Gambogenic Acid Inhibits Basal Autophagy of Drug-Resistant Hepatoma Cells and Improves Its Sensitivity to Adriamycin.

Gambogenic acid (GNA) is extracted from plant Gamboge, has a wide range of anti-tumor effects. In this paper, we study the inhibitory effect of GNA on the BEL-7402/ADM of hepatoma resistant cell lines and further study the mechanism of action. Cell viability test represented that GNA could improve the sensitivity of hepatoma drug-resistant cell line BEL-7402/ADM to Adriamycin (ADM), and further study by 4',6-diamidino-2-phenylindole (DAPI) staining and flow cytometry found that GNA could improve the effect of ADM on promoting apoptosis in BEL-7402/ADM cells, and the activation of apoptosis-related protein was significantly increased, and the ratio of Bax to Bcl-2 was significantly increased. Monodansylcadaverine staining and transmission electron microscopy showed that the basal autophagy level of BEL-7402/ADM cells was higher than that of BEL-7402 cells. Further detection of protein expression found that the intracellular LC3-II to LC3-I ratio and Beclin 1 protein expression increased in the combination of GNA and ADM, but the protein level of p62 increased significantly. GNA inhibit protective autophagy in BEL-7402/ADM cells and promote the role of ADM in inducing apoptosis, thereby increasing ADM sensitivity to BEL-7402/ADM cells, and the effect of GNA inhibition of autophagy may be achieved by inhibiting the degradation of autophagosomes.

Bioaccessibility and bioavailability adjusted dietary exposure of cadmium for local residents from a high-level environmental cadmium region.

The critical health risks caused by cadmium (Cd) via dietary exposure are commonly assessed by detecting Cd concentrations in foods. Differently, in this study, the bioaccessibility and bioavailability of Cd in major local harvests were introduced to assess the dietary exposure of local residents from a high-level environmental Cd region. The results indicated that certain Cd was released into the digestive juice after in vitro digestion with a bioaccessibility of 20-63% for rice and 3-32% for leafy vegetables, and the released portion was partially absorbed by Caco-2 cells with a bioavailability of 2-21% for rice and 0.2-13% for leafy vegetables. The results obtained from the toxicokinetic model revealed that the predicted urinary Cd values from the estimated daily intake (EDI) of Cd, which accounted for bioaccessibility and bioavailability, were consistent with the actual measured values, and the EDIs were considerably lower than the acceptable daily intake. This suggests that the bioaccessibility and bioavailability adjusted dietary Cd exposure should be more precise. The key issues addressed in our study implores that a potential health risk cannot be neglected in people with high consumption of rice from high-level zone.

Isolation and expression of four Megalobrama amblycephala toll-like receptor genes in response to a bacterial infection.

Toll-like receptors (TLRs) are a category of pattern recognition receptors (PRRs), which recognize pathogen associated molecular patterns (PAMPs) and participate in the immune responses. We identified tlr5a, tlr5b, tlr9 and tlr21 from the genome of blunt snout bream (Megalobrama amblycephala). All four tlrs were constitutively expressed in all examined tissues. After an immune bacterial challenge with Aeromonas hydrophila, their expressionwas up-regulated in lymphoid organs and tissues. Recombinant eukaryotic plasmid pEGFP-N1 was transfected into the common carp (Cyprinus carpio) EPC (epithelioma papulosum cyprini) cells for the purpose of subcellular localization. pcDNA3.1(+) recombinant eukaryotic plasmid was used to investigate the effects of overexpression of tlrs on the expression of downstream interferon-associated immune factors. The four Tlrs were distributed in the cytoplasm of transfected cells and appeared as filamentous or reticular. The expression of irf3, irf7, isg15, mx1, pkr and viperin at 0, 6, 12, 18, 24, 36, 48 and 72 h post-transfection in transfected EPC cells was quantified by qPCR. Overexpression of tlrs upregulated the expression of viperin, isg15, irf3, irf7, mx1 and pkr (in that order of magnitude). We also cloned the following promoters of irfs: Irf1-p, irf2-p, irf6-p, irf7-p, irf8-p and irf9-p. Results of the dual luciferase reporter assay suggested that tlr5a, tlr5b and tlr9 enhanced the activities of irf7-p, while tlr5b enhanced the activities of irf1-p and irf7-p. This suggests that they all play a role in the innate immunity. The experiments also indicated that TLRs activate irf3 or irf7 signaling to induce IFN secretion and subsequent upregulation of IFN-stimulated genes. These results indicate that tlrs and irfs play an important immune role in response to A. hydrophila infection in blunt snout bream, and pave the way for further studies of immune mechanisms mediated by TLRs in fish.

