The capability of continuously sampling the extracellular fluid opens up a wide range of applications of microdialysis in biological, pharmaceutical, and clinical studies. Existing microdialysis, however, faces challenges in sampling analytes with fast clearance and limited diffusivity because sampling resolution is limited by device size. Size reduction in probes and interconnected cannulae is a promising solution to improve temporal and spatial resolution. But the back pressure produced by resistance to laminar flows will be magnified in smaller channels, raising a concern as to whether it is feasible to operate continuous perfusion for miniaturized microdialysis. We demonstrate that a 10-fold smaller channel will exhibit 100-fold larger back pressure in response to the increase in the flow rate to maintain the relative recovery. In order to overcome the foreseen back pressure issue, this paper discusses a new concept using discrete droplets instead of continuous flows to operate dialysis in a miniaturized probe. This conceptual design is referred to as droplet-based digital microdialysis, in which droplets are produced, controlled and advanced within microchannels at a rate that in theory should allow for analytes to equilibrate with the extracellular fluid under no flow conditions. Expecting that a digital droplet design will entirely eliminate back pressure by introducing air between droplets, we numerically compare the equilibration kinematics of droplets to that of continuous flow. Results suggest equilibration of low molecular weight analytes between intermittently stationary droplets and the extracellular fluid in a few seconds. Considerations in design, prototyping, calibration and quantification, and the integration with other devices are suggested.
Droplet; Microdialysis; Quantitative; Back pressure; Miniaturization
A hybrid sensor for monitoring volatile organic compounds (VOCs) in air is developed. The device combines two orthogonal sensing principles, selective molecular binding with a microfabricated quartz tuning fork detector and separation of analytes with a column. The tuning fork detector is functionalized with molecular imprinted polymers for selective binding to benzene, toluene, ethylbenzene, and xylenes (BTEX), and the separation column provides further discrimination of the analytes for real world complex sample analysis. The device is wireless, portable, battery-powered, and cell-phone operated, and it allows reliable detection in parts per billion (ppb) by volume-levels of BTEX in the presence of complex interferents. The hybrid device is suitable for occupational, environmental health, and epidemiological applications.
Air quality monitoring; environmental monitoring; chemical sensors; wireless sensors; environmental sensors; volatile organic compounds; VOCs
The aim of this study was to evaluate the combined contribution of 8 polymorphisms to the risk of Alzheimer's disease (AD).
Through a comprehensive literature search for genetic variants involved in the AD association study, we harvested a total of 6 genes (8 polymorphisms) for the current meta-analyses. These genes consisted of A2M (5bp I/D and V1000I), ABCA2 (rs908832), CHAT (1882G >A, 2384G >A), COMT (Val158Met), HTR6 (267C >T) and LPL (Ser447Ter).
A total of 33 studies among 9,453 cases and 10,833 controls were retrieved for the meta-analyses of 8 genetic variants. It was showed that A2M V1000I (odd ratio (OR) = 1.26, 95% confidence interval (CI) = 1.07–1.49, P = 0.007), rs908832 allele of ABCA2 (OR = 1.55, 95% CI = 1.12–2.16, P = 0.009), 2384G >A of CHAT (OR = 1.22, 95% CI = 1.00–1.49, P = 0.05) and Ser447Ter of LPL in the Northern-American population (OR = 0.56, 95% CI = 0.35–0.91, P = 0.02) were significantly associated with the risk of AD. No association was found between the rest of the 5 polymorphisms and the risk of AD.
Our results showed that A2M V1000I polymorphism in German, Korean, Chinese, Spanish, Italian and Polish populations, rs90883 of ABCA2 gene in French, American, Swiss, Greek and Japanese populations, 2384G >A of CHAT gene in British and Korean populations and LPL Ser447Ter in the Northern-American population were associated with the risk of AD.
