RESUMEN
Finger vein recognition methods, as emerging biometric technologies, have attracted increasing attention in identity verification due to their high accuracy and live detection capabilities. However, as privacy protection awareness increases, traditional centralized finger vein recognition algorithms face privacy and security issues. Federated learning, a distributed training method that protects data privacy without sharing data across endpoints, is gradually being promoted and applied. Nevertheless, its performance is severely limited by heterogeneity among datasets. To address these issues, this paper proposes a dual-decoupling personalized federated learning framework for finger vein recognition (DDP-FedFV). The DDP-FedFV method combines generalization and personalization. In the first stage, the DDP-FedFV method implements a dual-decoupling mechanism involving model and feature decoupling to optimize feature representations and enhance the generalizability of the global model. In the second stage, the DDP-FedFV method implements a personalized weight aggregation method, federated personalization weight ratio reduction (FedPWRR), to optimize the parameter aggregation process based on data distribution information, thereby enhancing the personalization of the client models. To evaluate the performance of the DDP-FedFV method, theoretical analyses and experiments were conducted based on six public finger vein datasets. The experimental results indicate that the proposed algorithm outperforms centralized training models without increasing communication costs or privacy leakage risks.
Asunto(s)
Algoritmos , Dedos , Venas , Humanos , Dedos/irrigación sanguínea , Dedos/fisiología , Venas/fisiología , Aprendizaje Automático , Identificación Biométrica/métodosRESUMEN
Aqueous humor (AQH) is a transparent fluid with characteristics similar to those of the interstitial fluid, which fills the eyeball posterior and anterior chambers and circulates in them from the sites of production to those of drainage. The AQH volume and pressure homeostasis is essential for the trophism of the ocular avascular tissues and their normal structure and function. Different AQH outflow pathways exist, including a main pathway, quite well defined anatomically and referred to as the conventional pathway, and some accessory pathways, more recently described and still not fully morphofunctionally understood, generically referred to as unconventional pathways. The conventional pathway is based on the existence of a series of conduits starting with the trabecular meshwork and Schlemm's Canal and continuing with a system of intrascleral and episcleral venules, which are tributaries to veins of the anterior segment of the eyeball. The unconventional pathways are mainly represented by the uveoscleral pathway, in which AQH flows through clefts, interstitial conduits located in the ciliary body and sclera, and then merges into the aforementioned intrascleral and episcleral venules. A further unconventional pathway, the lymphatic pathway, has been supported by the demonstration of lymphatic microvessels in the limbal sclera and, possibly, in the uvea (ciliary body, choroid) as well as by the ocular glymphatic channels, present in the neural retina and optic nerve. It follows that AQH may be drained from the eyeball through blood vessels (TM-SC pathway, US pathway) or lymphatic vessels (lymphatic pathway), and the different pathways may integrate or compensate for each other, optimizing the AQH drainage. The present review aims to define the state-of-the-art concerning the structural organization and the functional anatomy of all the AQH outflow pathways. Particular attention is paid to examining the regulatory mechanisms active in each of them. The new data on the anatomy and physiology of AQH outflow pathways is the key to understanding the pathophysiology of AQH outflow disorders and could open the way for novel approaches to their treatment.
Asunto(s)
Humor Acuoso , Sistema Linfático , Humor Acuoso/fisiología , Humor Acuoso/metabolismo , Humanos , Sistema Linfático/fisiología , Esclerótica/irrigación sanguínea , Malla Trabecular/metabolismo , Vasos Linfáticos/fisiología , Venas/fisiología , Úvea , Animales , Presión Intraocular/fisiología , Linfa/fisiología , Cuerpo Ciliar/irrigación sanguínea , Cuerpo Ciliar/metabolismoRESUMEN
In bivalves and gastropods, ventricle contraction causes a negative pressure in the auricles and increases venous return from the afferent oblique vein (AOV): the constant-volume (CV) mechanism. The flow in the AOV should be a pulsative flow synchronized with the ventricular contraction. The flow in the heart and adjacent vessels of Mytilus galloprovincialis were measured by magnetic resonance imaging to confirm this hypothesis. Under a regular heartbeat, pulsative flows in the AOV and branchial vessels (BVs) were almost completely synchronized with the flow in the aorta, while filling of the ventricle was in the opposite phase. Flows in the BVs were directed to the posterior direction, and a pair of BVs in the gill axes (the efferent BVs) were connected to the AOV. Based on the images of the whole pathway of the AOV in an oblique slice, we confirmed that haemolymph flow was evoked from the efferent BVs and flow into the ventricle via the auricle was completed in a single heartbeat. Therefore, the walls of the AOV and BVs could resist negative transmural pressure caused by the ventricular contraction. In conclusion, the auricle, the AOV and the BVs, including the gill filaments, act as a suction pump. The pulsative venous return is driven by the negative pressure of the AOV as in the CV mechanism, and the negative pressure in the efferent BVs could draw haemolymph from the sinus via the gill and the afferent BVs. Therefore, Mytilus can start and stop its heartbeat as necessary.
