Metastasis and immunosuppression promoted by mtDNA and PD-L1 in extracellular vesicles are reversed by WGP ß-glucan in oral squamous cell carcinoma.

The suppressive regulatory T cells (Treg) are frequently upregulated in cancer patients. This study aims to demonstrate the hypothesis that arecoline could induce the secretion of mitochondrial (mt) DNA D-loop and programmed cell death-ligand 1 (PD-L1) in extracellular vesicles (EVs), and attenuate T-cell immunity by upregulated Treg cell numbers. However, the immunosuppression could be reversed by whole glucan particle (WGP) ß-glucan in oral squamous cell (OSCC) patients. Arecoline-induced reactive oxygen specimen (ROS) production and cytosolic mtDNA D-loop were analyzed in OSCC cell lines. mtDNA D-loop, PD-L1, IFN-γ, and Treg cells were also identified for the surgical specimens and sera of 60 OSCC patients. We demonstrated that higher mtDNA D-loop, PD-L1, and Treg cell numbers were significantly correlated with larger tumor size, nodal metastasis, advanced clinical stage, and areca quid chewing. Furthermore, multivariate analysis confirmed that higher mtDNA D-loop levels and Treg cell numbers were unfavorable independent factors for survival. Arecoline significantly induced cytosolic mtDNA D-loop leakage and PD-L1 expression, which were packaged by EVs to promote immunosuppressive Treg cell numbers. However, WGP ß-glucan could elevate CD4+ and CD8+ T-cell numbers, mitigate Treg cell numbers, and promote oral cancer cell apoptosis. To sum up, arecoline induces EV production carrying mtDNA D-loop and PD-L1, and in turn elicits immune suppression. However, WGP ß-glucan potentially enhances dual effects on T-cell immunity and cell apoptosis and we highly recommend its integration with targeted and immune therapies against OSCC.

Quadruple UV LED Array for Facile, Portable, and Online Intrinsic Fluorescent Imaging of Protein in a Whole Gel Electrophoresis Chip.

Intrinsic fluorescence imaging (IFI) has been used for the stain-free detection of proteins in slab gel. However, complicated detection setups and small irradiation area limited the development of facile, online, and portable imaging of the whole slab gel. We here designed a quadruple UV LED array to produce even and powerful area light for direct irradiation of gel electrophoresis chip (GEC) at 275 nm. In addition, we only used a filter of 365 nm, a UV camera lens, and a CCD for IFI detection. We integrated the simple detection setup with the small GEC to construct the IFI-GEC device with a portable size of 15 × 15 × 38 cm. We detected three model proteins to demonstrate the good evenness of the LED array and the online imaging of the whole GEC. Furthermore, the reproducible IFI-GEC detection was completed within 10 min and the LOD was as low as 40 ng for lysozyme detection. All results indicated the potential of the IFI-GEC device for online and portable detection of proteins without staining.

Marker-Free Isoelectric Focusing Patterns for Identification of Meat Samples via Deep Learning.

Isoelectric focusing (IEF) is a powerful tool for resolving complex protein samples, which generates IEF patterns consisting of multiplex analyte bands. However, the interpretation of IEF patterns requires the careful selection of isoelectric point (pI) markers for profiling the pH gradient and a trivial process of pI labeling, resulting in low IEF efficiency. Here, we for the first time proposed a marker-free IEF method for the efficient and accurate classification of IEF patterns by using a convolutional neural network (CNN) model. To verify our method, we identified 21 meat samples whose IEF patterns comprised different bands of meat hemoglobin, myoglobin, and their oxygen-binding variants but no pI marker. Thanks to the high throughput and short assay time of the microstrip IEF, we efficiently collected 1449 IEF patterns to construct the data set for model training. Despite the absence of pI markers, we experimentally introduced the severe pH gradient drift into 189 IEF patterns in the data set, thereby omitting the need for profiling the pH gradient. To enhance the model robustness, we further employed data augmentation during the model training to mimic pH gradient drift. With the advantages of simple preprocessing, a rapid inference of 50 ms, and a high accuracy of 97.1%, the CNN model outperformed the traditional algorithm for simultaneously identifying meat species and cuts of meat of 105 IEF patterns, suggesting its great potential of being combined with microstrip IEF for large-scale IEF analyses of complicated protein samples.

