, P. intermedia and P. loescheii were found more frequently in bleeding sites.
Storage conditions of avulsed teeth affect the phenotype of cultured human periodontal ligament cells
Authors: Lin D. G. , Kenny D. J. , Barrett E. J. , Lekic P. , McCulloch C. A. G.
Published: December 2003

After severe injury to the periodontal ligament (PL), the phenotypes of cells recolonizing root surfaces influence the extent and type of repair processes. In teeth that are replanted following avulsion injury, recolonization of the PL space by osteogenic cells instead of by PL fibroblasts may favor bone formation (i.e. ankylosis) instead of PL regeneration. We consider here that recolonization processes depend in part on the storage conditions of the teeth following avulsion. We used an in vitro cell culture model to assess the effect of storage conditions on immunohistochemical staining of several marker proteins that are expressed by osteogenic cells (osteopontin and alkaline phosphatase) and fibroblasts (α‐smooth muscle actin, type III and XII collagens). Prior to cell culture, extracted human premolar teeth were stored in air (“dry”) or in α‐MEM (“wet”) for either 30 or 120 min as surrogate conditions for the variations of extra‐alveolar tooth storage that may occur following avulsion. Collagenase/trypsin‐digested suspensions of PL cells were prepared from the tissue adherent to the extracted root surface. Passage #2 or #3 cultures were immunostained and examined by fluorescence microscopy. For type XII collagen, cells from wet samples displayed perinuclear staining while cells from 30‐min dry samples showed only isolated foci. The staining for 120‐min dry samples was weak and non‐specific. α‐Smooth muscle actin was not incorporated into stress fibers in wet samples, whereas dry samples demonstrated prominent stress fibers stained for α‐smooth muscle actin. Detached cytoplasmic fragments resembling cell processes that stained for α‐smooth muscle actin were abundant in dry samples, indicating the presence of highly contractile cells. The staining for osteopontin was mainly perinuclear but was more intense in dry samples. The focal adhesion pattern of osteopontin staining in 120‐min dry samples resembled that of migrating osteogenic cells. The pattern of staining did not vary for type III collagen or alkaline phosphatase, although staining for alkaline phosphatase was more intense in samples stored under dry conditions. We conclude that prolonged extra‐alveolar dry storage favors increased in vitro growth of contractile cells expressing osteogenic cell markers while storage in cell culture medium favors growth of cells with the classical phenotype of PL fibroblasts.
The fibrous structure of the cemento–dentinal junction in human molars shown by scanning electron microscopy combined with NaOH‐maceration
Authors: Yamamoto T. , Domon T. , Takahashi S. , Islam M. N. , Suzuki R.
Published: December 2003

The cemento–dentinal junction was studied in acellular and cellular cementum of human mandibular third molars by scanning electron microscopy combined with NaOH‐maceration. Scanning electron microscopy with NaOH‐maceration was applied to observe the fibrous structure in detail through long sections of the cemento–dentinal junction. In macerated specimens, the cemento–dentinal junction was a fibril‐poor groove. Some cemental fibrils or fibril bundles penetrated the groove and appeared to intermingle with dentinal fibrils. Prolonged maceration caused detachment of the cemento–dentinal junction irrespective of fibril intermingling allowing observation of the inner cementum surface facing the root dentin. Observations suggested that the fibril intermingling was point‐like and present only in places at the cemento–dentinal junction. It was established that NaOH‐maceration removes interfibrillar substances effectively in connective tissues and does no damage to the collagen fibril structure and architecture. This study showed the 3‐dimensional fibrous structure of the cemento–dentinal junction in human mandibular third molars, and suggested that interfibrillar adhesive substances are more important than the fibril intermingling for the cemento–dentinal attachment.
Polymorphonuclear leukocyte degranulation induced by leukotoxin from Actinobacillus actinomycetemcomitans
Authors: Johansson A. , Claesson R. , Hänström L. , Sandström G. , Kalfas S.
Published: December 2003

