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Cricothyroid membrane puncture and incision,the key techniques to save the lives of the patients in the Can't Intubate,Can't Oxygenate (CICO) emergency,need to be mastered by all the airway management staff.However,the decision to carry out cricothyroid membrane puncture or incision is often delayed due to the unfamiliarity with the adjacent anatomical structure of the cricothyroid membrane and the inability to accurately locate the cricothyroid membrane.As a result,serious complications and rescue failure occur.Therefore,airway management staff should be familiar with the adjacent structure and positioning methods of the cricothyroid membrane,so as to improve the success rate of emergency airway rescue,reduce complications,and protect the airway and life safety of the patients.
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Punções , Ferida Cirúrgica , HumanosRESUMO
The presence of benzothiazoles (BTHs) and organic ultraviolet filters (UV filters) in aquatic ecosystems has emerged as a significant environmental issue, requiring urgent and efficient determination methods. A new, rapid, and sensitive determination method using gas chromatography triple quadrupole mass spectrometer (GC-MS/MS) was developed for the simultaneous extraction and analysis of 10 commonly used BTHs and 10 organic UV filters in surface water, wastewater, sediment, and sludge. For aqueous samples, solid-phase extraction (SPE) method was employed with optimizing of SPE cartridge type, pH, and elution solvent. For solid samples, ultrasonic extraction-solid-phase extraction purification (UE-SPE) and pressurized liquid extraction (PLE) methods were compared. And extraction conditions for ultrasonic extraction method (extraction solvents and extraction times) and PLE method (extraction temperatures and extraction cycles) were optimized. The limits of quantification for the 20 target compounds in surface water and wastewater were 0.01-2.12 ng/L and 0.05-6.14 ng/L, while those for sediment and sludge with UE-SPE method were 0.04-5.88 ng/g and 0.22-6.61 ng/g, respectively. Among the 20 target compounds, the recoveries ranged from 70 to 130% were obtained for 16, 15, 15, and 15 analytes in the matrix-spiked samples of surface water, wastewater, sediment, and sludge with three levels, respectively. And the precision was also acceptable with relative standard deviation (RSD) below 20% for all analytes. The developed methods were applied for the determination and quantification of target compounds in surface water, sediment, wastewater, and sludge samples collected from two wastewater treatment plants (WWTPs) and the Pearl River in Guangzhou, China. BTHs were frequently detected in surface water and wastewater, while UV filters were mainly found in sediment and sludge. Benzotriazole (BT) and 2-hydroxybenzothiazole (2-OH-BTH) were the two major BTHs in influent wastewater and surface water, respectively, with concentrations up to 966 and 189 ng/L. As for sediment and sludge, 2-(2'-hydroxy-5'-octylphenyl)-benzotriazole (UV-329) was a predominant chemical, detected at concentrations of 111 and 151 ng/g, respectively.
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Esgotos , Poluentes Químicos da Água , Benzotiazóis/análise , Ecossistema , Cromatografia Gasosa-Espectrometria de Massas , Esgotos/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Águas Residuárias/análise , Água/química , Poluentes Químicos da Água/análiseRESUMO
In this study, total phosphorus (P) and P released forms were measured in core sediments from the areas affected by human settlement and shrimp farming activities and the core zone of the Can Gio Biosphere Reserve, a coastal district in south Vietnam. Furthermore, ecological risk assessment and parameters controlling P release from sediments were investigated, including pH, major elements (Al-Ca-Mg-Fe), and fine fraction. The average total amount of P in the sediments varied from 287 to 669 mg/kg, with significantly lower values being observed in the mangrove biosphere reserve area. According to the results of the correlation analysis, organic matter was the primary source of P in the sediments, but the majority of the P released was inorganic. Positive correlations were found between Fe and non-apatite inorganic P (NAIP) and apatite P (AP), as well as intercorrelations between P fractions (r = 0.40-0.79, p < 0.05), suggesting that Fe might be the controlling factor of P release in the investigated sediments. The rank orders of concentrations of P forms were significantly different between the areas. The range of P forms was AP (35-248 mg/kg) > NAIP (63-201 mg/kg) > LP (labile P) (4-25 mg/kg) in the human settlement and aquaculture areas and NAIP (84-99 mg/kg) > AP (20-38 mg/kg) > LP (7-12 mg/kg) in the mangrove biosphere reserve area. Risk assessment based on the total concentration of P and the availability of P from a single extraction suggested a relatively low risk of P from sediment as an internal load in the studied areas.
