972 research outputs found

    Are published standards for haematological indices in pregnancy applicable across populations: an evaluation in healthy pregnant Jamaican women

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    <p>Abstract</p> <p>Background</p> <p>The haematological profile of the pregnant woman has an impact on the outcome of the pregnancy. Published guidelines indicate acceptable levels for haematological indices in pregnancy but they are population specific. Indicators of haemoglobin concentration are the most commonly utilized of the indices. These published international norms are used across populations, however, there is no evidence confirming their applicability to a population such as the Jamaican pregnant woman. This study was therefore undertaken with the intent of documenting the haematological profile of pregnant primigravid Jamaican women and comparing these to the established norms to determine whether the norms apply or whether there was a need to establish local norms.</p> <p>Methods</p> <p>This was a longitudinal study done on a cohort of 157 healthy primigravid women ages 15 to 25 and without anaemia, and who were recruited from the antenatal clinic of the University Hospital of the West Indies, Kingston, Jamaica. The haemoglobin concentration, packed cell volume, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, white blood cell count, red blood cell count and platelet count were measured on samples of blood obtained from each consenting participant during each of the three trimesters. The results were analysed using SPSS for windows (Version 11) and the data expressed as means ± S.D. Means were compared using the student's paired <it>t-test</it>. Comparison was then made with the international norms as recommended by the United States Center for Disease Control (1989). Ethical approval for this study was obtained from the University Hospital of the West Indies/University of the West Indies Ethics Committee.</p> <p>Results</p> <p>The results showed changes by trimester in all measured variables. For most of the indices the changes achieved levels of significance across trimesters. These changes were however in keeping with the expected physiological response in pregnancy and the values were similar to the published international norms.</p> <p>Conclusion</p> <p>The findings suggest that the international norms for haematological indices in pregnancy are applicable across populations and to the pregnant Jamaican primigravid woman. This finding may be reassuring to others with a similar population and stage of development as Jamaica.</p

    Increasing the sensitivity of terahertz split ring resonator metamaterials for dielectric sensing by localized substrate etching

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    We demonstrate a significant enhancement in the sensitivity of split ring resonator terahertz metamaterial dielectric sensors by the introduction of etched trenches into their inductive-capacitive gap area, both through finite element simulations and in experiments performed using terahertz time-domain spectroscopy. The enhanced sensitivity is demonstrated by observation of an increased frequency shift in response to overlaid dielectric material of thicknesses up to 18 μm deposited on to the sensor surface. We show that sensitivity to the dielectric is enhanced by a factor of up to ~2.7 times by the incorporation of locally etched trenches with a depth of ~3.4 μm, for example, and discuss the effect of the etching on the electrical properties of the sensors. Our experimental findings are in good agreement with simulations of the sensors obtained using finite element methods

    Children's vomiting following posterior fossa surgery: A retrospective study

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    <p>Abstract</p> <p>Background</p> <p>Nausea and vomiting is a problem for children after neurosurgery and those requiring posterior fossa procedures appear to have a high incidence. This clinical observation has not been quantified nor have risk factors unique to this group of children been elucidated.</p> <p>Methods</p> <p>A six year retrospective chart audit at two Canadian children's hospitals was conducted. The incidence of nausea and vomiting was extracted. Hierarchical multivariable logistic regression was used to quantify risk and protective factors at 120 hours after surgery and early vs. late vomiting.</p> <p>Results</p> <p>The incidence of vomiting over a ten day postoperative period was 76.7%. Documented vomiting ranged from single events to greater than 20 over the same period. In the final multivariable model: adolescents (age 12 to <17) were less likely to vomit by 120 hours after surgery than other age groups; those who received desflurane, when compared to all other volatile anesthetics, were more likely to vomit, yet the use of ondansetron with desflurane decre kelihood. Children who had intraoperative ondansetron were more likely to vomit in the final multivariable model (perhaps because of its use, in the clinical judgment of the anesthesiologist, for children considered at risk). Children who started vomiting in the first 24 hours were more likely to be school age (groups 4 to <7 and 7 to <12) and receive desflurane. Nausea was not well documented and was therefore not analyzed.</p> <p>Conclusion</p> <p>The incidence of vomiting in children after posterior fossa surgery is sufficient to consider all children requiring these procedures to be at high risk for POV. Nausea requires better assessment and documentation.</p

    Alpha-santalol, a chemopreventive agent against skin cancer, causes G2/M cell cycle arrest in both p53-mutated human epidermoid carcinoma A431 cells and p53 wild-type human melanoma UACC-62 cells

