4,927 research outputs found
Effects of Ixeris Chinensis (Thunb.) Nakai boiling water extract on hepatitis B viral activity and hepatocellular carcinoma
Background: Hepatitis B virus (HBV) infection and hepatocellular carcinoma are major diseases that affect the Taiwanese population. Therefore, the development of an alternative herbal medicine that can effectively treat these diseases is a research target. In this study, we tested Ixeris Chinensis (Thunb.) Nakai boiling water extract (ICTN BWE) in vitro and analysed its effects on the HBV and liver cancer.Materials and Methods: We used a human liver cancer cell line (Hep3B, a cell line that continuously secretes HBV particles into a medium) as an experimental model for the screening of various ICTN BWE concentrations and their effects on the HBV in vitro.Results: Our results showed that 75 μg/mL ICTN BWE downregulated the relative expression of the hepatitis B virus surface antigens (HBsAg) to 77.1%. Using the human liver cancer cell lines HuH-7 and HepG2, and 3-(4,5- dimethylthiazol-zyl)-2,5-diphenyl tetrazolium bromide (MTT) and tumour clonogenic assays, we then showed that ICTN BWE inhibits hepatocellular carcinoma growth.Conclusion: Fluorescent microscopy of DAPI(4',6-Diamidino-2-phenylindole)-stained nuclei and DNA fragmentation assays confirmed the inhibitory effects of ICTN BWE on liver tumour cell growth through induction of apoptosis.Keywords: herbal medicine, Ixeris Chinensis (Thunb.) Nakai, antihepatocellular carcinoma, apoptosis, antihepatitis B viru
Microwave characterization of (Pb,La)TiO₃ thin films integrated on ZrO₂/SiO₂/Si wafers by sol-gel techniques
2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Self-organized Ge nanocrystals embedded in HfAlO fabricated by pulsed-laser deposition and application to floating gate memory
2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Enhanced insulin sensitivity associated with provision of mono and polyunsaturated fatty acids in skeletal muscle cells involves counter modulation of PP2A
International audienceAims/Hypothesis: Reduced skeletal muscle insulin sensitivity is a feature associated with sustained exposure to excess saturated fatty acids (SFA), whereas mono and polyunsaturated fatty acids (MUFA and PUFA) not only improve insulin sensitivity but blunt SFA-induced insulin resistance. The mechanisms by which MUFAs and PUFAs institute these favourable changes remain unclear, but may involve stimulating insulin signalling by counter-modulation/repression of protein phosphatase 2A (PP2A). This study investigated the effects of oleic acid (OA; a MUFA), linoleic acid (LOA; a PUFA) and palmitate (PA; a SFA) in cultured myotubes and determined whether changes in insulin signalling can be attributed to PP2A regulation. Principal Findings: We treated cultured skeletal myotubes with unsaturated and saturated fatty acids and evaluated insulin signalling, phosphorylation and methylation status of the catalytic subunit of PP2A. Unlike PA, sustained incubation of rat or human myotubes with OA or LOA significantly enhanced Akt-and ERK1/2-directed insulin signalling. This was not due to heightened upstream IRS1 or PI3K signalling nor to changes in expression of proteins involved in proximal insulin signalling, but was associated with reduced dephosphorylation/inactivation of Akt and ERK1/2. Consistent with this, PA reduced PP2Ac demethylation and tyrosine 307 phosphorylation-events associated with PP2A activation. In contrast, OA and LOA strongly opposed these PA-induced changes in PP2Ac thus exerting a repressive effect on PP2A.Conclusions/Interpretation: Beneficial gains in insulin sensitivity and the ability of unsaturated fatty acids to oppose palmitate-induced insulin resistance in muscle cells may partly be accounted for by counter-modulation of PP2A
Prognostic factor from MR spectroscopy in rat with astrocytic tumour during radiation therapy
Objective:
To investigate the relationship between the tumour volume and metabolic rates of astrocytic tumours using MR spectroscopy (MRS) during radiation therapy (RT).
Methods:
12 healthy male Sprague-Dawley® rats (Sprague–Dawley Animal Company, Madison, WI) were used, and a tumour model was created through injecting C6 tumour cells into the right caudate nuclei of the rats. Tumours grew for 18 days after the injection and before the imaging study and radiation treatment. MRS was performed with two-dimensional multivoxel point-resolved spectroscopy sequence using a GE Signa VH/i 3.0-T MR scanner (GE Healthcare, Milwaukee, WI) equipped with rat-special coil. RT was given on the 19th day with a dose of 4 Gy in one single fraction. The image examinations were performed before RT, and on the 4th, 10th, 14th and 20th days after treatment, respectively. GE FuncTool software package (GE Healthcare) was used for post-processing of spectrum.
Results:
Metabolic ratios of serial MRS decrease progressively with time after RT. Choline-containing components (Cho)/creatine and creatine phosphate (Cr) ratios immediately prior to RT differed significantly from those on the 10th, 14th and 20th days after RT; both Cho/N-acetyl aspartate (NAA) ratios and NAA/Cr ratios immediately prior to RT differed significantly from those on the 14th and 20th days after RT. A positive correlation between changes of tumour volume and changes of Cho/Cr, lipid and lactate/Cr and glutamate plus glutamine/Cr ratio was observed on the 4th day after RT.
Conclusion:
MRS provides potential in monitoring tumour response during RT, and the imaging biomarkers predict the response of astrocytic tumours to treatment.