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Fósforo , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos/análise , Humanos , Fósforo/análise , Medição de Risco , Vietnã , Poluentes Químicos da Água/análiseRESUMO
5-methylbenzotriazole (5-TTri) and 5-chlorobenzotriazole (CBT) are two benzotriazole derivatives widely used in various industrial and domestic applications. This paper reports on the photochemical behaviour of 5-TTri and CBT in aqueous solutions under UV radiation at 254 nm and the influences of pH, salinity, metal species and humic acid (HA) on their photo-transformation processes. The photolysis of 5-TTri and CBT under the exposure to UV light were found to follow the first-order reaction kinetic in all cases with half-lives ranging from 7.1 h to 24.3 h for 5-TTri and 5.1 h-20.5 h for CBT in various aqueous solutions containing metal ions and HA. The photolysis rates for both 5-TTri and CBT were strongly dependent on the solution pH value, and decreased with increasing solution pH. Salinity, metal species Cu2+ and Fe3+, and especially HA had inhibitory effects on the photolysis of 5-TTri and CBT under UV light irradiation at 254 nm. We proposed the tentative photo transformation schemes for both 5-TTri and CBT, which involved two photoproducts (4-methylaniline and N, N-diethylaniline- p-toluidine) and three photoproducts (4-chloroaniline, Aniline and 2,6-diethylaniline), respectively, via N-N and N-NH bond scission and dechlorination process.
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Substâncias Húmicas , Poluentes Químicos da Água , Substâncias Húmicas/análise , Concentração de Íons de Hidrogênio , Fotólise , Salinidade , Raios Ultravioleta , Poluentes Químicos da Água/análiseRESUMO
From EtOAc-soluble fraction of the aerial parts of Ampelopsis cantoniensis (Vitaceae), two new meroterpenoids named ampechromonol A (1) and ampechromonol B (2), together with five known compounds (3-7), were isolated. Their structures were elucidated based on NMR spectroscopic analysis. The plausible biosynthesis pathway for the formation of two new meroterpenoids was proposed. This research is the first isolation of meroterpenoids from Ampelopsis genus. Compounds 1 and 2 showed weak cytotoxicity against MCF-7 breast cancer cells.
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Ampelopsis , Vitaceae , Estrutura Molecular , Componentes Aéreos da PlantaRESUMO
From an EtOAc-soluble fraction of the leaves of Azadirachta indica, two new 28-norlimonoids named nimbandiolactone-21 (1) and nimbandioloxyfuran (2), together with nimbandiolactone-23 (3), were isolated. Their relative structures were elucidated based on NMR spectroscopic interpretation and biosynthetic consideration. Nimbandioloxyfuran (2) and nimbandiolactone-23 (3) showed potent α-glucosidase inhibitory activity, with the IC50 values of 46.2 and 38.7 µM, respectively.
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Azadirachta/química , Limoninas/química , Folhas de Planta/química , Estrutura MolecularRESUMO
This paper presents the results of zeta potential, water contact angle, atomic force microscopy image, in vitro solubility, and content of heavy metals in polylactic acid (PLA)/chitosan (CS) nanoparticles loading nifedipine. In addition, the In Vivo test of the PLA/CS nanoparticles loading nifedipine in the mice is also one of highlights of this work. The Zeta potential result shows that the charged surface of the PLA/CS nanoparticles loading nifedipine is neutral, negative or complex depending on nifedipine content. Nifedipine plays a role in increase of hydrophobic property, swelling degree and regular surface as well as decrease of surface rough of the nanoparticles. The PLA/CS/nifedipine nanoparticles are dissolved in the solutions with pH 6.8, pH 4.5 and pH 1.2. The In Vivo test of PLA/CS nanoparticles loading nifedipine on mice was evaluated by the change in diastolic pressure, systolic pressure, arterial pressure and heart rate. The obtained results confirm that the PLA/CS nanoparticles loading nifedipine is suitable to apply in the treatment of hypertension patients lately.
