Determination Of Blood Flow Research Articles

Determinants of cerebral blood flow and arterial transit time in healthy older adults.

Cerebral blood flow (CBF) and arterial transit time (ATT), markers of brain vascular health, worsen with age. The primary aim of this cross-sectional study was to identify modifiable determinants of CBF and ATT in healthy older adults (n = 78, aged 60-81 years). Associations between cardiorespiratory fitness and CBF or ATT were of particular interest because the impact of cardiorespiratory fitness is not clear within existing literature. Secondly, this study assessed whether CBF or ATT relate to cognitive function in older adults. Multiple post-labelling delay pseudo-continuous arterial spin labelling estimated resting CBF and ATT in grey matter. Results from multiple linear regressions found higher BMI was associated with lower global CBF (β = -0.35, P = 0.008) and a longer global ATT (β = 0.30, P = 0.017), global ATT lengthened with increasing age (β = 0.43, P = 0.004), and higher cardiorespiratory fitness was associated with longer ATT in parietal (β = 0.44, P = 0.004) and occipital (β = 0.45, P = 0.003) regions. Global or regional CBF or ATT were not associated with processing speed, working memory, or attention. In conclusion, preventing excessive weight gain may help attenuate age-related declines in brain vascular health. ATT may be more sensitive to age-related decline than CBF, and therefore useful for early detection and management of cerebrovascular impairment. Finally, cardiorespiratory fitness appears to have little effect on CBF but may induce longer ATT in specific regions.

Study of some components of the influence and formation of blood flow in patients with "slow flow".

"Slow flow" is one very important concept in modern fundamental and clinical biomedicine. Slow coronary flow is indicative of delayed filling of the terminal coronary artery vessels, occurring in the absence of significant coronary stenosis. This group patient of patients exhibits a high incidence of disability and represents a significant financial and material burden for the state and the healthcare system in general. The primary objective of our study was to examine patients with slow coronary flow. We studied the standard parameters recommended by the international health care system (electrocardiography (by Medica QRS-12, Germany), through the electrical activity of a patient's heart by the electrical impulses (beating) of the heart; HC1(Germany); coagulogramma by Coatron M1 (Germany), troponin by AQT 90 (Germany); general blood test we used automatic human counting device HC1(Germany). Also, we investigate the original parameters (non-standard parameters, which we use in this pilot study) that we were first studied for this diagnosis and non-standard parameters. A general blood test showed that patients with slow flow had a higher blood leukocyte count than the control group, but the amount of hemoglobin was normal, the hematocrit was much higher than in the control group, and the platelet count was close to the lower limit of clinical standards.We obtained details of blood flow by coagulation situation, such as prothrombin time, prothrombin index, international normalized ratio, activated partial thromboplastin time, thrombin time, fibrinogen, and rheological properties such as index of erythrocyte aggregability, index of erythrocyte deformability, plasma viscosity, in silico blood rheological index. Blood flow can be considered as a superposition of vortices with similar frequencies and wave vectors that change after bifurcations or other obstacles in the vascular network. These factors together determine the conditions for structuring the flow of moving blood. Disruption or alteration of these factors results in slow flow. It has been found that the speed of blood flow in the coronary arteries depends on changes in the number and function of red blood cells. Slow flow is directly influenced by the aggregation and deformation of red blood cells, their number, and plasma viscosity. Consequently, the rheological status plays a crucial role in determining blood flow and its velocity.

Analysis of the Pulpal Blood Flow Microdynamics during Prosthetic Tooth Preparation Using Diamond Burs with Different Degrees of Wear.

Pulpal modifications taking place during prosthetic tooth preparation using worn-out burs may represent a risk for the vitality of the dental pulp. The aim of this in vivo study was to evaluate whether the wear of diamond burs has an influence on the vascular microdynamics at the level of the dental pulp, during vertical preparation for zirconia crowns. The study was performed with a split-mouth design and included 32 vital permanent monoradicular teeth (20 maxillary and 12 mandibular), from six subjects, aged between 20 and 50 years. The teeth were randomly assigned to two study groups of 16 teeth each. For prosthetic preparation, new burs were used in the first group, and burs at their 5th use were used in the second group. Four consecutive determinations of the pulpal blood flow by Laser Doppler flowmetry (LDF-laser Doppler MoorLab instrument VMS-LDF2, Moor Instruments Ltd., Axminster, UK) were taken for each tooth included in the study: before the preparation (control values), immediately, at 24 h, and at 7 days after the prosthetic preparation. A four-way ANOVA statistical analysis was applied to analyze the effect of four considered factors (bur wear degree, time of measurement, tooth number, and tooth location) on the pulpal blood flow (PBF). A significant increase in pulpal blood flow compared to the baseline was recorded immediately after preparation (p < 0.01), at 24 h (p < 0.01), and at 7 days (p < 0.05) in both groups, but more pronounced in the case of burs at the 5th use. The blood flow was significantly higher in upper jaw teeth, irrespective of the measurement time. In conclusion, the use of worn-out diamond burs produces lasting modifications in the pulpal blood flow of teeth that undergo prosthetic crown preparation. ISRCTN registry: ISRCTN49594720.

