Validation of gait analysis using smartphones: Reliability and validity.

Objective: This study aims to validate the reliability and validity of gait analysis using smartphones in a controlled environment. Methods: Thirty healthy adults attached smartphones to the waist and thigh, while an inertial measurement unit was fixed at the shank as a reference device; each participant was asked to walk six gait cycles at self-selected low, normal, and high speeds. Thirty-five cerebral small vessel disease patients were recruited to attach the smartphone to the thigh, performing single-task (ST), cognitive dual-task (DT1), and physical dual-task walking (DT2) to obtain gait parameters. Results: The results from the healthy group indicate that, regardless of whether attached to the thigh or waist, the smartphones calculated gait parameters with good reliability (ICC2,1 > 0.75) across three different walking speeds. There were no significant differences in the gait parameters between the smartphone attached to the thigh and the IMU across all three walking speeds (P > 0.05). However, significant differences were observed between the smartphone at the waist and the IMU during the stance phase, swing phase, stance time, and stride length at high speeds (P < 0.05). At the same time, measurements of other gait parameters were similar (P > 0.05). Patients demonstrated significant differences in the cadence, stride time, stance phase, swing phase, stance time, stride length, and walking speed between ST and DT1 (P < 0.05). Significant differences were observed in the stance phase, swing phase, stride length, and walking speed between ST and DT2 (P < 0.05). Conclusions: This study demonstrates the feasibility of using built-in smartphone sensors for gait analysis in a controlled environment.

[A study of cognitive impairment quantitative assessment method based on gait characteristics].

Alzheimer's disease (AD) is a common and serious form of elderly dementia, but early detection and treatment of mild cognitive impairment can help slow down the progression of dementia. Recent studies have shown that there is a relationship between overall cognitive function and motor function and gait abnormalities. We recruited 302 cases from the Rehabilitation Hospital Affiliated to National Rehabilitation Aids Research Center and included 193 of them according to the screening criteria, including 137 patients with MCI and 56 healthy controls (HC). The gait parameters of the participants were collected during performing single-task (free walking) and dual-task (counting backwards from 100) using a wearable device. By taking gait parameters such as gait cycle, kinematics parameters, time-space parameters as the focus of the study, using recursive feature elimination (RFE) to select important features, and taking the subject's MoCA score as the response variable, a machine learning model based on quantitative evaluation of cognitive level of gait features was established. The results showed that temporal and spatial parameters of toe-off and heel strike had important clinical significance as markers to evaluate cognitive level, indicating important clinical application value in preventing or delaying the occurrence of AD in the future.

The hydrolyzable gallotannin, penta-O-galloyl-ß-D-glucopyranoside, inhibits the formation of advanced glycation endproducts by protecting protein structure.

Glycation is a spontaneous process initiated by a condensation reaction between reducing sugars and proteins that leads to the formation of advanced glycation endproducts (AGEs). The in vivo accumulation of AGEs is associated with several chronic human diseases and, thus, the search for AGE inhibitors is of great research interest. Hydrolyzable tannins (gallotannins and ellagitannins) are bioactive plant polyphenols which show promise as natural inhibitors of glycation and AGE formation. Notably, the gallotannin, 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (PGG), is a key intermediate involved in the biosynthesis of hydrolyzable tannins in plants. Herein, we investigated the effects of PGG on the individual stages of protein glycation and on protein structure (using bovine serum albumin; BSA). MALDI-TOF data demonstrated that PGG inhibited early glycation by 75% while the synthetic AGE inhibitor, aminoguanidine (AG), was not active (both at 50 µM). In addition, PGG reduced the formation of middle and late stage AGEs by 90.1 and 60.5%, respectively, which was superior to the positive control, AG. While glycation induced conformational changes in BSA from α-helix to ß-sheets (from circular dichroism and congo red binding studies), PGG (at 50 µM) reduced this transition by 50%. Moreover, BSA treated with PGG was more stable in its structure and retained its biophysical properties (based on zeta potential and electrophoretic mobility measurements). The interaction between PGG and BSA was further supported by molecular docking studies. Overall, the current study adds to the growing body of data supporting the anti-AGE effects of hydrolyzable tannins, a ubiquitous class of bioactive plant polyphenols.

Polymyxin E sulfate-loaded liposome for intravenous use: preparation, lyophilization, and toxicity assessment in vivo.

Polymyxin E sulfate, a hydrophilic drug with high tissue toxicity, was formulated into a stable liposome to reduce its in vivo toxicity. The liposome was prepared using both a reverse phase evaporation and freezing-thawing method. The encapsulation efficiency was determined by high-performance liquid chromatography. The influence of the freezing-thawing process on the liposome's stability was evaluated using a centrifugation test. The dialysis method was employed to investigate the in vitro release profile of the drug-loaded liposome. The toxicity of the polymyxin E sulfate-loaded liposome was compared with the polymyxin E sulfate solution in Kunming mice by intravenous administration. A freeze-drying (lyophilization) technique was utilized to prepare the proliposome. A cryoprotectant formulation was optimized by the evaluation of the particle diameter and encapsulation efficiency of the redispersed proliposomes, while the influence of the concentration and method of the addition of the cryoprotectant on the protective effect was investigated as well. It was found that the stability and encapsulation efficiency of the liposome could be improved by the freezing-thawing process. The delayed drug release profile of the drug-loaded liposome was observed in vitro, and a comparison with the polymyxin E sulfate solution revealed that the in vivo toxicity of the polymyxin E sulfate-loaded liposome was significantly reduced. Sucrose and mannitol at a weight ratio of 1:0.8:0.6 (phospholipids:mannitol:sucrose) added inside displayed the greatest protective effect on the polymyxin E sulfate liposome during freeze-drying. The rehydrated proliposomes with optimized cryoprotectants produced an acceptable particle diameter (204.1 nm) and a satisfactory encapsulation efficiency percentage (51.48%), thus demonstrating a practical method for preparation of polymyxin E sulfate-loaded proliposome. A combination of the reverse phase evaporation and freezing-thawing methods was found to be suitable for the preparation of hydrophilic drug-loaded liposome. The toxicity of polymyxin E sulfate was reduced by its encapsulation in a liposome, thus constituting a promising drug delivery system suitable for further development. The method of addition had an insignificant effect on the appearance of the product but obviously influenced the particle diameter and encapsulation efficiency. The inside addition method produced a greater protective effect in this study.