Macrolide treatment failure in syphilis patients is associated with a single point mutation (either A2058G or A2059G) in both copies of the 23S rRNA gene in Treponema pallidum strains. The conventional method for the detection of both point mutations uses nested PCR combined with restriction enzyme digestions, which is laborious and time-consuming. We initially developed a TaqMan-based real-time duplex PCR assay for detection of the A2058G mutation, and upon discovery of the A2059G mutation, we modified the assay into a triplex format to simultaneously detect both mutations. The point mutations detected by the real-time triplex PCR were confirmed by pyrosequencing. A total of 129 specimens PCR positive for T. pallidum that were obtained from an azithromycin resistance surveillance study conducted in the United States were analyzed. Sixty-six (51.2%) of the 129 samples with the A2058G mutation were identified by both real-time PCR assays. Of the remaining 63 samples that were identified as having a macrolide-susceptible genotype by the duplex PCR assay, 17 (27%) were found to contain the A2059G mutation by the triplex PCR. The proportions of macrolide-susceptible versus -resistant genotypes harboring either the A2058G or the A2059G mutation among the T. pallidum strains were 35.6, 51.2, and 13.2%, respectively. None of the T. pallidum strains examined had both point mutations. The TaqMan-based real-time triplex PCR assay offers an alternative to conventional nested PCR and restriction fragment length polymorphism analyses for the rapid detection of both point mutations associated with macrolide resistance in T. pallidum.
The purpose of this study was to investigate in vivo three- dimensional tibiofemoral kinematics and femoral condylar motion in knees with anterior cruciate ligament (ACL) deficiency during a knee bend activity. Ten patients with unilateral ACL rupture were enrolled. Both the injured and contralateral normal knees were imaged using biplane radiography at extension and at 15°, 30°, 60°, 90°, and 120° of flexion. Bilateral knees were next scanned by computed tomography, from which bilateral three-dimensional knee models were created. The in vivo tibiofemoral motion at each flexion position was reproduced through image registration using the knee models and biplane radiographs. A joint coordinate system containing the geometric center axis of the femur was used to measure the tibiofemoral motion. In ACL deficiency, the lateral femoral condyle was located significantly more posteriorly at extension and at 15° (p < 0.05), whereas the medial condylar position was changed only slightly. This constituted greater posterior translation and external rotation of the femur relative to the tibia at extension and at 15° (p < 0.05). Furthermore, ACL deficiency led to a significantly reduced extent of posterior movement of the lateral condyle during flexion from 15° to 60° (p < 0.05). Coupled with an insignificant change in the motion of the medial condyle, the femur moved less posteriorly with reduced extent of external rotation during flexion from 15° to 60° in ACL deficiency (p < 0.05). The medial- lateral and proximal-distal translations of the medial and lateral condyles and the femoral adduction-abduction rotation were insignificantly changed after ACL deficiency. The results demonstrated that ACL deficiency primarily changed the anterior-posterior motion of the lateral condyle, producing not only posterior subluxation at low flexion positions but also reduced extent of posterior movement during flexion from 15° to 60°.
Three-dimensional tibiofemoral kinematics and femoral condylar motion in ACL-deficient knees during upright weight-bearing flexion were measured using biplane radiography with the geometric center axis.
ACL deficiency caused posterior subluxation of the lateral condyle with excess external femoral rotation at early flexion positions.
On flexion from 15° to 60°, the lateral condyle moved slightly posteriorly in ACL deficiency leading to reduced extent of external femoral rotation.
anterior cruciate ligament; injury; kinematics; tibiofemoral; femoral condyle; radiography
A wearable monitor that can reliably, accurately and continuously measure personal exposure levels of various toxicants would not only accelerate the current environmental and occupational health and safety studies, but also enable new studies that are not possible with the current monitoring technology. Developing such a monitor has been a difficult challenge, and requires innovative sensing science and creative engineering.
