RESUMEN
BACKGROUND: Type 2 diabetes stems from obesity-associated insulin resistance, and in the genetically susceptible, concomitant pancreatic ß-cell failure can occur, which further exacerbates hyperglycemia. Recent work by our group and others has shown that the natural polyphenol curcumin attenuates the development of insulin resistance and hyperglycemia in mouse models of hyperinsulinemic or compensated type 2 diabetes. Although several potential downstream molecular targets of curcumin exist, it is now recognized to be a direct inhibitor of proteasome activity. We now show that curcumin also prevents ß-cell failure in a mouse model of uncompensated obesity-related insulin resistance (Lepr(db/db) on the Kaliss background). RESULTS: In this instance, dietary supplementation with curcumin prevented hyperglycemia, increased insulin production and lean body mass, and prolonged lifespan. In addition, we show that short-term in vivo treatment with low dosages of two molecularly distinct proteasome inhibitors celastrol and epoxomicin reverse hyperglycemia in mice with ß-cell failure by increasing insulin production and insulin sensitivity. CONCLUSIONS: These studies suggest that proteasome inhibitors may prove useful for patients with diabetes by improving both ß-cell function and relieving insulin resistance.
Asunto(s)
Curcumina/farmacología , Diabetes Mellitus Experimental/tratamiento farmacológico , Resistencia a la Insulina , Células Secretoras de Insulina/efectos de los fármacos , Inhibidores de Proteasoma/farmacología , Células 3T3-L1 , Animales , Composición Corporal , Supervivencia Celular/efectos de los fármacos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Suplementos Dietéticos , Hemoglobina Glucada/metabolismo , Homeostasis , Hiperglucemia/prevención & control , Insulina/sangre , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/citología , Células Secretoras de Insulina/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Obesidad/sangre , Obesidad/tratamiento farmacológico , Oligopéptidos/farmacología , Triterpenos Pentacíclicos , Polifenoles/farmacología , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Triterpenos/farmacologíaRESUMEN
AIMS: To determine the extent to which discrepancies between qPCR and culture-based results in beach water quality monitoring can be attributed to: (i) within-method variability, (ii) between-method difference within each method class (qPCR or culture) and (iii) between-class difference. METHODS AND RESULTS: We analysed 306 samples using two culture-based (EPA1600 and Enterolert) and two qPCR (Taqman and Scorpion) methods, each in duplicate. Both qPCR methods correlated with EPA1600, but regression analyses indicated approximately 0·8 log10 unit overestimation by qPCR compared to culture methods. Differences between methods within a class were less than half of this and were minimal for between-replicate within a method. Using the 104 Enterococcus per 100 ml management decision threshold, Taqman qPCR indicated the same decisions as EPA1600 for 87% of the samples, but indicated beach posting for unhealthful water when EPA1600 did not for 12% of the samples. After accounting for within-method and within-class variability, 8% of the samples exhibited true between-class discrepancy where both qPCR methods indicated beach posting while both culture methods did not. CONCLUSION: Measurement target difference (DNA vs growth) accounted for the majority of the qPCR-vs-culture discrepancy, but its influence on monitoring application is outweighed by frequent incorrect posting with culture methods due to incubation time delay. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to quantify the frequency with which culture-vs-qPCR discrepancies can be attributed to target difference - vs - method variability.