DOES EXERCISE CHANGE BLOOD FLOW TO TUMOURS? ACUTE AEROBIC EXERCISE EFFECTS ON LIVER METASTASES BLOOD FLOW: A CASE SERIES

AIM Effective cancer treatment relies on intravenous chemotherapy penetrating the entire tumour in sufficient concentrations, which is largely reliant on effective blood supply into and within the tumour. However, tumours contain abnormal vasculature with inefficient blood perfusion leading to the inability for chemotherapy to reach the target tumour. Pre-clinical evidence suggests acute exercise may increase blood flow by 200%. However, most pre-clinical studies investigate the effects of light-to-moderate intensity exercise and subsequently there is little evidence regarding the most effective exercise intensity for improved tumour vasculature. Therefore, the aim of this ongoing case series is to determine whether exercise changes tumour blood flow in a clinical model using non-invasive techniques, and how exercise intensity effects degree of change in blood flow to tumours in patients with liver metastases. METHODS Participants were eligible if they were aged over 18 years, had stage IV cancer with liver metastasis and ECOG 0-2. The study visit consisted of an aerobic fitness test (YMCA) to determine cardiorespiratory fitness and three 5-minute bouts of exercise at low, moderate and high intensities. After each exercise bout, Doppler ultrasound was used to measure a liver tumour vessel and the hepatic artery (as a control) to determine blood flow parameters. RESULTS Exercise increased peak systolic velocities (PSV) to liver tumours at all intensities compared to rest. Moderate and high exercise intensities showed a marked increase in PSV within the first 2 minutes after exercise. The hepatic artery showed less variability in PSV with time compared to the liver tumour. Cardiorespiratory fitness did not affect tumour PSV. CONCLUSION The results of this case series thus far suggest that exercise increases tumour blood flow at all exercise intensities with particular emphasis on moderate and high intensities. This supports the potential for using exercise as an adjunct to standard treatment to improve chemotherapy efficacy.

Effect of Dapagliflozin on Renal and Hepatic Glucose Kinetics in T2D and NGT Subjects.

Acute and chronic SGLT-2 inhibition increase endogenous glucose production (EGP). However, the organ - liver versus kidney - responsible for the increase in EGP has not been identified. 20 T2DM and 12 NGT subjects received [3-3H]-glucose infusion (to measure total EGP) in combination with arterial and renal vein catheterization and PAH infusion for determination of renal blood flow. Total EGP, net renal arteriovenous balance, and renal glucose production were measured before and 4 hours after dapagliflozin and placebo administration. Following DAPA, EGP increased in both T2D and NGT from baseline to 240 minutes, while there was a significant time-related decrease after placebo in T2D. Renal glucose production at baseline was <5% of basal EGP in both groups and did not change significantly following DAPA in either NGT and T2D. Renal glucose uptake (sum of tissue glucose uptake plus glucosuria) increased in both T2D and NGT following DAPA (P<0.05 vs placebo). The increase in RGU was entirely explained by the increase in glucosuria. Single dose of dapagliflozin significantly increased EGP, which primarily is explained by an increase in hepatic glucose production, establishing the existence of a novel renal-hepatic axis.

Prediction of long-term ischemic stroke with estimated whole blood viscosity in heart failure patients

Aims: Heart failure (HF) and stroke often coexist and share common risk factors, including atrial fibrillation. Whole blood viscosity (WBV), one of the most significant indicators of endothelial stress, is a fundamental determinant of blood flow and is involved in the aetiology of atherosclerosis and thrombosis. The purpose of this study was to assess the association between estimated WBV and long-term ischemic stroke (IS) risk in patients hospitalized for acute HF.&#x0D; Methods: A total of 409 patients with reduced ejection fraction HF hospitalized with acute HF were included. The primary outcome was IS post-discharge follow-up. &#x0D; Results: IS occurred in 26 (6%) patients during a follow-up. In the IS group, older age, diabetes mellitus frequency and WBV were higher, left ventricular end-diastolic and left atrial anteroposterior diameter were increased and left ventricular ejection fraction was lower. In multivariate regression analysis, WBV was found to be a predictor of long-term IS (OR, 2.68; 95% CI, 1.96-3.12, p=0.008). In the receiver operating characteristic curve, the optimal cut-off value of WBV for one-year IS was 6.28 with 61.5% sensitivity and 70.2% specificity (area under the curve: 0.748).&#x0D; Conclusion: WBV is a novel, easily measurable, cost-effective, non-invasive risk marker for the prediction of long-term IS in patients with HF, independent of traditional risk factors.