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Mytilus , Animales , Mytilus/fisiología , Corazón/fisiología , Venas/fisiología , Branquias/fisiología , Imagen por Resonancia Magnética , Región Branquial/fisiología , Hemolinfa/fisiología , Flujo Pulsátil/fisiologíaRESUMEN
Mean circulatory filling pressure, venous return curve, and Guyton's graphical analysis are basic concepts in cardiovascular physiology. However, some medical students may not know how to view and interpret or understand them adequately. To deepen students' understanding of the graphical analysis, in place of having to perform live animal experiments, we developed an interactive cardiovascular simulator, as a self-learning tool, as a web application. The minimum closed-loop model consisted of a ventricle, an artery, resistance, and a vein, excluding venous resistance. The simulator consists of three modules: setting (parameters and simulation modes), calculation, and presentation. In the setting module, the user can interactively customize model parameters, compliances, resistance, Emax of the ventricular contractility, total blood volume, and unstressed volume. The hemodynamics are calculated in three phases: filling (late diastole), ejection (systole), and flow (early diastole). In response to the user's settings, the simulator graphically presents the hemodynamics: the pressure-volume relations of the artery, vein, and ventricle, the venous return curves, and the stroke volume curves. The mean filling pressure is calculated at approximately 7 mmHg at the initial setting. The venous return curves, linear and concave, are dependent on the venous compliance. The hemodynamic equilibrium point is marked on the crossing point of venous return curve and the stroke volume curve. Users can interactively do discovery learning, and try and confirm their interests and get their questions answered about hemodynamic concepts by using the simulator.
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Hemodinámica , Venas , Animales , Humanos , Venas/fisiología , Volumen Sistólico , Presión Sanguínea/fisiología , Gasto Cardíaco/fisiologíaRESUMEN
There is increasing interest in how immune cells in the meninges-the membranes that surround the brain and spinal cord-contribute to homeostasis and disease in the central nervous system1,2. The outer layer of the meninges, the dura mater, has recently been described to contain both innate and adaptive immune cells, and functions as a site for B cell development3-6. Here we identify organized lymphoid structures that protect fenestrated vasculature in the dura mater. The most elaborate of these dural-associated lymphoid tissues (DALT) surrounded the rostral-rhinal confluence of the sinuses and included lymphatic vessels. We termed this structure, which interfaces with the skull bone marrow and a comparable venous plexus at the skull base, the rostral-rhinal venolymphatic hub. Immune aggregates were present in DALT during homeostasis and expanded with age or after challenge with systemic or nasal antigens. DALT contain germinal centre B cells and support the generation of somatically mutated, antibody-producing cells in response to a nasal pathogen challenge. Inhibition of lymphocyte entry into the rostral-rhinal hub at the time of nasal viral challenge abrogated the generation of germinal centre B cells and class-switched plasma cells, as did perturbation of B-T cell interactions. These data demonstrate a lymphoid structure around vasculature in the dura mater that can sample antigens and rapidly support humoral immune responses after local pathogen challenge.