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Bloqueadores dos Canais de Cálcio/administração & dosagem , Quitosana/química , Nanopartículas , Nifedipino/administração & dosagem , Poliésteres/química , Animais , Bloqueadores dos Canais de Cálcio/farmacocinética , Humanos , Camundongos , Nifedipino/farmacocinética , PolímerosRESUMO
This work presents a multi-step strategy to fabricate chitosan-derived nitrogen-doped carbon (CCS) and CCS/NiCo2O4 (CNCO) aerogels for supercapacitor application. The various mass fractions of NiCo precursors and chitosan as well as different carbonization temperatures, were investigated. The best rationally designed aerogel carbonized at 300⯰C (CNCO-2) had the highest specific surface area and nitrogen content. It exhibited a high capacitance of 1200â¯Fâ¯g-1 at 1.0 A g-1 as an active electrode material for supercapacitors. In addition, the fully solid-state CCS//CNCO-2 device had a high capacitance of 172â¯Fâ¯g-1 at 1.0 A g-1 and excellent cyclic stability (over 87â¯% capacitance retention after 10,000â¯cycles). This device displayed a maximum energy density of 53â¯Whâ¯kg-1 at 750â¯Wâ¯kg-1. Furthermore, two devices connected in series and parallel indicate typical voltage and capacitance expansion, highlighting practicable applications of chitosan-derived aerogel composites to meet different requirements in energy storage.
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BACKGROUND: The cost of health care in many countries is increasing rapidly. There is a growing interest in using machine learning for predicting high health care utilizers for population health initiatives. Previous studies have focused on individuals who contribute to the highest financial burden. However, this group is small and represents a limited opportunity for long-term cost reduction. OBJECTIVE: We developed a collection of models that predict future health care utilization at various thresholds. METHODS: We utilized data from a multi-institutional diabetes database from the year 2019 to develop binary classification models. These models predict health care utilization in the subsequent year across 6 different outcomes: patients having a length of stay of ≥7, ≥14, and ≥30 days and emergency department attendance of ≥3, ≥5, and ≥10 visits. To address class imbalance, random and synthetic minority oversampling techniques were employed. The models were then applied to unseen data from 2020 and 2021 to predict health care utilization in the following year. A portfolio of performance metrics, with priority on area under the receiver operating characteristic curve, sensitivity, and positive predictive value, was used for comparison. Explainability analyses were conducted on the best performing models. RESULTS: When trained with random oversampling, 4 models, that is, logistic regression, multivariate adaptive regression splines, boosted trees, and multilayer perceptron consistently achieved high area under the receiver operating characteristic curve (>0.80) and sensitivity (>0.60) across training-validation and test data sets. Correcting for class imbalance proved critical for model performance. Important predictors for all outcomes included age, number of emergency department visits in the present year, chronic kidney disease stage, inpatient bed days in the present year, and mean hemoglobin A1c levels. Explainability analyses using partial dependence plots demonstrated that for the best performing models, the learned patterns were consistent with real-world knowledge, thereby supporting the validity of the models. CONCLUSIONS: We successfully developed machine learning models capable of predicting high service level utilization with strong performance and valid explainability. These models can be integrated into wider diabetes-related population health initiatives.
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Heparin recently has been discovered as a novel anti-cancer agent. The combinations of heparin with other agents was reported not only to reduce the undesired effects of free heparin and increase the cellular uptake of the delivered molecules, but also is the basis for the design and development of multi-stimulation response systems to improve their killing cancer cell efficiency at the target positions. This study aimed to design a redox and pH dual-responsive anticancer system based on heparin for cisplatin (CPT) therapy. Heparin was first cross-linked with Poloxamer 407 chains via disulfide bridges to form a redox-sensitive system Hep-P407. CPT was then encapsulated into the Hep-P407 system via the complex of Platin and carboxyl groups to form the redox/pH-responsive system CPT@Hep-P407. The obtained Hep-P407 systems were proved and characterized using specific techniques including1H-NMR, zeta potential, Dynamic Light Scattering (DLS) and Fourier-transform infrared spectroscopy. The dual-responsive behavior to redox and pH of CPT@Hep-P407 was proved through DLS, zeta andin vitrorelease analysis meanwhile its cytotoxicity was investigated using Resazurin assay. The CPT@Hep-P407 system is expected to be a promising redox/pH-responsive anticancer system based on heparin for CPT therapy.
