Peroneal reaction time delayed but dynamic single-legged stability retained in collegiate footballers during a simulated prolonged football protocol

Delayed peroneal reaction time and impaired single-legged dynamic stability were risk factors of lateral ankle sprain (LAS), yet no study explored the change of them during a football match. The aim is to explore the change of peroneal reaction time and single-legged dynamic stability during a football simulation protocol. Twelve collegiate football players voluntarily completed a 105-minute football match simulation protocol in which peroneal reaction time, root mean square of mediolateral ground reaction force in first 0.4s (RMS ML 0.4), and the mean mediolateral ground reaction force in the late stage (late dynamic MLGRF), were measured for both legs at 15-minute intervals during the protocol. Peroneal reaction time was tested using an electromyography (EMG) system. The ground reaction force variables were measured from GRF data after a single-legged drop-jump landing. Repeated measures one-way MANOVA was conducted to evaluate variables over time and leg dominance. Statistical significance was set at p < 0.05 level. Peroneal reaction time significantly increased for both legs at 45 minutes and after 60 minutes. RMS ML 0.4 of both legs and late dynamic MLGRF for dominant leg remained unchanged throughout the protocol and late dynamic MLGRF for non-dominant leg significantly reduced at the 90th minute

Enhanced stability of oral insulin in targeted peptide ligand trimethyl chitosan nanoparticles against trypsin

<div><p></p><p>Oral insulin delivery is often limited by protease degradation. 2-(Dimethylamino)-2-oxoethyl 4-(4-guanidinobenzoyloxy)phenylacetate methanesulphonate (Camostat mesylate) is reported to have the ability to inhibit trypsin activity, which is the main protease responsible for protein degradation. This study attempted to form a novel nanoparticle by covalently conjugating 4-(2-(2-aminoethylamino)-2-oxoethyl)phenyl 4-guanidinobenzoyloxy (FOY-251), an active derivative of camostat mesylate, to the backbone of poly (γ-glutamic acid) (γ-PGA), in order to improve insulin stability against protease. Goblet cell targeting CSKSSDYQC (CSK) peptide was demonstrated to effectively improve the epithelial absorption of insulin. Therefore, the novel nanoparticle was prepared by mixing cationic peptide modified trimethyl chitosan (TMC-CSK) with anionic γPGA-FOY conjugate using multi-ion crosslinked method. Results showed that not only the γPGA-FOY conjugate but also the prepared novel nanoparticle could inhibit trypsin activity both <i>in vitro</i> environment and on the intestinal mucosal surface. This study would be beneficial for peptide modified nanoparticles in oral insulin delivery.</p></div

A lateral ankle sprain during a lateral backward step in badminton: a case report of a televised injury incident

Background: This study presents a kinematic analysis of an acute lateral ankle sprain incurred during a televised badminton match. The kinematics of this injury were compared to those of 19 previously reported cases in the published literature.Methods: Four camera views of an acute lateral ankle sprain incurred during a televised badminton match were synchronised and rendered in 3-dimensional animation software. A badminton court with known dimensions was built in a virtual environment, and a skeletal model scaled to the injured athlete’s height was used for skeletal matching. The ankle joint angle and angular velocity profiles of this acute injury were compared to the summarised findings from 19 previously reported cases in the published literature.Results: At foot strike, the ankle joint was 2 degrees everted, 33 degrees plantarflexed, and 18 degrees internally rotated. Maximum inversion of 114 degrees and internal rotation of 69 degrees was achieved at 0.24 and 0.20 seconds after foot strike, respectively. After the foot strike, the ankle joint moved from an initial position of plantarflexion to dorsiflexion – from 33 degrees plantarflexion to 53 degrees dorsiflexion (range = 86 degrees). Maximum inversion, dorsiflexion, and internal rotation velocity were 1262, 961, and 677 degree/s at 0.12 second after foot strike.Conclusion: A forefoot landing posture with a plantarflexed and internally rotated ankle joint configuration could incite an acute lateral ankle sprain injury in badminton. Prevention of lateral ankle sprains in badminton should focus on the control and stability of the ankle joint angle during forefoot landings, especially when the athletes perform a combined lateral and backward step. </div

Biomimetic Viruslike and Charge Reversible Nanoparticles to Sequentially Overcome Mucus and Epithelial Barriers for Oral Insulin Delivery

