Background: Insufficient data are available to support the routine use of tranexamic acid (TXA) in anterior cruciate ligament (ACL) surgeries with respect to administration method and frequency, exposure duration, dose, and adverse effects. Purpose: To investigate whether intra-articular (IA) administration of TXA could reduce hemarthrosis and postoperative pain in patients after ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 47 patients were included in this study, which was performed between July 2017 and May 2019. Single-bundle reconstructions using autologous hamstring tendon grafts were performed in all patients. The patients were randomized into 2 groups: the TXA group (received the index procedure with 100-mL IA injection of TXA [30 mg/mL]) and a control group (did not receive IA injection of TXA). No patients received a drain. Blood loss was calculated on the basis of hemoglobin balance at postoperative day (PD) 2. The visual analog scale (VAS) for pain score was assessed at PD 3. The midpatellar circumference was measured at PD 2 and PD 5. Knee range of motion (ROM) was evaluated 6 weeks after surgery. Results: The mean ± SD blood loss was 467 ± 242 mL in the TXA group and 558 ± 236 mL in the control group. No significant differences were found for blood loss ( P = .20), VAS pain scores ( P = .28), ROM at postoperative week 6 ( P = .61), or patellar circumference at PD 2 ( P = .75) and PD 5 ( P = .84). Conclusion: This study showed that IA administration of 3.0 g of TXA had no effect in reducing blood loss and postoperative pain after primary anatomic single-bundle ACL reconstruction using quadruple hamstring autografts. Registration: NCT04042688 ( ClinicalTrials.gov identifier).

We report Brownian dynamics simulations of tracer diffusion in regularly crosslinked polymer networks in order to elucidate the transport of a tracer particle in polymer networks. The average mesh size of homogeneous polymer networks is varied by assuming different degrees of crosslinking or swelling, and the size of a tracer particle is comparable to the average mesh size. Simulation results show subdiffusion of a tracer particle at intermediate time scales and normal diffusion at long times. In particular, the duration of subdiffusion is significantly prolonged as the average mesh size decreases with increasing degree of crosslinking, for which long-time diffusion occurs via the hopping processes of a tracer particle after undergoing rattling motions within a cage of the network mesh for an extended period of time. On the other hand, the cage dynamics and hopping process are less pronounced as the mesh size decreases with increasing polymer volume fractions. The interpretation is provided in terms of fluctuations in network mesh size: at higher polymer volume fractions, the network fluctuations are large enough to allow for collective, structural changes of network meshes, so that a tracer particle can escape from the cage, whereas, at lower volume fractions, the fluctuations are so small that a tracer particle remains trapped within the cage for a significant period of time before making infrequent jumps out of the cage. This work suggests that fluctuation in mesh size, as well as average mesh size itself, plays an important role in determining the dynamics of molecules and nanoparticles that are embedded in tightly meshed polymer networks.

Background:Oxidative stress-induced cell damage is common in the etiology of several neurobiological disorders, including Alzheimer's disease and Parkinson's disease. In a case study, nobiletin-rich Citrus reticulata peels could prevent the progression of cognitive impairment in donepezil-preadministered Alzheimer's disease patients.Objective:In this study, we investigated the effects and underlying mechanism of nobiletin and Citrus unshiu immature peel (CUIP) water extract, which contains nobiletin as a major compound, on hydrogen peroxide-induced oxidative stress in HT22 cells, a murine hippocampal neuronal model.Materials and Methods:HT22 cells were treated with hydrogen peroxide in the presence or absence of various concentrations of CUIP and nobiletin. Cytotoxicity and apoptotic protein levels were measured by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and Western blotting.Results:Pretreatment with CUIP and nobiletin inhibited cell death due to hydrogen peroxide. Hydrogen peroxide-induced the expression of phospho-Jun N-terminal kinases (p-JNK) and p-p38 proteins in HT22 cells; however CUIP and nobiletin suppressed p-JNK and p-p38 without changing JNK or p38. Regarding apoptosis, caspase 3, B-cell lymphoma 2 (Bcl-2), and Bax protein expression was determined. CUIP and nobiletin suppressed caspase 3 and Bax expression, but they induced Bcl-2 expression in HT22 cells.Conclusion:These results show that CUIP and nobiletin can protect against hydrogen peroxide-induced cell death in HT22 neurons via mitogen-activated protein kinases and apoptotic pathways.

Achillea alpina is widely distributed in Korea and is often used as a folk medicine for stomach disorders. Although a previous study isolated antioxidant compounds (flavonoid O‐glucoside, sesquiterpene) from this plant, no systematic study of its chemical constituents had been reported. The present study aimed to identify the phytochemicals present in a methanol extract of A. alpina, assess their potential antioxidant activities in vitro, and determine their effects on melanogenesis in B16F10 melanoma cells. Column chromatographic separation of aqueous fractions of A. alpina led to the isolation of 17 compounds. The chemical structures of these compounds were determined using spectroscopic data from electrospray ionization‐mass spectrometry and nuclear magnetic resonance. To the best of our knowledge, the present study is the first to identify compounds 2–10 and 12–17 in A. alpina. Furthermore, compound 6 possessed powerful antioxidant activity, while compound 15 suppressed intracellular tyrosinase activity and thus reduced melanogenesis in B16F10 cells. Therefore, our research suggested that these naturally occurring compounds have the potential to reduce oxidative stress and promote skin whitening. Further investigations will be required to elucidate the mechanisms underlying the antioxidant and antityrosinase activities of these compounds.

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