Identification, characterization and expression in response to Aeromonas hydrophila challenge of five interferon regulatory factors in Megalobrama amblycephala.

Interferon regulatory factor (Irf) family represents one of the most important transcription factor families, with multiple biological roles. In this study, we characterized five Irf family members (irf4a, irf4b, irf6, irf8 and irf10) in Megalobrama amblycephala at the cDNA and (predicted) amino acid levels, analyzed them phylogenetically, and developed gene-specific primers for qPCR analysis. All five irfs were constitutively expressed in all examined tissues, but their transcription was significantly higher in lymphoid organs and tissues, such as kidney, spleen and intestine. Exceptions were irf8, which was expressed at a high level in heart and brain tissues, and irf6, expressed at low levels in most tissues. After a bacterial immune challenge with Aeromonas hydrophila, the expression of irfs in liver was up-regulated: mairf4a 8.12-fold, mairf4b 29.9-fold, mairf6 1.38-fold and mairf10 1.65-fold (mairf8 was an exception: 0.07-fold). In spleen, kidney, intestine and gills, transcript levels of studied irfs increased only at specific time-points. The results suggested that irfs are involved in the immune response to bacterial infection in M. amblycephala, which will help elucidate the biological functions of irfs in the immune system of teleost fish.

Evaluation of Skin Deformation Tactile Feedback for Teleoperated Surgical Tasks.

During interaction with objects using a tool, we experience force and tactile feedback. One form of tactile feedback is local fingerpad skin deformation. In this paper, we provide haptic feedback to users of a teleoperation system through a skin deformation tactile feedback device. The device is able to provide tangential and normal skin deformation in a coupled manner, and is designed so that users can grasp it with a precision grip using multiple fingerpads. By applying skin deformation feedback on multiple fingerpads, the device is able to provide multi-degree-of-freedom interaction force direction and magnitude information to the user. To evaluate the effectiveness of this approach for the performance of teleoperated manipulation tasks, we performed a study in which 20 participants used a teleoperation system to perform one of two manipulation tasks (peg transfer and tube connection) using force feedback, skin deformation feedback, and the combination of both feedback. Results showed that participants are able to use all feedback to improve task performance compared to the case without haptic feedback, although the degree of improvement depended on the nature of the task. The feedback also improved situation awareness, felt consistent with prior experience, and did not affect concentration on the task, as reported by participants.

Expression and functional characterization of interferon regulatory factors (irf2, irf7 and irf9) in the blunt snout bream (Megalobrama amblycephala).

Interferon regulatory factors (irfs) are a family of genes that encode transcription factors with important roles in regulating the expression of Type I interferons (IFNs) and other genes associated with related pathways. irfs have multitudinous functions in growth, development and regulation of oncogenesis. In this study, three irf family members (irf2, irf7, irf9) were identified and characterized in Megalobrama amblycephala at the mRNA and amino acid levels. M. amblycephala irfs share a high sequence homology with other vertebrate irfs. Constitutive expression levels of the three genes were detected (using qPCR) in all studied tissues: low to medium in kidney, gills, heart and muscle, and high in liver, spleen, intestine and blood. qPCR was also used to analyze the dynamic expression patterns of irfs in different embryonic development stages: irf2 is not activated during the embryonic development, whereas irf9 appears to play important roles around hatching and during the larval development. Transcripts of all three studied irfs were upregulated after stimulation by Aeromonas hydrophila bacterium in liver, spleen, head kidney and trunk kidney, whereas downregulation was observed in intestine and gills. The results show that these three irfs are likely to be important factors in the blunt snout bream immune system. They also provide a foundation for studying the origin and evolution of the innate immune system in the blunt snout bream.

