Effect of loading history on material properties of human heel pad: an in-vivo pilot investigation during gait.

BACKGROUND: This study was aimed to develop a novel dynamic measurement technique for testing the material properties and investigating the effect of continuous compression load on the structural and mechanical properties of human heel pad during actual gait. METHODS: The dual fluoroscopic imaging system (DFIS) and dynamic foot-ground contact pressure-test plate were used for measuring the material properties, including primary thickness, peak strain, peak stress, elastic modulus, viscous modulus and energy dissipation rate (EDR), both at time zero and following continuous loading. Ten healthy pilot subjects, aged from 23 to 72 (average: 46.5 ± 17.6), were enrolled. A "three-step gait cycle" is performed for all subjects, with the second step striking at a marked position on the force plate with the heel to maintain the location of the tested foot to be in the view of fluoroscopes. The subjects were measured at both relaxed (time-zero group) and fatigue (continuous-loading group) statuses, and the left and right heels were measured using the identical procedures. RESULTS: The peak strain, peak stress, elastic modulus, and EDR are similar before and after continuous load, while the viscous modulus was significantly decreased (median: 43.9 vs. 20.37 kPa•s; p < 0.001) as well as primary thicknesses (median: 15.99 vs. 15.72 mm; p < 0.001). Age is demonstrated to be moderately correlated with the primary thicknesses both at time zero (R = -0.507) and following continuous load (R = -0.607). The peak stress was significantly correlated with the elastic modulus before (R = 0.741) and after continuous load (R = 0.802). The peak strain was correlated with the elastic modulus before (R = -0.765) and after continuous load (R = -0.801). The correlations between the viscous modulus and peak stress/ peak strain are similar to above(R = 0.643, 0.577, - 0.586 and - 0.717 respectively). The viscous modulus is positively correlated with the elastic modulus before (R = 0.821) and after continuous load (R = 0.784). CONCLUSIONS: By using dynamic fluoroscopy combined with the plantar pressure plate, the in vivo viscoelastic properties and other data of the heel pad in the actual gait can be obtained. Age was negatively correlated with the primary thickness of heel pad and peak strain, and was positively correlated with viscous modulus. Repetitive loading could decrease the primary thickness of heel pad and viscous modulus.

A Joy-Stick Assistant Three-Dimensional Modified Technique of Minimally Invasive Surgery for Mild or Moderate Hallux Valgus.

BACKGROUND: Minimally invasive surgery (MIS) such as minimally invasive chevron osteotomy and Akin osteotomy (MICA) has become popular in the treatment of hallux valgus. However, how to correct three-dimensional deformities in hallux valgus effectively and simply in MICA is still difficult. Special equipment is required in MICA as has been reported before. It is meaningful and necessary to reduce the reliance on special equipment in MICA. METHODS: From January 2021 to July 2022, patients with mild or moderate hallux valgus were treated with a joy-stick assistant three-dimensional modified technique (Joy-stick 3D technique) of MIS. VAS, AOFAS Hallux MTP-IP scores, hallux valgus angle (HVA), intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA) were measured pre- and postoperatively at the last follow-up of at least 6 months. Scores and radiologic angles were compared using paired sample t-test. RESULTS: A total of 36 cases were included. HVA, IMA, and DMAA were (22.3 ± 6.1)°, (14.0 ± 3.2)°, and (8.9 ± 3.2)° preoperatively, and decreased to (7.0 ± 1.8)°, (3.7 ± 1.0)°, and (3.3 ± 1.1)° postoperatively. VAS decreased from 4.3 ± 1.7 to 0.7 ± 0.7. AOFAS Hallux MTP-IP scores improved from 68.6 ± 7.6 to 92.9 ± 6.1. Comparing mild and moderate cases, though HVA, IMA, and DMAA were significantly different preoperatively, the angles became statistically similar after surgery. CONCLUSIONS: A joy-stick assistant three-dimensional modified technique is proposed to control the three-dimensional position of the metatarsal head and to reduce dependence on special tools. Mild and moderate hallux valgus deformities are effectively corrected using Joy-stick 3D technique.

A fluoroscopic imaging-guided computational analyses to inform internal tissue loads within fat pad of the diabetic foot during gait.

