P652The cardioprotective effect of exogenous sphingosine-1-phosphate requires the activation of endogenous sphingosine-1-phosphate via the sphingosine kinase 1

Purpose: Exogenous administration of sphingosine-1-phosphate (S1P) alone, or as part of high density lipoprotein, protects against myocardial infarction. S1P-induced cardioprotection targets the inhibition of the mitochondrial permeability transition pore via mechanisms that remain unclear. In the cell, the endogenous production of S1P from sphingosine is dependent on the activation of sphingosine kinases (SphK) 1 and 2. These two kinases play a role in cardioprotection against ischemia-reperfusion (IR) injury. Therefore, we hypothesised that the cardioprotective effect of exogenous S1P requires the activation of endogenous S1P via SphK. Methods: Isolated cardiomyocytes from adult wildtype mice were exposed to 2 hours of simulated ischemia (SI) in the presence of S1P (10nM) with/without N,N-dimethylsphingosine (DMS, a SphK1 and 2 inhibitor, 10μM) or SKI (a specific SphK1 inhibitor, 15μM). Cell viability was assessed using trypan blue staining and normalised to the normoxic control. Isolated perfused hearts from adult wildtype mice were exposed to 35 minutes of global ischemia followed by 45 minutes of reperfusion (IR) in the presence of S1P (10nM) with/without SKI (10μM). Infarct size (IS) was assessed using tripheyltetrazolium chloride staining and SphK1 activity using a specific biochemical fluorescence based assay kit. Both parameters were normalised to the IR control. Results: In isolated cardiomyocytes, viability under normoxic conditions was 76±1%. SI reduced viability to 52±1% (p< 0.001 vs. normoxia). Pre-treatment with S1P restored the viability to 75±1% (p<0.001 vs. SI). The beneficial effect of S1P was partially inhibited in the presence of DMS (67±4%) (ns vs. S1P) and totally abrogated with SKI pre-treatment (54±2%). Similarly, pre-treatment with S1P in isolated hearts reduced IS following IR from 50±1% (IR control) to 31±2% (S1P) (p<0.001 vs. control). Pre-treatment with SKI abrogated the cardioprotective effect of S1P (56±8%) (p<0.05 vs. S1P) as well as the S1P-induced increase in SphK1 activity (from S1P: 196±79 arbitrary units (AU) to SKI+S1P: 53±27 AU, p<0.05 vs. S1P). Conclusions: Our data, performed in both isolated cardiomyocytes and isolated hearts subjected to an ischemia/reperfusion insult, strongly suggest that exogenous sphingosine-1-phosphate-induced cardioprotection is dependent on the activation of endogenous sphingosine-1-phosphate via sphingosine kinase

River hydraulic modeling with ICESat-2 land and water surface elevation

Advances in geodetic altimetry instruments are providing more accurate measurements, thus enabling satellite missions to produce useful data for narrow rivers and streams. Altimetry missions produce spatially dense land and water surface elevation (WSE) measurements in remote areas where in situ data are scarce that can be combined with hydraulic and/or hydrodynamic models to simulate WSE and estimate discharge. In this study, we combine ICESat-2 (Ice, Cloud and land Elevation Satellite) land and water surface elevation measurements with a low-parameterized hydraulic calibration to simulate WSE and discharge without the need for surveyed cross-sectional geometry and a rainfall–runoff model. ICESat-2 provides an opportunity to map river cross-sectional geometry very accurately, with an along-track resolution of 0.7 m, using the ATL03 product. These measurements are combined with the inland water product ATL13 to calibrate a steady-state hydraulic model to retrieve unobserved hydraulic parameters such as river depth or the roughness coefficient. The low-parameterized model, together with the assumption of steady-state hydraulics, enables the application of a global search algorithm for a spatially uniform parameter calibration at a manageable computational cost. The model performance is similar to that reported for highly parameterized models, with a root mean square error (RMSE) of around 0.41 m. With the calibrated model, we can calculate the WSE time series at any chainage point at any time for an available satellite pass within the river reach and estimate discharge from WSE. The discharge estimates are validated with in situ measurements at two available gauging stations. In addition, we use the calibrated parameters in a full hydrodynamic model simulation, resulting in a RMSE of 0.59 m for the entire observation period.</p

