Simple and Efficient Detection Scheme of Two-Color Fluorescence Correlation Spectroscopy for Protein Dynamics Investigation from Nanoseconds to Milliseconds.

Nanosecond resolved fluorescence correlation spectroscopy (ns-FCS) based on two-color fluorescence detection is a powerful strategy for investigating the fast dynamics of biological macromolecules labeled with donor and acceptor fluorophores. The standard methods of ns-FCS use two single-photon avalanche diodes (SPADs) for the detection of single-color signals (four SPADs for two-color signals) to eliminate the afterpulse artifacts of SPAD at the expense of the efficiency of utilizing photon data in the calculation of correlograms. Herein, we demonstrated that hybrid photodetectors (HPDs) enable the recording of fluorescence photons in ns-FCS based on the minimal system using two HPDs for the detection of two-color signals. However, HPD exhibited afterpulses at a yield with respect to the rate of photodetection (<10-4) much lower than that of SPADs (∼10-2), which could still hamper correlation measurements. We demonstrated that the simple subtraction procedure could eliminate afterpulse artifacts. While the quantum efficiency of photodetection for HPDs is lower than that for high-performance SPADs, the developed system can be practically used for two-color ns-FCS in a time domain longer than a few nanoseconds. The fast chain dynamics of the B domain of protein A in the unfolded state was observed using the new method.

The anteroposterior distance between the posterior edge of the medial tibial condyle and the posterior edge of the fibular head in the lateral view can be a reference in determining the axis perpendicular to the tibial anteroposterior axis.

BACKGROUND: Obtaining an accurate tibial lateral view is important during high tibial osteotomy. This study investigated whether the posterior edge of the medial/lateral tibial condyle (PEMTC/PELTC) and the posterior edge of the fibular head (PEFH) in a lateral view could be a reference for determining the accurate tibial lateral view. METHODS: A total of 75 lower limbs in 38 subjects were evaluated in this study. In order to target healthy knees, subjects undergoing primary total hip arthroplasty were selected. The MF/LF, comprising the anteroposterior distance between PEMTC/PELTC and PEFH, was measured on the lateral view of the tibial bone model based on the tibial anteroposterior (AP) axis (true lateral view: TLV). In addition, measurements were calculated in the model with a 10° external/internal rotation. Using these measurements, linear regression analysis was performed to predict the tibial rotation with MF/LF. RESULTS: The mean MF/LF was 0.9/4.6 mm (P < 0.001). MF and LF increased with incremental tibial rotation. Regression formulas were derived from these results as follows: Tibial rotation = (1) -1.01 + 1.06 × MF (R2 = 0.87, P < 0.001), (2) -8.70 + 1.86 × LF (R2 = 0.51, P < 0.001). The mean tibial rotation angle when MF was 0 mm was -0.9°. CONCLUSIONS: Based on formula (1) and actual measurements, the mean tibial rotation angle when MF is 0 mm is an internal rotation of about 1°. Therefore, a lateral view, in which PEMTC and PEFH are seen colinearly, can be the approximate TLV. The MF can be a suitable intraoperative reference in determining TLV.

The medial tangent of the proximal tibia is a suitable extra-articular landmark in determining the tibial anteroposterior axis.

BACKGROUND: Tibial rotational alignment in total knee arthroplasty (TKA) is generally determined based on intra-articular structure, and can be difficult to ascertain in some cases. The aim of this study was to investigate whether the medial tangent angle of the tibia (MTAT) could be useful in determining the anteroposterior axis of the tibia. METHODS: This study was performed on 103 lower limbs in 53 patients who underwent primary total hip arthroplasty. The selection criteria for our study were based on the assumption that knees in patients undergoing THA exhibit fewer degenerative changes than knees in patients undergoing TKA. Using computed tomography images, the MTAT, comprising the medial tangent of the proximal tibia and the anteroposterior (AP) axis of the tibia, was measured on three horizontal planes: at the distal edge of the tibial tubercle (A), at 5 cm distally (B), and at 10 cm further distally (C). The tibial medial surface was grouped into three classes according to shape: valley type, flat type, and hill type. The percentage at which these shapes were observed in each group was also calculated. Measurement reliability was calculated using the intraclass correlation coefficient. RESULTS: The angles were 45.2° (interquartile range: IR 43.0-47.7) at A, 42.7° (IR 38.7-45.9) at B, and 42.4° (IR 38.2-45.9) at C. Intra-rater reliability and inter-rater reliability was 0.982 and 0.974 at A, 0.810 and 0.411 at B, and 0.940 and 0.811 at C, respectively. Regarding the tibial medial surface, the valley type was observed in all cases at A, and the hill type was observed in the highest percentage of cases at B and C. CONCLUSIONS: The MTAT was approximately 45° at level A, and reproducibility was the highest among the three groups. The two points forming the valley on the tibial medial surface were bony ridges. Therefore, the medial tangent of the tibia at level A could be easily determined. Because the distal edge of the tibial tubercle exists at the surgical area and the extra-articular area, it can be a suitable intraoperative, extra-articular landmark in determining the tibial AP axis, even for revision TKA.

