Effect of the Combination of Probiotics and Korean Red Ginseng on Diabetic Wound Healing Exposed to Diesel Exhaust Particles(DEPs).

Background and Objectives: Diesel exhaust particles (DEPs) are a major component of air pollution and adversely affect respiratory and cardiovascular disease and diabetic foot ulcers if diabetic patients are exposed to them. There are currently no studies on treating diabetic wounds exposed to DEPs. So, the effect of a combination of probiotics and Korean red ginseng on a diabetic wound model exposed to DEPs was confirmed. Materials and Methods: Rats were randomly divided into three groups according to DEP inhalation concentration and whether they underwent applications of probiotics (PB) and Korean red ginseng (KRG). Wound tissue was collected from all rats, and wound healing was evaluated using molecular biology and histology methods. Results: The wound size of all groups decreased over time, but there was no significant difference. As a result of the molecular biology experiment, the expression of NF-κB p65 on day 7 was significantly higher in group 2 than in the normal control group. As a result of histological analysis, unlike the primary control group, it was confirmed that granule tissue was formed on the 14th day in the normal control group and group 2. Conclusions: The findings in this study suggest that combined treatment with PB and KRG can promote the healing of DEP-exposed diabetic wounds.

Efficacy of Silver Nanoparticles-Loaded Bone Cement against an MRSA Induced-Osteomyelitis in a Rat Model.

Background and Objectives: The purpose of this study was to assess the cytotoxicity and antibacterial effects of AgNP-impregnated Tetracalcium phosphate-dicalcium phosphate dihydrate (TTCP-DCPD). Materials and Methods: Using in vitro experiments, the cytotoxicity of AgNP-impregnated TTCP-DCPD against fibroblasts and osteocytes was assessed in terms of cell viability by water-soluble tetrazolium salt assay. To assess antibacterial effects, a disc diffusion test was used; osteomyelitis was induced first in vivo, by injection of methicillin-resistant Staphylococcus aureus into the tibia of rats. AgNP-impregnated TTCP-DCPD bone cement was then applied at various silver concentrations for 3 or 12 weeks. Antibacterial effects were assessed by culturing and reverse transcription-polymerase chain reaction (RT-PCR). For histological observation, the bone tissues were stained using hematoxylin and eosin. Results: Cell viability was decreased by the impregnated bone cement but did not differ according to AgNP concentration. The diameter of the growth-inhibited zone of MRSA was between 4.1 and 13.3 mm on the disks treated with AgNP, indicating antimicrobial effects. In vivo, the numbers of bacterial colonies were reduced in the 12-week treatment groups compared to the 3-week treatment groups. The groups treated with a higher (10×) dose of AgNP (G2-G5) showed a tendency of lower bacterial colony counts compared to the group without AgNP (G1). The PCR analysis results showed a tendency of decreased bacterial gene expression in the AgNP-impregnated TTCP-DCPD groups (G2-G5) compared to the group without AgNP (G1) at 3 and 12 weeks. In the H&E staining, the degree of inflammation and necrosis of the AgNP-impregnated TTCP-DCPD groups (G2-G5) showed a tendency to be lower at 3 and 12 weeks compared to the control group. Our results suggest that AgNP-impregnated TTCP-DCPD cement has antimicrobial effects. Conclusions: This study indicates that AgNP-impregnated TTCP-DCPD bone cement could be considered to treat osteomyelitis.

Offset of apparent hyperpolarized 13 C lactate flux by the use of adjuvant metformin in ionizing radiation therapy in vivo.