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Cisplatino , Heparina , Polietilenoglicóis , Polietilenoimina , Nanogéis , Heparina/química , Oxirredução , Concentração de Íons de Hidrogênio , Sistemas de Liberação de Medicamentos/métodosRESUMO
OBJECTIVE: To investigate whether the day of embryo transfer (day 2 or day 3) affects clinical pregnancy outcomes in poor responder patients. METHODS: We retrospectively analyzed the pregnancy rates of 265 initial fresh cycles of in vitro fertilization-embryo transfer (IVF-ET), all transferred on day 2 (n = 169) or day 3 (n = 96) irrespective of quality because of an extremely low number of available embryos. RESULTS: Among the poor responders aged < 35 years, a higher rate of clinical pregnancy was achieved in the day-3 than in the day-2 group (50% vs 32.43% ; RR = 0.65, 95% CI: 0.43 - 0.99), and among those aged years, the two groups showed similar pregnancy outcomes. CONCLUSION: Shortening the time of embryo culture has no obvious benefit for the pregnancy outcome. For the poor responders under 35 years of age, day-3 embryo transfer may afford an even higher rate of clinical pregnancy.
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Transferência Embrionária/métodos , Ovário/fisiologia , Resultado da Gravidez , Adulto , Feminino , Fertilização in vitro , Humanos , Gravidez , Taxa de Gravidez , Estudos RetrospectivosRESUMO
The distribution of elite soybean (Glycine max) cultivars is limited due to their highly sensitive to photoperiod, which affects the flowering time and plant architecture. The recent emergence of CRISPR/Cas9 technology has uncovered new opportunities for genetic manipulation of soybean. The major maturity gene E1 of soybean plays a critical role in soybean photoperiod response. Here, we performed CRISPR/Cas9-mediated targeted mutation of E1 gene in soybean cultivar Tianlong1 carrying the dominant E1 to investigate its precise function in photoperiod regulation, especially in plant architecture regulation. Four types of mutations in the E1 coding region were generated. No off-target effects were observed, and homozygous trans-clean mutants without T-DNA were obtained. The photoperiod sensitivity of e1 mutants decreased relative to the wild type plants; however, e1 mutants still responded to photoperiod. Further analysis revealed that the homologs of E1, E1-La, and E1-Lb, were up-regulated in the e1 mutants, indicating a genetic compensation response of E1 and its homologs. The e1 mutants exhibited significant changes in the architecture, including initiation of terminal flowering, formation of determinate stems, and decreased branch numbers. To identify E1-regulated genes related to plant architecture, transcriptome deep sequencing (RNA-seq) was used to compare the gene expression profiles in the stem tip of the wild-type soybean cultivar and the e1 mutants. The expression of shoot identity gene Dt1 was significantly decreased, while Dt2 was significantly upregulated. Also, a set of MADS-box genes was up-regulated in the stem tip of e1 mutants which might contribute to the determinate stem growth habit.
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BACKGROUND: Pokemon is a transcription repressor which plays a critical role in cell transformation and malignancy. However, little is known about its effect on the development and progression of hepatocellular carcinoma (HCC). The aim of this study was to investigate the expression of Pokemon in human HCC tissues and the biological behavior of Pokemon in HCC cells in which it is overexpressed. We also explored the expression of potential downstream cofactors of Pokemon. MATERIALS AND METHODS: Reverse transcription polymerase chain reaction and Western blot analysis were used to investigate the expression of Pokemon in tissues of 30 HCC patients. We then examined cell proliferation or apoptosis and ß-catenin or H-ras expression in Pokemon-depleted HepG(2) cells using DNA vector-based RNA interference technology. RESULTS: Pokemon was markedly expressed in 22/30 (73.3%) HCC tissues, with expression levels higher than in adjacent normal liver tissues (p < 0.05); expression is correlated with tumor size. In contrast, depletion of Pokemon inhibited proliferation of HepG(2) or induced apoptosis. Also, H-ras expression decreased to a large extent. CONCLUSIONS: Pokemon exerts its oncogenic activity in the development of HCC by promoting cancer cell growth and reducing apoptosis, and the effect may be mediated by H-ras.