Isolation of microplastics in biota-rich seawater samples and marine organisms.

notes: PMCID: PMC3970126types: Journal Article; Research Support, Non-U.S. Gov'tThis is an open access article that is freely available in ORE or from the publisher's web site. Please cite the published version.Microplastic litter is a pervasive pollutant present in aquatic systems across the globe. A range of marine organisms have the capacity to ingest microplastics, resulting in adverse health effects. Developing methods to accurately quantify microplastics in productive marine waters, and those internalized by marine organisms, is of growing importance. Here we investigate the efficacy of using acid, alkaline and enzymatic digestion techniques in mineralizing biological material from marine surface trawls to reveal any microplastics present. Our optimized enzymatic protocol can digest >97% (by weight) of the material present in plankton-rich seawater samples without destroying any microplastic debris present. In applying the method to replicate marine samples from the western English Channel, we identified 0.27 microplastics m(-3). The protocol was further used to extract microplastics ingested by marine zooplankton under laboratory conditions. Our findings illustrate that enzymatic digestion can aid the detection of microplastic debris within seawater samples and marine biota.Natural Environment Research Council (NERC

Plastic microfibre ingestion by deep-sea organisms

Plastic waste is a distinctive indicator of the world-wide impact of anthropogenic activities. Both macro- and micro-plastics are found in the ocean, but as yet little is known about their ultimate fate and their impact on marine ecosystems. In this study we present the first evidence that microplastics are already becoming integrated into deep-water organisms. By examining organisms that live on the deep-sea floor we show that plastic microfibres are ingested and internalised by members of at least three major phyla with different feeding mechanisms. These results demonstrate that, despite its remote location, the deep sea and its fragile habitats are already being exposed to human waste to the extent that diverse organisms are ingesting microplastics

Distinct Mechanisms Underlying Tolerance to Intermittent and Constant Hypoxia in Drosophila melanogaster

BACKGROUND: Constant hypoxia (CH) and intermittent hypoxia (IH) occur during several pathological conditions such as asthma and obstructive sleep apnea. Our research is focused on understanding the molecular mechanisms that lead to injury or adaptation to hypoxic stress using Drosophila as a model system. Our current genome-wide study is designed to investigate gene expression changes and identify protective mechanism(s) in D. melanogaster after exposure to severe (1% O(2)) intermittent or constant hypoxia. METHODOLOGY/PRINCIPAL FINDINGS: Our microarray analysis has identified multiple gene families that are up- or down-regulated in response to acute CH or IH. We observed distinct responses to IH and CH in gene expression that varied in the number of genes and type of gene families. We then studied the role of candidate genes (up-or down-regulated) in hypoxia tolerance (adult survival) for longer periods (CH-7 days, IH-10 days) under severe CH or IH. Heat shock proteins up-regulation (specifically Hsp23 and Hsp70) led to a significant increase in adult survival (as compared to controls) of P-element lines during CH. In contrast, during IH treatment the up-regulation of Mdr49 and l(2)08717 genes (P-element lines) provided survival advantage over controls. This suggests that the increased transcript levels following treatment with either paradigm play an important role in tolerance to severe hypoxia. Furthermore, by over-expressing Hsp70 in specific tissues, we found that up-regulation of Hsp70 in heart and brain play critical role in tolerance to CH in flies. CONCLUSIONS/SIGNIFICANCE: We observed that the gene expression response to IH or CH is specific and paradigm-dependent. We have identified several genes Hsp23, Hsp70, CG1600, l(2)08717 and Mdr49 that play an important role in hypoxia tolerance whether it is in CH or IH. These data provide further clues about the mechanisms by which IH or CH lead to cell injury and morbidity or adaptation and survival

