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1.
Khirurgiia (Mosk) ; (1): 69-76, 2021.
Artigo em Russo | MEDLINE | ID: mdl-33395515

RESUMO

OBJECTIVE: To clarify the role of clinical anatomy of foot and ankle perforator veins (PV) in surgical treatment of varicose vein disease. MATERIAL AND METHODS: Anatomy of foot and ankle PV was assessed in 50 amputated lower extremities by anatomical dissection. RESULTS: There were 4-6 PVs at the medial surface of the foot. These veins connected medial marginal vein and vv. plantaris medialis (VPM). There were 2-3 PVs at the lateral surface of the foot. These veins connected lateral marginal vein and vv. plantaris lateralis (VPL). All PVs on the lateral surface of the foot constitute the neurovascular bundles. PVs flowing into vv. dorsalis pedis are localized on the medial surface of the medial marginal vein at the level of the ankle base. In most cases, we found an arterial branch nearby at the subfascial level. In anterior part of the plantar surface of the foot, we distinguished 4-5 small PVs (~1 mm) flowing into vv. digitales plantares through the commissural orifices of the aponeurosis. There were 6-9 vessels (~1 mm) along the fascial aponeurotic septa. These vessels connected superficial plantar venous network and plantar veins. Small arterial branch was found almost in all cases near these veins. Noteworthy is the area where the plantar veins lie on the quadratus plantae and are covered by a leaf of deep plantar fascia. This anatomy is similar to topography of posterior tibial veins. CONCLUSION: Foot perforator veins constitute the neurovascular bundles as a rule. Plantar vein topography and their relationship with PV confirm an existence of muscular-venous pump of the foot.


Assuntos
Tornozelo/irrigação sanguínea , Aponeurose , Pé/irrigação sanguínea , Fluxo Sanguíneo Regional/fisiologia , Veia Safena/anatomia & histologia , Varizes , Tornozelo/fisiopatologia , Aponeurose/irrigação sanguínea , Dissecação , Veia Femoral/anatomia & histologia , Veia Femoral/fisiopatologia , Pé/fisiopatologia , Humanos , Veia Safena/fisiopatologia , Varizes/diagnóstico , Varizes/fisiopatologia , Varizes/cirurgia
2.
Angiology ; 72(1): 9-15, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32757767

RESUMO

The endothelium plays a crucial role in maintaining cardiovascular homeostasis. Shear stress generated by flowing blood regulates the release of substances that provide adequate tissue perfusion. The extent of damage to endothelial cells depends on locally disturbed shear stress caused by the deteriorated flow. Patients with heart failure have reduced cardiac output, which results in reduced blood flow and negative shear stress. Reduced shear stress also affects microcirculation and reduces tissue perfusion. Consequently, the production of free oxygen radicals is increased and bioavailability of nitric oxide is additionally decreased. Therefore, endothelial dysfunction is involved in the progression of heart failure and cardiovascular events. Left ventricular assist devices (LVAD) are used for the treatment of patients with advanced heart failure. Older pulsatile flow LVADs were mostly substituted by continuous-flow LVADs (cf-LVADs). Despite the advantages of the cf-LVADs, the loss of pulsatility leads to different complications on the micro- and macrovascular levels. One of the pathogenetic mechanisms of cardiovascular complications with cf-LVADs may be endothelial dysfunction, which after the implantation of the device does not improve and may even deteriorate. In contrast, the pulsatile pattern of LVADs on blood flow could preserve endothelial function.


Assuntos
Endotélio Vascular/fisiopatologia , Coração Auxiliar , Doença da Artéria Coronariana/fisiopatologia , Circulação Coronária/fisiologia , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/terapia , Humanos , Inflamação/fisiopatologia , Fluxo Pulsátil/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Estresse Mecânico
3.
Nat Commun ; 11(1): 5209, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-33060602

RESUMO

Chronic high-thoracic and cervical spinal cord injury (SCI) results in a complex phenotype of cardiovascular consequences, including impaired left ventricular (LV) contractility. Here, we aim to determine whether such dysfunction manifests immediately post-injury, and if so, whether correcting impaired contractility can improve spinal cord oxygenation (SCO2), blood flow (SCBF) and metabolism. Using a porcine model of T2 SCI, we assess LV end-systolic elastance (contractility) via invasive pressure-volume catheterization, monitor intraparenchymal SCO2 and SCBF with fiberoptic oxygen sensors and laser-Doppler flowmetry, respectively, and quantify spinal cord metabolites with microdialysis. We demonstrate that high-thoracic SCI acutely impairs cardiac contractility and substantially reduces SCO2 and SCBF within the first hours post-injury. Utilizing the same model, we next show that augmenting LV contractility with the ß-agonist dobutamine increases SCO2 and SCBF more effectively than vasopressor therapy, whilst also mitigating increased anaerobic metabolism and hemorrhage in the injured cord. Finally, in pigs with T2 SCI survived for 12 weeks post-injury, we confirm that acute hemodynamic management with dobutamine appears to preserve cardiac function and improve hemodynamic outcomes in the chronic setting. Our data support that cardio-centric hemodynamic management represents an advantageous alternative to the current clinical standard of vasopressor therapy for acute traumatic SCI.