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Duramadre , Inmunidad Humoral , Tejido Linfoide , Venas , Administración Intranasal , Antígenos/administración & dosificación , Antígenos/inmunología , Médula Ósea/inmunología , Sistema Nervioso Central/irrigación sanguínea , Sistema Nervioso Central/inmunología , Duramadre/irrigación sanguínea , Duramadre/inmunología , Centro Germinal/citología , Centro Germinal/inmunología , Vasos Linfáticos/inmunología , Tejido Linfoide/irrigación sanguínea , Tejido Linfoide/inmunología , Células Plasmáticas/inmunología , Cráneo/irrigación sanguínea , Linfocitos T/inmunología , Venas/fisiología , Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Animales , Ratones , Anciano de 80 o más AñosRESUMEN
Vascular diseases of the legs are highly prevalent and constitute an important part of medical curricula. The understanding of these diseases relies on strongly interwoven aspects of vascular physiology and vascular medicine. We aimed to connect these within a horizontally integrated laboratory class on vascular physiology of the leg that was designed in cooperation between the departments of physiology and vascular surgery. Conceptually, we applied examination techniques of vascular medicine to visualize physiological parameters that are altered by the most frequent diseases. This facilitates integrative discussions on malfunctions, trains diagnostic skills, and bridges to vascular medicine. In four experiments, we use oscillometry and impedance venous occlusion plethysmography to address key aspects of the arterial and venous system of the legs: 1) arterial pulse wave, 2) arterial systolic blood pressure, 3) venous capacitance and venous outflow, and 4) reactive hyperemia. After the experiments, physiological vascular function, the associated diseases, their impact on the recorded parameters, and diagnostic options are discussed. To allow reproduction, we describe the course structure and the experimental setup in detail. We present the experimental data of a cohort of medical students and document learning success and student satisfaction. All experiments were feasible and provided robust data on physiologically and clinically relevant vascular functions. The activity was perceived positively by the students and led to a substantial improvement of knowledge. With this work, we offer a template for reproduction or variation of a proven concept of horizontally integrated teaching of vascular physiology of the leg.NEW & NOTEWORTHY This article presents an integrative laboratory class on vascular physiology bridging to vascular medicine. The four experiments rely on oscillometry and venous occlusion plethysmography. We describe in detail this new class regarding structure, experimental setup, and experimental procedure, and we give insight into the applied materials. Moreover, we present the experimental data of 74 students and a quantitative evaluation of the students' learning success and acceptance.
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Cardiología , Fisiología , Humanos , Pletismografía/métodos , Venas/fisiología , Presión SanguíneaRESUMEN
Tissue factor (TF) is an evolutionarily conserved protein necessary for initiation of hemostasis. Zebrafish have two copies of the tissue factor gene (f3a and f3b) as the result of an ancestral teleost fish duplication event (so called ohnologs). In vivo physiologic studies of TF function have been difficult given early lethality of TF knockout in the mouse. We used genome editing to produce knockouts of both f3a and f3b in zebrafish. Since ohnologs arose through sub- or neofunctionalization, they can unmask unknown functions of non-teleost genes and could reveal whether mammalian TF has developmental functions distinct from coagulation. Here we show that a single copy of either f3a or f3b is necessary and sufficient for normal lifespan. Complete loss of TF results in lethal hemorrhage by 2-4 months despite normal embryonic and vascular development. Larval vascular endothelial injury reveals predominant roles for TFa in venous circulation and TFb in arterial circulation. Finally, we demonstrate that loss of TF predisposes to a stress-induced cardiac tamponade independent of its role in fibrin formation. Overall, our data suggest partial subfunctionalization of TFa and TFb. This multigenic zebrafish model has the potential to facilitate study of the role of TF in different vascular beds.