Current views on the functional role of hydrogen and its kinetics in the human body

The purpose of this overview was to present historical data on the discovery of hydrogen and a brief summary of its physical properties that form the basis for its use in aeronautics. Information is provided on the use of hydrogen, a biologically neutral molecule, in medicine as a diagnostic indicator for penetrating wounds of the gastrointestinal tract, the determination of local blood flow using the hydrogen clearance method, the use of the hydrogen breath test for the diagnosis of malabsorption and carbohydrate intolerance, achlorhydria, the diagnosis of bacterial overgrowth syndrome, the assessment of biodegradation of magnesium-containing implants, the orocecal transit time, and during deep-sea diving. The reasons for the sharp increase in the doctors’ interest in studying the biological role of hydrogen after the discovery of its antioxidant properties by a group of Japanese scientists (2007) are analyzed. In order to increase antioxidant protection of the body, data from recent research on ways to increase its concentration in the body through the supply of exogenous gas by inhalation or by administering hydrogen-rich water or saline solution is presented. Particular attention is paid to a critical analysis of studies on the kinetics of hydrogen by different routes, its concentration in blood and tissues, inhalation, and the use of hydrogen-rich water. Based on an analysis of publications, that the use of molecular hydrogen to relieve oxidative stress in the tissues of the intestines, liver and lungs is most promising, since its highest concentration is found in these tissues. Fermentation of carbohydrates has also been shown to increase the production of hydrogen by the intestinal microbiota. Considering that a large number of molecular hydrogen generators appeared on the market, the data on the requirements for their safety are summarized. Considerations on the use of molecular hydrogen for the purpose of antioxidant protection of the body in cardiology, gastroenterology, pulmonology, and other areas of medicine are based on modern views on the mechanisms of antioxidant, anti-apoptotic, cytoprotective, and anti-inflammatory effects of hydrogen. Particular attention is paid to the analysis of experimental and clinical research on the use of hydrogen in acute and chronic lung lesions, therapy of acute and chronic COVID-19 infection.Conclusion. Based on an analysis of the literature and our own data, a conclusion was drawn on the safety and prospects of the clinical use of molecular hydrogen in a wide range of concentrations in many diseases with the pathogenesis based on oxidative stress. In particular, the need for additional research was highlighted to clarify the regimen, frequency, duration and concentrations of hydrogen used, and a personalized approach to the combination of endogenous (from the intestinal microbiota) and exogenous hydrogen in various diseases.

Assessment of Collateral Pathways in Carotid Occlusion: Investigating the Clinical Significance of Ultrasound and TCCS

Background: Carotid occlusion is a severe condition closely associated with ischemic stroke. The prompt identification of patients presenting with extracranial carotid artery occlusion and the evaluation of collateral circulation compensation in these individuals bear significant clinical importance for subsequent patient management. Ultrasound offers significant advantages in the diagnosis of extracranial carotid artery stenosis and occlusion, while Transcranial Color-Coded Sonography (TCCS) is increasingly pivotal in assessing intracranial artery stenosis and determining blood flow direction. The objective of our study was to assess the concordance between ultrasound combined with TCCS and digital subtraction angiography (DSA) in evaluating extracranial carotid occlusion and intracranial collateral circulation.&#x0D; Methods: Patients with severe stenosis in the extracranial carotid artery were recruited for our study. All patients suspected of having occlusion in the extracranial carotid arteries underwent ultrasound, transcranial color-coded sonography (TCCS), and digital subtraction angiography (DSA). Sensitivity, specificity, positive predictive value, negative predictive value, overall accuracy, and kappa value were employed to assess the effectiveness and consistency of ultrasound and TCCS compared to DSA.&#x0D; Results: Ultrasound demonstrated a sensitivity of 85.4%, specificity of 100%, positive predictive value of 100%, negative predictive value of 90.4%, and overall accuracy of 93.9% in the diagnosis of extracranial artery occlusion. The kappa value was calculated as 0.87 (P＜0.001), indicating substantial agreement between ultrasound and DSA measurements for consistency assessment. Transcranial color-coded sonography (TCCS) exhibited a sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of 97.6%, 100%, 100%, 66.7%, and 97.7% respectively in evaluating collateral circulation in patients with carotid artery occlusion. The kappa value was 0.79 (P＜0.001) in assessing the collateral circulation in patients with occluded carotid arteries.&#x0D; Conclusions: Ultrasound proved to be a valuable tool for evaluating patients with occluded carotid arteries, while TCCS emerged as a reliable approach for assessing collateral pathways in individuals with extracranial carotid artery occlusion.

