tissue resistance
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2022 ◽  
Vol 11 (1) ◽  
pp. e35411124606
Author(s):  
Mellânia Rodrigues Goveia ◽  
Gleyson Murillo Aguilera Moraes ◽  
Marco Antônio de Souza Borges Tavares ◽  
Tauanne Fernanda dos Santos ◽  
Lanúbia Garcia de Araújo Vasconcelos ◽  
...  

Osteoporosis is a condition characterized by deterioration of bone microarchitecture resulting in loss of total bone mass, decreased tissue resistance and increased susceptibility to fractures. The study in question aimed to analyze and debate the risk factors and the effectiveness of forms of prevention related to osteoporosis, given their implication for the general population and the need to disseminate safe and effective forms of behavioral management that can contribute to the decrease in the condition, mainly in the most susceptible individual. For this, 42 articles indexed in Bireme, PubMed, Scielo and UpToDate platforms were selected for discussion of the topic. Thus, it was concluded that the need for active investigation of risk factors by health professionals, as well as the encouragement of preventive practices, especially in the population with higher incidence of the disease.


2021 ◽  
Vol 2086 (1) ◽  
pp. 012106
Author(s):  
V V Antipenko ◽  
E A Pecherskaya ◽  
S A Antipenko ◽  
O A Timokhina ◽  
D V Artamonov ◽  
...  

Abstract Radiofrequency ablation (RFA) is used to treat both congenital and acquired heart diseases, including arrhythmias of various types. In this work, experimental studies are carried out on biological tissues under the influence of the applied power on the tissue. Based on the experiments carried out, it was concluded that the effectiveness of the effect on biological tissue and the quality of the result obtained clearly depend on the correct choice of power applied to the treated tissue.


2021 ◽  
Vol 57 (5) ◽  
pp. 78-87
Author(s):  
I.V. Yudaev ◽  
◽  
Yu.V. Daus ◽  

Currently, in order to obtain pre-planned results and increase the efficiency of using existing technologies, electrotechnological operations are applied in the processes of agricultural production, food and processing industries, including those that implement the effects of high voltage impulses. One of such promising technologies in agriculture can be considered to be electric impulse weeding that is the fight against unwanted and weed vegetation. Such operation, which is carried out with high rates of technological efficiency, is environmentally friendly and refers to high-tech processes. For practical applications and technical implementations, it is necessary to study various properties and parameters of effected objects – weeds. The partial dependence of the electrical resistance of the plant tissue or the dispersion of resistance over the frequency of the measuring current was decided to be used as the studied characteristic. This approach allows to consider weeds not only as a load with which the electrical energy supply system is in contact but also to thoroughly study how this resistance changes during processing. The conducted experimental studies made it possible to clarify the nature of the change in resistance under the damage process to plant tissue, as well as to estimate the quantitative indicators of both the energy absorbed by the plant tissue and the ranges of variations of its resistance. The change character in the plant tissue resistance at the process of the electrical impulse damage remains unchanged, only the resistance value at low frequencies decreases. The total damage corresponds to the period of processing when the resistance of the plant tissue is practically equal at low and high frequencies. This behavior of the mentioned parameter is typical for internal and surface tissues of weeds, as well as for their root systems and leaf-stem parts. Theoretical verification of the change character in the plant tissue resistance of destroyed weeds confirmed the description of the proposed mechanism of change in resistance in the process of irreversible electrical impulse damage.


2021 ◽  
pp. 1-11
Author(s):  
Elise E. Crame ◽  
Joanne M. Bowen ◽  
Kate R. Secombe ◽  
Janet K. Coller ◽  
Maxime François ◽  
...  