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Apoptose/genética , Carcinoma Hepatocelular/genética , Proliferação de Células , Transformação Celular Neoplásica/genética , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica/genética , Genes ras/genética , Neoplasias Hepáticas/genética , Fatores de Transcrição/genética , Western Blotting , Carcinoma Hepatocelular/patologia , Transformação Celular Neoplásica/patologia , Feminino , Células Hep G2 , Humanos , Fígado/patologia , Neoplasias Hepáticas/patologia , Masculino , Invasividade Neoplásica , Estadiamento de Neoplasias , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Carga Tumoral , beta Catenina/genéticaRESUMO
Antibiotic resistance genes (ARGs) pose a serious threat to environmental biology and public health, along with the discharge and spread of wastewater. The advanced treatment of ARGs in wastewater therefore deserves special attention. In our previous study, we found that tidal flow constructed wetlands can effectively remove multiple ammonia from wastewater. In this study, we further optimized tidal flow constructed wetland systems by adding baffles and cultivating plants; we investigated the influence of process optimization on the removal of ARGs and the influence of functional microorganism distribution on nitrogen removal. The results show that the addition of baffles and plants can effectively improve the removal efficiency of ARGs, with the maximum removal rate of 21 resistance genes, in 7 categories, reaching 83.82%-100.0% with the simultaneous addition of baffles and plants. These removal rates were significantly higher than the increase resulting from a single baffle or plant group. From the comparison of the absolute abundance of ARGs in the substrate and plants, it is clear that the baffles can promote the enrichment of ARGs in the wetland substrate, while uptake by plants is also a way of removing ARGs. Combined with the results of nitrogen-cycle functional gene sequencing, system optimization can increase the diversity and richness of nitrification and denitrification functional microorganisms in the substrate, which is consistent with the higher removal rate of nitrification and total nitrogen in wastewater.
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Antibacterianos , Áreas Alagadas , Desnitrificação , Resistência Microbiana a Medicamentos/genética , Nitrificação , Nitrogênio , Eliminação de Resíduos Líquidos , Águas Residuárias/análiseRESUMO
From remaining aqueous fraction of the roots of Streptocaulon juventas, one new cardiac glycoside named periplogenin 3-O-ß-gentiobioside (1) together with six known ones (2-7) were isolated. Their relative structures were elucidated based on NMR spectroscopic analysis. Compound 1 showed moderate cytotoxicity against non-small cell lung carcinoma NCI-H460 and ovarian cancer HeLa cells. Moreover, compounds 2 and 3 exhibited remarkable cytotoxicity against NCI-H460 cell with the IC50 values of 0.34 and 0.068 µM, respectively.
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Apocynaceae/química , Cardenolídeos/isolamento & purificação , Raízes de Plantas/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Carcinoma Pulmonar de Células não Pequenas/patologia , Cardenolídeos/química , Cardenolídeos/farmacologia , Morte Celular/efeitos dos fármacos , Células HeLa , Humanos , Neoplasias Pulmonares/patologia , Células MCF-7 , Espectroscopia de Prótons por Ressonância MagnéticaRESUMO
The extensive usage of organic ultraviolet filters (UV filters) and benzothiazoles (BTs) has caused continuous and widespread pollution in the aquatic environment. This study investigated the occurrence of nine organic UV filters and eight BTs in the surface water and sediment of two major drinking water source rivers in the Pearl River Basin (PRB). The detection frequencies of six organic UV filters and seven BTs were above 50% in surface water, while eight target compounds were as high as 100%. Composition profiles revealed that 2-Hydroxybenzothiazole (2-OH-BTH, 1112 ng/L) and 2-Mercaptobenzothiazole (2-SH-BTH, 426.3 ng/L) were the predominant compounds in surface water, while Octyl 4-methoxycinnamate (OMC, maximum concentration, 68.3 ng/g) and UV-329 (18.8 ng/g) were predominant in sediment. Significant positive correlations were observed between water quality parameters (temperature, total phosphorus (TP) and total nitrogen (TN)) and organic UV filters (UV-327 and UV-P), indicating the domestic discharge. The calculated annual flux of targets compounds indicated that West River (WR) promoted more BTs and UV filters to the PRB than North River (NR) (BTs: WR22, 88,517 kg/year; NR13, 15,660 kg/year; UV filters: WR22, 28,332 kg/year; NR13, 1128 kg/year). Significant relationship between the Gross Domestic Product (GDP) and annual flux of BTs (R2 = 0.96, p < 0.001), and UV filters (R2 = 0.88, p < 0.001) in the rivers were found by regression analysis. UV-329 was detected with medium risk (RQ > 0.1) in all WR surface water samples, and 2-SH-BTH was detected with high risk (RQ > 1) in half of the WR sediment samples. This study provides the first time reports on the organic UV filters and BTs in two major rivers in the Pearl River Basin, and further showed that these two types of contaminants are ubiquitous and with potential risks in surface water and sediment of PRB.
