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We have extended our studies of Trp/Trp to other Aryl/Aryl through-space interactions that stabilize hairpins and other small polypeptide folds. Herein we detail the NMR and CD spectroscopic features of these types of interactions. NMR data remains the best diagnostic for characterizing the common T-shape orientation. Designated as an edge-to-face (EtF or FtE) interaction, large ring current shifts are produced at the edge aryl ring hydrogens and, in most cases, large exciton couplets appear in the far UV circular dichroic (CD) spectrum. The preference for the face aryl in FtE clusters is W ≫ Y ≥ F (there are some exceptions in the Y/F order); this sequence corresponds to the order of fold stability enhancement and always predicts the amplitude of the lower energy feature of the exciton couplet in the CD spectrum. The CD spectra for FtE W/W, W/Y, Y/W, and Y/Y pairs all include an intense feature at 225-232 nm. An additional couplet feature seen for W/Y, W/F, Y/Y, and F/Y clusters, is a negative feature at 197-200 nm. Tyr/Tyr (as well as F/Y and F/F) interactions produce much smaller exciton couplet amplitudes. The Trp-cage fold was employed to search for the CD effects of other Trp/Trp and Trp/Tyr cluster geometries: several were identified. In this account, we provide additional examples of the application of cross-strand aryl/aryl clusters for the design of stable β-sheet models and a scale of fold stability increments associated with all possible FtE Ar/Ar clusters in several structural contexts. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 337-356, 2016.

Democracy Prevention: The Politics of the U.S.-Egyptian Alliance. By Jason Brownlee. Cambridge, UK: Cambridge University Press, 2012. 279 pp., $30.99 paperback (ISBN-13: 978-1-107-67786-9). Beyond the Arab Spring: Authoritarianism and Democracy in the Arab World. By Rex Brynen, Pete W. Moore, Bassel F. Salloukh, Marie-Joelle Zahar. Boulder, CO: Lynne Rienner, 2012. 349 pp., $27.50 paperback (ISBN-13: 978-1-588-26878-5). Out of the wave of literature on the Arab uprisings—some of which is forgettable as “instant history”—I cannot think of two better books than those under review here. They are quite different but they complement each other. Jason Brownlee has a story to tell: how the United States consistently has favored authoritarianism over democratization in Egypt. The coauthors of Beyond the Arab Spring —Rex Brynen, Pete Moore, Bassel Salloukh, and Marie-Joelle Zahar (assisted by Janine Clark)—contextualize the uprisings in terms of ongoing debates on political science about persistent authoritarianism and transitions. Along the way, they explore the role of political culture, Islamist movements, the new media, and the international community, among other things. Together, these volumes provide the student or general reader with both the empirical depth of a case study and the theoretical breadth of a survey. The first part of Beyond the Arab Spring provides a succinct summary of the uprising trajectories in Tunisia, Egypt, Libya, Yemen, Bahrain, and Syria through 2012. But the more valuable material is to be found in Part Two's insightful discussion of theoretical issues, and Part Three, where the authors offer some judicious if tentative conclusions about the “long road ahead” for the Arab world. Building on earlier work going back into the 1990s, the “Montreal school” of Brynen et al. offer nuanced commentaries on some of the leading propositions in comparative politics. They show that political culture, for example, needs to be treated not as something primordial but as contingent and constructed—and reconstructible. Oil wealth, they argue, is not a cause of authoritarian but rather a structural condition that distorts economies in a particular way that can privilege the incumbents and disadvantage a nascent civil society. One of the best chapters tackles the question of monarchies. In the post-uprising period, it has …

This paper explores the implications of the tectonic shifts in the global balance of power marked by the rise of China and India and the relative decline of American hegemony across the Indian Ocean region – bordered as it is by five continents and some 40 countries. Located at the Middle Eastern end of it are the strategic chokepoints of the Bab al-Mandab and the Strait of Hormuz, and at the Asian end the Strait of Malacca. However, while the Middle East and Asia are ever more interconnected across this third-largest ocean (and also along the reviving terrestrial ‘Silk Road’) through trade, finance and culture, the paper does not foresee an imminent confrontation in the Middle East between the rising Asian superpowers and the United States. Nonetheless, it is contended that President Barack Obama's dramatic ‘rebalancing’ project indicates that America intends to intensify its support for the small Asian states worried about China's assertiveness in the East and South China seas, while at the same time insisting that this ‘pivot’ does not mean a diminution of US power in the Middle East. For the time being, it seems that China and India are content to remain ‘free riders’ in the Middle East, uninterested in challenging the United States.

