Resveratrol mediates mitochondrial function through the sirtuin 3 pathway to improve abnormal metabolic remodeling in atrial fibrillation.

This study investigated the impact of resveratrol on abnormal metabolic remodeling in atrial fibrillation (AF) and explored potential molecular mechanisms. An AF cell model was established by high-frequency electrical stimulation of HL-1 atrial muscle cells. Resveratrol concentrations were optimized using CCK-8 and flow cytometry. AF-induced increases in ROS and mitochondrial calcium, along with decreased adenosine triphosphate (ATP) and mitochondrial membrane potential, were observed. Resveratrol mitigated these changes and maintained normal mitochondrial morphology. Moreover, resveratrol acted through the SIRT3-dependent pathway, as evidenced by its ability to suppress AF-induced acetylation of key metabolic enzymes. SIRT3 overexpression controls acetylation modifications, suggesting its regulatory role. In conclusion, resveratrol's SIRT3-dependent pathway intervenes in AF-induced mitochondrial dysfunction, presenting a potential therapeutic avenue for AF-related metabolic disorders. This study sheds light on the role of resveratrol in mitigating AF-induced mitochondrial remodeling and highlights its potential as a novel treatment for AF.

Migration and adsorption of naphthalene in road-deposited sediments from stormwater runoff: Impact of the particle size.

In this study, we explored the impact of RDS particle size on the migration dynamics of RDS and naphthalene through rigorous wash-off experiments. The results illuminated that smaller RDS particles showed higher mobility in stormwater runoff. On the other hand, RDS particles larger than 150 µm showed migration ratios below 2 %, suggesting that naphthalene adsorbed on larger RDS primarily migrated in dissolved form. Furthermore, we investigated the migration behaviors of RDS and naphthalene under varied conditions, including rainfall intensity, duration, and naphthalene concentrations. Larger rainfall intensity promoted the naphthalene release from RDS, while long rainfall duration (≥10 min) impeded the migration velocities (≤2.91 %/5 min for RDS, and ≤3.32 %/5 min for corresponding naphthalene) of RDS and naphthalene. Additionally, higher naphthalene concentrations in RDS diminished migration ratios of dissolved naphthalene. Significantly, the maximum uptake of naphthalene on RDS was 6.02 mg/g by the adsorption Langmuir isotherm. Importantly, the adsorption process of naphthalene in RDS is primarily governed by the physical adsorption, as demonstrated by the successive desorption experiments, which showed the desorption rate of up to 87.32 %. Moreover, advanced characterizations such as XPS, FTIR and Raman spectra further confirmed the physical nature of the adsorption process. These findings may help the understanding of the migration behavior of other pollutants in urban surface particulates.

Effects of radiofrequency balloon angioplasty on the abdominal aorta in atherosclerotic rabbits.

OBJECTIVES: A novel temperature-controlled intravascular radiofrequency balloon angioplasty (RFBA) technique was designed and developed for atherosclerosis (AS) management. METHODS: After establishing an AS model based on a balloon denudation injury of the abdominal aorta and a high cholesterol diet in rabbits, 46 animals were randomly assigned to the RFBA group (n = 28) or the plain balloon angioplasty (PBA) group (n = 28). The groups were further subdivided based on post-treatment euthanasia times (1 hour, 7 days, 14 days, and 28 days). Histopathological changes were observed by hematoxylin and eosin and Masson's staining. Immunohistochemistry, western blotting, and real-time quantitative polymerase chain reaction were used to detect changes in pro-inflammatory, anti-inflammatory, and apoptotic factors; TGF-ß/Smad-2 pathway protein Immune levels; and mRNA levels in tissues, respectively. RESULTS: The vascular lumen area in the RFBA group was larger than that in the PBA group at the same time points, although the change in the vascular lumen area was not different between groups. The expression of Bax, TGF-ß, Smad-2, and Caspase-3 in the RFBA group was significantly higher than that in the PBA group. The expression levels of Bcl-2 in the RFBA group were significantly lower than those in the PBA group. CONCLUSIONS: At 28 days, RFBA dilated the atherosclerotic blood vessels and thickened the fibrous cap of atherosclerotic plaques to promote plaque stability. RFBA was also found to activate apoptotic factors and the TGF-/Smad-2 inflammatory pathway.