Molecular characterization and immunological response analysis of toll-like receptors from the blunt snout bream (Megalobrama amblycephala).

The innate immunity serves as the primary line of defense against pathogen invasion. Toll-like receptors (TLRs) play a pivotal role in the innate immunity by sensing specific pathogen-associated molecular patterns and activating immune responses. In this study, 14 TLRs (TLR1, 2, 3, 4, 5, 7, 8a, 8b, 9, 18, 19, 20, 21 and 22) were identified and characterized in a cyprinid fish Megalobrama amblycephala. A majority of MaTLRs possessed the typical structural features of the TLR protein family: LRR domain, TM region and TIR domain. Phylogenetic analyses confirmed the existence of six TLR families and revealed close relationships with other cyprinid orthologs. All TLRs were constitutively expressed in all eight examined tissues. After Aeromonas hydrophila challenge, the expression profiles of MaTLR mRNAs were analyzed in liver, spleen and head kidney: MaTLR1, 2, 5, 9, 21 and 22 were up-regulated, MaTLR3, 7, 8a, 8b and 19 were down-regulated, and MaTLR4, 18 and 20 expression patterns varied among tissues. These results indicate that most of MaTLRs are likely to be involved in the immune responses against bacterial infection.

Molecular identification and functional characterisation of the interferon regulatory factor 1 in the blunt snout bream (Megalobrama amblycephala).

Interferon regulatory factors (IRFs) play a key role in mediating the host response against pathogen infection and other important biological processes. This is the first report of an IRF family member in blunt snout bream Megalobrama amblycephala. The complete cDNA of M. amblycephala (Ma) IRF1 gene has 1422 nucleotides (nt.), with an open reading frame of 858 nt, encoding a polypeptide of 285 amino acids. The putative MaIRF1 polypeptide shared significant structural homology with known IRF1 homologs: a conserved IRF domain was found at the N-terminal and an IRF association domain 2 at the C-terminal. Phylogenetic analysis showed that MaIRF1 amino acid sequence clustered with other teleost IRF1s, with a grass carp ortholog exhibiting the highest similarity. MaIRF1 mRNA expression patterns were studied using quantitative real-time PCR in healthy fish tissues and after a challenge with Aeromonas hydrophila bacterium. It was constitutively expressed in all examined tissues: the highest in blood, the lowest in muscle. The expression after A. hydrophila challenge was up-regulated in liver, spleen and kidney, but down-regulated in intestine and gills. At the protein level, similar expression patterns were observed in liver and gills. Patterns differed in intestine (up-regulation), spleen (down-regulation) and kidney (expression mostly unchanged). This study indicates that MaIRF1 gene plays an important role in the blunt snout bream immune system, hence providing an important base for further studies.

A new stent with streamlined cross-section can suppress monocyte cell adhesion in the flow disturbance zones of the endovascular stent.

We proposed a new stent with streamlined cross-sectional wires, which is different from the clinical coronary stents with square or round cross-sections. We believe the new stent might have better hemodynamic performance than the clinical metal stents. To test the hypothesis, we designed an experimental study to compare the performance of the new stent with the clinical stents in terms of monocyte (U-937 cells) adhesion. The results showed that when compared with the clinical stents, the adhesion of U-937 cells were much less in the new stent. The results also showed that, when Reynolds number increased from 180 (the rest condition for the coronary arteries) to 360 (the strenuous exercise condition for the coronary arteries), the flow disturbance zones in the clinical stents became larger, while they became smaller with the new stent. The present experimental study therefore suggests that the optimization of the cross-sectional shape of stent wires ought to be taken into consideration in the design of endovascular stents.

Design of an Optically Controlled MR-Compatible Active Needle.