This chapter examines the roots of U.S. foreign policy in the Middle East. It begins with an overview of the origins and development of the United States’s involvement in the region over the past century, focusing on the traditional American interests. It then considers the structure of Middle Eastern policymaking and its domestic political context, as well as Washington’s response to new regional tensions and upheavals since the late 1970s. It also discusses new developments in the region, including the rise of the Islamic Republic of Iran, the Al-Qaeda and the 9/11 terrorist attacks, the U.S.-led interventions in Afghanistan and Iraq, and the Palestinian–Israeli impasse. The evolution of U.S. policy since 2000 in the administrations of George W. Bush and Barack Obama is explored as well. The chapter concludes with an analysis of an ‘Obama doctrine’ and ‘American decline’ in the Middle East and the world.

The contagion effect created by the regime changes in Tunisia, Egypt, and Libya suggests a significant degree of imagined community among Arabs everywhere.

Titanium alloys (Ti) are the preferred material for orthopaedic applications. However, very often, these metallic implants loosen over a long period and mandate revision surgery. For implant success, osteoblasts must adhere to the implant surface and deposit a mineralized extracellular matrix. Here, we utilized UV-killed Staphylococcus aureus as a novel osteoconductive coating for Ti surfaces. S. aureus expresses surface adhesins capable of binding to bone and biomaterials directly. Furthermore, interaction of S. aureus with osteoblasts activates growth factor-related pathways that potentiate osteogenesis. While UV-killed S. aureus cells retain their bone-adhesive ability, they do not stimulate significant immune modulator expression. All of the above properties were utilized for a novel implant coating so as to promote osteoblast recruitment and subsequent cell functions on the bone-implant interface. In the present study, osteoblast adhesion, proliferation, and mineralized extracellular matrix synthesis were measured on Ti surfaces coated with fibronectin with and without UV-killed bacteria. Osteoblast adhesion was enhanced on Ti alloy surfaces coated with bacteria compared to uncoated surfaces while cell proliferation was sustained comparably on both surfaces. Osteoblast markers such as collagen, osteocalcin, alkaline phosphatase activity and mineralized nodule formation were increased on Ti alloy coated with bacteria compared to uncoated surfaces.

Osteomyelitis is an inflammatory disease of the bone that is characterized by the presence of necrotic bone tissue and increased osteoclast activity. Staphylococcus aureus is responsible for approximately 80% of all cases of human osteomyelitis. While the disease is especially difficult to treat, the pathogenesis of S. aureus -induced osteomyelitis is poorly understood. Elucidating the molecular mechanisms by which S. aureus induces osteomyelitis could lead to a better understanding of the disease and its progression and development of new treatments. Osteoblasts can produce several soluble factors that serve to modulate the activity or formation of osteoclasts. Receptor activator of NF-κB ligand (RANK-L) and prostaglandin E 2 (PGE 2 ) are two such molecules which can promote osteoclastogenesis and stimulate bone resorption. In addition, previous studies in our laboratory have shown that osteoblasts produce inflammatory cytokines, such as interleukin 6, following infection with S. aureus , which could induce COX-2 and in turn PGE 2 , further modulating osteoclast recruitment and differentiation. Therefore, we hypothesized that following infection with S. aureus , osteoblasts will express increased levels of RANK-L and PGE 2 . The results presented in this study provide evidence for the first time that RANK-L mRNA and protein and PGE 2 expression are upregulated in S. aureus -infected primary osteoblasts. In addition, through the use of the specific COX-2 inhibitor NS 398, we show that when PGE 2 production is inhibited, RANK-L production is decreased. These data suggest a mechanism whereby osteoblasts regulate the production of RANK-L during infection.

