Vessels Of Different Caliber Research Articles

Effect of Electromagnetic Wi-Fi Radiation On The Development Of Chicken Embryo

Abstract Significant technological progress in the field of wireless devices that were primarily intended for military purposes, has resulted in their common manipulation by the general population. Wi-Fi, mobile phones, and other modern devices offer many advantages to their users. On the other hand, their excessive usage creates an environmental burden, also known as electrosmog. The objective of our current study was the observation of the Wi-Fi radiation effect on the histo-logical structure of the organs in the 9-day-old chicken embryo. On day 9 of incubation, the embryological material was routinely processed for preparation of hematoxylin-eosin, picrosirius red and periodic acid Schiff stained histological sections. Radiation with a frequency of 2.4 GHz and average power density of 300 µW.m−2 applied during the entire development up to the 9th embryonic day did not fundamentally affect general organogenesis. However, in the parenchyma of organs such as the liver, spleen, lungs, kidneys, and gonads, as well as in the developing mesenchyme, obvious vascular congestion of the blood vessels of different caliber was observed. Also, an increase in collagen and glycosaminoglycans production in the cartilaginous matrix and perichondrium of the future bone skeleton as well as developing connective tissue was noted. Although these morphological changes were just subtle, they point to the Wi-Fi radiation’s ability to influence the histogenesis of the individual.

МОРФОГЕНЕЗ ЯИЧНИКОВ ЦЫПЛЯТ-БРОЙЛЕРОВ ПРИ ИСПОЛЬЗОВАНИИ КОРМОВОЙ ДОБАВКИ «ЯНТАРНЫЙ ХОЛОДОК»

The aim of research is to study the development of structural and functional features of the reproductive system of broiler chickens using the feed additive Yantarnyj holodok. Research was conducted on broiler chickens of the Ross-308 cross under experimental conditions, while for the experiment, control and experimental groups of 30 heads each were created, starting from the day-old age, broiler chickens of the control group received tap water from vacuum drinkers without adding a feed additive, and chickens of the experimental group were given the feed additive Yantarnyj holodok daily in a dose of 1.5 l / t with drin¬king water until the end of growing. As a main diet, broiler chickens of both groups received compound feed of Ptitsefabrika Artemovskaya LLC. The use of the feed additive Yantarnyj holodok had a positive effect on the live weight gain, which by the end of the experiment was 2,938.10 ± 405.34 g, which was 1.9 % higher than the average value in the control group. 100 % survival of broiler chickens in the experimental group was established. Histological studies revealed the process of gradual improvement of the ovary structure, the formation of its cortical and cerebral zones. At the age of 10 days, the histological structure of the ovary was not formed and represented only the protein coat, and the internal part was represented by chaotically scattered follicles, among which follicles in the pertification state were found. By the 20th day, the cortical and medullar zones of the ovary could be seen. By the 35th day, the formation of egg-bearing mounds with a zone of formed follicles of varying degrees of maturity is observed, but complete maturation of follicles with a formed egg cell was not detected in the studied individuals. The medullar zone of the ovary is rich in blood vessels of different calibers, that is, the vascularization of the ovary of chickens of this age is significantly developed.

Systemic vasculitis: a modern view on the problem

The aim of the study was to summarize the literature data on various types of systemic vasculitis, their mechanisms of development, diagnostic possibilities, and to describe a clinical case. Systemic vasculitis is a group of diseases with heterogeneous etiology, which involve vessels of different calibers, predominantly small and/or medium, manifesting as multi-organ dysfunction, difficult to treat, and with a poor prognosis. Currently, the following types are distinguished: large vessel vasculitis; medium vessel vasculitis; small vessel vasculitis; variable vessel vasculitis; single-organ vasculitis; vasculitis associated with systemic diseases; vasculitis associated with specific etiology. In the clinic of internal medicine, kidney involvement (glomeruloand tubulopathies, renal insufficiency), skin (ulcerative-necrotic and trophic changes), lungs (interstitial involvement, respiratory insufficiency, recurrent pneumonias), and central nervous system (acute ischemic events, thromboses, polyneuropathies, cognitive disorders, gait disturbances), heart (myocarditis with heart failure) are most commonly encountered. Systemic vasculitis most often manifests in winter and spring periods. Hemorrhagic vasculitis and Kawasaki disease are most commonly seen among children and young adults. In the post-COVID era, systemic vasculitis has been detected more frequently. The study presents the results of personal observation of a patient suffering from infectious-toxic systemic vasculitis.