An active needle is proposed for the development of magnetic resonance imaging (MRI)-guided percutaneous procedures. The needle uses a low-transition-temperature shape memory alloy (LT SMA) wire actuator to produce bending in the distal section of the needle. Actuation is achieved with internal optical heating using laser light transported via optical fibers and side coupled to the LT SMA. A prototype, with a size equivalent to a standard 16-gauge biopsy needle, exhibits significant bending, with a tip deflection of more than 14° in air and 5° in hard tissue. A single-ended optical sensor with a gold-coated tip is developed to measure the curvature independently of temperature. The experimental results in tissue phantoms show that human tissue causes fast heat dissipation from the wire actuator; however, the active needle can compensate for typical targeting errors during prostate biopsy.

Influence of proximal drug eluting stent (DES) on distal bare metal stent (BMS) in multi-stent implantation strategies in coronary arteries.

The aim of this study was to investigate the drug distribution in arteries treated with DES-BMS stenting strategy and to analyze the influence of proximal DES on distal segments of BMS. A straight artery model (Straight Model) and a branching artery model (Branching Model) were constructed in this study. In each model, the DES was implanted at the proximal position and the BMS was implanted distally. Hemodynamic environments, drug delivery and distribution features were simulated and analyzed in each model. The results showed that blood flow would contribute to non-uniform drug distribution in arteries. In the Straight Model the proximal DES would cause drug concentration in BMS segments. While in the Branching Model the DES in the main artery has slight influence on the BMS segments in the branch artery. In conclusion, due to the blood flow washing effect the uniformly released drug from DES would distribute focally and distally. The proximal DES would have greater influence on the distal BMS in straight artery than that in branching artery. This preliminary study would provide good reference for atherosclerosis treatment, especially for some complex cases, like coronary branching stenting.

Sensory Substitution and Augmentation Using 3-Degree-of-Freedom Skin Deformation Feedback.

During tool-mediated interaction with everyday objects, we experience kinesthetic forces and tactile sensations in the form of vibration and skin deformation at the fingerpad. Fingerpad skin deformation is caused by forces applied tangentially and normally to the fingerpad skin, resulting in tangential and normal skin displacement. We designed a device to convey 3-degree-of-freedom (DoF) force information to the user via skin deformation, and conducted two experiments to determine the devices effectiveness for force-feedback substitution and augmentation. For sensory substitution, participants used 1-DoF and 3-DoF skin deformation feedback to locate a feature in a 3-DoF virtual environment. Participants showed improved precision and shorter completion time when using 3-DoF compared to 1-DoF skin deformation feedback. For sensory augmentation, participants traced a path in space from an initial to a target location, while under guidance from force and/or skin deformation feedback. When force feedback was augmented with skin deformation, participants reduced their path-following error over the cases when force or skin deformation feedback are used separately. We conclude that 3-DoF skin deformation feedback is effective in substituting or augmenting force feedback. Such substitution or augmentation could be used when force feedback is unattainable or attenuated due to device limitations or system instability.

Nitric oxide transport in normal human thoracic aorta: effects of hemodynamics and nitric oxide scavengers.

Despite the crucial role of nitric oxide (NO) in the homeostasis of the vasculature, little quantitative information exists concerning NO transport and distribution in medium and large-sized arteries where atherosclerosis and aneurysm occur and hemodynamics is complex. We hypothesized that local hemodynamics in arteries may govern NO transport and affect the distribution of NO in the arteries, hence playing an important role in the localization of vascular diseases. To substantiate this hypothesis, we presented a lumen/wall model of the human aorta based on its MRI images to simulate the production, transport and consumption of NO in the arterial lumen and within the aortic wall. The results demonstrated that the distribution of NO in the aorta was quite uneven with remarkably reduced NO bioavailability in regions of disturbed flow, and local hemodynamics could affect NO distribution mainly via flow dependent NO production rate of endothelium. In addition, erythrocytes in the blood could moderately modulate NO concentration in the aorta, especially at the endothelial surface. However, the reaction of NO within the wall could only slightly affect NO concentration on the luminal surface, but strongly reduce NO concentration within the aortic wall. A strong positive correlation was revealed between wall shear stress and NO concentration, which was affected by local hemodynamics and NO reaction rate. In conclusion, the distribution of NO in the aorta may be determined by local hemodynamics and modulated differently by NO scavengers in the lumen and within the wall.