Asunto(s)
Enterococcus/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Microbiología del Agua , Playas , Técnicas de Cultivo de Célula , Enterococcus/genética , Agua de Mar/microbiología , Calidad del AguaRESUMEN
AIMS: Draft criteria for the optional use of qPCR for recreational water quality monitoring have been published in the United States. One concern is that inhibition of the qPCR assay can lead to false-negative results and potentially inadequate public health protection. We evaluate the effectiveness of strategies for minimizing the impact of inhibition. METHODS AND RESULTS: Five qPCR method permutations for measuring Enterococcus were challenged with 133 potentially inhibitory fresh and marine water samples. Serial dilutions were conducted to assess Enterococcus target assay inhibition, to which inhibition identified using four internal controls (IC) was compared. The frequency and magnitude of inhibition varied considerably among qPCR methods, with the permutation using an environmental master mix performing substantially better. Fivefold dilution was also effective at reducing inhibition in most samples (>78%). ICs were variable and somewhat ineffective, with 54-85% agreement between ICs and serial dilution. CONCLUSIONS: The current IC methods appear to not accurately predict Enterococcus inhibition and should be used with caution; fivefold dilution and the use of reagents designed for environmental sample analysis (i.e. more robust qPCR chemistry) may be preferable. SIGNIFICANCE AND IMPACT OF THE STUDY: Suitable approaches for defining, detecting and reducing inhibition will improve implementation of qPCR for water monitoring.
Asunto(s)
Enterococcus/aislamiento & purificación , Monitoreo del Ambiente/normas , Reacción en Cadena de la Polimerasa/normas , Microbiología del Agua , Monitoreo del Ambiente/métodos , Agua Dulce/microbiología , Recreación , Reproducibilidad de los Resultados , Agua de Mar/microbiología , Estados UnidosRESUMEN
AIMS: A recent study that evaluated 22 methods for enumerating faecal indicator bacteria in sand recommended standardization to a preferred method, but all researchers involved in that study had extensive experience in processing sand samples. The purpose of this study was to evaluate how well the recommended method can be transferred to laboratories without such experience. METHODS AND RESULTS: Eight southern California laboratories that rarely measure bacteria in sand processed six sand and three water samples in replicates to assess repeatability. Among-laboratory variability was found to be less than within-laboratory variability, with no significant differences in results among any of the laboratories. Moreover, within-laboratory variability was comparable between the sand and water samples, indicating that the elution procedure added little additional method error even when performed by laboratories without prior experience. CONCLUSIONS: The simple extraction method for enumerating Enterococcus in beach sands was easily transferable to and repeatable among laboratories with little or no prior experience. SIGNIFICANCE AND IMPACT OF THE STUDY: The demonstrated success of technology transfer will further demonstrate the success of method standardization and adoption, aiding in understanding of how sands affect surface water quality.
Asunto(s)
Enterococcus/aislamiento & purificación , Monitoreo del Ambiente/métodos , California , Heces/microbiología , Humanos , Agua de Mar/microbiología , Dióxido de Silicio , Calidad del AguaRESUMEN
AIMS: The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique. METHODS AND RESULTS: Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. CONCLUSIONS: The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types. SIGNIFICANCE AND IMPACT OF THE STUDY: Method standardization will improve the understanding of how sands affect surface water quality.
Asunto(s)
Playas , Enterococcus/aislamiento & purificación , Escherichia coli/aislamiento & purificación , Sedimentos Geológicos/microbiología , Tamaño de la Partícula , Dióxido de SilicioRESUMEN
During the last decade, there have been substantial scientific advances in the development of indices that measure the condition of biological ecosystem elements in coastal and estuarine waters. Though successful, these advances were only the initial steps and a special session on use of indices in ecological integrity assessments was held at the Coastal and Estuarine Research Federation meeting to focus the field on the most appropriate directions for the next decade. The session identified four primary scientific challenges: (i) reduce the array of indices by identifying the index approaches that are most widely successful; (ii) establish minimum criteria for index validation; (iii) intercalibrate methods to achieve uniform assessment scales across geographies and habitats; and (iv) integrate indices across ecosystem elements. Where an explosion of indices characterized the last decade, the next decade needs to be characterized by consolidation. With increased knowledge and understanding about the strengths and weaknesses of competing index approaches, the field needs to unify approaches that provide managers with the simple answers they need to use ecological condition information effectively and efficiently.