Assuntos
Coração/fisiopatologia , Hemodinâmica/fisiologia , Hemorragia/fisiopatologia , Fenômenos Fisiológicos Respiratórios , Traumatismos da Medula Espinal/fisiopatologia , Medula Espinal/fisiopatologia , Animais , Modelos Animais de Doenças , Dobutamina/farmacologia , Feminino , Fluxometria por Laser-Doppler , Chaperonas Moleculares/metabolismo , Norepinefrina/farmacologia , Fluxo Sanguíneo Regional/fisiologia , Traumatismos da Medula Espinal/tratamento farmacológico , Traumatismos da Medula Espinal/patologia , Suínos , Disfunção Ventricular Esquerda/tratamento farmacológico , Disfunção Ventricular Esquerda/fisiopatologia
4.
J Sports Med Phys Fitness ; 60(8): 1159-1166, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32955842

RESUMO

BACKGROUND: Endothelial function assessment may provide important insights into the cardiovascular function and long-term effects of exercise training. Many studies have investigated the possible negative effects on cardiovascular function due to extreme athletic performance, leading to undesirable effects. The purposes of this study were to investigate the acute effects of maximal intensity exercise on endothelium-dependent vasodilation, and to understand the patterns of flow-mediated dilation (FMD) change following maximal exercise in elite female athletes with a high-volume training history. METHODS: Twenty-six elite female soccer players (mean age, 22±4 years; BMI, 21±2 kg/m2; VO2max, 41±4 mL/kg/min) were evaluated. Brachial artery FMD was determined using high-resolution ultrasound at rest, and after 15 and 60 min of maximal cardiopulmonary exercise (CPX) testing on a treadmill. Flow velocity was measured at baseline and during reactive hyperemia at the same periods. RESULTS: Rest FMD was 12.4±5.5%. Peak diameter in response to reactive hyperemia was augmented after 15 min of CPX (3.5±0.4 vs. 3.6±0.4 mm, P<0.05), returning to resting values after 60 min. However, %FMD did not change among time periods. There were two characteristic patterns of FMD response following CPX. Compared to FMD at rest, half of the subjects responded with an increased FMD following maximum exercise (10.5±6.1 vs. 17.8±7.5%, P<0.05). The other subjects demonstrated a reduced FMD response following maximum exercise (14.2±4.3 vs. 10.9±3.2%, P<0.01). CONCLUSIONS: These results indicate that elite female soccer players presented robust brachial artery FMD at rest, with a heterogeneous FMD response to acute exercise with a 50% FMD improvement rate.


Assuntos
Endotélio Vascular/fisiologia , Exercício Físico/fisiologia , Condicionamento Físico Humano/fisiologia , Futebol/fisiologia , Vasodilatação/fisiologia , Adulto , Velocidade do Fluxo Sanguíneo , Artéria Braquial/diagnóstico por imagem , Artéria Braquial/fisiologia , Teste de Esforço , Feminino , Humanos , Fluxo Sanguíneo Regional/fisiologia , Adulto Jovem
5.
J Vis Exp ; (161)2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32804163

RESUMO

Coronary arterial tone along with the opening or closing of the capillaries largely determine the blood flow to cardiomyocytes at constant perfusion pressure. However, it is difficult to monitor the dynamic changes of the coronary arterioles and the capillaries in the whole heart, primarily due to its motion and non-stop beating. Here we describe a method that enables monitoring of arterial perfusion rate, pressure and the diameter changes of the arterioles and capillaries in mouse right ventricular papillary muscles. The mouse septal artery is cannulated and perfused at a constant flow or pressure with the other dynamically measured. After perfusion with a fluorescently labeled lectin (e.g., Alexa Fluor-488 or -633 labeled Wheat-Germ Agglutinin, WGA), the arterioles and capillaries (and other vessels) in right ventricle papillary muscle and septum could be readily imaged. The vessel-diameter changes could then be measured in the presence or absence of heart contractions. When genetically encoded fluorescent proteins were expressed, specific features could be monitored. For examples, pericytes were visualized in mouse hearts that expressed NG2-DsRed. This method has provided a useful platform to study the physiological functions of capillary pericytes in heart. It is also suitable for studying the effect of reagents on the blood flow in heart by measuring the vascular/capillary diameter and the arterial luminal pressure simultaneously. This preparation, combined with a state-of-the-art optic imaging system, allows one to study the blood flow and its control at cellular and molecular level in the heart under near-physiological conditions.