Gel Electrophoresis Chip Using Joule Heat Self-Dissipation, Short Run Time, and Online Dynamic Imaging.

Gel electrophoresis (GE) is one of the most general tools in biomedicine. However, it suffers from low resolution, and its mechanism has not been fully revealed yet. Herein, we presented the dispersion model of w2 (t) ∝ Tt, showing the band dispersion (w) via temperature (T) and running time (t) control. Second, we designed an efficient GE chip via the time control and rapid Joule heat self-dissipation by thermal conductive plastic (TCP) and electrode buffer. Third, we conducted the simulations on TCP and polymethylmethacrylate (PMMA) chips, unveiling that (i) the temperature of TCP was lower than the PMMA one, (ii) the temperature uniformity of TCP was better than the PMMA one, and (iii) the resolution of TCP was superior to the PMMA one. Fourth, we designed both TCP and PMMA chips for experimentally validating the dispersion model, TCP chip, and simulations. Finally, we applied the TCP chip to thalassemia and model urine protein assays. The TCP chip has merits of high resolution, rapid run of 6-10 min, and low cost. This work paves the way for greatly improving electrophoretic techniques in gel, chip, and capillary via temperature and time control for biologic study, biopharma quality control, clinical diagnosis, and so on.

A facile online multi-gear capacitively coupled contactless conductivity detector for an automatic and wide range monitoring of high salt in HPLC.

Sensing the electrolyte solution or aqueous-organic mixture has attracted much interest in chemical separation, pharmaceutical engineering, bioprocess, and biochemical experiments. However, reports on online contactless sensor with automatic and wide range sensing of high content electrolyte have been rarely presented. Herein, a facile model and theory of online multi-gear capacitively coupled contactless conductivity detection (M-C4D) sensor was proposed using one excitation electrode and multiple detection electrodes. Further, the relevant digital computation based on the M-C4D theory was developed for parameter optimization: the electrode gap of 5-150 mm, inner radius of 0.25-0.75 mm, electrode length of 10-60 mm, and frequency of 40-250 kHz using MATLAB. To demonstrate the model, theory, and digital computation, liquid chromatography (LC) was chosen as the model of bioprocess, and the sensor was designed and used as an online sensing device for the automatic monitoring of high salt elution in LC. The experiments showed that (i) the detection results were in agreement with the digital data, validating the digital computation, theory, and model of M-C4D and (ii) the monitoring data of M-C4D were in agreement with those via the traditional meter, further validating the model and theory. Finally, the developed sensor was applied to the automated detection of high salt gradient in LC. In contrast to the currently used meters and C4D, the developed M-C4D sensor had the following merits: (i) facile and automatic online detection avoiding cumbersome manual switching of detector heads, (ii) fair linear range of 0.015-20 mS cm-1 (equivalently 0.1-159 mM KCl) that does not fit the range of traditional C4D, and (iii) fair accuracy of less than 1.50% relative error. All these results indicate that the developed model, theory, and sensor have potential for the process monitoring of high content electrolytes transfer in biochemical engineering and clinic pre-warning.

Model, Simulation, and Experiments on Moving Exchange Boundary via Ligand and Quantum Dots in Chip Electrophoresis.

Herein, the quench model of the moving exchange boundary (MEB) was first created via a ligand of 5,5'-dithiobis(2-nitro-benzoic acid) (DTNB) and group of 3-mercaptopropionic acid (MPA) capped on QDs, and then the recovery model was formed via MPA and 2-nitro-5-thiobenzoic acid (TNB) capped on QDs. The theory on MEB dynamics and width was developed based on the two reversible models, the simulation was conducted for the illumination of MEB, and the protocol was described for the MEB runs. The experiments revealed that (i) the quench model could be created via DTNB and MPA capped on QDs and the recovery one could be in situ formed via MPA and TNB capped on QDs, showing the feasibility of MEB models; (ii) the simulations on MEB dynamics and width were in coincidence with the theoretic predictions, showing the validity of two models; and (iii) the experiments demonstrated the validity of models, predictions, and simulations. The models and theory have potential for development of a biosensor, nanoparticle characterization, separation science, and an affinity assay of ligand-QDs.