Incidences of osteomyelitis caused by Staphylococcus aureus have increased dramatically in recent years, in part, due to the appearance of community-acquired antibiotic-resistant strains. Therefore, understanding the pathogenesis of this organism has become imperative. Recently, we have described the surprising ability of bone-forming osteoblasts to secrete a number of important immune mediators when exposed to S. aureus in vitro. In the present study, we provide the first evidence for the in vivo production of the pivotal inflammatory chemokine, monocyte chemoattractant protein-1 (MCP-1), by osteoblasts during S. aureus-associated bone infection. Quantitative real-time PCR was employed to determine levels of mRNA encoding MCP-1 in vivo using a mouse model that closely resembles the pathology of trauma-induced staphylococcal osteomyelitis. Expression of this inflammatory chemokine and osteoblast-specific markers was investigated by confocal laser scanning microscopy in bone tissue from organ cultures of neonatal mouse calvaria and from the in vivo mouse model. Furthermore, the clinical relevancy of these findings was investigated by performing similar studies on infected human bone tissue from patients with S. aureus-associated osteomyelitis. Here, we confirm that expression of mRNA encoding MCP-1 is elevated in bacterially infected murine bone tissue. Importantly, we show that these increases translate into marked elevations in the expression of MCP-1 protein that co-localizes with osteoblast markers in infected bone tissue. Such increases could not be attributed solely to mechanical damage as a similar response was observed in infected but otherwise undamaged organ cultures. Finally, we have demonstrated the in vivo production of MCP-1 by osteoblasts in bone specimens from patients with S. aureus-associated osteomyelitis. As such, these studies demonstrate that bacterial challenge of osteoblasts during bone diseases such as staphylococcal osteomyelitis induces cells to produce a key inflammatory chemokine that can direct appropriate host responses or may contribute to progressive inflammatory damage.

These contributions were presented at a roundtable of the Conference Group on the Middle East, “Evaluating the Bush Menu for Change in the Middle East,” at the American Political Science Association Annual Meeting, Chicago, September 5, 2004.

Staphylococcus aureus is the single most common cause of osteomyelitis in humans. Incidences of osteomyelitis caused by S. aureus have increased dramatically in recent years, in part due to the appearance of community-acquired antibiotic resistant strains. Therefore, understanding the pathogenesis of this organism has become imperative. Recently, we have described the surprising ability of bone-forming osteoblasts to secrete a number of important immune mediators when exposed to S. aureus in vitro. In the present study, we provide the first evidence for the in vivo production of such molecules by osteoblasts during bacterial infection of bone. These studies demonstrate the expression of the key inflammatory cytokine interleukin-6 by osteoblasts in organ cultures of neonatal mouse calvaria, and in vivo using a mouse model that closely resembles the pathology of trauma-induced staphylococcal osteomyelitis, as determined by confocal microscopic analysis. Importantly, we have established the clinical relevancy of these findings in infected human bone tissue from patients with S. aureus-associated osteomyelitis. As such, these studies demonstrate that bacterial challenge of osteoblasts during bone diseases, such as osteomyelitis, induces cells to produce inflammatory molecules that can direct appropriate host responses or contribute to progressive inflammatory damage.

A growing body of evidence has shown that bacterially challenged osteoblasts can play a significant role in the initiation of inflammatory immune responses at sites of bone disease. We have recently demonstrated the surprising ability of osteoblasts exposed to bacteria to express CD40, a molecule that plays a critical costimulatory role in the activation of T lymphocytes. In the present study, we have extended our investigations into the ability of osteoblasts to interact with CD4+ T lymphocytes by determining the expression of antigen-presenting major histocompatibility complex (MHC) class II molecules in murine and human osteoblasts following exposure to two common pathogens of bone, Staphylococcus aureus and Salmonella. Cultured osteoblasts were found to respond rapidly to bacterial challenge by induction of mRNA encoding MHC class II molecules or its transcriptional regulator. Increased mRNA expression translated into expression of MHC class II proteins in murine and human osteoblasts as determined by Western blot analysis and by immunohistochemical and immunofluorescent microscopy. Furthermore, the increased surface expression of these molecules on osteoblasts exposed to bacteria was confirmed by FACS analysis. Finally, we show that bacterial challenge results in the elevated functional expression of MHC class II molecules on osteoblasts by demonstrating the enhanced ability of these cells to interact with T lymphocytes and to initiate antigen-specific T cell activation. Taken together, these data suggest a previously unappreciated role for osteoblasts in the initiation of T lymphocyte activation at sites of bacterial infection in bone tissue.

