Low-income consumers' attitudes and behaviour towards access, availability and motivation to eat fruit and vegetables

To determine low-income consumers' attitudes and behaviour towards fruit and vegetables, in particular issues of access to, affordability of and motivation to eat fruit and vegetables. Design and setting: Questionnaire survey mailed to homes owned by a large UK housing association. Participants: Participants were 680 low-income men and women, aged 17-100 years. Results: Age, employment, gender, smoking and marital status all affected attitudes towards access, affordability and motivation to eat fruit and vegetables. Few (7%) participants experienced difficulty in visiting a supermarket at least once a week, despite nearly half having no access to a car for shopping. Fruit and vegetables were affordable to this low-income group in the amounts they habitually bought; purchasing additional fruits and vegetables was seen as prohibitively expensive. Less than 5% felt they had a problem with eating healthily and yet only 18% claimed to eat the recommended 5 or more portions of fruit and vegetables every day. Conclusions: Supported by research, current UK Government policy is driven by the belief that low-income groups have difficulties in access to and affordability of fruit and vegetables. Findings from this particular group suggest that, of the three potential barriers, access and affordability were only a small part of the 'problem' surrounding low fruit and vegetable consumption. Thus, other possible determinants of greater consequence need to be identified. We suggest focusing attention on motivation to eat fruit and vegetables, since no dietary improvement can be achieved if people do not recognise there is a problem

RNA interference approaches for treatment of HIV-1 infection

HIV/AIDS is a chronic and debilitating disease that cannot be cured with current antiretroviral drugs. While combinatorial antiretroviral therapy (cART) can potently suppress HIV-1 replication and delay the onset of AIDS, viral mutagenesis often leads to viral escape from multiple drugs. In addition to the pharmacological agents that comprise cART drug cocktails, new biological therapeutics are reaching the clinic. These include gene-based therapies that utilize RNA interference (RNAi) to silence the expression of viral or host mRNA targets that are required for HIV-1 infection and/or replication. RNAi allows sequence-specific design to compensate for viral mutants and natural variants, thereby drastically expanding the number of therapeutic targets beyond the capabilities of cART. Recent advances in clinical and preclinical studies have demonstrated the promise of RNAi therapeutics, reinforcing the concept that RNAi-based agents might offer a safe, effective, and more durable approach for the treatment of HIV/AIDS. Nevertheless, there are challenges that must be overcome in order for RNAi therapeutics to reach their clinical potential. These include the refinement of strategies for delivery and to reduce the risk of mutational escape. In this review, we provide an overview of RNAi-based therapies for HIV-1, examine a variety of combinatorial RNAi strategies, and discuss approaches for ex vivo delivery and in vivo delivery

Disruption of Lateral Efferent Pathways: Functional Changes in Auditory Evoked Responses

The functional consequences of selectively lesioning the lateral olivocochlear efferent system in guinea pigs were studied. The lateral superior olive (LSO) contains the cell bodies of lateral olivocochlear neurons. Melittin, a cytotoxic chemical, was injected into the brain stem using stereotaxic coordinates and near-field evoked potentials to target the LSO. Brain stem histology revealed discrete damage to the LSO following the injections. Functional consequences of this damage were reflected in depressed amplitude of the compound action potential of the eighth nerve (CAP) following the lesion. Threshold sensitivity and N1 latencies were relatively unchanged. Onset adaptation of the cubic distortion product otoacoustic emission (DPOAE) was evident, suggesting a reasonably intact medial efferent system. The present results provide the first report of functional changes induced by isolated manipulation of the lateral efferent pathway. They also confirm the suggestion that changes in single-unit auditory nerve activity after cutting the olivocochlear bundle are probably a consequence of disrupting the more lateral of the two olivocochlear efferent pathways.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41379/1/10162_2002_Article_3018.pd

ATP-Evoked Intracellular Ca Signaling of Different Supporting Cells in the Hearing Mouse Hemicochlea

Hearing and its protection is regulated by ATP-evoked Ca2+ signaling in the supporting cells of the organ of Corti, however, the unique anatomy of the cochlea hampers observing these mechanisms. For the first time, we have performed functional ratiometric Ca2+ imaging (fura-2) in three different supporting cell types in the hemicochlea preparation of hearing mice to measure purinergic receptor-mediated Ca2+ signaling in pillar, Deiters' and Hensen's cells. Their resting [Ca2+]i was determined and compared in the same type of preparation. ATP evoked reversible, repeatable and dose-dependent Ca2+ transients in all three cell types, showing desensitization. Inhibiting the Ca2+ signaling of the ionotropic P2X (omission of extracellular Ca2+) and metabotropic P2Y purinergic receptors (depletion of intracellular Ca2+ stores) revealed the involvement of both receptor types. Detection of P2X2,3,4,6,7 and P2Y1,2,6,12,14 receptor mRNAs by RT-PCR supported this finding and antagonism by PPADS suggested different functional purinergic receptor population in pillar versus Deiters' and Hensen's cells. The sum of the extra- and intracellular Ca2+-dependent components of the response was about equal with the control ATP response (linear additivity) in pillar cells, and showed supralinearity in Deiters' and Hensen's cells. Calcium-induced calcium release might explain this synergistic interaction. The more pronounced Ca2+ leak from the endoplasmic reticulum in Deiters' and Hensen's cells, unmasked by cyclopiazonic acid, may also suggests the higher activity of the internal stores in Ca2+ signaling in these cells. Differences in Ca2+ homeostasis and ATP-induced Ca2+ signaling might reflect the distinct roles these cells play in cochlear function and pathophysiology