The ability of leukotoxin from Actinobacillus actinomycetemcomitans to induce release of lysosomal constituents was studied with human polymorphonuclear leukocytes (PMNL). Leukotoxin purified from A. actinomycetemcomitans or bacterial cells of a leukotoxic strain were mixed with human PMNL and the suspension was incubated under anaerobic conditions. Samples were taken at certain time intervals to examine the cell morphology of PMNL by electron microscopy and the extracellular concentrations of the granule components lactoferrin and elastase by enzyme‐linked immunosorbent assay (ELISA). Electron microscopy revealed that within 10 min of exposure to leukotoxin, the number of intracellular granules was markedly reduced and the remaining granules were translocated to the periphery in PMNL. At the same time, the extracellular concentrations of lactoferrin and elastase were elevated, while that of the cytosolic enzyme lactate dehydrogenase, an indicator of cell lysis, remained low. The lysosome molecules CD63 and CD66b were also exposed on the PMNL surface, indicating fusion of lysosomes with the plasma membrane. These effects were completely abolished by the addition of anti‐leukotoxin serum. Pre‐incubation of PMNL with monoclonal antibodies to CD11a and CD18 that recognize α‐ and β‐ chains of the LFA‐1 integrin, a leukotoxin receptor on PMNL, inhibited the cytolysis, but not the release of granule components. The present results demonstrate the ability of A. actinomycetemcomitans leukotoxin to trigger a rapid release of lysosomal compounds in human PMNL. The release is due to an active process stimulated by the interaction of PMNL with the toxin or toxin‐carrying bacteria.
Adenosine regulates the production of interleukin‐6 by human gingival fibroblasts via cyclic AMP/protein kinase A pathway
Authors: Murakami Shinya , Terakura Mami , Kamatani Takeyuki , Hashikawa Tomoko , Saho Teruyuki , Shimabukuro Yoshio , Okada Hiroshi
Published: December 2003

Adenosine has been reported to alter a variety functions of the cells that participate in inflammatory responses. However, the effect(s) of adenosine on human gingival fibroblasts (HGF), one of the immunomodulator cells in inflamed periodontal lesions, remains to be established. In this study, we examined the influence of adenosine on the production of interleukin (IL)‐6 by HGF. Ligation of adenosine receptors with adenosine or its related analogue, 2‐chloroadenosine (2‐CADO), increased IL‐6 production by HGF without any other stimuli. In addition, adenosine and 2‐CADO enhanced the cyclic AMP (cAMP) level in HGF as did prostaglandin E1(PGE1) and forskolin. Interestingly, these cAMP‐arising reagents and the permeable cAMP analogue, dibutyryl cAMP (dbtcAMP), also increased IL‐6 production by HGF. These results suggest that cAMP is involved in adenosine‐ induced IL‐6 production by HGF. Adenosine‐induced IL‐6 production was suppressed by protein kinase A (PKA) inhibitor, H89, indicating that cAMP/PKA pathway is involved in the induction. Moreover, the experiments using antagonists specific for adenosine receptor subtypes revealed that the adenosine‐induced IL‐6 production by HGF was, at least in part, mediated by the adenosine A2b receptor. These results provide new evidence for the possible effects of adenosine or its related analogue as an immunomodulator in inflammatory periodontal lesions.
Effect of interleukin‐1 gene polymorphisms on gingival inflammation assessed by bleeding on probing in a periodontal maintenance population
Authors: Lang Niklaus P. , Tonetti Maurizio S. , Suter Judith , Sorrell Julian , Duff Gordon W. , Kornman Kenneth S.
Published: December 2003