Higher PGD2 production by synovial mast cells from rheumatoid arthritis patients compared with osteoarthritis patients via miR-199a-3p/prostaglandin synthetase 2 axis.

We previously reported that synovial mast cells (MCs) from patients with rheumatoid arthritis (RA) produced TNF-α in response to immune complexes via FcγRI and FcγRIIA. However, the specific functions of synovial MCs in RA remain unclear. This study aimed to elucidate those functions. Synovial tissues and fluid were obtained from RA and osteoarthritis (OA) patients undergoing joint replacement surgery. Synovium-derived, cultured MCs were generated by culturing dispersed synovial cells with stem cell factor. We performed microarray-based screening of mRNA and microRNA (miRNA), followed by quantitative RT-PCR-based verification. Synovial MCs from RA patients showed significantly higher prostaglandin systhetase (PTGS)1 and PTGS2 expression compared with OA patients' MCs, and they produced significantly more prostaglandin D2 (PGD2) following aggregation of FcγRI. PGD2 induced IL-8 production by human group 2 innate lymphoid cells, suggesting that PGD2-producing MCs induce neutrophil recruitment into the synovium of RA patients. PTGS2 mRNA expression in RA patients' MCs correlated inversely with miRNA-199a-3p expression, which down-regulated PTGS2. RA patients' synovial fluid contained significantly more PGD2 compared with OA patients' fluid. Synovial MCs might regulate inflammation in RA through hyper-production of PGD2 following FcRγ aggregation. Our findings indicate functional heterogeneity of human MCs among diseases.

Activation of inflammation and resolution pathways of lipid mediators in synovial fluid from patients with severe rheumatoid arthritis compared with severe osteoarthritis.

BACKGROUND: The upregulation of the cyclooxygenase and lipoxygenase pathways of arachidonic acid is thought to be involved in the development of rheumatoid arthritis. Recently, the presence of specialized pro-resolving lipid mediators in synovial tissues from patients with osteoarthritis has been reported. OBJECTIVE: To clarify the quantitative and qualitative changes in lipid mediators in the synovium of severe rheumatoid arthritis patients, we compared the profiles of lipid mediators in synovial fluid obtained from patients with severe rheumatoid arthritis and from those with severe osteoarthritis. METHODS: We enrolled 18 patients with rheumatoid arthritis and 26 patients with osteoarthritis. All the patients had undergone total knee replacement surgery. Synovial fluid samples had been obtained during the surgery. Lipid profiling in the synovial fluid from these patients was performed using liquid chromatography-tandem mass spectrometry/mass spectrometry. RESULTS: Among the 150 oxidized fatty acids examined so far, 119 were substantially detected in synovial fluid from the patients. Not only the concentrations of pro-inflammatory lipid mediators such as prostaglandins and leukotrienes, but also those of specialized pro-resolving lipid mediators such as lipoxins, resolvins, and protectin D1 were significantly higher in synovial fluid obtained from rheumatoid arthritis patients than from synovial fluid obtained from osteoarthritis patients. CONCLUSION: The activation of both inflammation and resolution pathways of lipid mediators might be a fatty acid signature in the synovial fluid of patients with severe rheumatoid arthritis. Inflammatory, anti-inflammatory and pro-resolving mediators in synovial fluid could be good biomarkers for differentiating between severe rheumatoid arthritis and severe osteoarthritis.

Treatment of cloth with a fabric softener ameliorates skin dryness.

Dry skin is a condition characterized by impaired skin barrier function including atopic dermatitis and senile eczemas. Fabric softening chemicals (FSC) smoothens the surface of fabrics and thus decreases friction with the skin. Scientific evaluation of fabric softener on skin dryness is very limited. We evaluated the effectiveness and safety of FSC-treated T-shirts in subjects with dry skin. This is a randomized double-blind control study that included 40 male volunteers with apparent dry skin. Subjects were randomly divided into two groups: 20 men received 28 pieces of FSC-treated T-shirts wearing them for 4 weeks, and another 20 men received non-treated T-shirts. The effect of trial was evaluated by visual grading, subjective symptom, stratum corneum water content (SCWC), transepidermal water loss (TEWL), and dermoscopic skin surface analysis on days 0, 7, 14 and 28. A significant improvement of SCWC was observed in the skin of the shoulder (days 7-28) and lateral abdomen (day 14) wearing the treated T-shirts, but not in the non-treated T-shirts. In a stratified analysis of the low and high SCWC group, significant improvement was identified in the low SCWC groups but not in high SCWC groups. The visual grading of the shoulder improved significantly in the treated T-shirts group. No significant improvement was found in TEWL, dermoscopic analysis and subjective symptom in both groups. No remarkable side-effect was identified throughout this investigation. Addition of a fabric softener during clothes laundering is a potent preventive tool for dry skin.