To accurately predict internal tissue loads for early diagnostics of diabetic foot ulcerations, a novel data-driven computational analysis was conducted. A dedicated dual fluoroscopic system was combined with a pressure mat to simultaneously characterize foot motions and soft tissue's material properties during gait. Finite element (FE) models of the heel pad of a diabetic patient were constructed with 3D trajectories of the calcaneus applied as boundary conditions to simulate gait events. The tensile and compressive stresses occurring in the plantar tissue were computed. Predictions of the layered tissue FE model with anatomically-accurate heel pad structures (i.e., fat and skin) were compared with those of the traditional lumped tissue (i.e., homogeneous) models. The influence of different material properties (patient-specific versus generic) on internal tissue stresses was also investigated. The results showed the peak tensile stresses in the layered tissue model were predominantly found in the skin and distributed towards the circumferential regions of the heel, while peak compressive stresses in the fat tissue-bone interface were up to 51.4% lower than those seen in the lumped models. Performing FE analyses at four different phases of walking revealed that ignorance of layered tissue structures resulted in an unphysiological increase of peak-to-peak value of stress fluctuation in the fat and skin tissue components. Thus, to produce more clinical-relevant predictions, foot FE models are suggested to include layered tissue structures of the plantar tissue for an improved estimation of internal stresses in the diabetic foot in gait.

An effector of Erysiphe necator translocates to chloroplasts and plasma membrane to suppress host immunity in grapevine.

The powdery mildew (Erysiphe necator) is a prevalent pathogen hampering grapevine growth in the vineyard. An arsenal of candidate secreted effector proteins (CSEPs) was encoded in the E. necator genome, but it is largely unclear what role CSEPs plays during the E. necator infection. In the present study, we identified a secreted effector CSEP080 of E. necator, which was located in plant chloroplasts and plasma membrane. Transient expressing CSEP080 promotes plant photosynthesis and inhibits INF1-induced cell death in tobacco leaves. We found that CSEP080 was a necessary effector for the E. necator pathogenicity, which interacted with grapevine chloroplast protein VviB6f (cytochrome b6-f complex iron-sulfur subunit), affecting plant photosynthesis. Transient silencing VviB6f increased the plant hydrogen peroxide production, and the plant resistance to powdery mildew. In addition, CSEP080 manipulated the VviPE (pectinesterase) to promote pectin degradation. Our results demonstrated the molecular mechanisms that an effector of E. necator translocates to host chloroplasts and plasma membrane, which suppresses with the grapevine immunity system by targeting the chloroplast protein VviB6f to suppress hydrogen peroxide accumulation and manipulating VviPE to promote pectin degradation.

The potentially dangerous zone of the dorsomedial cutaneous nerve in minimally invasive surgery for hallux valgus: a cadaveric study.

BACKGROUND: This study aims to describe the distribution of the dorsomedial cutaneous nerve (DMCN) in the middle and proximal parts of the metatarsal from a lateral view. The purpose is to provide guidance to surgeons in protecting the nerve during the 3rd and 4th generation minimally invasive surgery (MIS) for hallux valgus (HV). METHODS: A total of 20 cadaveric feet were dissected to expose the course of the DMCN and sentinel vein. Measurements of the distances between the nerve/vein and the upper border of the metatarsal, as well as the height of the metatarsal, were taken from a lateral view. The distribution area was then described in proportion. RESULTS: At the base of the metatarsal, the DMCN was distributed in the upper 25.7% of the area. When it reached the middle of the metatarsal, the DMCN was distributed in the upper 13.2-47.2% of the area. As for the sentinel vein, it was distributed in the upper 23.5-71.9% and upper 4.1-52.7%, respectively, at these two positions. CONCLUSIONS: The area, which is above the line connecting the upper 1/4 point at the base of the first metatarsal and the 1/2 point at the middle of the first metatarsal, is a dangerous zone for the DMCN. Avoiding the zone is recommended during MIS for HV.

Is a Preoperative MRI Scan Necessary for Acute Achilles Tendon Rupture?