We have developed, built and tested a wearable monitor for real-time detection of toxic hydrocarbons and acids in environment. The monitor is low-cost, accurate, and user-friendly. In addition, it can communicate wirelessly with a cell phone in which the monitoring results can be processed, displayed, stored and transmitted to a designated computer. We have validated the functions and performance of the monitor, and carried out field tests with workers involving waste management, fire overhaul, and floor-cleaning activities, as well as with first- and second-hand smokers. The averaged exposure levels are in agreement with those determined by the standard NIOSH methods. The monitor provides accurate and real-time exposure assessment for the workers involving different activities. The real-time and continuous monitoring capability makes it possible to correlate the exposure levels with different activities and changes in the microenvironments. The monitor provides unprecedented real-time information that will help advance occupational safety and environmental health studies. It may also be used to better protect workers from occupational overexposure to toxic molecules.
environmental health; occupational health; exposure assessment; real-time monitor; toxicant monitor; wireless and wearable integrated sensor
The purpose of this study was to demonstrate the effectiveness of an integrin peptide ligand-labeled liposomal delivery system loaded with vascular endothelial growth factor (VEGF)-siRNA in a model study of gene therapy for retinopathy using human retinal pigment epithelial cells.
Arg(R)-Gly(G)-Asp(D) motif peptide conjugating polyethylene glycol modified (RGD-PEGylated) liposomes were prepared using a thin-film hydration method and optimized for surface charge, particle size, small interfering RNA (siRNA) load, and entrapment efficiency. Reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assays were used to determine VEGF levels in retinal pigment epithelial cells. Cytotoxicity was determined using the 3-[4, 5-dimethylthiazol-2-yl]-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and flow cytometry.
Physicochemical properties, including particle size, zeta potential, and siRNA load, of the prepared RGD-PEGylated liposomes and their entrapment efficiency were determined to be within the following ranges: 123.8–234.1 nm, 17.31–40.09 m V, 5.27%–6.33%, and >97%, respectively. RGD-PEGylated liposome-mediated fluorescent-labeled siRNA delivery demonstrated significantly enhanced cellular uptake, and 3 mol% RGD-PEGylated liposomes (having 3β-[N-(N’, N’-dimethylaminoethane) carbamoyl] cholesterol (DC-cholesterol) DSPE and DSPE-PEG(2000)-RGD with molar ratio of 50/47/3) were shown to have better efficacy with regard to specificity for retinal pigment epithelial cells, reduced cytotoxicity, and knockdown of the target molecule.
By integrin receptor-mediated endocytosis, 3 mol% RGD-PEGylated liposomes were shown to be a suitable vector when loaded with VEGF-siRNA for efficient downregulation of VEGF in retinal pigment epithelial cells at both the protein and gene levels. This integrin ligand-modified liposomal delivery system has therapeutic potential for ocular gene therapy.
vascular endothelial growth factor; siRNA delivery; liposome; retinal pigment epithelial cells
Suicide attempts constitute a serious clinical problem and have important implications for healthcare resources. The aim of the present study was to evaluate the effectiveness of case management using crisis postcards over a 6-month follow-up period.
A randomised controlled trial was conducted in Kaohsiung, Taiwan. Prevention of further suicide attempts was compared between two groups with and without the postcard intervention. The intervention group consisted of 373 participants (139 males, 234 females; age: 39.8 ± 14.0 yrs.). The control group consisted of 388 participants (113 males, 275 females; age: 40.0 ± 16.0 yrs.). A survival analysis was used to test the effectiveness of the crisis postcard intervention for the prevention of suicide reattempts. Per-protocol and intention-to-treat analyses were conducted.
The intention-to-treat analysis indicated that the crisis postcard had no effect (hazard ratio = 0.84; 95% CI = 0.56 – 1.29), whereas the per-protocol analysis showed a strong benefit for the crisis postcard (hazard ratio = 0.39; 95% CI = 0.21 – 0.72).
Although the results of the present study indicated that the postcard intervention did not reduce subsequent suicide behaviour, our study provides an alteration to the postcard intervention. Further studies need to be conducted to clarify whether this type of intervention can reduce subsequent suicidal behaviour, with a particular focus on reducing the rate of loss to follow-up.