<b><i>Introduction:</i></b> Toll-like receptor 4 (TLR4) is a highly conserved immunosurveillance protein of innate immunity, displaying well-established roles in homeostasis and intestinal inflammation. Current evidence shows complex relationships between TLR4 activation, maintenance of health, and disease progression; however, it commonly overlooks the importance of site-specific TLR4 expression. This omission has the potential to influence translation of results as previous evidence shows the differing and distinct roles that TLR4 exhibits are dependent on its spatiotemporal expression. <b><i>Methods:</i></b> An intestinal epithelial TLR4 conditional knockout (KO) mouse line (<i>Tlr4</i><sup><i>ΔIEC</i></sup>, <i>n</i> = 6–8) was utilized to dissect the contribution of epithelial TLR4 expression to intestinal homeostasis with comparisons to wild-type (WT) (<i>n</i> = 5–7) counterparts. Functions of the intestinal barrier in the ileum and colon were assessed with tissue resistance in Ussing chambers. Molecular and structural comparisons in the ileum and colon were assessed via histological staining, expression of tight junction proteins (occludin and zonular occludin 1 [ZO-1]), and presence of CD11b-positive immune cells. <b><i>Results:</i></b> There was no impact of the intestinal epithelial TLR4 KO, with no differences in (1) tissue resistance–ileum (mean ± standard error of mean [SEM]): WT 22 ± 7.2 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 20 ± 5.6 (Ω × cm<sup>2</sup>) <i>p</i> = 0.831, colon WT 30.8 ± 3.6 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 45.1 ± 9.5 <i>p</i> = 0.191; (2) histological staining (overall tissue structure); and (3) tight junction protein expression (% area stain, mean ± SEM)–ZO-1: ileum–WT 1.49 ± 0.155 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 1.17 ± 0.07, <i>p</i> = 0.09; colon–WT 1.36 ± 0.26 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 1.12 ± 0.18 <i>p</i> = 0.47; occludin: ileum–WT 1.07 ± 0.12 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 0.95 ± 0.13, <i>p</i> = 0.53; colon–WT 1.26 ± 0.26 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 1.02 ± 0.16 <i>p</i> = 0.45. CD11b-positive immune cells (% area stain, mean ± SEM) in the ileum were mildly decreased in WT mice: WT 0.14 ± 0.02 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 0.09 ± 0.01 <i>p</i> = 0.04. However, in the colon, there was no difference in CD11b-positive immune cells between strains: WT 0.53 ± 0.08 versus <i>Tlr4</i><sup><i>ΔIEC</i></sup> 0.49 ± 0.08 <i>p</i> = 0.73. <b><i>Conclusions:</i></b> These data have 2 important implications. First, these data refute the assumption that epithelial TLR4 exerts physiological control of intestinal physiology and immunity in health. Second, and most importantly, these data support the use of the <i>Tlr4</i><sup><i>ΔIEC</i></sup> line in future models interrogating health and disease, confirming no confounding effects of genetic manipulation.


Author(s):  
Lean Heong Foo

AbstractGuided tissue regeneration (GTR) has been proven to promote attachment and regeneration of periodontal tissue. However, there is a 20 to 40% incidence of attachment loss on regenerated attachments reported in the literature. To my knowledge, this is the first case report on a second attempt in GTR on a previous successful grafted site with clinical attachment loss. A healthy 17-year-old Chinese male patient had GTR performed with xenograft particles and bovine resorbable membrane on his root-canal treated, fused upper right lateral incisor and upper right canine (#12-#13) in 2007. Probing depth on the mid-palatal region of #12-#13 was reduced to 4 mm and maintained for the next 4 years. But in the fifth year, probing depth increased to 11 mm with no endodontic symptoms, and a second attempt of GTR using the same materials was carried out. The probing depth at the surgical site was reduced to 4 mm and successfully maintained for another 5 years. Irregular maintenance and the presence of plaque retentive factor could have caused the clinical attachment loss on #12-#13. This case shows it is possible to attempt GTR on a previous successfully grafted site. GTR did not increase tissue resistance against periodontal breakdown. Hence, proper maintenance planning for GTR sites is important to prevent periodontal breakdown.


2021 ◽  
Vol 6 (1) ◽  
pp. 60-68
Author(s):  
V. I. Kostin ◽  
O. A. Shangina ◽  
V. G. Shelikhov

Over the past few decades, various applications of the metabolic drugs have been extensively tested. Most of them affect oxygen-dependent processes, improving cellular metabolism and increasing tissue resistance to hypoxia and ischemia. The most promising candidates include components of the respiratory chain, purine nucleosides, and creatine phosphate which affect glucose oxidation and fatty acid metabolism in the Krebs cycle. This review critically evaluates the most popular drugs of this group (adenosine triphosphate, adenosine-5-monophosphate, creatine phosphate, coenzyme Q10, cytochrome C, adenosine, glucose-insulin-potassium solution, L-carnitine, mildronate, and trimetazidine), which are widely represented on the pharmaceutical market. Of all metabolic drugs, only trimetazidine was included in the European and Russian recommendations for the second-line treatment of stable angina. In most clinical studies, the therapeutic efficacy of metabolic drugs has been evaluated using the surrogate endpoints. Despite being actively advertised and widely used in the clinical practice, metabolic drugs currently do not have a convincing evidence base for affecting prognosis (mortality and/or major adverse cardiovascular events). Further studies in large-scale randomised trials are needed to confirm the beneficial effects of the metabolic drugs in cardiovascular medicine.


