The clinical significance of the parameters of the capillary bed, heart rate variability, and computer bronchophonography in the differential diagnosis of diseases accompanied by prolonged cough in children

Differentia! diagnosis of the causes of prolonged cough is difficult because of its multifactorial nature. Diagnostics in case of a cough that persists for more than 4 weeks is based on clinical data, but sometimes it is not enough to establish a diagnosis. This issue led to the development of algorithms based on additional diagnostic criteria evaluated with modern non-invasive functional methods for diagnosing diseases accompanied by a prolonged cough in children.Aim. To determine the differential diagnostic value of the functional parameters of the capillary bed, respiratory tract, and autonomic nervous system in children with diseases accompanied by a prolonged cough (more than 4 weeks).Methods. 238 children aged from 2 to 17 years with prolonged cough were examined in inpatient or outpatient settings and divided into 4 groups: Group 1 (n = 68) - patients with acute or exacerbation of the chronic infectious upper respiratory tract diseases; Group 2 (n = 53) - patients with lower respiratory tract infection; Group 3 (n = 39) - patients with allergic rhinitis; Group 4 (n = 78) - patients with bronchial asthma. All patients underwent standard clinical examination. The diagnostic test also included functional assessment of microcirculation, autonomic nervous system, and respiratory system via computer capillaroscopy of the nail bed, evaluation of heart rate variability, and computer bronchophonography.Results. Patients with allergic diseases of the respiratory tract, especially with asthma, show a change in all parts of the capillary bed and a significant increase in the zone of perivascular edema in combination with parasympathicotonia, in contrast to children with infectious diseases of the respiratory system, who showed a change in microcirculation parameters mainly in the venous capillaries in combination with sympathicotonia. In addition, children with prolonged coughing, regardless of its origin, showed functional changes in the high-frequency acoustic parameters of the respiratory system in the form of an increase in the coefficient of the high-frequency acoustic component of breathing (ф3), which indicates bronchial hyperreactivity.Conclusion. The functional parameters of the microvasculature, autonomic nervous system, and respiratory tract can be used as additional differential diagnostic criteria and included in algorithms for diagnosing respiratory diseases of various origins in childhood, contributing to the early detection of the pathology and timely targeted therapy.

A nonlinear multi-scale model for blood circulation in a realistic vascular system

In the last decade, numerical models have become an increasingly important tool in biological and medical science. Numerical simulations contribute to a deeper understanding of physiology and are a powerful tool for better diagnostics and treatment. In this paper, a nonlinear multi-scale model framework is developed for blood flow distribution in the full vascular system of an organ. We couple a quasi one-dimensional vascular graph model to represent blood flow in larger vessels and a porous media model to describe flow in smaller vessels and capillary bed. The vascular model is based on Poiseuille’s Law, with pressure correction by elasticity and pressure drop estimation at vessels' junctions. The porous capillary bed is modelled as a two-compartment domain (artery and venous) using Darcy’s Law. The fluid exchange between the artery and venous capillary bed compartments is defined as blood perfusion. The numerical experiments show that the proposed model for blood circulation: (i) is closely dependent on the structure and parameters of both the larger vessels and of the capillary bed, and (ii) provides a realistic blood circulation in the organ. The advantage of the proposed model is that it is complex enough to reliably capture the main underlying physiological function, yet highly flexible as it offers the possibility of incorporating various local effects. Furthermore, the numerical implementation of the model is straightforward and allows for simulations on a regular desktop computer.

Virtual embolization for treatment support of intracranial AVMs using an interactive desktop and VR application

Purpose The treatment of intracranial arteriovenous malformations (AVM) is challenging due to their complex anatomy. For this vessel pathology, arteries are directly linked to veins without a capillary bed in between. For endovascular treatment, embolization is carried out, where the arteries that supply the AVM are consecutively blocked. A virtual embolization could support the medical expert in treatment planning. Method We designed and implemented an immersive VR application that allows the visualization of the simulated blood flow by displaying millions of particles. Furthermore, the user can interactively block or unblock arteries that supply the AVM and analyze the altered blood flow based on pre-computed simulations. Results In a pilot study, the application was successfully adapted to three patient-specific cases. We performed a qualitative evaluation with two experienced neuroradiologist who regularly conduct AVM embolizations. The feature of virtually blocking or unblocking feeders was rated highly beneficial, and a desire for the inclusion of quantitative information was formulated. Conclusion The presented application allows for virtual embolization and interactive blood flow visualization in an immersive virtual reality environment. It could serve as useful addition for treatment planning and education in clinical practice, supporting the understanding of AVM topology as well as understanding the influence of the AVM’s feeding arteries.

Parameters of cutaneous microvasculature in men of working age with newly diagnosed arterial hypertension

OBJECTIVE: To investigate structural and functional features of cutaneous microvasculature in men of working age with newly diagnosed arterial hypertension (AH). MATERIALS AND METHODS: The study included 161 apparently healthy men from 30 to 60 years, who underwent a comprehensive examination of cardiovascular system “from the heart to the capillaries”. Control group (CG) included 60 normotensive men. AH group included 101 men with elevated BP. RESULTS: There is no rarefaction of the capillary bed and latent fluid retention in the interstitial space in the skin in men with AH. No data were obtained for increased endothelial, neurogenic and myogenic tone of resistive cutaneous precapillary arterioles in AH group, but a decrease in the perfusion efficiency of the endothelial and myogenic mechanisms of tissue perfusion modulation was noted. CONCLUSION: Obtained results allow making the assumption that metabolic disorders at the level of capillaries that are of a systemic nature prevail in men with the onset of AH.