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Duplicación de Gen , Hemostasis , Tromboplastina , Animales , Ratones , Larva , Tromboplastina/genética , Tromboplastina/fisiología , Pez Cebra/genética , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Hemostasis/genética , Venas/fisiología , Arterias/fisiologíaRESUMEN
OBJECTIVE: Immature arteriovenous fistula (AVF) is a critical problem in patients with chronic kidney disease (CKD) after creation. Exercise with 30% maximum voluntary contraction (MVC) encourages vascular functions in other populations. It is unknown which exercise type is superior on maturation in the CKD population. We compare effects of isometric (ISM) and isotonic (IST) hand exercise training, both at 30% MVC, on AVF maturation and grip strength in patients with CKD. METHODS: Fifty patients with CKD were randomized into the ISM program or IST program (25 per group). Each group performed exercise program at intensity of 30% MVC every day for 10 weeks. Cephalic vein (CV) and brachial artery diameters, brachial blood flows, and grip strength were measured at weeks 0, 2, 6, and 10 of the program. The number of patients meeting clinical and ultrasound maturation were evaluated at weeks 2, 6, and 10. RESULTS: At weeks 6 and 10 of the programs, the ISM group had greater CV diameters (week 6, 7.1 ± 1.2 vs 6.2 ± 1.0 mm; week 10, 7.1 ± 1.0 vs 6.2 ± 1.1 mm) than the IST group. Compared with the IST group, the ISM group had a higher number of patients meeting ultrasound maturation at weeks 2 (IST/ISM, 8/2), 6 (IST/ISM, 16/8), and 10 (IST/ISM, 21/12), and clinical maturation at week 10 (IST/ISM, 25/18). No adverse events were observed throughout the study. CONCLUSIONS: At 30% MVC, ISM is more effective at promoting increases in CV diameter and maturation than IST. Both exercise types are feasible and safe for patients with CKD after AVF creation.
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Derivación Arteriovenosa Quirúrgica/rehabilitación , Terapia por Ejercicio/métodos , Mano/fisiología , Diálisis Renal/métodos , Insuficiencia Renal Crónica/terapia , Anciano , Mano/irrigación sanguínea , Fuerza de la Mano , Humanos , Masculino , Persona de Mediana Edad , Arteria Radial/diagnóstico por imagen , Arteria Radial/fisiología , Arteria Radial/cirugía , Resultado del Tratamiento , Ultrasonografía Doppler , Grado de Desobstrucción Vascular/fisiología , Venas/diagnóstico por imagen , Venas/fisiología , Venas/cirugíaRESUMEN
A method motivated by the eye's aqueous veins is described for the imaging and strain calculation within soft biological tissues. A challenge to the investigation of the biomechanics of the aqueous vein-perilimbal sclera tissue complex is resolution of tissue deformations as a function of intraocular pressure and the subsequent calculation of strain (a normalized measure of deformation). The method involves perfusion of the eye with a contrast agent during conduction of non-invasive, optical resolution photoacoustic microscopy. This imaging technique permits three-dimensional displacement measurements of tracked points on the inner walls of the veins which are used in a finite element model to determine the corresponding strains. The methods are validated against two standard strain measurement methods. Representative porcine globe perfusion experiments are presented that demonstrate the power of the method to determine complex strain fields in the veins dependent on intraocular pressure as well as vein anatomy. In these cases, veins are observed to move radially outward during increases in intraocular pressure and to possess significant spatial strain variation, possibly influenced by their branching patterns. To the authors' knowledge, these are the only such quantitative, data driven, calculations of the aqueous vein strains available in the open literature.
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Imagenología Tridimensional/métodos , Técnicas Fotoacústicas/métodos , Esclerótica/fisiología , Venas/fisiología , Animales , Fenómenos Biomecánicos/fisiología , Biofisica/métodos , Análisis de Elementos Finitos , Presión Intraocular/fisiología , Disco Óptico/fisiología , Estrés Mecánico , Porcinos , Tonometría Ocular/métodosRESUMEN
BACKGROUND: Previous studies have established the role of various tissue compartments in the kinetics of inhaled anesthetic uptake and elimination. The role of normal lungs in inhaled anesthetic kinetics is less understood. In juvenile pigs with normal lungs, the authors measured desflurane and sevoflurane washin and washout kinetics at three different ratios of alveolar minute ventilation to cardiac output value. The main hypothesis was that the ventilation/perfusion ratio (VA/Q) of normal lungs influences the kinetics of inhaled anesthetics. METHODS: Seven healthy pigs were anesthetized with intravenous anesthetics and mechanically ventilated. Each animal was studied under three different VA/Q conditions: normal, low, and high. For each VA/Q condition, desflurane and sevoflurane were administered at a constant, subanesthetic inspired partial pressure (0.15 volume% for sevoflurane and 0.5 volume% for desflurane) for 45 min. Pulmonary arterial and systemic arterial blood samples were collected at eight time points during uptake, and then at these same times during elimination, for measurement of desflurane and sevoflurane partial pressures. The authors also assessed the effect of VA/Q on paired differences in arterial and mixed venous partial pressures. RESULTS: For desflurane washin, the scaled arterial partial pressure differences between 5 and 0 min were 0.70 ± 0.10, 0.93 ± 0.08, and 0.82 ± 0.07 for the low, normal, and high VA/Q conditions (means, 95% CI). Equivalent measurements for sevoflurane were 0.55 ± 0.06, 0.77 ± 0.04, and 0.75 ± 0.08. For desflurane washout, the scaled arterial partial pressure differences between 0 and 5 min were 0.76 ± 0.04, 0.88 ± 0.02, and 0.92 ± 0.01 for the low, normal, and high VA/Q conditions. Equivalent measurements for sevoflurane were 0.79 ± 0.05, 0.85 ± 0.03, and 0.90 ± 0.03. CONCLUSIONS: Kinetics of inhaled anesthetic washin and washout are substantially altered by changes in the global VA/Q ratio for normal lungs.
