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It is important to understand the dynamics of red blood cells (RBCs) in blood flow. This requires the formulation of coarse-grained RBC models that reproduce the hydrodynamic properties of blood accurately. One of the models that successfully reproduces the rheology and morphology of blood has been proposed by Fedosov et al. [Comput. Methods Appl. Mech. Eng. 199, 1937–1948 (2010)]. The proposed RBC model contains several parameters whose values are determined by either various experiments or physical requirements. In this study, we developed a new method of determining parameter values precisely from the fluctuations of the RBC membrane. Specifically, we studied the relationship between the spectra of the fluctuations and model parameters. Characteristic peaks were observed in the spectra, whose peak frequencies were dependent on the parameter values. In addition, we investigated the spectra of the radius of gyration. We identified the peaks originating from the spring potential and the volume-conserving potential appearing in the spectra. These results lead to the precise experimental determination of the parameters used in the RBC model. [ABSTRACT FROM AUTHOR]

In the present study, a Caputo–Fabrizio (C–F) time-fractional derivative is introduced to the governing equations to present the flow of blood and the transport of magnetic nanoparticles (MNPs) through an inclined porous artery with mild stenosis. The rheology of blood is defined by the non-Newtonian visco-elastic Jeffrey fluid. The transport of MNPs is used as a drug delivery application for cardiovascular disorder therapy. The momentum and transport equations are solved analytically by using the Laplace transform and the finite Hankel transform along with their inverses, and the solutions are presented in the form of Laplace convolutions. To display the solutions graphically, the Laplace convolutions are solved using the numerical integration technique. The study presents the impacts of different governing parameters on blood and MNP velocities, volumetric flow rate, flow resistance, and skin friction. The study demonstrates that blood and MNP velocities boost with an increase in the fractional order parameter, Darcy number, and Jeffrey fluid parameter. The volumetric flow rate decreases and flow resistance increases with enhancement in stenosis height. The non-symmetric shape of stenosis and the rheology of blood decrease skin friction, whereas enhancement in MNP concentration increases skin friction. A comparison of the present result with the previous work shows excellent agreement. The present study will be beneficial for the field of medical science to further study atherosclerosis therapy and other similar disorders. [ABSTRACT FROM AUTHOR]

Clinical Scenario: Stress fractures are one of the most common injuries in athletes. Unfortunately, they are hard to diagnose, require multiple radiology exams and follow-up which leads to more exposure to radiation and an increase in cost. Stress fractures that are mismanaged can lead to serious complications and poorer outcomes for the athlete. During the rehabilitation process, it would be beneficial to be able to monitor the healing of fractures to know when it is safe to gradually allow a patient to a return to sport because the return to activity is not usually objective and based on pain level. Clinical Question: Can infrared thermography (IRT) be a useful tool to measure the pathophysiological state of the fracture healing? The aim of this critically appraised topic is to analyze the current evidence of IRT for measuring the temperature change in fractures to provide recommendations for medical practitioners. Summary of Key Findings: For this critically appraised topic, we examined 3 articles that compared medical imaging and IRT over multiple time points during the follow-up. The 3 articles concluded that a 1 °C asymmetry in temperature followed by a return to normal (less than 0.3 °C) temperature during the healing process of fractures can be monitored using IRT. Clinical Bottom Line: Once the patient has been diagnosed with a fracture, IRT can safely be used to monitor the evolution of a fracture. When the thermogram progresses from a hot thermogram to a cold thermogram, the healing is considered good enough to return to sport. Strength of Recommendation: Grade 2 evidence exists to support IRT being used by clinicians to monitor fracture healing. Due to the limited research and novelty of the technology, the current recommendations are for following the treatment of the fracture once the initial diagnosis is made. [ABSTRACT FROM AUTHOR]

The objective of this research is to predict the thermal observations for hybrid nanofluid conveying the thin film flow influenced by the suction phenomenon and slip consequences. The copper and aluminum nanoparticles are utilized to explore the hybrid nanofluid features. In addition, a uniform magnetic field perpendicular to the motion of the nanoliquid has been generated. By utilizing appropriate dimensionless quantities, partial differential equations (PDEs) are transformed into nonlinear ordinary differential equations (ODEs). The controlling method for boundary value problems (BVP4C) has been applied against the thermal profile. The coating film's thickness has been kept fixed. The skin friction and Nusselt number distribution are calculated for blood over the shrinking sheet in the attendance of the radiation and velocity slip parameters. The effects of various variables and spray rate through coating are clearly represented. The numerical calculation is computed for assessing the wall shear force. It is observed that a dual branch has been discovered. In addition, a stability analysis has been conducted and the upper branch has been determined to be the stable branch. [ABSTRACT FROM AUTHOR]