Staphylococcus aureus is the bacterial pathogen which is responsible for approximately 80% of all cases of human osteomyelitis. It can invade and remain within osteoblasts. The fate of intracellular Staph. aureus after the death of the osteoblast has not been documented. We exposed human osteoblasts to Staph. aureus. After infection, the osteoblasts were either lysed with Triton X-100 or trypsinised. The bacteria released from both the trypsinised and lysed osteoblasts were cultured and counted. Colonies of the recovered bacteria were then introduced to additional cultures of human osteoblasts. The number of intracellular Staph. aureus recovered from the two techniques was equivalent. Staph. aureus recovered from time zero and 24 hours after infection, followed by lysis/trypsinisation, were capable of invading a second culture of human osteoblasts. Our findings indicate that dead or dying osteoblasts are capable of releasing viable Staph. aureus and that Staph. aureus released from dying or dead osteoblasts is capable of reinfecting human osteoblasts in culture.

The following is an edited transcript of the thirty-second in a series of Capitol Hill conferences convened by the Middle East Policy Council. The meeting was held on April 11, 2003, in the Dirksen Senate Office Building with Chas. W. Freeman, Jr., moderating.

Bacterially induced bone infections often result in significant local inflammatory responses which are coupled with loss of bone. However, the mechanisms necessary for the protective host response, or those responsible for pathogen-induced bone loss, are not clear. Recent evidence demonstrates that bacterially infected osteoblasts secrete chemokines and cytokines, suggesting that these cells may have an unappreciated role in supporting localized inflammation. In this study, mouse and human osteoblasts were investigated for their ability to express functional CD40 upon exposure to two important pathogens of bone,Staphylococcus aureusandSalmonella entericaserovar Dublin. Bacterial infection of cultured mouse or human osteoblasts resulted in increased CD40 mRNA and CD40 protein expression induced by either pathogen. Importantly, CD40 expression by osteoblasts was functional, as assessed by ligation of this molecule with recombinant, soluble CD154. CD40 activity was assessed by induction of interleukin-6 and granulocyte-macrophage colony-stimulating factor in osteoblasts following ligation. Cocultures of activated CD4+T lymphocytes and osteoblasts could interact via CD40 and CD154, since an antibody against CD40 could block macrophage inflammatory protein-1α secretion. Taken together, these studies conclusively demonstrate that infected osteoblasts can upregulate expression of functional CD40 molecules which mediate cytokine secretion. This surprising result further supports the notion that bone-forming osteoblasts can directly interact with CD154-expressing cells (i.e., T lymphocytes) and can contribute to the host response during bone infection.

Interactions between cells and biomaterials are affected by surface properties. Therefore, various approaches have been introduced for surface modifications. Here a technique based on ion beam lithography to improve osteoblast cell adhesion on polymeric materials is reported. We have demonstrated that exposing the polymer to P+ or Ar+ ions through masks can generate micro/nano-scale patterns. Our results illustrate that after exposure to an ion beam, the amount of osteoblast cells attached to the polymer was enhanced as a consequence of the roughened surface as well as due to the implanted ions. This indicates that masked ion beam lithography (MIBL) can not only generate nanostructures on the surface of a biocompatible polymer, but can also selectively modify the surface chemistry by implanting with specific ions. These factors can contribute to an osteogenic environment.

The following is an edited transcript of the twenty–ninth in a series of Capitol Hill conferences convened by the Middle East Policy Council. The meeting was held on June 14, 2002, in the Russell Senate Office Building with Chas. W. Freeman, Jr., moderating.

For political scientists studying the Middle East, the invitation to discuss the possible relevance of their work to comparative politics in general is a welcome and rare opportunity. There is, one senses, a gap between the Middle East political science community and the mainstream disciplinary generalists. To the extent that they even care about being part of the field, some Middle East political scientists feel ghettoized—their region and their work are ignored. Some feel as well that mainstream comparative politics theorizing has not offered much toward better understanding to Middle East politics. Such concerns motivated the establishment of the Conference Group on the Middle East, which organizes sessions in conjunction with, yet separate from, the main program at the APSA Annual Meeting. It is noteworthy that some of the most imaginative recent work on Middle East politics draws from anthropology, political economy, social history, and critical cultural and literary theory. “The Middle East political science community” is not populated exclusively by political scientists.