Suicide re-attempts; Case management; Crisis postcard
To improve our understanding of indoor and outdoor personal exposures to common environmental toxicants released into the environment, new technologies that can monitor and quantify the toxicants anytime anywhere are needed. This paper presents a wearable sensor to provide such capabilities. The sensor can communicate with a common smart phone and provides accurate measurement of volatile organic compound concentration at a personal level in real time, providing environmental toxicants data every three minutes. The sensor has high specificity and sensitivity to aromatic, alkyl, and chlorinated hydrocarbons with a resolution as low as 4 parts per billion (ppb), with a detection range of 4 ppb to 1000 ppm (parts per million). The sensor's performance was validated using Gas Chromatography and Selected Ion Flow Tube - Mass Spectrometry reference methods in a variety of environments and activities with overall accuracy higher than 81% (r2 > 0.9). Field tests examined personal exposure in various scenarios including: indoor and outdoor environments, traffic exposure in different cities which vary from 0 to 50 ppmC (part-per-million carbon from hydrocarbons), and pollutants near the 2010 Deepwater Horizon's oil spill. These field tests not only validated the performance but also demonstrated unprecedented high temporal and spatial toxicant information provided by the new technology.
air monitoring; environmental health; indoor air quality; real-time sensor; personal exposure assessment; wireless and wearable integrated sensor
Bilateral internal mammary artery (BIMA) grafting in coronary artery surgery provides better long term outcomes than single internal mammary artery and saphenous vein grafting but the optimum configuration of BIMAs has not been established. This study analyzed perioperative and late outcomes of patients who underwent BIMA grafting with a composite Y configuration.
Patients (n=922) who underwent BIMA Y grafting were identified from a cardiac surgical database and then cross matched against hospital and cardiology databases and the state death register to identify episodes of repeat coronary angiography, cardiac surgical re-intervention and death. Analysis of repeat angiography was performed after retrieval of the angiogram reports.
In 95% of patients, full myocardial revascularization was achieved with BIMAs alone, using a composite Y configuration with an average of 4.1 IMA to coronary artery anastomoses per patient. The perioperative mortality was 1.5% and the 5-, 10- and 15-year survival estimates were 95%, 87% and 77% respectively. Analysis of 166 symptom-driven post-discharge coronary angiograms showed grafts to the left anterior descending artery and increasing severity of coronary artery stenosis at preoperative angiography as predictors of anastomotic patency.
Full myocardial revascularization can be achieved with reasonable safety in most patients with triple vessel disease and good left ventricular function, and provides good late survival.
Coronary artery bypass; internal mammary artery (IMA); myocardial revascularization
Thyroid hormones (THs) are potent mediators of several physiological processes, including embryonic development, cellular differentiation, metabolism, and cell growth. Triiodothyronine (T3) is the most biologically active TH form. Thyroid hormone receptors (TRs) belong to the nuclear receptor superfamily and mediate the biological functions of T3 via transcriptional regulation. TRs generally form heterodimers with the retinoid X receptor (RXR) and regulate target genes upon T3 stimulation. Research over the past few decades has revealed that disruption of cellular TH signaling triggers chronic liver diseases, including alcoholic or nonalcoholic fatty liver disease and hepatocellular carcinoma (HCC). Animal model experiments and epidemiologic studies to date imply close associations between high TH levels and prevention of liver disease. Moreover, several investigations spanning four decades have reported the therapeutic potential of T3 analogs in lowering lipids, preventing chronic liver disease, and as anticancer agents. Thus, elucidating downstream genes/signaling pathways and molecular mechanisms of TH actions is critical for the treatment of significant public health issues. Here, we have reviewed recent studies focusing on the roles of THs and TRs in several disorders, in particular, liver diseases. We also discuss the potential therapeutic applications of THs and underlying molecular mechanisms.