Bleeding on probing (BOP) is the most significant clinical parameter for the assessment of periodontal inflammation. The aim of this prospective longitudinal trial was to study the association between allelic variants of the IL‐1 gene complex and gingival inflammation. Three hundred and twenty‐three randomly selected periodontal maintenance patients (64.4% females) received a periodontal examination that included probing depth measurements and BOP at each of 4 supportive periodontal therapy (SPT) appointments. A blood sample taken from each subject was analysed for the presence of specific allotypes of the IL‐1 gene complex. Two polymorphisms located at +4845 bp in the IL‐1α region and at +3954 bp in the IL‐1β region were evaluated by a polymerase chain reaction method; 35.3% of the examined subjects were positive for specific combinations of allotypes of the IL‐1 gene complex previously associated with an increased risk for severe periodontitis. The population consisted of 90 current smokers and 94 former smokers. An analysis of the association between the IL‐1 genotype and BOP in the whole population (including smokers) did not reach statistical significance because of the overriding effect of smoking. A subset analysis of the 139 never smokers indicated that genotype positive patients had a significantly elevated chance of presenting an increase in the BOP% over a 4‐appointment recall period (p=0.03) after correcting for oral hygiene. In fact, patients who were genotype‐negative had a 50% smaller chance of showing increases in BOP% during SPT. A further analysis explored the relationship between the genotype and the level of BOP% at the most recent recall visit. A generalized linear model showed a statistically significant effect of the genotype status after correcting for plaque accumulation and prevalence of residual pockets (≥5 mm). Genotype‐negative subjects had significantly lower BOP%(p=0.0097). It is concluded that the increased BOP prevalence and incidence observed in IL‐1 genotype‐positive subjects indicates that some individuals have a genetically determined hyper‐inflammatory response that is expressed in the clinical response of the periodontal tissues.
Despite large‐scale T cell activation, only a minor subset of T cells responding in vitro to Actinobacillus actinomycetemcomitans differentiate into effector T cells
Authors: Zadeh Homayoun H. , Tanavoli Sara , Haines David D. , Kreutzer Donald L.
Published: December 2003

Recent studies in our laboratory have demonstrated that Actinobacillus actinomycetemcomitans has a potent T cell stimulatory effect, activating more than half of all T cells. However, since the fate of these activated T cells was not known, the present study sought to determine whether all of these T cells differentiate into effector cells. To that end, the intracellular expression of T cell cytokines (IL‐2, IFN‐γ, IL‐4 and IL‐10) in response to A. actinomycetemcomitans was determined by flow cytometry. Results demonstrated a time‐dependent increase in the expression of the cytokines, most reaching peak levels at 24–48 h. At 48 h, the proportion of T cells expressing each of the cytokines were as follows: IL‐2 (1.7%±0.3), IFN‐γ(1.8%±0.5), IL‐4 (1.0%±0.2) and IL‐10 (1.5%±0.5). These data indicated that only 2–5% of all T cells stimulated with A. actinomycetemcomitans expressed any T cell cytokines. The finding of large‐scale T cell activation in the absence of cytokine expression suggests that the activation of T cells in response to A. actinomycetemcomitans is incomplete. To investigate this phenomenon, peripheral blood mononuclear cells (PBMC) were cultured with A. actinomycetemcomitans for 24 h followed by sorting of the activated (CD69+) cells by immunomagnetic separation and restimulation with phorbol 12‐myristate 13‐acetate (PMA) and ionomycin. Results demonstrated that nearly 90% of the T cells were unresponsive to further restimulation. A possible explanation for this unresponsiveness is the induction of clonal anergy among the responding T cells. To determine possible preferential effects of the stimulation on specific cytokines, the expression of each cytokine among T cells responding to A. actinomycetemcomitans was compared to the maximum levels achieved by PMA+ionomycin stimulation. Results showed that number of IL‐2+ and IFN‐γ+ T cells observed in response to A. actinomycetemcomitans were between 2% and 7% of those seen in response to PMA+ionomycin. Conversely, the proportions of T cells expressing IL‐4 or IL‐10 were between 35% and 90% of those following stimulation with PMA+ionomycin. Hence, A. actinomycetemcomitans appears to more preferentially induce T cells
C5a modulation of interleukin‐1β‐induced interleukin‐6 production by human osteoblast‐like cells
Authors: Pobanz John M. , Reinhardt Richard A. , Koka Sreenivas , Sanderson Sam D.
Published: December 2003

