3,075 research outputs found

    Effect of a 4-week weight maintenance diet on circulating hormone levels: implications for clinical weight loss trials

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    Summary The majority of weight loss studies fail to standardize conditions such as diet and exercise via a weight maintenance period prior to commencement of the trial. This study aimed to determine whether a weight stabilization period is necessary to establish stable baseline hormone concentrations. Fifty-one obese male participants with a body mass index of 30–40 kg m−2 and aged 25–54 years underwent 4 weeks on an energy balance diet that was designed to achieve weight stability. Blood samples were collected in the fasting state at commencement and completion of the 4-week period, and circulating concentrations of 18 commonly measured hormones were determined. During the 4-week weight maintenance period, participants achieved weight stability within −1.5 ± 0.2 kg (−1.4 ± 0.2%) of their initial body weight. Significant reductions in serum insulin (by 18 ± 6.5%) and leptin (by 21 ± 6.0%) levels occurred, but no significant changes were observed for gut-derived appetite-regulating hormones (ghrelin and peptide YY), nor thyroid, adrenal, gonadal or somatotropic hormones. There were no significant correlations between the change in body weight and the change in circulating concentrations of insulin or leptin over the 4-week period, indicating that the observed changes were not due to weight loss, albeit significant negative correlations were observed between the changes in body weight and plasma ghrelin and peptide YY levels. This study demonstrates the need for baseline weight maintenance periods to stabilize serum levels of insulin and leptin in studies specifically investigating effects on these parameters in the obese. However, this does not apply to circulating levels of gut-derived appetite-regulating hormones (ghrelin and peptide YY), nor thyroid, adrenal, gonadal or somatotropic hormones

    Four new neo-clerodane diterpenes from the stem bark of Croton oligandrus.

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    Four new neo-clerodanes, crotonolins C-F (3-6), were isolated from the stem bark of Croton oligandrus together with the known clerodane crotonzambefuran A, the abietanes 7-β-hydroxydehydroabietic acid and 7-oxodehydroabietic acid, and ferulic acid. Their structures were elucidated by spectroscopic analyses including 1D and 2D NMR and HRESIMS and by comparison with previously reported data. The cytotoxicity of the isolated compounds against A549, MCF7, PC3 and PNT2 cells was evaluated using the MTT assay. Only 7-β-hydroxydehydroabietic acid showed a moderate level of activity against PC3 cells with an IC50 value of 68.9 ± 6.6 μM

    Growth inhibitory activity of biflavonoids and diterpenoids from the leaves of the Libyan Juniperus phoenicea against human cancer cells

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    Three biflavonoids [cupressuflavone (1), amentoflavone (2)and sumaflavone (3)], four diterpenoids [13-epi-cupressic acid (4), imbricatholic acid (5), 3-hydroxy-sandaracopimaric acid (6)and dehydroabietic acid (7)]and onelignan [β-peltatin methyl ether (8)],were isolated from the cytotoxicfractions of the extracts of the leaves of the Libyan Juniperus phoeniceaL. The structures of these compounds were elucidated by spectroscopic means.Cytotoxicity of the compounds 1-6were assessedagainst the human lung cancer cell lineA549 using the MTT assay. Compounds 1and 3showed cytotoxicityagainst the A549cells(IC50= 65 µMand 77 µM, respectively), whereas, compound 2did not show any activity. Diterpenes4-6exhibited weak cytotoxicity against the A549 cells with the IC50values of 159 µM, 263 µMand 223 µM, respectively. The cytotoxicity of each compound was compared with the anticancer drug,etoposide (IC50=61 µM).Cupressuflavone (1)wasevaluatedalso for cytotoxicity against both the human PC3 cancer cell lineand the normal prostatecell line (PNT2), and this compoundrevealed a high degreeof cytotoxic selectivity towards the prostate cancer cells (PC3), with IC50value of 19.9 µM, without any evidence of cytotoxicity towards the normal prostatecell line(PNT2)

    Study protocol: Evaluation of the ‘Flavour School’ sensory food education programme: a cluster-randomised controlled trial in UK primary school children, aged 4-7 years, to determine impact on confidence and curiosity in tasting vegetables and fruit