An increase in hyperpolarized (HP) [1-13 C]lactate production has been suggested as a biomarker for cancer occurrence as well as for response monitoring of cancer treatment. Recently, the use of metformin has been suggested as an anticancer or adjuvant treatment. By regulating the cytosolic NAD+ /NADH redox state, metformin stimulates lactate production and increases the HP [1-13 C]lactate conversion rate in the kidney, liver, and heart. In general, increased HP [1-13 C]lactate is regarded as a sign of cancer occurrence or tumor growth. Thus, the relationship between the tumor suppression effect of metformin and the change in metabolism monitored by HP [1-13 C]pyruvate MRS in cancer treatment needs to be investigated. The present study was performed using a brain metastasis animal model with MDA-MB-231(BR)-Luc breast cancer cells. HP [1-13 C]pyruvate MRS, T2 -weighted MRI, and bioluminescence imaging were performed in groups treated with metformin or adjuvant metformin and radiation therapy. Metformin treatment alone did not display a tumor suppression effect, and the HP [1-13 C]lactate conversion rate increased. In radiation therapy, the HP [1-13 C]lactate conversion rate decreased with tumor suppression, with a p-value of 0.028. In the adjuvant metformin and radiation treatment, the tumor suppression effect increased, with a p-value of 0.001. However, the apparent HP [1-13 C]lactate conversion rate (Kpl ) was observed to be offset by two opposite effects: a decrease on radiation therapy and an increase caused by metformin treatment. Although HP [1-13 C]pyruvate MRS could not evaluate the tumor suppression effect of adjuvant metformin and radiation therapy due to the offset phenomenon, metabolic changes following only metformin pre-treatment could be monitored. Therefore, our results indicate that the interpretation of HP [1-13 C]pyruvate MRS for response monitoring of cancer treatment should be carried out with caution when metformin is used as an adjuvant cancer therapy.

Dynamic hyperpolarized 13 C MR spectroscopic imaging using SPICE in mouse kidney at 9.4 T.

This study aims to investigate the feasibility of dynamic hyperpolarized 13 C MR spectroscopic imaging (MRSI) using the SPectroscopic Imaging by exploiting spatiospectral CorrElation (SPICE) technique and an estimation of the spatially resolved conversion constant rate (kpl ). An acquisition scheme comprising a single training dataset and several imaging datasets was proposed considering hyperpolarized 13 C circumstances. The feasibility and advantage of the scheme were investigated in two parts: (a) consistency of spectral basis over time and (b) accuracy of the estimated kpl . The simulations and in vivo experiments support accurate kpl estimation with consistent spectral bases. The proposed method was implemented in an enzyme phantom and via in vivo experiments. In the enzyme phantom experiments, spatially resolved homogeneous kpl maps were observed. In the in vivo experiments, normal diet (ND) mice and high-fat diet (HFD) mice had kpl (s-1 ) values of medullar (ND: 0.0119 ± 0.0022, HFD: 0.0195 ± 0.0005) and cortical (ND: 0.0148 ±0.0023, HFD: 0.0224 ±0.0054) regions which were higher than vascular (ND: 0.0087 ±0.0013, HFD: 0.0132 ±0.0050) regions. In particular, the kpl value in the medullar region exhibited a significant difference between the two diet groups. In summary, the feasibility of using modified SPICE for dynamic hyperpolarized 13 C MRSI was demonstrated via simulations and in vivo experiments. The consistency of spectral bases over time and the accuracy of the estimated kpl values validate the proposed acquisition scheme, which comprises only a single training dataset. The proposed method improved the spatial resolution of dynamic hyperpolarized 13 C MRSI, which could be used for kpl estimation using high signal-to-noise ratio spectral bases.

High resolution hyperpolarized 13 C MRSI using SPICE at 9.4T.

PURPOSE: To test the feasibility of using the SPICE (SPectroscopic Imaging by exploiting spatiospectral CorrElation) technique, which uses the partial separability of spectroscopic data, for high resolution hyperpolarized (HP) 13 C spectroscopic imaging. METHODS: Numerical simulations were performed to investigate the impact of transient HP signals on SPICE reconstruction. Furthermore, spectroscopic imaging exams from SPICE and conventional EPSI (echo-planar spectroscopic imaging) were simulated for comparison. For in vivo experiments, HP 13 C SPICE was performed in a mouse kidney by means of the injection of HP [1-13 C] pyruvate at 9.4T. RESULTS: The variation of lactate/pyruvate from the simulated SPICE was less than 4% under various factors that affect the transient HP signal, suggesting that the impact is negligible. We found that while HP 13 C EPSI was limited to the low signal-to-noise ratio (SNR) of lactate, these limitations were mitigated through HP 13 C SPICE, facilitating the improved SNR of lactate and the distinction of tissues. Acquisition of a high resolution HP 13 C spectroscopic image was possible for the in vivo experiments. With the fine structural information, the acquired image showed higher signal of pyruvate and lactate in the renal cortices than in the medullas, which is known to be attributed to higher activity of lactate dehydrogenase. CONCLUSION: The feasibility of HP 13 C SPICE was investigated. Simulation studies were conducted and in vivo experiments were performed in the mouse kidney at 9.4T. Results confirmed that a high resolution HP 13 C spectroscopic image with adequate spectral resolution can be obtained. Magn Reson Med 80:703-710, 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Flow-suppressed hyperpolarized 13 C chemical shift imaging using velocity-optimized bipolar gradient in mouse liver tumors at 9.4 T.

