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Articles by Kan Liu in JoVE

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Microwave-assisted One-pot Synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB)


JoVE 2755 6/28/2011

1Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles, 2Crump Institute for Molecular Imaging, David Geffen School of Medicine, University of California at Los Angeles, 3California NanoSystems Institute, University of California at Los Angeles, 4Nuclear Medicine, PET Center, Shanghai Medical Collegea, Fudan University, 5Electronics and Information Engineering, College of Electronics and Information Engineering, Wuhan Textile University

A facile, one-pot synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB) was developed based on a non-aqueous, three-step radiochemical process. Using microwave heating, the entire procedure can be completed in less than 30 min, or 60 min with further purification by preparative HPLC. The decay-corrected radiochemical yields (RCYs) were 35-5% (n > 30).

Other articles by Kan Liu on PubMed

Streptozotocin, an O-GlcNAcase Inhibitor, Blunts Insulin and Growth Hormone Secretion

Type 2 diabetes mellitus results from a complex interaction between nutritional excess and multiple genes. Whereas pancreatic beta-cells normally respond to glucose challenge by rapid insulin release (first phase insulin secretion), there is a loss of this acute response in virtually all of the type 2 diabetes patients with significant fasting hyperglycemia. Our previous studies demonstrated that irreversible intracellular accumulation of a glucose metabolite, protein O-linked N-acetylglucosamine modification (O-GlcNAc), is associated with pancreatic beta-cell apoptosis. In the present study, we show that streptozotocin (STZ), a non-competitive chemical blocker of O-GlcNAcase, induces an insulin secretory defect in isolated rat islet cells. In contrast, transgenic mice with down-regulated glucose to glucosamine metabolism in beta-cells exhibited an enhanced insulin secretion capacity. Interestingly, the STZ blockade of O-GlcNAcase activity is also associated with a growth hormone secretory defect and impairment of intracellular secretory vesicle trafficking. These results provide evidence for the roles of O-GlcNAc in the insulin secretion and possible involvement of O-GlcNAc in general glucose-regulated hormone secretion pathways.

Liposome-mediated Transfer of Vascular Endothelial Growth Factor CDNA Augments Survival of Random-pattern Skin Flaps in the Rat

Tissue engineering is an application for gene therapy that is in its infancy. We show that simple liposomal-mediated gene transfer could result in a potentially useful biological effect in the field of wound healing. cDNA encoding the 165 amino acid form of vascular endothelial growth factor complexed to commercially available liposomes was injected into rat skin 1 week before raising a random pattern 3 x 10 cm flap. The flap survival was enhanced by 14 percent, and was accomplished without accessing the arterial inflow of the territory. These results were statistically significant (p<0.002) and reproducible. No adverse effects were seen. Histological analysis of the angiogenesis localized much of the new vessel formation to the area around the hair follicles. Polymerase chain reaction amplification of extracted flap tissue confirmed the presence of the transgene.

Accumulation of Protein O-GlcNAc Modification Inhibits Proteasomes in the Brain and Coincides with Neuronal Apoptosis in Brain Areas with High O-GlcNAc Metabolism

All tissues contain the enzymes that modify and remove O-GlcNAc dynamically from nucleocytoplasmic proteins. These enzymes have been shown to play a role in the control of transcription, vesicular trafficking and, more recently, proteasome function. Modification by O-GlcNAc of the 19S cap of the proteasome inhibits proteasomal function. Transcripts of both O-GlcNAc transferase and O-GlcNAcase are very abundant in the brain, with the highest concentrations in hippocampal neurons and Purkinje cells. When the on-rate of modification is favored over the off-rate by intraventricular administration of a drug, streptozocin, these areas of the brain display the most rapid accumulation of O-GlcNAc. Cerebral proteasome function is reduced and ubiquitin and p53 accumulate in these brain regions, with the subsequent activation of a p53-dependent transgene and the endogenous Mdm2 gene. Later, some hippocampal cells, but not Purkinje cells, undergo apoptosis. These observations suggest that the O-GlcNAc system may participate in neurodegeneration, particularly in the hippocampus.

Proteolytic Processing of TGFalpha Redirects Its Mitogenic Activity: the Membrane-anchored Form is Autocrine, the Secreted Form is Paracrine

Wild-type transforming growth factor alpha (TGFalpha) expression in lactotrope cells in the pituitary gland led to lactotrope-specific pituitary hyperplasia and adenomata. To indicate whether the EGF receptor is involved in this TGFalpha-mediated phenotype, we bred TGFalpha mice with mice expressing the cytoplasmic truncated-EGF receptor (EGFR-tr), which is dominant-negative in other models. These bitransgenic mice developed pituitary pathology despite expression of the dominant-negative receptor. To further characterize this observation, we generated two lineages of transgenic mice that overexpress mutant forms of TGFalpha: a processed soluble form (s TGFalpha) and a cytoplasmic-deleted form (TGFalphaDeltaC). While sTGFalpha expression in lactotrope cells failed to induce autocrine lactotrope hyperplasia, the pituitary became very enlarged due to proliferation of neighboring interstitial cells. In contrast, the TGFalphaDeltaC mice did not develop a phenotype, although the mRNA and protein were present in the pituitary and this form of TGFalpha was confirmed to be biologically active and targeted properly to the plasma membrane of cultured CHO cells. The results suggest that the cytoplasmic domain of TGFalpha is required for autocrine parenchymal tumor formation in the pituitary gland. This signal cannot be inhibited by the EGFR-tr. Conversely, the released form of TGFalpha appears to have primarily paracrine activity.

[Factors Affecting the Prognosis of Diffuse Large B-cell Lymphoma in Chinese]

To study the correlation between clinical prognosis and clinicopathologic features, origin and cell proliferous index of diffuse large B-cell lymphoma (DLBCL) in China.

