It is now well established that the mechanical environment of the cells in tissues deeply impacts cellular fate, including life cycle, differentiation and tumor progression. Designs of biomaterials already include the control of mechanical parameters, and in general, their main focus is to control the rheological properties of the biomaterials at a macroscopic scale. However, recent studies have demonstrated that cells can stress their environment below the micron scale, and therefore could possibly respond to the rheological properties of their environment at this micron scale. In this context, probing the mechanical properties of physiological cellular environments at subcellular scales is becoming critical. To this aim, we performed in vitro indentation measurements using AFM on sliced human pituitary gland tissues. A robust methodology was implemented using elasto-adhesive models, which shows that accounting for the adhesion of the probe on the tissue is critical for the reliability of the measurement. In addition to quantifying for the first time the rigidity of normal pituitary gland tissue, with a geometric mean of 9.5 kPa, our measurements demonstrated that the mechanical properties of this tissue are far from uniform at subcellular scales. Gradients of rigidity as large as 12 kPa μm(-1) were observed. This observation suggests that physiological rigidity can be highly non-uniform at the micron-scale.

While technical problems of tracheobronchial reconstruction in our series were controllable, the long-term results were not satisfying. Our data suggest that the key for better outcome of these kind of lesions lies in an early diagnosis and immediate treatment, thus keeping the trauma-treatment interval with the concomitant hypoxic damage as short as possible.

Study Design: Observational study.Purpose: The actual sanitary crisis led to a massive mobilization of the sanitary system toward intensive care units and management of coronavirus disease 2019 (COVID-19) patients. However, some patients still require spinal interventions. The present study aimed to assess the impact of the COVID-19 pandemic on spine surgical in a moderate COVID-19 cluster region.Overview of Literature: Previous studies have reported screening and management of patients with spinal conditions during the COVID-19 pandemic. However, to date, knowledge, no observational study on spine surgeries during the pandemic has not been reported.Methods: Between March 17, 2020 and April 17, 2020, information on spine surgical activity was prospectively collected at our institution. This surgical activity related to the first month of confinement in France was compared to the activity during the same period in 2019 to evaluate the impact of the COVID-19 pandemic on surgical activities.Results: In order to reduce the contamination rate of patients and medical staff during hospitalization, the spine department was completely reorganized. Non-urgent elective spine surgeries were cancelled. When considering the global amount of surgeries procedures during the first month of confinement, a decrease of almost 50% was observed in the number of surgical procedures. During the study period, 62 patients were eligible for spine surgery. The numbers of patients managed for tumor and infectious cases were stable, while a considerable reduction was observed in the number of trauma and degenerative cases. During the follow-up period, two patients were tested as COVID+ during the postoperative course, and no cases of medical or paramedical staff contamination were reported using polymerase chain reaction-testing.Conclusions: During the COVID-19 pandemic, it is possible to maintain spine surgical activity. Each surgical procedure must be discussed and organized with all the caregivers involved. Indications for surgery must be in line with the scientific guidelines and adapted to each healthcare facility.