PURPOSE: To optimize and investigate the influence of bipolar gradients for flow suppression in metabolic quantification of hyperpolarized 13 C chemical shift imaging (CSI) of mouse liver at 9.4 T. METHODS: The trade-off between the amount of flow suppression using bipolar gradients and T2* effect from static spins was simulated. A free induction decay CSI sequence with alternations between the flow-suppressed and non-flow-suppressed acquisitions for each repetition time was developed and was applied to liver tumor-bearing mice via injection of hyperpolarized [1-13 C] pyruvate. RESULTS: The in vivo results from flow suppression using the velocity-optimized bipolar gradient were comparable with the simulation results. The vascular signal was adequately suppressed and signal loss in stationary tissue was minimized. Application of the velocity-optimized bipolar gradient to tumor-bearing mice showed reduction in the vessel-derived pyruvate signal contamination, and the average lactate/pyruvate ratio increased by 0.095 (P < 0.05) in the tumor region after flow suppression. CONCLUSION: Optimization of the bipolar gradient is essential because of the short 13 C T2* and high signal in venous flow in the mouse liver. The proposed velocity-optimized bipolar gradient can suppress the vascular signal, minimizing T2*-related signal loss in stationary tissues at 9.4 T. Magn Reson Med 78:1674-1682, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

An indirect method for in vivo T2 mapping of [1-13 C] pyruvate using hyperpolarized 13 C CSI.

An indirect method for in vivo T2 mapping of 13 C-labeled metabolites using T2 and T2 * information of water protons obtained a priori is proposed. The T2 values of 13 C metabolites are inferred using the relationship to T2 ' of coexisting 1 H and the T2 * of 13 C metabolites, which is measured using routine hyperpolarized 13 C CSI data. The concept is verified with phantom studies. Simulations were performed to evaluate the extent of T2 estimation accuracy due to errors in the other measurements. Also, bias in the 13 C T2 * estimation from the 13 C CSI data was studied. In vivo experiments were performed from the brains of normal rats and a rat with C6 glioma. Simulation results indicate that the proposed method provides accurate and unbiased 13 C T2 values within typical experimental settings. The in vivo studies found that the estimated T2 of [1-13 C] pyruvate using the indirect method was longer in tumor than in normal tissues and gave values similar to previous reports. This method can estimate localized T2 relaxation times from multiple voxels using conventional hyperpolarized 13 C CSI and can potentially be used with time resolved fast CSI.

Toward Accumulation of Magnetic Nanoparticles into Tissues of Small Porosity.

Magnetic concentration of drug-laden magnetic nanoparticles has been proven to increase the delivery efficiency of treatment by 2-fold. In these techniques, particles are concentrated by the presence of a magnetic source that delivers a very high magnetic field and a strong magnetic field gradient. We have found that such magnetic conditions cause even 150 nm particles to aggregate significantly into assemblies that exceed several micrometers in length within minutes. Such assembly sizes exceed the effective intercellular pore size of tumor tissues preventing these drug-laden magnetic nanoparticles from reaching their target sites. We demonstrate that by using dynamic magnetic fields instead, we can break up these magnetic nanoparticles while simultaneously concentrating them at target sites. The dynamic fields we investigate involve precessing the field direction while maintaining a field gradient. Manipulating the field direction drives the particles into attractive and repulsive configurations that can be tuned to assemble or disassemble these particle clusters. Here, we develop a simple analytic model to describe the kinetic thresholds of disassembly and we compare both experimental and numerical results of magnetic particle suspensions subjected to dynamic fields. Finally we apply these methods to demonstrate penetration in a porous scaffold with a similar pore size to that expected of a tumor tissue.