Efficacy of Combination Gene Therapy with Multiple Growth Factor CDNAs to Enhance Skin Flap Survival in a Rat Model

The objective of this study was to investigate the efficacy of combination gene therapy with multiple angiogenic growth factor cDNAs to enhance survival of ischemic skin flaps in a rat model. Sixty Sprague-Dawley rats were divided into six groups. Varying combinations of VEGF165, PDGF-B, and bFGF-plasmids were injected to prefabricate the flaps. Random skin flaps were raised on the dorsal aspect of rats following prefabrication with growth factor cDNAs. Flap viability was determined by measurement of percentage area of survival. The efficacy of gene therapy was evaluated by flap survival and neovascularization of representative histologic sections stained immunohistologically. The VEGF165 plus bFGF cDNAs enhanced the viability of the flap and neovascularization most effectively; the flap survival area was 64.3 +/- 8.7% after transfer of these two growth factor genes. Addition of PDGF-B cDNA is deleterious to the effects of combined VEGF165 and bFGF, leading to a significant decrease in flap viability (44.9 +/- 2.7%). Viability of the flaps with combined VEGF165 and bFGF cDNA transfer was significantly greater than that of the flaps with VEGF165 transfer alone (57.6 +/- 5.2%) or sham plasmid control (52.3 +/- 5.0%). Combined transfer of VEGF165 and bFGF cDNA is the most effective combination of multiple growth factor genes to improve flap viability in this model. Simultaneous transfer of three growth factor genes (VEGF165, PDGF-B, and bFGF) is deleterious to flap survival, at least for the ratio of lipofectin:transgene employed.

Shape-controlled Production of Biodegradable Calcium Alginate Gel Microparticles Using a Novel Microfluidic Device

In this paper we describe a novel method of manufacturing shape-controlled calcium alginate gel microparticles in a microfluidic device. Both manufacturing shape-controlled microparticles and synthesizing hydrogel microparticles could be performed simultaneously in the microfluidic device. The novel microfluidic device comprised of two individual flow-focusing channels and a synthesizing channel was successfully applied as a continuous microfluidic reactor to synthesize gel microparticles with size and shape control. By passive control based on the microchannel geometric confinement and liquid-phase flow rates, we succeeded in producing monodisperse sodium alginate microparticles with diverse shapes (such as plugs, disks, microspheres, rods, and threads) in the flow-focusing channels of the microfluidic device. The shape and size of the sodium alginate microparticles could be tuned by adjusting the flow rates of the various streams. Further stages of the chemical reaction could be initiated by mixing sodium alginate microparticles and calcium chloride (CaCl2) solution in the synthesizing channel. The shapes of the sodium alginate microparticles could be permanently preserved by the synthesis of calcium alginate gel microparticles. The preparation conditions of size- and shape-controlled calcium alginate microparticles and influence factors were studied.

Effect of a Convenient Single 90-mg Pamidronate Dose on Biochemical Markers of Bone Metabolism in Patients with Acute Spinal Cord Injury

To describe the biochemical and adverse effects of a convenient single 90 mg pamidronate dose in patients with acute spinal cord injury (SCI) and compare these effects with those observed in a previous similar study using a 30 mg/d x 3-day pamidronate dosing regimen.

Biochemical Properties of C78SC96S RhFGF-2: a Double Point-mutated RhFGF-2 Increases Obviously Its Activity

Fibroblast growth factor-2 (FGF-2) is a multifunctional polypeptide that affects many cellular functions and phenomena. The wild-type recombinant human fibroblast growth factor rhFGF-2(W) and the mutant C78SC96S rhFGF-2(M) were expressed in Escherichia coli and their products were purified. The results by the means of fluorescence spectroscopy and CD spectrums, suggested that due to its decreased hydrophobicity rhFGF-2 is not deposited as an inclusion body. The mitogenic activity of the expressed rhFGF-2(M) on 3T3 fibroblasts was shown to be 10-fold more than the expressed rhFGF-2(W) of which the biological activity was a little less than that of the standard rhbFGF(W), indicating that the increased biological activity was due to the change of its secondary structure, dimerization and affinity binding to FGF receptor (FGFR).

Flow-focusing Generation of Monodisperse Water Droplets Wrapped by Ionic Liquid on Microfluidic Chips: from Plug to Sphere

Generating droplets via microfluidic chips is a promising technology in microanalysis and microsynthesis. To realize room-temperature ionic liquid (IL)-water two-phase studies in microscale, a water-immiscible IL was employed as the continuous phase for the first time to wrap water droplets (either plugs or spheres) on flow-focusing microfluidic chips. The IL, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), could wet both hydrophilic and hydrophobic channel surfaces because of its dual role of hydrophilicity/hydrophobicity and extremely high viscosity, thus offering the possibility of wrapping water droplets in totally hydrophilic (THI), moderately hydrophilic (MHI), and hydrophobic (HO) channels. The droplet shape could be tuned from plug to sphere, with the volume from 6.3 nL to 65 pL, by adding an orifice in the focusing region, rendering the hydrophilic channel surface hydrophobic, and suppressing the Uw/UIL ratio below 1.0. Three different breakup processes were defined and clarified, in which the sub-steady breakup and steady breakup were essential for the formation of plugs and spheric droplets, respectively. The influences of channel hydrophilicity/hydrophobicity on droplet formation were carefully studied by evaluating the wetting abilities of water and IL on different surfaces. The superiority of IL over water in wetting hydrophobic surface led to the tendency of forming small, spheric aqueous droplets in the hydrophobic channel. This IL-favored droplet-based system represented a high efficiency in water/IL extraction, in which rhodamine 6G was extracted from aqueous droplets to [BMIM][PF6] in the hydrophobic orifice-included (HO-OI) channel in 0.51 s.