Regulation of axon repulsion by MAX-1 SUMOylation and AP-3.

During neural development, growing axons express specific surface receptors in response to various environmental guidance cues. These axon guidance receptors are regulated through intracellular trafficking and degradation to enable navigating axons to reach their targets. In Caenorhabditis elegans, the UNC-5 receptor is necessary for dorsal migration of developing motor axons. We previously found that MAX-1 is required for UNC-5-mediated axon repulsion, but its mechanism of action remained unclear. Here, we demonstrate that UNC-5-mediated axon repulsion in C. elegans motor axons requires both max-1 SUMOylation and the AP-3 complex ß subunit gene, apb-3 Genetic interaction studies show that max-1 is SUMOylated by gei-17/PIAS1 and acts upstream of apb-3 Biochemical analysis suggests that constitutive interaction of MAX-1 and UNC-5 receptor is weakened by MAX-1 SUMOylation and by the presence of APB-3, a competitive interactor with UNC-5. Overexpression of APB-3 reroutes the trafficking of UNC-5 receptor into the lysosome for protein degradation. In vivo fluorescence recovery after photobleaching experiments shows that MAX-1 SUMOylation and APB-3 are required for proper trafficking of UNC-5 receptor in the axon. Our results demonstrate that SUMOylation of MAX-1 plays an important role in regulating AP-3-mediated trafficking and degradation of UNC-5 receptors during axon guidance.

Purification of low-abundance lysozyme in egg white via free-flow electrophoresis with gel-filtration chromatography.

As an effective separation tool, free-flow electrophoresis has not been used for purification of low-abundance protein in complex sample matrix. Herein, lysozyme in complex egg white matrix was chosen as the model protein for demonstrating the purification of low-content peptide via an FFE coupled with gel fitration chromatography (GFC). The crude lysozyme in egg while was first separated via free-flow zone electrophoresis (FFZE). After that, the fractions with lysozyme activity were condensed via lyophilization. Thereafter, the condensed fractions were further purified via a GFC of Sephadex G50. In all of the experiments, a special poly(acrylamide- co-acrylic acid) (P(AM-co-AA)) gel electrophoresis and a mass spectrometry were used for identification of lysozyme. The conditions of FFZE were optimized as follows: 130 µL/min sample flow rate, 4.9 mL/min background buffer of 20 mM pH 5.5 Tris-Acetic acid, 350 V, and 14 °C as well as 2 mg/mL protein content of crude sample. It was found that the purified lysozyme had the purity of 80% and high activity as compared with its crude sample with only 1.4% content and undetectable activity. The recoveries in the first and second separative steps were 65% and 82%, respectively, and the total recovery was about 53.3%. The reasons of low recovery might be induced by diffusion of lysozyme out off P(AM-co-AA) gel and co-removing of high-abundance egg ovalbumin. All these results indicated FFE could be used as alternative tool for purification of target solute with low abundance.

Photoacoustic imaging of cells in a three-dimensional microenvironment.

Imaging live cells in a three-dimensional (3D) culture system yields more accurate information and spatial visualization of the interplay of cells and the surrounding matrix components compared to using a two-dimensional (2D) cell culture system. However, the thickness of 3D cultures results in a high degree of scattering that makes it difficult for the light to penetrate deeply to allow clear optical imaging. Photoacoustic (PA) imaging is a powerful imaging modality that relies on a PA effect generated when light is absorbed by exogenous contrast agents or endogenous molecules in a medium. It combines a high optical contrast with a high acoustic spatiotemporal resolution, allowing the noninvasive visualization of 3D cellular scaffolds at considerable depths with a high resolution and no image distortion. Moreover, advances in targeted contrast agents have also made PA imaging capable of molecular and cellular characterization for use in preclinical personalized diagnostics or PA imaging-guided therapeutics. Here we review the applications and challenges of PA imaging in a 3D cellular microenvironment. Potential future developments of PA imaging in preclinical applications are also discussed.

Radiofrequency Ablation (RFA) Combined with Transcatheter Arterial Chemoembolization (TACE) for Patients with Medium-to-Large Hepatocellular Carcinoma: A Retrospective Analysis of Long-Term Outcome.