Asunto(s)
Indización y Redacción de Resúmenes , Conservación de los Recursos Naturales , Ecosistema , Animales , Calibración , Conservación de los Recursos Naturales/tendencias , Biología Marina , Reproducibilidad de los Resultados , Agua de MarRESUMEN
BACKGROUND: Obesity is currently viewed as a state of chronic low-grade inflammation in which there is a pro-inflammatory alteration in the serum adipocytokine profile as well as an infiltration of white adipose tissue by activated macrophages. The etiology of this inflammation, however, is poorly understood. METHODS: Hypothesizing that local hypoxia within expanding white adipose tissue depots may contribute to obesity-related inflammation, we compared body composition, serum inflammatory marker concentrations and the expression of several hypoxia-regulated genes in white adipose tissue derived from lean, dietary-induced obese (DIO) and ob/ob male C57BL/6J mice. We also examined white adipose tissue for the presence of hypoxia using both a pimonidazole-based antibody system and a fiberoptic sensor for real-time pO(2) quantification in vivo. Finally, using cell-specific leukocyte antibodies, we performed immunohistochemistry and flow cytometric analyses to further characterize the cellular nature of adipose inflammation. RESULTS: We determined that obesity in male C57BL/6J mice is associated with increased expression of HIF (hypoxia-inducible factor) isoforms and GLUT-1, and that white adipose tissue hypoxia was present in the obese mice. Immunohistochemistry revealed hypoxic areas to colocalize predominantly with F4/80+ macrophages. Interestingly, CD3+ T cells were present in large numbers within the adipose of both DIO and ob/ob obese mice, and flow cytometry revealed their adipose to possess significantly more CD8+ T cells than their lean cohort. CONCLUSIONS: White adipose hypoxia and cytotoxic T-cell invasion are features of obesity in C57BL/6J mice and are potential contributors to their local and generalized inflammatory state.
Asunto(s)
Tejido Adiposo/metabolismo , Hipoxia de la Célula/fisiología , Obesidad/inmunología , Tejido Adiposo/patología , Animales , Complejo CD3/inmunología , Linfocitos T CD8-positivos/inmunología , Transportador de Glucosa de Tipo 1/metabolismo , Factor 1 Inducible por Hipoxia/metabolismo , Inmunohistoquímica , Macrófagos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Obesidad/metabolismo , Obesidad/fisiopatología , Linfocitos T Citotóxicos/fisiologíaRESUMEN
Previous studies of neustonic debris have been limited to surface sampling. Here we conducted two trawl surveys, one before and one shortly after a rain event, in which debris and zooplankton density were measured at three depths in Santa Monica Bay, California. Surface samples were collected with a manta trawl, mid-depth samples with a bongo net and bottom samples with an epibenthic sled, all having 333 micron nets. Density of debris was greatest near the bottom, least in midwater. Debris density increased after the storm, particularly at the sampling site closest to shore, reflecting inputs from land-based runoff and resuspended matter. The mass of plastic collected exceeded that of zooplankton, though when the comparison was limited to plastic debris similar to the size of most zooplankton, zooplankton mass was three times that of debris.
Asunto(s)
Monitoreo del Ambiente/estadística & datos numéricos , Contaminación Ambiental/estadística & datos numéricos , Plásticos , Agua de Mar/análisis , Contaminantes del Agua/análisis , Zooplancton/fisiología , Animales , California , Densidad de Población , LluviaRESUMEN
Membrane filtration (MF) and multiple tube fermentation (MTF) have been used for decades to measure indicator bacteria levels in beach water samples, but new methods based on chromogenic substrate (CS) technology are becoming increasingly popular. Only a few studies have compared results among these methods and they have generally been based on samples collected from a limited number of sites during dry weather. In this study, samples were collected from 108 sites the day after a major rainstorm, and three indicator bacteria (total coliforms (TCs), fecal coliforms (FCs) or E. coli, and enterococci (EC)) were each measured using MF, MTF, and CS. Sampling sites were selected using a stratified random design, stratified by open sandy beach, rocky shoreline, and beach areas near urban runoff outlets. The CS results were found to be highly correlated with both MF and MTF for all three indicators regardless of whether the samples were taken along open shoreline or near a runoff outlet. While correlated, TC values were higher using the CS method, consistent with other studies that have demonstrated false positives with this method. FC values were 12% lower with CS, reflecting the specificity of the CS method for E. coli rather than for the entire FC group. No significant differences were observed for EC, although some differences were observed within specific laboratories. Differences for all of these indicators were small enough that, when assessed categorically, there was more than 90% agreement between CS methods and either MF or MTF methods as to whether State of California Beach Water Quality Standards were met or exceeded.