Propofol Causes Less Postoperative Pharyngeal Morbidity Than Thiopental After the Use of a Laryngeal Mask Airway

The insertion of a laryngeal mask airway (LMA) may result in postoperative sore throat. The choice of induction drug on airway morbidity after LMA insertion may be important. We performed this study to compare the incidence of postoperative pharyngeal morbidity after the insertion of a LMA in 340 patients administered either 2 mg/kg propofol (group P) or thiopental 5 mg/kg (group T) for induction of anesthesia. Patients were maintained at 1-2 minimum alveolar anesthetic concentration sevoflurane in 50% oxygen/air. Spontaneous or assisted spontaneous ventilation was maintained. An investigator blinded to group allocation visited patients at 2, 12, and 24 h postoperatively. Adverse responses were noted (yes/no) at each time point including sore throat, sore mouth, sore jaw, hoarseness, dysphonia, and dysphagia. At 2 h postoperatively, the incidence of sore throat, dysphagia, and postoperative nausea and vomiting in group T was higher than in group P (24% vs 13% for sore throat, 15% vs 3% for dysphagia, 20% vs 11% for nausea, 14% vs 6% for vomiting, P < 0.05). The number-needed-to-treat to prevent sore throat and dysphagia was 10 and 8, respectively (95% confidence intervals, 5-43). We concluded that, when propofol, rather than thiopental, is used for the induction of anesthesia, it results in a lower incidence of early pharyngeal morbidity and postoperative nausea and vomiting after the insertion of a LMA.

A Hydrodynamically Focused Stream As a Dynamic Template for Site-specific Electrochemical Micropatterning of Conducting Polymers

Repetitive Hyperbaric Oxygen Exposures Enhance Sensitivity to Convulsion by Upregulation of ENOS and NNOS

Repetitive hyperbaric oxygen (HBO) exposures as preconditioning methods produce ischemic tolerance, but may increase the risk of convulsions in patients. The purpose of this study was to investigate the mechanisms in increased sensitivity to convulsions and the role of nitric oxide (NO) and its synthases after repetitive HBO exposures.

A Dynamic Micromixer for Arbitrary Control of Disguised Chemical Selectivity

A new type of dynamic micromixer combining the concepts of parallel multi-lamination and hydrodynamic focusing was developed for arbitrary control of disguised chemical selectivity.

Neuroprotective Effects of Hydrogen Saline in Neonatal Hypoxia-ischemia Rat Model

Cerebral hypoxia-ischemia (HI) represents a major cause of brain damage in the term newborn. This study aimed to examine the short and long-term neuroprotective effect of hydrogen saline (H(2) saline) using an established neonatal HI rat pup model. Seven-day-old rat pups were subjected to left common carotid artery ligation and then 90 min hypoxia (8% oxygen at 37 degrees C). H(2) saturated saline was administered by peritoneal injection (5 ml/kg) immediately and again at 8 h after HI insult. At 24 h after HI, the pups were decapitated and brain morphological injury was assessed by 2,3,5-triphenyltetrazolium chloride (TTC), Nissl, and TUNEL staining. Acute cell death, inflammation and oxidative stress were evaluated at 24 h by studying caspase-3 activity, MDA measurement as well as Iba-1 immunochemistry in the brain. At 5 weeks after HI, spontaneous activity test and Morris water maze test were conducted. We observed that H(2) saline treatment reduced the caspase activity, MDA, Iba-1 levels, the infarct ratio, and improved the long-term neurological and neurobehavioral functions. H(2) saline has potentials in the clinical treatment of HI and other ischemia-related cerebral diseases.

Analysis and Comparison of a Set of Expressed Sequence Tags of the Parthenogenetic Water Flea Daphnia Carinata

The water flea Daphnia carinata (D. carinata) reproduces both sexually and parthenogenetically, yet little is known about the genes involved in these processes. To further clarify the reproductive biology of Daphnia and elucidate their unique mechanism of reproductive transformation, we have generated and characterized an expressed sequence tag (EST) data set from D. carinata. A set of 1,495 clusters were generated from sequencing 3,072 randomly chosen clones from a parthenogenetic, juvenile water flea cDNA library. The nucleic acid and deduced amino acid sequences were compared with known GenBank sequences. Functional annotation found that 959 clusters showed significant homology with known genes involved in a broad range of activities, including metabolism, translation, development and reproduction, as well as genes involved in sensing environmental factors. We speculate that genes involved in development and reproduction, along with genes that allow the organism to sense changes in the environment, play important roles in the process of parthenogenetic reproduction and could be markers of the early steps of sexual differentiation. Additionally, 86% of the D. Carinata unique sequences could be stringently mapped to the D. pulex genome, of which 125 mapped to intergenic and intronic regions on the current assembly. Our results provide practical insight into crustacean reproductive biology, in addition to establishing a new animal model for reproductive and developmental biology.

A Novel Type of Dual-modality Molecular Probe for MR and Nuclear Imaging of Tumor: Preparation, Characterization and in Vivo Application

A novel dual-modality molecular probe composed of biocompatible Fe(3)O(4) nanocrystal, monoclonal antibody and radionuclide was designed and prepared. All functional components in the dual-modality molecular probe, i.e., Fe(3)O(4), PEG, mAb 3H11 and (125)I, were chemically bonded together for forming a stable molecular probe. Systematic in vitro experiments were carried out for evaluating the biological activity of the antibody in the targeting probe. A series of in vivo experiments were performed based on the dual-modality imaging probe for detecting xenografted tumors in nude mice by MRI and gamma-imaging techniques. The pharmacokinetics of the dual-modality molecular probe in tumor-bearing nude mice was studied.