Periodontal bone resorption is controlled by osteoblast products, including interleukin (IL)‐6, which are stimulated by other cytokines and complement components in the pro‐inflammatory milieu. This study demonstrated that human osteoblast‐like osteosarcoma cells (MG‐63) responded to human recombinant (hr) C5a by releasing significant amounts of the bone‐resorbing cytokine IL‐6. C5a‐induced release of IL‐6 was enhanced 330% when cells were exposed to IL‐1β prior to C5a challenge at optimal concentrations (1.0 μg/ml C5a, 0.1 ng/ml IL‐1β). Cells simultaneously challenged with these concentrations of C5a and IL‐1β produced a 700% increase in IL‐6 release relative to cells challenged with IL‐1β alone. Incubation of IL‐1β‐treated cells with anti‐human C5a receptor (C5aR) Ab resulted in a 78% suppression of the C5a‐induced release of IL‐6, but C5aR neutralization did not affect C5a/IL‐1β co‐stimulation of IL‐6. In addition, neither IL‐1β nor C5a significantly altered the other's cell‐surface receptor relative to binding affinity or density. These results indicate that while MG‐63 cells express functional C5aRs, the synergistic effect of C5a and IL‐1β on osteoblast IL‐6 production is probably controlled by post‐receptor signaling events. C5a agonists and antagonist used to alter critical C5a concentrations may present a new point of therapeutic intervention for the treatment of inflammatory bone resorption such as is found in periodontitis.
Human gingival glycosaminoglycans in cyclosporin‐induced overgrowth
Authors: Rocha Lia A. G. , Martins Rita C. L. , Werneck Claudio C. , Feres‐Filho Eduardo J. , Silva Luiz‐Claudio F.
Published: December 2003

Glycosaminoglycans in normal and cyclosporin‐induced gingival overgrowth were extracted by papain digestion and purified by Mono Q‐FPLC chromatography. The purified glycosaminoglycans were analyzed by agarose gel electrophoresis and by the pattern of degradation products formed by chondroitin lyases on HPLC chromatography. Our results on the glycosaminoglycan composition showed presence of chondroitin 4‐ and 6‐sulfate, dermatan sulfate, heparan sulfate and hyaluronic acid in both normal gingiva and cyclosporin‐induced gingival overgrowth. The total and relative amounts of glycosaminoglycans were similar between normal and overgrown gingiva. This suggests that the glycosaminoglycan composition is not changed in cyclosporin‐induced gingival overgrowth. Our present biochemical results conflict with histochemical and biosynthetic data previously reported by other groups. Those studies suggested that the affected tissues contained higher levels of glycosaminoglycans and that cyclosporin induced comparably high levels of these compounds in in vitro cultures of gingival fibroblasts. Therefore, these discrepant results suggest that a cyclosporin‐induced increase on gingival glycosaminoglycans still remains an open question. The implications of these conflicting results are discussed.
Expression of Tie‐2, angiopoietin‐1, angiopoietin‐2, ephrinB2 and EphB4 in pyogenic granuloma of human gingiva implicates their roles in inflammatory angiogenesis
Authors: Yuan Kuo , Jin Ying‐Tai , Lin Ming T.
Published: December 2003

Tie‐2, angiopoietin‐1 (Ang‐1), angiopoietin‐2 (Ang‐2), ephrin‐B2 and Eph‐B4 are all important vascular morphogenesis factors which exhibit their functions in angiogenesis and blood vessel remodeling in embryonic stage. However, their roles in post‐natal inflammatory angiogenesis are still unclear. Pyogenic granuloma is a benign inflammatory lesion that mostly occurs on the gingiva of females with high levels of steroid hormones. Prominent capillary growth in hyperplastic granulation tissue is characteristic histopathologically in pyogenic granuloma. The purpose of this study was to detect and compare the expressions of Tie‐2, Ang‐1, Ang‐2, ephrin‐B2 and Eph‐B4 among pyogenic granuloma on human gingiva, gingiva diagnosed with periodontitis and healthy gingiva by immunohistochemistry. The immunostaining revealed that all of the endothelial cells and some mesenchymal cells expressed Tie‐2. The cells which expressed Ang‐1 and Ang‐2 were mainly macrophage‐ or monocyte‐like mesenchymal cells and smooth muscle cells surrounding blood vessels. The expression of ephrin‐B2 and Eph‐B4 was not exclusively limited to the endothelial cells of arteries and veins, respectively, as in mice embryo. Eph‐B4 was expressed in the endothelial cells of newly budding capillaries and venules while ephrin‐B2 was expressed in macrophage‐like mesenchymal cells. Some of the ephrin‐B2 positive cells were in direct contact with endothelial cells. The statistical analysis demonstrated that all of the five factors were upregulated in pyogenic granuloma compared to healthy gingiva. In conclusion, the 5 polypeptides mentioned above may play important roles in the process of adult inflammatory neovascularization, especially in pyogenic granuloma. It is highly plausible that most of the new capillaries in inflammatory angiogenesis originated from venules instead of arterioles.
Effect of the interleukin‐1 genotype on monocyte IL‐1β expression in subjects with adult periodontitis
Authors: Mark Laura L. , Haffajee Anne D. , Socransky Sigmund S. , Kent Ralph L. , Guerrero Denise , Kornman Kenneth , Newman Michael , Stashenko Philip
Published: December 2003