BackgroundMethodsResultsConclusionTrial registrationA pallor optic nerve head (ONH) is one of the three features of retinitis pigmentosa (RP). This study aimed to assess the ONH prospectively by color tone, presence of hyper-reflective tissue, blood flow, retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) and investigate the change in these parameters with and without ONH pallor.The presence of ONH pallor was assessed by three independent examiners through careful examination using fundus photographs. The presence of a hyper-reflective structure on the ONH was carefully evaluated using a volume scan optical coherence tomography (OCT). RNFL thickness and ellipsoid zone (EZ) width around the macula were also evaluated by OCT. Laser speckle flowgraphy was used to measure the mean blur rate of the entire ONH area, which was subsequently divided into the vessel area (MV) and tissue area (MT).Twenty-eight eyes of 28 patients with RP (55.4 ± 16.23 years of age) were included. The pale ONH was observed in 10 (35%) eyes. Hyper-reflective structures were observed in seven (25%) eyes. No significant correlation was found between the pale ONH and the presence of a hyper-reflective structure (Pearson’s chi-squared test, p = .364). The average of the ONH area, MV, and MT was 8.65 ± 3.08 AU, 17.81 ± 7.54 AU, and 6.4 ± 2.66 AU, respectively, which significantly decreased in patients with pallor ONH (all p < .05). The global RNFL thickness was 73.54 ± 18.82 μm. The nasal and superior quadrants and global RNFL thickness in patients with a pale ONH were significantly thinner than in patients without a pale ONH (all p < .05). The global and superior and inferior GCC thickness in patients with a pale ONH were significantly thinner than in patients without a pale ONH(all p < .05).There was no difference in the EZ width between patients with and without a pale ONH (p = .107).We conducted multiple assessments of the ONH in RP patients and investigated its clinical significance. Our findings suggest that ONH pallor may indicate a comprehensive change that emerges alongside the progression of retinal degeneration in RP.This trial was retrospectively registered in the UMIN Clinical Trial Registry (UMIN ID: 000048168). [ABSTRACT FROM AUTHOR]

Aim: To assess the impact of endoscopic stone surgeries on renal perfusion and blood flow in children. Materials and methods: Children who underwent percutaneous nephrolithotomy (PCNL), retrograde intrarenal surgery (RIRS), ureterorenoscopy (URS), endoscopic combined intrarenal surgery (ECIRS) were included to the study. Renal Doppler ultrasonography (RDUS) was performed one day before the operation, and on the postoperative 1st day and 1st month. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) were measured, and resistive index (RI) was calculated with the (PSV-EDV)/PSV formula. RDUS parameters were compared before and after surgery and between ipsilateral and contralateral kidneys. Results: A total of 45 children with a median age was 8 (2–17) years were included (15 (33.3%) girls, 30 (66.7%) boys). PCNL was performed in 13 children (28.9%), RIRS 11 (24.4%), URS 12 (26.7%), and ECIRS 9 (20%). There was no significant difference in renal and segmental PSV, EDV and RI values of operated kidney in the preoperative, postoperative periods. There was no significant difference between RDUS parameters of the ipsilateral and contralateral kidneys in preoperative or postoperative periods. PSV and EDV values were significantly higher in the 1st postoperative month in the group without preoperative DJ stent than in the group with DJ stent (p = 0,031, p = 0,041, respectively). However, RI values were similar. The mean RI were below the threshold value of 0.7 in each period. Conclusion: RDUS parameters didn't show a significant difference in children. Endoscopic surgeries can be safely performed in pediatric stone disease. [ABSTRACT FROM AUTHOR]

Objective. Modern medical imaging plays a vital role in clinical practice, enabling non-invasive visualization of anatomical structures. Dynamic contrast enhancement (DCE) imaging is a technique that uses contrast agents to visualize blood flow dynamics in a time-resolved manner. It can be applied to different modalities, such as computed tomography (CT) and electrical impedance tomography (EIT). This study aims to develop a common theoretical and practical hemodynamic extraction basis for DCE modelling across modalities, based on the gamma-variate function. Approach. The study introduces a framework to generate time-intensity curves for multiple DCE imaging modalities from user-defined hemodynamic parameters. Thus, extensive datasets were simulated for both DCE-CT and EIT, representing different hemodynamic scenarios. Additionally, gamma-variate extensions to account for several physiological effects were detailed in a modality-agnostic manner, and three corresponding fitting strategies, namely nonlinear, linear, and a novel hybrid approach, were implemented and compared on the basis of accuracy of parameter estimation, first pass reconstruction, speed of computation, and failure rate. Main results. As a result, we found the linear method to be the most modality-dependent, exhibiting the greatest bias, variance and failure rates, although remaining the fastest alternative. The hybrid method at least matches the state-of-the-art nonlinear method's accuracy, while improving its robustness and speed by 10 times. Significance. Our research suggests that the hybrid method may bring noteworthy accuracy and efficiency improvements in handling the high-dimensionality of DCE imaging in general, being a step towards real-time processing. Moreover, our generative model presents a potential asset to produce benchmarking and data augmentation datasets across modalities. [ABSTRACT FROM AUTHOR]

Key points Heart failure with preserved ejection fraction (HFpEF) has been characterized by lower blood flow to exercising limbs and lower peak oxygen utilization (V̇O2${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$), possibly associated with disease‐related changes in sympathetic (α‐adrenergic) signaling. Thus, in seven patients with HFpEF (70 ± 6 years, 3 female/4 male) and seven controls (CON) (66 ± 3 years, 3 female/4 male), we examined changes (%Δ) in leg blood flow (LBF, Doppler ultrasound) and leg V̇O2${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ to intra‐arterial infusion of phentolamine (PHEN, α‐adrenergic antagonist) or phenylephrine (PE, α1‐adrenergic agonist) at rest and during single‐leg knee‐extension exercise (0, 5 and 10 W). At rest, the PHEN‐induced increase in LBF was not different between groups, but PE‐induced reductions in LBF were lower in HFpEF (−16% ± 4% vs. −26% ± 5%, HFpEF vs. CON; P < 0.05). During exercise, the PHEN‐induced increase in LBF was greater in HFpEF at 10 W (16% ± 8% vs. 8% ± 5%; P < 0.05). PHEN increased leg V̇O2${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ in HFpEF (10% ± 3%, 11% ± 6%, 15% ± 7% at 0, 5 and 10 W; P < 0.05) but not in controls (−1% ± 9%, −4% ± 2%, −1% ± 5%; P = 0.24). The ‘magnitude of sympatholysis’ (PE‐induced %Δ LBF at rest – PE‐induced %Δ LBF during exercise) was lower in patients with HFpEF (−6% ± 4%, −6% ± 6%, −7% ± 5% vs. −13% ± 6%, −17% ± 5%, −20% ± 5% at 0, 5 and 10 W; P < 0.05) and was positively related to LBF, leg oxygen delivery, leg V̇O2${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$, and the PHEN‐induced increase in LBF (P < 0.05). Together, these data indicate that excessive α‐adrenergic vasoconstriction restrains blood flow and limits V̇O2${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ of the exercising leg in patients with HFpEF, and is related to impaired functional sympatholysis in this patient group. Sympathetic (α‐adrenergic)‐mediated vasoconstriction is exaggerated during exercise in patients with heart failure with preserved ejection fraction (HFpEF), which may contribute to limitations of blood flow, oxygen delivery and oxygen utilization in the exercising muscle. The ability to adequately attenuate α1‐adrenergic vasoconstriction (i.e. functional sympatholysis) within the vasculature of the exercising muscle is impaired in patients with HFpEF. These observations extend our current understanding of HFpEF pathophysiology by implicating excessive α‐adrenergic restraint and impaired functional sympatholysis as important contributors to disease‐related impairments in exercising muscle blood flow and oxygen utilization in these patients. [ABSTRACT FROM AUTHOR]