Structural Basis for Proteolytic Specificity of the Human Apoptosis-inducing Granzyme M

Granzyme M (GzmM), a unique serine protease constitutively expressed in NK cells, is important for granule-mediated cytolysis and can induce rapid caspase-dependent apoptosis of tumor cells. However, few substrates of GzmM have been reported to date, and the mechanism by which this enzyme recognizes and hydrolyzes substrates is unknown. To provide structural insights into the proteolytic specificity of human GzmM (hGzmM), crystal structures of wild-type hGzmM, the inactive D86N-GzmM mutant with bound peptide substrate, and the complexes with a catalytic product and with a tetrapeptide chloromethylketone inhibitor were solved to 1.96 A, 2.30 A, 2.17 A and 2.70 A, respectively. Structure-based mutagenesis revealed that the N terminus and catalytic triad of hGzmM are most essential for proteolytic function. In particular, D86N-GzmM was found to be an ideal inactive enzyme for functional studies. Structural comparisons indicated a large conformational change of the L3 loop upon substrate binding, and suggest this loop mediates the substrate specificity of hGzmM. Based on the complex structure of GzmM with its catalytic product, a tetrapeptide chloromethylketone inhibitor was designed and found to specifically block the catalytic activity of hGzmM.

An Integrated Microfluidic Device for Large-scale in Situ Click Chemistry Screening

An integrated microfluidic device has been developed to perform 1024 in situ click chemistry reactions in parallel using the bovine carbonic anhydrous II (bCAII) click chemistry system as a proof-of-concept study and a rapid hit identification approach using SPE purification and electrospray-ionization mass spectrometry, multiple reaction monitoring (MRM) analysis, all of which improves the sensitivity and throughput of the downstream analysis.

Cerenkov Radiation Imaging As a Method for Quantitative Measurements of Beta Particles in a Microfluidic Chip

It has been observed that microfluidic chips used for synthesizing (18)F-labeled compounds demonstrate visible light emission without nearby scintillators or fluorescent materials. The origin of the light was investigated and found to be consistent with the emission characteristics from Cerenkov radiation. Since (18)F decays through the emission of high-energy positrons, the energy threshold for beta particles, i.e. electrons or positrons, to generate Cerenkov radiation was calculated for water and polydimethylsiloxane (PDMS), the most commonly used polymer-based material for microfluidic chips. Beta particles emitted from (18)F have a continuous energy spectrum, with a maximum energy that exceeds this energy threshold for both water and PDMS. In addition, the spectral characteristics of the emitted light from (18)F in distilled water were also measured, yielding a broad distribution from 300 nm to 700 nm, with higher intensity at shorter wavelengths. A photograph of the (18)F solution showed a bluish-white light emitted from the solution, further suggesting Cerenkov radiation. In this study, the feasibility of using this Cerenkov light emission as a method for quantitative measurements of the radioactivity within the microfluidic chip in situ was evaluated. A detector previously developed for imaging microfluidic platforms was used. The detector consisted of a charge-coupled device (CCD) optically coupled to a lens. The system spatial resolution, minimum detectable activity and dynamic range were evaluated. In addition, the calibration of a Cerenkov signal versus activity concentration in the microfluidic chip was determined. This novel method of Cerenkov radiation measurements will provide researchers with a simple yet robust quantitative imaging tool for microfluidic applications utilizing beta particles.

A Small Library of DNA-encapsulated Supramolecular Nanoparticles for Targeted Gene Delivery

We demonstrated a convenient, flexible and modular synthetic approach for preparation of a small library of DNA-encapsulated supramolecular nanoparticles SNPs superset DNA and RGD-SNPs superset DNA with different sizes and RGD target ligand coverage for targeted gene delivery.

A Novel Role for Minimal Introns: Routing MRNAs to the Cytosol

Introns and their splicing are tightly coupled with the subsequent mRNA maturation steps, especially nucleocytoplasmic export. A remarkable fraction of vertebrate introns have a minimal size of about 100 bp, while majority of introns expand to several kilobases even megabases in length.

[Preliminary Application of Diffusion-weighted Imaging with 3.0 T Magnetic Resonance Scanner for Nasopharyngeal Carcinoma]

To evaluate the clinical value of diffusion-weighted imaging (DWI) with 3.0 T magnetic resonance scanner for nasopharyngeal carcinoma (NPC) and to explore the appropriate b value during this procedure.

Hyperbaric Oxygen Preconditioning Reduces the Incidence of Decompression Sickness in Rats Via Nitric Oxide

Divers are at risk of decompression sickness (DCS) when the ambient pressure decrease exceeds a critical threshold. Hyperbaric oxygen (HBO2) preconditioning has been used to prevent various injuries, but the protective effect on DCS has not been well explored. To investigate the prophylactic effect of HBO2 on DCS, rats were pretreated with HBO2 (250 kPa-60 minutes) (all the pressures described here are absolute pressure) for 18 hours before a simulated air dive (700 kPa-100 minutes) with fast decompression to the surface at the rate of 200 kPa/min (n=33). During the following 30 minutes, the rats walked in a 3 m/minute rotating cage and were monitored for signs of DCS. The control rats were pretreated with normobaric air (n=30), normoxic hyperbaric nitrox (250 kPa, 8.4% O2) (n=13), or N(G)-nitro-L-arginine methyl ester (L-NAME) 30 minutes before HBO2 exposure (n=13). Nitric oxide (NO) levels were recorded immediately and 18 hours after HBO2 exposure in the brain and spinal cord. The incidence of DCS in rats pretreated with HBO2 was 30.3%, which was significantly lower than those treated with normobaric air (63.3%) (p<0.05) or hyperbaric nitrox (61.5%) (p<0.05). The onset time of DCS of the rats pretreated with HBO2 was significantly delayed compared with those treated with air (p<0.05). L-NAME nullified the HBO2 preconditioning effect. HBO2 increased NO level in the rat brain and spinal cord right after exposure; this effect was inhibited by L-NAME. Taken together, HBO2 preconditioning reduced the incidence of DCS in rats, and NO was involved in the prophylactic effect.