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Desflurano/administración & dosificación , Desflurano/sangre , Sevoflurano/administración & dosificación , Sevoflurano/sangre , Relación Ventilacion-Perfusión/fisiología , Anestésicos por Inhalación/administración & dosificación , Anestésicos por Inhalación/sangre , Animales , Animales Recién Nacidos , Arterias/efectos de los fármacos , Combinación de Medicamentos , Femenino , Cinética , Masculino , Porcinos , Venas/efectos de los fármacos , Venas/fisiología , Relación Ventilacion-Perfusión/efectos de los fármacosRESUMEN
The flow patterns of red blood cells through the spleen are intimately linked to clearance of senescent RBCs, with clearance principally occurring within the open flow through the red pulp and slits of the venous sinus system that exists in humans, rats, and dogs. Passage through interendothelial slits (IESs) of the sinus has been shown by MacDonald et al. (Microvasc Res 33:118-134, 1987) to be mediated by the caliber, i.e., slit opening width, of these slits. IES caliber within a given slit of a given sinus section has been shown to operate in an asynchronous manner. Here, we describe a model and simulation results that demonstrate how the supporting forces exerted on the sinus by the reticular meshwork of the red pulp, combined with asymmetrical contractility of stress fibers within the endothelial cells comprising the sinus, describe this vital and intriguing behavior. These results shed light on the function of the sinus slits in species such as humans, rats, and dogs that possess sinusoidal sinuses. Instead of assuming a passive mechanical filtering mechanism of the IESs, our proposed model provides a mechanically consistent explanation for the dynamically modulated IES opening/filtering mechanism observed in vivo. The overall perspective provided is also consistent with the view that IES passage serves as a self-protective mechanism in RBC vesiculation and inclusion removal.
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Células Endoteliales/fisiología , Eritrocitos/fisiología , Hemorreología , Bazo/irrigación sanguínea , Venas/fisiología , Simulación por Computador , Células Endoteliales/ultraestructura , Eritrocitos/ultraestructura , Humanos , Cinética , Modelos Biológicos , Presión , Bazo/ultraestructura , Estrés Mecánico , Venas/ultraestructuraRESUMEN
Defining the hemodynamic response to volume therapy is integral to managing critically ill patients with acute circulatory failure, especially in the absence of cardiac index (CI) measurement. This study aimed at investigating whether changes in central venous-to-arterial CO2 difference (Δ-ΔPCO2) and central venous oxygen saturation (ΔScvO2) induced by volume expansion (VE) are reliable parameters to define fluid responsiveness in sedated and mechanically ventilated septic patients. We prospectively studied 49 critically ill septic patients in whom VE was indicated because of circulatory failure and clinical indices. CI, ΔPCO2, ScvO2, and oxygen consumption (VO2) were measured before and after VE. Responders were defined as patients with a > 10% increase in CI (transpulmonary thermodilution) after VE. We calculated areas under the receiver operating characteristic curves (AUCs) for Δ-ΔPCO2, ΔScvO2, and changes in CI (ΔCI) after VE in the whole population and in the subgroup of patients with an increase in VO2 (ΔVO2) ≤ 10% after VE (oxygen-supply independency). Twenty-five patients were fluid responders. In the whole population, Δ-ΔPCO2 and ΔScvO2 were significantly correlated with ΔCI after VE (r = - 0.30, p = 0.03 and r = 0.42, p = 0.003, respectively). The AUCs for Δ-ΔPCO2 and ΔScvO2 to define fluid responsiveness (increase in CI > 10% after VE) were 0.76 (p < 0.001) and 0.68 (p = 0.02), respectively. In patients with ΔVO2 ≤ 10% (n = 36) after VE, the correlation between ΔScvO2 and ΔCI was 0.62 (p < 0.001), and between Δ-ΔPCO2 and ΔCI was - 0.47 (p = 0.004). The AUCs for Δ-ΔPCO2 and ΔScvO2 were 0.83 (p < 0.001) and 0.73 (p = 0.006), respectively. In these patients, Δ-ΔPCO2 ≤ -37.5% after VE allowed the categorization between responders and non-responders with a positive predictive value of 100% and a negative predictive value of 60%. In sedated and mechanically ventilated septic patients with no signs of tissue hypoxia (oxygen-supply independency), Δ-ΔPCO2 is a reliable parameter to define fluid responsiveness.