An electrocardiogram is a medical examination tool for measuring different patterns of heart blood flow circle either in the form of usual or non-invasive patterns. These patterns are useful for the identification of morbidity condition of the heart especially in certain conditions of heart abnormality and arrhythmia. Myocardial infarction (MI) is one of them that happened due to sudden blockage of blood by the cause of malfunction of heart. In electrocardiography (ECG) intensity of MI is highlighted on the basis of unusual patterns of T wave changes. Various studies have contributed for MI through T wave's classification, but more to the point of T wave has always attracted the ECG researchers. Methodology. This Study is primarily designed for proposing the combination of latest methods that are worked for the solutions of pre-defined research questions. Such solutions are designed in the form of the systematic review process (SLR) by following the Kitchen ham guidance. The literature survey is a two phase's process, at first phase collect the articles that were published in IEEE Xplore, Scopus, science direct and Springer from 2008 to 2023. It consist of steps; the first level is executed by filtrating the articles on the basis of keyword phase of title and abstract filter. Similarly, at two level the manuscripts are scanned through filter of eligibility criteria of articles selection. The last level belongs to the quality assessment of articles, in such level articles are rectified through evaluation of domain experts. Results. Finally, the selected articles are addressed with research questions and briefly discuss these selected state-of-the-art methods that are worked for the T wave classification. These address units behave as solutions to research problems that are highlighted in the form of research questions. Conclusion and future directions. During the survey process for these solutions, we got some critical observations in the form of gaps that reflected the other directions for researchers. In which feature engineering, different dependencies of ECG features and dimensional reduction of ECG for the better ECG analysis are reflection of future directions. [ABSTRACT FROM AUTHOR]

Gray-scale sonography in combination with color Doppler imaging is the imaging modality of choice for evaluating scrotal disease because it delivers excellent spatial resolution and assists in the identification and characterization of scrotal masses. Most Intratesticular lesions usually show hypoechoic, are malignant but benign masses has been reported. The differentiation between malignant and benign lesions is important because the treatment is different. Sonography permits differentiation between intratesticular lesions and extra-testicular lesions. In this article, we review the relevant literature and discuss the sonographic and clinical features of different types of intratesticular hypoechoic masses. Familiarity with the sonographic appearances of benign and malignant testicular lesions may allow specific diagnosis. The patient is scanned in the supine position with a folded towel positioned between the patient's legs to support the scrotum. The penis is positioned over the patient's suprapubic region and draped with a second towel. The scanning is performed with a 5- to 12-MHz linear array transducer. Serial transverse and sagittal images of each testis and epididymis are obtained in addition to at least 1 image showing both testicles for direct comparison of testicular echogenicity, echo texture, and scrotal thickness. Color Doppler sonography is used to assess and document blood flow in the testis. The power level, threshold persistence, and wall filter should adjusted to maximize the detection of blood flow through the field of view. Intratesticular cysts including cysts of the tunica albuginea, tubular ectasia of the rete testis, and testicular cysts. Testicular cysts have the typical appearance of other cysts, well defined anechoic structures with increased through transmission. Tubular ectasia of the rete testis showed as hypoechoic branching cystic configurations in the mediastinum testis. These findings may be associated with a spermatocele in the same size. [ABSTRACT FROM AUTHOR]