BACKGROUND The aim of this study was to investigate the prognostic value of radiofrequency ablation (RFA) plus transcatheter arterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) patients with tumor size ranging from 3.0 to 10.0 cm. MATERIAL AND METHODS We retrospectively analyzed data on 201 patients with medium-to-large HCC. According to treatment procedure, the patients were divided into the TACE group (n=124) and the TACE+RFA group (n=77). We recorded data on patient safety, subcapsular hepatic hematoma, large amount of ascites, liver abscess, gallbladder injury, and local skin infection. The overall survival (OS) and progression-free survival (PFS) in the 2 groups were analyzed and compared between groups. RESULTS The median PFS was 4.00 months (3.00-5.00 months) in the TACE group and 9.13 months (6.64-11.62 months) in the TACE+RFA group (P<0.001). Median OS was 12.00 months (8.88-15.13 months) in the TACE group and 27.57 months (20.06-35.08 months) in the TACE+RFA group (P<0.001). In the TACE+RFA group, multivariate Cox regression analysis showed that tumor size ≤5 cm) (HR: 1.952, 95% CI: 1.213-3.143, P=0.006), hepatitis B (HR: 2.323, 95% CI: 1.096-4.923, P=0.028), TACE times (1 or >1) (HR: 1.867, 95% CI: 1.156-3.013, P=0.011), alpha-fetoprotein (AFP) level >200 ng/ml (HR: 2.426, 95% CI: 1.533-3.839, P<0.001), and AST level >40 U/L (HR: 1.946, 95% CI: 1.196-3.166, P=0.007) were independent prognostic factors for overall survival. CONCLUSIONS Combination therapy of TACE with RFA is a safe and effective treatment for patients with medium-to-large HCC, with the long-term beneficial effect of retarding tumor progression and improving PFS and OS.

Enhanced Radiosensitization for Cancer Treatment with Gold Nanoparticles through Sonoporation.

We demonstrate the megavoltage (MV) radiosensitization of a human liver cancer line by combining gold-nanoparticle-encapsulated microbubbles (AuMBs) with ultrasound. Microbubbles-mediated sonoporation was administered for 5 min, at 2 h prior to applying radiotherapy. The intracellular concentration of gold nanoparticles (AuNPs) increased with the inertial cavitation of AuMBs in a dose-dependent manner. A higher inertial cavitation dose was also associated with more DNA damage, higher levels of apoptosis markers, and inferior cell surviving fractions after MV X-ray irradiation. The dose-modifying ratio in a clonogenic assay was 1.56 ± 0.45 for a 10% surviving fraction. In a xenograft mouse model, combining vascular endothelial growth factor receptor 2 (VEGFR2)-targeted AuMBs with sonoporation significantly delayed tumor regrowth. A strategy involving the spatially and temporally controlled release of AuNPs followed by clinically utilized MV irradiation shows promising results that make it worthy of further translational investigations.

Emerging erm(B)-Mediated Macrolide Resistance Associated with Novel Multidrug Resistance Genomic Islands in Campylobacter.

The rapid dissemination of the macrolide resistance gene erm(B) will likely compromise the efficacy of macrolides as the treatment of choice for campylobacteriosis. More importantly, erm(B) is always associated with several multidrug resistance genomic islands (MDRGIs), which confer resistance to multiple other antimicrobials. Continuous monitoring of the emergence of erm(B) and analysis of its associated genetic environments are crucial for our understanding of macrolide resistance in Campylobacter In this study, 290 Campylobacter isolates (216 Campylobacter coli isolates and 74 Campylobacter jejuni isolates) were obtained from 1,039 fecal samples collected in 2016 from pigs and chickens from three regions of China (344 samples from Guangdong, 335 samples from Shanghai, and 360 samples from Shandong). Overall, 74 isolates (72 C. coli isolates and 2 C. jejuni isolates) were PCR positive for erm(B). Combined with data from previous years, we observed a trend of increasing prevalence of erm(B) in C. coli Pulsed-field gel electrophoresis analyses suggested that both clonal expansion and horizontal transmission were involved in the dissemination of erm(B) in C. coli, and three novel types of erm(B)-associated MDRGIs were identified among the isolates. Furthermore, 2 erm(B)-harboring C. jejuni isolates also contained an aminoglycoside resistance genomic island and a multidrug-resistance-enhancing efflux pump, encoded by RE-cmeABC Antimicrobial susceptibility testing showed that most of the isolates were resistant to all clinically important antimicrobial agents used for the treatment of campylobacteriosis. These findings suggest that the increasing prevalence of erm(B)-associated MDRGIs might further limit treatment options for campylobacteriosis.