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Arterias/fisiología , Biomarcadores/análisis , Dióxido de Carbono/metabolismo , Fluidoterapia/métodos , Choque Séptico/terapia , Venas/fisiología , Anciano , Enfermedad Crítica/terapia , Femenino , Hemodinámica/fisiología , Humanos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud/métodos , Consumo de Oxígeno/fisiología , Presión Parcial , Estudios ProspectivosRESUMEN
Arteries and veins form in a stepwise process that combines vasculogenesis and sprouting angiogenesis. Despite extensive data on the mechanisms governing blood vessel assembly at the single-cell level, little is known about how collective cell migration contributes to the organization of the balanced distribution between arteries and veins. Here, we use an endothelial-specific zebrafish reporter, arteriobow, to label small cohorts of arterial cells and trace their progeny from early vasculogenesis throughout arteriovenous remodeling. We reveal that the genesis of arteries and veins relies on the coordination of 10 types of collective cell dynamics. Within these behavioral categories, we identify a heterogeneity of collective cell motion specific to either arterial or venous remodeling. Using pharmacological blockade, we further show that cell-intrinsic Notch signaling and cell-extrinsic blood flow act as regulators in maintaining the heterogeneity of collective endothelial cell behavior, which, in turn, instructs the future territory of arteriovenous remodeling.
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Arterias/fisiología , Rastreo Celular , Células Endoteliales/citología , Remodelación Vascular/fisiología , Venas/fisiología , Animales , Animales Modificados Genéticamente , Células Clonales , Células Endoteliales/metabolismo , Genes Reporteros , Receptores Notch/metabolismo , Flujo Sanguíneo Regional , Reología , Transducción de Señal , Pez CebraRESUMEN
Personalized tissue engineered vascular grafts are a promising advanced therapy medicinal product alternative to autologous or synthetic vascular grafts utilized in blood vessel bypass or replacement surgery. We hypothesized that an individualized tissue engineered vein (P-TEV) would make the body recognize the transplanted blood vessel as autologous, decrease the risk of rejection and thereby avoid lifelong treatment with immune suppressant medication as is standard with allogenic organ transplantation. To individualize blood vessels, we decellularized vena cava from six deceased donor pigs and tested them for cellular removal and histological integrity. A solution with peripheral blood from the recipient pigs was used for individualized reconditioning in a perfusion bioreactor for seven days prior to transplantation. To evaluate safety and functionality of the individualized vascular graft in vivo, we transplanted reconditioned porcine vena cava into six pigs and analyzed histology and patency of the graft at different time points, with three pigs at the final endpoint 4-5 weeks after surgery. Our results showed that the P-TEV was fully patent in all animals, did not induce any occlusion or stenosis formation and we did not find any signs of rejection. The P-TEV showed rapid recellularization in vivo with the luminal surface covered with endothelial cells. In summary, the results indicate that P-TEV is functional and have potential for use as clinical transplant grafts.