Enhanced external counterpulsation treatment regulates blood flow and wall shear stress metrics in femoral artery: An in vivo study in healthy subjects

As a non-invasive assisted circulation therapy, enhanced external counterpulsation (EECP) has demonstrated potential in treatment of lower-extremity arterial disease (LEAD). However, the underlying hemodynamic mechanism remains unclear. This study aimed to conduct the first prospective investigation of the EECP-induced responses of blood flow behavior and wall shear stress (WSS) metrics in the femoral artery. Twelve healthy male volunteers were enrolled. A Doppler ultrasound-basedapproach was introduced for the in vivo determination of blood flow in the common femoral artery (CFA) and superficial femoral artery (SFA) during EECP intervention, with incremental treatment pressures ranging from 10 to 40 kPa. Three-dimensional subject-specific numerical models were developed in 6 subjects to quantitatively assess variations in WSS-derived hemodynamic metrics in the femoral bifurcation. A mesh-independence analysis was performed. Our results indicated that, compared to the pre-EECP condition, both the antegrade and retrograde blood flow volumes in the CFA and SFA were significantly augmented during EECP intervention, while the heart rate remained constant. The time average shear stress (TAWSS) over the entire femoral bifurcation increased by 32.41%, 121.30%, 178.24%, and 214.81% during EECP with treatment pressures of 10 kPa, 20 kPa, 30 kPa, and 40 kPa, respectively. The mean relative resident time (RRT) decreased by 24.53%, 61.01%, 69.81%, and 77.99%, respectively. The percentage of area with low TAWSS in the femoral artery dropped to nearly zero during EECP with a treatment pressure greater than or equal to 30 kPa. We suggest that EECP is an effective and non-invasive approach for regulating blood flow and WSS in lower extremity arteries.

Myocardial Blood Flow Determination From Contrast-Free Magnetic Resonance Imaging Quantification of Coronary Sinus Flow.

Determination of myocardial blood flow (MBF) with MRI is usually performed with dynamic contrast enhanced imaging (MBFDCE ). MBF can also be determined from coronary sinus blood flow (MBFCS ), which has the advantage of being a noncontrast technique. However, comparative studies of MBFDCE and MBFCS in large cohorts are lacking. To compare MBFCS and MBFDCE in a large cohort. Prospective, sequence-comparison study. 147 patients with type 2 diabetes mellitus (age: 56+/-12 years; 106 male; diabetes duration: 12.9+/-8.1 years), and 25 age-matched controls. 1.5 Tesla scanner. Saturation recovery sequence for MBFDCE vs. phase-contrast gradient-echo pulse sequence (free-breathing) for MBFCS . MBFDCE and MBFCS were determined at rest and during coronary dilatation achieved by administration of adenosine at 140 μg/kg/min. Myocardial perfusion reserve (MPR) was calculated as the stress/rest ratio of MBF values. Coronary sinus flow was determined twice in the same imaging session for repeatability assessment. Agreement between MBFDCE and MBFCS was assessed with Bland and Altman's technique. Repeatability was determined from single-rater random intraclass and repeatability coefficients. Rest and stress flows, including both MBFDCE and MBFCS values, ranged from 33 to 146 mL/min/100 g and 92 to 501 mL/min/100 g, respectively. Intraclass and repeatability coefficients for MBFCS were 0.95 (CI 0.90; 0.95) and 5 mL/min/100 g. In Bland-Altman analysis, mean bias at rest was -1.1 mL/min/100 g (CI -3.1; 0.9) with limits of agreement of -27 and 24.8 mL/min/100 g. Mean bias at stress was 6.3 mL/min/100 g (CI -1.1; 14.1) with limits of agreement of -86.9 and 99.9. Mean bias of MPR was 0.11 (CI: -0.02; 0.23) with limits of agreement of -1.43 and 1.64. MBF may be determined from coronary sinus blood flow, with acceptable bias, but relatively large limits of agreement, against the reference of MBFDCE . 1 TECHNICAL EFFICACY STAGE: 2.

Comparison of phase contrast magnetic resonance imaging and scintigraphy for determination of split pulmonary blood flow in children and young adults with congenital heart disease.