Morphological Evaluation and Immunohistochemical Analysis of the Reparative Potential of the Buccal Fat Pad.

Background and Objectives: There are many surgical techniques for oroantral communication treatment, one of which is the buccal fat pad. Of particular interest is the high reparative potential of the buccal fat pad, which may be contributed to by the presence of mesenchymal stem cells. The purpose of this work is to evaluate the reparative potential of BFP cells using morphological and immunohistochemical examination. Materials and Methods: 30 BFP samples were provided by the Clinic of Maxillofacial and Plastic Surgery of the Russian University of Medicine (Moscow, Russia) from 28 patients. Morphological examination of 30 BFP samples was performed at the Institute of Clinical Morphology and Digital Pathology of Sechenov University. Hematoxylin-eosin, Masson trichrome staining and immunohistochemical examination were performed to detect MSCs using primary antibodies CD133, CD44 and CD10. Results: During staining with hematoxylin-eosin and Masson's trichrome, we detected adipocytes of white adipose tissue united into lobules separated by connective tissue layers, a large number of vessels of different calibers, as well as the general capsule of BFP. The thin connective tissue layers contained neurovascular bundles. Statistical processing of the results of the IHC examination of the samples using the Mann-Whitney criterion revealed that the total number of samples in which the expression of CD44, CD10 and CD133 antigens was confirmed was statistically significantly higher than the number of samples where the expression was not detected (p < 0.05). Conclusions: During the morphological study of the BFP samples, we revealed statistically significant signs of MSCs presence (p < 0.05), including in the brown fat tissue, which proves the high reparative potential of this type of tissue and can make the BFP a choice option among other autogenous donor materials when eliminating OAC and other surgical interventions in the maxillofacial region.

PATHOGENETIC FEATURES OF ADENOMYOSIS DEVELOPMENT IN WOMEN OF REPRODUCTIVE AGE IN THE POST-COVID PERIOD

Purpose. To study the prevalence and forms of adenomyosis for women of reproductive age after COVID-19, to study pathomorphological changes in the uterine tissues of women of reproductive age with adenomyosis after COVID-19.&#x0D; Materials and methods. We examined 114 patients of reproductive age who underwent hysterectomy for various pathologies. Of these, 40 patients (35%) in 2019 before the COVID-19 pandemic, and during the pandemic in 2021 - 36 patients (31.6%), in 2022 - 38 (33.4%) patients.&#x0D; Results. The study found that the total number of histologically confirmed adenomyosis in patients of reproductive age increased from 55% in 2019 (before the COVID-19 pandemic) to 66.6% and 71% in 2021 and 2022, respectively; the number of diffuse adenomyosis increased significantly from 12.5% in 2019 (before the COVID-19 pandemic) to 41.6% and 47.4% in 2021 and 2022, respectively; the percentage of diffuse adenomyosis in relation to other forms of adenomyosis increased from 22.7% in 2019 (before the COVID-19 pandemic) to 62.5% and 66.6% in 2021 and 2022, respectively. Given the increase in the prevalence of adenomyosis in the post-COVID period compared to the period before the COVID-19 pandemic, we studied pathomorphological changes in the basal layer of the endometrium and the inner layer of the myometrium that correlated with the clinical features of the disease in the patients who participated in the study. The study included cases with histologically confirmed adenomyosis Pathologically detected changes in the endometrium and inner layer of the myometrium in adenomyosis after COVID-19, namely the line of separation between the endometrium and myometrium is unclear, vessels in the form of clusters, thickwalled, narrowed lumen, edema between fibers, edema between fibers and around vessels, thickening of the vessel wall and narrowing of the lumen, pronounced revascularization, the presence of myxomatous edema, foci of hemosiderosis in the interstitial tissue, thrombosis of vessels of different caliber with hemorrhages, and microcirculatory disorders.&#x0D; Conclusion. The results obtained indicate that after COVID-19 disease, the total number of histologically detected adenomyosis in women of reproductive age increased, and the number of diffuse adenomyosis increased. Characteristic changes occurred in the uterine tissue at the border of the endometrium and myometrium, which are morphologically confirmed.

