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Venous Return and Vascular Function
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
There is a limited amount of smooth muscle in the walls of venules and veins. This smooth muscle is innervated by sympathetic nerves. The way in which veins are distended by blood inside the veins depends on the pressure of blood inside them and this depends on venomotor tone which is modulated by sympathetic nerve activity. When smooth muscles in the walls of the veins and venules are stimulated, the compliance curve is displaced to the right and blood is ‘squeezed’ out of the venous system towards the heart.
Ischemia-Reperfusion: A Model of Acute Intestinal Inflammation
Published in William J. Snape, Stephen M. Collins, Effects of Immune Cells and Inflammation on Smooth Muscle and Enteric Nerves, 2020
Barbara J. Zimmerman, Paul Kubes, D. Neil Granger
The contention that oxy-radicals and neutrophils are involved in ischemia-reperfusion is further supported by work using intravital microscopy as a method of neutrophil detection. In this experimental model the mesentery is draped over an optically clear viewing pedestal to allow for transillumination of the mesentery. The mesenteric microcirculation is then observed through an intravital video microscope and a video camera mounted on the microscope projects the image onto a black and white monitor where it is recorded for play-back analysis (final magnification 1400X). Single unbranched venules (diameter=25–35 μm) are selected for observation. The diameters are measured using a video image-shearing monitor.
Unexplained Fever Associated With Hypersensitivity and Auto-Immune Diseases
Published in Benedict Isaac, Serge Kernbaum, Michael Burke, Unexplained Fever, 2019
It is a vasculitis affecting predominantly small venules and it is easy to diagnose. We will not describe its painful and highly colored lesions occurring usually over the shins, with fever, malaise, and arthralgias.
Subclinical Retinal Capillary Abnormalities in Juvenile Systemic Lupus Erythematosus without Ocular Involvement
Published in Ocular Immunology and Inflammation, 2023
Büşra Yılmaz Tuğan, Hafize Emine Sönmez, Nurşen Yüksel, Levent Karabaş
According to studies on diabetic retinopathy, retinal vein occlusion, sickle cell retinopathy, and Behçet disease without eye involvement, capillaries in DCP are more susceptible to ischemia than in SCP.21,22 This could be attributed to the fact that the capillary structure of SCP and DCP differs, with the SCP containing transverse capillaries that merge arterioles and venules and DCP containing capillaries that are arranged radially and converging in a center (epicenter), forming polygonal-shaped units. These units empty into the superficial venules that are connected to superficial veins.23 Furthermore, DCP has a complex vascular structure that meets the high metabolic needs of the highly differentiated photoreceptors, is distant from the arterioles, and is more susceptible to being affected when blood flow is compromised as it drains into the superficial venules.24 Although SCP parameters were lower in the JSLE group compared to HCs, this difference did not reach statistical significance. All VD parameters in DCP were observed to significantly decreased in JSLE patients. Consistent with all these findings in the literature, we suggested that retinal vascular involvement in JSLE patients starts from DCP and DCP is more predominantly affected by inflammatory damage in the vessel wall because of its organization and role in meeting metabolic demand. Recent literature demonstrated that DCP nonperfusion has a significant influence on photoreceptor integrity, therefore future research studying decreased VD in the DCP could be informative.25
Role of the Cadaver Lab in Lymphatic Microsurgery Education: Validation of a New Training Model
Published in Journal of Investigative Surgery, 2022
Lucian P. Jiga, Corrado C. Campisi, Zaher Jandali, Melissa Ryan, Michele Maruccia, Luigino Santecchia, Mario Cherubino, Janniko Georgiadis
Extremity lymphedema causes significant morbidity in terms of physical limitations and infection risk [1, 2]. The development of microsurgical techniques (lymphaticovenous anastomosis - LVA) to restore lymph flow by bypassing obstructed lymphatic pathways into subdermal venules have offered a functional repair for the disease with consistent clinical outcomes reported world-wide [3–5]. More recently, vascularized lymph node transfers (VLNT), vascularized lymphatic vessels transfers (VLVT) or VLNT combined with simultaneous LVA have emerged as novel microsurgical approaches for lymphatic reconstruction [6, 7]. Although the selection criteria of LVA versus VLNT in the treatment of extremity lymphedema remains a highly debated subject, these techniques yielded promising results in terms of pain and swelling alleviation in uni- or bilateral extremity lymphedema across several centers [8, 9].
Selexipag for the treatment of pulmonary arterial hypertension
Published in Expert Review of Respiratory Medicine, 2021
Léon Genecand, Julie Wacker, Maurice Beghetti, Frédéric Lador
PAH can be further stratified according to the part of the vasculature mainly damaged: 1) PAH when the arteries (medium and small) are involved and 2) pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) when the venules, respectively, the capillaries, are damaged. While PVOD and PCH were formerly in a subgroup of PAH (group 1ʹ), the proceedings of the 6th World symposium on PH suggested to unify these entities in a group 1.6 called PAH with overt features of venous/capillaries (PVOD/PCH) involvement [2]. This decision was based on the growing acknowledgment that overlaps between arteries, capillaries, and venules involvements are important. PAH, PCH, and PVOD are then a spectrum of diseases rather than strictly different entities. However, differentiation between PAH with or without overt features of PVOD/PCH is mandatory because the therapeutic approach significantly differs. In fact, no randomized controlled trial (RCT) included patients with PCH/PVOD features. When PCH/PVOD is suspected, classical vasodilator therapies should be used under close supervision in an expert center due to the risk of pulmonary edema [1,3]. Early transplantation listing is a priority for these patients with a poor prognosis. PVOD/PCH is suspected based on CT findings (septal lines, mediastinal lymph node enlargement, and centrilobular ground glass opacities), low DLCO, poor response to PAH therapy, specific genetic background, and eventually occult alveolar hemorrhage when bronchoalveolar lavage is performed [2].