Mechanisms of Intravascular Linear Ablation Induced Restenosis in Rabbit Abdominal Aorta.

OBJECTIVES: Percutaneous coronary intervention (PCI) is the mainstay treatment for coronary artery disease but complications such as in-stent restenosis and thrombosis remain problematic. Radiofrequency balloon angioplasty (RBA) can improve lumen dimension, fusing intimal tears, and artery dissection but is associated with higher restenosis rate. METHODS: After establishing an atherosclerosis model based on endothelial abrasion and high cholesterol diet, forty-five rabbits were randomly divided into three groups: RBA (n=20), percutaneous transluminal angioplasty (PTA) (n=20), and control groups (n=5). The RBA and PTA groups were subdivided according to harvested time posttreatment, respectively (1 hour, 7 days, 14 days, and 28 days). Aorta segments were then isolated for hematoxylin and eosin staining, Masson trichrome staining, immunohistochemistry, and Western blot for TLR-4, NF-κB, MCP-1, and VCAM-1expression. RESULTS: At 28 days, intimal area was significantly lower in the RBA group compared to the PTA and control groups, whilst luminal and medial area were comparable in the RBA and PTA group but higher and lower than the control group, respectively. Expression of TLR-4, NF-κB, MCP-1, and VCAM-1 showed no significant difference between RBA and PTA groups. CONCLUSIONS: RBA can depress the intimal hyperplasia and promote dilatation of the artery to greater extents than PTA at 28 days. However, this did not involve TLR-4 signaling pathway, which likely plays a negligible role in mediating restenosis. Reduction of intimal hyperplasia may be due to injury of ablation to the tunica media and inhibition of VSMC proliferation and migration.

Fast nonlinear image reconstruction for scanning impedance imaging.

Scanning (electrical) impedance imaging (SII) is a novel high-resolution imaging modality that has the potential of imaging the electrical properties of thin biological tissues. In this paper, we apply the reciprocity principle to the modeling of the SII system and develop a fast nonlinear inverse method for image reconstruction. The method is fast because it uses convolution to eliminate the requirement of a numerical solver for the 3-D electrostatic field in the SII system. Numerical results show that our approach can accurately reveal the exact conductivity distribution from the measured current map for different 2-D simulation phantoms. Experiments were also performed using our SII system for a piece of butterfly wing and breast cancer cells. Two-dimensional current images were measured and corresponding quantitative conductivity images were restored using our approach. The reconstructed images are quantitative and reveal details not present in the measured images.

Degradation of porous poly(D,L-lactic-co-glycolic acid) films based on water diffusion.

Poly(D,L-lactic-co-glycolic acid) has been extensively used as a controlled release carrier for drug delivery due to its good biocompatibility, biodegradability, and mechanical strength. Effects of dense and porous film's degradation behavior have been systematically investigated up to 17 weeks in Hank's Simulated Body Fluid at 37 degrees C. The degradation of the films was studied by measuring changes in weight, molecular weight and its distribution, morphology, composition etc.. A special thing was that the differences in water diffusion in dense and porous structure films caused the different degradation behavior. According to the characteristic changes of various properties of films, the degradation process is suggested to be roughly divided into four stages, tentatively named as water absorption stage, dramatic loss of molecular weight or micro-pores formed stage, loss of weight or enlarged-pores formed stage, pores diminished or pores collapse stage.

Simple linear models of scanning impedance imaging for fast reconstruction of relative conductivity of biological samples.