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Rios , Poluentes Químicos da Água , Benzotiazóis , China , Monitoramento Ambiental , Água , Poluentes Químicos da Água/análiseRESUMO
A sodium-ethylenediamine graphite intercalation compound (Na(ethylenediamine)C15: "GIC") made from graphite flakes was used to study the microwave absorption performance of a GIC for the first time. Compared with the pristine graphite flakes, the neighboring layers in this GIC are pillared by Na(ethylenediamine)+ and possess a larger layer distance and improved electrical conductivity. Owing to the electrical conductivity of this GIC, only half of the loading content, compared to graphite flakes, is needed to achieve an outstanding absorption of -75.6 dB at 9.25 GHz (10.0 wt % GIC in paraffin in a 4.0 mm thick sample), but for graphite, 20.0 wt % is required for an absorption of -37.6 dB.
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Influenza vaccines administered intramuscularly exhibit poor mucosal immune responses in the respiratory tract which is the prime site of the infection. Intranasal vaccination is a potential route for vaccine delivery which has been demonstrated effective in inducing protective immune responses in both systemic and mucosal compartments. For this purpose, nanoparticles have been used as antigen delivery systems to improve antigen capture by immune cells. In this paper we demonstrate efficient delivery of viral antigens to airway epithelial cells, macrophages and dendritic cells, using polysaccharide nanoparticles (NPL), leading to a strong protection against influenza virus infection. A formulation combining split Udorn virus antigens with NPL and the mucosal protein adjuvant CTA1-DD was administered intranasally and resulted in an enhanced specific humoral immune response. Furthermore, NPL carrying split Udorn, with or without CTA1-DD, inhibited virus transmission from infected to uninfected naive mice. These results demonstrate that an intranasal delivery system combining NPL, mucosal adjuvant CTA1-DD and split virus antigens confers robust protection against influenza infection and inhibits virus transmission.
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Adjuvantes Imunológicos/administração & dosagem , Antígenos Virais/administração & dosagem , Toxina da Cólera/administração & dosagem , Portadores de Fármacos , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/administração & dosagem , Nanopartículas , Infecções por Orthomyxoviridae/prevenção & controle , Polissacarídeos/química , Proteínas Recombinantes de Fusão/administração & dosagem , Adjuvantes Imunológicos/química , Administração Intranasal , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/química , Antígenos Virais/imunologia , Toxina da Cólera/química , Toxina da Cólera/imunologia , Modelos Animais de Doenças , Composição de Medicamentos , Imunidade Humoral/efeitos dos fármacos , Vacinas contra Influenza/química , Vacinas contra Influenza/imunologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos DBA , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Porosidade , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/imunologiaRESUMO
OBJECTIVES: To investigate role of hypoxia inducible factor 1 (HIF-1) in the transcriptional activation of heat shock protein 70-2 (HSP70-2) in hepatocellular carcinoma (HCC) cells under hypoxic conditions. METHODS: HCC cells were exposed to reduced oxygen atmosphere (1% O2), or treated with YC-1 or HIF-1 alpha siRNA, the expression of HIF-1 alpha and HSP70-2 were detected by Western blot analysis. Serial deletions of the HSPA2 promoter were cloned in the reporter pGL3-Basic plasmid. These reporter plasmids were co-transfected with HIF-1 alpha siRNA, and the promoter activities were detected with the dual luciferase assay. RESULTS: Western blot analysis showed that both HIF-1 alpha and HSP70-2 proteins were strongly increased after HCC cells were exposed to hypoxic conditions (1% O2) for 6 h, and the expression level of HSP70-2 was increased in a time-dependent manner. Treatment of HepG2 cells with YC-1 or HIF-1 alpha siRNA significantly inhibited the expression of HIF-1 alpha and HSP70-2. In silico analysis of the HSP70-2 promoter using the Gene2 Promoter software revealed the presence of two putative hypoxic response element (HRE) consensus at -446bp (HRE1) and -238bp (HRE2). Depletion of promoter sequence between -653 and -385 led to a dramatic reduction of promoter activity, whereas further deletion to position -201 did not reduce the activity further. These data suggested that HRE1 plays an important role in hypoxia-induced activation of the HSPA2 promoter. Site-directed mutagenesis further confirmed these results. Mutation of HRE1 but not of HRE2 abrogated the sensitivity of the HSP70-2 promoter to hypoxia. CONCLUSIONS: HSP70-2 expression is up-regulated in response to hypoxia and a HIF-1 binding site (HRE1) in the HSP70-2 promoter is involved in this response.