Nanoparticles (NPs) for oral delivery of peptide/protein drugs are largely limited due to the coexistence of intestinal mucus and epithelial barriers. Sequentially overcoming these two barriers is intractable for a single nanovehicle due to the requirements of different or even contradictory surface properties of NPs. To solve this dilemma, a mucus-penetrating virus-inspired biomimetic NP with charge reversal ability (P-R8-Pho NPs) was developed by densely coating poly­(lactic-<i>co</i>-glycolic acid) NPs with cationic octa-arginine (R8) peptide and specific anionic phosphoserine (Pho). The small size (81.81 nm) and viruslike neutral charged surface (−2.39 mV) of the biomimetic NPs achieved rapid mucus penetration, which was almost equal to that of the conventional PEGylated mucus-penetrating nanoparticles. The hydrolysis of surface-anchored anionic Pho was achieved by intestinal alkaline phosphatase, which led to the turnover of ζ potential to positive (+7.37 mV). This timely charge reversal behavior also exposed cationic R8 peptide and induced efficient cell-penetrating peptide (CPP)-mediated cellular uptake and transepithelial transport on Caco-2/E12 cocultured cell model. What’s more, P-R8-Pho NPs showed excellent stability in simulated gastrointestinal conditions and enhanced absorption in intestine in vivo. Finally, oral administration of insulin-loaded P-R8-Pho NPs enabled to induce a preferable hypoglycemic effect and a 1.9-fold higher oral bioavailability was achieved compared with single CPP-modified P-R8 NPs on diabetic rats. The combinative application of biomimetic mucus-penetrating strategy and enzyme-responsive charge reversal strategy in a single nanovehicle could sequentially overcome mucus and epithelial barriers, thus showing great potential for the oral peptide/protein delivery

Overcoming the Diffusion Barrier of Mucus and Absorption Barrier of Epithelium by Self-Assembled Nanoparticles for Oral Delivery of Insulin

Nanoparticles (NPs) have demonstrated great potential for the oral delivery of protein drugs that have very limited oral bioavailability. Orally administered NPs could be absorbed by the epithelial tissue only if they successfully permeate through the mucus that covers the epithelium. However, efficient epithelial absorption and mucus permeation require very different surface properties of a nanocarrier. We herein report self-assembled NPs for efficient oral delivery of insulin by facilitating both of these two processes. The NPs possess a nanocomplex core composed of insulin and cell penetrating peptide (CPP), and a dissociable hydrophilic coating of <i>N</i>-(2-hydroxypropyl) methacrylamide copolymer (pHPMA) derivatives. After systematic screening using mucus-secreting epithelial cells, NPs exhibit excellent permeation in mucus due to the “mucus-inert” pHPMA coating, as well as high epithelial absorption mediated by CPP. The investigation of NP behavior shows that the pHPMA molecules gradually dissociate from the NP surface as it permeates through mucus, and the CPP-rich core is revealed in time for subsequent transepithelial transport through the secretory endoplasmic reticulum/Golgi pathway and endocytic recycling pathway. The NPs exhibit 20-fold higher absorption than free insulin on mucus-secreting epithelium cells, and orally administered NPs generate a prominent hypoglycemic response and an increase of the serum insulin concentration in diabetic rats. Our study provides the evidence of using pHPMA as dissociable “mucus-inert” agent to enhance mucus permeation of NPs, and validates a strategy to overcome the multiple absorption barriers using NP platform with dissociable hydrophilic coating and drug-loaded CPP-rich core

A novel ligand conjugated nanoparticles for oral insulin delivery

<p>In order to enhance the interaction between nanocarrier and gastrointestinal epithelial cells, we developed nanoparticles (NPs) modified with targeting ligand FQSIYPpIK (FQS), which specifically interact with integrin αvβ3 receptor expressing on the intestinal epithelium. The targeting NPs were prepared by coating the insulin-loaded poly(lactide-co-glycolide)–monomethoxy-poly(polyethylene glycol) micelle cores with FQS modified trimethyl chitosan chloride. In <i>in vitro</i> study, the fabricated NPs showed ameliorated drug release profile and improved enzymatic stability compared with micelles alone. In the integrin αvβ3 receptor over-expressed Caco-2 cells model, FQS modified NPs exhibited significantly accelerated intracellular uptake due to the active ligand–receptor mediation. Meanwhile, the targeting NPs also showed enhanced transport across the Caco-2 monolayer cells via both transcellular and paracellular pathways. Besides, orally administered FQS modified NPs produced a prominent hypoglycemic response and an increase of the serum insulin concentration in diabetic rats. Both <i>in vitro and in vivo</i> results demonstrated the FQS peptide modified NPs as promising intestinal cell-targeting nanocarriers for efficient oral delivery of insulin.</p

Penetratin Derivative-Based Nanocomplexes for Enhanced Intestinal Insulin Delivery

Sufficient mucosal permeability is the bottleneck problem in developing an efficient intestinal delivery system of insulin. Cell-penetrating peptide-based nanocomplexes for the enhanced mucosal permeation of insulin were developed in this study. Penetratin, a cell-penetrating peptide was site-specifically modified with a bis-β-cyclodextrin group. Insulin-loaded nanocomplexes were prepared by self-assembly using penetratin or its bis-β-cyclodextrin modified derivative (P-bis-CD). A stronger intermolecular interaction and higher complex stability were observed for P-bis-CD nanocomplexes than the penetratin nanocomplexes. P-bis-CD nanocomplexes were significantly more efficient for the permeation of insulin as compared to the penetratin nanocomplexes both <i>in vitro</i> and <i>in situ</i>. Interestingly, different cellular internalization mechanisms were observed for the two nanocomplexes. In diabetic rats, intestinal administration of P-bis-CD nanocomplexes resulted in a prominent hypoglycemic effect which lasted for 6 h with maximum inhibitory rate at 60%. The relative pharmacological availability and bioavailability of P-bis-CD nanocomplexes were 10.6% and 7.1%, which were 3.0-fold and 2.3-fold higher than that of penetratin nanocomplexes, respectively. In addition, no sign of toxicity was observed after 7 consecutive days of administration of P-bis-CD nanocomplexes with endotoxin. These results demonstrated that P-bis-CD was a promising epithelium permeation enhancer for insulin and suggested that the chemical modification of cell penetration peptides was a feasible strategy to enhance their potential