Effects of Iron-Oxide Nanoparticle Surface Chemistry on Uptake Kinetics and Cytotoxicity in CHO-K1 Cells.

Superparamagnetic iron-oxide nanoparticles (SPIONs) show great promise for multiple applications in biomedicine. While a number of studies have examined their safety profile, the toxicity of these particles on reproductive organs remains uncertain. The goal of this study was to evaluate the cytotoxicity of starch-coated, aminated, and PEGylated SPIONs on a cell line derived from Chinese Hamster ovaries (CHO-K1 cells). We evaluated the effect of particle diameter (50 and 100 nm) and polyethylene glycol (PEG) chain length (2k, 5k and 20k Da) on the cytotoxicity of SPIONs by investigating cell viability using the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and sulforhodamine B (SRB) assays. The kinetics and extent of SPION uptake by CHO-K1 cells was also studied, as well as the resulting generation of intracellular reactive oxygen species (ROS). Cell toxicity profiles of SPIONs correlated strongly with their cellular uptake kinetics, which was strongly dependent on surface properties of the particles. PEGylation caused a decrease in both uptake and cytotoxicity compared to aminated SPIONs. Interestingly, 2k Da PEG-modifed SPIONs displayed the lowest cellular uptake and cytotoxicity among all studied particles. These results emphasize the importance of surface coatings when engineering nanoparticles for biomedical applications.

Exploiting Size-Dependent Drag and Magnetic Forces for Size-Specific Separation of Magnetic Nanoparticles.

Realizing the full potential of magnetic nanoparticles (MNPs) in nanomedicine requires the optimization of their physical and chemical properties. Elucidation of the effects of these properties on clinical diagnostic or therapeutic properties, however, requires the synthesis or purification of homogenous samples, which has proved to be difficult. While initial simulations indicated that size-selective separation could be achieved by flowing magnetic nanoparticles through a magnetic field, subsequent in vitro experiments were unable to reproduce the predicted results. Magnetic field-flow fractionation, however, was found to be an effective method for the separation of polydisperse suspensions of iron oxide nanoparticles with diameters greater than 20 nm. While similar methods have been used to separate magnetic nanoparticles before, no previous work has been done with magnetic nanoparticles between 20 and 200 nm. Both transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis were used to confirm the size of the MNPs. Further development of this work could lead to MNPs with the narrow size distributions necessary for their in vitro and in vivo optimization.

Elevation of S100 calcium binding protein A9 in sputum of neutrophilic inflammation in severe uncontrolled asthma.

BACKGROUND: Neutrophilic airway inflammation is frequently observed in severe uncontrolled asthma (UA) and controlled asthma (CA). However, there is no sputum biomarker to differentiate the 2 conditions. OBJECTIVE: To identify biomarkers of severe uncontrolled asthma with neutrophilic airway inflammation. METHODS: Sputum with a neutrophil content larger than 70% was pooled from 5 patients with severe UA and from 10 patients with CA. Two-dimensional electrophoresis was adopted for differential display proteomics, and candidate proteins were identified using matrix-assisted laser adsorption/ionization-time of flight mass spectrometric analysis. S100 calcium binding protein A9 (S100A9) was identified by western blot and its level was measured in sputum from asthmatics with varying disease severity, patients with chronic obstructive lung disease, and normal controls using enzyme-linked immunosorbent assay. RESULTS: Fourteen protein spots exhibited differences in relative intensity between patients with severe UA and those with CA. Matrix-assisted laser adsorption/ionization-time of flight/time of flight of these spots showed an increase in human neutrophil peptide-2, S100A9, ß-amylase, neutrophil gelatinase-associated lipocalin, 4-aminobutyrate transaminase, and cystatin SA in patients with UA compared with patients with CA. There was a decrease in the plunc precursor, complement C3 component, immunoglobulin heavy-chain variable region, glial fibrillary acidic protein isoform-1, IgM κIIIb SON, MLL-AF4 der(11) fusion protein, cytokeratin-8, and recombinant IgG4 heavy chain. S100A9 was detected at a higher level in western blots of neutrophilic sputum from patients with severe UA vs CA. S100A9 levels were significantly increased, as measured by enzyme-linked immunosorbent assay, in neutrophilic UA compared with CA, eosinophilic UA and CA, and chronic obstructive lung disease. CONCLUSION: S100A9 in sputum may be a biomarker of neutrophilic inflammation in severe UA.

