scholarly journals METAL-INDUCED PROTEIN DENATURATION: REGULARITIES, PATHOLOGICAL MANIFESTATIONS, AND IN VITRO MODELING

2021 ◽  
Vol 127 (4) ◽  
pp. 48-54
Author(s):  
Tetiana Popovych ◽  
Yaroslav Kizim ◽  
Yaroslav Kizim ◽  
Natalia Obernikhina ◽  
Natalia Voroshylova

the ability of various metal ions to form complexes with proteins leads to the denaturation of the latter and the development of immune response. Such hapten effects cause the well-known phenomenon of nickel-allergic contact dermatitis. No less typical are side effects of gadolinium compounds, that are used as contrasts for magnetic resonance imaging, but cause the development of fibrosis. In both cases an important role belongs to the interaction of metal ions with collagen structures. The aim of our study was to compare in vitro effects of copper and nickel ions on destabilized products of collagen cleavage. Significant difference between these metals in their ability to induce aggregation at close to physiological pH values was shown. The influence on the aggregative process of the acidification of the medium was revealed. It was shown that destabilization of protein structure leads to the formation of highly stabilized β-stacked protein aggregates. Comparison of the obtained experimental data with the  literature ones makes it possible to approach the understanding of individual mechanisms of toxic effects of metal ions on the human body.

2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Xian Xu ◽  
Jingming Gao ◽  
Shuyun Liu ◽  
Liang Chen ◽  
Min Chen ◽  
...  

Abstract With the development of tissue engineering and regenerative medicine, it is much desired to establish bioimaging techniques to monitor the real-time regeneration efficacy in vivo in a non-invasive way. Herein, we tried magnetic resonance imaging (MRI) to evaluate knee cartilage regeneration after implanting a biomaterial scaffold seeded with chondrocytes, namely, matrix-induced autologous chondrocyte implantation (MACI). After summary of the T2 mapping and the T1-related delayed gadolinium-enhanced MRI imaging of cartilage (dGEMRIC) in vitro and in vivo in the literature, these two MRI techniques were tried clinically. In this study, 18 patients were followed up for 1 year. It was found that there was a significant difference between the regeneration site and the neighboring normal site (control), and the difference gradually diminished with regeneration time up to 1 year according to both the quantitative T1 and T2 MRI methods. We further established the correlation between the quantitative evaluation of MRI and the clinical Lysholm scores for the first time. Hence, the MRI technique was confirmed to be a feasible semi-quantitative yet non-invasive way to evaluate the in vivo regeneration of knee articular cartilage.


2021 ◽  
Vol 20 (2) ◽  
Author(s):  
Siti Hajjar Nasir ◽  
Muhammad Syahmi Mohamad Amran ◽  
Muhammad Muaz Abidin Mustaffar

INTRODUCTION: The growing demand for orthodontic braces among Malaysians has led to the development of fake braces. These fake braces services are illegal and their brackets are reported to be of inferior quality. Fake braces are constantly being exposed to the saliva intraorally, hence they are susceptible to corrosion. This study was conducted to investigate the release of metal ions as a result of corrosion from standard and fake orthodontic braces immersed in artificial saliva of different pH. MATERIALS AND METHODS: A total of six different types of brackets (three from standard and three from fake braces) were immersed in containers containing 5 mL of artificial saliva of pH 4.9 and pH 7.8. The samples were collected for analysis on day 1, day 14, and day 28 using Inductively-Coupled Plasma Mass Spectrometry (ICPMS) to evaluate the amount of metal ion released. Statistical analysis was performed to isolate the significant difference of metal ions released between two types of braces in different pH solutions. RESULTS: The release of aluminum, nickel, chromium, manganese and copper were observed and analyzed. Fake braces released the highest concentration of chromium, manganese, and nickel ions in both artificial saliva as compared to standard braces. Brackets immersed in pH 4.9 released a higher number of ions compared to pH 7.8. CONCLUSION: This study showed that fake braces released the highest concentration of metal ions as compared to standard braces. Both time and pH influenced the release of metal ions from orthodontic brackets.


1991 ◽  
Vol 65 (05) ◽  
pp. 549-552 ◽  
Author(s):  
A Blinc ◽  
G Planinšič ◽  
D Keber ◽  
O Jarh ◽  
G Lahajnar ◽  
...  

SummaryMagnetic resonance imaging was employed to study the dependence of clot lysing patterns on two different modes of transport of urokinase into whole blood clots. In one group of clots (nonperfused clots, n1 = 10), access of urokinase to the fibrin network was possible by diffusion only, whereas in the other group (perfused clots, n2 = 10) bulk flow of plasma containing urokinase was instituted through occlusive clots by a pressure difference of 3 .7 kPa (37 cm H2O) across 3 cm long clots with a diameter of 4 mm. It was determined separately that this pressure difference resulted in a volume flow rate of 5.05 ± 2.4 × 10−2 ml/min through occlusive clots. Perfused clots diminished in size significantly in comparison to nonperfused ones already after 20 min (p <0.005). Linear regression analysis of two-dimensional clot sizes measured by MRI showed that the rate of lysis was more than 50-times faster in the perfused group in comparison to the nonperfused group. It was concluded that penetration of the thrombolytic agent into clots by perfusion is much more effective than by diffusion. Our results might have some implications for understanding the differences in lysis of arterial and venous thrombi.


2016 ◽  
Vol 13 (7) ◽  
pp. 697-705 ◽  
Author(s):  
Chen Zhu ◽  
Xiao Enhua ◽  
Shang Quanliang ◽  
Kang Zhen ◽  
Tan Huilong ◽  
...  

2021 ◽  
Vol 315 ◽  
pp. 110900
Author(s):  
Jiaqi Hu ◽  
Yi Chen ◽  
Hui Zhang ◽  
Zhenxia Chen ◽  
Yun Ling ◽  
...  

Author(s):  
Eisha Imran ◽  
Faisal Moeen ◽  
Beenish Abbas ◽  
Bakhtawar Yaqoob ◽  
Mehreen Wajahat ◽  
...  

Abstract Objectives The study aimed to evaluate and compare various commercially available local anesthetic solutions. Materials and Methods A total of 150 commercially available local anesthetic cartridges of similar composition (2% lidocaine with epinephrine 1:100,000) were randomly collected and divided into 3 groups. The designations of groups were selected from their product names such that each group consisted of 60 cartridges. Group S (Septodont, France) Group M (Medicaine, Korea) and Group H (HD-Caine, Pakistan). The samples were divided into five sub-groups, each consisting of 10 cartridges from each group to investigate each parameter. Results The acquired data was statistically analyzed and compared (using SPSS version 12). Compositional analysis revealed a non-significant (P>0.05) difference when the three Groups were compared with standard lidocaine and epinephrine solutions. The mean pH values of samples from group S, M and H respectively fell within the range of pH values of commercially available solutions. Non-significant difference in EPT values of Group S and H was found when efficacy was compared (p = 0.3), however a significant difference (p < 0.01) was observed in contrast to Group M. Anti-bacterial activity was observed in all the group and a non-significant difference in cell viability values of Group S and M was found (p = 0.6), while the difference was significant in comparison to Group H. Conclusion Within the limitations of these investigations, it appears that the properties of different manufacturers fall within the recommended ranges as mentioned in literature and do not appear to be statistically different in the variables we have tested.


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