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Prótesis Vascular , Prueba de Estudio Conceptual , Ingeniería de Tejidos , Venas/fisiología , Animales , Porcinos , Grado de Desobstrucción Vascular , Venas/trasplante , Venas/ultraestructuraRESUMEN
BACKGROUND: This study aims to determine the phlebotomy and procedural outcomes using a vein assessment tool (VAT) in Double Dose Platelet (DDP) collections by apheresis. METHODS: VAT was based on assessing vein visibility, palpation and size with maximum score of 12 and the least being 0 and the scores were graded as adequate and inadequate. A vein-viewer was used for studying cubital vein patterns (type 1-5). Phlebotomy outcome was defined based on need for re-puncture. Procedural outcomes in terms of target yield attained and RBC reinfusion completed. Chi square test and Mann- Whitney U test were used to assess the vein score and pattern against phlebotomy and procedural outcome. RESULTS: Out of 200 DDP collections, the phlebotomy was successful in 88 % with good procedural outcome in 94 % donations. The cut off in VAT scores for successful phlebotomy was ≥8 (AUC: 70 %). Median vein scores of the arm selected for phlebotomy was 9 and graded adequate in 154 (77 %) donations.Odds for successful phlebotomy was 3.7 times higher when donors had an adequate VAT grades(p = 0.003). Procedural outcomes was favourable when at least one arm had adequate VAT grade when compared to both arms being inadequate (98 % vs 82 %; p < 0.001). Phlebotomy failure was more with first time apheresis donors than repeat apheresis donors (p = 0.014). CONCLUSION: This study indicated that a VAT score with a cut off of ≥8 had better phlebotomy and procedural outcomes in DDP collections and that donor with at least one arm having the VAT score of ≥8 are preferred for DDP collections.
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Eliminación de Componentes Sanguíneos/métodos , Plaquetas/citología , Plaquetoferesis/instrumentación , Plaquetoferesis/métodos , Venas/anatomía & histología , Venas/fisiología , Adulto , Transfusión de Componentes Sanguíneos/instrumentación , Transfusión de Componentes Sanguíneos/métodos , Donantes de Sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Flebotomía , Estudios Prospectivos , Resultado del Tratamiento , Adulto JovenRESUMEN
The measurement of vascular function in isolated vessels has revealed important insights into the structural, functional, and biomechanical features of the normal and diseased cardiovascular system and has provided a molecular understanding of the cells that constitutes arteries and veins and their interaction. Further, this approach has allowed the discovery of vital pharmacological treatments for cardiovascular diseases. However, the expansion of the vascular physiology field has also brought new concerns over scientific rigor and reproducibility. Therefore, it is appropriate to set guidelines for the best practices of evaluating vascular function in isolated vessels. These guidelines are a comprehensive document detailing the best practices and pitfalls for the assessment of function in large and small arteries and veins. Herein, we bring together experts in the field of vascular physiology with the purpose of developing guidelines for evaluating ex vivo vascular function. By using this document, vascular physiologists will have consistency among methodological approaches, producing more reliable and reproducible results.
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Arterias/fisiología , Vasoconstricción/fisiología , Vasodilatación/fisiología , Venas/fisiología , Animales , Endotelio Vascular/fisiología , Microscopía/métodos , Miografía/métodos , Reproducibilidad de los ResultadosRESUMEN
The endothelial glycocalyx is a dynamic structure integral to blood vessel hemodynamics and capable of tightly regulating a range of biological processes (ie, innate immunity, inflammation, and coagulation) through dynamic changes in its composition of the brush structure. Evaluating the specific roles of the endothelial glycocalyx under a range of pathophysiologic conditions has been a challenge in vitro as it is difficult to generate functional glycocalyces using commonly employed 2D cell culture models. We present a new multi-height microfluidic platform that promotes the growth of functional glycocalyces by eliciting unique shear stress forces over a continuous human umbilical vein endothelial cell monolayer at magnitudes that recapitulate the physical environment in arterial, capillary and venous regions of the vasculature. Following 72 hours of shear stress, unique glycocalyx structures formed within each region that were distinct from that observed in short (3 days) and long-term (21 days) static cell culture. The model demonstrated glycocalyx-specific properties that match the characteristics of the endothelium in arteries, capillaries and veins, with respect to surface protein expression, platelet adhesion, lymphocyte binding and nanoparticle uptake. With artery-to-capillary-to-vein transition on a continuous endothelial monolayer, this in vitro platform is an improved system over static cell culture for more effectively studying the role of the glycocalyx in endothelial biology and disease.