Assuntos
Arteríolas/diagnóstico por imagem , Capilares/diagnóstico por imagem , Imageamento Tridimensional , Pericitos/fisiologia , Animais , Arteríolas/efeitos dos fármacos , Arteríolas/fisiologia , Capilares/efeitos dos fármacos , Capilares/fisiologia , Cateterismo , Corantes Fluorescentes/metabolismo , Hemodinâmica/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Perfusão , Pericitos/efeitos dos fármacos , Pinacidil/farmacologia , Pressão , Fluxo Sanguíneo Regional/efeitos dos fármacos , Fluxo Sanguíneo Regional/fisiologia , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Vasodilatação/fisiologia , Aglutininas do Germe de Trigo/metabolismo
6.
Am J Physiol Regul Integr Comp Physiol ; 319(3): R323-R328, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32783690

RESUMO

Black men have attenuated increases in forearm vascular conductance (FVC) and forearm blood flow (FBF) during moderate- and high-intensity rhythmic handgrip exercise compared with White men, but the underlying mechanisms are unclear. Here, we tested for the first time the hypothesis that functional sympatholysis (i.e., attenuation of sympathetic vasoconstriction in the exercising muscles) is impaired in Black men compared with White men. Thirteen White and 14 Black healthy young men were studied. FBF (duplex Doppler ultrasound) and mean arterial pressure (MAP; Finometer) were measured at rest and during rhythmic handgrip exercise at 30% maximal voluntary contraction. FVC was calculated as FBF/MAP. Sympathetic activation was induced via lower body negative pressure (LBNP) at -20 Torr for 2 min at rest and from the 3rd to the 5th min of handgrip. Sympathetic vasoconstriction was assessed as percent reductions in FVC during LBNP. The groups presented similar resting FVC, FBF, and MAP. During LBNP at rest, reductions in FVC were not different between White (-35 ± 10%) and Black men (-32 ± 14%, P = 0.616), indicating similar reflex-induced sympathetic vasoconstriction. During handgrip exercise, there were minimal reductions in FVC with LBNP in either group (White: -1 ± 7%; Black: +1 ± 8%; P = 0.523), indicating functional sympatholysis in both groups. Thus, contrary to our hypothesis, our findings indicate a preserved functional sympatholysis in healthy young Black men compared with White men, suggesting that this mechanism does not appear to contribute to reduced exercise hyperemia during moderate-intensity rhythmic handgrip in this population.


Assuntos
Exercício Físico/fisiologia , Força da Mão/fisiologia , Consumo de Oxigênio/fisiologia , Vasoconstrição/fisiologia , Adulto , Humanos , Masculino , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Sistema Nervoso Simpático/fisiopatologia
7.
PLoS One ; 15(7): e0235392, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32726315

RESUMO

Platelets upregulate the generation of thrombin and reinforce the fibrin clot which increases the incidence risk of venous thromboembolism (VTE). However, the role of platelets in the pathogenesis of venous cardiovascular diseases remains hard to quantify. An experimentally validated model of thrombin generation dynamics is formulated. The model predicts that a high platelet count increases the peak value of generated thrombin as well as the endogenous thrombin potential (ETP) as reported in experimental data. To investigate the effects of platelets density, shear rate, and wound size on the initiation of blood coagulation, we calibrate a previously developed model of venous thrombus formation and implement it in 3D using a novel cell-centered finite-volume solver. We conduct numerical simulations to reproduce in vitro experiments of blood coagulation in microfluidic capillaries. Then, we derive a reduced one-equation model of thrombin distribution from the previous model under simplifying hypotheses and we use it to determine the conditions of clotting initiation on the platelet count, the shear rate, and the plasma composition. The initiation of clotting also exhibits a threshold response to the size of the wounded region in good agreement with the reported experimental findings.


Assuntos
Coagulação Sanguínea/fisiologia , Plaquetas/fisiologia , Modelos Teóricos , Contagem de Plaquetas/métodos , Testes de Coagulação Sanguínea , Plaquetas/metabolismo , Fibrina/metabolismo , Humanos , Agregação Plaquetária/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Resistência ao Cisalhamento/fisiologia , Trombina/metabolismo , Tromboplastina/metabolismo , Trombose/metabolismo , Trombose/fisiopatologia , Veias/metabolismo , Veias/fisiologia
8.
PLoS One ; 15(6): e0234861, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603330