2021 ◽  
Author(s):  
Maysa Brandao Rangel ◽  
Renilson Moraes-Ferreira ◽  
Manoel Oliveira-Junior ◽  
Alana Santos-Dias ◽  
André Bachi ◽  
...  

Abstract Low-grade inflammation associated with metabolic syndrome (MS) triggers alterations in several organs, but its effects on pulmonary functional and immunological response in older adults are unknown. This cross-sectional study investigated such responses in older adults with and without MS. The study consisted of 77 older adults with MS (68 ± 3 years old) and without MS (67 ± 3 years old). Impulse oscillometry (IOS) was used to evaluate airway and tissue resistance and reactance. Biomarkers of systemic and pulmonary inflammation and fibrosis were studied. Total resistance of respiratory system (R5Hz; p < 0.009), and resistance of proximal (R20Hz; p < 0.001) and distal (R5Hz-R20Hz; p < 0.004) airways were impaired in MS individuals compared to those without MS. The levels of pro-inflammatory (leptin; IL-1beta; IL-8, p < 0.001; TNF-alpha, p < 0.04) and pro-fibrotic (VEGF, p < 0.001) factor increased in MS, while reduced levels of anti-inflammatory cytokines (adiponectin; IL-1ra; IL-10; p < 0.001), and anti-fibrotic (relaxin 1; relaxin 3; Klotho, p < 0.001) factors were found. We conclude that MS accelerates lung function and mechanics impairment in older adults in detriment of an imbalance between pro and anti-inflammatory and fibrotic mediators. Furthermore, this study shows that the lungs also are a target organ in MS, deserving clinical assessment in older adults’ population.


2021 ◽  
Vol 17 (1) ◽  
pp. e1008632
Author(s):  
Martina Conte ◽  
Sergio Casas-Tintò ◽  
Juan Soler

Glioblastoma is the most aggressive tumor of the central nervous system, due to its great infiltration capacity. Understanding the mechanisms that regulate the Glioblastoma invasion front is a major challenge with preeminent potential clinical relevances. In the infiltration front, the key features of tumor dynamics relate to biochemical and biomechanical aspects, which result in the extension of cellular protrusions known as tumor microtubes. The coordination of metalloproteases expression, extracellular matrix degradation, and integrin activity emerges as a leading mechanism that facilitates Glioblastoma expansion and infiltration in uncontaminated brain regions. We propose a novel multidisciplinary approach, based on in vivo experiments in Drosophila and mathematical models, that describes the dynamics of active and inactive integrins in relation to matrix metalloprotease concentration and tumor density at the Glioblastoma invasion front. The mathematical model is based on a non-linear system of evolution equations in which the mechanisms leading chemotaxis, haptotaxis, and front dynamics compete with the movement induced by the saturated flux in porous media. This approach is able to capture the relative influences of the involved agents and reproduce the formation of patterns, which drive tumor front evolution. These patterns have the value of providing biomarker information that is related to the direction of the dynamical evolution of the front and based on static measures of proteins in several tumor samples. Furthermore, we consider in our model biomechanical elements, like the tissue porosity, as indicators of the healthy tissue resistance to tumor progression.


2021 ◽  
Vol 3 (2) ◽  
pp. 765-771
Author(s):  
Yuuki Matsui ◽  
Sena Iguchi ◽  
Emiri Sato ◽  
Yoichiro Sato ◽  
Ken Shindo ◽  
...  

AbstractGunshot injuries involving the head and neck region yield profound morbidity and mortality rates. Projectile-related factors comprising various physical and dynamic properties of a bullet, as well as tissue-related factors, determine the disruptive effects of projectiles on living tissues. We experienced an extremely unusual case of a gunshot injury to the neck, wherein the bullet transversely penetrated across the deep neck structures to the contralateral side of the shoulder without damaging any vital organs. A 51-year-old man presented with a gunshot wound to the neck from a point-blank range. A bullet entry hole was observed on the left side of the neck without an exit hole; however, the patient was conscious, vital signs were normal, and no active bleeding, cranial nerve palsy, or aero-digestive tract injury was found. Imaging tests revealed a bullet lying in front of the right humeral head, which was extracted by emergency surgery. The patient was uneventfully discharged. According to the localization of the damaged tissues and the positional relationship between the bullet’s entrance and its destination, the bullet was estimated to have nonlinearly traversed the neck by traveling through the interstructural spaces associated with the least tissue resistance. Our experience strongly suggests the importance of realizing the unpredictable nature of a bullet trajectory in a body. An appropriate understanding of various ballistic factors and wounding mechanisms can be of great help in the adequate assessment and management of patients with gunshot injuries.


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