Genotyping the hepatitis B virus with a fragment of the HBV DNA polymerase gene in Shenyang, China

The hepatitis B virus (HBV) has been classified into eight genotypes (A-H) based on intergenotypic divergence of at least 8% in the complete nucleotide sequence or more than 4% in the S gene. To facilitate the investigation of the relationship between the efficacy of drug treatment and the mutation with specific genotype of HBV, we have established a new genotyping strategy based on a fragment of the HBV DNA polymerase gene. Pairwise sequence and phylogenetic analyses were performed using CLUSTAL V (DNASTAR) on the eight (A-H) standard full-length nucleotide sequences of HBV DNA from GenBank (NCBI) and the corresponding semi-nested PCR products from the HBV DNA polymerase gene. The differences in the semi-nested PCR fragments of the polymerase genes among genotypes A through F were greater than 4%, which is consistent with the intergenotypic divergence of at least 4% in HBV DNA S gene sequences. Genotyping using the semi-nested PCR products of the DNA polymerase genes revealed that only genotypes B, C, and D were present in the 50 cases, from Shenyang, China, with a distribution of 11 cases (22%), 25 cases (50%), and 14 cases (28%) respectively. These results demonstrate that our new genotyping method utilizing a fragment of the HBV DNA polymerase gene is valid and can be employed as a general genotyping strategy in areas with prevalent HBV genotypes A through F. In Shenyang, China, genotypes C, B, and D were identified with this new genotyping method, and genotype C was demonstrated to be the dominant genotype

