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1.
Multidrug resistance (MDR) is the result of overexpression of membrane bound proteins that efflux chemotherapeutic drugs from the cells. Two proteins, P-glycoprotein (P-gp) and multidrug-resistance associated protein-1 (MRP-1) efflux chemotherapeutic agents out of the cancer cell that decrease intracellular drug accumulation, thereby decreasing the effectiveness of many chemotherapeutic agents. In the present study, the ethanolic extract of the roots of Stemona curtisii Hook. was tested for the potential ability to modulate the MDR phenotype and function of P-gp and MRP-1. The S. curtisii extract reversed the resistance to putative chemotherapeutic agents, including vinblastine, paclitaxel and colchicine of KB-V1 cells (MDR human cervical carcinoma with high P-gp expression) in a dose-dependent manner, but not in KB-3-1 cells (drug sensitive human cervical carcinoma, which lack P-gp expression). The root extract also increased the intracellular uptake and retention of (3)[H]-vinblastine in KB-V1 cells dose dependently. The extract did not influence MDR phenotype-mediated MRP-1 in MRP1-HEK293 (human embryonic kidney cells stably transfected with pcDNA3.1-MRP1-H10 which show high MRP-1 expression) and pcDNA3.1-HEK293 (wild type). In summary, the S. curtisii root extract modulated P-gp activity but not MRP-1 activity. The result obtained from this study strongly indicated that S. curtisii extract may play an important role as a P-gp modulator as used in vitro and may be effective in the treatment of multidrug-resistant cancers. The purified form of the active components of S. curtisii extract should be investigated in more details in order to explain the molecular mechanisms involved in P-gp modulation. This is the first report of new biological activity in this plant, which could be a potential source of a new chemosensitizer. 相似文献
2.
Duangrat Tantikanlayaporn Patsorn Wichit Jittima Weerachayaphorn Arthit Chairoungdua Aporn Chuncharunee Apichart Suksamrarn Pawinee Piyachaturawat 《PloS one》2013,8(11)
Phytoestrogens have been implicated in the prevention of bone loss in postmenopausal osteoporosis. Recently, an active phytoestrogen from Curcuma comosa Roxb, diarylheptanoid (DPHD), (3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol, was found to strongly promote human osteoblast function in vitro. In the present study, we demonstrated the protective effect of DPHD on ovariectomy-induced bone loss (OVX) in adult female Sprague-Dawley rats with 17β-estradiol (E2, 10 µg/kg Bw) as a positive control. Treatment of OVX animals with DPHD at 25, 50, and 100 mg/kg Bw for 12 weeks markedly increased bone mineral density (BMD) of tibial metaphysis as measured by peripheral Quantitative Computed Tomography (pQCT). Histomorphometric analysis of bone structure indicated that DPHD treatment retarded the ovariectomy-induced deterioration of bone microstructure. Ovariectomy resulted in a marked decrease in trabecular bone volume, number and thickness and these changes were inhibited by DPHD treatment, similar to that seen with E2. Moreover, DPHD decreased markers of bone turnover, including osteocalcin and tartrate resistant acid phosphatase (TRAP) activity. These results suggest that DPHD has a bone sparing effect in ovariectomy-induced trabecular bone loss and prevents deterioration of bone microarchitecture by suppressing the rate of bone turnover. Therefore, DPHD appears to be a promising candidate for preserving bone mass and structure in the estrogen deficient women with a potential role in reducing postmenopausal osteoporosis. 相似文献
3.
Yoojin Park Duangrat Nim-anussornkul Tirayut Vilaivan Takashi Morii Byeang Hyean Kim 《Bioorganic & medicinal chemistry letters》2018,28(2):77-80
We have developed RNA-based quencher-free molecular aptamer beacons (RNA-based QF-MABs) for the detection of ATP, taking advantage of the conformational changes associated with ATP binding to the ATP-binding RNA aptamer. The RNA aptamer, with its well-defined structure, was readily converted to the fluorescence sensors by incorporating a fluorophore into the loop region of the hairpin structure. These RNA-based QF-MABs exhibited fluorescence signals in the presence of ATP relative to their low background signals in the absence of ATP. The fluorescence emission intensity increased upon formation of a RNA-based QF-MAB·ATP complex. 相似文献
4.
