Atherosclerotic plaque rupture is the main cause of many cardiovascular diseases, and biomechanical factors play an important role in the process of plaque rupture. In the study of plaque biomechanics, there are relatively few studies based on fatigue fracture failure theory, and most of them mainly focus on the whole fatigue propagation process from crack initiation to plaque rupture, while there are few studies on the influence of crack on plaque rupture at a certain time in the process of fatigue propagation. In this paper, a two-dimensional plaque model with crack was established. Based on the theory of fracture mechanics and combined with the finite element numerical simulation method, the stress intensity factor (SIF) and related influencing factors at the crack tip in the plaque were studied. The SIF was used to measure the influence of crack on plaque rupture. The results show that the existence of crack can lead to local stress concentration, which increases the risk of plaque rupture. The SIF at the crack tip in the plaque was positively correlated with blood pressure, but negatively correlated with fibrous cap thickness and lipid pool stiffness. The effect of the thickness and angle of lipid pool on the SIF at the crack tip in the plaque was less than 4%, which could be ignored. This study provides a theoretical basis for the risk assessment of plaque rupture with cracks.
【摘要】 目的 探讨血尿酸水平、颈动脉斑块与冠心病之间的关系。 方法 收集2006年1月-2009年12月拟诊为冠心病的住院患者280例,冠状动脉造影检查冠状动脉狭窄程度gt;50%的194例为冠心病组,冠状动脉无狭窄或狭窄程度lt;50%的86例为对照组;冠心病组又分为单支、双支、多支病变亚组。分别测定冠心病组与对照组颈总动脉与颈动脉分叉处内膜中层厚度(IMT)、等级评分、Crouse积分、血尿酸浓度。结果 与对照组相比,冠心病组颈总动脉与颈动脉分叉处IMT、等级评分、Crouse积分、血尿酸浓度均高于对照组,差异有统计学意义。在冠心病组,随病变分支的增多,颈动脉超声检查指标与血尿酸随之升高(Plt;0.05或0.01)。 结论 颈动脉IMT、等级评分、Crouse积分、血尿酸浓度与冠心病相关,是冠心病的独立危险因素。【Abstract】 Objective To investigate the relationships between serum uric acid levels, carotid artery plaque and coronary heart disease (CHD). Methods 194 patients with CHD and 86 nonCHD patients were selected through coronary angiography in patients with essential hypertension. CHD group was divided into three subgroups including a single branch, doublebranch and multivessel disease. Intimamedia thickness (IMT) of carotid artery and carotid bifurcation, grade score, Crouse score, serum uric acid concentrations were detected in patients with coronary heart disease and control group. Results IMT of carotid artery and carotid bifurcation, grade score,crouse score, serum uric acid concentrations were higher in CHD group than that in control group, and the difference was statistically significant. In the CHD group, ultrasound parameters of carotid artery and serum uric acid increased with the increase in branch lesions (Plt;005 or 001). Conclusions Carotid IMT, grade score, Crouse score, serum uric acid concentration relate to coronary heart disease, which is an independent risk factor for coronary heart disease, respectively.
A method of ultrasonic simulation based on the FIELD II software platform for carotid artery plaque was proposed according to the analysis for geometrical shape, tissue characteristics and acoustic properties of carotid artery plaques in clinic, and then a simulation system was developed by using the MATLAB graphical user interface (GUI). In the simulation and development, a three-dimensional geometric model of blood vessel with plaques was set up by using the metaball implicit surface technique, and a tissue model was established based on the scatterers with spatial position of gamma random distribution. Comparison of the statistical and geometrical characteristics from simulated ultrasound B-mode images with those based on clinical ones and preset values, the results fully demonstrated the effectiveness of the simulation methods and system.
The present paper intends to discuss the antioxidant and tyrosinase inhibition effect of solanesol from three aspects of ultraviolet radiation and free radical scavenging. The paper makes a survey on diurnal variation rule of the minimum ultraviolet transmittance and ultraviolet transmittance of solanesol, hydroxyl (·OH) free radical scavenging method of Smirnoff reaction system model, superoxide anion O2-· free radical scavenging method of pyrogallol autoxidation, and the inhibitory effect of solanesol on tyrosinase activity by enzyme kinetic method. The experiment results showed that solanesol could effectively scavenge lipid radicals to block lipid peroxidation, and inhibit effects on tyrosinase. Solanesol is a natural extract which could be used to prevent senile atrophy of human skin and senile plaque.