Leukocytoclastic vasculitis due to reactivation of virus varicella zoster. Case report

Vasculitis is an inflammatory process of blood vessels, which can affect vessels of different calibers causing necrosis of tissues and organs. The type of vasculitis with the highest incidence is the cutaneous one called leukocytoclastic vasculitis (LCV) through mainly by a hypersensitivity process or formation of immune complexes to different known and unknown factors. The diagnosis of LCV includes a large number of laboratory and imaging parameters aimed at ruling out systemic disease, which causes delay in starting treatment, prolongation of ischemia and increased tissue damage. The fundamental contribution of the present report case is to show the importance of timely diagnosis of skin limited small vessel LCV to apply an early therapeutic scheme that produces the least possible damage to the affected tissue. A case of a 54-year-old female patient is presented with mucosal and cutaneous manifestations of reactivation of the varicella-zoster virus as a triggering factor for LCV. An adequate protocol was proposed to diagnose through anamnesis and exhaustive physical examination that would allow guiding the paraclinical evaluation to rule out a systemic disease and to obtain a comprehensive and timely therapeutic approach with short-term resolution of the pathology.

Various techniques for anastomosis of pulmonary arteries with size mismatch during lung transplantation.

Various techniques for anastomosis of pulmonary arteries with size mismatch during lung transplantation.

Макроскопічні зміни в серці та кровоносних судинах свійських і декоративних птахів за туберкульозу

The results of the study of macroscopical changes in the structural components of the heart and the walls of vessels of different caliber in domestic and ornamental birds that died from tuberculosis are presented. The object of the study was the forms of cardiovascular pathologies in generalized poultry tuberculosis. The aim of the study is to identify and classify macroscopical changes in the heart and wall of bloods vessels in generalized poultry tuberculosis. Materials and research methods. The work was done at the Department of Normal and Pathological Morphology of KhSZA. The following methods were used: pathological autopsy, its analysis, macro-microscopic examination of the heart and wall of bloods vessels&nbsp; using weak-optical lenses, thanatogenetic analysis. 18 adult birds of different species with a comprehensively established diagnosis of "Tuberculosis avium" were studied: pheasants (n = 5), peacocks (n = 3), quail (n = 7), chickens (n = 3). Result of the research. The following cardiac pathologies were diagnosed: cardiac tamponade, pericarditis (constrictive and exudative-constrictive with obliteration of the pericardial cavity); myocarditis; areas of ischemia with an area of damage from 10 % to 50 % or more. Using weak-fold optical lenses in the myocardium of individual birds, miniature scars were detected, located partially perivascular (diagnosed with cardiosclerosis, fibrosis with a diffuse structure, focal hypertrophy of preserved areas of the myocardium). Vascular pathologies differed in complexity and intensity. Ornamental birds were diagnosed with aortic sclerosis, a complication of atherosclerosis (thrombosis, hemorrhage into a disintegrated atheroma), rupture of the aorta and other vessels, hemorrhages, hematomas, anemia, ischemia, thrombosis of mesenteric vessels, thrombophlebitis.

Issues of pathology of a new coronavirus infection CoVID-19

Relevance of the problem of a new COVID-19 coronavirus infection is obvious. Among its most important aspects that require special study, are pathogenesis and morphological changes in severe forms of the disease. Material and methods. The analysis of 18 autopsy observations was carried out. Along with routine assessment of macro – and microscopic changes, immunohistochemical studies of lungs and other organs were performed using sera against antigens CD2,3,4,5,7, 20,31,34, 56,57,69; the presence of Fe 2+ and Fe 3+ was detected in the lungs and liver. Results. Structural changes in the lungs may be associated with cytopathic and cytoproliferative effects of the virus with damage to both the ciliary and alveolar epithelium, as well as the formation of hyaline membranes. Cellular infiltration is mainly represented by suppressor populations of T-lymphocytes and macrophages. Endothelial damage, vascular thrombosis of vessels of different calibers, and hemorrhages were detected. Many organs (lymph nodes, spleen, intestines, brain, adrenal glands) show changes that may indicate generalization of viral infection, and infiltration of CD8+ lymphocytes in the kidneys, liver, adrenal glands, pericardium,and intestines indicates a probable autoimmune component of pathogenesis. In the liver and lungs deceased from COVID-19 only small clusters of Fe 3+ and Fe 2+ granules were detected, which can be associated (including in our control observation) with liver damage in malaria.