Inequalities in public water supply fluoridation in Brazil: An ecological study

Background. The literature is scarce on the social and geographic inequalities in the access to and implementation of the fluoridation of public water supplies. This study adds knowledge to the Brazilian experience of the chronic privation of water and wastewater policies, access to potable water and fluoridation in the country. Thus, the aim of this study was to verify possible inequalities in the population's access to fluoridated drinking water in 246 Brazilian municipalities. Methods. The information on the process of water fluoridation in the municipalities and in the macro region in which each municipality is located was obtained from the national epidemiological survey which was concluded in 2003. The data relating to the human development index at municipal level (HDI-M) and access to mains water came from the Brazilian Human Development Atlas, whilst the size of the population was obtained from a governmental source. The Fisher exact test (P < 0.05) was employed to identify significant associations between the explanatory variables and their ability to predict the principal outcomes of interest to this study, namely the presence or absence of the water fluoridation process in the municipalities as well as the length of time during which this measure has been implemented. Linear regression was used to observe the associations between the relevant variables in a multivariate environment. Results. The results clearly showed that there is a relationship between municipalities with larger populations, located in more socio-economically advantaged regions and with better HDI-M, and where fluoridation is both present and has been implemented for a longer period of time (started before 1990). Conclusion. The findings suggest that the aim of treating water with fluoride may not be being adequately achieved, requiring more effective strategies so that access to this measure can be expanded equitably.81Hart, J.T., The inverse care law (1971) Lancet, 1 (7696), pp. 405-12. , 4100731Victora, C.G., Vaughan, J.P., Barros, F.C., Silva, A.C., Tomasi, E., Explaining trends in inequities: Evidence from Brazilian child health studies (2000) Lancet, 356 (9235), pp. 1093-98. , 10.1016/S0140-6736(00)02741-0 11009159Basting, R.T., Pereira, A.C., Meneghim, M.C., Evaluation of dental caries prevalence in students from Piracicaba, SP, Brazil, after 25 years of fluoridation of the public water supply (1997) Rev Odontol Univ São Paulo, 11 (4), pp. 287-92. , 10.1590/S0103-06631997000400010Lawrence, H.P., Sheiham, A., Caries progression in 12 to 16-year-old schoolchildren in fluoridated and fluoride-deficient areas in Brazil (1997) Community Dent Oral Epidemiol, 25 (6), pp. 402-11. , 10.1111/j.1600-0528.1997.tb01730.x 9429812Pereira, A.C., Mialhe, F.L., Bianchini, F.L.C., Prevalence of caries and dental floozies in scholars from cities with different fluoride concentrations in drinking water (2001) Rev Bras Odontol Sade Coletiva, 2 (1), pp. 34-9For Disease Control, C., Prevention, Achievementsin Public Health, 1900-1999: Fluoridation of drinking water to prevent dental caries (1999) Morbidity and Mortality Weekly Report, 48 (41), pp. 933-40For Disease Control, C., Prevention, Ten great public health achievements -United Sates, 1900-1999 (1999) Morbidity and Mortality Weekly Report, 48 (12), pp. 241-3. , 10220250American Health Organization, P., XV Directing Council of the Pan American Health Organization - Resolutions, 1964, , http://www.paho.org/English/GOV/CD/ftcd_15.htm(2003) The World Oral Health Report 2003, , http://www.who.int/oral_health, Geneva: WHOMcDonagh, M.S., Whiting, P.F., Wilson, P.M., Sutton, A.J., Chestnutt, I., Cooper, J., Misso, K., Kleijnen, J., Systematic review of water fluoridation (2000) BMJ, 321 (7265), pp. 855-9. , 11021861 10.1136/bmj.321.7265.855Bratthall, D., Hänsel-Petersson, G., Sundberg, H., Reasons for the caries decline: What do the experts believe? (1996) Eur J Oral Sci, 104 (4 PART 2), pp. 416-22. , 10.1111/j.1600-0722.1996.tb00104.x 8930592Narvai, P.C., Dental caries and fluorine: A twentieth century relation (2000) Cinc Sade Coletiva, 5 (2), pp. 381-92. , 10.1590/S1413-81232000000200011Peres, M.A., Fernandes, L.S., Peres, K.G., Inequality of water fluoridation in Southern Brazil - The inverse equity hypothesis revisited (2004) Soc Sci Med, 58 (6), pp. 1181-9. , 10.1016/S0277-9536(03)00289-2 14723912Peres, M.A., Antunes, J.L.F., Peres, K.G., Is water fluoridation effective in reducing inequalities in dental caries distribution in developing countries? (2006) Sozial und Präventiv Medizin, 51 (5), pp. 1-9Peres, K.G., Bastos, J.R., Mrdo, L., Relationship between severity of dental caries and social and behavioral factors in children (2000) Rev Saude Publica, 34 (4), pp. 402-8. , 10973161Maltz, M., Barbachan Silva, E.B., Relationship between caries, gingivitis and fluorosis and the socioeconomic status among school children (2001) Rev Saude Publica, 35 (2), pp. 170-6. , 11359204Moysés, S.J., Desigualdades em Sade Bucal e Desenvolvimento Humano: Um ensaio em preto, branco e alguns tons de cinza (2001) Rev Bras Odontol