A Response to Navigating Through Turbulence: America and the Middle East in a New Century. Report of the Presidential Study Group (The Washington Institute for Near East Policy, 2001)

Two common pathogens of bone, Staphylococcus aureus and Salmonella, were investigated for their ability to induce chemokine expression in bone-forming osteoblasts. Cultured mouse or human osteoblasts could rapidly respond to bacterial infection by upregulating the mRNA encoding the chemokine, monocyte chemoattractant protein-1 (MCP-1). This rapid induction occurred on infection with either the gram-positive pathogen, S. aureus, or the gram-negative pathogen, Salmonella. Increased mRNA expression translated into MCP-1 secretion by cultured mouse or human osteoblasts in response to viable bacteria, whereas UV-killed bacteria were less effective in stimulating chemokine secretion. There was a dose-response relationship observed between the amount of input bacteria and increases in MCP-1 secretion. Immunohistochemical staining of infected osteoblasts indicated that the majority of cells could express MCP-1, with some osteoblasts having a higher intensity of staining than others. Organ cultures of mouse calvaria (skullcap) bone showed increases in MCP-1 immunostaining following bacterial infection. The immunoreactive MCP-1 in infected calvaria localized to areas containing active osteoblasts. Taken together, these studies demonstrate a conserved osteoblast-derived MCP-1 response to two very different pathogens of bone.

Staphylococcus aureus invades osteoblasts and is the primary cause of osteomyelitis. This study examined the ability of S. aureus to induce apoptosis in a mouse osteoblast cell line. The presence of intracellular S. aureus was demonstrated by transmission electron microscopy. Light microscopy was utilized to examine morphological changes in the osteoblasts following killing of extracellular bacteria. Cell rounding was observed, and dark centers due to condensation of chromatin were noted in cells in infected osteoblast cultures. DNA was isolated from infected osteoblast cultures, and electrophoresis revealed the laddering effect characteristic of cells undergoing apoptosis. Additionally, an in situ cell death detection assay was utilized to label apoptosis-induced DNA strand breaks. Apoptotic nuclei were present, providing further evidence that S. aureus induces apoptosis in osteoblasts.

Staphlylococcus aureus is the primary pathogen associated with osteomyelitis, an acute and recurrent bone disease. Internalization of S. aureus by cultured embryonic chick calvarial osteoblasts has been observed. The purpose of this study was to demonstrate that internalization of bacteria by embryonic chick calvarial and tibial osteoblasts occurs in vivo. In initial experiments, 10(8) colony forming units (cfu) of S. aureus, strain UAMS-1 or Cowan 1, were injected subcutaneously under the scalp skin of 17 day chick embryos. After 45 min, calvariae were harvested and processed for transmission electron microscopy (TEM). In subsequent experiments, 10(9) cfu of UAMS-1 were injected into the allantoic sac of 17 day chick embryos via a small opening in the egg shell. After 48 h, calvariae and tibiae were harvested for TEM. S. aureus cells were found in approximately 14% of the calvarial osteoblasts after subcutaneous injection and in 11% of calvarial and tibial osteoblasts following intraallantoic injection. Endosomes were observed in some cells, but most bacteria internalized appeared to be free in the cytoplasm. Osteoblasts with as few as five bacteria had a greater loss of cytoplasmic integrity and a more heterochromatic nucleus than osteoblasts with fewer bacteria or than uninfected osteoblasts. S. aureus cells in calvariae and tibiae were also observed in the cytoplasm of approximately 4% of the osteocytes in mineralized bone matrix. Thus, internalization of S. aureus by osteoblasts in vivo augments the previous observation in vitro. This study has also shown that osteoblasts with few bacteria continue differentiating into osteocytes. Results of these experiments support the hypothesis that internalization of S. aureus by osteoblasts may play a role in the etiology of osteomyelitis.

Results from this laboratory have shown that bone metabolism is directly related to extracellular pH and that high concentrations of tobramycin released from impregnated polymethylmethacryrate (PMMA) beads hs pH-dependent toxic effects on bone. In the present study, beneficial effects of calcium hydroxide-impregnated PMMA were investigated regarding tobramycin toxicity and bone metabolism in chick embryo tibiae in vitro. Also using Ca(OH) 2 as a pH regulator, the antibiotic efficacy of tobramycin-impregnated PMMA was evaluated with respect to inhibition of Staphylococcus aureus growth. When Ca(OH) 2 was added to PMMA beads containing tobramycin, the beads released hydroxyl and calcium ions into the culture medium and released more antibiotic than beads containing only tobramycin. Bone metabolism (glycolysis, total protein synthesis, and collagen synthesis) was enhanced by Ca(OH) 2 -impregnated beads with or without tobramycin. Additionally, bacterial growth was inhibited more strongly when S. aureus was incubated with tobramycin- and Ca(OH) 2 -impregnated PMMA disks than with disks containing only tobramycin. This study demonstrates the feasibility of adding Ca(OH) 2 to tobramycin-impregnated PMMA beads as a regulator of local pH and a promoter of bone metabolism for protection of bone when high concentrations of tobramycin are used to treat osteomyelitis. It also suggests that lower concentrations of antibiotic may be effective if Ca(OH) 2 and tobramycin are administered simultaneously.