BACKGROUND: Different treatment methods have been developed for acute Achilles tendon rupture (ATR), including conservative treatment, minimally invasive or transdermal surgery, and open surgery, and there is no consensus about which method is superior. It is important to clarify the presence of Achilles tendon (AT) degeneration, the rupture site, and the rupture shape before surgery to determine whether minimally invasive or open surgery should be selected, thereby reducing the re-rupture rate following acute ATR. The aim of this study was to investigate the diagnostic value of MRI in identifying the presence of AT degeneration, the rupture site, and the rupture shape for acute closed ATR. METHODS: From January 2016 to December 2019, patients with acute closed ATR who had undergone repair surgery were retrospectively enrolled. All patients received MRI examination, and the distance between the insertion site and broken end and the rupture shape (types I, II, and III) were independently determined by two observers. Then, the stump of the AT was exposed during the operation. The rupture site and rupture shape were recorded and compared and analyzed with the MRI results. Consistency analyses (using Cohen's kappa coefficient or intraclass correlation coefficient-ICC) and calculation of diagnostic performance indexes were, respectively, conducted to evaluate the diagnostic value of the MRI. RESULTS: This study included 47 consecutive patients with acute ATR, with an average age of 38.4 years. Among them, 40 were male, and seven were female. The intraoperative exploration demonstrated a total of 34 (72.3%), 10 (21.3%), and three (6.4%) patients with type I, II, and III ruptures, respectively. The average distance between the insertion site and the proximal broken end measured intraoperatively was 4.07 ± 1.57 cm. High or excellent consistencies were found for ATR classifications (kappa: 0.739-0.770, p < 0.001) and rupture sites (ICC: 0.962-0.979, p < 0.001) between two observers and between observers 1 and 2 and intraoperative findings. Tendinopathy was identified in 22 patients by MRI and confirmed during surgery. CONCLUSIONS: MRI scanning of acute closed ATR can help determine whether there is degeneration of the AT, as well as the location and shape of the rupture, which can guide the selection of the optimal operation method for orthopedic surgeons. Therefore, it is necessary to take preoperative MRI scans for patients with acute Achilles tendon ruptures.

Epidemiological Characteristics of Patients Operated for Achilles Tendon Rupture in Shanghai.

OBJECTIVE: To reflect the potential epidemiological characteristics of Achilles tendon (AT) rupture in Shanghai, China, which has been rarely reported before. METHODS: This work is a descriptive epidemiology study. A total of 302 cases of AT rupture admitted to our department between 01/2013 and 02/2020 are analyzed according to telephone follow-up and medical records. Male to female ratio is 10.3 and the average age is 37.5 years. The record of each case includes age, gender, Body mass index (BMI), quinolone use, corticoid exposure and related medical history/comorbidities. If the case is sports-related (SR), details including kind of sports, intensity of exercise, exercise time before rupture, specific action that causes rupture and situation of warm-up are collected. Two independent sample t-tests and Pearson chi-square tests are used for statistical analysis. RESULTS: A total of 252 ruptures are SR. Male to female ratio is 15.6 in SR cases. Most SR ruptures occur in patients aged 25-39 years. Ball games are major sports responsible for rupture: basketball in 95 (37.7%), badminton in 68 (27.0%) and soccer in 62 (24.6%). Acceleration and running start is the specific action that cause most (37.7%) ruptures. AT cases are observed in 91 patients with warm-up and 161 without preparation before exercise. As a result, more ruptures happened within 10 min' sports in 161 unprepared (22.4%) than in 91 prepared (5.5%) cases. In SR cases, 107 and 145 cases are observed on weekends and weekdays. Of the 302 total cases, 64 are associated with Achilles tendinopathy. Frequently reported factors such as quinolone use and corticoid exposure are found only in two and 11 of all cases, respectively. CONCLUSION: Middle-aged males are common victims of AT rupture in Shanghai. Sports including basketball, badminton, soccer and actions involving in sudden and severe contraction of AT cause most ruptures. Warm-up before exercise reduces rupture in short time. Factors such as quinolone, corticoid and Achilles tendonitis still need attention.

Comparison of material properties of heel pad between adults with and without type 2 diabetes history: An in-vivo investigation during gait.