The Ageing Brain: Investigating the Role of Age in Changes to the Human Cerebral Microvasculature With an in silico Model

Ageing causes extensive structural changes to the human cerebral microvasculature, which have a significant effect on capillary bed perfusion and oxygen transport. Current models of brain capillary networks in the literature focus on healthy adult brains and do not capture the effects of ageing, which is critical when studying neurodegenerative diseases. This study builds upon a statistically accurate model of the human cerebral microvasculature based on ex-vivo morphological data. This model is adapted for “healthy” ageing using in-vivo measurements from mice at three distinct age groups—young, middle-aged, and old. From this new model, blood and molecular exchange parameters are calculated such as permeability and surface-area-to-volume ratio, and compared across the three age groups. The ability to alter the model vessel-by-vessel is used to create a continuous gradient of ageing. It was found that surface-area-to-volume ratio reduced in old age by 6% and permeability by 24% from middle-age to old age, and variability within the networks also increased with age. The ageing gradient indicated a threshold in the ageing process around 75 years old, after which small changes have an amplified effect on blood flow properties. This gradient enables comparison of studies measuring cerebral properties at discrete points in time. The response of middle aged and old aged capillary beds to micro-emboli showed a lower robustness of the old age capillary bed to vessel occlusion. As the brain ages, there is thus increased vulnerability of the microvasculature—with a “tipping point” beyond which further remodeling of the microvasculature has exaggerated effects on the brain. When developing in-silico models of the brain, age is a very important consideration to accurately assess risk factors for cognitive decline and isolate early biomarkers of microvascular health.

RARE CASE OF CEREBRAL ARTERIOVENOUS MALFORMATION PRESENTING AS PARASTHESIA OF ALL FOUR LIMBS

Brain arteriovenous malformations (AVM) are abnormal vascular connection between arteries (pial vessels) and veins via a nidus of vessels through which shunting of blood occurs in the absence of true capillary bed. When intracranial AVMs are encountered at cross-sectional imaging, other diagnoses like malignant dural arteriovenous stulas, and moyamoya disease must also be considered. Secondary effects such as gliosis, neurologic decits, venous congestion, hydrocephalus should be included in the radiology report. Imaging ndings inuence the clinical management by neurosurgeons.

Uterine artery embolization for uterine arterio-venous malformation

Uterine arteriovenous malformations (AVM) as a cause of abnormal uterine bleeding are listed under “not otherwise classified” in Palm-Coein classification, is an abnormal communication between an artery and vein without an intervening capillary bed resulting in increased pressure and high velocity in the venous system. We report the case of heavy menstrual bleeding in a thirty-five-year-old primiparous lady for five years with fourteen weeks sized uterus and six gm hemoglobin. Ultrasound revealed an enlarged uterus with tubular spaces and color doppler showed tubular anechoic structures, both within the myometrium, with low resistance and high-velocity pattern suggestive of uterine arteriovenous malformations. Because of nonresponse to medical management, uterine artery embolization was carried out following which she had significant reduction in menstrual bleeding emphasizing it as a differential diagnosis in all cases presenting with heavy menses. Uterine artery embolization appears to be an effective modality of treatment especially in women whose wish to preserve fertility.

Imaging the construction of capillary networks in the neonatal mouse brain

Capillary networks are essential for distribution of blood flow through the brain, and numerous other homeostatic functions, including neurovascular signal conduction and blood–brain barrier integrity. Accordingly, the impairment of capillary architecture and function lies at the root of many brain diseases. Visualizing how brain capillary networks develop in vivo can reveal innate programs for cerebrovascular growth and repair. Here, we use longitudinal two-photon imaging through noninvasive thinned skull windows to study a burst of angiogenic activity during cerebrovascular development in mouse neonates. We find that angiogenesis leading to the formation of capillary networks originated exclusively from cortical ascending venules. Two angiogenic sprouting activities were observed: 1) early, long-range sprouts that directly connected venules to upstream arteriolar input, establishing the backbone of the capillary bed, and 2) short-range sprouts that contributed to expansion of anastomotic connectivity within the capillary bed. All nascent sprouts were prefabricated with an intact endothelial lumen and pericyte coverage, ensuring their immediate perfusion and stability upon connection to their target vessels. The bulk of this capillary expansion spanned only 2 to 3 d and contributed to an increase of blood flow during a critical period in cortical development.

Retina Metabolism and Metabolism in the Pigmented Epithelium: A Busy Intersection

The outer retina is nourished from the choroid, a capillary bed just inside the sclera. O2, glucose, and other nutrients diffuse out of the choroid and then filter through a monolayer of retinal pigment epithelium (RPE) cells to fuel the retina. Recent studies of energy metabolism have revealed striking differences between retinas and RPE cells in the ways that they extract energy from fuels. The purpose of this review is to suggest and evaluate the hypothesis that the retina and RPE have complementary metabolic roles that make them depend on each other for survival and for their abilities to perform essential and specialized functions. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.