We have developed a suite of protein redesign algorithms that improves realistic in silico modeling of proteins. These algorithms are based on three characteristics that make them unique: (1) improved flexibility of the protein backbone, protein side chains, and ligand to accurately capture the conformational changes that are induced by mutations to the protein sequence; (2) modeling of proteins and ligands as ensembles of low-energy structures to better approximate binding affinity; and (3) a globally-optimal protein design search, guaranteeing that the computational predictions are optimal with respect to the input model. Here, we illustrate the importance of these three characteristics. We then describe OSPREY, a protein redesign suite that implements our protein design algorithms. OSPREY has been used prospectively, with experimental validation, in several biomedically-relevant settings. We show in detail how OSPREY has been used to predict resistance mutations and explain why improved flexibility, ensembles, and provability are essential for this application.
protein design; OSPREY; Dead-end elimination; protein ensembles; protein flexibility; K*; minDEE
Aims. The aim of this study is to compare our results of preoperative chemotherapy followed by pancreaticoduodenectomy (PD) with those of surgery alone in patients with localized resectable pancreatic ductal adenocarcinoma (PDAC). Methods. Outcome data for 112 patients of resectable PDAC who received preoperative chemoradiotherapy followed by PD (group I) between January 2004 and April 2010 were retrospectively analyzed and were compared with selected 120 patients who underwent PD alone (group II) in the same period. Results. Patients in group I had an incidence of locoregional recurrence of 17.1% compared to 30.8% in group II (P = 0.03). There were no statistically significant differences in postoperative morbidity (27.7% versus 30.8%) and mortality (2.67% versus 3.33%). The 1-, 2-, and 3-year survival rates were estimated at 82.1%, 54%, and 28%, respectively, with NCRT and 65.8%, 29.1%, and 10% without (P = 0.006). Nevertheless, preoperative chemotherapy did not reduce the 1-, 3-, and 5-year disease-free survival rates, which were estimated at 58%, 36.6%, and 12.5% with NCRT and 51.7%, 18.3%, and 7.5% without (P = 0.058). Conclusions. The treatment of NCRT followed by PD in patients with PDAC has a significantly lower rate of locoregional recurrence and a longer overall survival than those with surgery alone.
Comparison of major histocompatibility complex (MHC) genes across vertebrate species can reveal molecular mechanisms underlying the evolution of adaptive immunity-related proteins. As the first terrestrial tetrapods, amphibians deserve special attention because of their exposure to probably increased spectrum of microorganisms compared with ancestral aquatic fishes. Knowledge regarding the evolutionary patterns and mechanisms associated with amphibian MHC genes remains limited. The goal of the present study was to isolate MHC class I genes from two Rhacophoridae species (Rhacophorus omeimontis and Polypedates megacephalus) and examine their evolution.
We identified 27 MHC class I alleles spanning the region from exon 2 to 4 in 38 tree frogs. The available evidence suggests that these 27 sequences all belong to classical MHC class I (MHC Ia) genes. Although several anuran species only display one MHC class Ia locus, at least two or three loci were observed in P. megacephalus and R. omeimontis, indicating that the number of MHC class Ia loci varies among anuran species. Recombination events, which mainly involve the entire exons, played an important role in shaping the genetic diversity of the 27 MHC class Ia alleles. In addition, signals of positive selection were found in Rhacophoridae MHC class Ia genes. Amino acid sites strongly suggested by program to be under positive selection basically accorded with the putative antigen binding sites deduced from crystal structure of human HLA. Phylogenetic relationships among MHC class I alleles revealed the presence of trans-species polymorphisms.
In the two Rhacophoridae species (1) there are two or three MHC class Ia loci; (2) recombination mainly occurs between the entire exons of MHC class Ia genes; (3) balancing selection, gene duplication and recombination all contribute to the diversity of MHC class Ia genes. These findings broaden our knowledge on the evolution of amphibian MHC systems.
Major histocompatibility complex; Evolution; Rhacophorus omeimontis; Polypedates megacephalus
Recent advances in the treatment of cerebral gliomas have increased the demands on noninvasive neuroimaging for the diagnosis, therapeutic planning, tumor monitoring, and patient outcome prediction. In the meantime, improved magnetic resonance (MR) imaging techniques have shown much potentials in evaluating the key pathological features of the gliomas, including cellularity, invasiveness, mitotic activity, angiogenesis, and necrosis, hence, further shedding light on glioma grading before treatment. In this paper, an update of advanced MR imaging techniques is reviewed, and their potential roles as biomarkers of tumor grading are discussed.