ObjectiveTo systematically review the long-term efficacy of biologics for moderate to severe plaque psoriasis. MethodsPubMed, EMbase, Web of Science and The Cochrane Library were electronically searched to collect randomized controlled trials (RCTs) on the long-term efficacy of approved biologics for moderate to severe plaque psoriasis from inception to May 2021. Two reviewers independently screened the literature, extracted data and assessed the risk of bias of the included studies; then, the network meta-analysis was performed by using Stata 16.0 software. ResultsA total of 26 RCTs were included. The results of network meta-analysis showed that among 11 biologics, the most effective biologics were risankizumab, followed by bimekizumab, brodalumab, guselkumab, and ixekizumab, and followed by secukinumab, adalimumab, ustekinumab, and etanercept was the last. ConclusionCurrent evidence shows that risankizumab is likely to be the best option for long-term treatment of moderate-to-severe plaque psoriasis. Due to the limited quality and quantity of the included studies, more high-quality studies are needed to verify the above conclusion.
Objective To assess efficacy of a mouthwash containing 0.1% cetylpiridinium on gingivitis and plaque and its safety. Methods Multi-center randomized double-blind trial with positive control and split-mouth comparison was designed. Scaling on teeth of left side were conducted at do then on those of right side at D8. The cases rinsed five times a day in same way with assigned agents. Efficacy was measured using before-after differences of clinical and microbial variables. Re-examinations were scheduled at D4 and D8. Brushing was refrained between D0 and D4, resumed between D4 and D8. Results There were 144 patients with gingivitis included, 4 lost follow up. Data of 69 cases in test group and 71 in control group could be analyzed. Baseline data analysis showed that distributions of sex, age and values of clinical and microbial variables in both groups were well comparable. At D4 plaque accumulations of the scaled side in both groups were in same level, and Gingival index (GI), sulcus bleeding index (SBI) and VAS for halitosis were significantly reduced. At D8 the measurements of plaque index (PI), GI, SBI and VAS of halitosis decreased significantly more than those of D4. More than half of the suspected pathogenic strains were eliminated and log value of its CFU/ml decreased significantly but at same level in both groups. The balance of intra-oral bacterial flora was not disturbed. Seventeen cases in test group (24.6%) had minor and transient adverse reactions related to the mouthwash. Antimicrobial tests in vitro confirmed that the test agent could kill or inhibit growth of the pathogenic bacteria involving with oropharyngeal infection, gingivitis, periodontal diseases and caries. Conclusion The mouthwash containing cetylpiridinium could inhibit plaque, reduce severity of gingivitis and halitosis, with acceptable minor adverse reactions, similar to those of the marketed cetylpiridinum solution.
Atherosclerosis is a complex and multi-factorial pathophysiological process. Researches over the past decades have shown that the development of atherosclerotic vulnerable plaque is closely related to its components, morphology, and stress status. Biomechanical models have been developed by combining with medical imaging, biological experiments, and mechanical analysis, to study and analyze the biomechanical factors related to plaque vulnerability. Numerical simulation could quantify the dynamic changes of the microenvironment within the plaque, providing a method to represent the distribution of cellular and acellular components within the plaque microenvironment and to explore the interaction of lipid deposition, inflammation, angiogenesis, and other processes. Studying the pathological mechanism of plaque development would improve our understanding of cardiovascular disease and assist non-invasive inspection and early diagnosis of vulnerable plaques. The biomechanical models and numerical methods may serve as a theoretical support for designing and optimizing treatment strategies for vulnerable atherosclerosis.