It is unclear whether muscle blood flow (MBF) is altered in long-term Hodgkin lymphoma (HL) survivors. We tested the hypothesis that 1) MBF response during mental stress (MS) is impaired in long-term HL survivors and 2) aerobic exercise training combined with local strength exercise (ET) restores MBF responses during MS in these survivors. Eighteen 5-year HL survivors and 10 aged-paired healthy subjects (HC) were studied. Twenty HL survivors were randomly divided into two groups: exercise-trained (HLT, n = 10) and untrained (HLUT, n = 10). Maximal aerobic capacity was evaluated by a cardiopulmonary exercise test and forearm blood flow (FBF) by venous occlusion plethysmography. MS was elicited by Stroop color and word test. ET was conducted for 4 mo, 3/wk for 60 min each session. The aerobic exercise intensity corresponded to anaerobic threshold up to 10% below the respiratory compensation point. The strength exercises consisted of two to three sets of chest press, pulley and squat exercises, 12–15 repetitions each exercise at 30–50% of the maximal voluntary contraction. Baseline was similar in HL survivors and HC, except peak oxygen consumption (peak V̇ o 2, P = 0.013) and FBF (P = 0.006) that were lower in the HL survivors. FBF responses during MS were lower in HL survivors (P < 0.001). ET increased peak V̇ o 2 (11.59 ± 3.07%, P = 0.002) and FBF at rest (33.74 ± 5.13%, P < 0.001) and during MS (24 ± 5.31%, P = 0.001). Further analysis showed correlation between the changes in peak V̇ o 2 and the changes in FBF during MS (r = 0.711, P = 0.001). In conclusion, long-term HL survivors have impaired MBF responses during MS. ET restores MBF responses during MS. NEW & NOTEWORTHY: Long-term Hodgkin lymphoma (HL) survivors have impaired muscle blood flow responses during mental stress and decreased maximal aerobic capacity. Supervised aerobic exercise training combined with local strength exercises restores muscle blood flow responses during mental stress and maximal aerobic capacity in these survivors. These findings provide evidence of safety and effectiveness of exercise training in HL survivors. Moreover, they highlight the importance of exercise training in the treatment of this set of patients. [ABSTRACT FROM AUTHOR]

Purpose: The tensor fasciae latae (TFL) muscle is supplied by the lateral femoral circumflex artery (LCFA), arising from the deep femoral artery. However, it has been noted that there is also a consistent vascular anastomotic network. The aim of this study was to describe the accessory vascularization of the TFL muscle through a descriptive anatomical study, in order to hypothesize the feasibility of harvesting a TFL flap in the event of an injury to the main pedicle. In addition, we illustrate this hypothesis with a successful clinical case of Scarpa freconstruction following ligature of the deep femoral artery. Methods: The description of the accessory vascularization was obtained by injecting dye into seven lateral femoral circumflex arteries (LCFA), six superficial circumflex iliac arteries (SCIA), and three inferior gluteal arteries (IGA). Results: The TFL muscle was vascularized primarily by the LCFA. A vascular anastomotic network with the SCIA and the IGA was observed. After selective injection to the SCIAs and IGAs, the subsequent injection to the LCFA showed a diffusion of the TFL skin paddle with a perforasome overlapping between the different vascular territories. Conclusion: The ascending branch of the lateral femoral circumflex plays a dominant role in the vascularization of the TFL muscle. As a result of a periarticular anastomotic network of the hip, this artery establishes several connections with the proximal arteries. Consequently, in cases where blood flow through the LCFA is interrupted, it should be equally possible to harvest the TFL flap through its accessory vascularization. [ABSTRACT FROM AUTHOR]

Purpose: Assessing renal perfusion in‐vivo is challenging and quantitative information regarding renal hemodynamics is hardly incorporated in medical decision‐making while abnormal renal hemodynamics might play a crucial role in the onset and progression of renal disease. Combining physiological stimuli with rubidium‐82 positron emission tomography/computed tomography (82Rb PET/CT) offers opportunities to test the kidney perfusion under various conditions. The aim of this study is: (1) to investigate the application of a one‐tissue compartment model for measuring renal hemodynamics with dynamic 82Rb PET/CT imaging, and (2) to evaluate whether dynamic PET/CT is sensitive to detect differences in renal hemodynamics in stress conditions compared to resting state. Methods: A one‐tissue compartment model for the kidney was applied to cardiac 82Rb PET/CT scans that were obtained for ischemia detection as part of clinical care. Retrospective data, collected from 17 patients undergoing dynamic myocardial 82Rb PET/CT imaging in rest, were used to evaluate various CT‐based volumes of interest (VOIs) of the kidney. Subsequently, retrospective data, collected from 10 patients (five impaired kidney functions and five controls) undergoing dynamic myocardial 82Rb PET/CT imaging, were used to evaluate image‐derived input functions (IDIFs), PET‐based VOIs of the kidney, extraction fractions, and whether dynamic 82Rb PET/CT can measure renal hemodynamics differences using the renal blood flow (RBF) values in rest and after exposure to adenosine pharmacological stress. Results: The delivery rate (K1) values showed no significant (p = 0.14) difference between the mean standard deviation (SD) K1 values using one CT‐based VOI and the use of two, three, and four CT‐based VOIs, respectively 2.01(0.32), 1.90(0.40), 1.93(0.39), and 1.94(0.40) mL/min/mL. The ratio between RBF in rest and RBF in pharmacological stress for the controls were overall significantly lower compared to the impaired kidney function group for both PET‐based delineation methods (region growing and iso‐contouring), with the smallest median interquartile range (IQR) of 0.40(0.28–0.66) and 0.96(0.62–1.15), respectively (p < 0.05). The K1 of the impaired kidney function group were close to 1.0 mL/min/mL. Conclusions: This study demonstrated that obtaining renal K1 and RBF values using 82Rb PET/CT was feasible using a one‐tissue compartment model. Applying iso‐contouring as the PET‐based VOI of the kidney and using AA as an IDIF is suggested for consideration in further studies. Dynamic 82Rb PET/CT imaging showed significant differences in renal hemodynamics in rest compared to when exposed to adenosine. This indicates that dynamic 82Rb PET/CT has potential to detect differences in renal hemodynamics in stress conditions compared to the resting state, and might be useful as a novel diagnostic tool for assessing renal perfusion. [ABSTRACT FROM AUTHOR]