Measurement of differential blood flow to the lungs is important to understanding flow dynamics in the setting of congenital heart disease. Split blood flow via the pulmonary arteries guides and demonstrates the effect of interventions. Minimally invasive imaging of pulmonary blood flow can be achieved with scintigraphy or magnetic resonance imaging (MRI). To assess agreement of pulmonary blood flow measurements obtained by scintigraphy and MRI in children and young adults. We performed a retrospective review of patients < 21years of age who had undergone both nuclear medicine pulmonary perfusion scans (Tc-99m MAA) and cardiac MRI examinations from January 2012 to August 2021 at our tertiary pediatric hospital. Patient demographics, medical/surgical information, and estimates of split blood flow by both modalities were recorded. Pearson's correlation coefficient was used to determine the relationship between split blood flow measured by the two examinations. Agreement was calculated using interclass correlation coefficient (ICC) for absolute agreement and Bland-Altman difference analysis. Correlation between split blood flow measured by scintigraphy and MRI using net flow was 0.90 (95% CI: 0.83-0.94, P< 0.001) and the ICC for agreement on split blood flow was 0.90 (95% CI: 0.84-0.94). Mean difference in split blood flow by Bland-Altman analysis was 0.79% with 95% limits of agreement (-11.2 to 12.8%). There is excellent agreement between Tc-99m scintigraphy and phase contrast MRI for quantification of split pulmonary blood flow in children and young adults with congenital heart disease.

Evaluation of the validity of mental foramen USG measurements by comparison with CBCT and determination of blood flow.

To examine mental foramen (MF) morphology and morphometry in comparison with ultrasonography (USG) and cone-beam computed tomography (CBCT), and to determine the relationship between mental artery blood flow parameters and age, gender, dental status, alveolar crest height, mandibular cortical index (MCI) with USG. A total of 120 MF and mental arteries of 60 patients (21 males and 39 females), including 20 patients in each group, aged 18-39, 40-59, and 60years and above, were evaluated. The horizontal and vertical diameter of the MF and the distance between it and the alveolar crest were evaluated with USG and CBCT. In addition, mental artery blood flow parameters were examined by USG. When the horizontal diameter values of MF were compared in USG and CBCT measurements; the diameter was significantly lower in the measurements obtained by USG (p < 0.05). It was observed that there were no mental arteries whose blood flow could not be recorded, 31 (25.8%) had strong blood flow and 89 (74.2%) had weak blood flow. No significant correlation was observed between gender and blood flow parameters (p > 0.05). Considering that CBCT images are used as gold standard in our study, it may be said that USG is not as reliable as CBCT in evaluating the MF dimensions in the maxillofacial region. Nevertheless, USG is a suitable technique for determining the visualizing and blood flow of the MF.

Кардиальная дисфункция у плода: влияние на исходы в перинатальном периоде у недоношенных детей

Objective. To study the importance of fetal cardiac dysfunction in the genesis of perinatal brain damage in premature newborns. Patients and methods. A prospective cohort comparative study included 59 preterm infants with gestational age from 26 to 32 weeks and body weight from 590 to 1990. Newborns were divided into 2 groups at the 1st month of life: the main group (n = 38), which included children with structural brain lesions, and the control group (n = 21) with favorable neurological outcomes. There were no statistically significant differences in either body weight or gestational age between the groups. At the antenatal stage, all underwent ultrasound doppler sonography of uteroplacental blood flow, and the cerebral-placental ratio was calculated. The following markers were determined at the 1st day of postnatal life: levels of lactate, cerebral natriuretic propeptide and soluble type 2 tumor suppressor in the umbilical cord blood of a newborn (enzyme-linked immunosorbent assay); neurosonography of the brain with the determination of blood flow and doppler echocardiography. Neurological outcomes were assessed after 1 month of life after the control neurosonography of brain. The data are presented in the form of median, maximum and minimum values – Me [min; max]. The obtained data were processed using the Statistica 6.1 program. The Mann–Whitney and Fisher χ2 criteria with the Yeats correction were calculated. The differences were considered significant at p equal to 0.05. Results. The pulsation index in the umbilical cord artery was significantly higher (1.270 [1.120; 1.320] versus 0.984 [0.798; 1.120]) in the fetuses of the main group, Its values indicating severe disorders of fetal-placental hemodynamics were more often recorded (in 15–39.5% cases versus 4–19.1%). The significant decrease in the cerebroplacental ratio was significantly more often recorded (in 18–47.4% cases versus 2–9.5%) in the same group. The levels of lactate (3.6 [2.1; 5.2] versus 2.25 [1.3; 3.05] mmol/L) and cerebral natriuretic propeptide (243.2 [84.17; 1385] versus 111.6 [64.8; 2903] pg/ml, respectively) were significantly elevated in the umbilical cord blood, in newborns of the main group. The newborns of the main group had significantly lower levels of systolic, diastolic and mean blood pressure, at the first hours of life. They also had a reduced level of blood flow in the superior vena cava (Me = 65 ml/kg/min; 9 (23.7%) children had a periventricular leukomalacia, 18 (47.4%) – intraventricular hemorrhages of the II–III degree, and 2 (5.3%) had a stroke. Conclusion. It is very important to pay attention of pediatricians-neonatologists to the antenatal period. Treating the fetus as a patient, early assessment of hemodynamics and timely diagnosis of fetal cardiac dysfunction and other developmental abnormalities will reduce the incidence of disabling perinatal diseases and the level of perinatal mortality. Key words: antenatal diagnosis, umbilical cord blood lactate, prematurity, perinatal brain damage, placental insufficiency, fetal cardiac dysfunction