RESUMO

OBJECTIVE: To examine whether the cardiac, renal and uterine physiological hemodynamic changes during gestation are altered in rats with an early and prolonged exposure to a high fat diet (HFD). METHODS: Arterial pressure and cardiac, renal, uterine and radial arteries hemodynamic changes during gestation were examined in adult SD rats exposed to normal (13%) (n = 8) or high (60%) (n = 8) fat diets from weaning. Plethysmography, high-resolution high-frequency ultrasonography and clearance of an inulin analog were used to evaluate the arterial pressure and hemodynamic changes before and at days 7, 14 and 19 of gestation. RESULTS: Arterial pressure was higher (P<0.05) in rats with high than in those with normal (NFD) fat diet before pregnancy (123 ±3 and 110 ±3 mmHg, respectively) and only decreased at day 14 of gestation in rats with NFD (98±4 mmHg, P<0.05). A significant increment in stroke volume (42 ±10%) and cardiac output (51 ±12%) was found at day 19 of pregnancy in rats with NFD. The changes in stroke volume and cardiac output were similar in rats with NFD and HFD. When compared to the values obtained before pregnancy, a transitory elevation in renal blood flow was found at day 14 of pregnancy in both groups. However, glomerular filtration rate only increased (P<0.05) in rats with NFD at days 14 (20 ±7%) and 19 (27 ±8%) of gestation. The significant elevations of mean velocity, and velocity time integral throughout gestation in radial (127 ±26% and 111 ±23%, respectively) and uterine (91 ±16% and 111 ±25%, respectively) arteries of rats with NFD were not found in rats with an early and prolonged HFD. SUMMARY: This study reports novel findings showing that the early and prolonged exposure to a HFD leads to a significant impairment in the renal, uterine and radial arteries hemodynamic changes associated to gestation.


Assuntos
Artérias/fisiopatologia , Vasos Coronários/fisiopatologia , Dieta Hiperlipídica/efeitos adversos , Fenômenos Fisiológicos da Nutrição Animal , Animais , Artérias/diagnóstico por imagem , Pressão Sanguínea/fisiologia , Vasos Coronários/diagnóstico por imagem , Feminino , Taxa de Filtração Glomerular/fisiologia , Rim/irrigação sanguínea , Modelos Animais , Gravidez , Ratos , Fluxo Sanguíneo Regional/fisiologia , Volume Sistólico/fisiologia , Ultrassonografia , Útero/irrigação sanguínea , Útero/diagnóstico por imagem
9.
PLoS One ; 15(6): e0235377, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603351

RESUMO

The purpose of this study was to investigate whether a six-week, twice weekly resistance training (4 sets at 30% 1-RM until failure) with practical blood flow restriction (BFR) using 7cm wide cuffs with a twist lock placed below the patella is superior to training without BFR (NoBFR) concerning muscle mass and strength gains in calf muscles. A two-group (BFR n = 12, mean age 27.33 (7.0) years, training experience 7.3 (7.0) years; NoBFR n = 9, mean age 28.9 (7.4) years, training experience 7.1 (6.6) years) randomized matched pair design based on initial 1-RM was used to assess the effects on structural and functional adaptations in healthy males (Perometer calf volume [CV], gastrocnemius muscle thickness using ultrasound [MT], 7-maximal hopping test for leg stiffness [LS], 1-RM smith machine calf raise [1-RM], and visual analogue scale as a measure of pain intensity [VAS]). The mean number of repetitions completed per training session across the intervention period was higher in the NoBFR group compared to the BFR group (70 (16) vs. 52 (9), p = 0.002). VAS measured during the first session increased similarly in both groups from first to fourth set (p<0.001). No group effects or time×group interactions were found for CV, MT, LS, and 1-RM. However, there were significant time effects for MT (BFR +0.07 cm; NoBFR +0.04; p = 0.008), and 1-RM (BFR +40 kg; NoBFR +34 kg; p<0.001). LS and CV remained unchanged through training. VAS in both groups were similar, and BFR and NoBFR were equally effective for increasing 1-RM and MT in trained males. However, BFR was more time efficient, due to lesser repetition per training session.


Assuntos
Adaptação Fisiológica , Força Muscular/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Adulto , Humanos , Masculino , Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Adulto Jovem
10.
Radiol Med ; 125(9): 838-850, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32671554

RESUMO

4D Flow is an emerging MR technique enabling three-dimensional and cardiac phase-resolved flowmetry with ECG-gated phase-contrast MRI that increased the speed of data acquisitions, accuracy and robustness. The method is promoting researches in areas that have not been fully addressed before in the cardiovascular system, such as flowmetry of the bloodstream across the valves, within the heart chambers, complexed flow dynamics such as vortex, helical or retrograde. Wall shear stress and other potential biomarkers derived from 4D Flow are known to be related to vascular wall diseases such as atherosclerosis. In this review, fundamental concepts of 4D Flow technique and post-processing, benefits and limitations as well as its clinical applications are discussed, and the importance of quality control and validation of the method is emphasized. New ideas inspired by 4D Flow can help clinicians and MR scientists further understand the role of flow dynamics in health sciences, diseases and various aspects of cardiovascular physiology.


