China
Africa
Explore chapters and articles related to this topic
Wearable Sensors for Blood Perfusion Monitoring in Patients with Diabetes Mellitus
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Evgenii A. Zherebtsov, Elena V. Zharkikh, Yulia I. Loktionova, Angelina I. Zherebtsova, Viktor V. Sidorov, Alexander I. Krupatkin, Andrey V. Dunaev
Regulation in smooth muscle vessels is concerned with the diameter of these vessels and, as a result, with the volumetric blood flow. The contractile state of smooth muscle cells establishes the vessel diameter of a required size, which ensures active tonic tension for a long time, i.e., to maintain proper vascular tone (Table 5.2). Small arteries and arterioles play a major role in maintaining resistance to blood flow.
Properties of the Arterial Wall
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
The function of the systemic arterial system is to deliver blood at high pressure and in a continuous stream to peripheral vascular beds. From a simplistic perspective, it can be separated into three anatomical regions to serve the left ventricle as a pulsatile pump and the tissues that need a supply of blood. Each region has a distinct and separate function: (1) The large arteries, especially the elastic arteries (aorta, brachiocephalic, carotid, etc.), serve predominately as a cushioning reservoir, or “Windkessel,” that stores blood during systole and expels it to the tissue during diastole. (2) The long muscular arteries act predominately as conduits, distributing blood to the extremities; these arteries also actively modify wave propagation by changing smooth muscle tone and diameter with little change in mean arterial blood pressure. (3) The arterioles, by changing their caliber, alter peripheral resistance and therefore aid in the maintenance of mean arterial blood pressure, as well as the delivery of a steady or continuous flow of blood to the organs and tissues according to their need. Major changes in the central elastic arteries occur over long periods of time, while acute alterations in wall properties (e.g. with rise or fall in dis-tending pressure) are passive (Nichols and Edwards, 2001; Giannattasio and Mancia, 2002). Changes in the muscular arteries and arterioles most often occur acutely, and alterations in wall properties are active (Boutouyrie et al., 2000; Nichols and Edwards, 2001; Safar et al., 2003).
Arteropathies, Microcirculation and Vasculitis
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
Arteriosclerosis affects both arteries and arterioles. There is gradual replacement of vascular smooth muscle cells by collagen (Fig. 11.1) and deposition of plasma proteins in the smooth muscle to produce hyaline change. This process is accelerated by age, hypertension and diabetes mellitus. Arteriosclerosis lowers the compliance of the arterial tree, and contributes to the age-related increase in systolic blood pressure. Arteriosclerosis differs from atherosclerosis in that there is no intimal lipid deposition with resultant inflammation.
Dynamic Changes in Retinal Vessel Diameters and Arteriovenous Ratio within 10 Days of Birth
Published in Current Eye Research, 2023
Previous studies in adults have shown that the retinal artery’s diameter decreases with the onset of diabetes while the retinal vein’s diameter widens.3 In addition, when systemic blood pressure continues to rise, self-regulating vessels narrow the arterioles.4 Moreover, retinal vascular morphological changes may predict age-related cognitive decline,5 and a low AVR may indicate adverse pregnancy outcomes.6 Similarly, newborns experience parturition from inside to outside in the neonatal period. Whole-body microcirculation is influenced by sudden changes in the environment, the gradual establishment of pulmonary circulation, and changes in blood oxygen content. These changes may theoretically lead to severe relaxation and contraction of the retinal blood vessels shortly after birth. With the development of fundus photography systems and semi-automatic measurement software for newborns, the diameter of the retinal vessels in newborns can also be quantitatively analyzed. Kandasamy et al. measured the retinal blood vessels of 20 full-term newborns within 7 days of birth using digital software and found that the average AVR was 0.66. However, there are no studies on early changes in the retinal vessel diameter and AVR with age in full-term newborns.
Arteriolar hyalinosis and renal outcomes in patients with immunoglobulin A nephropathy
Published in Renal Failure, 2022
Yunzhu Shen, Tangli Xiao, ZhiKai Yu, Yinghui Huang, Ting He, Haiyang Li, Jun Zhang, Jiachuan Xiong, Jinghong Zhao
Meanwhile, there are striking differences between the prognosis of the two groups, which implies that arteriolar hyalinosis is a pathological feature of poor prognosis. Furthermore, as the degree of arteriolar hyalinosis increases, the prognosis worsens. In addition, we have observed the relationship between arteriolar hyalinosis and hypertension. Wang et al. [35] analyzed that hypertensive IgAN patients with ischemic renal injury has a poorer prognosis. And this study has showed that the patients with arteriolar hyalinosis and hypertension in IgAN suffer a worse prognosis. And at the same time, hypertension seemed not to be an independent risk factor to the patients with arteriolar hyalinosis in this study, which is inconsistent with the study of Miyabe et al. [36]. The possible reasons are that pathological scoring systems for IgAN, such as Oxford classification, without considering arteriolar hyalinosis, and the MESTC primary are also included, while arteriolar hyalinosis is not included in multivariate regression analysis. Furthermore, the primary pathological manifestation of renal damage caused by the essential hypertension is arteriolar hyalinosis [37]. The possible reason for the results of our subgroup is that part of the effect of hypertension on the prognosis of IgAN works by causing hyaline changes in renal arterioles. However, it still needs further research on the internal mechanism of hypertension and arteriolar hyalinosis in IgAN.
High-Resolution Imaging of Retinal Vasculitis by Flood Illumination Adaptive Optics Ophthalmoscopy: A Follow-up Study
Published in Ocular Immunology and Inflammation, 2020
Marie-Hélène Errera, Marthe Laguarrigue, Florence Rossant, Edouard Koch, Céline Chaumette, Christine Fardeau, Mark Westcott, José-Alain Sahel, Bahram Bodaghi, Jonathan Benesty, Michel Paques
We show here that thanks to its capabilities to document at a microscopic level both the width of perivascular sheathing and the vascular narrowing, AOO brings new opportunities for the evaluation of retinal vasculitis. This may not only reveal the severity of the disease but also indicate the risk of local complications. Albeit AAO imaging is dependent on clear media, and cannot be performed in cases of media opacities such as vitritis, it offers the unique possibility to detail fine features of paravascular opacities. We demonstrated for instance that IRVAN was associated with perivenous opacities. We also observed in many cases the presence of arteriolar narrowing associated with arteritis. The contrast was highly variable between the infiltrate and the surrounding retina, which may be due to the specific nature of the infiltrate or to the background pigmentation. Infiltrates associated with blood-retinal barrier rupture were more often located along the major vessels of the temporal arcades in an area within 10° from the optic disc. We also documented here the time-course of resolution of sheathing, showing that the width of the sheathing was halved in 3 months for one patient who underwent serial AOO imaging. Recurrence was often observed in the same site as initially, suggesting that cell infiltrates do not occur randomly but that there are preferential sites. Recently, using another software, Mahendradas et al. have also shown a complete resolution of the sheathing by AO on follow-up.14