VPg uridylylation is essential for picornavirus RNA replication. The VPg uridylylation reaction consists of the binding of VPg to 3D polymerase (3Dpol) and the transfer of UMP by 3Dpol to the hydroxyl group of the third amino acid Tyr of VPg. Previous studies suggested that different picornaviruses employ distinct mechanisms during VPg binding and uridylylation. Here, we report a novel site (Site-311, located at the base of the palm domain of EV71 3Dpol) that is essential for EV71 VPg uridylylation as well as viral replication. Ala substitution of amino acids (T313, F314, and I317) at Site-311 reduced the VPg uridylylation activity of 3Dpol by >90%. None of the Site-311 mutations affected the RNA elongation activity of 3Dpol, which indicates that Site-311 does not directly participate in RNA polymerization. However, mutations that abrogated VPg uridylylation significantly reduced the VPg binding ability of 3Dpol, which suggests that Site-311 is a potential VPg binding site on enterovirus 71 (EV71) 3Dpol. Mutation of a polymerase active site in 3Dpol and Site-311 in 3Dpol remarkably enables trans complementation to restore VPg uridylylation. In contrast, two distinct Site-311 mutants do not cause trans complementation in vitro. These results indicate that Site-311 is a VPg binding site that stabilizes the VPg molecule during the VPg uridylylation process and suggest a two-molecule model for 3Dpol during EV71 VPg uridylylation, such that one 3Dpol presents the hydroxyl group of Tyr3 of VPg to the polymerase active site of another 3Dpol, which in turn catalyzes VPg→VPg-pU conversion. For genome-length RNA, the Site-311 mutations that reduced VPg uridylylation were lethal for EV71 replication, which indicates that Site-311 is a potential antiviral target.
Nuclear factor kappa-B (NF-κB) signalling plays an important role in diabetic nephropathy. Altered expression of connexin43 (Cx43) has been found in kidneys of diabetic animals. The aim of the current study was to investigate the role of Cx43 in the activation of NF-κB induced by high glucose in glomerular mesangial cells (GMCs) and to determine whether c-Src is involved in this process.
We found that downregulation of Cx43 expression induced by high glucose activated NF-κB in GMCs. Orverexpression of Cx43 attenuated NF-κB p65 nuclear translocation induced by high glucose. High glucose inhibited the interaction between Cx43 and c-Src, and enhanced the interaction between c-Src and IκB-α. PP2, a c-Src inhibitor, also inhibited the tyrosine phosphorylation of IκB-α and NF-κB p65 nuclear translocation induced by high glucose. Furthermore, overexpression of Cx43 or inhibition of c-Src attenuated the upregulation of intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-beta 1 (TGF-β1) and fibronectin (FN) expression induced by high glucose.
In conclusion, downregulation of Cx43 in GMCs induced by high glucose activates c-Src, which in turn promotes interaction between c-Src and IκB-α and contributes to NF-κB activation in GMCs, leading to renal inflammation.
Connexin43; NF-κB signalling; c-Src; Diabetic nephropathy; Inflammation; Fibronectin
Chronic obstructive pulmonary disease (COPD) is an independent risk factor for cardiovascular morbidity and mortality. The aim of this study was to determine the prevalence of asymptomatic peripheral arterial disease (PAD) and the associated risk factors for patients with COPD.
This prospective cross-sectional study enrolled 427 COPD patients (mean age: 70.0 years) without PAD symptoms consecutively. Demographic data, lung function and cardiovascular risk factors were recorded. The ankle-brachial index (ABI) was used to detect PAD (ABI<0.90).
The overall prevalence of asymptomatic PAD in the COPD patients was 8% (2.5% in the younger participants (<65 years of age, n = 118) and 10% in the elderly participants (≥65 years of age, n = 309). The COPD patients with asymptomatic PAD had a significantly higher rate of hyperlipidemia (47.1% vs. 10.4%) and hypertension (79.4% vs. 45.8%) than those without asymptomatic PAD (p<0.05). There was no significant difference in lung function (forced vital capacity and forced expiratory volume in one second) between the two groups. In multivariate logistic regression, hyperlipidemia was the strongest independent factor for PAD (odds ratio (OR): 6.89, p<0.005), followed by old age (OR: 4.80), hypertension (OR: 3.39) and smoking burden (pack-years, OR: 1.02).