Hyperpolarized [1-13C]pyruvate Magnetic Resonance Spectroscopy Shows That Agmatine Increased Lactate Production in the Brain of Type 2 Diabetic Mice.

PURPOSE: Type 2 diabetes mellitus (T2DM) is associated with a 2-fold increased risk of developing Alzheimer's disease. In earlier research, agmatine has been demonstrated to alleviate diabetes symptoms and increase cognitive performance. However, it is unclear whether the improvement of cognitive function is attributable to the reduction of diabetic symptoms or its direct influence on brain metabolism. Using hyperpolarized (HP) [1-13C]pyruvate magnetic resonance spectroscopy (MRS), this study intends to evaluate the influence of agmatine on brain metabolism. MATERIALS AND METHODS: ICR mice were fed a high-fat diet and injected with streptozotocin to develop a T2DM animal model. During a 2-week period, T2DM mice were treated with normal saline or 100 mg/kg of agmatine, and brain HP [1-13C]pyruvate MRS was performed. The effect of agmatine on lactate generation and NADH/NAD+ redox state was investigated using C6 and neuro-2a (N2a) cells. RESULTS: As a perfusion marker, the total 13C signals in the brain of T2DM mice (p=0.07) and agmatine-treated mice (p<0.05) were reduced. The conversion constant (Kpl) from [1-13C]pyruvate to [1-13C]lactate was not distinguishable in the brains of T2DM mice but was significantly increased in the brains of agmatine-treated T2DM mice. Treating C6 and N2a cells with agmatine increased NADH/NAD+ratio and lactate generation. CONCLUSION: Agmatine influences the NADH/NAD+ redox state in the brains of T2DM mice, which may be connected with enhanced cognitive performance and increased conversion of HP [1-13C]pyruvate to HP [1-13C]lactate.

Cell-penetrating chitosan/doxorubicin/TAT conjugates for efficient cancer therapy.

In this study, a cell-penetrating peptide, the transactivating transcriptional factor (TAT) domain from HIV, was linked to a chitosan/doxorubicin (chitosan/DOX) conjugate to form a chitosan/DOX/TAT hybrid. The synthesized chitosan/DOX/TAT conjugate showed a different intracellular distribution pattern from a conjugate without TAT. Unlike both free DOX and the conjugate without TAT, the chitosan/DOX/TAT conjugate was capable of efficient cell entry. The chitosan/DOX/TAT conjugate was found to be highly cytotoxic, with an IC(50) value of approximately 480 nM, 2 times less than that of chitosan/DOX (980 nM). The chitosan/DOX/TAT provided decreases in tumor volume of 77.4 and 57.5% compared to free DOX and chitosan/DOX, respectively, in tumor-bearing mice. Therefore, this study suggests that TAT-mediated chitosan/DOX conjugate delivery is effective in slowing tumor growth.

Validation of the Osteomyelitis Induced by Methicillin-Resistant Staphylococcus aureus (MRSA) on Rat Model with Calvaria Defect.