Assuntos
Circulação Coronária/fisiologia , Imagem Cinética por Ressonância Magnética/métodos , Velocidade do Fluxo Sanguíneo , Eletrocardiografia/métodos , Humanos , Hidrodinâmica , Imageamento Tridimensional/métodos , Angiografia por Ressonância Magnética/métodos , Imagem por Ressonância Magnética/métodos , Fluxo Sanguíneo Regional/fisiologia , Resistência ao Cisalhamento/fisiologia
11.
Artigo em Inglês | MEDLINE | ID: mdl-32708408

RESUMO

The current pool of data investigating the effects of a single resistance exercise session on endothelial function is divergent and inconclusive. Therefore, the purpose of the present study was to evaluate the effect of a single resistance exercise session on flow-mediated dilation (FMD) in trained individuals. Eleven healthy, young, recreationally resistance-trained individuals participated in the study. After determining the resistance exercise workload, the participants performed three sets of 10-12 repetition of leg press and leg extension exercises. By using ultrasound equipment, brachial artery FMD was assessed before (PRE) and 30 min after (POST) the resistance exercise protocol or resting (control) to evaluate endothelial function. A significant reduction in FMD response (PRE: 5.73% ± 1.21% vs. POST: 4.03% ± 1.94%, p < 0.01) after resistance exercise was observed, accompanied by a large effect size (d = 1.05). No significant difference was observed in FMD in the control condition (PRE: 5.82% ± 1.19% vs. POST: 5.66% ± 1.24%, p = 0.704). Additionally, no significant difference in baseline brachial artery diameter between resistance exercise (PRE: 3.30 ± 0.32 vs. POST: 3.40 ± 0.34 mm, p = 0.494) and resting (PRE: 3.64 ± 0.41 vs. POST: 3.67 ± 0.62 mm, p = 0.825) was observed. Our findings showed that a single resistance exercise session induced a reduction in FMD in resistance-trained individuals.


Assuntos
Artéria Braquial/diagnóstico por imagem , Artéria Braquial/fisiologia , Endotélio Vascular/fisiologia , Exercício Físico/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Treinamento de Resistência , Vasodilatação/fisiologia , Adulto , Dilatação , Endotélio Vascular/diagnóstico por imagem , Feminino , Voluntários Saudáveis , Humanos , Masculino , Ultrassonografia , Adulto Jovem
12.
Am J Ophthalmol ; 218: 17-27, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32413411

RESUMO

PURPOSE: To perform a quantitative analysis of choriocapillaris (CC) flow deficits (FDs) in patients with uveitis. DESIGN: Retrospective cross-sectional study. METHODS: Swept-source optical coherence tomography based angiography (SS-OCTA) macular volume scans (3 × 3 mm and 6 × 6 mm) were obtained using the Plex Elite 9000. En face CC images were generated and analyzed using an automated FD identification algorithm. Three quantitative metrics were determined for each eye: FD number (FDN), mean FD size (MFDS), and FD density (FDD). Quantitative metrics were compared between uveitis and control eyes. The uveitis cohort was further subdivided by the presence or absence of choroidal involvement, and quantitative metrics were compared between subgroups and normal control subjects. RESULTS: A total of 38 eyes from 38 control subjects and 73 eyes from 73 uveitis subjects were included in this study. Eyes with uveitis have significantly larger CC MFDS (3- × 3-mm scans; P < .0001; 6- × 6-mm scans; P < .0001) and higher FDD (P = .0002; P = .0076, respectively) compared to control eyes. Additional analysis determined that these differences were due to the choroidal disease subgroup, which demonstrates significantly larger MFDS (3 × 3 = 1,108 µm2; 6 × 6 = 1,104 µm2) compared to both normal control eyes (752 µm2; P < .0001; 802 µm2; P < .0001, respectively) and uveitis patients without choroidal involvement (785 µm2; P < .0001; 821 µm2; P < .0001, respectively). No significant differences were found between the quantitative metrics of control subjects and patients without choroidal involvement. CONCLUSIONS: Automated quantification of CC can identify pathological FDs and provide quantitative metrics describing such lesions in patients with uveitis. Posterior uveitis patients have significantly larger CC FDs than patients with other forms of uveitis.


Assuntos
Corioide/irrigação sanguínea , Artérias Ciliares/fisiopatologia , Uveíte/fisiopatologia , Adulto , Idoso , Velocidade do Fluxo Sanguíneo/fisiologia , Estudos Transversais , Feminino , Angiofluoresceinografia , Humanos , Masculino , Pessoa de Meia-Idade , Fluxo Sanguíneo Regional/fisiologia , Estudos Retrospectivos , Tomografia de Coerência Óptica , Uveíte/diagnóstico , Adulto Jovem
13.
Invest Ophthalmol Vis Sci ; 61(5): 27, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32421146

