Mesenchymal Stem Cell Mechanisms of Action and Clinical Effects in Osteoarthritis: A Narrative Review.

With the insufficient satisfaction rates and high cost of operative treatment for osteoarthritis (OA), alternatives have been sought. Furthermore, the inability of current medications to arrest disease progression has led to rapidly growing clinical research relating to mesenchymal stem cells (MSCs). The availability and function of MSCs vary according to tissue source. The three primary sources include the placenta, bone marrow, and adipose tissue, all of which offer excellent safety profiles. The primary mechanisms of action are trophic and immunomodulatory effects, which prevent the further degradation of joints. However, the function and degree to which benefits are observed vary significantly based on the exosomes secreted by MSCs. Paracrine and autocrine mechanisms prevent cell apoptosis and tissue fibrosis, initiate angiogenesis, and stimulate mitosis via growth factors. MSCs have even been shown to exhibit antimicrobial effects. Clinical results incorporating clinical scores and objective radiological imaging have been promising, but a lack of standardization in isolating MSCs prevents their incorporation in current guidelines.

Characterisation of tree vibrations based on the model of orthogonal oscillations.

This study presents quantitative and qualitative insights into the analysis of data obtained by tracking the motion of reflective markers arranged along the trunk of a pole-like potted tree, which was recorded by a state-of-the-art infrared motion-tracking system. The experimental results showed in-plane damped trajectories of the markers with lateral displacements, i.e. out-of-plane vibrations of the tree under consideration. To explain such response and to determine the corresponding oscillatory characteristics, a completely new and original utilisation of the recorded in-plane damped trajectories is presented. The quantitative insight gained is based on the mechanical model that consists of two orthogonal springs and dampers placed in the plane where the motion takes place, and it is then directed towards the determination of the characteristics of the related orthogonal oscillations: two natural frequencies, the position of the principal axes to which they correspond, and two damping ratios. The qualitative insight gained involves analysing the shape and narrowness of the trajectory to assess how close-valued two natural frequencies are, and how small the overall damping is. The quantitative and qualitative methodologies presented herein are seen as beneficial for arboriculture, forestry and botany, but given the fact that orthogonal oscillations appears in many natural and engineering systems, they are also expected to be useful for specialists in other fields of science and engineering as well.

Sympodial tree-like structures: from small to large-amplitude vibrations.

This study deals with tree-like structures that mimic a trunk with either first-order branches or both first and second-order branches of a sympodial tree. The corresponding mechanical model comprises physical pendula coupled with torsional springs and viscous dampers. Natural frequencies and modal shapes are obtained analytically and the effects of a branching angle and a stiffness ratio on their change is analysed. Then, the trunk is harmonically excited and the corresponding structural response is investigated, both for small undamped and damped vibrations, focusing on the concept of dynamic absorbers and the attenuation of the amplitude of the trunk and first-order branches as this attenuation is beneficial for practical engineering applications. The corresponding frequencies at which these amplitudes are equal to zero or in resonance are determined. Finally, free large-amplitude vibrations are examined. Conditions for internal resonances in the structure with first-order branching are determined analytically by using the method of multiple scales. Frequency spectra of large-amplitude vibrations are obtained numerically focusing on the influence of the branching angle on their content. Biomimetic potentials and advantages of designing these coupled branched structures are discussed through the whole study via the influence of the stiffness ratio of the springs, the branching angle and the hierarchy of branches on their response.

[PREDICTORS OF POOR BOWEL PREPARATION FOR COLONOSCOPY: A SINGLE-CENTRE PROSPECTIVE STUDY]. / PRETKAZATELJI LOSE PRIPREME BOLESNIKA ZA KOLONOSKOPIJU: MONOCENTRICNO PROSPEKTIVNO ISPITIVANJE.

Adequate bowel preparation is the key of a successful colonoscopy. The aim of the study was to analyze sociodemographic and clinical characteristics in our population of patients referred for colonoscopy. Bowel cleanness was evaluated using the Boston Bowel Preparation Scale (BBPS) where values 7 were considered a criterion of successful bowel preparation. The study involved 286 subjects (61.5% male, median 61 years, interquartile range 50-71). BBPS score 7 was found in 145 subjects (50.7%). Multivariate analysis indicated that subjects with severe comorbidity (ASA status 3, OR = 0,29; 95% CI: 0.12-0.72; p = 0,008) represented a risk factor for poor bowel preparation. Regimens with polyethyleneglycol (PEG) were superior compared with other protocols (OR = 2.54; 95% CI: 1.27-5.10; p = 0.008). Timing of the colonoscopy also contributed to better bowel preparation (OR = 5.50; 95% CI: 2.07-14.67; p = 0.001). This study confirms that presence of comorbidity and non-use of PEG regimens are predictors of poor bowel preparation in our population of patients referred for colonoscopy.