Modeling and computation for unsteady blood flow and solute concentration in a constricted porous artery

&lt;abstract&gt; &lt;p&gt;We investigated a physical system for unsteady blood flow and solute transport in a section of a constricted porous artery. The aim of this study was to determine effects of hematocrit, stenosis, pulse oscillation, diffusion, convection and chemical reaction on the solute transport. The significance of this study was uncovering combined roles played by stenosis height, hematocrit, pulse oscillation period, reactive rate, blood speed, blood pressure force and radial and axial extent of the porous artery on the solute transported by the blood flow in the described porous artery. We used both analytical and computational methods to determine blood flow quantities and solute transport for different parametric values of the described physical system. We found that solute transport increases with increasing stenosis height, blood pulsation period, convection and blood pressure force. However, transportation of solute reduces with increasing hematocrit, chemical reactive rate and radial or axial distance.&lt;/p&gt; &lt;/abstract&gt;

Reliability of rubidium-82 PET/CT for renal perfusion determination in healthy subjects

BackgroundChanges in renal perfusion may play a pathophysiological role in hypertension and kidney disease, however to date, no method for renal blood flow (RBF) determination in humans has been implemented in clinical practice. In a previous study, we demonstrated that estimation of renal perfusion based on a single positron emission tomography/computed tomography (PET/CT) scan with Rubidium-82 (82Rb) is feasible and found an approximate 5% intra-assay coefficient of variation for both kidneys, indicative of a precise method.This study’s aim was to determine the day-to day variation of 82Rb PET/CT and to test the method’s ability to detect increased RBF induced by infusion of amino acids.MethodsSeventeen healthy subjects underwent three dynamic 82Rb PET/CT scans over two examination days comprising: Day A, a single 8-minute dynamic scan and Day B, two scans performed before (baseline) and after RBF stimulation by a 2-hour amino acid-infusion. The order of examination days was determined by randomization. Time activity curves for arterial and renal activity with a 1-tissue compartment model were used for flow estimation; the K1 kinetic parameter representing renal 82Rb clearance. Day-to-day variation was calculated based on the difference between the unstimulated K1 values on Day A and Day B and paired t-testing was performed to compare K1 values at baseline and after RBF stimulation on Day B.ResultsDay-to-day variation was observed to be 5.5% for the right kidney and 6.0% for the left kidney (n = 15 quality accepted scans). K1 values determined after amino acid-infusion were significantly higher than pre-infusion values (n = 17, p = 0.001). The mean percentage change in K1 from baseline was 13.2 ± 12.9% (range − 10.4 to 35.5) for the right kidney; 12.9 ± 13.2% (range − 15.7 to 35.3) for the left kidney.ConclusionDay-to-day variation is acceptably low. A significant K1 increase from baseline is detected after application of a known RBF stimulus, indicating that 82Rb PET/CT scanning can provide a precise method for evaluation of RBF and it is able to determine changes herein.Clinical Trial RegistrationEU Clinical Trials Register, 2017-005008-88. Registered 18/01/2018.

Abstract 15081: The Viscoelastic Yield Stress of Blood is Negatively Associated With Pulmonary Blood Flow in the Fontan Circulation