Saturated Hydrogen Saline Protects the Lung Against Oxygen Toxicity

Exposure to high oxygen concentrations leads to acute lung injury, including lung tissue and alveolar edema formation, congestion, intra-alveolar hemorrhage, as well as endothelial and epithelial cell apoptosis or necrosis. Several studies have reported that molecular hydrogen is an efficient antioxidant by gaseous rapid diffusion into tissues and cells. Moreover, consumption of water with dissolved molecular hydrogen to a saturated level (hydrogen water) prevents stress-induced cognitive decline in mice and superoxide formation in mice. The purpose of the present study was to investigate the effect of saturated hydrogen saline on pulmonary injury-induced exposure to >98% oxygen at 2.5 ATA for five hours. Adult male Sprague-Dawley (SD) rats were randomly divided into three groups: control group, saline group and saturated hydrogen saline group. Hematoxylin and eosin (H&E) staining were used to examine histological changes. The lung wet to dry (W/D) weight ratio was calculated. The concentration of protein and total cell counts in bronchoalveolar lavage fluid (BALF) were measured. Lactate dehydrogenase (LDH) in serum and BALF were measured by spectrophotometer. The light microscope findings showed that saturated hydrogen saline reduced the impairment when compared with the saline group: Saturated hydrogen saline decreased lung edema, reduced LDH activity in BALF and serum, and decreased total cells and protein concentration in BALF. These results demonstrated that saturated hydrogen saline alleviated hyperoxia-induced pulmonary injury, which was partly responsible for the inhibition of oxidative damage.

The Cardiorenal Syndrome in Heart Failure: an Evolving Paradigm

Heart failure constitutes a significant source of morbidity and mortality in the United States, and its incidence and prevalence continue to grow, increasing its burden on the healthcare system. Renal dysfunction in patients with heart failure is common and has been associated with adverse clinical outcomes. This interaction, termed the cardiorenal syndrome, is a complex phenomenon characterized by a pathophysiologic disequilibrium between the heart and the kidney, in which malfunction of 1 organ consequently promotes the impairment of the other. Multiple neurohumoral mechanisms are involved in this cardiorenal interaction, including the deficiency of and/or resistance to compensatory natriuretic peptides, leading to sodium retention, volume overload and organ remodeling. Management of patients with the cardiorenal syndrome can be challenging and should be individualized. Emerging therapies must address the function of both organs to secure better clinical outcomes. To this end, a multidisciplinary approach is recommended to achieve optimal results.

Microfluidics for Positron Emission Tomography Probe Development

Owing to increased needs for positron emission tomography (PET), high demands for a wide variety of radiolabeled compounds will have to be met by exploiting novel radiochemistry and engineering technologies to improve the production and development of PET probes. The application of microfluidic reactors to perform radiosyntheses is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional labeling systems. Microfluidics-based radiochemistry can lead to the use of smaller quantities of precursors, accelerated reaction rates, and easier purification processes with greater yield and higher specific activity of desired probes. Several proof-of-principle examples along with the basics of device architecture and operation and the potential limitations of each design are discussed. Along with the concept of radioisotope distribution from centralized cyclotron facilities to individual imaging centers and laboratories ("decentralized model"), an easy-to-use, stand-alone, flexible, fully automated, radiochemical microfluidic platform can provide simpler and more cost-effective procedures for molecular imaging using PET.

A Rapid Pathway Toward a Superb Gene Delivery System: Programming Structural and Functional Diversity into a Supramolecular Nanoparticle Library

Nanoparticles are regarded as promising transfection reagents for effective and safe delivery of nucleic acids into a specific type of cells or tissues providing an alternative manipulation/therapy strategy to viral gene delivery. However, the current process of searching novel delivery materials is limited due to conventional low-throughput and time-consuming multistep synthetic approaches. Additionally, conventional approaches are frequently accompanied with unpredictability and continual optimization refinements, impeding flexible generation of material diversity creating a major obstacle to achieving high transfection performance. Here we have demonstrated a rapid developmental pathway toward highly efficient gene delivery systems by leveraging the powers of a supramolecular synthetic approach and a custom-designed digital microreactor. Using the digital microreactor, broad structural/functional diversity can be programmed into a library of DNA-encapsulated supramolecular nanoparticles (DNA⊂SNPs) by systematically altering the mixing ratios of molecular building blocks and a DNA plasmid. In vitro transfection studies with DNA⊂SNPs library identified the DNA⊂SNPs with the highest gene transfection efficiency, which can be attributed to cooperative effects of structures and surface chemistry of DNA⊂SNPs. We envision such a rapid developmental pathway can be adopted for generating nanoparticle-based vectors for delivery of a variety of loads.

Cucurbitacin D Induces Fetal Hemoglobin Synthesis in K562 Cells and Human Hematopoietic Progenitors Through Activation of P38 Pathway and Stabilization of the γ-globin MRNA

The search for novel therapeutic candidates targeting fetal hemoglobin (HbF) activation to reduce the imbalance of globin genes is regarded as a promising approach for the clinical management of sickle cell disease and β-thalassemia. For the first time, we identified cucurbitacin D (CuD), an oxygenated tetracyclic triterpenoid, as a molecular entity inducing γ-globin gene expression and HbF synthesis in K562 cells and human hematopoietic progenitors from a β-thalassemia patient. CuD demonstrated a higher potency in HbF induction when compared with hydroxyurea, which was revealed by the evidence that CuD results in a higher fetal cell percentage and greater HbF content in K562 cells, in addition, to being less cytotoxic. Moreover, CuD also promotes higher HbF expression in primary erythroid cells. In the study to elucidate the molecular mechanisms of CuD's action, our data indicated that CuD-stimulated HbF synthesis was mediated by p38 pathway activation. At the post-transcriptional level, CuD treatment led to a significant elongation of the γ-globin mRNA half-life in K562 cells. Taken together, the results suggest that CuD may be a potential therapeutic agent for β-hemoglobinopathies, including sickle cell anemia and β-thalassemia.