Development of an app for fluid dynamics simulations in small and large vessels

The rheological properties of the blood depend on numerous factors among which the geometry and the size of the conduit in which the blood circulates. The human body is made up by vessels having a different structure and characteristics, which depend on the function they perform, above all on the pressure they have to bear generated at the cardiac level. So, a great criticality when approaching a study on blood flow behavior in the circulatory system is to use an appropriate mathematical model for the circulating fluid. Though the CFD analysis (computational fluid dynamics), going to investigate what are the differences produced by the use of models in the study of vessels of different caliber can be a valid support in the study of vessel fluid dynamics, in particular if they are affected by pathologies. In this regard, the aim of this work, is through the implementation of an application, to carry out a statistical analysis of the effects of different blood flow models in arteries to identifying a prediction about the percentage variation of the shear stress indices involved in the impact of atherosclerotic plaque.

Embolización venosa transcateter de várices gástricas con coils

Los espirales de embolización (coils o microcoils) son los agentes más comúnmente usados, con un éxito técnico reportado en aproximadamente el 81-100 % de los casos. Los espirales o coils se encuentran disponibles en una amplia variedad de configuraciones y tamaños, lo que permite acomodarse a vasos de distintos calibres; además, por su buena radiopacidad, tienen la ventaja de ser liberados con precisión. Los espirales o coils son el análogo de una ligadura arterial quirúrgica, debido a que producen una oclusión mecánica por su posicionamiento en el lumen vascular, lo que disminuye el flujo sanguíneo, y sus fibras sintéticas tienen un efecto trombogénico adicional.&#x0D; Caso: presentamos cuatro casos del Hospital Universitario Fundación Santa Fe de pacientes con várices gástricas tratadas satisfactoriamente con embolización transcatéter con coils, los cuales tuvieron un buen resultado técnico; además presentamos una revisión de la literatura.

ОПТИКО-ЕЛЕКТРОННІ ТЕХНОЛОГІЇ ОЦІНЮВАННЯ ЗМІНИ ПЕРИФЕРІЙНОГО КРОВООБІГУ ПРИ ФОТОННОМУ ВПЛИВІ ДЛЯ КОМПЛЕКСНОГО ЛІКУВАННЯ ХРОНІЧНИХ УСКЛАДНЕНЬ ЦУКРОВОГО ДІАБЕТУ

The paper deals with the prospect of using the photoplethysmographic method for the evaluation of microcirculatory changes in peripheral circulation to study the processes that occur during photonic physiotherapy exposure for the complex treatment of chronic complications of diabetes. It is shown that photonic radiation helps to increase the elasticity of the walls of blood vessels, the elasticity of erythrocytes, oxygen transport function of the blood, the activity of cell membranes, the acceleration of processes of tissue regeneration, the reduction of lipid oxidation, the normalization of rheologic indices. After procedures of phototherapy in patients, the syndrome of thermoamputation disappeared, swelling of the legs decreased, as well as significantly decreased pain in the legs, numbness took place, leg cramps stopped. It is shown that photonic radiation of the Barva apparatus leads to anti-inflammatory, desensitizing, analgesic, antispasmodic, and anti-edema actions, which was confirmed in this study in the treatment of patients with complications of diabetes. To control the level of peripheral circulation, a photoplethysmographic method was used, which, compared to other known methods of blood circulation research, has certain advantages, because it allows to conduct studies in both transient and reflected light. It allows to obtain useful information about vascular activity, vascular response to specific substances, as well as to study blood circulation in isolated vessels of different caliber (veins, arteries, etc.). In addition, the photosensor does not cause compression of vessels of biological tissue, that is, does not cause impaired blood circulation. Thus, it is obvious that the most promising direction of registration of physiological parameters is the use of non-invasive methods of diagnosis, among which the wide development has received optical methods of registration and transformation of biomedical information and allows to study microcirculation in human tissues without impaired circulation in the study area, which is essential for medical practice.