Asunto(s)
Arterias/fisiología , Capilares/fisiología , Glicocálix/química , Glicocálix/metabolismo , Células Endoteliales de la Vena Umbilical Humana/fisiología , Estrés Mecánico , Venas/fisiología , Hemodinámica , Células Endoteliales de la Vena Umbilical Humana/citología , Humanos , Microfluídica , Resistencia al CorteRESUMEN
Extracorporeal membrane oxygenation (ECMO) support has a high incidence of both bleeding and thrombotic complications. Despite clear differences in patient characteristics and pathologies between veno-venous (VV) and veno-arterial (VA) ECMO support, anticoagulation practices are often the same across modalities. Moreover, there is very little data on their respective coagulation profiles and comparisons of thrombin generation in these patients. This study compares the coagulation profile and thrombin generation between patients supported with either VV and VA ECMO. A prospective cohort study of patients undergoing VA and VV ECMO at an Intensive care department of a university hospital and ECMO referral centre. In addition to routine coagulation testing and heparin monitoring per unit protocol, thromboelastography (TEG), multiplate aggregometry (MEA), calibrated automated thrombinography (CAT) and von-Willebrand's activity (antigen and activity ratio) were sampled second-daily for 1 week, then weekly thereafter. VA patients had significantly lower platelets counts, fibrinogen, anti-thrombin and clot strength with higher d-dimer levels than VV patients, consistent with a more pronounced consumptive coagulopathy. Thrombin generation was higher in VA than VV patients, and the heparin dose required to suppress thrombin generation was lower in VA patients. There were no significant differences in total bleeding or thrombotic event rates between VV and VA patients when adjusted for days on extracorporeal support. VA patients received a lower median daily heparin dose 8500 IU [IQR 2500-24000] versus VV 28,800 IU [IQR 17,300-40,800.00]; < 0.001. Twenty-eight patients (72%) survived to hospital discharge; comprising 53% of VA patients and 77% of VV patients. Significant differences between the coagulation profiles of VA and VV patients exist, and anticoagulation strategies for patients of these modalities should be different. Further research into the development of tailored anticoagulation strategies that include the mode of ECMO support need to be completed.
Asunto(s)
Arterias/fisiología , Coagulación Sanguínea/fisiología , Oxigenación por Membrana Extracorpórea , Hemostasis/fisiología , Trombina/metabolismo , Venas/fisiología , Adulto , Anticoagulantes/farmacología , Automatización , Coagulación Sanguínea/efectos de los fármacos , Oxigenación por Membrana Extracorpórea/efectos adversos , Factor Xa/metabolismo , Femenino , Hemorragia/etiología , Hemostasis/efectos de los fármacos , Heparina/farmacología , Humanos , Masculino , Persona de Mediana Edad , Tiempo de Tromboplastina Parcial , TromboelastografíaRESUMEN
Sepsis and septic shock remain the leading cause of death in intensive care units. Despite significant improvements in sepsis management, mortality still ranges between 20 and 30%. Novel treatment approaches in order to reduce sepsis-related multiorgan failure and death are urgently needed. Robust animal models allow for one or multiple treatment approaches as well as for testing their effect on physiological and molecular parameters. In this article, a simple animal model is presented. First, general anesthesia is induced in animals either with the use of volatile or by intraperitoneal anesthesia. After placement of an intravenous catheter (tail vein), tracheostomy, and insertion of an intraarterial catheter (tail artery), mechanical ventilation is started. Baseline values of mean arterial blood pressure, arterial blood oxygen saturation, and heart rate are recorded. The injection of lipopolysaccharides (1 milligram/kilogram body weight) dissolved in phosphate-buffered saline induces a strong and reproducible inflammatory response via the toll-like receptor 4. Fluid corrections as well as the application of norepinephrine are performed based on well-established protocols. The animal model presented in this article is easy to learn and strongly oriented towards clinical sepsis treatment in an intensive care unit with sedation, mechanical ventilation, continuous blood pressure monitoring, and repetitive blood sampling. Also, the model is reliable, allowing for reproducible data with a limited number of animals in accordance with the 3R (reduce, replace, refine) principles of animal research. While animal experiments in sepsis research cannot easily replaced, repetitive measurements allow for a reduction of animals and keeping septic animals anesthetized diminishes suffering.