We sought to investigate possible impaired hyperaemia during dynamic handgrip exercise (HGE) in young healthy individuals who had recovered from COVID‐19. We tested the vascular function in individuals recovered from COVID‐19 using a nitric oxide donor (i.e., sodium nitroprusside; SNP), which could revert a possible impaired endothelial function during HGE. Further, we tested whether individuals who recovered from COVID‐19 would present exaggerated brachial vascular resistance under an adrenergic agonist (i.e., phenylephrine; PHE) stimuli during HGE. Participants were distributed into two groups: healthy controls (Control; men: n = 6, 30 ± 3 years, 26 ± 1 kg/m2; and women: n = 5, 25 ± 1 years, 25 ± 1 kg/m2) and subjects recovered from COVID‐19 (post‐COVID; men: n = 6, 29 ± 3 years, 25 ± 1 kg/m2; and women: n = 10, 32 ± 4 years, 22 ± 1 kg/m2). Participants in the post‐COVID group tested positive (RT‐PCR) 12–14 weeks before the protocol. Heart rate (HR), brachial blood pressure (BP), brachial blood flow (BBF) and vascular conductance (BVC) at rest were not different between groups. The HGE increased HR (Control: Δ9 ± 0.4 bpm; and post‐COVID: Δ11 ± 0.4 bpm) and BP (Control: Δ6 ± 1 mmHg; and post‐COVID: Δ12 ± 0.6 mmHg) in both groups. Likewise, BBF (Control: Δ632 ± 38 ml/min; and post‐COVID: Δ620 ± 27 ml/min) and BVC (Control: Δ6.6 ± 0.4 ml/min/mmHg; and post‐COVID: Δ6.1 ± 0.3 ml/min/mmHg) increased during HGE. SNP did not change HGE‐induced hyperaemia but did decrease BP, which induced a reflex‐related increase in HR. PHE infusion also did not change the HGE‐induced hyperaemia but raised BP and reduced HR. In conclusion, exercise‐induced hyperaemia is preserved in healthy young subjects 12–14 weeks after recovery from COVID‐19 infection. What is the central question of this study?How does vascular function compare during dynamic handgrip exercise in young healthy adult males and females who recovered from COVID‐19?What is the main finding and its importance?No differences were observed in exercise hyperaemia in healthy young adults, males and females, who recovered from COVID‐19 compared to the healthy control group. Vascular function seems to be preserved in individuals 12–14 weeks after COVID‐19 during dynamic handgrip exercise in young healthy adults, males and females. [ABSTRACT FROM AUTHOR]

Purpose: The present study aimed to analyze: 1) the reliability of the tissue saturation index (TSI) and ratings of perceived discomfort (RPD) responses wearing a neoprene practical cuff (PrC), comparing with the responses from traditional (TrC) pneumatic cuffs (study I); 2) the effects of PrC on metabolic (blood lactate concentration, BLC), perceptual (rate of perceived effort, RPE) and kinematic responses at sub-maximal swimming velocities (study II). Methods: Study I; 1) PrC test-retest at rest and during swimming ergometer exercise; 2) BFR at rest with TrC inflated to different percentages of the minimum arterial occlusion pressure (MAOP; 60, 80, 100, 120 and 140%). Test-retest reliability of TSI and RPD was assessed by the intraclass correlation coefficient (ICC) and comparisons among conditions were analyzed by one-way repeated-measures ANOVA. Study II; 1) 50, 200 and 400 m swimming performances; 2) sub-maximal incremental swimming protocol with and without PrC. Two-way repeated measures ANOVA was used to compare all variables during sub-maximal velocities. Results: TSI (ICC = 0.81; 95%CI 0.62–0.91) and RPD (ICC = 0.97; 95%CI 0.94–0.99) were reliable under restricted exercise using PrC. TSI during restricted exercise was lower (p <.001) compared to unrestricted exercise (6.8 ± 6.1% vs. 21.6 ± 8.2% of physiological normalization). PrC showed higher BLC only at or above 91% of critical velocity (p <.03), while stroke rate and RPE were higher (p <.005), and stroke length was lower (p <.03) during all swimming velocities. Conclusion: This easy-to-handle and affordable practical BFR device increased physiological stress at sub-maximal efforts which could be an additional training tool for swimmers. [ABSTRACT FROM AUTHOR]

The transition from concentric primary flow to non-tangential secondary flow of blood was investigated using experimental steady shear rheometry and numerical modelling. The aims were to: assess the difference in secondary flow in a Newtonian versus shear-thinning blood analogue; and measure the secondary flow in the blood. Both experiments and numerical modelling showed that the transition from primary to secondary flow was the same in a Newtonian fluid and a shear-thinning blood analogue. Experiments showed whole blood transitioned to secondary flow at lower modified Reynolds numbers than the Newtonian fluid; and transition was haematocrit dependent with higher RBC concentrations transitioning at lower modified Reynolds numbers. These results indicate that modelling blood as a purely shear-thinning fluid does not predict the correct secondary flow fields in whole blood; non-Newtonian effects beyond shear-thinning behaviour are influential, and incorporating effects such as multiphase contributions and viscoelasticity, yield stress and thixotropy is necessary. [ABSTRACT FROM AUTHOR]

