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Water Method (water + method)
Selected AbstractsPrevotella intermedia lipopolysaccharide stimulates release of tumor necrosis factor-, through mitogen-activated protein kinase signaling pathways in monocyte-derived macrophagesFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2007Sung-Jo Kim Abstract The purpose of this study was to investigate the effects of lipopolysaccharide from Prevotella intermedia, a major cause of inflammatory periodontal disease, on the production of tumor necrosis factor (TNF)-, and the expression of TNF-, mRNA in differentiated THP-1 cells, a human monocytic cell line. The potential involvement of the three main mitogen-activated protein kinase (MAPK) signaling pathways in the induction of TNF-, production was also investigated. Lipopolysaccharide from P. intermedia ATCC 25611 was prepared by the standard hot phenol,water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. It was found that P. intermedia lipopolysaccharide can induce TNF-, mRNA expression and stimulate the release of TNF-, in differentiated THP-1 cells without additional stimuli. Treatment of the cells with P. intermedia lipopolysaccharide resulted in a simultaneous activation of three MAPKs [extracellular signal-related kinase 1/2 (ERK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2) and p38]. Pretreatment of the cells with MAPK inhibitors effectively suppressed P. intermedia lipopolysaccharide-induced TNF-, production without affecting the expression of TNF-, mRNA. These data thus provided good evidence that the MAPK signaling pathways are required for the regulation of P. intermedia lipopolysaccharide-induced TNF-, synthesis at the level of translation more than at the transcriptional level. [source] Measuring metabolic rate in the field: the pros and cons of the doubly labelled water and heart rate methodsFUNCTIONAL ECOLOGY, Issue 2 2004P. J. Butler Summary 1Measuring the metabolic rate of animals in the field (FMR) is central to the work of ecologists in many disciplines. In this article we discuss the pros and cons of the two most commonly used methods for measuring FMR. 2Both methods are constantly under development, but at the present time can only accurately be used to estimate the mean rate of energy expenditure of groups of animals. The doubly labelled water method (DLW) uses stable isotopes of hydrogen and oxygen to trace the flow of water and carbon dioxide through the body over time. From these data, it is possible to derive a single estimate of the rate of oxygen consumption () for the duration of the experiment. The duration of the experiment will depend on the rate of flow of isotopes of oxygen and hydrogen through the body, which in turn depends on the animal's size, ranging from 24 h for small vertebrates to up to 28 days in Humans. 3This technique has been used widely, partly as a result of its relative simplicity and potential low cost, though there is some uncertainty over the determination of the standard error of the estimate of mean . 4The heart rate (fH) method depends on the physiological relationship between heart rate and . 5If these two quantities are calibrated against each other under controlled conditions, fH can then be measured in free-ranging animals and used to estimate . 6The latest generation of small implantable data loggers means that it is possible to measure fH for over a year on a very fine temporal scale, though the current size of the data loggers limits the size of experimental animals to around 1 kg. However, externally mounted radio-transmitters are now sufficiently small to be used with animals of less than 40 g body mass. This technique is gaining in popularity owing to its high accuracy and versatility, though the logistic constraint of performing calibrations can make its use a relatively extended process. [source] Atrazine-induced changes in aromatase activity in estrogen sensitive target tissuesJOURNAL OF APPLIED TOXICOLOGY, Issue 3 2008A. C. Holloway Abstract Atrazine (ATR) is a pesticide used widely throughout North America. Although not directly estrogenic, ATR treatment has been shown to increase aromatase activity in tumor cell lines. Thus, it is suggested that ATR can increase local tissue estrogen levels in estrogen sensitive target tissues through increased aromatase activity. Therefore the effect of ATR on aromatase activity was measured in human granulosa-lutein cell cultures, cells that abundantly express aromatase, and endometrial stromal cell (ESC) cultures, cells that do not express aromatase. Aromatase activity was quantified by the tritiated water method and the specificity of the assay was confirmed by co-incubation with 4-hydroxyandrostenedione, an irreversible inhibitor of the catalytic activity of aromatase. Aromatase activity in ATR treated (1,10 µm) granulosa-lutein cells was increased more than 2-fold compared with control cultures. There were no treatment related changes in cellular protein and thus it is suggested that the ATR-induced change in aromatase activity was not due to an increase in cell number. ATR-treatment had no effect on ESC aromatase activity at any concentration tested. Similarly, there was no effect of ATR treatment on human recombinant aromatase activity in our cell-free test