An association has been reported between polymorphisms in the genes encoding IL‐1α(−889) and IL‐1β(+3953)(periodontitis susceptibility trait, PST), and an increased severity of periodontitis (18). The IL‐1β polymorphism was reported to correlate with increased IL‐1β expression by monocytes in response to bacterial stimulants. In the present study, we determined if PST positive subjects with periodontitis exhibit elevated production of IL‐1β, compared to PST negative periodontitis patients. Peripheral blood monocytes were obtained from 10 PST+ and 10 PST− age‐ and disease‐balanced subjects with adult forms of periodontitis. Monocytes were cultured with a panel of bacterial stimulants, including Escherichia coli and Porphyromonas gingivalis LPS, and whole formalinized periodontal pathogens P. gingivalis, Bacteroides forsythus and Prevotella intermedia, and health‐associated organisms Veillonella parvula and Streptococcus sanguis. Our results demonstrate that monocytes from PST+ and PST− patients showed no significant differences in IL‐1β production in response to any stimulant tested. In addition, the periodontal pathogens P. gingivalis, B. forsythus and P. intermedia failed to stimulate higher IL‐1β responses compared to health‐associated species V. parvula and S. sanguis. A marked interindividual variation in production of IL‐1β was seen, with high, low and intermediate responders present in both PST+ and PST− groups. We conclude that genetic loci other than the PST polymorphisms are also important regulators of monocyte IL‐1 responses.
Development of an opto‐electronic positioning device for serial direct digital images of oral structures
Authors: Morea C. , Langlotz F. , Scheer C. , Bürgin W. , Nolte L. P. , Lang N. P. , Brägger U.
Published: December 2003

The aim of this study was to develop and test in vitro an opto‐electronic positioning device for serial direct digital images of oral structures, i.e. to associate direct digital imaging with the principles of computer‐aided surgery. This system registered positions of infrared light emitting diodes (LED) on carriers, establishing local coordinate systems. With LED markers attached on the sensor holder, the X‐ray tube and a fix reference, the opto‐electronic camera (Optotrak®) registered the geometric source/detector relation. A specially designed tracking and guidance software was developed which enabled the operator to reposition the X‐ray source. A graphical user interface guided the operator in aligning 2 circles to the reference axis, one indicating the origin of the beam, the other its tip. In addition, depth control was provided. An in vitro calibration was performed. A sensor holder/bite block carried the Sens‐A‐Ray® sensor with a hair‐cross. In front of the object a second hair‐cross was fixed. A steel ball fixed to the center of the X‐ray cone allowed to verify the alignment. The mean angulation error in the vertical plane was 0.06° and 0.04° in the horizontal one. Translation mean errors were small and ranged between −0.02 mm and 0.37 mm. The translation in the Z axis is negligible. This resulted in pairs of images suitable for digital subtraction. Although still in an experimental state, the results showed that opto‐electronic navigation was useful to standardize projection geometry without any mechanical link and to achieve digital subtraction images based on direct digital imaging.
A novel closed‐tube quantitative–PCR method for enumerating Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans
Authors: Doung‐udomdacha S. , Rawlinson A. , Douglas C. W. I.
Published: December 2003