A fluoride-resistant Streptococcus mutans isolate NCH105 was characterized and compared with wild-type strain UA130. The growth and lactic acid production of strain NCH105 were found to be unaffected by the presence of fluoride at the initial medium pH values of 6.5 and 6. In addition, NCH105 was found to be capable of lowering the pH of the medium to approximately 5.5, which is the critical level where enamel demineralization begins in vivo. Lactic acid production, glucose uptake at pH 6.5 and 6, as well as ATPase activity at pH 5 were found to be unaffected by fluoride. Finally, strain NCH105 is capable of binding as well as the wild-type bacterium to artificial tooth pellicles. These results are unusual when compared with previously isolated fluoride-resistant mutants and suggest that NCH105 may have the ability to colonize the tooth surface and initiate dental caries.

Staphylococcus aureus is the most common cause of both acute and chronic osteomyelitis; however, the pathogenesis of osteomyelitis is poorly understood. We investigated the ability of S. aureus to associate with chick osteoblasts in culture and have demonstrated internalization of bacteria by the osteoblasts. Two strains of S. aureus were examined that were ingested by osteoblasts to different extents, suggesting strain differences in uptake. Initial association of S. aureus strains with osteoblasts was independent of the presence of matrix collagen produced by the osteoblasts. Internalization of bacteria required live osteoblasts, but not live S. aureus, indicating osteoblasts are active in ingesting the organisms. The bacteria were not killed by the osteoblasts, since viable bacteria were cultured several hours after ingestion.

The so-called “Arab Spring” has accentuated the longstanding structural contradictions in US Middle East policy.’ It has created strains in US relations with Saudi Arabia, thus affecting a fundamental US interest in Middle East oil. It has exposed the paralysis in US policy on the Palestine question owing to the new influence of popular opinion on Arab governments combined with the intransigence of a right-wing Israeli government that continues to effectively dominate American policy through its influence on the US Congress and American public opinion. Meanwhile, despite recent US successes in the “war on terrorism,” aggressive American military tactics have deepened public hostility toward the US in Arab and Muslim opinion.

It is now commonplace to suggest that the collapse of the Soviet Union as a superpower has profoundly changed the international system. Analysts of the realist persuasion are already speculating about what the structural change from bipolarity to something else-be it monopolarity or mutipolarity-will mean. How will it affect the security perceptions, policies and behaviour of the major actors? Is President Bush's US dominated 'New World Order' likely to be more stable, more integrated, more prosperous, and less tense and dangerous than the old Cold War order? Initial US euphoria has been dissipated by the enormity of adjustment problems in the former Soviet bloc as well as by growing concern about the long-term capabilities of the USA itself. The answers are far from clear. Students of Middle East politics are also asking with growing apprehension how the New World Order will affect this troubled region. The 'cradle of civilisation' has been a 'cradle of conflict' for the past half-century. In 1990-91 the Middle East was the site of the first significant manifestation of Washington's bid for unchallenged world hegemony when President Bush assembled a formidable international coalition, joined by the USSR as a junior partner, to punish Iraq for its invasion of Kuwait. What will be the long-term effects of this unprecedented US intervention in the international politics of the region? What will the US-led New World Order in the Middle East be like? Is it really new? And how orderly will it be? How one answers these questions depends on what one takes to be 'objective realities' in the region and also on the analytic perspective employed. The first part of this essay reviews the Middle East regional situation after the Gulf War. The second part develops a typology of four scenarios of regional prospects, each argued in terms of two broad and widely utilised analytical approaches: the sociological approach, which sees actors' foreign policy behaviour mainly as the result of domestic factors, and the neorealist approach which explains international behaviour in terms of the security calculations of presumably rational, informed state actors. In the third part I make an argument as to which of the four scenarios might be the more plausible, in light of the configuration of domestic and international factors, and discuss some implications for the US position in the region.