RESUMO

Purpose: To determine whether the blood flow in the superior retina is significantly different from that in the inferior retina, and to determine whether the posture affects the blood flow in the superior and inferior retina. Methods: The blood flow in the vessels around the optic nerve head was measured by laser speckle flowgraphy in the sitting position in 68 healthy subjects. The blood flow in the superior peripapillary retina was compared with that in the inferior peripapillary retina. The measurements of the blood flow were performed in the sitting position, and the effect of switching to a supine position was determined at 2, 4, 6, 8, 10, and 30 minutes after the switch. Results: The total relative flow volume (RFV)-all, RFV-artery, and RFV-vein were significantly greater in the superior retina than in the inferior retina (all P < 0.001). The mean diameter-all and mean diameter-artery in the superior retina were significantly larger than that in the inferior retina (all P < 0.05). The mean blur rate (MBR)-all, MBR-artery, and MBR-vein in the superior retina were also greater than that in the inferior retina (P < 0.001, P < 0.01, and P < 0.001, respectively). Although the ocular perfusion pressure was significantly changed with the postural alteration, the total RFV-all remained greater in the superior retina than in the inferior retina after the postural change. Conclusions: Clinicians need to be aware of the differences in the blood flow between the superior and inferior retinal peripapillary area when considering the mechanisms of retinochoroidal diseases.


Assuntos
Fluxo Sanguíneo Regional/fisiologia , Retina/fisiologia , Vasos Retinianos/fisiologia , Adulto , Feminino , Hemodinâmica , Humanos , Fluxometria por Laser-Doppler , Masculino , Microcirculação , Oftalmoscopia , Disco Óptico/irrigação sanguínea , Postura/fisiologia , Microscopia com Lâmpada de Fenda , Acuidade Visual/fisiologia , Adulto Jovem
14.
Am J Physiol Renal Physiol ; 319(1): F33-F40, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32421350

RESUMO

Vascular dysfunction plays an important role in the etiology of chronic kidney disease (CKD) and is associated with cardiovascular diseases. Sex differences in vascular function are common in clinical and nonclinical populations. However, no data exist in individuals with CKD. The present study tested the hypothesis that sex and/or aging differences exist in vascular function in patients with CKD. Endothelium-dependent dilation (EDD; measured via brachial artery flow-mediated dilation) and endothelium-independent dilation (EID; measured via nitroglycerin-mediated dilation) were assessed. Analyses were adjusted for several variables that could influence vascular function (diabetes, cardiovascular disease, and blood pressure). Women, in general, had higher EDD values than men (6.5 ± 4.9% vs. 4.4 ± 3.4%); however, EID did not differ among these groups. In younger men and women (<55 yr old), EDD and EID were higher (P < 0.05) than their older (≥55 yr old) counterparts (EDD: 7.0 ± 4.1% vs. 4.4 ± 3.8% and EID: 24.0 ± 9.6% vs. 18.3 ± 9.2%). Additionally, younger women exhibited higher (P < 0.05) EDD and EID compared with younger men (EDD: 9.5 ± 6.4% vs. 5.1 ± 3.8%, P = 0.01, and EID: 24.0 ± 9.6% vs. 18.3 ± 9.2%). No differences in EDD and EID were present between older men and women with CKD. Diabetes independently predicted lower EID but not EDD in men and women. Blood pressure and cardiovascular disease did not predict EDD or EID. This is the first study to show significant sex differences in vascular function. Moreover, these differences are evident between younger men and women with CKD but are abolished with age. Additional studies are needed to better understand the mechanisms that may underlie sex differences in vascular dysfunction with CKD.


Assuntos
Artéria Braquial/fisiopatologia , Endotélio Vascular/fisiopatologia , Fluxo Sanguíneo Regional/fisiologia , Insuficiência Renal Crônica/fisiopatologia , Vasodilatação/fisiologia , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores Sexuais
15.
Am J Physiol Regul Integr Comp Physiol ; 319(1): R19-R25, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32401629