Hemodynamic study of overlapping bare-metal stents intervention to aortic aneurysm.

To investigate the hemodynamic performance of overlapping bare-metal stents intervention treatment to thoracic aortic aneurysms (TAA), three simplified TAA models, representing, no stent, with a single stent and 2 overlapped stents deployed in the aneurismal sac, were studied and compared in terms of flow velocity, wall shear stress (WSS) and pressure distributions by means of computational fluid dynamics. The results showed that overlapping stents intervention induced a flow field of slow velocity near the aneurismal wall. Single stent deployment in the sac reduced the jet-like flow formed prior to the proximal neck of the aneurysm, which impinged on the internal wall of the aneurysm. This jet-like flow vanished completely in the overlapping double stents case. Overlapping stents intervention led to an evident decrease in WSS; meanwhile, the pressure acting on the wall of the aneurysm was reduced slightly and presented more uniform distribution. The results therefore indicated that overlapping stents intervention may effectively isolate the thoracic aortic aneurysm, protecting it from rupture. In conclusion, overlapping bare-metal stents may serve a purpose similar to that of the multilayer aneurysm repair system (MARS) manufactured by Cardiatis SA (Isnes, Belgium).

Smart photothermal-triggered bilayer phase transition in AuNPs-liposomes to release drug.

Novel thermosensitive liposomes with embedded Au nanoparticles (AuNPs) in the liposome bilayer were prepared by a combination method of film build and supercritical CO(2) incubation. These AuNPs-liposomes possess AuNPs that are embedded in the bilayer and a drug that is encapsulated in the central aqueous compartment. The AuNPs in the liposomes can strongly absorb light energy and efficiently convert the absorbed energy to heat. The localized heat induces a phase transition in the liposome bilayer and releases the drug. The drug release from the AuNPs-liposomes can be controlled by the irradiation time and AuNPs concentration in the AuNPs-liposomes at room temperature, where the AuNPs function as a nanoswitch for triggering drug release both spatially and temporally. The results suggest that drug release from the AuNPs-liposomes is due to a photothermic effect that induces phase transition of the liposomes rather than destruction of the liposome bilayer.

An Optical Actuation System and Curvature Sensor for a MR-compatible Active Needle.

A side optical actuation method is presented for a slender MR-compatible active needle. The needle includes an active region with a shape memory alloy (SMA) wire actuator, where the wire generates a contraction force when optically heated by a laser delivered though optical fibers, producing needle tip bending. A prototype, with multiple side heating spots, demonstrates twice as fast an initial response compared to fiber tip heating when 0.8 W of optical power is applied. A single-ended optical sensor with a gold reflector is also presented to measure the curvature as a function of optical transmission loss. Preliminary tests with the sensor prototype demonstrate approximately linear response and a repeatable signal, independent of the bending history.

A novel way to reduce thrombus build-up in vena cava filters.

OBJECTIVES AND BACKGROUND: The build-up of thromboses in vena cava filters after deployment presents serious problem to the patients. We proposed a novel way to overcome this problem in a belief that intentionally induced swirling flow can optimize blood flow patterns in vena cava filters, enhance the stirring motion of flow, in turn accelerate the dissolution of blood clots captured in the filter and facilitate blood to flow pass through the filters. METHODS: In this study, we experimentally compared the work efficiency of a vena cava filter under swirling flow condition with that of the same filter under normal flow condition. RESULTS: The results show that when compared to the normal flow, the swirling flow indeed has a significantly beneficial effect on a VCF which can decrease its flow-out time nearly 40% and reduce clot build-up in the filter more than 50%. CONCLUSIONS: We therefore believe that the design of an ideal VCF should take how to create swirling flow in the filter into the consideration.

Effect of non-Newtonian and pulsatile blood flow on mass transport in the human aorta.