Asunto(s)
Monitoreo del Ambiente/métodos , Escherichia coli/aislamiento & purificación , Agua de Mar/microbiología , Microbiología del Agua , California , Reacciones Falso Positivas , Fermentación , Filtración , Membranas Artificiales , Lluvia , Valores de Referencia , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Santa Monica Bay is an open coastal embayment located directly seaward of Los Angeles, California. The Bay provides vital economic value through its water-dependent activities, such as swimming, diving, boating, and fishing. An increase from 100,000 residents in 1900 to 10 million in 2000 has imposed numerous environmental stressors on the Bay, including urbanization of the watershed. Pollutant discharges into the Bay increased throughout the early part of the century, but declined following passage of the Clean Water Act in 1972. Since that time, the predominant source of pollutant inputs has changed from point sources to non-point urban runoff. To assess how present-day and historical pollution interact to affect the environmental quality of Santa Monica Bay, three organizations collaborated on a multi-disciplinary study in 1997, towards which this volume is focused. This paper details the temporal patterns of anthropogenic influence on Santa Monica Bay to provide context for the papers that follow.
Asunto(s)
Contaminantes del Agua/análisis , Abastecimiento de Agua , Agricultura , California , Ciudades , Ambiente , Monitoreo del Ambiente , Relaciones Interprofesionales , Eliminación de Residuos Líquidos , Movimientos del Agua , Contaminación del Agua/prevención & controlRESUMEN
In July 1999, California's ocean recreational bacterial water quality standards were changed from a total coliform (TC) test to a standard requiring testing for all three bacterial indicators: TC, fecal coliforms (FC), and enterococci (EC). To compare the relationship between the bacterial indicators, and the effect that changing the standards would have on recreational water regulatory actions, three regional studies were conducted along the southern California shoreline from Santa Barbara to San Diego, California. Two studies were conducted during dry weather and one following a large storm event. In each study, samples were collected at over 200 sites which were selected using a stratified random design, with strata consisting of open beach areas and rocky shoreline, and areas near freshwater outlets that drain land-based runoff. During the dry weather studies, samples were collected once per week for 5 weeks. For the storm event study, sampling occurred on a single day about 24 h following the storm. The three indicator bacteria were measured at each site and the results were compared to the single sample standards (TC > 10,000; FC > 400 and EC > 104 MPN or cfu/100 ml). EC was the indicator that failed the single sample standards most often. During the wet weather study, 99% of all standard failures were detected using EC, compared with only 56% for FC, and 40% for TC. During the Summer Study, EC was again the indicator that failed the single sample standards most often, with 60% of the failures for EC alone. The increased failure of the EC standard occurred consistently regardless of whether the sample was collected at a beach or rocky shoreline site, or at a site near a freshwater outlet. Agreement among indicators was better during wet weather than during dry weather. During dry weather, agreement among indicators was better near freshwater outlets than along open shoreline. Cumulatively, our results suggest that replacement of a TC standard with an EC standard will lead to a five-fold increase in failures during dry weather and a doubling of failures during wet weather. Replacing a TC standard with one based on all three indicators will lead to an eight-fold increase in failures. Changes in the requirements for water quality testing have strong implications for increases in beach closures and restrictions.