Patterning, predicting stream macroinvertebrate assemblages in Victoria (Australia) using artificial neural networks and genetic algorithms

Macroinvertebrate assemblages are widely used for biomonitoring of stream ecosystems. Several modern assessment concepts and approaches have been desribed. The so-called referential approach (Parsons and Norris 1996, Marchant et al. 1999, Smith et al. 1999) is based on the comparison of macroinvertebrate communities between potentially impacted sites and reference sites considered to be pristine. Knowing the relationships between environmental variables and macroinvertebrate occurrence at reference sites, it is possible to predict species or taxa, which should occur at the remaining sites in the absence of anthropogenic stress. The ratio of observed/expected (O/E) families is used as a measure for sitespecific ecological conditions. Statistical and computational techniques have been successfully integrated into the referential approach facilitating stream site classification and prediction of macroinvertebrate assemblages. Classification or grouping of macroinvertebrates into assemblages is sometimes criticized as an arbitrary procedure as they are usually distributed in continuous gradients rather than well defined separate groups (Chessman 1999). However in order to deal with large numbers of macroinvertebrate taxa it is often crucial to consider groups instead of individual taxa provided appropriate classification techniques are available. Widely used statistical methods for data classification and ordination are cluster and principal component analysis. Both methods have shortcomings in coping with heterogeneous and nonlinear data, and results can be confounded by outliers and missing data. Artificial neural network (ANN) based classification techniques such as Kohonen or Self- Organizing Maps (SOM) may help to overcome these shortcomings. A number of ecological case studies have shown that SOM are an efficient classification tool (Chon et al. 1996, 2003, Cereghino et al. 2001, Park et al. 2001a, 2003a, Brosse et al. 2001, Giraudel and Lek 2001). ANN as well as genetic algorithms (GA) prove to be appropriate for the prediction of macroinvertebrate and fish assemblages in streams. Multi-layer perceptron ANN were successfully applied to predict the occurrence of stream macroinvertebrates from environmental variables (Walley and Fontama 1998, Schleiter et al. 1999, Pudmenzky et al. 1998, Hoang et al. 2001). GA were used to predict fish distribution from physical characteristics of streams (d'Angelo et al. 1995) and to select input variables of classification tree models predicting benthic macroinvertebrate communities in Belgian watercourses (Goethals et al. 2003). Even though ANN have clearly demonstrated their potential for ecological applications in terms of classification and prediction they store learned models in a highly distributed manner by means of connection weights, which bear little resemblance to human understanding of rules or concepts. By contrast, GA can be used for knowledge discovery by deriving predictive models or rule sets, which can easily be understood (Recknagel 2001). Recknagel et al. (2002) compared applications of ANN and GA in terms of forecasting and understanding of algal blooms in Lake Kasumigaura (Japan). It was demonstrated that models explicitly synthesized by GA not only performed better in seven-days-ahead predictions of algal blooms than ANN models, but provided more transparency for explanation as well. The present paper demonstrates the use of both ANN and GA for the classification and prediction of macroinvertebrate spatial assemblages in the stream system of Victoria (Australia). The stream database contains abundances of macroinvertebrates in conjunction with environmental and stream habitat characteristics. Both ANN and GA are applied in order to best compromise: (i) the discovery and explanation of patterns of macroinvertebrate occurrence within the Victorian landscape, and (ii) the prediction of these patterns from environmental variables. The predictive and explanatory performance of both ANN and GA will also be compared. © Springer-Verlag Berlin Heidelberg 2005

Gap junctional hemichannel-mediated ATP release and hearing controls in the inner ear

Connexin gap junctions play an important role in hearing function, but the mechanism by which this contribution occurs is unknown. Connexins in the cochlea are expressed only in supporting cells; no connexin expression occurs in auditory sensory hair cells. A gap junctional channel is formed by two hemichannels. Here, we show that connexin hemichannels in the cochlea can release ATP at levels that account for the submicromolar concentrations measured in the cochlear fluids in vivo. The release could be increased 3- to 5-fold by a reduction of extracellular Ca(2+) or an increase in membrane stress, and blocked by gap junctional blockers. We also demonstrated that extracellular ATP at submicromolar levels apparently affected outer hair cell (OHC) electromotility, which is an active cochlear amplifier determining cochlear sensitivity to sound stimulation in mammals. ATP reduced OHC electromotility and the slope factor of the voltage dependence and shifted the operating point to reduce the active amplifier gain. ATP also reduced the generation of distortion products. Immunofluorescent staining showed that purinergic receptors P2x2 and P2x7 were distributed on the OHC surface. Blockage of P2 receptors eliminated the effect of ATP on the OHC electromotility. The data revealed that there is a hemichannel-mediated, purinergic intercellular signaling pathway between supporting cells and hair cells in the cochlea to control hearing sensitivity. The data also demonstrated a potential source of ATP in the cochlea