Existing effective treatments for ischemic stroke restore blood supply to the ischemic region using thrombolysis or mechanical removal of clot. However, it is increasingly recognized that successful removal of occlusive thrombus from the large artery—recanalization, may not always be accompanied by successful restoration of blood flow to the downstream tissues—reperfusion. Ultimately, brain tissue survival depends on cerebral perfusion, and a functioning microcirculation. Because capillary diameter is often equal to or smaller than an erythrocyte, microcirculation is largely dependent on erythrocyte rheological (hemorheological) factors such as whole blood viscosity (WBV). Several studies in the past have demonstrated elevated WBV in stroke compared with healthy controls. Also, elevated WBV has shown to be an independent risk factor for stroke. Elevated WBV leads to endothelial dysfunction, decreases nitric oxide-dependent flow-mediated vasodilation, and promotes hemostatic alterations/thrombosis, all leading to microcirculation sludging. Compromised microcirculation further leads to decreased cerebral perfusion. Hence, modulating WBV through pharmacological agents might be beneficial to improve cerebral perfusion in stroke. This review discusses the effect of elevated WBV on endothelial function, hemostatic alterations, and thrombosis leading to reduced cerebral perfusion in stroke. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to establish a risk profile for intraoral wound healing disorders based on measurements of microcirculation in gingival tissues. Materials and methods: Oxygen saturation (SO2) and blood flow in gingival tissues were measured with tissue spectrometry and laser doppler spectroscopy in 37 patients before/after tooth extractions. Patients were assigned to four groups: anamnestically and periodontally healthy patients (n = 7), anamnestically healthy but suffering from periodontitis (n = 10), anamnestically healthy but smoking and suffering from periodontitis (n = 10) and suffering from diabetes and periodontitis (n = 10). Measurements were performed at three different time points: Baseline measurement (T0), one day post extractionem (p.e.) (T1) and seven days p.e. (T2). Results: Baseline SO2 values were higher in control patients (p =.038). This effect was most evident in comparison to smokers suffering from periodontitis (p =.042), followed by diabetics suffering from periodontitis (p =.09). An opposite trend was seen for blood flow. Patients suffering from periodontitis demonstrated higher blood flow values (p =.012). Five patients, which belonged to the group of smokers suffering from periodontitis, showed clinically a delayed wound healing. Conclusion: Differences in SO2 and blood flow of gingival tissue could be detected in different groups of patients with existing periodontitis compared to control patients. Clinical Relevance: Lower baseline SO2 values could be a warning signal for possible wound healing disorders after oral surgery. [ABSTRACT FROM AUTHOR]

To compare blood pressure (BP), intraocular pressure (IOP), ophthalmic artery flow (OAF) velocity, retinal nerve fiber layer (RNFL) thickness, and visual fields in newly diagnosed hypertension (HT) patients (before treatment), chronic HT (on antihypertensive medications >5 years) and normotensives. A prospective, cross-sectional study at a tertiary care centre in India. Three groups of 45 patients each: group 1 - early HT, group 2 - chronic HT, and Group 3 - normotensives, underwent evaluation of BP, IOP by Goldmann applanation tonometry (GAT), OAF velocity by transcranial doppler (TCD), RNFL analysis by spectral-domain optical coherence tomography (SD-OCT), and visual fields. The BP was highest in early HT > chronic HT > normotensives (p < 0.001). The IOP of early HT, chronic HT, and normotensives were 15.87 ± 2.19 mmHg, 13.47 ± 1.92 mmHg, and 15.67 ± SD 1.75 mmHg (p < 0.001). The OAF velocity [peak systolic velocity (PSV), end-diastolic velocity (EDV) in cm/sec] was lowest in chronic HT (30.80 ± 7.05, 8.58 ± 1.58) < early HT (35.47 ± 5.34, 10.02 ± 1.74) < normotensives (36.29 ± 4.43, 10.44 ± 2.29), (p < 0.001). The average RNFL thickness was significantly lower in chronic HT (p = 0.022). The PSV, EDV, and MFV showed significant correlation with IOP (r = 0.247, p = 0.004; r = 0.206, p = 0.016; r = 0.266, p = 0.002) and average RNFL thickness (r = 0.309, p= <0.001; r = 0.277, p = 0.001; r = 0.341, p < 0.001) Patients with chronic HT demonstrated the lowest retrobulbar flows, IOP and lower RNFL measurements. Lower ocular perfusion may be associated with lower IOP and may be a risk factor for end-organ damage (RNFL) independent of IOP. [ABSTRACT FROM AUTHOR]

Bench surgery for the preparation of deceased donor pancreatic grafts is labor-intensive and time-consuming. We hypothesized that energy devices could be used during bench surgery to decrease the bench surgery time. However, because bench surgery has two unique characteristics, wet conditions and no blood flow in the vessels, it is necessary to verify the safety and efficacy under such conditions. In an animal tissue model, we validated both ultrasonic and bipolar energy devices: Harmonic Shears and the LigaSure (LS) vessel-sealing device by evaluating heat spread and pressure resistance under bench surgery conditions. In a clinical evaluation of the LS, we compared the outcomes of 22 patients in two different bench surgery groups: with and without the use of the LS. Clinically, the bench surgery time was significantly shorter in the LS group than that in the conventional group (P < 0.001). In the animal tissue experiments, the highest temperature in bench surgery conditions was 60.4°C after 1 s at a 5-mm distance in the LS group. Pressure resistance of ≥ 750 mmHg was achieved in almost all trials in both veins and arteries, with no difference between Harmonic Shears and LS. There was more surgical smoke visually in bench conditions versus in dry conditions and under half bite versus full bite conditions. The encouraging results of our exploratory clinical and animal studies of the energy devices suggest that they may be useful in the setting of bench surgery. [ABSTRACT FROM AUTHOR]