system. Therefore it is concluded that µm concentrations of ATR can increase aromatase activity of human granulosa cells but not ESC and this effect is not elicited at the enzyme level. Copyright © 2007 John Wiley & Sons, Ltd. [source] Daily energy expenditure of singing great reed warblers Acrocephalus arundinaceusJOURNAL OF AVIAN BIOLOGY, Issue 4 2008Dennis Hasselquist According to honest signalling theory, signals must be costly to produce to retain information about the signaller's quality. The song produced by male birds during breeding is a vocal "ornament" used for intra- and inter-sexual purposes. The energetic cost of this vocal signal remains a contentious issue. We used the doubly labelled water method to measure field metabolic rate by estimating CO2 production and then convert this to daily energy expenditure (DEE) in great reed warbler males singing under natural conditions (10 at low to moderate intensity and 7 at very high intensity from dawn to dusk). There was a significant positive relationship between singing intensity and DEE. From this relationship we extrapolated the average DEE for intensely singing males (i.e., males producing song sounds 50% of the time and hence sitting at their elevated song post in the top of a reed stem more or less continuously throughout the ,20 h of daylight) to 3.3×BMR (basal metabolic rate) and for non-singing males to 2.2×BMR. The mean DEE measured for the seven males singing with very high intensity was 3.1×BMR. The maximum measured DEE for a single male was 3.9×BMR, i.e. close to the maximum sustainable DEE (4×BMR), and the minimum DEE was 2.1×BMR for a male singing at very low intensity. These results imply that producing intensive advertising song in birds may incur a substantial cost in terms of increased energy expenditure. [source] Doubly labelled water for the measurement of total energy expenditure in man , progress and applications in the last decadeNUTRITION BULLETIN, Issue 2 2008L. J. C. Bluck Summary The doubly labelled water method for the measurement of total energy expenditure is a methodology that is still maturing. Over the last 10 years, the number of publications describing its exploitation in man has remained roughly constant, at a rate of about 50 per annum. During this time, the laboratory techniques used have become more refined, particularly in the measurement of deuterium enrichment. This article details the methodological advances which have been made and presents a brief review of some recent applications. [source] Assessment of Infant Feeding: The Validity of Measuring Milk IntakeNUTRITION REVIEWS, Issue 8 2002Kelley S. Scanlon Ph.D., R.D. Accurate assessment of infant feeding is needed for clinical practice and research. We identified 32 studies that evaluated the validity of direct observation, test weighing, or doubly labeled water methods. Correlations with validation standards were highest for doubly labeled water and test weighing, and lowest for observation. Cost and availability of isotope may limit the doubly labeled water method to research studies, whereas observation may be useful for clinical practice. Test weighing could be applied to either setting, but it may be practical to sample less frequently over 24 hours. Validity results and intended use of the measurement should be considered when selecting a method. [source] Year-round high physical activity levels in agropastoralists of Bolivian Andes: Results from repeated measurements of DLW method in peak and slack seasons of agricultural activitiesAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2009Hiroshi Kashiwazaki By the repeated use of the doubly labeled water method (DLW), this study aimed to investigate (1) the extent of changes in energy expenditure and physical activity level (PAL) in response to increased agricultural work demands, and (2) whether the seasonal work demands induce the changes in the fairly equitable division of work and similarity of energy needs between men and women observed in our previous study (Phase 1 study; Kashiwazaki et al., 1995: Am J Clin Nutr 62: 901,910). In a rural small agropastoral community of the Bolivian Andes, we made the follow-up study (Phase 2, 14 adults; a time of high agricultural activity) of the Phase 1 study (12 adults; a time of low agricultural activity). In the Phase 2 study, both men and women showed very high PAL (mean±SD), but there was no significant difference by sex (men; 2.18 ± 0.23 (age; 64 ± 11 years, n = 7), women; 2.26 ± 0.25 (63 ± 10 years, n = 7)). The increase of PAL by 11% (P = 0.023) in the Phase 2 was equally occurred in both men and women. The factorial approach underestimated PAL significantly by ,15% (P < 0.05). High PAL throughout the year ranging on average 2.0 and 2.2 was attributable to everyday tasks for subsistence and domestic works undertaking over 9,11 h (men spent 2.7 h on agricultural work and 4.7 h on animal herding, whereas women spent 7.3 h almost exclusively on animal herding). The seasonal increase in PAL was statistically significant, but it was smaller than those anticipated from published reports. A flexible division of labor played an important role in the equitable energetic increase in both men and women. Am. J. Hum. Biol., 2009. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||