Staphylococcus aureus is the principal etiological agent of osteomyelitis (bone infection), which is characterized by a progressive inflammatory response resulting in extensive damage to bone tissue. Recent studies have demonstrated the ability of S. aureus to invade and persist inside osteoblasts (bone matrix-forming cells) and other eukaryotic cells. The presence of intracellular S. aureus in bone tissue may be relevant to the pathology of osteomyelitis, a disease often refractory to antibiotic treatment and subject to recurrence months and even years after apparently successful therapy. The present study examined the production of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) following S. aureus infection, and whether expression of the molecule was induced by those osteoblasts containing intracellular S. aureus. Results from this study suggest that osteoblasts containing intracellular S. aureus induce TRAIL expression in uninfected osteoblasts present in infected cultures.

Antibiotic-encapsulated PLA and PLGA nanoparticles were prepared by the single emulsion-solvent evaporation technique. Different PLA and PLGA systems were prepared, varying the copolymer composition and the amount of the surfactant polyvinyl alcohol. Characterization and drug loading studies were performed by UV-Visible spectrophotometry, dynamic light scattering, and scanning electron microscopy (SEM).Simultaneously, in order to model the diffusion of the nanoparticles within the osteoblast, QDs such as functionalized InGaP/ZnS and polymer encapsulated InGaP/ZnS nanoparticles were added to confluent cultures of primary mouse osteoblasts. Following PreFer fixation, cultures were examined via confocal microscopy. QDs were clearly visible within osteoblasts.

Staphylococcus aureus is responsible for 80% of human osteomyelitis. It can invade and persist within osteoblasts. Antibiotic resistant strains of S. aureus make successful treatment of osteomyelitis difficult. Null Hypothesis: antibiotic sensitivities of S. aureus do not change after exposure to the osteoblast intracellular environment. Human and mouse osteoblast cultures were infected and S. aureus cells were allowed to invade. Following times 0, 12, 24, and 48 h ( ± the addition of erythromycin, clindamycin, and rifampin at times 0 or 12 h), the osteoblasts were lysed and intracellular bacteria enumerated. Transmission electron microscopy was performed on extracellular and intracellular S. aureus cells. In mouse osteoblasts, administration of bacteriostatic antibiotics at time 0 prevented the increase in intracellular S. aureus. If the antibiotics were delayed 12 h, this did not occur. When rifampin (bactericidal) was introduced at time 0 to human and mouse osteoblasts, there was a significant decrease in number of intracellular S. aureus within osteoblasts compared to control. If rifampin was delayed 12 h, this did not occur. Significant time-dependent S. aureus structural changes were observed after exposure to the osteoblast intracellular environment. These studies demonstrate that once S. aureus is established intracellularly for 12 h, the bacteria are less sensitive to antibiotics capable of eukaryotic cell penetration (statistically significant). These antibiotic sensitivity changes could be due in part to the observed structural changes. This leads to the rejection of our null hypotheses that the antibiotic sensitivities of S. aureus are unaltered by their location. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

In vivo expression of the virulence-associated fructosyltransferase gene (ftf) of Streptococcus mutans has been examined. S. mutans ftf expression is affected by both the specific carbohydrate consumed and the age of the host animal.

Background Staphylococcus aureus infection of normal osteoblasts induces expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Results Normal osteoblasts were incubated in the presence of purified bacterial products over a range of concentrations. Results demonstrate that purified surface structures and a selected superantigen present in the extracellular environment are not capable of inducing TRAIL expression by osteoblasts. Osteoblasts were co-cultured with S. aureus at various multiplicities of infection utilizing cell culture chamber inserts. Results of those experiments suggest that direct contact between bacteria and osteoblasts is necessary for optimal TRAIL induction. Finally, S. aureus infection of osteoblasts in the presence of anti-TRAIL antibody demonstrates that TRAIL mediates caspase-8 activation and apoptosis of infected cells. Conclusions Collectively, these findings suggest a mechanism whereby S. aureus mediates bone destruction via induction of osteoblast apoptosis.