Asunto(s)
Enterobacteriaceae/aislamiento & purificación , Enterococcus/aislamiento & purificación , Monitoreo del Ambiente/métodos , Recreación , Microbiología del Agua , Abastecimiento de Agua , California , Heces/microbiología , Control de Calidad , Lluvia , Reproducibilidad de los Resultados , Estaciones del AñoRESUMEN
The density of neustonic plastic particles was compared to that of zooplankton in the coastal ocean near Long Beach, California. Two trawl surveys were conducted, one after an extended dry period when there was little land-based runoff, the second shortly after a storm when runoff was extensive. On each survey, neuston samples were collected at five sites along a transect parallel to shore using a manta trawl lined with 333 micro mesh. Average plastic density during the study was 8 pieces per cubic meter, though density after the storm was seven times that prior to the storm. The mass of plastics was also higher after the storm, though the storm effect on mass was less than it was for density, reflecting a smaller average size of plastic particles after the storm. The average mass of plastic was two and a half times greater than that of plankton, and even greater after the storm. The spatial pattern of the ratio also differed before and after a storm. Before the storm, greatest plastic to plankton ratios were observed at two stations closest to shore, whereas after the storm these had the lowest ratios.
Asunto(s)
Plásticos , Contaminantes del Agua/análisis , Zooplancton , Animales , California , Monitoreo del Ambiente , Tamaño de la Partícula , Dinámica Poblacional , Lluvia , Movimientos del AguaRESUMEN
Most assessments of fish contamination in Southern California use ecologically different species from different sites. Use of ecologically similar species (a guild) might provide better assessments of fish contamination across different sites and depths. In July-August 1997, we collected samples of four sanddab guild species at 22 sites where species pairs co-occurred and determined total DDT concentrations in homogenized whole fish composites. Log-transformed DDT concentrations were highly correlated among all species pairs within this guild. All relationships were linear over the range observed, with slopes not statistically different from unity. The variability in response among species was about four times the variability encountered among replicates within species, but 15 times smaller than the variability among sites. Together, these results suggest that the sanddab guild, widespread on soft bottoms of the Southern California coastal shelf, can be used as a "superspecies" in bathymetrically diverse regional assessments of fish tissue contamination.
Asunto(s)
DDT/farmacocinética , Peces , Insecticidas/farmacocinética , Animales , California , Cadena Alimentaria , Dinámica Poblacional , Distribución TisularRESUMEN
Sindbis virus (SV) is an alphavirus used as a model for studying the pathogenesis of viral encephalitis. In this study we examined the effects and the mechanisms involved in the apoptosis induced by SV in PC-12 cells, and the role of a vFLIP in this process. Infection of PC-12 cells with a neurovirulent strain of SV, SVNI, induced cell apoptosis. Overexpression of vFLIP encoded by the HHV-8 or treatment with a caspase-8 inhibitor inhibited cell apoptosis. SVNI induced an increase in the expression of tumor necrosis factor alpha (TNF-alpha), and pre-treatment of the cells with an anti-TNF-alpha blocking antibody or with soluble TNF-alpha receptor abrogated the apoptotic effect of SVNI. Moreover, TNF-alpha R1 knockout mice were more resistant to the cytopathic effects of the virus as compared to control animals. Our results indicate that the apoptosis induced by SVNI is mediated by activation of caspase-8, and that TNF-alpha plays an important role in the apoptotic response.
Asunto(s)
Apoptosis , Péptidos y Proteínas de Señalización Intracelular , Factor de Necrosis Tumoral alfa/fisiología , Animales , Anticuerpos Monoclonales , Proteína Reguladora de Apoptosis Similar a CASP8 y FADD , Proteínas Portadoras , Caspasa 8 , Caspasa 9 , Caspasas/metabolismo , Expresión Génica , Ratones , Células PC12 , ARN Mensajero/biosíntesis , Ratas , Virus Sindbis/fisiología , Replicación ViralRESUMEN
In this study we characterized the expression of Fas and Fas ligand in different types of meningiomas and examined the effect of Fas ligation on the death of meningioma cells in culture. Using Western blot analysis, we found that extracts derived from anaplastic and atypical meningiomas expressed high levels of Fas, whereas benign meningiomas did not express detectable levels of this protein. All of the meningiomas examined expressed low levels of Fas ligand. Cultures of anaplastic meningiomas also expressed Fas and treatment of these cells with anti-Fas antibody induced cell death. The results of this study indicate that Fas is preferentially expressed in atypical and anaplastic meningiomas and suggest that it is involved in the increased apoptosis observed in these tumors.
