485 research outputs found

    MULTI-UUV MISSIONS USING RANGER MicroUUVs

    Get PDF
    ABSTRACT Groups of four UUVs have been used to validate a plume source localization algorithm and map the 3-D movement of a salinity front over time. These missions have demonstrated that not only are multi-vehicle deployments possible, but by using teams of cooperating vehicles, difficult tasks such as plume source localization can be performed quickly and that small volumes of the ocean can be simultaneously sampled with unprecedented spatial and temporal resolution. The key to the success of these missions is the small, inexpensive and easy to operate Ranger MicroUUV from Nekton Research. We report on the results of recent multi-agent missions and provide information about the UUVs used during these missions

    Streptococcus agalactiae infects glial cells and invades the central nervous system via the olfactory and trigeminal nerves

    Get PDF
    Streptococcus agalactiae causes neonatal meningitis and can also infect the adult central nervous system (CNS). S. agalactiae can cross the blood-brain barrier but may also reach the CNS via other paths. Several species of bacteria can directly invade the CNS via the olfactory and trigeminal nerves, which extend between the nasal cavity and brain and injury to the nasal epithelium can increase the risk/severity of infection. Preterm birth is associated with increased risk of S. agalactiae infection and with nasogastric tube feeding. The tubes, also used in adults, can cause nasal injuries and may be contaminated with bacteria, including S. agalactiae. We here investigated whether S. agalactiae could invade the CNS after intranasal inoculation in mice. S. agalactiae rapidly infected the olfactory nerve and brain. Methimazole-mediated model of nasal epithelial injury led to increased bacterial load in these tissues, as well as trigeminal nerve infection. S. agalactiae infected and survived intracellularly in cultured olfactory/trigeminal nerve- and brain-derived glia, resulting in cytokine production, with some differences between glial types. Furthermore, a non-capsulated S. agalactiae was used to understand the role of capsule on glial cells interaction. Interestingly, we found that the S. agalactiae capsule significantly altered cytokine and chemokine responses and affected intracellular survival in trigeminal glia. In summary, this study shows that S. agalactiae can infect the CNS via the nose-to-brain path with increased load after epithelial injury, and that the bacteria can survive in glia

    Hepatitis B Sero-Prevalence and Risk Behaviors Among Immigrant Men in a Population-Based Household Survey in Low-Income Neighborhoods of Northern California

    Get PDF
    Background Despite an effective vaccine, 60,000 new HBV infections were reported in the US in 2004; 95% in adults. We evaluate HBV sero-prevalence, risk behaviors and self-reported vaccination among Latino immigrant, Asian immigrant and US born low income men in five northern California counties. Methods Population based, cross sectional survey of HBV sero-prevalence and risk behaviors in men aged 18 to 35 years. Results Among 1,512 men screened, Asian immigrants were most likely to have had prior HBV infection (15.1%) and chronic infection (3.8%) compared to US born (prior 5.1%, chronic 0.6%) and Latino immigrant men (prior 2.0%, chronic 0.3%.) Reported HBV vaccination was lowest for Latino immigrants (12%) compared to Asian immigrants and US born men (35% in both.) Latino immigrants reported less educational attainment, medical insurance coverage and access to a physician in the last six months. Discussion Healthcare providers should routinely screen Asian immigrants for HBV regardless of their self reported vaccination status. Latino immigrants may comprise an important group of under-vaccinated, at risk persons in California. HBV testing and vaccination of immigrants soon after US arrival should be encouraged

    A Small Genomic Region Containing Several Loci Required for Gastrulation in Drosophila

    Get PDF
    Genetic screens in Drosophila designed to search for loci involved in gastrulation have identified four regions of the genome that are required zygotically for the formation of the ventral furrow. For three of these, the genes responsible for the mutant phenotypes have been found. We now describe a genetic characterization of the fourth region, which encompasses the cytogenetic interval 24C3-25B, and the mapping of genes involved in gastrulation in this region. We have determined the precise breakpoints of several existing deficiencies and have generated new deficiencies. Our results show that the region contains at least three different loci associated with gastrulation effects. One maternal effect gene involved in ventral furrow formation maps at 24F but could not be identified. For a second maternal effect gene which is required for germ band extension, we identify a candidate gene, CG31660, which encodes a G protein coupled receptor. Finally, one gene acts zygotically in ventral furrow formation and we identify it as Traf4

    Calorie Restriction Increases Muscle Mitochondrial Biogenesis in Healthy Humans

    Get PDF
    BACKGROUND: Caloric restriction without malnutrition extends life span in a range of organisms including insects and mammals and lowers free radical production by the mitochondria. However, the mechanism responsible for this adaptation are poorly understood. METHODS AND FINDINGS: The current study was undertaken to examine muscle mitochondrial bioenergetics in response to caloric restriction alone or in combination with exercise in 36 young (36.8 ± 1.0 y), overweight (body mass index, 27.8 ± 0.7 kg/m(2)) individuals randomized into one of three groups for a 6-mo intervention: Control, 100% of energy requirements; CR, 25% caloric restriction; and CREX, caloric restriction with exercise (CREX), 12.5% CR + 12.5% increased energy expenditure (EE). In the controls, 24-h EE was unchanged, but in CR and CREX it was significantly reduced from baseline even after adjustment for the loss of metabolic mass (CR, −135 ± 42 kcal/d, p = 0.002 and CREX, −117 ± 52 kcal/d, p = 0.008). Participants in the CR and CREX groups had increased expression of genes encoding proteins involved in mitochondrial function such as PPARGC1A, TFAM, eNOS, SIRT1, and PARL (all, p < 0.05). In parallel, mitochondrial DNA content increased by 35% ± 5% in the CR group (p = 0.005) and 21% ± 4% in the CREX group (p < 0.004), with no change in the control group (2% ± 2%). However, the activity of key mitochondrial enzymes of the TCA (tricarboxylic acid) cycle (citrate synthase), beta-oxidation (beta-hydroxyacyl-CoA dehydrogenase), and electron transport chain (cytochrome C oxidase II) was unchanged. DNA damage was reduced from baseline in the CR (−0.56 ± 0.11 arbitrary units, p = 0.003) and CREX (−0.45 ± 0.12 arbitrary units, p = 0.011), but not in the controls. In primary cultures of human myotubes, a nitric oxide donor (mimicking eNOS signaling) induced mitochondrial biogenesis but failed to induce SIRT1 protein expression, suggesting that additional factors may regulate SIRT1 content during CR. CONCLUSIONS: The observed increase in muscle mitochondrial DNA in association with a decrease in whole body oxygen consumption and DNA damage suggests that caloric restriction improves mitochondrial function in young non-obese adults

