Biophysical and Biomechanical Effect of Low Intensity US Treatments on Pancreatic Adenocarcinoma 3D Cultures

Current developments in medical technology have focused on therapeutic treatments that selectively and effectively address specific pathological areas, minimizing side effects on healthy tissues. In this regard, many procedures have been developed to provide non-invasive therapy, for example therapeutic ultrasound (US). In the medical field, in particular in cancer research, it has been observed how ultrasounds can cause cell death and inhibit cell proliferation of cancer cells, while preserving healthy ones with almost negligible side effects. Various studies have shown that low intensity pulse ultrasound (LIPUS) and low intensity continuous ultrasound (LICUS) regulate the proliferation, cell differentiation and cavitation phenomena. Nowadays, there are poorly known aspects of low intensity US treatment, in terms of biophysical and biomechanical effects on target cells. The aim of this study is to set up an innovative apparatus for US treatment of pancreatic ductal adenocarcinoma (PDAC) cells, monitoring parameters such as acoustic intensity, acoustic pressure, stimulation frequency and treatment protocol. To this purpose, we have developed a custom-made set up for the US stimulation at 1.2 and 3 MHz of tridimensional (3D) cultures of PDAC cells (PANC-1, Mia Paca-2 and BxPc3 cells). Images of the 3D cultures were acquired, and the Calcein/PI assay was applied to detect US-induced cell death. Overall, the setup we have presented paves the way to an innovative protocol for tumor treatment. The system can be used either alone or in combination with small molecules or recombinant antibodies in order to propose a novel combined therapeutic approach.

The Effect of Functional Biomechanics Garment for Walking

The purpose of this study was to investigate the effects of a functional biomechanics garment (FBG) with a lower extremity assist function. 32 healthy male participants were included in this study. Participants were divided into an FBG with taping function group (FBG group) and a compression garment group (CG group). Cadence (steps/min), step length (m), and usual walking speed (m/s) were measured as spatio-temporal data. Kinetics, kinematics data, and dynamic joint stiffness (DJS) of the lower extremity were calculated using a three-dimensional gait analysis system. The FBG group showed significantly faster walking speed (FBG, 1.54 ± 0.12 m/s; CG, 1.42 ± 0.15 m/s, p < 0.05) and reduced hip DJS in terminal stance (FBG, 0.033 ± 0.014 Nm/kg/degree; CG: 0.049 ± 0.016 Nm/kg/degree, p < 0.05) compared to the CG group. The FBG decreased hip DJS in the terminal stance and affected walking speed. The passive elastic moment generated by the high elasticity part of the hip joint front in the FBG supported the internal hip flexion moment. Therefore, our FBG has a biomechanical effect. The FBG may be useful as a tool to promote health activities.

Biomechanical Analysis of Clavicle Hook Plates with a Range of Posterior Hook Offsets Implanted at Different Acromion Positions in the Acromioclavicular Joint: A Finite Element Analysis Study

The clavicle hook plate is commonly used in acromioclavicular injuries; however, the biomechanical effect of the posterior hook offset and hook position is unclear. This study applied a finite element analysis (FEA) to evaluate these parameters to improve the clinical strategy. Nine FEA models with 0-mm, 5-mm, and 10-mm posterior hook offsets implanted in the anterior, middle, and posterior acromion were established to evaluate the stress distribution and the reaction force on the acromion. The 5-mm and 10-mm posterior hook offsets at all acromion positions reduced the reaction force on the acromion but slightly increased the stress on the clavicle. The 0-mm offset increased the reaction force at all acromion positions and was relatively lower at the middle acromion. The clavicle hook plate with a posterior hook offset reduces the reaction force on the acromion, providing a flexibility of the hook position. These results provide surgeons with the biomechanical basis for the hook offset and position and engineers with the mechanical basis for the implant design.

Is a Parry Fracture—An Isolated Fracture of the Ulnar Shaft—Associated with the Probability of Abuse in Children between 2 and 16 Years Old?

A parry fracture is an isolated fracture of the ulnar shaft. It occurs when the ulna receives the full force of an impact when the forearm is raised to protect the face. The aim of this study is to assess a possible association between a parry fracture and the probability of abuse in children. In this retrospective, observational, multicenter study, we identified patients between 2 and 16 years old who had been treated for an isolated ulnar shaft fracture. Patient characteristics were registered, anonymized radiographs were rated, and charts were screened for referral to a child protective team. A total of 36 patients were analyzed. As no referrals were registered during follow-up, the primary outcome was changed to a perpendicular force as trauma mechanism. Univariable regression analysis and independent t-test both showed no significant association between patient factors or radiographic classification, and the reported trauma mechanism. We were unable to determine an association between a parry fracture and the probability of abuse. Since trauma mechanism does have a biomechanical effect on the fracture type, we would advise that a very clear reconstruction (and documentation) of the trauma mechanism should be established when a parry fracture is identified on radiographs.

Biomechanical Effect of Orthodontic Treatment of Canine Retraction by Using Metallic Orthodontic Mini-Implant (OMI) Covered with Various Angles of Revolving Cap

Objective. This study evaluated the biomechanical effects of a metallic orthodontic mini-implant (OMI) covered with various types of angled revolving cap on the peri-OMI bone and the canine periodontal ligament (PDL) by finite element (FE) analyses. Materials and Methods. Three-dimensional FE models included comprised cortical bone and cancellous bone of the maxilla, and the OMIs were created. The forces (0.98 N) pulled in both the canine hook and the revolving cap, pulling towards each other in both directions as loading conditions. The upper surface of the maxilla was fixed as a boundary condition. Results. The bone stresses were increasing in the models by using OMI covered with a revolving cap as compared with that in the conventional model (in which only the OMI was placed). However, no obvious differences in bone stresses were observed among the models with various types of angled revolving cap. The minimum principal strain in the canine PDL was highest for condition 180T, followed by condition 180L. However, the maximum differences in the values between each experimental model and the conventional model were around 5%. Conclusion. This study showed no obvious effects in decreasing or increasing stress/strain in bone and PDL by using various types of angled revolving cap covered metallic mini-implant in orthodontic treatment of canine retraction.

The biomechanical effect on the adjacent L4/L5 segment of S1 superior facet arthroplasty: a finite element analysis for the male spine

Background The superior facet arthroplasty is important for intervertebral foramen microscopy. To our knowledge, there is no study about the postoperative biomechanics of adjacent L4/L5 segments after different methods of S1 superior facet arthroplasty. To evaluate the effect of S1 superior facet arthroplasty on lumbar range of motion and disc stress of adjacent segment (L4/L5) under the intervertebral foraminoplasty. Methods Eight finite element models (FEMs) of lumbosacral vertebrae (L4/S) had been established and validated. The S1 superior facet arthroplasty was simulated with different methods. Then, the models were imported into Nastran software after optimization; 500 N preload was imposed on the L4 superior endplate, and 10 N⋅m was given to simulate flexion, extension, lateral flexion and rotation. The range of motion (ROM) and intervertebral disc stress of the L4-L5 spine were recorded. Results The ROM and disc stress of L4/L5 increased with the increasing of the proportions of S1 superior facet arthroplasty. Compared with the normal model, the ROM of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 2/5 from the apex to the base. The disc stress of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 1/5 from the apex to the base. Conclusion In this study, the ROM and disc stress of L4/L5 were affected by the unilateral S1 superior facet arthroplasty. It is suggested that the forming range from the ventral to the dorsal should be less than 3/5 of the S1 upper facet joint. It is not recommended to form from apex to base. Level of evidence Level IV