Sade Coletiva, 1 (1), pp. 7-17Patussi, M.P., Marcenes, W., Croucher, R., Sheiham, A., Social deprivation, income inequality, social cohesion and dental caries in Brazilian school children (2001) Soc Sci Med, 53 (7), pp. 915-25. , 10.1016/S0277-9536(00)00391-9 11522137Antunes, J.L.F., Frazão, P., Narvai, P.C., Bispo, C.M., Pegoretti, T., Spatial analysis to identify differentials in dental needs by area-based measures (2002) Community Dent Oral Epidemiol, 30 (2), pp. 133-42. , 10.1034/j.1600-0528.2002.300207.x 12000354Peres, M.A., Peres, K.G., Antunes, J.L.F., Junqueira, S.R., Frazão, P., Narvai, P.C., The association between socioeconomic development at the town level and the distribution of dental caries in Brazilian children (2003) Rev Panam Salud Publica, 14 (3), pp. 149-57. , 10.1590/S1020-49892003000800001 14653902Antunes, J.L.F., Narvai, P.C., Nugent, Z.J., Measuring inequalities in the distribution of dental caries (2004) Community Dent Oral Epidemiol, 32 (1), pp. 41-8. , 10.1111/j.1600-0528.2004.00125.x 14961839Antunes, J.L.F., Peres, M.A., De Campos Mello, T.R., Waldman, E.A., Multilevel assessment of determinants of dental caries experience in Brazil (2006) Community Dent Oral Epidemiol, 34 (2), pp. 146-152. , 10.1111/j.1600-0528.2006.00274.x 16515679Narvai, P.C., Frazão, P., Roncalli, A.G., Antunes, J.L.F., Dental caries in Brazil: Decline, polarization, inequality and social exclusion (2006) Rev Panam Salud Publica, 19 (6), pp. 385-93. , 10.1590/S1020-49892006000600004 16968593Projeto, S.B., Brasil, Condiçes de sade bucal da população brasileira 2002-2003. Resultados principais (2004) Brasília-DF: Ministério da Sade, Secretaria de Atenção Sade, Departamento de Atenção Básica, Coordenação Nacional de Sade BucalCarmichael, C.L., Rugg-Gunn, A.J., French, A.D., Cranage, J.D., The effect of fluoridation upon the relationship between caries experience and social class in 5-year-old children in Newcastle and Northumberland in 1987 (1980) Br Dent J, 149 (6), pp. 163-7. , 10.1038/sj.bdj.4804479 6931610Bradnock, G., Marchment, M.D., Anderson, R.J., Social background, fluoridation and caries experience in 5-year-old population in the West Midlands (1984) Br Denl J, 156 (4), pp. 127-31. , 10.1038/sj.bdj.4805287 6584119Jones, C.M., Taylor, G.O., Whittle, J.G., Evans, D., Trotter, D.P., Water fluoridation, tooth decay in 5 years olds, and social deprivation measured by the Jarman score: Analysis of data from British dental surveys (1997) BMJ, 315 (7107), pp. 514-17. , 9329305Riley, J.C., Lennon, M.A., Ellwood, R.P., The effect of water fluoridation and social inequalities on dental caries in 5-year-old children (1999) Int Dent J, 28 (2), pp. 300-5. , 10342695Congresso Nacional, Brasil., Lei Federal no. de 19/09/1990 (1990) Diário Oficial da União 20 Set, p. 18055Morgenstern, H., Ecological studies (1998) Modern Epidemiology, pp. 459-80. , Baltimore: Lippincot Williamns & Wilkins Rothman K, Greenland S(2000) Informaçes de Sade: População Residente, , http://w3.datasus.gov.br/datasus/datasus.php?area= 359A1B379C6D0E0F359G23HIJd6L26M0N&VInclude=./site/infsaude.php, Departamento de Informática do Sistema nico de Sade (DATASUS)(2003) Atlas Do Desenvolvimento Humano No Brasil, Versão 1.0.0, , Programa das Naçes Unidas para o Desenvolvimento Brasília: PNUDLallo, R., Myburgh, N.G., Hobdell, M.H., Dental caries, socio-economic development and national oral health profiles (1999) Int Dent J, 49, pp. 196-202. , 10858754Baldani, M.H., Narvai, P.C., Antunes, J.L.F., Cárie dentária e condiçes scio-econômicas no Estado do Paraná, Brasil, 1996 (2002) Cad Sade Pblica, 18 (3), pp. 755-63. , 10.1590/S0102-311X2002000300024Qizilbash, M., On the Measurement of Human Development (2002) UNDP, , http://hdr.undp.org/docs/training/oxford/presentations/ Qizilbash_HDIcritique.pdfBurt, B.A., Fluoridation and social equity (2002) J Public Health Dent, 62 (4), pp. 195-200. , 10.1111/j.1752-7325.2002.tb03445.x 12474623For Disease Control, C., Prevention, Recommendation focusing fluoride to prevent and control dental caries in the United States (2001) Morbidity and Mortality Weekly Report, 50 (14), pp. 1-42Griffin, S.O., Jones, K., Tomar, S.L., An economic evaluation of community water fluoridation (2001) J Public Health Dent, 61 (2), pp. 78-86. , 10.1111/j.1752-7325.2001.tb03370.x 11474918Bleicher, L., Frota, F.H.S., Fluoretação da água: Uma questão de política pblica - O caso do Estado do Ceará (2006) Cin Sade Coletiva, 11 (1), pp. 71-8Frias, A.C., Narvai, P.C., Arajo, M.E., Zilbovicius, C., Antunes, J.L.F., Custo da fluoretação das águas de abastecimento pblico, estudo de caso -Município de São Paulo, Brasil, período de 1985-2003 (2006) Cad Sade Pblica, 22 (6), pp. 1237-46. , 10.1590/S0102-311X2006000600013Congresso Nacional, Brasil., (1974) Lei Federal No. 6.050, 3, p. 107. , Brasília: Departamento de Imprensa Nacional Atos do Poder Legislativo. Leis de Abril a JunhoDuarte, C.M.R., Eqüidade na legislação: Um princípio do sistema de sade brasileiro? (2000) Cin Sade Coletiva, 5 (2), pp. 443-63Whitehead, M., The concepts and principles of equity and health (1992) Int J Health Serv, 22 (3), pp. 429-45. , 10.2190/986L-LHQ6-2VTE-YRRN 164450