The prevalence of asymptomatic PAD among COPD patients in Taiwan is lower than in Western countries. Hyperlipidemia, old age, hypertension, and smoking burden were the associated cardiovascular risk factors. However, there was no association between lung function and PAD in the COPD patients.
Hyperhomocysteinemia (HHcy) is a risk factor for cognitive impairment. The purpose of this study was to determine the temporal pattern of cerebral pathology in a mouse model of mild HHcy, because understanding this time course provides the basis for understanding the mechanisms involved. C57Bl/6 mice with heterozygous deletion cystathionine β-synthase (cbs+/−; Het) were used as a model of mild HHcy along with their wild-type littermates (cbs+/+; WT). Mice were ‘young’ (5.3±0.2 months of age) and ‘old’ (16.6±0.9 months of age). Blood-brain barrier (BBB) permeability was quantified from Evans blue and sodium fluorescein extravasation. Microvascular architecture was assessed by z-stack confocal microscopy. Leukoaraiosis was measured from Luxol fast blue stained slides of paraffin brain sections. Inflammation was quantified using standard antibody-based immunohistochemical techniques. Cognitive function was assessed using the Morris water maze. BBB permeability was significantly greater in Het vs. WT mice at all ages (p<0.05). There were no differences in microvascular architecture among the groups. Compared with all other groups, old Het mice had significantly greater leukoaraiosis, inflammation in the fornix, and cognitive impairment (p<0.05). In mild HHcy, increased permeability of the BBB precedes the onset of cerebral pathology. This new paradigm may play a role in the progression of disease in HHcy.
The aims of this study were to evaluate the antioxidant activity and to identify the antioxidant components of a traditional Chinese medicine formula consisting of a combination of Shanzha (the fruit of Crataegus pinnatifida Bge. var. major N.E.Br., SZ) and Danshen (the root of Salvia miltiorrhiza Bge., DS). This medicine is extensively used to treat cardiovascular disease.
Twelve samples extracted and fractionated from SZ, DS and the formula (SZ+DS) were analyzed. The concentrations of eight phenolic compounds were determined by high performance liquid chromatography. Oxygen radical absorbance capacity (ORAC) assay and 1,1-diphenyl-2-picrylhydrazyl assay were conducted to explore the antioxidant activities of the samples and of the 15 phenolic compounds detected. Correlation analysis of the antioxidant activity of herb samples and their phenolic components was performed.
The main phenolic component in all SZ+DS samples was salvianolic acid B, which exhibited strong antioxidant activity (ORAC value: 16.73 ± 2.53, IC50 value: 8.80 ± 0.06 μM) compared with the other phenolic compounds. For all samples, there was a positive relationship between their total phenolic components and their antioxidant activities.
Phenolic compounds were the bioactive components of the herb samples, and salvianolic acid B was identified as the main bioactive compound in the SZ+DS formula.
Traditional Chinese medicine; Crataegus pinnatifida; Salvia miltiorrhiza; Antioxidant activity; Antioxidant compounds; HPLC; Oxygen radical absorbance capacity; DPPH assay
Hyperhomocysteinemia (HHcy) disrupts nitric oxide (NO) signaling and increases nitrative stress in cerebral microvascular endothelial cells (CMVECs). This is mediated, in part, by protein nitrotyrosinylation (3-nitrotyrosine; 3-NT) though the mechanisms by which extracellular homocysteine (Hcy) generates intracellular 3-NT are unknown. Using a murine model of mild HHcy (cbs+/− mouse), we show that 3-NT is significantly elevated in cerebral microvessels with concomitant reductions in serum NO bioavailability as compared with wild-type littermate controls (cbs+/+). Directed pharmacology identified a receptor-dependent mechanism for 3-NT formation in CMVECs. Homocysteine increased expression of inducible NO synthase (iNOS) and formation of 3-NT, both of which were blocked by inhibition of metabotropic glutamate receptor-5 (mGluR5) with the specific antagonist 2-methyl-6-(phenylethynyl) pyridine hydrochloride. Activation of mGluR5 is both sufficient and necessary to drive the nitrative stress because direct activation using the mGluR5-specific agonist (RS)-2-chloro-5-hydroxyphenylglycine also increased iNOS expression and 3-NT formation while knockdown of mGluR5 receptor expression by short hairpin RNA (shRNA) blocked their increase in response to Hcy. Nitric oxide derived from iNOS was required for Hcy-mediated formation of 3-NT because the effect was blocked by 1400W. These results provide the first evidence for a receptor-dependent process that explains how plasma Hcy levels control intracellular nitrative stress in cerebral microvascular endothelium.
