Synthesis, characterization and biological evaluation of a new photoactive hydrogel against Gram-positive and Gram-negative bacteria

In 2013, the World Health Organization reported that 884 million people lack access to clean potable water. Photodynamic antimicrobial chemotherapy (PACT) is a very promising alternative to conventional antibiotics for the efficient inactivation of pathogenic microorganisms. We report the synthesis, characterization and antibacterial activity of a polyacrylamide-based hydrogel (7), with a new photoactive phenothiazinium compound (6) immobilized on it, to be used as a novel water-sterilizing device. The hydrogel was characterized by IR and scanning electron microscopy and incorporation of the dye confirmed by UV-visible spectroscopy. Antibacterial tests using the recombinant bioluminescent Gram-positive Staphylococcus aureus RN4220 and Gram-negative Escherichia coli DH5α were performed to assess the ability of the hydrogel to inactivate bacterial strains in solution. The hydrogel is characterized by a non-ordered microporous structure and is able to generate reactive oxygen species. The hydrogel is able to inactivate planktonic cells of the S. aureus and E. coli (3.3 log and 2.3 log killing, respectively) after 25 min of irradiation with white light at 14.5 mW cm−2. The contact surface does not influence the kill rates while the killing rate increased by increasing the total amount of the hydrogel (0.27 log drop to 1.65 log drop with 0.5 mg cm−3 to 2.5 mg cm−3 of total amount of dye). The hydrogel was found to be active for four cycles, suggesting the possibility of reuse and it was shown to be active against both Gram-positive and Gram-negative species with no leaching of the active molecule

Duramycin-porphyrin conjugates for targeting of tumour cells using photodynamic therapy

Duramycin, through binding with phosphatidylethanolamine (PE), has been shown to be a selective molecular probe for the targeting and imaging of cancer cells. Photodynamic therapy aims to bring about specific cytotoxic damage to tumours through delivery of a photosensitising agent and light irradiation. Conjugation to biological molecules that specifically target cancer has been shown to increase photosensitiser (PS) selectivity and decrease damage to surrounding normal tissue. The aim of this study was to target tumour cells with a PE-specific PS therefore duramycin was conjugated to a porphyrin based PS which was achieved via direct reaction with the ε-amino group on the lysine residue near duramycin's N-terminal. The compound was subsequently purified using RP-HPLC and confirmed using mass spectrometry. Binding of the conjugate to ovarian and pancreatic cancer cell lines was assessed by flow cytometry. Light irradiation with a light fluence of 7.5 J/cm2 was delivered to conjugate treated cancer cells and cell proliferation analysed by MTT assay. The conjugate detected PE on all 4 cancer cell lines in a concentration dependent manner and conjugate plus irradiation effectively reduced cell proliferation at concentrations ≥0.5 μM, dependent on cancer cell line. Reduction in cell proliferation by the irradiated conjugate was enhanced over unconjugated duramycin in A2780, AsPC-1 and SK-OV-3 (p b 0.05). In this study we have shown that a duramycin-porphyrin conjugate retained good binding affinity for its target and, following irradiation, reduced cell proliferation of pancreatic and ovarian cancer cell lines

Photoinduced Photosensitizer-Antibody Conjugates Kill HIV Env-Expressing Cells, Also Inactivating HIV.

HIV-infected cells persist for decades in patients administered with antiretroviral therapy (ART). Meanwhile, an alarming surge in drug-resistant HIV viruses has been occurring. Addressing these issues, we propose the application of photoimmunotherapy (PIT) against not only HIV Env-expressing cells but also HIV. Previously, we showed that a human anti-gp41 antibody (7B2) conjugated to cationic or anionic photosensitizers (PSs) could specifically target and kill the HIV Env-expressing cells. Here, our photolysis studies revealed that the binding of photoimmunoconjugates (PICs) on the membrane of HIV Env-expressing cells is sufficient to induce necrotic cell death due to physical damage to the membrane by singlet oxygen, which is independent of the type of PSs. This finding persuaded us to study the virus photoinactivation of PICs using two HIV-1 strains, X4 HIV-1 NL4-3 and JR-CSF virus. We observed that the PICs could destroy the viral strains, probably via physical damage on the HIV envelope. In conclusion, we report the application of PIT as a possible dual-tool for HIV immunotherapy and ART by killing HIV-expressing cells and cell-free HIV, respectively

He Scores Through a Screen: Mediating Masculinities Through Hockey Video Games

Hockey video games highlight the ways in which the video game medium shapes and conditions the experience of producing and/or performing the sport “in real life.” Indeed, the accumulation of advanced statistics in and through the constant evaluation, measurement, and surveillance which are inherent to video games—and increasingly seen as foundational for sport—reveals important contradictions not only in the way the embodied sport is played and understood, but also in terms of the proofs of masculinity upon which the sport is built. It then becomes clear that the building of masculinity and the empowerment of the character become one and the same. The ludic function reinforces the cultural imperative and vice versa. Thus, our chapter prizes apart the conflation of masculinity with hockey while showing the ways that video game studies can contribute to existing disciplines

Integration of decision support systems to improve decision support performance

Decision support system (DSS) is a well-established research and development area. Traditional isolated, stand-alone DSS has been recently facing new challenges. In order to improve the performance of DSS to meet the challenges, research has been actively carried out to develop integrated decision support systems (IDSS). This paper reviews the current research efforts with regard to the development of IDSS. The focus of the paper is on the integration aspect for IDSS through multiple perspectives, and the technologies that support this integration. More than 100 papers and software systems are discussed. Current research efforts and the development status of IDSS are explained, compared and classified. In addition, future trends and challenges in integration are outlined. The paper concludes that by addressing integration, better support will be provided to decision makers, with the expectation of both better decisions and improved decision making processes