Objective: This study was aimed to compare the material properties of heel pad between diabetes patients and healthy adults, and investigate the impact of compressive loading history and length of diabetes course on the material properties of heel pad. Methods: The dual fluoroscopic imaging system (DFIS) and dynamic foot-ground contact pressure-test plate were used for measuring the material properties, including primary thickness, peak strain, peak stress, stiffness, viscous modulus and energy dissipation ratio (EDR), both at time zero and following continuous loading. Material properties between healthy adults and DM patients were compared both at time zero and following continuous weight bearing. After then, comparison between time-zero material properties and properties following continuous loading was performed to identify the loading history-dependent biomechanical behaviour of heel pad. Subgroup-based sensitivity analysis was then conducted to investigate the diabetes course (<10 years vs. ≥10 years) on the material properties of heel pad. Results: Ten type II DM subjects (20 legs), aged from 59 to 73 (average: 67.8 ± 4.9), and 10 age-matched healthy adults (20 legs), aged from 59 to 72 (average: 64.4 ± 3.4), were enrolled. Diabetes history was demonstrated to be associated with significantly lower primary thickness (t=3.18, p=0.003**), higher peak strain (t=2.41, p=0.021*), lower stiffness (w=283, p=0.024*) and lower viscous modulus (w=331, p<0.001***) at time zero, and significantly lower primary thickness (t=3.30, p=0.002**), higher peak strain (w=120, p=0.031*) and lower viscous modulus (t=3.42, p=0.002**) following continuous loading. The continuous loading was found to be associated with significantly lower primary thickness (paired-w=204, p<0.001***) and viscous modulus (paired-t=5.45, p<0.001***) in healthy adults, and significantly lower primary thickness (paired-w=206, p<0.001***) and viscous modulus (paired-t=7.47, p<0.001***) in diabetes group. No any significant difference was found when conducting the subgroup analysis based on length of diabetes course (<10 years vs. ≥10 years), but the regression analysis showed that the length of diabetes history was positively associated with the peak strain, at time zero (r=0.506, p<0.050) and following continuous loading (r=0.584, p<0.010). Conclusions: Diabetes patients were found to be associated with decreased primary thickness and viscous modulus, and increased peak strain, which may contribute to the vulnerability of heel pad to injury and ulceration. Pre-compression history-dependent behaviour is observable in soft tissue of heel pad, with lowered primary thickness and viscous modulus.

Influence of Achilles tendon rupture site on surgical repair outcomes.

PURPOSE: This study aims to measure the distance between the common site of Achilles tendon rupture and calcaneal insertion through ultrasound and to compare the outcomes between proximal and distal rupture groups. METHODS: We investigated the electronic medical records of 117 patients and preoperative ultrasound describing the rupture site. Among 88 patients, we compared the patient-reported outcome and re-rupture rate of proximal and distal rupture groups. RESULTS: The mean rupture site of the 117 included subjects was 4.5 ± 1.3 cm. The rupture site had a weak negative correlation with body mass index (ρ = -0.230, P = 0.013). Furthermore, 77% of the patients with distal rupture reported good outcome (Achilles Tendon Rupture Score > 80) compared to 56% of the patients with proximal rupture (P = 0.041). CONCLUSION: Patients with proximal rupture had less satisfactory postoperative outcomes than those with distal rupture.

Preparation and antibacterial activity of oligosaccharides derived from dandelion.

In this study, we prepared oligosaccharides from dandelion (Taraxacum officinale) by hydrolysis with hydrogen peroxide (H2O2) and investigated their antibacterial activity. The optimum hydrolysis conditions, as determined using the response surface methodology, were as follows: reaction time, 5.12h; reaction temperature, 65.53 °C and H2O2 concentration, 3.16%. Under these conditions, the maximum yield of the oligosaccharides reached 25.43%. The sugar content in the sample was 96.8%, and the average degree of polymerisation was approximately 9. The oligosaccharides showed high antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus, indicating that dandelion-derived oligosaccharides have the potential to be used as antibacterial agents.

IL-18 levels in the semen of male infertility: semen analysis.

This study investigated the relationship between interleukin (IL)-18 levels and male infertility. Semen samples from 57 infertile and normal males were subjected to semen analysis. The pH of the semen samples from normal and abnormal groups showed no significant difference (p>0.05). However, semen volume, density, forward movement percentage, activity, survival rate, and normal morphology rate of the sperms in the normal group were significantly higher than those of the abnormal group (p<0.01). The IL-18 levels of semen in the abnormal group (810.91 pg/mL) were higher than that of the normal group (402.74 pg/mL; p<0.01). Analyses indicate that seminal fluid IL-18 positively correlates with IL-6, IL-8, and tumor necrosis factor-α. Seminal IL-18 level does not affect bacterial colony count. Results indicate that IL-18 may be important in male reproduction.

Hypolipidemic activity of the polysaccharides from Enteromorpha prolifera.

Enteromorpha prolifera is an edible alga that is used as a traditional herb to treat many diseases. This study prepared E. prolifera polysaccharides (EPPs) and determined their hypolipidaemic activity in rats. Forty-eight male Sprague-Dawley rats were divided into three groups and fed with diets containing either high fat (HF), EPPs or normal fat (NF) for 6 weeks. Compared with the HF group, the EPP group showed decreased body weight gain, plasma triacylglycerol (TG), total cholesterol (TC), plasma low-density lipoprotein cholesterol level, liver TG, liver TC and liver weight. The faecal fat, cholesterol and plasma high-density lipoprotein cholesterol of the EPP group were higher than those of the NF and HF groups. Results suggested that EPPs had a high hypolipidaemic activity and could be a suitable alternative hypolipidaemic source for humans.