Introduction: In the Fontan (FN) circulation pulmonary blood flow (Qp) is passive, resulting in severely decreased shear rate and velocity in pulmonary arteries to the point of stasis. Yield stress (YS) is the shear stress required for blood to transition from stasis to a moving fluid. Therefore, YS may be a determinant of Qp in FN. We evaluated YS in patients with FN and Glenn (GLN) circulations and whether increased YS is associated with decreased Qp. Methods: We enrolled 20 patients with biventricular (2V) congenital heart disease (CHD) and 41 patients with single ventricle CHD (19 FN and 22 GLN) who were undergoing a clinically indicated cardiac catheterization. Two patients were excluded due to pulmonary vascular disease. We obtained blood samples at the time of catheterization and measured blood viscosity across shear rates 1 s -1 to 1000 s -1 using a Rheolog viscometer We calculated YS by curve-fitting of the viscosity measurements to a Casson fluid model. Hypothesis: We hypothesize that higher yield stress will be associated with lower pulmonary blood flow in Fontan circulation. Results: The FN group was the oldest and had the largest BSA (FN&gt;2V&gt;GLN; p&lt;0.0001). Hematocrit was highest in GLN (GLN&gt;FN&gt;2V; p&lt;). Blood viscosity was higher across all shear rates in GLN compared to both FN and 2V (p&lt;0.001 for all shear rates) and higher in FN than 2V from 1 s -1 to 150 s -1 (p&lt;0.05 for all shear rates). YS was highest in GLN (GLN&gt;FN&gt;2V; p&lt; ). YS was negatively associated with Qp in both FN (R2 0.33, p=0.02) and GLN (R2 0.2, p=0.038), but not 2V (see Figure). Hematocrit was negatively associated with Qp in 2V (R2 0.34, p=0.028) and trended toward negative association in FN (R2 0.27, p=0.099), but not in GLN. Stepwise regression of Hct and YS vs Qp in FN demonstrated YS as the primary predictor of Qp. Conclusions: Our data demonstrate that the yield stress of blood derived from the Casson fluid model is a significant determinant of pulmonary blood flow in FN circulation.

Differences In Blood-flow Patterns Of The Carotid Artery Between Two Exercise Modalities At Three Intensities

Endothelial shear stress (ESS), frictional force produced by red blood cells on endothelial cells, helps to maintain endothelial homeostasis, and help to determine blood flow patterns. Purpose: This study seeks to determine exercise-induced blood flow patterns in the carotid artery during different exercise modalities (back squat and treadmill running) at 3 different intensities. Methods: Fourteen participants (7 males and 7 females) participated in a repeated measures study design. Three sessions were performed to obtain baseline measurements, 1-repetition maximum back squat test (1RM Squat), and treadmill maximum oxygen uptake test (VO2max). Two more sessions, for squat and treadmill, were randomized within a week after the baseline measurements. Squat intensities selected: low = 45% 1RM, moderate = 65% 1RM, and high = 85% 1RM. Running intensities were selected using blood lactate levels: low = 0-2 mmol/L, moderate = 2-4 mmol/L, and high >4.0 mmol/L from the VO2max test. Blood flow patterns of the carotid artery (diameter and blood flow velocity) and presence of turbulence determined by calculation of Reynolds number (Re), were obtained using ultrasound imaging and Doppler. Data analysis used a 2-way repeated-measures ANOVA, with Holm-Bonferroni post-hoc analysis to determine pairwise differences between modalities and intensity. Statistical significance was set at α = 0.05. Results: There were main effects and interaction between intensity and exercise modalities (p < 0.05) for ESS. Pairwise comparisons showed difference in moderate (p < 0.05) and high (p < 0.05) intensity in both modalities (Figure 1A) compared to low intensity. Similarly, there was a main effect of exercise intensity (p < 0.05) for Re. Pairwise comparisons indicate significant difference (p < 0.05) in high intensity in both modalities (Figure 1B) compared to low intensity. Conclusion: Results indicated turbulent blood flow patterns across all intensities and modalities; however, high intensity treadmill yields greater turbulent blood flow. Furthermore, ESS increases linearly as intensity increases, with greater magnitude in moderate and high intensity treadmill. Clinicians should be aware of differences in carotid artery hemodynamics at different exercise intensities and modes to prescribe better exercise interventions.

Ion channels and channelopathies in glomeruli.

An essential step in renal function entails the formation of an ultrafiltrate that is delivered to the renal tubules for subsequent processing. This process, known as glomerular filtration, is controlled by intrinsic regulatory systems and by paracrine, neuronal, and endocrine signals that converge onto glomerular cells. In addition, the characteristics of glomerular fluid flow, such as the glomerular filtration rate and the glomerular filtration fraction, play an important role in determining blood flow to the rest of the kidney. Consequently, disease processes that initially affect glomeruli are the most likely to lead to end-stage kidney failure. The cells that comprise the glomerular filter, especially podocytes and mesangial cells, express many different types of ion channels that regulate intrinsic aspects of cell function and cellular responses to the local environment, such as changes in glomerular capillary pressure. Dysregulation of glomerular ion channels, such as changes in TRPC6, can lead to devastating glomerular diseases, and a number of channels, including TRPC6, TRPC5, and various ionotropic receptors, are promising targets for drug development. This review discusses glomerular structure and glomerular disease processes. It also describes the types of plasma membrane ion channels that have been identified in glomerular cells, the physiological and pathophysiological contexts in which they operate, and the pathways by which they are regulated and dysregulated. The contributions of these channels to glomerular disease processes, such as focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy, as well as the development of drugs that target these channels are also discussed.

