Fabrication of gold nanoparticle-polymer composite particles with raspberry, core-shell and amorphous morphologies at room temperature via electrostatic interactions and diffusion.

Composite particles with varying morphologies composed of gold nanoparticles (Au NPs) and polymers were fabricated based on a combination of electrostatic interactions between the polymer particles and Au NPs and diffusion processes. The positively charged polymer particles were prepared from amino-terminated polystyrene (PS-NH2) and amino-terminated 1,2-polybutadiene (PB-NH2). Adsorption of citrate-stabilized Au NPs resulted in three different distribution states of Au NPs in the polymer particles, depending on the glass transition temperature (Tg) and molecular weight of the polymer. The adsorption of Au NPs onto PS-NH2 particles produced raspberry-like composite particle morphologies, while the NPs instead diffused into the PB-NH2 particles, since the Tg of PB-NH2 is below room temperature. The diffusion of Au NPs could be controlled by varying the molecular weight of the PB-NH2 and the diameter of the NPs, and both core-shell and amorphous distributions were successfully achieved.

New methodological approach to improve reproducibility of brachial artery flow-mediated dilatation.

BACKGROUND: Measurement of flow-mediated dilation (FMD) is well known as a noninvasive method for an assessment of vascular endothelial function. However, the reproducibility is a major issue of FMD measurement. The purpose of this study is to examine the reproducibility of the new FMD measurement with medial epicondyle method. METHODS: First, to evaluate the variability of the brachial artery diameter, 23 volunteers recruited from 32 healthy volunteers were examined for a brachial artery diameter at rest using with FMD equipment. Second, to evaluate the reproducibility of the FMD measurement, all volunteers underwent the FMD measurement, which was repeated at 2-week interval using the traditional method and the medial epicondyle method. The reproducibility in both methods was evaluated by 2 independent observers who measured on the same subject to assess the inter-observer reproducibility, and 1 observer who measured the same subject twice to assess the intra-observer reproducibility regarding the baseline value of arterial diameter and FMD. RESULTS: The variability of brachial artery diameter was 0.57 ± 0.27 mm in 23 healthy volunteers. In the study of inter- and intra-observer reproducibility, 2 parameters including intra-class correlation coefficient and Pearson's correlation coefficient by medial epicondyle method are superior to those by traditional method. CONCLUSIONS: These results suggest that medial epicondyle methodological approach to measure FMD is superior to traditional method.

Polymer Janus particles containing block-copolymer stabilized magnetic nanoparticles.

In this report, we show a simple route to fabricate Janus particles having magnetic nanoparticles inside them, which can respond and rotate along to magnetic fields. By solvent evaporation from the tetrahydrofran solution of polymer stabilized γ-Fe2O3 nanoparticles, polystyrene (PS), and polyisoprene containing water, aqueous dispersion of Janus microparticles were successfully prepared, and the γ-Fe2O3 nanoparticles were selectively introduced into the PS phase. We demonstrate rotation and accumulation of Janus particles by using a neodymium magnet.

Usefulness of high-concentration calcium chloride solution for correction of activated partial thromboplastin time (APTT) in patients with high-hematocrit value.

INTRODUCTION: Pseudoprolongation of activated partial thromboplastin time (APTT) is a serious problem in anticoagulation therapy for patients with high hematocrit, such as cyanotic congenital heart diseases. APTT pseudoprolongation occurs when APTT assay is performed using routinely used vacuum sampling tubes containing citrate. Because the plasma fraction is small in high-hematocrit blood, the prescribed volume of citrate would be excessive for APTT assay, resulting in prolongation of clotting or APTT pseudoprolongation. CLSI--The Clinical and Laboratory Standards Institute (formerly NCCLS) method is the established method to correct the pseudoprolongation. However, the CLSI method needs repeated blood drawings and time-consuming, complicate procedures. Thus, alternative simple method is desired. METHOD: We examined whether APTT pseudoprolongation would be prevented by the increase in free calcium ion concentration by using high-concentration calcium chloride solution for the assay. Blood samples were obtained from 15 patients with high hematocrit (65+/-6%) who had cyanotic congenital heart disease. RESULT: Conventional APTT assay using 0.025 mol/L calcium chloride solution gave greater APTT compared with the CLSI method (51.7+/-11.8 vs. 34.6+/-4.7 s, p<0.001). However, when 0.035 mol/L calcium chloride solution was used, APTT (36.6+/-5.8 s) was similar to that obtained from the CLSI method. There was a good correlation in APTT values between high-calcium chloride solution method and the CLSI method (the slope=0.57, r2=0.49). CONCLUSION: High-calcium chloride solution method is useful to correct APTT pseudoprolongation. Because of the simplicity and the need of a single blood drawing, this method would reduce the burdens of not only patients but also clinical laboratory.

Characteristic features of QRST integral mapping in patients with high risk Brugada syndrome.

BACKGROUND: The characteristic features of QRST integral mapping in the Brugada-type resting ECG of patients at a high risk for life-threatening ventricular arrhythmias were examined. METHODS AND RESULTS: QRST integral mapping was performed in 11 Brugada-type ECG patients with histories of aborted sudden death, spontaneous ventricular tachycardia and fibrillation (VT/VF) or programmed electric stimulation-inducible VT/VF (high risk group); 13 Brugada-type ECG patients without a history of such events (low risk group); and 21 age-matched healthy controls. Individual QRST isointegral maps revealed the minimum integral in the mid-to-right upper chest in 100% and 85% of the control and low risk groups, respectively, whereas this integral was 64% in the upper right back of the high risk group (p<0.05). On the QRST integral departure maps, the abnormal positive departure area (integral value>or=+2 standard deviation) was located in the mid-to-right upper chest in 82% and 8% of the high and low risk groups, respectively (p<0.05). During the follow-up period, sudden death or VF occurred in 4 of 6 high risk patients with both the abnormal findings. CONCLUSION: The abnormal positive departure area in the mid-to-right upper chest and the minimum QRST integral in the right upper back were distinct hallmarks for screening patients with the high risk Brugada-type ECG.