In vivo characterization of abnormalities in small-bowel diseases using probe-based confocal laser endomicroscopy.

Background and study aims Probe-based confocal laser endomicroscopy (pCLE) enables real-time optical biopsy. Little is known about pCLE imaging deep inside the small bowel, therefore the aim of this study was to determine its usefulness. Patients and methods Between April 2014 and January 2016, we performed 38 pCLE examinations during double-balloon enteroscopy with intravenous fluorescein in 37 patients with: tumors (n = 10), vascular disorders (n = 6), inflammatory diseases and drug injuries (n = 13), other disorders (n = 4), and normal findings (n = 4). We measured the calibers of capillary and lymphatic vessels at 15 different sites and compared the calibers between pCLE images and histopathology. We also compared pCLE findings with pathologic diagnosis. Results The inner diameters of capillary vessels beneath the epithelium and in the middle of villi were 16.2 ± 3.0 µm and 14.5 ± 3.1 µm, respectively, in the pCLE images, but these were not consistent with formalin-fixed paraffin-embedded histology. In tumors, larger capillary vessels were observed in aggressive malignant lymphoma and metastasis, and a “soccer ball-like pattern” constituting homogenous dark cells packed with polygonal, narrower capillary vessels was characteristic in pCLE images of a malignant lymphoma follicle. Hereditary hemorrhagic telangiectasia and angiodysplasia contained anastomosis of capillary vessels of different calibers. In IgA vasculitis, segmental capillary strictures were observed. Intestinal lymphangiectasia with protein-losing enteropathy contained a reticular network of lymphatic vessels and dilated lymphatic ducts accompanied by numerous cell gaps. pCLE findings corresponded to pathologic diagnosis in 32 examinations (91 %). Conclusions pCLE is useful for in vivo analysis of abnormalities of the capillary and lymphatic vessels and epithelium, and for diagnosis in various small-bowel diseases.

Loss of endothelial barrier integrity in mice with conditional ablation of podocalyxin (Podxl) in endothelial cells

Podocalyxin (Podxl) has an essential role in the development and function of the kidney glomerular filtration barrier. It is also expressed by vascular endothelia but perinatal lethality of podxl−/− mice has precluded understanding of its function in adult vascular endothelial cells (ECs). In this work, we show that conditional knockout mice with deletion of Podxl restricted to the vascular endothelium grow normally but most die spontaneously around three months of age. Histological analysis showed a nonspecific inflammatory infiltrate within the vessel wall frequently associated with degenerative changes, and involving vessels of different caliber in one or more organs. Podxl-deficient lung EC cultures exhibit increased permeability to dextran and macrophage transmigration. After thrombin stimulation, ECs lacking Podxl showed delayed recovery of VE-cadherin cell contacts, persistence of F-actin stress fibers, and sustained phosphorylation of the ERM complex and activation of RhoA, suggesting a failure in endothelial barrier stabilization. The results suggest that Podxl has an essential role in the regulation of endothelial permeability by influencing the mechanisms involved in the restoration of endothelial barrier integrity after injury.

Vasculitis and Systemic Lupus Erythematous (SLE)