New Dual Mode Gadolinium Nanoparticle Contrast Agent for Magnetic Resonance Imaging

BACKGROUND: Liposomal-based gadolinium (Gd) nanoparticles have elicited significant interest for use as blood pool and molecular magnetic resonance imaging (MRI) contrast agents. Previous generations of liposomal MR agents contained gadolinium-chelates either within the interior of liposomes (core-encapsulated gadolinium liposomes) or presented on the surface of liposomes (surface-conjugated gadolinium liposomes). We hypothesized that a liposomal agent that contained both core-encapsulated gadolinium and surface-conjugated gadolinium, defined herein as dual-mode gadolinium (Dual-Gd) liposomes, would result in a significant improvement in nanoparticle-based T1 relaxivity over the previous generations of liposomal agents. In this study, we have developed and tested, both in vitro and in vivo, such a dual-mode liposomal-based gadolinium contrast agent. METHODOLOGY/PRINCIPAL FINDINGS: THREE TYPES OF LIPOSOMAL AGENTS WERE FABRICATED: core-encapsulated, surface-conjugated and dual-mode gadolinium liposomes. In vitro physico-chemical characterizations of the agents were performed to determine particle size and elemental composition. Gadolinium-based and nanoparticle-based T1 relaxivities of various agents were determined in bovine plasma. Subsequently, the agents were tested in vivo for contrast-enhanced magnetic resonance angiography (CE-MRA) studies. Characterization of the agents demonstrated the highest gadolinium atoms per nanoparticle for Dual-Gd liposomes. In vitro, surface-conjugated gadolinium liposomes demonstrated the highest T1 relaxivity on a gadolinium-basis. However, Dual-Gd liposomes demonstrated the highest T1 relaxivity on a nanoparticle-basis. In vivo, Dual-Gd liposomes resulted in the highest signal-to-noise ratio (SNR) and contrast-to-noise ratio in CE-MRA studies. CONCLUSIONS/SIGNIFICANCE: The dual-mode gadolinium liposomal contrast agent demonstrated higher particle-based T1 relaxivity, both in vitro and in vivo, compared to either the core-encapsulated or the surface-conjugated liposomal agent. The dual-mode gadolinium liposomes could enable reduced particle dose for use in CE-MRA and increased contrast sensitivity for use in molecular imaging