RESUMO

Microvascular endothelial dysfunction, a precursor to atherosclerotic cardiovascular disease, increases with aging. Endothelium-derived hyperpolarizing factors (EDHFs), which act through K+ channels, regulate blood flow and are important to vascular health. It is unclear how EDHFs change with healthy aging. To evaluate microvascular endothelial reliance on K+ channel-mediated dilation as a function of age in healthy humans. Microvascular function was assessed using intradermal microdialysis in healthy younger (Y; n = 7; 3 M/4 W; 26 ± 1 yr) and older adults (O; n = 12; 5 M/7 W; 64 ± 2 yr) matched for V̇o2peak (Y: 39.0 ± 3.8, O: 37.6 ± 3.1 mL·kg-1·min-1). Participants underwent graded local infusions of: the K+ channel activator Na2S (10-6 to 10-1 M), acetylcholine (ACh, 10-10 to 10-1 M), ACh + the K+ channel inhibitor tetraethylammonium (TEA; 25 or 50 mM), and ACh + the nitric oxide synthase-inhibitor l-NAME (15 mM). Red blood cell flux was measured with laser-Doppler flowmetry and used to calculate cutaneous vascular conductance (CVC; flux/mean arterial pressure) as a percentage of each site-specific maximum (%CVCmax, 43°C+28 mM sodium nitroprusside). The %CVCmax response to Na2S was higher in older adults (mean, O: 51.7 ± 3.9% vs. Y: 36.1 ± 5.3%; P = 0.03). %CVCmax was lower in the ACh+TEA vs. the ACh site starting at 10-5 M (ACh: 34.0 ± 5.7% vs. ACh+TEA: 19.4 ± 4.5%; P = 0.002) in older and at 10-4 M (ACh: 54.5 ± 9.4% vs. ACh+TEA: 31.2 ± 6.7%; P = 0.0002) in younger adults. %CVCmax was lower in the ACh+l-NAME vs. the ACh site in both groups starting at 10-4 M ACh (Y: P < 0.001; O: P = 0.02). Healthy active older adults have enhanced K+ channel-dependent endothelial vasodilatory mechanisms, suggesting increased responsiveness to EDHFs with age.


Assuntos
Endotélio Vascular/fisiologia , Envelhecimento Saudável/fisiologia , Canais de Potássio/fisiologia , Vasodilatação/fisiologia , Adulto , Idoso , Envelhecimento/fisiologia , Limiar Anaeróbio/fisiologia , Fatores Biológicos/fisiologia , Inibidores Enzimáticos/farmacologia , Eritrócitos/efeitos dos fármacos , Eritrócitos/fisiologia , Feminino , Humanos , Masculino , Microcirculação , Pessoa de Meia-Idade , NG-Nitroarginina Metil Éster/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/agonistas , Fluxo Sanguíneo Regional/fisiologia
17.
Radiol Med ; 125(12): 1288-1300, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32415476

RESUMO

Magnetic resonance imaging (MRI) is particularly attractive for clinical application in perfusion imaging thanks to the absence of ionizing radiation and limited volumes of contrast agent (CA) necessary. Dynamic contrast-enhanced MRI (DCE-MRI) involves sequentially acquiring T1-weighted images through an organ of interest during the passage of a bolus administration of CA. It is a particularly flexible approach to perfusion imaging as the signal intensity time course allows not only rapid qualitative assessment, but also quantitative measures of intrinsic perfusion and permeability parameters. We examine aspects of the T1-weighted image series acquisition, CA administration, post-processing that constitute a DCE-MRI study in clinical practice, before considering some heuristics that may aid in interpreting the resulting contrast enhancement time series. While qualitative DCE-MRI has a well-established role in the diagnostic assessment of a range of tumours, and a central role in MR mammography, clinical use of quantitative DCE-MRI remains limited outside of clinical trials. The recent publication of proposals for standardized acquisition and analysis protocols for DCE-MRI by the Quantitative Imaging Biomarker Alliance may be an opportunity to consolidate and advance clinical practice.


Assuntos
Meios de Contraste/farmacocinética , Aumento da Imagem/métodos , Imagem por Ressonância Magnética/métodos , Neoplasias/diagnóstico por imagem , Permeabilidade Capilar/fisiologia , Meios de Contraste/administração & dosagem , Espaço Extracelular/diagnóstico por imagem , Espaço Extracelular/metabolismo , Humanos , Neoplasias/irrigação sanguínea , Imagem de Perfusão/métodos , Fluxo Sanguíneo Regional/fisiologia
18.
Am J Ophthalmol ; 215: 25-36, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32224103

RESUMO

PURPOSE: This study was performed to investigate the association between changes in retinal layer thickness and perfusion status in the extramacular areas of eyes with diabetic retinopathy. DESIGN: Retrospective cross-sectional study. METHODS: The medical records of 70 eyes from 55 patients with diabetes were reviewed. The status of retinal perfusion in extramacular areas was evaluated using swept-source optical coherence tomography angiography. Retinal layer thickness was measured in nonperfused areas (NPA) larger than 2 optic disc areas, areas of sparse capillaries (SC), and perfused areas (PA-DR) in eyes with diabetic retinopathy. Retinal layer thickness was also measured in perfused areas in eyes without diabetic retinopathy (PA-NDR), and the thicknesses were then compared. In addition, swept-source optical coherence tomography angiography images and retinal thickness maps were compared to investigate the distribution of retinal thickness changes and spatial relationships to areas of retinal perfusion. RESULTS: The inner retinal thickness in NPA was significantly thinner than the inner retinal thicknesses in SC, PA-DR, and PA-NDR (all P < .001), and the inner retinal thickness in PA-NDR and SC was significantly thinner than that in PA-DR (P = .006 and .031, respectively). In a distribution analysis of the extramacular areas, NPA spatially overlapped with areas of severe retinal thinning in all locations. Local thickening with smooth shapes and gentle borders overlapped with areas of capillary abnormalities. Neovascularization was present at sites of local thickening with irregular shapes and unnatural clear borders. CONCLUSIONS: Changes in retinal layer thickness were associated with perfusion status, suggesting that retinal thickness maps can reflect perfusion status.