Facile Counting of Ligands Capped on Nanoparticles via a Titration Chip of Moving Reaction Boundary Electrophoresis.

Absolute quantification of ligand capped on the surface of nanoparticles (NPs) has faced a great challenge without the use of complex inner standards (CIS). Herein, we proposed a facile electrophoresis titration (ET) model, designed an ET device, and developed a relevant method for counting the ligand on NPs without the use of CIS, based on moving reaction boundary (MRB). Furthermore, we conducted the relevant ET runs by using 3-mercaptopropionic acid (MPA) and quantum dots (QDs) as the model ligand and NPs, respectively. The experiments revealed that the ligand content of 1518 ± 295 obtained via an ET was close to the one of 1408 ± 117 determined via NMR, validating the ET model. Moreover, the experiments showed fair stability (RSD < 5.62%) and simplicity of ET without the use of CIS. Evidently, the ET model opens a window for facile assay of ligand capped on NPs.

Characterization of multiresistance gene cfr(C) variants in Campylobacter from China.

OBJECTIVES: To investigate the occurrence, the genetic environment and the functionality of novel variants of the MDR gene cfr(C) in Campylobacter from China. METHODS: A total of 370 Campylobacter isolates of porcine and chicken origin collected from three regions of China in 2015 were screened for cfr(C) by PCR. The phenotypes and genotypes of cfr(C)-positive isolates were investigated by antimicrobial susceptibility testing, PFGE, MLST, S1-PFGE, Southern blotting and WGS. Quantitative RT-PCR was used to compare the expression levels of the cfr(C) variants in their original isolate and clone constructs in Campylobacter jejuni NCTC 11168. RESULTS: Four (1.1%) porcine Campylobacter coli isolates were positive for cfr(C). They failed to show elevated MICs of phenicols. The deduced Cfr(C) sequences identified exhibited 2-6 amino acid changes compared with the original Cfr(C) reported in the USA. Cloning of the cfr(C) variant genes into C. jejuni NCTC 11168 resulted in ≥32-fold increases in the MICs of phenicols, indicating that the cfr(C) variant genes are functional. The cfr(C)-carrying isolates belonged to three genotypes and WGS analysis revealed the cfr(C) genes were chromosomally located in MDR genomic islands, which contained multiple antibiotic resistance genes of Gram-positive origin. CONCLUSIONS: This study identified chromosomal cfr(C) genes in C. coli isolates from China. They appeared functionally dormant in the original isolates but were fully functional when cloned and expressed in C. jejuni. The cfr(C) genes were co-transferred with other antibiotic resistance genes, possibly from Gram-positive bacteria. These findings reveal new insights into the function and transmission of cfr(C) in Campylobacter.

A facile isoelectric focusing of myoglobin and hemoglobin used as markers for screening of chicken meat quality in China.

A novel analytical protocol was developed for general quality screening of chicken meat based on IEF and protein extraction. To demonstrate the developed protocol, 24 chickens were divided into three groups; each had eight chickens. The chickens in Group 1 were slaughtered by exsanguination, Group 2 asphyxiated in water, and that in Group 3 were infected by new castle disease virus. Proteins were extracted from the meat samples by using pure water as an extractant, separated by IEF, verified by western blot, and quantified via imaging analysis. The relevant experiments demonstrated that two myoglobin (Mb) bands were detected at pI 6.8 and 7.04 for all samples of Groups 1, 2, and 3, but there were additional hemoglobin (Hb) bands at pI 7.09 and 7.13 (P < 0.05) for the samples of Groups 2 and 3. The results implied that Hb bands might be a potential biomarker for the screening of chicken meat quality. The RSD values of two Mb bands (pI 6.8 and 7.04) in Group 1 were respectively 4.08 and 3.63%, the ones of two Hb bands (pI 7.09 and 7.13) in Group 2 were 3.66 and 2.10%, and those in Group 3 were 2.17% and 2.77%, respectively. All the RSD values indicated high stability and reliability of the developed protocol. Additionally, the protocol had a direct readout of protein bands in IEF without staining. However, it was time-consuming and had high cost. Even so, the relevant general method and finding have potential for screening of chicken meat quality.