BACKGROUND: Osteomyelitis resulting from bacterial strains, such as methicillin-resistant Staphylococcus aureus (MRSA) that are resistant to multiple drugs, brings further clinical challenges. There is currently no model of osteomyelitis induced by MRSA using rats with calvaria defects. So, We induced osteomyelitis in rat models with the calvaria bone defect. METHODS: The rats were randomly divided into six groups according to inoculation dose levels, which ranged from 6 × 100 to 6 × 105 CFU/5 µl. Bone tissues were retrieved from all rats used in the study and assessed using histology, microbiology, and radiobiology 4 weeks after surgery to evaluate the relationship between inoculation dose and infectivity. RESULTS: In Histological results, high levels of inflammatory responses, bone necrosis, and bacteria were observed in treatment groups G3 to G5. In IHC staining, high levels of cox-2 expression were observed in treatment groups G3. Microbiological observations also indicated that significantly higher numbers of CFUs were found in G3 to G5. In radiography results, the bone mineral density in G3 to G5 was significantly higher than in the control group, G1, and G2. Our results indicate that an inoculating dose of 6 × 103 CFU/5 µl is sufficient to induce the development of osteomyelitis in rat models. CONCLUSION: This study suggests that the minimum dose (6 × 103 CFU/5 µl) can induce osteomyelitis in calvaria rat model. This can offer information and ability of more accurately modeling osteomyelitis and simulating the challenge of osteomyelitis treat.

Danshen Extracts Prevents Obesity and Activates Mitochondrial Function in Brown Adipose Tissue.

BACKGROUND: Danshen has been widely used in oriental medicine to improve body function. The purpose of this study is to investigate the effect of water-soluble Danshen extract (DE) on weight loss and on activation proteins involved in mitochondrial biogenesis in brown adipose tissue (BAT) in obese mice. METHODS: BAT was isolated from 7-week-old male Sprague-Dawley rats, and expression of proteins related to mitochondrial biogenesis was confirmed in both brown preadipocytes and mature brown adipocytes treated with DE. For the in vivo study, low-density lipoprotein receptor knock out mice were divided into three groups and treated for 17 weeks with: standard diet; high fat diet (HFD); HFD+DE. Body weight was measured every week, and oral glucose tolerance test was performed after DE treatment in streptozotocin-induced diabetic mice. To observe the changes in markers related to thermogenesis and adipogenesis in the BAT, white adipose tissue (WAT) and liver of experimental animals, tissues were removed and immediately frozen in liquid nitrogen. RESULTS: DE increased the expression of uncoupling protein 1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha in brown preadipocytes, and also promoted the brown adipocyte differentiation and mitochondrial function in the mature brown adipocytes. Reactive oxygen species production in brown preadipocytes was increased depending on the concentration of DE. DE activates thermogenesis in BAT and normalizes increased body weight and adipogenesis in the liver due to HFD. Browning of WAT was increased in WAT of DE treatment group. CONCLUSION: DE protects against obesity and activates mitochondrial function in BAT.

A dual-reporter system for specific tracing of pancreatic ss-cell lines that non-invasively measures viable in vivo islet cells.

Islet transplantation is a potential treatment for type 1 diabetes. Currently, islet graft survival is measured using invasive methods to determine blood glucose, insulin, and C-peptide levels, even though these variables have limited value. To trace beta-cell survival and functional status, we constructed an adenovirus/adenoassociate virus hybrid vector (Hyb-DR) carrying two reporter genes, luciferase and green fluorescent protein (GFP), linked by the internal ribosome entry site and driven by the rat insulin II promoter. Luciferase activity increased and positive GFP expression was observed in beta-cell lines (MIN6N8 and INS-1E) infected with Hyb-DR. Using an in vivo imaging instrument, the GFP signal was detected in the flanks of nude mice 2 weeks after transplanting Hyb-DR-infected MIN6 cells into the kidney capsule. Coinfection of Hyb-DR with plasmids carrying beta-cell-specific transcription factors also resulted in expression of luciferase and GFP in the non-beta-cell lines (HepG2, FL83B, and YGIC5). Thus, the dual reporter system provided quantitative and visual information about the functionality of the islet mass and activation of the insulin gene.

Efficient labeling of mesenchymal stem cells using cell permeable magnetic nanoparticles.

For the purpose of successfully monitoring labeled cells, optimum labeling efficiency without any side effect is a prerequisite. Magnetic cellular imaging is a new and growing field that allows the visualization of implanted cells in vivo. Herein, superparamagnetic iron oxide (SPIO) nanoparticles were conjugated with a non-toxic protein transduction domain (PTD), identified by the authors and termed low molecular weight protamine (LMWP), to generate efficient and non-toxic cell labeling tools. The cells labeled with LMWP-SPIO presented the highest iron content compared to those labeled with naked SPIO and the complex of SPIO with poly-L-lysine, which is currently used as a transfection agent. In addition to the iron content assay, Prussian staining and confocal observation demonstrated the highest intracellular LMWP-SPIO presence, and the labeling procedure did not alter the cell differentiation capacity of mesenchymal stem cells. Taken together, cell permeable magnetic nanoparticles conjugated with LMWP can be suggested as labeling tools for efficient magnetic imaging of transplanted cells.