Khin Saw Aye Myint Anja Kipar Richard G. Jarman Robert V. Gibbons Guey Chuen Perng Brian Flanagan Duangrat Mongkolsirichaikul Yvonne Van Gessel Tom Solomon 《PLoS neglected tropical diseases》2014,8(8)
Background
Japanese encephalitis (JE) is a major cause of mortality and morbidity for which there is no treatment. In addition to direct viral cytopathology, the inflammatory response is postulated to contribute to the pathogenesis. Our goal was to determine the contribution of bystander effects and inflammatory mediators to neuronal cell death.Methodology/Principal Findings
Material from a macaque model was used to characterize the inflammatory response and cytopathic effects of JE virus (JEV). Intranasal JEV infection induced a non-suppurative encephalitis, dominated by perivascular, infiltrates of mostly T cells, alongside endothelial cell activation, vascular damage and blood brain barrier (BBB) leakage; in the adjacent parenchyma there was macrophage infiltration, astrocyte and microglia activation. JEV antigen was mostly in neurons, but there was no correlation between intensity of viral infection and degree of inflammatory response. Apoptotic cell death occurred in both infected and non-infected neurons. Interferon-α, which is a microglial activator, was also expressed by both. Tumour Necrosis Factor-α, inducible nitric oxide synthase and nitrotyrosine were expressed by microglial cells, astrocytes and macrophages. The same cells expressed matrix metalloproteinase (MMP)-2 whilst MMP-9 was expressed by neurons.Conclusions/Significance
The results are consistent with JEV inducing neuronal apoptotic death and release of cytokines that initiate microglial activation and release of pro-inflammatory and apoptotic mediators with subsequent apoptotic death of both infected and uninfected neurons. Activation of astrocytes, microglial and endothelial cells likely contributes to inflammatory cell recruitment and BBB breakdown. It appears that neuronal apoptotic death and activation of microglial cells and astrocytes play a crucial role in the pathogenesis of JE. 相似文献5.
Parntep Ratanakorn Anuwat Wiratsudakul Witthawat Wiriyarat Krairat Eiamampai Adrian H. Farmer Robert G. Webster Kridsada Chaichoune Sarin Suwanpakdee Duangrat Pothieng Pilaipan Puthavathana 《PloS one》2012,7(11)
Brown-headed gulls (Larus brunnicephalus), winter visitors of Thailand, were tracked by satellite telemetry during 2008–2011 for investigating their roles in the highly pathogenic avian influenza (HPAI) H5N1 virus spread. Eight gulls negative for influenza virus infection were marked with solar-powered satellite platform transmitters at Bang Poo study site in Samut Prakarn province, Thailand; their movements were monitored by the Argos satellite tracking system, and locations were mapped. Five gulls completed their migratory cycles, which spanned 7 countries (China, Bangladesh, India, Myanmar, Thailand, Cambodia, and Vietnam) affected by the HPAI H5N1 virus. Gulls migrated from their breeding grounds in China to stay overwinter in Thailand and Cambodia; while Bangladesh, India, Myanmar, and Vietnam were the places of stopovers during migration. Gulls traveled an average distance of about 2400 km between Thailand and China and spent 1–2 weeks on migration. Although AI surveillance among gulls was conducted at the study site, no AI virus was isolated and no H5N1 viral genome or specific antibody was detected in the 75 gulls tested, but 6.6% of blood samples were positive for pan-influenza A antibody. No AI outbreaks were reported in areas along flyways of gulls in Thailand during the study period. Distance and duration of migration, tolerability of the captive gulls to survive the HPAI H5N1 virus challenge and days at viral shedding after the virus challenging suggested that the Brown-headed gull could be a potential species for AI spread, especially among Southeast Asian countries, the epicenter of H5N1 AI outbreak. 相似文献
6.
Duangrat Satakhun Frédéric Gay Naruenat Chairungsee Poonpipope Kasemsap Pisamai Chantuma Sornprach Thanisawanyangkura Philippe Thaler Daniel Epron 《Ecological Research》2013,28(6):969-979
Natural rubber is a valuable source of income in many tropical countries and rubber trees are increasingly planted in tropical areas, where they contribute to land-use changes that impact the global carbon cycle. However, little is known about the carbon balance of these plantations. We studied the soil carbon balance of a 15-year-old rubber plantation in Thailand and we specifically explored the seasonal dynamic of soil CO2 efflux (F S) in relation to seasonal changes in soil water content (W S) and soil temperature (T S), assessed the partitioning of F S between autotrophic (R A) and heterotrophic (R H) sources in a root trenching experiment and estimated the contribution of aboveground and belowground carbon inputs to the soil carbon budget. A multiplicative model combining both T S and W S explained 58 % of the seasonal variation of F S. Annual soil CO2 efflux averaged 1.88 kg C m?2 year?1 between May 2009 and April 2011 and R A and R H accounted for respectively 63 and 37 % of F S, after corrections of F S measured on trenched plots for root decomposition and for difference in soil water content. The 4-year average annual aboveground litterfall was 0.53 kg C m?2 year?1 while a conservative estimate of belowground carbon input into the soil was much lower (0.17 kg C m?2 year?1). Our results highlighted that belowground processes (root and rhizomicrobial respiration and the heterotrophic respiration related to belowground carbon input into the soil) have a larger contribution to soil CO2 efflux (72 %) than aboveground litter decomposition. 相似文献
7.