Vibrio vulnificus is a pathogenic, estuarine bacterium associated with primary septicemia and severe wound infections. Previous studies have reported limited success in the introduction of plasmids intoV. vulnificus by conjugation, and there have been no reports of successful electroporation procedures. We report here on the introduction of recombinant plasmids into four strains ofV. vulnificus by electroporation. In contrast to the complex medium that others have used for the electroporation ofVibrio cholerae, the efficiency of transformation ofV. vulnificus was greatly improved by the use of a defined growth medium containing glucose. The addition of glycine betaine further enhanced transformant yield.

Staphylococcus aureusinvades osteoblasts and can persist in the intracellular environment. The present study examined the role of osteoblast mitogen-activated protein kinase (MAPK) pathways in bacterial invasion.S. aureusinfection of normal human and mouse osteoblasts resulted in an increase in the phosphorylation of the extracellular signal-regulated protein kinases (ERK 1 and 2). This stimulation of ERK 1 and 2 correlated with the time course ofS. aureusinvasion, and bacterial adherence induced the MAPK pathway. ERK 1 and 2 phosphorylation was time and dose dependent and required activeS. aureusgene expression for maximal induction. The nonpathogenicStaphylococcus carnosuswas also able to induce ERK 1 and 2 phosphorylation, albeit at lower levels thanS. aureus. Phosphorylation of the stress-activated protein kinases was increased in both infected human and mouse osteoblasts; however, the p38 MAPK pathway was not activated in response toS. aureus. Finally, the transcription factor c-Jun, but not Elk-1 or ATF-2, was phosphorylated in response toS. aureusinfection.

Staphylococcus aureusandSalmonella entericaserovar Dublin invade osteoblasts and are causative agents of human bone disease. In the present study, we examined the ability ofS. aureusandSalmonellaserovar Dublin to induce the production of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) by normal osteoblasts. Normal mouse and human osteoblasts were cocultured withS. aureusorSalmonellaserovar Dublin at different multiplicities of infection. Following initial incubation and examination of TRAIL expression, extracellular bacteria were killed by the addition of media containing the antibiotic gentamicin. Lysates and conditioned media from osteoblast cultures were then collected at various times following invasion and analyzed. The results demonstrated thatS. aureusandSalmonellaserovar Dublin are potent inducers of TRAIL expression by osteoblasts. Mouse and human TRAIL mRNA expression was induced by bacterial infection and demonstrated a dose-dependent response. Analysis of kinetics suggested that TRAIL mRNA was induced within 30 min after exposure to bacteria and that its level of expression remained relatively constant over the time period examined. mRNA molecules encoding TRAIL receptors were constitutively expressed by osteoblasts. Furthermore, TRAIL protein was detected as early as 45 min and up to 24 h following infection. The quantity of TRAIL protein produced also increased in a dose-dependent manner. Collectively, these findings suggest a mechanism whereby bacterial pathogens mediate bone destruction via osteoblast apoptosis.

Staphylococcus aureusandSalmonellaspp. are common causes of bone diseases; however, the immune response during such infections is not well understood. Colony-stimulating factors (CSF) have a profound influence on osteoclastogenesis, as well as the development of immune responses following infection. Therefore, we questioned whether interaction of osteoblasts with two very different bacterial pathogens could affect CSF expression by these cells. Cultured mouse and human osteoblasts were exposed to various numbers ofS. aureusorSalmonella dublinbacteria, and a comprehensive analysis of granulocyte-macrophage (GM)-CSF, granulocyte (G)-CSF, macrophage (M)-CSF, and interleukin-3 (IL-3) mRNA expression and cytokine secretion was performed. Expression of M-CSF and IL-3 mRNAs by mouse osteoblasts was constitutive and did not increase significantly following bacterial exposure. In contrast, GM-CSF and G-CSF mRNA expression by mouse osteoblasts was dramatically upregulated following interaction with either viableS. aureusorSalmonella. This increased mRNA expression also translated into high levels of GM-CSF and G-CSF secretion by mouse and human osteoblasts following bacterial exposure. ViableS. aureusandSalmonellainduced maximal levels of CSF mRNA expression and cytokine secretion compared to UV-killed bacteria. Furthermore, GM-CSF and G-CSF mRNA expression could be induced in unexposed osteoblasts separated by a permeable Transwell membrane from bacterially exposed osteoblasts. M-CSF secretion was increased in cultures of exposed human osteoblasts but not in exposed mouse osteoblast cultures. Together, these studies are the first to define CSF expression and suggest that, following bacterial exposure, osteoblasts may influence osteoclastogenesis, as well as the development of an immune response, via the production of these cytokines.