Acute and chronic sodium–glucose cotransporter 2 (SGLT-2) inhibition increases endogenous glucose production (EGP). However, the organ—liver versus kidney—responsible for the increase in EGP has not been identified. In this study, 20 subjects with type 2 diabetes (T2D) and 12 subjects with normal glucose tolerance (NGT) received [3-3H]glucose infusion (to measure total EGP) combined with arterial and renal vein catheterization and para -aminohippuric acid infusion for determination of renal blood flow. Total EGP, net renal arteriovenous balance, and renal glucose production were measured before and 4 h after dapagliflozin (DAPA) and placebo administration. Following DAPA, EGP increased in both T2D and NGT from baseline to 240 min, 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 NGT or 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 renal glucose uptake was entirely explained by the increase in glucosuria. A single dose of DAPA significantly increased EGP, which primarily is explained by an increase in hepatic glucose production, establishing the existence of a novel renal-hepatic axis. Article Highlights: Sodium–glucose cotransporter 2 (SGLT2) inhibitors increase endogenous glucose production (EGP) but the organ—liver versus kidney—responsible for the increase in EGP is unknown. Total EGP ([3-3H]glucose), net renal arteriovenous balance (renal vein catheterization), and renal glucose production were measured in 20 subjects with type 2 diabetes (T2D) and 12 subjects with normal glucose tolerance (NGT) before and 4 h after dapagliflozin and placebo administration. Dapagliflozin increased EGP in both T2D and NGT subjects. All of the increase in EGP was derived from an increase in hepatic glucose output. These results establish the existence of a novel renal-hepatic axis. [ABSTRACT FROM AUTHOR]

Background: A critical parameter of extracorporeal CO2 removal (ECCO2R) applications is the CO2 removal rate (VCO2). Low‐flow venovenous extracorporeal support with large‐size membrane lung remains undefined. This study aimed to evaluate the VCO2 of a low‐flow ECCO2R with large‐size membrane lung using a renal replacement therapy platform in an experimental animal model. Methods: Twelve healthy pigs were placed under mechanical ventilation and connected to an ECCO2R‐CRRT system (surface area = 1.8 m2; OMNIset®, BBraun, Germany). Respiratory settings were reduced to induce two degrees of hypercapnia. VCO2 was recorded under different combinations of PaCO2 (50–69 or 70–89 mm Hg), extracorporeal blood flow (ECBF; 200 or 350 mL/min), and gas flow (4, 6, or 10 L/min). Results: VCO2 increased with ECBF at all three gas flow rates. In severe hypercapnia, the increase in sweep gas flow from 4 to 10 L/min increased VCO2 from 86.38 ± 7.08 to 96.50 ± 8.71 mL/min at an ECBF of 350 mL/min, whereas at ECBF of 200 mL/min, any increase was less effective. But in mild hypercapnia, the increase in sweep gas flow result in significantly increased VCO2 at two ECBF. VCO2 increased with PaCO2 from 50–69 to 70–89 mm Hg at an ECBF of 350 mL/min, but not at ECBF of 200 mL/min. Post‐membrane lung PCO2 levels were similar for different levels of premembrane lung PCO2 (p = 0.08), highlighting the gas exchange diffusion efficacy of the membrane lung in gas exchange diffusion. In severe hypercapnia, the reduction of PaCO2 elevated from 11.5% to 19.6% with ECBF increase only at a high gas flow of 10 L/min (p < 0.05) and increase of gas flow significantly reduced PaCO2 only at a high ECBF of 350 mL/min (p < 0.05). Conclusions: Low‐flow venovenous extracorporeal ECCO2R‐CRRT with large‐size membrane lung is more efficient with the increase of ECBF, sweep gas flow rate, and the degree of hypercapnia. The influence of sweep gas flow on VCO2 depends on the ECBF and degree of hypercapnia. Higher ECBF and gas flow should be chosen to reverse severe hypercapnia. [ABSTRACT FROM AUTHOR]

Intracranial aneurysms are nowadays treated with endovascular flow diverter devices to avoid sac rupture. This study explores how different linear and quadratic hydrodynamic resistance parameters reduce the flow in the sac for five patient-specific sidewall aneurysms.The 125 performed blood flow simulations included the stents using a Darcy-Forcheimer porous layer approach based on real-life stent characteristics. Time- and space-averaged velocity magnitudes were strongly affected by the linear coefficient with a power-law relationship. Quadratic coefficients alter the flow in a minor way due to the low-velocity levels in the aneurysm sac and neck region. [ABSTRACT FROM AUTHOR]

Background: The association of aspirin loading with the risk of coronary no‐reflow (CNR) after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) has not been investigated. We assessed the association of aspirin loading before PCI with CNR in patients with AMI. Materials and Methods: This study included 3100 patients with AMI undergoing PCI. Of them, 2812 patients received aspirin loading (a single oral [or chewed] or intravenous dose of 150–300 mg) and 288 patients did not receive aspirin loading before PCI. The primary endpoint was CNR, defined as Thrombolysis in Myocardial Infarction blood flow grade of <3 after the PCI. Results: CNR occurred in 130 patients: 127 patients in the group with aspirin loading and 3 patients in the group without aspirin loading before PCI (4.5% vs. 1.0%; odds ratio [OR] = 4.50, 95% confidence interval, [1.42–14.21], p = 0.005). After adjustment, the association between aspirin loading and CNR was significant (adjusted OR = 4.49 [1.56–12.92]; p < 0.001). There was no aspirin loading‐by‐P2Y12 inhibitor (ticagrelor or prasugrel) interaction (pint = 0.465) or aspirin loading‐by‐chronic aspirin therapy on admission (pint = 0.977) interaction with respect to the occurrence of CNR after PCI. Chronic low‐dose aspirin therapy on admission was not independently associated with higher risk of CNR after PCI (adjusted OR = 1.06 [0.65–1.72]; p = 0.824). Conclusion: In patients with AMI undergoing PCI, aspirin loading before the PCI procedure at the guideline‐recommended doses was associated with higher odds of developing CNR. However, due to the limited number of events, the findings should be considered as hypothesis generating. [ABSTRACT FROM AUTHOR]