Enumeration of specific periodontopathogens in subgingival plaque samples has been problematic because of either lack of sensitivity, specificity or the time taken to identify the organisms. These problems can be overcome using PCR, but quantification by this technique is more difficult. We report a simple quantitative PCR method developed for enumerating Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans in clinical samples. The method relies upon inclusion of ethidium bromide in a closed‐tube PCR reaction and measurement of resultant amplicons by quantifying the fluorescence generated when UV‐light is passed through the walls of the amplification tube. Hence, both PCR and detection are performed in the same tube. The technique was compared with a quantitative–competitive PCR and a commercial colorimetric quantitative–PCR and proved to be at least as sensitive, specific and reliable for enumeration of the target bacteria. However, its speed and convenience make it particularly useful for large‐scale analyses in both clinical laboratories and epidemiological studies.
Cytostatic action of enamel matrix derivative (EMDOGAIN®) on human oral squamous cell carcinoma‐derived SCC25 epithelial cells
Authors: Kawase Tomoyuki , Okuda Kazuhiro , Yoshie Hiromasa , Burns Douglas M.
Published: December 2003

During surgical treatment of periodontal disease, enamel matrix derivative (EMD) is topically applied as a substitute for extracellular matrix in order to facilitate regeneration of damaged periodontal tissue. However, the mechanism for EMD action is poorly understood. We have now examined the effects of EMD on the proliferation of oral epithelial (SCC25) cells in vitro. After 3 days of treatments, EMD (25–100 μg/ml) dose‐dependently inhibited cell division and concomitantly arrested cell cycle at the G1 phase. Prior to this inhibition, EMD significantly up‐regulated p21WAF1/cip1, a cyclin‐dependent kinase inhibitor, induced G1‐arrest, and inhibited DNA synthesis. In addition, EMD down‐regulated expression of cytokeratin‐18 (CK18) protein, which was most due to decreased production, but less to increased degradation. However, EMD did not discernibly increase the number of apoptotic cells over 8 days of treatment. These findings indicate (1) that EMD acts as a cytostatic agent, rather than a cytotoxic agent, on epithelial cells, and (2) that this anti‐proliferative action is probably due to p21WAF1/cip1‐mediated G1‐arrest. Furthermore, our in vitro cellular data clearly verify and provide an explanation for the clinical observation that EMD application suppresses the down‐growth of junctional epithelium onto dental root surfaces, a process that frequently interferes with the formation of new connective tissue attachments.
Improvement of macromolecular clearance via lymph flow in hamster gingiva by topical warming and massage
Authors: Shimotoyodome A. , Meguro S. , Hase T. , Tokimitsu I. , Fujimura A. , Nozaka Y.
Published: December 2003

The lymphatic system is very important for macromolecular clearance in various tissues, especially in the gingiva. However, the kinetics of macromolecular clearance via the lymph flow in the gingiva are poorly understood. The aim of this study was to investigate whether thermal or mechanical stimulation affects macromolecular clearance via the lymph flow in the gingiva. Carbon black suspension was injected into the mandibular gingiva of anesthetized hamsters and its drainage into cervical lymph nodes was examined. Clearance of 14C‐methylated bovine albumin and tritiated water from the gingiva and their drainage into submandibular lymph nodes and blood was quantified. The effect of topical warming or massage on clearance of 14C‐methylated albumin from the gingiva during a 15 min period was examined. In addition, the influence of neurochemical antagonists on the stimulatory effect of topical warming on albumin clearance was investigated. Submandibular lymph nodes were clearly delineated by carbon black 10 min after the injection. More radiolabeled albumin appeared in submandibular lymph nodes than in serum, while more tritiated water appeared in serum. Topical warming (45°C, 2 min) and warming plus massage (with a silicon rubber brush, 20 s) decreased the radiolabeled albumin in the gingiva 15 min after the injection. There was less radiolabeled albumin in the gingiva after gingival warming plus massage than after warming. Previous injection of HOE140 or propranolol into the gingiva diminished the stimulatory effect of topical warming on albumin clearance. It was concluded that topical warming plus massage improves macromolecular clearance via the lymph flow in hamster gingiva.
Inducible nitric oxide synthase expression in periodontitis
Authors: Lappin D. F. , Kjeldsen M. , Sander L. , Kinane D. F.
Published: December 2003