Hyperpolarized [1-13C]lactate flux increased in the hippocampal region in diabetic mice.

Increasing evidence suggests there is a relationship between cognitive impairment and metabolic dysfunction. Diabetes is a chronic disease, and metabolic factors affecting brain metabolisms, such as serum glucose, insulin, and glucagon, are altered according to disease progression. In our previous study, we applied hyperpolarized [1-13C] pyruvate magnetic resonance spectroscopy in prediabetic mice after feeding them a 60% high-fat diet (HFD) for 6 months. Ultimately, we detected significantly increased [1-13C]lactate conversion in the whole brain and an almost five-fold increased [1-13C]lactate/pyruvate ratio in the hippocampal region. In the present study, we induced diabetes in mice by injecting streptozotocin and feeding them an HFD for 6 months. Unlike in prediabetic mice, [1-13C]lactate conversion in the diabetic mice did not differ from that in the control group, but [1-13C]lactate/total 13C ratio showed an almost 1.4-fold increase in the hippocampal region. We measured the amount of the lactate and mRNA levels of glucose transporters from isolated hippocampus and cortex samples. In the hippocampus, significantly decreased GLUT1 mRNA levels and increased lactate were detected, suggesting an inconsistency between glucose and pyruvate metabolism. Pyruvate can be produced from oxaloacetate as well as glucose. We investigated ATP citrate lyase (ACLY) because it cleaves citrate into oxaloacetate and acetyl CoA. Phosphorylated ACLY (Ser455), the active form, was increased in both hippocampus and cortex samples of mice injected with streptozotocin and fed an HFD. Also, phosphorylated ACLY/total ACLY showed a positive correlation with lactate amount in the hippocampus. Our results suggest that the brain has different responses to diabetic progression, but, in the hippocampus, maintains metabolic alteration toward increasing lactate production from the prediabetic to the diabetic stage. We suggest that ACLY-mediated pyruvate be used to support lactate levels in the hippocampus in cases of limited glucose availability.

Dielectrophoretic assembly of single gold nanoparticle into nanogap electrodes.

We report the optimization study of assembling single 20 nm gold nano-particle in 20 nm spaced electrode gap via ac dielectrophoresis (DEP) technique. It was observed that time, voltage, and frequency variations influenced significantly the assembly of gold nano-particle in the nano-gap electrodes. Frequency variation study revealed that at lower frequencies (< 1 MHz) the assembling was observed in low field regions; however, at a moderate frequency of 1 MHz, minimum number of nano-particles was assembled in high field region. Trapping of single 20 nm nano-particle in 20 nm spaced electrodes was successfully achieved under the optimized DEP parameters i.e., frequency, applied voltage and time of values corresponding to 1 MHz, 2 V, and 1 sec, respectively, with the yield of almost 66%. Our results show the promise of optimized dielectrophoresis in the future nano-engineering.

Removal and killing of multispecies endodontic biofilms by N-acetylcysteine.

Removal of bacterial biofilm from the root canal system is essential for the management of endodontic disease. Here we evaluated the antibacterial effect of N-acetylcysteine (NAC), a potent antioxidant and mucolytic agent, against mature multispecies endodontic biofilms consisting of Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans and Enterococcus faecalis on sterile human dentin blocks. The biofilms were exposed to NAC (25, 50 and 100mg/mL), saturated calcium hydroxide or 2% chlorhexidine solution for 7 days, then examined by scanning electron microscopy. The biofilm viability was measured by viable cell counts and ATP-bioluminescence assay. NAC showed greater efficacy in biofilm cell removal and killing than the other root canal medicaments. Furthermore, 100mg/mL NAC disrupted the mature multispecies endodontic biofilms completely. These results demonstrate the potential use of NAC in root canal treatment.