Advances in knowledge:
MRS is combined with both tumour size and Ki-67 labelling index to access tumour response to radiation.ECU Open Access Publishing Support Fun
Multi-seeded melt growth (MSMG) of bulk Y-Ba-Cu-O using thin-film seeds
Y-Ba-Cu-O (YBCO) and Sm-Ba-Cu-O (SmBCO) thin films have been used for the
first time as heterogeneous seeds to multi-seed successfully the melt growth of
bulk YBCO in a multi-seeded melt growth (MSMG) process. The use of thin film
seeds, which may be prepared with highly controlled orientation (i.e. with a
well-defined a-b plane and precisely known a-direction), is based on their
superheating properties and reduces significantly contamination of the bulk
sample by the seed material. A variety of grain boundaries were obtained by
varying the angle between the seeds. Microstructural studies indicate that the
extent of residual melt deposited at the grain boundary decreases with
increasing grain boundary contact angle. It is established that the growth
front proceeds continuously at the (110)/(110) grain boundary without trapping
liquid, which leads to the formation of a clean grain boundary
Modulation of macrophage phenotype through controlled release of interleukin-4 from gelatine coatings on titanium surfaces
Pro-inflammatory phenotype (M1) macrophages initiate angiogenesis, while their prolonged activation can induce chronic inflammation. Anti-inflammatory phenotype (M2) macrophages promote vessel maturation and tissue regeneration. Biomaterials which can promote M2 polarisation after appropriate inflammation should enhance angiogenesis and wound healing. Herein, Interleukin-4 (IL-4), an anti-inflammatory cytokine, was adsorbed onto a titanium surface. Then, a genipin cross-linked gelatine hydrogel was coated onto the surface to delay IL-4 release. The cross-linking degree of the hydrogel was modulated by the different amount of genipin to control release of IL-4. When 0.7 wt% (weight %) genipin was used as a cross-linker, the sample (GG07-I) released less IL-4 within the first several days, followed by a sustained release time to 14 d. Meanwhile, the release rate of IL-4 in GG07-I reached a peak between 3 d and 7 d. In culture with macrophages in vitro, GG07-I and GG07 exhibited good cytocompatibility. The phenotypical switch of macrophages stimulated by the samples was determined by FACS, ELISA and PCR. Macrophages cultured with GG07-I, GG07 and PT were firstly activated to the M1 phenotype by interferon-gamma (IFN-γ). Then, due to the release of IL-4 in 5 to 7 d, GG07-I enhanced CD206, increased the secretion and gene expression of M2 marker, such as interleukin-10 (IL-10), arginase-1 (ARG-1) and platelet derived growth factor-BB (PDGF- BB). GG07-I prompted the switch from M1 to M2 phenotype. Those appropriate secretion of cytokines would benefit both vascularisation and osseointegration. Thus, the biomaterial directing inflammatory reaction has good prospects for clinical treatments
Environmental controls on the elemental composition of a Southern Hemisphere strain of the coccolithophore Emiliania huxleyi
A series of semi-continuous incubation experiments were conducted with the coccolithophore Emiliania huxleyi strain NIWA1108 (Southern Ocean isolate) to examine the effects of five environmental drivers (nitrate and phosphate concentrations, irradiance, temperature, and partial pressure of CO2 (pCO2)) on both the physiological rates and elemental composition of the coccolithophore. Here, we report the alteration of the elemental composition of E. huxleyi in response to the changes in these environmental drivers. A series of dose–response curves for the cellular elemental composition of E. huxleyi were fitted for each of the five drivers across an environmentally representative gradient. The importance of each driver in regulating the elemental composition of E. huxleyi was ranked using a semi-quantitative approach. The percentage variations in elemental composition arising from the change in each driver between present-day and model-projected conditions for the year 2100 were calculated. Temperature was the most important driver controlling both cellular particulate organic and inorganic carbon content, whereas nutrient concentrations were the most important regulator of cellular particulate nitrogen and phosphorus of E. huxleyi. In contrast, elevated pCO2 had the greatest influence on cellular particulate inorganic carbon to organic carbon ratio, resulting in a decrease in the ratio. Our results indicate that the different environmental drivers play specific roles in regulating the elemental composition of E. huxleyi with wide-reaching implications for coccolithophore-related marine biogeochemical cycles, as a consequence of the regulation of E. huxleyi physiological processes
Neutrino Mass, Sneutrino Dark Matter and Signals of Lepton Flavor Violation in the MRSSM
We study the phenomenology of mixed-sneutrino dark matter in the Minimal
R-Symmetric Supersymmetric Standard Model (MRSSM). Mixed sneutrinos fit
naturally within the MRSSM, as the smallness (or absence) of neutrino Yukawa
couplings singles out sneutrino A-terms as the only ones not automatically
forbidden by R-symmetry. We perform a study of randomly generated sneutrino
mass matrices and find that (i) the measured value of is well
within the range of typical values obtained for the relic abundance of the
lightest sneutrino, (ii) with small lepton-number-violating mass terms
for the right-handed sneutrinos, random
matrices satisfying the constraint have a decent probability of
satisfying direct detection constraints, and much of the remaining parameter
space will be probed by upcoming experiments, (iii) the terms radiatively generate appropriately small Majorana neutrino
masses, with neutrino oscillation data favoring a mostly sterile lightest
sneutrino with a dominantly mu/tau-flavored active component, and (iv) a
sneutrino LSP with a significant mu component can lead to striking signals of
e-mu flavor violation in dilepton invariant-mass distributions at the LHC.Comment: Revised collider analysis in Sec. 5 after fixing error in particle
spectrum, References adde
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