    Molecular pathways leading to loss of skeletal muscle mass in cancer cachexia can findings from animal models be translated to humans?

    Get PDF
    Background: Cachexia is a multi-factorial, systemic syndrome that especially affects patients with cancer of the gastrointestinal tract, and leads to reduced treatment response, survival and quality of life. The most important clinical feature of cachexia is the excessive wasting of skeletal muscle mass. Currently, an effective treatment is still lacking and the search for therapeutic targets continues. Even though a substantial number of animal studies have contributed to a better understanding of the underlying mechanisms of the loss of skeletal muscle mass, subsequent clinical trials of potential new drugs have not yet yielded any effective treatment for cancer cachexia. Therefore, we questioned to which degree findings from animal studies can be translated to humans in clinical practice and research. Discussion: A substantial amount of animal studies on the molecular mechanisms of muscle wasting in cancer cachexia has been conducted in recent years. This extensive review of the literature showed that most of their observations could not be consistently reproduced in studies on human skeletal muscle samples. However, studies on human material are scarce and limited in patient numbers and homogeneity. Therefore, their results have to be interpreted critically. Summary: More research is needed on human tissue samples to clarify the signaling pathways that lead to skeletal muscle loss, and to confirm pre-selected drug targets from animal models in clinical trials. In addition, improved diagnostic tools and standardized clinical criteria for cancer cachexia are needed to conduct standardized, randomized controlled trials of potential drug candidates in the future

    A Holistic Landscape Description Reveals That Landscape Configuration Changes More over Time than Composition: Implications for Landscape Ecology Studies

    Get PDF
    International audienceBackground: Space-for-time substitution—that is, the assumption that spatial variations of a system can explain and predict the effect of temporal variations—is widely used in ecology. However, it is questionable whether it can validly be used to explain changes in biodiversity over time in response to land-cover changes.Hypothesis: ere, we hypothesize that different temporal vs spatial trajectories of landscape composition and configuration may limit space-for-time substitution in landscape ecology. Land-cover conversion changes not just the surface areas given over to particular types of land cover, but also affects isolation, patch size and heterogeneity. This means that a small change in land cover over time may have only minor repercussions on landscape composition but potentially major consequences for landscape configuration.Methods: sing land-cover maps of the Paris region for 1982 and 2003, we made a holistic description of the landscape disentangling landscape composition from configuration. After controlling for spatial variations, we analyzed and compared the amplitudes of changes in landscape composition and configuration over time.Results: For comparable spatial variations, landscape configuration varied more than twice as much as composition over time. Temporal changes in composition and configuration were not always spatially matched.Significance: The fact that landscape composition and configuration do not vary equally in space and time calls into question the use of space-for-time substitution in landscape ecology studies. The instability of landscapes over time appears to be attributable to configurational changes in the main. This may go some way to explaining why the landscape variables that account for changes over time in biodiversity are not the same ones that account for the spatial distribution of biodiversity

    Towards successful coordination of electronic health record based-referrals: a qualitative analysis

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Successful subspecialty referrals require considerable coordination and interactive communication among the primary care provider (PCP), the subspecialist, and the patient, which may be challenging in the outpatient setting. Even when referrals are facilitated by electronic health records (EHRs) (<it>i.e</it>., e-referrals), lapses in patient follow-up might occur. Although compelling reasons exist why referral coordination <it>should </it>be improved, little is known about which elements of the complex referral coordination process should be targeted for improvement. Using Okhuysen & Bechky's coordination framework, this paper aims to understand the barriers, facilitators, and suggestions for improving communication and coordination of EHR-based referrals in an integrated healthcare system.</p> <p>Methods</p> <p>We conducted a qualitative study to understand coordination breakdowns related to e-referrals in an integrated healthcare system and examined work-system factors that affect the timely receipt of subspecialty care. We conducted interviews with seven subject matter experts and six focus groups with a total of 30 PCPs and subspecialists at two tertiary care Department of Veterans Affairs (VA) medical centers. Using techniques from grounded theory and content analysis, we identified organizational themes that affected the referral process.</p> <p>Results</p> <p>Four themes emerged: lack of an institutional referral policy, lack of standardization in certain referral procedures, ambiguity in roles and responsibilities, and inadequate resources to adapt and respond to referral requests effectively. Marked differences in PCPs' and subspecialists' communication styles and individual mental models of the referral processes likely precluded the development of a <it>shared </it>mental model to facilitate coordination and successful referral completion. Notably, very few barriers related to the EHR were reported.</p> <p>Conclusions</p> <p>Despite facilitating information transfer between PCPs and subspecialists, e-referrals remain prone to coordination breakdowns. Clear referral policies, well-defined roles and responsibilities for key personnel, standardized procedures and communication protocols, and adequate human resources must be in place before implementing an EHR to facilitate referrals.</p
    corecore