Study of diffusive- and convective-transport mediated microtumor growth in a controlled microchamber.

In this paper, we report on using mass transport to control nutrition supply of colorectal cancer cells for developing a microtumor in a confined microchamber. To mimic the spatial heterogeneity of a tumor, two microfluidic configurations based on resistive circuits are designed. One has a convection-dominated microchamber to simulate the tumor region proximal to leaky blood vessels. The other has a diffusion-dominated microchamber to mimic the tumor core that lacks blood vessels and nutrient supply. Thus, the time for nutrition to fill the microchamber can vary from tens of minutes to several hours. Results show that cells cultured under a diffusive supply of nutrition have a high glycolytic rate and a nearly constant oxygen consumption rate. In contrast, cells cultured under convective supply of nutrition have a gradual increase of oxygen consumption rate with a low glycolytic rate. This suggests that cancer cells have distinct reactions under different mass transport and nutrition supply. Using these two microfluidic platforms to create different rate of nutrition supply, it is found that a continuous microtumor that almost fills the mm-size microchamber can be developed under a low-nutrient supply environment, but not for the convective condition. It also is demonstrated that microchannels can simulate the delivery of anti-cancer drugs to the microtumor under controlled mass-transport. This method provides a means to develop a larger scale microtumor in a lab-on-a-Chip system for post development and stimulations, and microchannels can be applied to control the physical and chemical environment for anti-cancer drug screening.

Simple Chip Electrophoresis Titration of Neutralization Boundary with EDTA Photocatalysis for Distance-Based Sensing of Melamine in Dairy Products.

Melamine was sometimes adulterated to dairy products for false protein content increase in developing countries. However, a portable sensor has not been developed for on-spot determination of melamine in dairy products yet. Herein, a distance-based sensor was advanced for the quantification of melamine in dairy products based on chip electrophoretic titration (ET) of moving neutralization boundary (NB) and EDTA photocatalysis. In the chip sensor, EDTA, H2O2, and leucomalachite green (LMG) were added in the anode well. Under UV light, EDTA photocatalyzes H2O2 and colorless LMG as H2O and color malachite green (MG) with one positive charge. When applying an electric field, the MG in the anode well migrated into the channel and was neutralized with the base in the channel, resulting in colorless MG-OH and NB. If the melamine-content dairy sample was added into the EDTA-H2O2-LMG system, H2O2 reacts with melamine, leading to the decrease of MG. Thus, the higher the melamine content in dairy products, the shorter the distance of NB migration under the given time, implying a distance-based sensor of melamine. A series of experiments manifested the validity of ET-NB sensor for detection of melamine. Moreover, the results revealed the numerous merits of ET-NB sensor, such as good selectivity, high sensitivity (LOD down to 0.20 µM for milk and 0.10 µM for infant formula vs the FDA safety limits of 20 µM for milk and 8.0 µM for infant formula), good repeatability and recoveries (87-108% for milk, 90-107% for formula). Particularly, the cell phone-like sensor was portable, simple (no any pretreatment), rapid (within 15 min), as well as low cost, to evaluate the quality of dairy products. The developed sensor has great potential in on-spot detection of melamine in dairy products as well as other analytes, at which we are testing in our lab.

Gut-derived cholecystokinin contributes to visceral hypersensitivity via nerve growth factor-dependent neurite outgrowth.