Asunto(s)
Apoptosis/fisiología , Glicoproteínas de Membrana/inmunología , Glicoproteínas de Membrana/metabolismo , Neoplasias Meníngeas/fisiopatología , Meningioma/fisiopatología , Anticuerpos/inmunología , Muerte Celular/fisiología , Proteína Ligando Fas , Humanos , Neoplasias Meníngeas/metabolismo , Neoplasias Meníngeas/patología , Meningioma/clasificación , Meningioma/metabolismo , Meningioma/patología , Persona de Mediana Edad , Células Tumorales Cultivadas , Receptor fas/fisiologíaRESUMEN
Correlated response data arise often in biomedical studies. The generalized estimation equation (GEE) approach is widely used in regression analysis for such data. However, there are few methods available to check the adequacy of regression models in GEE. In this paper, a graphical method is proposed based on Cook and Weisberg's marginal model plot. A bootstrap method is applied to obtain the reference band to assess statistical uncertainties in comparing two marginal mean functions. We also propose using the generalized additive model (GAM) in a similar fashion. The proposed two methods are easy to implement by taking advantage of existing smoothing and GAM softwares for independent data. The usefulness of the methodology is demonstrated through application to a correlated binary data set drawn from a clinical trial, the Lung Health Study.
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Presentación de Datos , Modelos Estadísticos , Adulto , Terapia Conductista/métodos , Antagonistas Colinérgicos/administración & dosificación , Simulación por Computador , Humanos , Ipratropio/administración & dosificación , Persona de Mediana Edad , Estudios Multicéntricos como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Análisis de Regresión , Reproducibilidad de los Resultados , Cese del Hábito de Fumar/métodosRESUMEN
Many studies have quantified debris collected on beaches around the world. Only a few of those studies have been conducted in the United States, and they are largely limited to semi-quantitative efforts performed as part of volunteer clean-up activities. This study quantifies the distribution and composition of beach debris by sampling 43 stratified random sites on the Orange County, California coast, from August to September 1998. We estimated that approximately 106 million items, weighing 12 metric tons, occur on Orange County beaches. The most abundant items were pre-production plastic pellets, foamed plastics, and hard plastics. Debris density on the remote rocky shoreline was greater than that on high-use sandy beaches for most debris items. This finding partially reflects the periodic clean-up of high-use beaches by local municipalities, and also indicates that a high percentage of the observed debris was transported to the site from waterborne sources.
Asunto(s)
Monitoreo del Ambiente , Plásticos , Agua de Mar , Residuos , Contaminación del Agua/prevención & control , California , Monitoreo del Ambiente/métodos , HumanosRESUMEN
AIMS/HYPOTHESIS: Obesity is a complex trait influenced by multiple genes. We evaluated linkage in three regions of human chromosome 10 previously linked to obesity-related phenotypes. METHODS: We conducted non-parametric linkage analysis of obesity-related phenotypes in cohorts of 170 European-American and 43 African-American families having extremely obese and normal weight subjects. RESULTS: We found support for linkage of an obesity phenotype (BMI > or = 27 kg/m2) in both cohorts, as well as in a combined analysis (European-American cohort, Z = 1.90, p = 0.03; African-American cohort, Z = 2.25, p = 0.014; combined cohort, Z = 2.55, p = 0.005). CONCLUSION/INTERPRETATION: These results confirm previous reports of linkage in French and German families. The consistency of results across these four cohorts supports the localization of a quantitative trait locus influencing obesity to human chromosome region 10p12.