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    Background Many children would benefit from a diet richer in vegetables and fruit. ‘Flavour School’ is a programme of ‘sensory food education’, which aims to increase children’s confidence and curiosity in exploring foods and flavours, especially vegetables and fruit. This study will conduct a cluster-randomised controlled trial to assess the outcomes of the Flavour School programme in primary school children aged 4–7 years. Methods Four hundred plus children from 4+ schools will either complete the Flavour School programme (experimental group) or have no intervention with normal school teaching (control group), cluster-randomised within-schools, by school class. Baseline data collection will consist of video recorded behavioural observation during a tasting activity, and post-intervention data collection will repeat this activity after the experimental group have completed the intervention. Process measures will be assessed using a teacher engagement feedback questionnaire. Discussion This study will provide causal data on the efficacy of a sensory food education intervention for increasing children’s confidence and curiosity in exploring foods and flavours, especially vegetables and fruit. This new knowledge will help educators and policy makers to make evidence based decisions on uptake of sensory food education

    Liquid chromatography mass spectrometry analysis and cytotoxicity of Asparagus adscendens roots against human cancer cell lines

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    Background: Asparagus adscendens Roxb. (Asparagaceae), is native to the Himalayas. This plant has been used in the prevention and effective treatment of various forms of cancers. Objective: This paper reports, for the first time, on the cytotoxicity of the methanol (MeOH) extract of the roots of A. adscendens and its solid‑phase extraction (SPE) fractions against four human carcinoma cell lines and LC‑ESI‑QTOF‑MS analysis of the SPE fractions. Materials and Methods: Finely powdered roots of A. adscendens were macerated in methanol and extracted through SPE using gradient solvent system (water: methanol) proceeded for analysis on LC‑ESI‑QTOF‑MS and cytotoxicity against four human carcinoma cell lines: breast (MCF7), liver (HEPG2), lung (A549), and urinary bladder (EJ138), using the 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazoliumbromide assay. Results: The MeOH extract and four SPE fractions exhibited cytotoxicity against all cell lines with the IC50 values ranging from 6 to 79 μg/mL. As observedin other Asparagus species, the presence of saponins and sapogenins in the SPE fractions was evident in the liquid chromatography‑mass spectrometry data. Conclusion: It is reasonable to assume that the cytotoxicity of the MeOH extract of the roots of A. adscendens and its SPE fractions, at least partly, due to the presence of saponins and their aglycones. This suggests that A. adscendens could be exploited as a potential source of cytotoxic compounds with putative anticancer potential

    Mechanically activated Piezo1 channels of cardiac fibroblasts stimulate p38 mitogen-activated protein kinase activity and interleukin-6 secretion

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    Piezo1 is a mechanosensitive cation channel with widespread physiological importance; however, its role in the heart is poorly understood. Cardiac fibroblasts help preserve myocardial integrity and play a key role in regulating its repair and remodeling following stress or injury. Here we investigated Piezo1 expression and function in cultured human and mouse cardiac fibroblasts. RT-PCR experiments confirmed that Piezo1 mRNA in cardiac fibroblasts is expressed at levels similar to those in endothelial cells. The results of a Fura-2 intracellular Ca2+ assay validated Piezo1 as a functional ion channel that is activated by its agonist, Yoda1. Yoda1-induced Ca2+ entry was inhibited by Piezo1 blockers (gadolinium and ruthenium red) and was reduced proportionally by siRNA-mediated Piezo1 knockdown or in murine Piezo1+/− cells. Results from cell-attached patch clamp recordings on human cardiac fibroblasts established that they contain mechanically activated ion channels and that their pressure responses are reduced by Piezo1 knockdown. Investigation of Yoda1 effects on selected remodeling genes indicated that Piezo1 activation increases both mRNA levels and protein secretion of IL-6, a pro-hypertrophic and profibrotic cytokine, in a Piezo1-dependent manner. Moreover, Piezo1 knockdown reduced basal IL-6 expression from cells cultured on softer collagen-coated substrates. Multiplex kinase activity profiling combined with kinase inhibitor experiments and phosphospecific immunoblotting established that Piezo1 activation stimulates IL-6 secretion via the p38 mitogen-activated protein kinase downstream of Ca2+ entry. In summary, cardiac fibroblasts express mechanically activated Piezo1 channels coupled to secretion of the paracrine signaling molecule IL-6. Piezo1 may therefore be important in regulating cardiac remodeling
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