Microfluidic Device for Robust Generation of Two-component Liquid-in-air Slugs with Individually Controlled Composition

Using liquid slugs as microreactors and microvessels enable precise control over the conditions of their contents on short-time scales for a wide variety of applications. Particularly for screening applications, there is a need for control of slug parameters such as size and composition. We describe a new microfluidic approach for creating slugs in air, each comprising a size and composition that can be selected individually for each slug. Two-component slugs are formed by first metering the desired volume of each reagent, merging the two volumes into an end-to-end slug, and propelling the slug to induce mixing. Volume control is achieved by a novel mechanism: two closed chambers on the chip are initially filled with air, and a valve in each is briefly opened to admit one of the reagents. The pressure of each reagent can be individually selected and determines the amount of air compression, and thus the amount of liquid that is admitted into each chamber. We describe the theory of operation, characterize the slug generation chip, and demonstrate the creation of slugs of different compositions. The use of microvalves in this approach enables robust operation with different liquids, and also enables one to work with extremely small samples, even down to a few slug volumes. The latter is important for applications involving precious reagents such as optimizing the reaction conditions for radiolabeling biological molecules as tracers for positron emission tomography. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10404-010-0617-0) contains supplementary material, which is available to authorized users.

A Digital Microfluidic Droplet Generator Produces Self-assembled Supramolecular Nanoparticles for Targeted Cell Imaging

Controlling the size distribution of polymer-based nanoparticles is a challenging task due to their flexible core and surface structures. To accomplish such as task requires very precise control at the molecular level. Here we demonstrate a new approach whereby uniform-sized supramolecular nanoparticles (SNPs) can be reliably generated using a digital microfluidic droplet generator (DMDG) chip. A microfluidic environment enabled precise control over the processing parameters, and therefore high batch-to-batch reproducibility and robust production of SNPs with a very narrow size distribution could be realized. Digitally adjustment of the mixing ratios of the building blocks on the DMDG chip allowed us to rapidly scan a variety of synthesis conditions without consuming significant amounts of reagents. Nearly uniform SNPs with sizes ranging from 35 to 350 nm were obtained and characterized by transmission electron microscopy and dynamic light scattering. In addition, we could fine-tune the surface chemistry of the SNPs by incorporating an additional building block functionalized with specific ligands for targeting cells. The sizes and surface properties of these SNPs correlated strongly with their cell uptake efficiencies. This study showed a feasible method for microfluidic-assisted SNP production and provided a great means for preparing size-controlled SNPs with desired surface ligand coverage.

Discovery, Identification and Comparative Analysis of Non-specific Lipid Transfer Protein (nsLtp) Family in Solanaceae

Plant non-specific lipid transfer proteins (nsLtps) have been reported to be involved in plant defense activity against bacterial and fungal pathogens. In this study, we identified 135 (122 putative and 13 previously identified) Solanaceae nsLtps, which are clustered into 8 different groups. By comparing with Boutrot's nsLtp classification, we classified these eight groups into five types (I, II, IV, IX and X). We compared Solanaceae nsLtps with Arabi-dopsis and Gramineae nsLtps and found that (1) Types I, II and IV are shared by Solanaceae, Gramineae and Arabidopsis; (2) Types III, V, VI and VIII are shared by Gramineae and Arabidopsis but not detected in Solanaceae so far; (3) Type VII is only found in Gramineae whereas type IX is present only in Arabidopsis and Solanaceae; (4) Type X is a new type that accounts for 52.59% Solanaceae nsLtps in our data, and has not been reported in any other plant so far. We further built and compared the three-dimensional structures of the eight groups, and found that the major functional diversification within the nsLtp family could be predated to the monocot/dicot divergence, and many gene duplications and sequence variations had happened in the nsLtp family after the monocot/dicot divergence, especially in Solanaceae.

Emitting Far-field Multicolor Patterns and Characters Through Plastic Diffractive Micro-optics Elements Illuminated by Common Gaussian Lasers in the Visible Range

Far-field multicolor patterns and characters are emitted effectively in a relatively wide and deep spatial region by plastic diffractive micro-optics elements (DMOEs), which are illuminated directly by common Gaussian lasers in the visible range. Phase-only DMOEs are composed of a large number of fine step-shaped phase microstructures distributed sequentially over the plastic wafer selected. The initial DMOEs in silicon wafer are fabricated by an innovative technique with a combination of a single-mask ultraviolet photolithography and low-cost and rapid wet KOH etching. The fabricated silicon DMOEs are further converted into a nickel mask by the conventional electrochemical method, and they are finally transferred onto the surface of the plastic wafer through mature hot embossing. Morphological measurements show that the surface roughness of the plastic DMOEs is in the nanometer range, and the feature height of the phase steps in diffractive elements is in the submicrometer scale, which can be designed and adjusted flexibly according to requirements. The dimensions of the DMOEs can be changed from the order of millimeters to centimeters. A large number of pixel phase microstructures with a square microappearance employed to construct the phase-only DMOEs are created by the Gerchberg-Saxton algorithm, according to the target patterns and characters and common Gaussian lasers manipulated by the DMOEs fabricated.

Microfluidic-based 18F-labeling of Biomolecules for Immuno-positron Emission Tomography

Methods for tagging biomolecules with fluorine 18 as immuno-positron emission tomography (immunoPET) tracers require tedious optimization of radiolabeling conditions and can consume large amounts of scarce biomolecules. We describe an improved method using a digital microfluidic droplet generation (DMDG) chip, which provides computer-controlled metering and mixing of 18F tag, biomolecule, and buffer in defined ratios, allowing rapid scouting of reaction conditions in nanoliter volumes. The identified optimized conditions were then translated to bench-scale 18F labeling of a cancer-specific engineered antibody fragments, enabling microPET imaging of tumors in xenografted mice at 0.5 to 4 hours postinjection.