Raungsomboon S Chidthaisong A Bunnag B Inthorn D Harvey NW 《Bioresource technology》2008,99(13):5650-5658
Pb2+ removal ability of the viable-freshwater cyanobacterium Gloeocapsa sp. was studied in batch experiments. Gloeocapsa sp. was cultured in the Medium 18 with pH adjusted to 3, 4, 5, 6 and 7. Growth was subsequently determined based on the increase of chlorophyll-a content. Gloeocapsa sp. was able to grow at all pH levels tested, except at pH 3. Removal of Pb2+ was then further studied under pH 4. The results showed that Pb2+ concentration in the range of 0–20 mg L−1 was not inhibitory to Gloeocapsa sp. growth but reduced its Pb2+ removal efficiency (by 4.5% when Pb2+ concentration increased from 2.5 to 20 mg L−1). Pb2+ removal characteristics followed the Langmuir adsorption isotherm with the maximum removal capacity (qmax) of 232.56 mg g−1. Adsorption of Pb2+ by this cyanobacterium followed the second order rate reaction and intraparticle diffusion was likely the rate-determining step. The initial rate of Pb2+adsorption during intraparticle diffusion was slower under light than under dark conditions, indicating that light probably slowed down the initial rate of intraparticle diffusion through the repulsion effects on cell membrane. 相似文献
8.
Bongkotrat Suyamud John Ferrier Laszlo Csetenyi Duangrat Inthorn Geoffrey Michael Gadd 《Environmental microbiology》2020,22(4):1588-1602
Struvite (magnesium ammonium phosphate-MgNH4PO4·6H2O), which can extensively crystallize in wastewater treatments, is a potential source of N and P as fertilizer, as well as a means of P conservation. However, little is known of microbial interactions with struvite which would result in element release. In this work, the geoactive fungus Aspergillus niger was investigated for struvite transformation on solid and in liquid media. Aspergillus niger was capable of solubilizing natural (fragments and powder) and synthetic struvite when incorporated into solid medium, with accompanying acidification of the media, and extensive precipitation of magnesium oxalate dihydrate (glushinskite, Mg(C2O4).2H2O) occurring under growing colonies. In liquid media, A. niger was able to solubilize natural and synthetic struvite releasing mobile phosphate (PO43−) and magnesium (Mg2+), the latter reacting with excreted oxalate resulting in precipitation of magnesium oxalate dihydrate which also accumulated within the mycelial pellets. Struvite was also found to influence the morphology of A. niger mycelial pellets. These findings contribute further understanding of struvite solubilization, element release and secondary oxalate formation, relevant to the biogeochemical cycling of phosphate minerals, and further directions utilizing these mechanisms in environmental biotechnologies such as element biorecovery and biofertilizer applications. 相似文献
9.
Wasana Chaisri Wim E. Hennink Chadarat Ampasavate Siriporn Okonogi 《AAPS PharmSciTech》2010,11(2):945-951
The aim of this study was to evaluate the effects of preparation method and the type of surfactant on the properties of cephalexin
(CPX) microspheres in order to obtain delivery systems suitable for the treatment of dairy mastitis. Microspheres were obtained
using various preparation conditions and their physicochemical characteristics such as size, loading efficiency, morphology,
and drug crystallinity were investigated. Antibacterial activity of microspheres from the optimum preparation condition was
also studied. CPX microspheres were prepared by two different W/O/W emulsion solvent evaporation methods using PLGA as a matrix
forming polymer. Several types of surfactants including nonionic, cationic, and anionic at different concentrations were used
for preparation of the particles. The type and concentration of surfactant did neither affect the size nor morphology of the
microspheres but showed a pronounced effect on the CPX encapsulation efficiency. It was found that Tween 80 showed the highest
drug encapsulation efficiency (66.5%). Results from X-ray diffraction diffractograms and differential scanning calorimetry
thermograms indicated that CPX entrapped in these microparticles was amorphous. Assessment of antibacterial activity showed
that the obtained CPX microspheres exhibited good inhibition with minimum inhibitory concentration and minimum bactericidal
concentration values of 128 μg/mL and 2,048 mg/mL against Staphylococcus aureus ATCC 25923, 512 μg/mL and 4,096 mg/mL against Escherichia coli ATCC 25922, respectively. 相似文献
10.
Delia Bethell David Saunders Anan Jongkaewwattana Jarin Kramyu Arunee Thitithayanont Suwimon Wiboon-ut Kosol Yongvanitchit Amporn Limsalakpetch Utaiwan Kum-Arb Nichapat Uthaimongkol Jean Michel Garcia Ans E. Timmermans Malik Peiris Stephen Thomas Anneke Engering Richard G. Jarman Duangrat Mongkolsirichaikul Carl Mason Nuanpan Khemnu Stuart D. Tyner Mark M. Fukuda Douglas S. Walsh Sathit Pichyangkul 《PloS one》2013,8(3)