BACKGROUND AND AIM: Irritable bowel syndrome is characterized by abdominal pain and altered bowel habits and may occur following stressful events or infectious gastroenteritis such as giardiasis. Recent findings revealed a link between cholecystokinin (CCK), neurotrophin synthesis, and intestinal hyperalgesia. The aim was to investigate the role of CCK in visceral hypersensitivity using mouse models challenged with a bout of infection with Giardia lamblia or psychological stress, either alone or in combination. METHODS: Abdominal pain was evaluated by visceromoter response to colorectal distension. Nerve fibers in intestinal tissues were stained using immunohistochemistry (PGP9.5). Human neuroblastoma SH-SY5Y cells incubated with bacterial-free mouse gut supernatant or recombinant CCK-8S were assessed for neurite outgrowth and nerve growth factor (NGF) production. RESULTS: Intestinal hypersensitivity was induced by either stress or Giardia infection, and a trend of increased pain was seen following dual stimuli. Increased CCK levels and PGP9.5 immunoreactivity were found in colonic mucosa of mice following stress and/or infection. Inhibitors to the CCK-A receptor (L-364718) or CCK-B receptor (L-365260) blocked visceral hypersensitivity caused by stress, but not when induced by giardiasis. Nerve fiber elongation and NGF synthesis were observed in SH-SY5Y cells after incubation with colonic supernatants from mice given the dual stimuli, or after treatment with CCK-8S. Increased nerve fiber length by colonic supernatant and CCK-8S was attenuated by L-365260 or neutralizing anti-NGF. CONCLUSIONS: This new model successfully recapitulates intestinal hypernociception induced by stress or Giardia. Colonic CCK contributes to visceral hypersensitivity caused by stress, but not by Giardia, partly via NGF-dependent neurite outgrowth.

High-resolution nucleic acid detection using online polyacrylamide gel electrophoresis platform.

Polyacrylamide gel electrophoresis (PAGE) is one of the most popular techniques for the separation and detection of nucleic acids. However, it requires a complicated detection procedure and offline detection format, which inevitably leads to band broadening and thus compromises the separation resolution. To overcome this problem, we developed an online PAGE (OPAGE) platform by integrating the gel electrophoresis apparatus with the gel imaging system, so as to obviate the need for the complicated detection procedure. Notably, OPAGE enabled the real-time monitoring of the separation process and the immediate imaging of the separation results once the electrophoresis ended. Using a series of synthetic DNAs with different lengths as samples, we demonstrated that the OPAGE platform enhanced 32-64 % of the number of theoretical plates, showed a robust dynamic range of 0.1-12.5 ng/µL, and realized a limit of detection as low as 0.08 ng/µL DNA. Based on our results, we anticipate that the OPAGE platform is a promising alternative to traditional nucleic acid gel electrophoresis for simple and high-resolution detection and quantification and nucleic acid.

Spatially controlled diffusion range of tumor-associated angiogenic factors to develop a tumor model using a microfluidic resistive circuit.

Developing a tumor model with vessels has been a challenge in microfluidics. This difficulty is because cancer cells can overgrow in a co-culture system. The up-regulation of anti-angiogenic factors during the initial tumor development can hinder neovascularization. The standard method is to develop a quiescent vessel network before loading a tumor construct in an adjacent chamber, which simulates the interaction between a tumor and its surrounding vessels. Here, we present a new method that allows a vessel network and a tumor to develop simultaneously in two linked chambers. The physiological environment of these two chambers is controlled by a microfluidic resistive circuit using two symmetric long microchannels. Applying the resistive circuit, a diffusion-dominated environment with a small 2-D pressure gradient is created across the two chambers with velocity <10.9 nm s-1 and Péclet number <6.3 × 10-5. This 2-D pressure gradient creates a V-shaped velocity clamp to confine the tumor-associated angiogenic factors at pores between the two chambers, and it has two functions. At the early stage, vasculogenesis is stimulated to grow a vessel network in the vessel chamber with minimal influence from the tumor that is still developed in the adjacent chamber. At the post-tumor-development stage, the induced steep concentration gradient at pores mimics vessel-tumor interactions to stimulate angiogenesis to grow vessels toward the tumor. Applying this method, we demonstrate that vasculogenic vessels can grow first, followed by stimulating angiogenesis. Angiogenic vessels can grow into stroma tissue up to 1.3 mm long, and vessels can also grow into or wrap around a 625 µm tumor spheroid or a tumor tissue developed from a cell suspension. In summary, our study suggests that the interactions between a developing vasculature and a growing tumor must be controlled differently throughout the tissue development process, including at the early stage when vessels are still forming and at the later stage when the tumor needs to interact with the vessels.