Recently, nitric oxide (NO) has been shown to be vital in inflammatory processes. Nitric oxide synthase (NOS) exists in three different isoforms, two constitutively produced with physiological roles, and an inducible form, iNOS, which is involved in inflammation. This study examined the localisation of iNOS in biopsies from patients with periodontitis using immunohistochemistry, and compared these with healthy tissue biopsies. Biopsies were obtained from 16 periodontitis patients undergoing periodontal surgery and from clinically healthy tissues of 5 patients having crown lengthening procedures. The periodontitis diseased tissue demonstrated a greater level of iNOS expression than the healthy tissue. The source of iNOS in the periodontal tissues was determined by our monoclonal antibody to be the macrophage, with the endothelial cells also contributing. A role for NO in the inflammatory response of periodontal tissues is suggested, but the precise role requires further elucidation.
Robert Gilpin (2002) The Challenge of Global Capitalism. The World Economy in the 21st Century
Authors: Rossini Gianpaolo
Published: December 2003

Book reviewed in this article:

Robert Gilpin, The Challenge of Global Capitalism. The World Economy in the 21st Century
Feature
Authors: Grady Monica M.
Published: December 2003

Over the past decade, planets have been discovered that orbit other stars, a vast ocean has been detected below the icy crust of Jupiter's satellite, Europa, and fossils have been reported in a rock from Mars. On Earth, micro‐organisms have been identified that inhabit environments previously thought to be too inhospitable to support life. All these observations have helped to define the interdisciplinary subject that has come to be known as astrobiology.
Building diverse community networks for sustainable food systems: Guiding philosophies of the Pennsylvania Association for Sustainable Agriculture
Authors: Carnes Laura M. , Karsten Heather D.
Published: December 2003

The Pennsylvania Association for Sustainable Agriculture (PASA) is a grassroots organization that facilitates the exchange of sustainable farming practices among its members, creates marketing opportunities for local farmers, and promotes consumer awareness and support for sustainable agriculture. Interviews with PASA's board members and staff, content analyses of PASA's literature, and a mail survey and spatial analysis of PASA's members—who include both farmers and members who do not farm—were used to examine members' characteristics, why they value being members, and the philosophies and strategies that guide the organization's successes. Results indicate that by embracing a broad definition of sustainable agriculture, PASA promotes profitable and environmentally sound farming practices to a diversity of farmers. Networking with a broad cross-section of local and regional organizations and institutions has enabled PASA to use the expertise of community leaders and share fundraising to develop marketing opportunities for farmers. Linking sustainable agriculture with priorities of community economic development has brought farmers to urban planning tables, increased inner city access to fresh, local food, and increased the economic viability of local farmers. PASA's experiences exemplify the opportunities and tensions involved with networking with mainstream institutions to gain greater support for the sustainable agriculture community. PASA provides one model of how sustainable agriculture organizations can play an integral role in supporting sustainable agriculture.
Economic viability of the traditional farming system in the Ghouta, Oasis of Damascus, Syria
Authors: Alhamidi Sameer K. , Håkansson Bengt , Gustafsson Mats
Published: December 2003

The traditional farming system (TFS) in the Ghouta has been an integral pan of the social life and has contributed to the food supply of Damascus for millennia. Very little is known about this traditional and sustainable system, considered by many as a hindrance to development. This study is an attempt to analyze the economic perfonnance of this system. The objective is to evaluate the economic performance of the TFS and its impact on system viability. Three farms, representing the three different agricultural strategies in this area, were selected for data-collection. Participant observation was used to derive estimates of labor, costs and revenues, which are not recorded by farmers. These three farms formed a base for continuous contact with other farmers in the Ghouta. The average values, after cross-checking with these estimates and other farmers, were used in the economic analysis at three levels: production, family and market level. The production system of the Ghouta is adaptable to economic forces of a major city as the high level of market orientation of the TFS stimulates diversity of farms. It is concluded that the diversified farms managed by farmers in this area provide a satisfactory income, which is in harmony both with the social values and with preserving the system, the overall objective of the farmers.