Vasculitis are a heterogeneous group of disorders characterized by inflammation of the blood vessels of different caliber and sometimes fibrinoid necrosis with vessel wall destruction [1]. Vasculitis are divided into cutaneous and systemic forms, primary and secondary to hypertension, immunosuppression therapy, metabolic complications. The classification is based on the affected vessel size (Table ​(Table1).1). They may have neurological manifestations at the onset and during the desease development. These are more common in systemic forms such as SLE and Nodose Polyarteritis (PAN). Table 1 Vasculitis: classification (Adapted from EULAR/PReS endorsed criteria for the classification of childhood vasculitis) 2006; 65:936-41 The Schonlein-Henoch purpura and Kawasaki disease, the most frequent vasculitisin childhood, rarely can have neurological disorders. There are forms of mild to moderate intensity like headache, irritability, mood disorders and behavioral and forms of severe as seizures and sensory disturbance up to coma. In the course of SLE, neuropsychiatric manifestations, headache and chorea are common, with an incidence of 20-40% (also 80% with cognitive disorders and asymptomatic alterations RMN). The neuropsychiatric manifestations involve 40-56% of children; headache the 22-64%; convulsions the 20-31%; chorea 4-10%; peripheral neuropathy 5-6%; myelopathy 1%. Heterogeneity in their neurological symptoms are important for prognostic purposes. In antiphospholipid syndrome, primary or secondary, the following are common: transient cerebral ischemia and ischemic stroke, memory loss, chorea, seizures, vision problems [2]. The PAN is a necrotizing vasculitis histo-pathological examination, rarely aneurysm, stenosis or occlusion (not caused by fibro-muscular dysplasia, or by other causes not inflammatory) artery of small and medium caliber. In addition, at least one of the following signs/symptoms: skin involvement (livedo, nodules or heart attacks); myalgia; hypertension; peripheral neuropathy (sensory or motor); renal involvement (proteinuria, haematuria, renal impairment). The primary central nervous system vasculitis is a brain vessels inflammation not associated with vasculitis of other organs. The classification is based on the vessel size: small (with normal angiography) and medium-large (progressive and non-progressive). This form, responsible for 40-60% of arterial ischemic stroke, affects 3-8/100.000 children/year. Symptoms are characterized by acute severe headache (80%), focal neurological deficit (78%), motor deficit (62%), cognitive disorders (54%), cranial nerve involvement (59%), seizures (small vessel vasculitis). Peripheral neuropathies are characteristic of the Churg-Strauss disease. The clinical diagnosis is often difficult (Table ​(Table22). Table 2 Vasculitis: diagnosis Neurological complications are diagnosed early because the treatment must be immediate and aggressive.

Systemic Vasculitis in Various Organs of 33 Rheumatoid Arthritis and 11 Progressive Systemic Sclerosis Patients – A Comparative Postmortem Study

Objective: The aim of this study was (1) to compare the prevalence and severity of Systemic Vasculitis (SV) in various organs of Rheumatoid Arthritis (RA) and of progressive Systemic Sclerosis (SSc) patients, (2) To determine the complications and lethal outcome caused by vasculitis in RA and SSc. Patients and Methods: Twelve organs (heart, lung, liver, spleen, kidneys, pancreas, gastrointestinal tract, adrenal glands, skeletal muscle, peripheral nerve, skin and brain) of 33 RA and of 11 SSc with SV were studied microscopically. RA and SSc were confirmed clinically according to the criteria of the American College of Rheumatology. The basic disease, the complications, and the lethal outcome caused by vasculitis were determined and analyzed retrospectively, reviewing the clinical and pathological reports, tissue samples, and the histological slides. The existence (prevalence) of vasculitis in various organs was determined based on the presence of vasculitis in blood vessels of different calibers. The severity of vasculitis in various organs was evaluated by semi-quantitative, visual estimation on a 0 to 3 plus scale (based on the number of involved vessels/light microscopic field x40). Results and Conclusions: SV was observed in all of 33 RA and 11 SSc patients with variable prevalence and severity. The average value of prevalence and severity/organ in SSc was appreciably higher than that of RA. In RA patients, not all investigated organs were involved with SV and the existence of blood vessels with vasculitis in each organ was different. In SSc patients SV was present in each of the investigated organs, but with different severity. In RA the heart, skeletal muscle, pancreas, lung, kidneys and gastrointestinal tract were most markedly involved, while in SSc the kidneys, spleen, lung, pancreas, heart and gastrointestinal tract were. The high prevalence of SV and the consecutive fibrosis in these organs identify the main targets of autoimmune processes in RA and SSc prior to the more visible skin involvement. The most markedly involved organs denote a favorable site for histological diagnosis of SV, for example skeletal muscle with peripheral nerve (sural nerve) or gastrointestinal tract in RA and the gastrointestinal tract in SSc. The course of the disease, more precisely mortality due to SV,

THE MECHANISMS OF REORGANIZATION OF BLOOD VESSELS OF MYOCARDIAL RIGHT ATRIA AT HEMODYNAMIC CHANGES

It was shown that pulmonary arterial valve stenosis moderate changes in hemodynamic parameters of patients lead to a change in the structure of cardiomyocyte and blood vessel. Strengthening of plastic processes, lead to hypertrophy and proliferation of endothelial cells as well as to increase of blood vessels' lumen diameter. Quite interesting is the fact that new capillaries formed mostly by intuscusseptive angiogenesis. In the same way new arteries are formed. Hemodynamic changes of heart right compartment accompanied by structural vascular and cardiomyocyte remodeling. In the later stages of disease vascular remodeling goes by the mechanism of intussusceptions forming vessels of different caliber.