Scanning impedance imaging (SH) uses a noncontacting electrical probe held at a known voltage and scanned over a thin sample on a ground plane in a conductive medium to obtain images of current. The current image is related in a nonlinear way to the conductivity of the sample. This paper develops the theory behind SII showing how the measured current relates to the desired conductivity. Also included is the development of a simplified, linear model that is effective in explaining many of the experimental results. Good agreement of the linear model with step-response data over an insulator is shown. The linear model shows that the current is a blurred version of the conductivity. Simple deblurring methods can, therefore, be applied to obtain relative conductivity images from the raw current data. Raw SII data from a flower-petal and a leaf sample are shown as well as relative conductivity images deblurred using the linear model.

A fast linear reconstruction method for scanning impedance imaging.

Scanning electrical impedance imaging (SII) has been developed and implemented as a novel high resolution imaging modality with the potential of imaging the electrical properties of biological tissues. In this paper, a fast linear model is derived and applied to the impedance image reconstruction of scanning impedance imaging. With the help of both the deblurring concept and the reciprocity principle, this new approach leads to a calibrated approximation of the exact impedance distribution rather than a relative one from the original simplified linear method. Additionally, the method shows much less computational cost than the more straightforward nonlinear inverse method based on the forward model. The kernel function of this new approach is described and compared to the kernel of the simplified linear method. Two-dimensional impedance images of a flower petal and cancer cells are reconstructed using this method. The images reveal details not present in the measured images.

Modelling for scanning impedance imaging.

Scanning electrical impedance imaging (SII) is a previously-introduced high resolution imaging modality with the potential of imaging the electrical activities of biological tissues. In this paper, a detailed complex electrostatic model is derived to describe the physical phenomena of the SII system. This model reveals the relationship between the voltage measurement and impedance distribution and also shows how system parameters such as height affect the resolution of the impedance image. A numerical solution is developed for this model based on the finite difference method (FDM). A variation of classical FDM is used to solve the complicated boundary conditions introduced by the combination of the electrostatic field and the peripheral circuit. Good correspondence can be observed when comparing the model simulation with experimental data acquired during a line-scan. It can be seen that the model provides a good explanation for the experimental results and can assist in the design of the special dual-conductor impedance probe used in the SII system. A two-source improvement for the SII system which is motivated by the modelling work is implemented and the corresponding physical analysis is obtained. It can help the reduction of the current contribution from the shield to the tip so that higher resolution can be achieved.

Noncontact scanning electrical impedance imaging.

We are interested in applying electrical impedance imaging to a single cell because it has potential to reveal both cell anatomy and cell function. Unfortunately, classic impedance imaging techniques are not applicable to this small scale measurement due to their low resolution. In this paper, a different method of impedance imaging is developed based on a noncontact scanning system. In this system, the imaging sample is immersed in an aqueous solution allowing for the use of various probe designs. Among those designs, we discuss a novel shield-probe design that has the advantage of better signal-to-noise ratio with higher resolution compared to other probes. Images showing the magnitude of current for each scanned point were obtained using this configuration. A low-frequency linear physical model helps to relate the current to the conductivity at each point. Line-scan data of high impedance contrast structures can be shown to be a good fit to this model. The first two-dimensional impedance image of biological tissues generated by this technique is shown with resolution on the order of 100 mum. The image reveals details not present in the optical image.

Non-contact scanning electrical impedance imaging.

We are interested in applying electrical impedance imaging to a single cell because it has potential to reveal both cell anatomy and cell function. Unfortunately, classic impedance imaging techniques are not applicable to this small scale measurement due to their low resolution. In this paper, a different method of impedance imaging is developed based on a non-contact scanning system. In this system, the imaging sample is immersed in an aqueous solution allowing for the use of various probe designs. Among those designs, we discuss a novel shield-probe design that has the advantage of better signal-to-noise ratio with higher resolution compared to other probes. Images showing the magnitude of current for each scanned point were obtained using this configuration. A low-frequency linear physical model helps to relate the current to the conductivity at each point. Line-scan data of high impedance contrast structures can be shown to be a good fit to this model. The first two-dimensional impedance image of biological tissues generated by this technique is shown with resolution on the order of 100 mum. The image reveals details not present in the optical image.