Assuntos
Retinopatia Diabética/fisiopatologia , Retina/patologia , Vasos Retinianos/fisiopatologia , Adulto , Idoso , Estudos Transversais , Retinopatia Diabética/diagnóstico por imagem , Feminino , Angiofluoresceinografia , Humanos , Masculino , Pessoa de Meia-Idade , Fibras Nervosas/patologia , Fluxo Sanguíneo Regional/fisiologia , Retina/diagnóstico por imagem , Células Ganglionares da Retina/patologia , Vasos Retinianos/diagnóstico por imagem , Estudos Retrospectivos , Tomografia de Coerência Óptica
19.
J Plast Reconstr Aesthet Surg ; 73(8): 1490-1498, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32241744

RESUMO

BACKGROUND: The macrovascular arteriovenous shunt (MAS) connecting the deep inferior epigastric artery (DIEA) and superficial inferior epigastric vein (SIEV) in the abdominal wall has already been identified as an important structure, and further study has been deemed necessary to establish its role and function. METHODS: Review of CT angiograms (CTA) of 38 female patients was undertaken, by means of analysis of fine-cut axial images and three-dimensional image reconstructions of the cutaneous vasculature of the deep and superficial vasculature. In vivo dissection of the structure was also performed to establish its communications. Lastly, a histopathological analysis was carried out to investigate its intrinsic structure and function. RESULTS: The MAS was identified in both sides of the abdomen in all subjects and the diameter ranges from 0.72 to 2.81 mm with a median diameter of 1.28 mm. In vivo dissection revealed it as a distinct structure connecting the DIEA and SIEV. Pathological analysis showed that it has characteristics of both elastic and muscular arteries, which constitutes a new vessel. CONCLUSION: These further investigations have yielded a better understanding of the MAS shunt, its position, structure and function. This can be of crucial importance to reconstructive surgeons when raising the DIEP flap.


Assuntos
Parede Abdominal/irrigação sanguínea , Angiografia por Tomografia Computadorizada , Artérias Epigástricas/anatomia & histologia , Retalho Perfurante/irrigação sanguínea , Veias/anatomia & histologia , Feminino , Humanos , Imageamento Tridimensional , Mamoplastia , Fluxo Sanguíneo Regional/fisiologia
20.
Am J Physiol Lung Cell Mol Physiol ; 318(6): L1211-L1221, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32294391

RESUMO

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is used as rescue therapy for severe cardiopulmonary failure. We tested whether the ratio of CO2 elimination at the lung and the V-A ECMO (V˙co2ECMO/V˙co2Lung) would reflect the ratio of respective blood flows and could be used to estimate changes in pulmonary blood flow (Q˙Lung), i.e., native cardiac output. Four healthy pigs were centrally cannulated for V-A ECMO. We measured blood flows with an ultrasonic flow probe. V˙co2ECMO and V˙co2Lung were calculated from sidestream capnographs under constant pulmonary ventilation during V-A ECMO weaning with changing sweep gas and/or V-A ECMO blood flow. If ventilation-to-perfusion ratio (V˙/Q˙) of V-A ECMO was not 1, the V˙co2ECMO was normalized to V˙/Q˙ = 1 (V˙co2ECMONorm). Changes in pulmonary blood flow were calculated using the relationship between changes in CO2 elimination and V-A ECMO blood flow (Q˙ECMO). Q˙ECMO correlated strongly with V˙co2ECMONorm (r2 0.95-0.99). Q˙Lung correlated well with V˙co2Lung (r2 0.65-0.89, P < = 0.002). Absolute Q˙Lung could not be calculated in a nonsteady state. Calculated pulmonary blood flow changes had a bias of 76 (-266 to 418) mL/min and correlated with measured Q˙Lung (r2 0.974-1.000, P = 0.1 to 0.006) for cumulative ECMO flow reductions. In conclusion, V˙co2 of the lung correlated strongly with pulmonary blood flow. Our model could predict pulmonary blood flow changes within clinically acceptable margins of error. The prediction is made possible with normalization to a V˙/Q˙ of 1 for ECMO. This approach depends on measurements readily available and may allow immediate assessment of the cardiac output response.


Assuntos
Oxigenação por Membrana Extracorpórea , Pulmão/irrigação sanguínea , Artéria Pulmonar/fisiologia , Troca Gasosa Pulmonar/fisiologia , Veias Pulmonares/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Animais , Modelos Animais de Doenças , Feminino , Masculino , Suínos
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