Use of input impedance to determine changes in the resistance of arterial vessels at different levels in feline femoral bed.

In many studies, the functional state of vessels of different caliber was determined by fitting the lumped parameters of a mathematical model of the bed in order to fit the vascular input impedance (Z in) data. However, reliability of the results obtained in such a way remains uncertain. In this study, we employed a mathematical model with seven lumped parameters and Z in experimental data to analyze the distribution of resistance across the arterial bed of the hind limb in anesthetized cats, to test reliability of this distribution and to describe the process of ascending arterial dilation followed occlusion of iliac artery. The vascular bed was divided into three segments: large arteries, medium-sized arterial vessels and precapillary resistance vessels together with venous part of the bed. Based on the data of Z in measured in a wide frequency range (from 0 to 150 Hz) we showed that pharmacologically induced constriction and dilation of the arterial microvessels were reflected in the model by the changes in the resistance of distal precapillary vessels only, whereas the local constriction or dilation of femoral and iliac arteries as well as artificial stenosis of the femoral artery resulted exclusively in the changes of the resistance describing the state of large arteries. Using the input impedance method we could demonstrate and quantitatively describe the process of ascending arterial dilation during the post-occlusion (reactive) hyperemia. All these results prove that the model of vascular bed with seven lumped elements used in combination with input hydraulic impedance data can be an effective tool permitted to quantitatively analyze the functional state of arterial vessels of different caliber and to describe the changes in resistance of arterial vessels during vascular reactions.

Vasculitis: Etiopatogenia y Cuadro Clínico

Las vasculitis son un conjunto heterogéneo de entidades clínicas que comparten en común la afección inflamatoria de vasos sanguíneos de distinto calibre, con expresión clínica e histológica muy variada. Se ha planteado diferentes formas de clasificar a las vasculitis, basadas en parámetros diversos como el tamaño de los vasos afectados, la etiología probable o los criterios clínicos. Presentamos las tres que consideramos más representativas: la de Fauci, la de Lie y la del Consenso establecido en 1993 en Chapel Hill. La característica patológica más importante en las diferentes formas de vasculitis es la inflamación de los vasos sanguíneos con necrosis tisular y. en ocasiones, formación de granulomas. Fisiopatológicamente, estos fenómenos se traducen en daño y oclusión vascular, isquemia tisular, formación de aneurismas y, con menor frecuencia, ruptura vascular.

The Coronary Microcirculation in Health and Disease

Coronary blood flow is closely regulated to meet the changing metabolic demands of the working myocardium. Resistance of the coronary vasculature is determined by metabolic, myogenic, endothelial, and neural mechanisms. The influence of these control mechanisms varies throughout the coronary circulation, as they have dominant sites of action in vessels of different caliber. Coronary vascular resistance depends upon the coordinated response to these influences. Within a segment of the coronary circulation, resistance may be determined, for example, by competitive interaction between neural vasoconstriction and metabolic vasodilation. Such a system in which control occurs through multiple mechanisms with varying effects allows for precise control of coronary blood flow. This system also provides protection against dysfunction of a single control mechanism. If one fails, other control mechanisms can compensate for that loss of function. Thus, adequate delivery of oxygen and nutrients can be maintained despite potential dysfunction and large fluctuations in metabolic demands of the myocardium. In disease states, these regulatory mechanisms may also fail, and endothelial dysfunction is commonly seen in the setting of cardiac disease. Optimal cardioprotective therapies must target the coronary microcirculation and cardiac myocytes in tandem. Similarly, reversal of cardiac dysfunction requires concomitant amelioration of coronary microvascular dysfunction.