Konsep GHOST- CAP untuk Proteksi Otak Perioperatif pada Cedera Otak Traumatik

Brain damage is an injury that causes damage or worsening of brain cells caused by various conditions such as head trauma, inadequate oxygen supply, infection or intracranial hemorrhage. Brain protection is a preemptive measure of therapeutic interventions to improve neurological outcomes in patients at risk of cerebral ischemic, while brain resuscitation refers to therapeutic interventions that begin after the occurrence of ischemic. The target is ischemic therapy and reducing neuronal injury. Perioperative brain damage is one of the most serious adverse complications of surgery and anesthesia, resulting in new postoperative neurological deficits. The concept of GHOST-CAP, an acronym for Glycemia, Hemoglobin, Oxygen, Sodium, Temperature, Comfort, Arterial Pressure and PaCO2, can be used in the postoperative period. G: The target level of glucose is between 80 and 180 mg/dL. H: hemoglobin threshold is 7-9 g/dL. O: oxygen, target SpO2 between 94 and 97%. S: Sodium concentration affects brain volume, sodium levels up to 155 mEq/L are tolerable. T: temperatures regulated to optimize cellular function, but core temperatures &gt; 38.0°C should be avoided. C: patient comfort, including pain control, agitation, anxiety, and chills. A: Arterial blood pressure is the main determinant of cerebral blood flow (CBF), maintaining an mean arterial pressure (MAP) of 80 mmHg and cerebral perfusion pressure (CPP) of 60 mmHg. P: Acute changes in PaCO2 cause CBF changes, PaCO2 not to be less than 35 mmHg. This paper examines the GHOST-CAP concept for perioperative brain protection, whether adequate or should be supplemented

55-LB: Effect of Dapagliflozin on Renal and Hepatic Glucose Kinetics in T2DM and NGT Subjects

We previously have shown that both acute and chronic SGLT-2 inhibition increases endogenous glucose production (EGP) . However, the organ - liver versus kidney - responsible for the increase in EGP has not been identified. We assessed the effect of a single dose of Dapagliflozin or Placebo on renal glucose production in 13 T2DM (age=57.5±1.8 yrs, BMI = 30±1.4 kg/m2) and 9 NGT (age 42±2 3 yrs, BMI = 30±1.1 kg/m2) subjects. Renal glucose production was measured using arteriovenous balance technique across the kidney combined with [3-3H] glucose infusion and PAH infusion (for determination of renal blood flow) before and 4 hours after administration of Dapagliflozin (10 mg) and Placebo; thus, each subject served as their own control. EGP increased following DAPA in both T2DM (2.00±0.11 to 2.43±0.15, P&amp;lt;0.05) and NGT (1.72±0.11 to 2.1±0.16, p&amp;lt;0.05) , while it decreased after placebo in T2DM (2.02±0.12 vs. 1.15±0.06) and NGT (2.10±0.2 vs. 2.05±0.1) (both p&amp;lt;0.01, DAPA vs. placebo) . The fractional renal extraction of glucose (0.02± 0.004 vs. 2.99 ± 1.0, p=0.001 in T2DM, and 0.02± 0.004 vs. 1.62± 1.4 in NGT, p=NS) and renal glucose uptake (0.067 ± 0.02 vs. 0.347 ± 0.06 in T2DM and 0.08 ± 0.02 vs. 0.27 ± 0.08 mg/kg.min in NGT) were higher following DAPA vs. placebo (p&amp;lt;0.05) and were entirely explained by the increase in glucosuria. There was a small, non-significant increase (0.065 &amp; 0.032 mg/kg.min, respectively) in renal glucose production (RGP) following dapagliflozin in T2DM and NGT compared to the 0.45 mg/kg.min increase in total body EGP. Conclusion: A single dose of Dapagliflozin significantly increases EGP which primarily is explained by an increase in hepatic glucose production. Disclosure X. Chen: None. C. Solis-herrera: Speaker’s Bureau; Novo Nordisk. D. Tripathy: None. A. A. Hansis-diarte: None. R. Chilton: Advisory Panel; AstraZeneca, Boehringer Ingelheim International GmbH, Nova Biomedical. E. Cersosimo: Research Support; AstraZeneca. R. A. Defronzo: Advisory Panel; AstraZeneca, Boehringer Ingelheim International GmbH, Intarcia Therapeutics, Inc., Novo Nordisk, Research Support; AstraZeneca, Boehringer Ingelheim International GmbH, Merck &amp; Co., Inc., Speaker’s Bureau; AstraZeneca. Funding Astra Zeneca