To investigate the effects of both non-Newtonian behavior and the pulsation of blood flow on the distributions of luminal surface LDL concentration and oxygen flux along the wall of the human aorta, we numerically compared a non-Newtonian model with the Newtonian one under both steady flow and in vivo pulsatile flow conditions using a human aorta model constructed from MRI images. The results showed that under steady flow conditions, although the shear thinning non-Newtonian nature of blood could elevate wall shear stress (WSS) in most regions of the aorta, especially areas with low WSS, it had little effect on luminal surface LDL concentration (c(w)) in most regions of the aorta. Nevertheless, it could significantly enhance c(w) in areas with high luminal surface LDL concentration through the shear dependent diffusivity of LDLs. For oxygen transport, the shear thinning non-Newtonian nature of blood could slightly reduce oxygen flux in most regions of the aorta, but this effect became much more apparent in areas with already low oxygen flux. The pulsation of blood flow could significantly reduce c(w) and enhance oxygen flux in these disturbed places. In most other regions of the aorta, the oxygen flux was also significantly higher than that for the steady flow simulation. In conclusion, the shear shining non-Newtonian nature of blood has little effect on LDL and oxygen transport in most regions of the aorta, but in the atherogenic-prone areas where luminal surface LDL concentration is high and oxygen flux is low, its effect is apparent. Similar is for the effect of pulsatile flow on the transport of LDLs. But, the pulsation of blood flow can apparently affect oxygen flux in the aorta, especially in areas with low oxygen flux.

Establishment of a novel model for studying the effects of extracts of Chinese herb medicine on human type II 5alpha-reductase in vitro.

Human steroid 5alpha-reductase type II (hSRD5A2) and dihydrotestosterone (DHT) play important roles in benign prostatic hyperplasia (BPH). The aim of our study was to establish a novel model to investigate the inhibitory effects of extracts and compounds of Chinese herb medicine on hSRD5A2. The gene, hSRD5A2, was artificially synthesized and cloned into pcDNA3.1(+) vector, which was transfected into CHO cells by liposome. Transfected cells were screened through G418 and MTX. The expressed protein of hSRD5A2 by cells was purified and detected by western blotting. A minimum reactive system comprising hSRD5A2 and testosterone (T) as substrate together with NADPH as hydrogen donor was established for screening inhibitors of hSRD5A2. The reaction system was optimized in the concentrations of T, NADPH, and hSRD5A2 and reaction temperature, time, and activity of hSRD5A2 were determined by the production of DHT. Furthermore, we screened some extracts and compounds of Chinese herb medicine using this model. The concentrations of T, NADPH, and hSRD5A2 were 0.02 microM, 0.8 mM, and 0.05 U/microl, respectively, in the model; maximum activity of hSRD5A2 was achieved at 37 degrees C and 60 min reaction, and mangiferin had significant inhibitory effect on the activity of hSRD5A2. The model in this study is convenient and reliable for screening and evaluation of inhibitors of hSRD5A2; mangiferin may be a potential medicine for the treatment of BPH.

Effect of swirling flow on the uptakes of native and oxidized LDLs in a straight segment of the rabbit thoracic aorta.

To elucidate the physiological significance of the spiral flow in the arterial system from the viewpoint of atherogenic lipid transport, an ex vivo experimental comparative study was designed to investigate the effect of swirling flow on the distribution of native 3,3'-dioctadecylindocarbocyanine-low-density lipoproteins (DiI-LDL) and DiI-ox-LDL uptakes by segments of the rabbit thoracic aorta. The experimental results showed that when compared with the normal flow, the swirling flow generated in the test arteries significantly reduced the DiI-LDL and DiI-ox-LDL uptakes by the arterial walls. The results also showed that the values of DiI-ox-LDL uptake were higher than those of DiI-LDL uptake at the same sample position in both the normal flow group and the swirling flow group. Most interestingly, the experimental results found that the percentage increase in DiI-ox-LDL uptake was much larger than that in DiI-LDL uptake when the perfusion duration increased from 3 to 24 h. In conclusion, the present study substantiated the hypothesis that the spiral flow in the arterial system plays a beneficial role in protecting the arterial wall from atherogenesis. Meanwhile, it supported the concept that the receptor-mediated bindings of LDL uptake, the barrier function of the arterial endothelial linings and the mass transport phenomenon of LDL concentration polarization are all involved in the infiltration/accumulation of atherogenic lipids within the arterial wall.