Investigating Childhood Leukemia in Churchill County, Nevada

BACKGROUND: Sixteen children diagnosed with acute leukemia between 1997 and 2002 lived in Churchill County, Nevada, at the time of or before their illness. Considering the county population and statewide cancer rate, fewer than two cases would be expected. OBJECTIVES: In March 2001, the Centers for Disease Control and Prevention led federal, state, and local agencies in a cross-sectional, case-comparison study to determine if ongoing environmental exposures posed a health risk to residents and to compare levels of contaminants in environmental and biologic samples collected from participating families. METHODS: Surveys with more than 500 variables were administered to 205 people in 69 families. Blood, urine, and cheek cell samples were collected and analyzed for 139 chemicals, eight viral markers, and several genetic polymorphisms. Air, water, soil, and dust samples were collected from almost 80 homes to measure more than 200 chemicals. RESULTS: The scope of this cancer cluster investigation exceeded any previous study of pediatric leukemia. Nonetheless, no exposure consistent with leukemia risk was identified. Overall, tungsten and arsenic levels in urine and water samples were significantly higher than national comparison values; however, levels were similar among case and comparison groups. CONCLUSIONS: Although the cases in this cancer cluster may in fact have a common etiology, their small number and the length of time between diagnosis and our exposure assessment lessen the ability to find an association between leukemia and environmental exposures. Given the limitations of individual cancer cluster investigations, it may prove more efficient to pool laboratory and questionnaire data from similar leukemia clusters

The development and characterisation of porphyrin isothiocyanate–monoclonal antibody conjugates for photoimmunotherapy

A promising approach to increase the specificity of photosensitisers used in photodynamic therapy has been through conjugation to monoclonal antibodies (MAb) directed against tumour-associated antigens. Many of the conjugations performed to date have relied on the activated ester method, which can lead to impure conjugate preparations and antibody crosslinking. Here, we report the development of photosensitiser–MAb conjugates utilising two porphyrin isothiocyanates. The presence of a single reactive isothiocyanate allowed facile conjugation to MAb FSP 77 and 17.1A directed against internalising antigens, and MAb 35A7 that binds to a non-internalising antigen. The photosensitiser–MAb conjugates substituted with 1–3 mol of photosensitiser were characterised in vitro. No appreciable loss of immunoreactivity was observed and binding specificity was comparable to that of the unconjugated MAb. Substitution with photosensitiser had a minimal effect on antibody biodistribution in vivo for the majority of the conjugates, although a decreased serum half-life was observed using a cationic photosensitiser at the higher loading ratios. Tumour-to-normal tissue ratios as high as 33.5 were observed using MAb 35A7 conjugates. The internalising conjugate showed a higher level of phototoxicity as compared with the non-internalising reagent, using a cell line engineered to express both target antigens. These data demonstrate the applicability of the isothiocyanate group for the development of high-quality conjugates, and the use of internalising MAb to significantly increase the photodynamic efficiency of conjugates during photoimmunotherapy

A Simple, Inexpensive Device for Nucleic Acid Amplification without Electricity—Toward Instrument-Free Molecular Diagnostics in Low-Resource Settings

Molecular assays targeted to nucleic acid (NA) markers are becoming increasingly important to medical diagnostics. However, these are typically confined to wealthy, developed countries; or, to the national reference laboratories of developing-world countries. There are many infectious diseases that are endemic in low-resource settings (LRS) where the lack of simple, instrument-free, NA diagnostic tests is a critical barrier to timely treatment. One of the primary barriers to the practicality and availability of NA assays in LRS has been the complexity and power requirements of polymerase chain reaction (PCR) instrumentation (another is sample preparation).In this article, we investigate the hypothesis that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays. We assess the heater's equivalence to commercially available PCR instruments through the characterization of the temperature profiles produced, and a minimal method comparison. Versions of the prototype for several different isothermal techniques are presented.We demonstrate that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays, and that the results of those assays are not significantly different from ones incubated in parallel in commercially available PCR instruments. These results clearly suggest the potential of the non-instrumented nucleic acid amplification (NINA) heater for molecular diagnostics in LRS. When combined with other innovations in development that eliminate power requirements for sample preparation, cold reagent storage, and readout, the NINA heater will comprise part of a kit that should enable electricity-free NA testing for many important analytes

Where's all the 'good' sports journalism? Sports media research, the sociology of sport, and the question of quality sports reporting

Across newsrooms and journalism schools, questions as to what constitutes or ‘counts’ as excellent reporting are currently inciting much debate. Among the various frameworks being put forward to describe and encourage ‘excellent’ journalism in its various forms, sport is seldom mentioned – a legacy perhaps of its perennial dismissal as trivial subject matter. This essay grew from our curiosity as to whether the reverse was also true: that is, whether and what those who study sports journalism and sports media – in particular sociologists of sport – have contributed to understandings of ‘best’ and even excellent journalistic practice. We identified and analysed 376 articles from eight leading scholarly journals that feature sports media research with the aim of examining instances where ‘excellent’ sports reporting was either highlighted, described or advocated. After outlining the major themes that emerged from this analysis, we reflect on why so few of the sampled articles explicitly advise on what best practice sports journalism might look like – especially when it comes to coverage of the sport-related social issues that sociologists of sport tend to focus on – and why so little theoretical attention has been afforded to the question of excellent sports journalism more generally. While there are good sociological reasons for focusing on problematic sports reporting, on structural and systemic issues in which media are implicated, and on producing alternatives to hegemonic sports media, we conclude that it is high time for instances of excellent sports journalism to be afforded the theoretical and empirical attention long granted to their ‘bad’ journalistic counterparts