Hydrogen Therapy May Be a Novel and Effective Treatment for COPD

The protective effect of hydrogen (H(2)) on ROS-induced diseases has been proved by many researches, which demonstrated that through eliminating •OH and •ONOO-, H(2) could effectively attenuate lipid and DNA peroxidation, improve cellular antioxidant capacity, and then protect cells against oxidant damage. Most of free radicals in human body are ROS, including O(2)•-,•OH, H(2)O(2), NO•,•ONOO-, and so on. Under normal circumstances cells are able to maintain an adequate homeostasis between the formation and removal of ROS through particular enzymatic pathways or antioxidants. But under some pathological conditions, the balance is disturbed, leading to oxidative stress and various diseases, such as chronic obstructive pulmonary disease (COPD). Studies have shown that ROS played a pivotal role in the development of COPD and some antioxidants were effective in the protection against the damaging effects of oxidative stress. Therefore, we hypothesize that owing to its peculiarity to eliminate toxic ROS, hydrogen therapy may be a novel and effective treatment for COPD.

Protective Effect of Hydrogen-rich Saline on Decompression Sickness in Rats

Hydrogen (H2) has been reported to be effective in the treatment of oxidative injury, which plays an important role in the process of decompression sickness (DCS). This study was designed to test whether H2-rich saline (saline saturated with molecular hydrogen) protected rats against DCS.

Discrete Subaortic Stenosis in a Patient with a History of Repaired AV Canal Defect

Vascular Endothelial Dysfunction in Patients with Newly Diagnosed Type 2 Diabetes and Effects of 2-year and 5-year Multifactorial Intervention

Investigate short- and long-term effect of multifactorial intervention on endothelial dysfunction in patients with newly diagnosed type 2 diabetes.

Rapid Purification of Cell Encapsulated Hydrogel Beads from Oil Phase to Aqueous Phase in a Microfluidic Device

In this paper, we demonstrate a new type of microfluidic chip that can realize continuous-flow purification of hydrogel beads from a carrier oil into aqueous solution by using a laminar-like oil/water interface. The microfluidic chip is composed by two functional components: (1) a flow-focusing bead generation module that can control size and shape of beads, (2) a bead extraction module capable of purifying hydrogel beads from oil into aqueous solution. This module is featured with large branch channels on one side and small ones on the opposite side. Water is continuously infused into the bead extraction module through the large branch channels, resulting in a laminar-like oil/water interface between the branch junctions. Simulation and experimental data show that the efficiency of oil depletion is determined by the relative flow rates between infused water and carrier oil. By using such a microfluidic device, viable cells (HCT116, colon cancer cell line) can be encapsulated in the hydrogel beads and purified into a cell culture media. Significantly improved cell viability was achieved compared to that observed by conventional bead purification approaches. This facile microfluidic chip could be a promising candidate for sample treatment in lab-on-a-chip applications.

Combined Effects of Intravenous Perfluorocarbon Emulsion and Oxygen Breathing on Decompression-induced Spinal Cord Injury in Rats

The spinal cord is one of the most commonly affected sites in decompression sickness (DCS). Alternative methods have long been sought to protect against DCS spinal cord dysfunction, especially when hyperbaric treatment is unavailable. Use of perfluorocarbon (PFC) emulsion with or without oxygen breathing has shown survival benefits in DCS animal models. The effectiveness of intravenous PFC emulsion with oxygen breathing on spinal cord function was studied. Somatosensory-evoked potentials (SSEPs) and histologic examination were chosen to serve as measures. After fast decompression (203 kPa/minute) from 709 kPa (for 60 minutes), male Sprague-Dawley rats randomly received: 1) air and saline; 2) oxygen (O2) and saline; 3) O2 and PFC emulsion. The incidence and average number of abnormal SSEP waves in survival animals that received O2 and PFC emulsion were significantly reduced (P < 0.05). Foci of demyelination, necrosis and round non-staining defects in white matter regions of the spinal cord could be found in severe DCS rats. We concluded that administration of PFC emulsion combined with oxygen breathing was beneficial for DCS spinal conductive dysfunction in rats.

BIGpre: A Quality Assessment Package for Next-Generation Sequencing Data

The emergence of next-generation sequencing (NGS) technologies has significantly improved sequencing throughput and reduced costs. However, the short read length, duplicate reads and massive volume of data make the data processing much more difficult and complicated than the first-generation sequencing technology. Although there are some software packages developed to assess the data quality, those packages either are not easily available to users or require bioinformatics skills and computer resources. Moreover, almost all the quality assessment software currently available didn't taken into account the sequencing errors when dealing with the duplicate assessment in NGS data. Here, we present a new user-friendly quality assessment software package called BIGpre, which works for both Illumina and 454 platforms. BIGpre contains all the functions of other quality assessment software, such as the correlation between forward and reverse reads, read GC-content distribution, and base Ns quality. More importantly, BIGpre incorporates associated programs to detect and remove duplicate reads after taking sequencing errors into account and trimming low quality reads from raw data as well. BIGpre is primarily written in Perl and integrates graphical capability from the statistics package R. This package produces both tabular and graphical summaries of data quality for sequencing datasets from Illumina and 454 platforms. Processing hundreds of millions reads within minutes, this package provides immediate diagnostic information for user to manipulate sequencing data for downstream analyses. BIGpre is freely available at http://bigpre.sourceforge.net.

Obesity Hypertension: the Regulatory Role of Leptin

Leptin is a 16-kDa-peptide hormone that is primarily synthesized and secreted by adipose tissue. One of the major actions of this hormone is the control of energy balance by binding to receptors in the hypothalamus, leading to reduction in food intake and elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect mechanisms, may play an important role in cardiovascular and renal regulation. While the relevance of endogenous leptin needs further clarification, it appears to function as a pressure and volume-regulating factor under conditions of health. However, in abnormal situations characterized by chronic hyperleptinemia such as obesity, it may function pathophysiologically for the development of hypertension and possibly also for direct renal, vascular, and cardiac damage.