Enhanced Oral Delivery of Protein Drugs Using Zwitterion-Functionalized Nanoparticles to Overcome both the Diffusion and Absorption Barriers

Oral delivery of protein drugs based on nanoparticulate delivery system requires permeation of the nanoparticles through the mucus layer and subsequent absorption via epithelial cells. However, overcoming these two barriers requires very different or even contradictory surface properties of the nanocarriers, which greatly limits the oral bioavailability of macromolecular drugs. Here we report a simple zwitterions-based nanoparticle (NP) delivery platform, which showed a great potency in simultaneously overcoming both the mucus and epithelium barriers. The dense and hydrophilic coating of zwitterions endows the NPs with excellent mucus penetrating ability. Moreover, the zwitterions-based NPs also possessed excellent affinity with epithelial cells, which significantly improved (4.5-fold) the cellular uptake of DLPC NPs, compared to PEGylated NPs. Our results also indicated that this affinity was due to the interaction between zwitterions and the cell surface transporter PEPT1. Moreover, the developed NPs loaded with insulin could induce a prominent hypoglycemic response in diabetic rats following oral administration. These results suggest that zwitterions-based NPs might provide a new perspective for oral delivery of protein therapeutics

Involvement of WRKY Transcription Factors in Abscisic-Acid-Induced Cold Tolerance of Banana Fruit

Phytohormone abscisic acid (ABA) and plant-specific WRKY transcription factors (TFs) have been implicated to play important roles in various stress responses. The involvement of WRKY TFs in ABA-mediated cold tolerance of economical fruits, such as banana fruit, however remains largely unknown. Here, we reported that ABA application could induce expressions of ABA biosynthesis-related genes <i>MaNCED1</i> and <i>MaNCED2</i>, increase endogenous ABA contents, and thereby enhance cold tolerance in banana fruit. Four banana fruit WRKY TFs, designated as MaWRKY31, MaWRKY33, MaWRKY60, and MaWRKY71, were identified and characterized. All four of these MaWRKYs were nuclear-localized and displayed transactivation activities. Their expressions were induced by ABA treatment during cold storage. More importantly, the gel mobility shift assay and transient expression analysis revealed that MaWRKY31, MaWRKY33, MaWRKY60, and MaWRKY71 directly bound to the W-box elements in <i>MaNCED1</i> and <i>MaNCED2</i> promoters and activated their expressions. Taken together, our findings demonstrate that banana fruit WRKY TFs are involved in ABA-induced cold tolerance by, at least in part, increasing ABA levels via directly activating <i>NECD</i> expressions

Characterization of a Transcriptional Regulator, BrWRKY6, Associated with Gibberellin-Suppressed Leaf Senescence of Chinese Flowering Cabbage

Phytohormone gibberellin (GA) and plant-specific WRKY transcription factors (TFs) are reported to play important roles in leaf senescence. The association of WRKY TFs with GA-mediated leaf senescence of economically important leafy vegetables like Chinese flowering cabbage, however, remains largely unknown. In this study, we showed that exogenous application of GA₃ suppressed Chinese flowering cabbage leaf senescence, with GA₃-treated cabbages maintaining a higher level of maximum quantum yield (Fv/Fm) and total chlorophyll content. GA₃ treatment also led to lower electrolyte leakage and expression level of a series of senescence-associated genes (SAGs) including <i>BrSAG12</i> and <i>BrSAG19</i>, and chlorophyll catabolic genes (CCGs) <i>BrPPH1</i>, <i>BrNYC1</i>, and <i>BrSGRs</i>. In addition, higher transcription levels of GA biosynthetic genes <i>BrKAO2</i> and <i>BrGA20ox2</i> were found after GA₃ treatment. More importantly, a GA-repressible, nuclear-localized WRKY TF, BrWRKY6, a homologue of the Arabidopsis AtWRKY6, was identified and characterized. BrWRKY6 was GA-repressible and localized in the nucleus. Further experiments revealed that BrWRKY6 repressed the expression of <i>BrKAO2</i> and <i>BrGA20ox2</i>, while it activated <i>BrSAG12</i>, <i>BrNYC1</i>, and <i>BrSGR1</i>, through binding to their promoters via the W-box cis-element. Together, the novel GA–WRKY link reported in our study provides new insight into the transcriptional regulation of GA-suppressed leaf senescence in Chinese flowering cabbage