blood–brain barrier; homocysteine; microvascular; oxidative stress; peroxynitrite
A technique suitable for diffusion tensor imaging (DTI) at high field strengths is presented in this work. The method is based on a periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) k-space trajectory using EPI as the signal readout module, and hence is dubbed PROPELLER EPI. The implementation of PROPELLER EPI included a series of correction schemes to reduce possible errors associated with the intrinsically higher sensitivity of EPI to off-resonance effects. Experimental results on a 3.0 Tesla MR system showed that the PROPELLER EPI images exhibit substantially reduced geometric distortions compared with single-shot EPI, at a much lower RF specific absorption rate (SAR) than the original version of the PROPELLER fast spin-echo (FSE) technique. For DTI, the self-navigated phase-correction capability of the PROPELLER EPI sequence was shown to be effective for in vivo imaging. A higher signal-to-noise ratio (SNR) compared to single-shot EPI at an identical total scan time was achieved, which is advantageous for routine DTI applications in clinical practice.
PROPELLER imaging; EPI; geometric distortions; specific absorption rate; diffusion tensor imaging
Cs0.33WO3 nanoparticles have been prepared successfully by a stirred bead milling process. By grinding micro-sized coarse powder with grinding beads of 50 μm in diameter, the mean hydrodynamic diameter of Cs0.33WO3 powder could be reduced to about 50 nm in 3 h, and a stable aqueous dispersion could be obtained at pH 8 via electrostatic repulsion mechanism. After grinding, the resulting Cs0.33WO3 nanoparticles retained the hexagonal structure and had no significant contaminants from grinding beads. Furthermore, they exhibited a strong characteristic absorption and an excellent photothermal conversion property in the near-infrared (NIR) region, owing to the free electrons or polarons. Also, the NIR absorption and photothermal conversion property became more significant with decreasing particle size or increasing particle concentration. When the concentration of Cs0.33WO3 nanoparticles was 0.08 wt.%, the solution temperature had a significant increase of above 30°C in 10 min under NIR irradiation (808 nm, 2.47 W/cm2). In addition, they had a photothermal conversion efficiency of about 73% and possessed excellent photothermal stability. Such an effective NIR absorption and photothermal conversion nanomaterial not only was useful in the NIR shielding, but also might find great potential in biomedical application.
Cesium tungsten oxide; Nanoparticles; Near infrared; Photothermal conversion; Bead milling
Social anxiety was compared between online and real-life interaction in a sample of 2,348 college students. Severity of social anxiety in both real-life and online interaction was tested for associations with depression, Internet addiction, Internet activity type (gaming versus chatting), and scores on Behavioral Inhibition System (BIS)/Behavioral Activation System (BAS) scales. The results showed that social anxiety was lower when interacting online than when interacting offline. Depression, Internet addiction, and high BIS and BAS scores were associated with high social anxiety. The social anxiety decreased more in online interaction among subjects with high social anxiety, depression, BIS, and BAS. This result suggests that the Internet has good potential as an alternative medium for delivering interventions for social anxiety. Further, the effect of BIS on social anxiety is decreased in online interaction. More attention should be paid for BIS when the treatment for social anxiety is delivered online.