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    <p>Abstract</p> <p>Background</p> <p>α-Santalol, an active component of sandalwood oil, has shown chemopreventive effects on skin cancer in different murine models. However, effects of α-santalol on cell cycle have not been studied. Thus, the objective of this study was to investigate effects of α-santalol on cell cycle progression in both p53 mutated human epidermoid carcinoma A431 cells and p53 wild-type human melanoma UACC-62 cells to elucidate the mechanism(s) of action.</p> <p>Methods</p> <p>MTT assay was used to determine cell viability in A431 cells and UACC-62; fluorescence-activated cell sorting (FACS) analysis of propidium iodide staining was used for determining cell cycle distribution in A431 cells and UACC-62 cells; immunoblotting was used for determining the expression of various proteins and protein complexes involved in the cell cycle progression; siRNA were used to knockdown of p21 or p53 in A431 and UACC-62 cells and immunofluorescence microscopy was used to investigate microtubules in UACC-62 cells.</p> <p>Results</p> <p>α-Santalol at 50-100 μM decreased cell viability from 24 h treatment and α-santalol at 50 μM-75 μM induced G<sub>2</sub>/M phase cell cycle arrest from 6 h treatment in both A431 and UACC-62 cells. α-Santalol altered expressions of cell cycle proteins such as cyclin A, cyclin B1, Cdc2, Cdc25c, p-Cdc25c and Cdk2. All of these proteins are critical for G<sub>2</sub>/M transition. α-Santalol treatment up-regulated the expression of p21 and suppressed expressions of mutated p53 in A431 cells; whereas, α-santalol treatment increased expressions of wild-type p53 in UACC-62 cells. Knockdown of p21 in A431 cells, knockdown of p21 and p53 in UACC-62 cells did not affect cell cycle arrest caused by α-santalol. Furthermore, α-santalol caused depolymerization of microtubules similar to vinblastine in UACC-62 cells.</p> <p>Conclusions</p> <p>This study for the first time identifies effects of α-santalol in G<sub>2</sub>/M phase arrest and describes detailed mechanisms of G<sub>2</sub>/M phase arrest by this agent, which might be contributing to its overall cancer preventive efficacy in various mouse skin cancer models.</p

    Structure–activity relationships and the cytotoxic effects of novel diterpenoid alkaloid derivatives against A549 human lung carcinoma cells

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    The cytotoxicity of three alkaloids from the roots of Aconitum yesoense var. macroyesoense as well as 36 semi-synthetic C20-diterpenoid atisine-type alkaloid derivatives against A549 human lung carcinoma cells was examined. Ten acylated alkaloid derivatives, pseudokobusine 11-veratroate (9), 11-anisoate (12), 6,11-dianisoate (14), 11-p-nitrobenzoate (18), 11,15-di-p-nitrobenzoate (22), 11-cinnamate (25) and 11-m-trifluoromethylbenzoate (27), and kobusine 11-p-trifluoromethylbenzoate (35), 11-m-trifluoromethylbenzoate (36) and 11,15-di-p-nitrobenzoate (39), exhibited cytotoxic activity, and 11,15-dianisoylpseudokobusine (16) was found to be the most potent cytotoxic agent. Their IC50 values against A549 cells ranged from 1.72 to 5.44 μM. In the occurrence of cytotoxic effects of atisine-type alkaloids, replacement by an acyl group at both C-11 and C-15 resulted in the enhancement of activity of the parent alkaloids compared to that from having hydroxy groups at this position, and the presence of a hydroxy group at the C-6 position was required for the cytotoxic effects. These acylated alkaloid derivatives inhibit cell growth through G1 arrest

    Cellular Reactive Oxygen Species Inhibit MPYS Induction of IFNβ

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    Many inflammatory diseases, as well as infections, are accompanied by elevation in cellular levels of Reactive Oxygen Species (ROS). Here we report that MPYS, a.k.a. STING, which was recently shown to mediate activation of IFNβ expression during infection, is a ROS sensor. ROS induce intermolecular disulfide bonds formation in MPYS homodimer and inhibit MPYS IFNβ stimulatory activity. Cys-64, -148, -292, -309 and the potential C88xxC91 redox motif in MPYS are indispensable for IFNβ stimulation and IRF3 activation. Thus, our results identify a novel mechanism for ROS regulation of IFNβ stimulation

    MicroRNA-520b Inhibits Growth of Hepatoma Cells by Targeting MEKK2 and Cyclin D1

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    Growing evidence indicates that the deregulation of microRNAs (miRNAs) contributes to the tumorigenesis. We previously revealed that microRNA-520b (miR-520b) was involved in the complement attack and migration of breast cancer cells. In this report, we show that miR-520b is an important miRNA in the development of hepatocellular carcinoma (HCC). Our data showed that the expression levels of miR-520b were significantly reduced in clinical HCC tissues and hepatoma cell lines. We observed that the introduction of miR-520b dramatically suppressed the growth of hepatoma cells by colony formation assays, 5-ethynyl-2-deoxyuridine (EdU) incorporation assays and 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Moreover, ectopic expression of miR-520b was able to inhibit the growth of hepatoma cells in nude mice. Further studies revealed that the mitogen-activated protein kinase kinase kinase 2 (MEKK2) and cyclin D1 were two of direct target genes of miR-520b. Silencing of MEKK2 or cyclin D1 was able to inhibit the growth of hepatoma cells in vitro and in vivo, which is consistent with the effect of miR-520b overexpression on the growth of hepatoma cells. In addition, miR-520b significantly decreased the phosphorylation levels of c-Jun N-terminal kinase (p-JNK, a downstream effector of MEKK2) or retinoblastoma (p-Rb, a downstream effector of cyclin D1). In conclusion, miR-520b is able to inhibit the growth of hepatoma cells by targeting MEKK2 or cyclin D1 in vitro and in vivo. Our findings provide new insights into the role of miR-520b in the development of HCC, and implicate the potential application of miR-520b in cancer therapy

    f(R) theories

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    Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in Relativity, Published version, Comments are welcom
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