Protease-activated receptors: protease signaling in the gastrointestinal tract

Serine proteases from the circulation, inflammatory cells, digestive glands and microorganisms can signal to cells by cleaving protease-activated receptors (PARs), a family of four G-protein-coupled receptors. Proteases cleave PARs at specific sites to expose tethered ligand domains that bind to and activate the cleaved receptors. Despite this irreversible mechanism of activation, PAR signaling is tightly regulated to prevent the uncontrolled stimulation of cells. Although PARs are found in all organ systems, protease signaling is of particular interest in the gastrointestinal tract, where proteases regulate neurotransmission, secretion, motility, epithelial permeability and intestinal inflammation, and can thus contribute to disease.

Effects of single- and multi-strain probiotics on biofilm formation and in vitro adhesion to bladder cells by urinary tract pathogens

Inhibition of biofilm seems to be a major mechanism of urinary tract pathogen exclusion, related to, and possibly dependent upon, the probiotic ability to reduce environmental pH. Exclusion via competition of binding sites is a possible in vivo mechanism for these probiotics. If an additive or synergistic effect exists between strains within a mixture, it does not manifest itself in a greater effect through these two inhibitory mechanisms.

Comparative analysis of intestinal tract models

The human gut is a complex ecosystem occupied by a diverse microbial community. Modulation of this microbiota impacts health and disease. The definitive way to investigate the impact of dietary intervention on the gut microbiota is a human trial. However, human trials are expensive and can be difficult to control; thus, initial screening is desirable. Utilization of a range of in vitro and in vivo models means that useful information can be gathered prior to the necessity for human intervention. This review discusses the benefits and limitations of these approaches.

Adherence and invasion of Bacteroidales isolated from the human intestinal tract

Members of the genera Bacteroides and Parabacteroides are important constituents of both human and animal intestinal microbiota, and are significant facultative pathogens. In this study, the ability of Bacteroides spp. and Parabacteroides distasonis isolated from both diarrhoeal and normal stools (n = 114) to adhere to and invade HEp-2 cells was evaluated. The presence of putative virulence factors such as capsule and fimbriae was also investigated. Adherence to HEp-2 cells was observed in 75.4% of the strains, which displayed non-localized clusters. Invasion was observed in 37.5% and 26% of the strains isolated from diarrhoeal and non-diarrhoeal stools, respectively. All strains displayed a capsule, whereas none of them showed fimbriae-like structures. This is the first report of the ability of Bacteroides spp. and P. distasonis to adhere to and invade cultured HEp-2 epithelial cells.

A reputation-based trust model for agent societies

Trust and security issues are prevalent in agent societies, where agents are autonomously owned and operated in a networked environment. Nowadays, trust and reputation management is a promising approach to manage them. However, many reputation models su.ered from a major drawback – there is no mechanism to discourage agents from lying information when making a recommendation. Although some works do take into account of this issue, they usually do not penalize an agent for making poor referrals. Worse, some systems actually judge an agents referral reputation based on its service reputation. In situations where this is unacceptable, we need to have a mechanism where agents are not only discouraged from making poor referrals, but are also penalized when doing so. Towards this, we propose a reputation-based trust model that considers an agents referral reputation as a separate entity within the broader sense of an agents reputation. Our objective is not to replace any existing reputation mechanisms, but rather to complement and extend them.

Does successful treatment of constipation or faecal impaction resolve lower urinary tract symptoms? A structured review of the literature

Consensus guidelines advocate the treatment of constipation and faecal impaction in order to improve symptoms of urinary frequency, urgency and urinary incontinence and to promote bladder emptying in the absence of urinary tract obstruction. This structured review of the literature was undertaken to search for and appraise evidence to support or negate the hypothesis of this relationship. The search strategy was comprehensive and identified six relevant studies. Two of these had been conducted on an adult population and four studies involved children with constipation. These studies were appraised for methodological quality. It was found that sample sizes were small and evidence was inconsistent. Variable methods of reporting meant that data were not able to be pooled for meta-analysis.
Based on the limited and conflicting evidence, it is recommended that further research be undertaken to identify any correlation between bowel and bladder function.