Switching Frequency Response Characteristics of a Low Cost Wireless Power Driving and Controlling System for Electrically Tunable Liquid Crystal Microlenses

The essential switching frequency response characteristics of a low cost wireless power driving and controlling system for electrically tunable liquid crystal microlenses (ETLCMs) are obtained. The wireless power system is mainly composed of two coils with different radius and winding as well as a power metal-oxide-semiconductor field effect transistor switch. The voltage response in the small coil, which is connected directly with ETLCMs, is measured and analyzed under the condition of changing some key parameters of the coil system, such as the width of switching frequency region and the duty-cycle of the switching signal ranging from 20% to 80% in intervals of 20%. Through extending the switching frequency range to a few hundreds of kilohertz, an attractive property of only modulating switching frequency to tune precisely the rms voltage in the small coil for ETLCMs is presented. Some interesting phenomena in high frequency regions, for instance, the rms voltage being stable or slightly changed as the frequency, the voltage response cutoff or disappearance after the frequency surpassing a threshold value, and then regeneration after lowering the frequency to lower frequency point than that of generating voltage response cutoff during increasing frequency, are also discovered.

β-receptor Antagonist Cessation Resulting in Tako-tsubo Cardiomyopathy in a Man with Quadriplegia

Consumption of Hydrogen Water Reduces Paraquat-induced Acute Lung Injury in Rats

Exposure to paraquat leads to acute lung injury and oxidative stress is widely accepted as a contributor to paraquat-induced acute lung injury. Recent studies have reported that consumption of water with dissolved molecular hydrogen to a saturated level (hydrogen water) prevents oxidative stress-induced diseases. Here, we investigated whether consumption of saturated hydrogen saline protects rats against paraquat-induced acute lung injury. Adult male Sprague-Dawley (SD) rats were randomly divided into four groups: Control group; hydrogen water-only group (HW group); paraquat-only group (PQ group); paraquat and hydrogen water group (PQ + HW group). The rats in control group and HW group drank pure water or hydrogen water; the rats in PQ group and PQ + HW group were intraperitonealy injected with paraquat (35 mg/kg) and then provided pure water or hydrogen water. Both biochemical and histological lung alterations were measured. The results showed that hydrogen water ameliorated these alterations, demonstrating that hydrogen water alleviated paraquat-induced acute lung injury possibly by inhibition of oxidative damage.

Highly Efficient Capture of Circulating Tumor Cells by Using Nanostructured Silicon Substrates with Integrated Chaotic Micromixers

The Kidney in Heart Failure: Friend or Foe?

Heart failure constitutes a significant source of morbidity and mortality in the United States and its incidence and prevalence continue to grow, increasing its burden on the health care system. Renal dysfunction in patients with heart failure is common and has been associated with adverse clinical outcomes. This complex interaction is characterized by a pathophysiological disequilibrium between the heart and the kidney, in which cardiac malfunction promotes renal impairment, which in turn feeds back for further deterioration of cardiovascular function. Multiple neurohumoral and hemodynamic mechanisms are involved in this cardiorenal dyshomeostasis, including the deficiency of and/or resistance to compensatory natriuretic peptides, leading to sodium retention, volume overload and organ remodeling. Management of patients with cardiorenal dysfunction can be challenging and should be individualized. Emerging therapies must address the impairment of both organs to secure better clinical outcomes. To this end, a multidisciplinary approach is warranted to achieve optimal results.

Fermentative Production of Ethanol from Syngas Using Novel Moderately Alkaliphilic Strains of Alkalibaculum Bacchi

Ethanol production from syngas using three moderately alkaliphilic strains of a novel genus and species Alkalibaculum bacchi CP11(T), CP13 and CP15 was investigated in 250 ml bottle fermentations containing 100ml of yeast extract medium at 37 °C and pH 8.0. Two commercial syngas mixtures (Syngas I: 20% CO, 15% CO(2), 5% H(2), 60% N(2)) and (Syngas II: 40% CO, 30% CO(2), 30% H(2)) were used. Syngas I and Syngas II represent gasified biomass and coal, respectively. The maximum ethanol concentration (1.7 g l(-1)) and yield from CO (76%) were obtained with strain CP15 and Syngas II after 360 h. CP15 produced over twofold more ethanol with Syngas I compared to strains CP11(T) and CP13. In addition, CP15 produced 18% and 71% more ethanol using Syngas II compared to strains CP11(T) and CP13, respectively. These results show that CP15 is the most promising for ethanol production because of its higher growth and ethanol production rates and yield compared to CP11(T) and CP13.

Angina Pectoris in a Patient with Protein C Deficiency and Deep Vein Thrombosis: Thrombus Versus Myxoma?

A 55-year-old Caucasian man with history of hypertension, diabetes mellitus, protein C deficiency, and deep vein thrombosis presented with typical angina. Both computed tomography and transesophageal echocardiography identified a mobile mass in left atrium but could not differentiate between thrombus and myxoma. A cardiac catheterization with coronary angiography demonstrated tumor neovascularization, suggestive of myxoma. Pathology examination after mass resection confirmed the diagnosis. Patients with myxoma could present with obstructive, embolic, or constitutional symptoms. However, typical angina has never been reported as the primary manifestation. Although being helpful, various noninvasive imaging modalities, including magnetic resonance image, often have limitations to help making a definitive diagnosis, before surgery decision, especially under hypercoagulable condition. In contrast, cardiac catheterization can help not only in differentiation diagnosis but also in detecting possible intracoronary embolization from myxoma. In patients with myxoma complicated with hypercoagulable disorders, anticoagulation will play essential role in long-term care. © 2011 Wiley Periodicals, Inc.

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