Surface Characterization, Antimicrobial Activity of Nonthermal Atmospheric-Pressure Plasma Jet on Polyvinyl Siloxane Impression Materials.

Background and Objectives The antimicrobial efficacy of a nonthermal atmospheric-pressure plasma jet (NAPPJ) on dental impression materials was investigated. Materials and Methods Type 3 polyvinyl siloxane was used as the impression material, and air and nitrogen NAPPJ were applied. The antibacterial effect of the NAPPJ was measured using the number of colony-forming units (CFUs) and scanning electron microscopy (SEM) images of Streptococcus mutans. Surface chemical characteristics of the impression material were examined using X-ray photoelectron spectroscopy (XPS) and contact angle measurement. Additionally, physical properties were analyzed through surface roughness measurement, detail reproduction, and strain-in-compression test. Results Compared with the control group, the plasma treatment group showed ruptured bacteria membranes, destroyed bacteria structures, a significant reduction in the number of CFUs, and a significantly reduced contact angle. Further, XPS analysis showed that their surface was significantly richer in hydroxyl groups. The surface roughness, detail reproduction, and strain-in-compression results indicated no significant differences between the plasma treatment and control groups. NAPPJ treatment could remove bacteria from polyvinyl siloxane dental impression materials without changing the surface's physical properties. Conclusion Therefore, it is considered a promising method for disinfection.

Preparation of a multi-modal agent for sentinel lymph node mapping using Evans blue and 99mTc-labeled mannosylated human serum albumin conjugate.

INTRODUCTION: The identification of sentinel lymph nodes (SLNs) is important in deciding the resection range during surgery. 99mTc-labeled mannosylated human serum albumin ([99mTc]Tc-MSA) is a radiopharmaceutical developed for SLN detection by targeting macrophages. Evans blue (EB) is a blue dye binding strongly to albumin and has been used for SLN detection. [99mTc]Tc-MSA-EB conjugate was prepared as a multi-modal imaging agent and tested its performance by visual investigation, fluorescence imaging and SPECT/CT for SLN mapping in mice. METHODS: EB was mixed with various concentration of MSA to prepare MSA-EB conjugates. The binding efficiencies were determined using thin-layer chromatography. The UV-VIS spectra and molar extinction coefficient of the conjugate were obtained. The fluorescence was monitored at the excitation wavelength range 420-780 nm and the emission wavelength range 520-845 nm. The [99mTc]Tc-MSA-EB conjugate and EB were injected into the footpads of normal BALB/c mice to check the lymph node (LN) uptakes. The visible, fluorescence, and SPECT/CT images were obtained after injection. RESULTS: The conjugation of EB with MSA increased by time and was saturated within 10 min. The molar extinction coefficient of the conjugate was 99,259.3/M/cm at 620 nm. The uptake of conjugate into the popliteal LN after injection into the footpads of mice was investigated visually and fluorescence imaging. SPECT/CT images showed that the standardized uptake values of [99mTc]Tc-MSA-EB conjugate in popliteal LN were about 4 times higher than in sciatic LN at all timepoints. It was confirmed by investigating resected LN that the blue color, fluorescence, and radioactivity of the [99mTc]Tc-MSA-EB conjugate were retained only on the LN and did not spread to adjoining tissues. CONCLUSION: [99mTc]Tc-MSA-EB conjugate has a great potential as a multi-modal SLN mapping agent which could be detected by visual investigation, fluorescence imaging, and SPECT/CT.

Comparison of endothelial function improvement estimated with reactive hyperemia index between ramipril and telmisartan in hypertensive patients.

BACKGROUND: Endothelium has a function to regulate vascular tone by releasing mediators either vasodilating or vasoconstricting blood vessels. Endothelial dysfunction can be measured conveniently by Reactive Hyperemia Index (RHI) with a peripheral arterial tonometry. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II (AT II) receptor blockers (ARBs) are considered to have beneficial effects on endothelium through inhibition of AT II. This study was performed to compare the effect of ACEIs or ARBs on endothelial function estimated by RHI in hypertensive patients. METHODS: Twenty consecutive patients with hypertension (57.9 ± 11.3 years, 60% men) were assigned to receive treatment with ramipril or telmisartan for eight weeks (n = 10 per group). Blood pressure (BP) and RHI were measured at baseline and after eight weeks treatment. RESULTS: The two groups were similar in terms of demographic and laboratory characteristics. But baseline systolic BP and pulse pressure (PP) were higher in telmisartan group than ramipril group (systolic BP, 159 ± 6.83 vs 150 ± 7.49, p = 0.028; PP, 75.0 ± 14.0 vs 60.3 ± 12.4, p = 0.034). In both groups, systolic and diastolic BP decreased significantly after eight weeks treatment (p < 0.05 for each). Although PP reduced in both group (ramipril group, 60.3 ± 12.4 mm Hg to 50.4 ± 7.60 mm Hg; telmisartan group, 75.0 ± 14.0 mm Hg to 57.4 ± 15.1 mm Hg), change was statistically remarkable only in telmisartan group. During eight weeks, there was no significant changes of RHI in both groups. There was a positive relationship between decrease of PP after 8 weeks and the improvement of endothelial function only in ramipril group, but not in telmisartan group (ramipril group, r = 0.671, p = 0.034; telmisartan group, r = -0.487, p = 0.153). CONCLUSIONS: Despite PP reduction effect favoring endothelial function, it's not correlated with RHI improvement with telmisartan. These findings suggest telmisartan itself may negatively influence endothelium dependent vasodilatation different from ramipril.

Cellular attachment and differentiation on titania nanotubes exposed to air- or nitrogen-based non-thermal atmospheric pressure plasma.

The surface topography and chemistry of titanium implants are important factors for successful osseointegration. However, chemical modification of an implant surface using currently available methods often results in the disruption of topographical features and the loss of beneficial effects during the shelf life of the implant. Therefore, the aim of this study was to apply the recently highlighted portable non-thermal atmospheric pressure plasma jet (NTAPPJ), elicited from one of two different gas sources (nitrogen and air), to TiO2 nanotube surfaces to further improve their osteogenic properties while preserving the topographical morphology. The surface treatment was performed before implantation to avoid age-related decay. The surface chemistry and morphology of the TiO2 nanotube surfaces before and after the NTAPPJ treatment were determined using a field-emission scanning electron microscope, a surface profiler, a contact angle goniometer, and an X-ray photoelectron spectroscope. The MC3T3-E1 cell viability, attachment and morphology were confirmed using calcein AM and ethidium homodimer-1 staining, and analysis of gene expression using rat mesenchymal stem cells was performed using a real-time reverse-transcription polymerase chain reaction. The results indicated that both portable nitrogen- and air-based NTAPPJ could be used on TiO2 nanotube surfaces easily and without topographical disruption. NTAPPJ resulted in a significant increase in the hydrophilicity of the surfaces as well as changes in the surface chemistry, which consequently increased the cell viability, attachment and differentiation compared with the control samples. The nitrogen-based NTAPPJ treatment group exhibited a higher osteogenic gene expression level than the air-based NTAPPJ treatment group due to the lower atomic percentage of carbon on the surface that resulted from treatment. It was concluded that NTAPPJ treatment of TiO2 nanotube surfaces results in an increase in cellular activity. Furthermore, it was demonstrated that this treatment leads to improved osseointegration in vitro.