Water-binding capacity and viscosity of Australian sweet lupin kernel fibre under in vitro conditions simulating the human upper gastrointestinal tract

There is currently little understanding of the physicochemical properties in the human gastrointestinal tract of Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKF), a novel food ingredient with potential for the fibre enrichment of foods such as baked goods. Since physicochemical properties of dietary fibres have been related to beneficial physiological effects in vitro, this study compared water-binding capacity and viscosity of LKF with that of other fibres currently used for fibre-enrichment of baked goods, under in vitro conditions simulating the human upper gastrointestinal tract. At between 8.47 and 11.07g water/g dry solids, LKF exhibited water-binding capacities that were significantly higher (P<0.05) than soy fibre, pea hull fibre, cellulose and wheat fibre at all of the simulated gastrointestinal stages examined. Similarly, viscosity of LKF was significantly higher (P<0.05) than that of the other fibres at all simulated gastrointestinal stages. The relatively high water-binding capacity and viscosity of LKF identified in this study suggests that this novel fibre ingredient may elicit different and possibly more beneficial physiological effects in the upper human gastrointestinal tract than the conventional fibre ingredients currently used in fibre-enriched baked goods manufacture. We are now performing human studies to investigate the effect of LKF in the diet on health-related gastrointestinal events.

Identity in multicultural societies: who do we think we are?

This paper examines identity issues in multicultural Australia. In its extreme, negative form, assumptions that certain characteristics apply to all members of an ethnic group can be attributed to racism. However, the belief that individuals who share the same ethnic background have similar needs, interests and perceptions is also reflected in business, government policy and academic research. Often, ethnic groupings used for research and policy formulation are very broad and fail to take into account within-group differences. The criteria used to assess an individuals membership of an ethnic group can be problematic. Criteria based purely on objective measures such as country of birth or ethnic ancestry do not take into account acculturation processes or the degree to which individuals consider themselves to be 'ethnic '. These objective measures are complicated further as individuals may have ethnic roots from multiple countries depending on their family composition over several generations. This theory-focused paper proposes that ethnic identity should be viewed as a subjective phenomenon where individuals are likely to align themselves with the ethnic background to which they most identify. This has implications for research and policy making in multicultural societies.

Arts marketing challenges in multicultural societies

With an increasingly diverse, multicultural society in many countries, it is timely to look more closely at the current literature on arts marketing, ethnic identity and segmentation issues. The growth of diverse, multicultural societies in many countries warrants a closer examination of arts marketing and the use of ethnicity as a basis for segmentation, as these issues have implications for attracting and retaining arts audiences and other consumers of arts related activities. Researchers in the arts industry have stressed the importance of understanding the fundamentals of audience development and the ability to focus on satisfying the needs and wants of their audiences. The focus on marketing activities comes at a time when there is greater pressure on arts organisations to move beyond their traditional role as subsidized non-profit organisations in order to become more self-supporting. Internationally, audience development in the arts industry has focused on segmentation dimensions such as youth, mature aged individuals, geographic location (rural), individuals with disabilities, low income earners, and individuals with culturally diverse backgrounds. Most of these potential segments are under represented in the population of arts consumers in Australia, the United Kingdom, Singapore, and North America. Of those dimensions, segmentation of arts markets by cultural differences such as ethnic identity appears to be a somewhat under researched area. Hofstede's (1980) model of national cultural differences continues to be widely used as a basis for strategic and marketing decisions in international business. However, the cultural characteristics attributed to individuals in their country of birth are likely to change through immigration to another country. In this situation, the ability to predict the consumption behaviour of various ethnic groups is complicated by acculturation processes in which arrivals attempt to adapt to their new environment. Over time, this process has resulted in the emergence of bicultural individuals who are able to switch, at will, between their ethnic identity and an identity aligned with their host country, or a combination of both at any time. Ethnic identity and affiliation with ethnic groups can also change over time, suggesting challenges for arts marketing approaches, and the application of market segmentation theory in particular.