ObjectiveTo study the correlation between neck artery vascular sclerosis and homocysteine levels in hypertensive patients. MethodsA total of 2 132 patients with hypertension participated in the program of "Stroke screening and prevention in Dongying city" were included from Sep. 2012 to Jan. 2013. Questionnaire, physical examination, biochemical blood tests and carotid artery ultrasound were conducted in all included patients. According to the level of homocysteine (Hcy), patients were divided into three groups:716 patients with Hcy level less than 12.3 mm/L were in Group 1, 703 patients with Hcy level 12.3 to 16.5 mm/L were in Group 2, and 713 patients with Hcy level more than 16.5 mm/L were in Group 3. The influence of Hcy levels on carotid atherosclerosis was analyzed. Results① The prevalence rate for carotid plaques in Groups 1, 2, and 3 were 50.28%, 60.03% and 65.36%, respectively. The prevalence rate for carotid plaques in Group 2 was higher than that in Group 1 with a statistical difference (OR=1.485, 95% CI 1.203 to 1.833, P=0.000). The prevalence rate in Group 3 was also higher than that in Group 1 with a statistical difference (OR=1.866, 95% CI 1.508 to 2.308, P=0.000). ② The prevalence rate for carotid plaques was 62.24% in the rural population, and 52.39% in the urban population. The difference between urban and rural populations was statistically significant (OR=1.500, 95% CI 1.259 to 1.788, P=0.000). ③ Using the presence of carotid plaques as a dependent variable and Hcy level as a covariant, logistic regression analysis found that the plaque formation in Group 2 was 1.491 times than in Group 1 and the plaque formation in Group 3 was 1.752 times than in Group 1. After adjusting the risk factors (gender, age, BMI, TG, TC, LDL-C, HDL-C and blood sugar level), the results showed that the plaque formation in Group 2 was 1.388 times than in Group 1, and the plaque formation in Group 3 was 1.452 times than in Group 1. ConclusionThere is a correlation between the increased incidence of carotid plaque and homocysteine levels in patients with hypertension. The incidence of carotid plaque in the rural population with hypertension is higher than that in the urban population. In the population with hypertension, high homocysteine level is an independent risk factor for the formation of carotid plaques.
Optical coherence tomography (OCT) has become a key technique in the diagnosis of coronary artery stenosis, which can identify plaques and vulnerable plaques in the image. Therefore, this technique is of great significance for the diagnosis of coronary heart disease. However, there is still a lack of automatic, multi-region, high-precision segmentation algorithms for coronary OCT images in the current research field. Therefore, this paper proposes a multi-zone, fully automated segmentation algorithm for coronary OCT images based on neutrosophic theory, which achieves high-precision segmentation of fibrous plaques and lipid regions. In this paper, the method of transforming OCT images into T in the area of neutrosophics is redefined based on the membership function, and the segmentation accuracy of fiber plaques is improved. For the segmentation of lipid regions, the algorithm adds homomorphic filter enhancement images, and uses OCT to transform OCT images into I in the field of neutrosophics, and further uses morphological methods to achieve high-precision segmentation. In this paper, 40 OCT images from 9 patients with typical plaques were analyzed and compared with the results of manual segmentation by doctors. Experiments show that the proposed algorithm avoids the over-segmentation and under-segmentation problems of the traditional neutrosophic theory method, and accurately segment the patch area. Therefore, the work of this paper can effectively improve the accuracy of segmentation of plaque for doctors, and assist clinicians in the diagnosis and treatment of coronary heart disease.
Intravascular ultrasound (IVUS) is widely used in coronary artery examination. Ultrasonic elastography combined with IVUS is very conspicuous in identifying plaque component and in detecting plaque vulnerability degree. In this study, a simulation model of the blood vessel based on finite element analysis (FEA) was established. The vessel walls generally have radial changes caused by different intravascular pressure. The signals at lower pressures were used as the pre-deformation data and the signals at higher pressure were used as the post-deformation data. Displacement distribution was constructed using the time-domain cross-correlation method, and then strain images. By comparison of elastograms under different pressures, we obtained the optimal pressure step. Furthermore, on the basis of the obtained optimize pressure step, the simulation results showed that this method could effectively distinguish characteristics between different component plaques, and could guide the later experiments and clinical applications.