Background: Atopic dermatitis (AD) is a highly prevalent inflammatory skin disorder characterized by episodic exacerbations and remissions. Why the clinically healthy skin of AD patients becomes rapidly inflamed and very pruritic is poorly understood. Objective: To investigate cowhage‐ and histamine‐induced itch and skin expression levels of their target receptors in lesional and non‐lesional skin of AD, compared to the skin of patients with psoriasis, chronic spontaneous urticaria (CSU) and healthy subjects. Methods: Patients with AD, psoriasis and chronic spontaneous urticaria (CSU) as well as healthy control subjects (HC) (n = 20 each) were assessed for differences in itch parameters, neurogenic flare reaction and local blood flow responses to skin provocations with cowhage and histamine. Skin biopsies from 10 AD, 10 psoriasis,11 CSU and 12 HC were obtained to assess expression of protease‐activated receptors 2 and 4 (PAR‐2, PAR‐4), histamine H1 and H4 receptors (H1R, H4R), and mast cells. Results: Provocation of non‐lesional skin of AD patients with cowhage resulted in prolonged itch (p = 0.020), which was not observed in psoriasis and CSU. Significantly prolonged and more intense cowhage‐ and histamine‐induced itch (for duration, peak and overall intensity) was also observed in lesional AD skin. Diminished neurogenic flare reaction and blood flow after histamine provocation were shown in AD and psoriasis patients. Non‐lesional AD skin along with lesional AD and psoriasis skin showed an increased expression of PAR‐2 and PAR‐4, H1R and H4R. Mast cell number was higher in lesional AD and psoriasis skin (p = 0.006 and p = 0.006, respectively). Conclusion: The non‐lesional skin of AD patients markedly differs from healthy skin in cowhage‐induced itch responses and the expression of receptors for proteases and histamine. Proactive therapeutic interventions that downregulate these receptors may prevent episodic exacerbation in AD. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of blood flow restriction (BFR) on electromyographic amplitude (EMGRMS)–force relationships of the biceps brachii (BB) during a single high-load muscle action. Methods: Twelve recreationally active males and eleven recreationally active females performed maximal voluntary contractions (MVCs), followed by an isometric trapezoidal muscle action of the elbow flexors at 70% MVC. Surface EMG was recorded from the BB during BFR and control (CON) visits. For BFR, cuff pressure was 60% of the pressure required to completely occlude blood at rest. Individual b (slope) and a terms (gain) were calculated from the log-transformed EMGRMS–force relationships during the linearly increasing and decreasing segments of the trapezoid. EMGRMS during the steady force segment was normalized to MVC EMGRMS. Results: For BFR, the b terms were greater during the linearly increasing segment than the linearly decreasing segment (p < 0.001), and compared to the linearly increasing segment for CON (p < 0.001). The a terms for BFR were greater during the linearly decreasing than linearly increasing segment (p = 0.028). Steady force N-EMGRMS was greater for BFR than CON collapsed across sex (p = 0.041). Conclusion: BFR likely elicited additional recruitment of higher threshold motor units during the linearly increasing- and steady force-segment. The differences between activation and deactivation strategies were only observed with BFR, such as the b terms decreased and the a terms increased for the linearly decreasing segment in comparison to the increasing segment. However, EMGRMS–force relationships during the linearly increasing- and decreasing-segments were not different between sexes during BFR and CON. [ABSTRACT FROM AUTHOR]

Blood flow to the brain is a critical physiological function and is useful to monitor in critical care settings. Despite that, a surrogate is most likely measured instead of actual blood flow. Such surrogates include velocity measurements in the carotid artery and systemic blood pressure, even though true blood flow can actually be obtained using MRI and other modalities. Ultrasound is regularly used to measure blood flow and is, under certain conditions, able to provide quantitative volumetric blood flow in milliliters per minute. Unfortunately, most times the resulting flow data is not valid due to unmet assumptions (such as flow profile and angle correction). Color flow, acquired in three dimensions, has been shown to yield quantitative blood flow without any assumptions (3DVF). Here we are testing whether color flow can perform during physiological conditions common to severe injury. Specifically, we are simulating severe traumatic brain injury (epidural hematoma) as well as hemorrhagic shock with 50% blood loss. Blood flow was measured in the carotid artery of a cohort of 7 Yorkshire mix pigs (40–60 kg) using 3DVF (4D16L, LOGIQ 9, GE HealthCare, Milwaukee, WI, USA) and compared to an invasive flow meter (TS420, Transonic Systems Inc., Ithaca, NY, USA). Six distinct physiological conditions were achieved: baseline, hematoma, baseline 2, hemorrhagic shock, hemorrhagic shock plus hematoma, and post-hemorrhage resuscitation. Mean cerebral oxygen extraction ratio varied from 40.6% ± 13.0% of baseline to a peak of 68.4% ± 15.6% during hemorrhagic shock. On average 3DVF estimated blood flow with a bias of -9.6% (-14.3% root mean squared error) relative to the invasive flow meter. No significant flow estimation error was detected during phases of flow reversal, that was seen in the carotid artery during traumatic conditions. The invasive flow meter showed a median error of -11.5% to 39.7%. Results suggest that absolute volumetric carotid blood flow to the brain can be obtained and potentially become a more specific biomarker related to cerebral hemodynamics than current surrogate markers. [ABSTRACT FROM AUTHOR]

The nutrient artery provides ~50%–70% of the total blood volume to long bones in mammals. Studying the functional characteristics of this artery in vivo can be difficult and expensive, so most researchers have measured the nutrient foramen, an opening on the outer surface of the bone that served as the entry point for the nutrient artery during development and bone ossification. Others have measured the nutrient canal (i.e., the passage which the nutrient artery once occupied), given that the external dimensions of the foramen do not necessarily remain uniform from the periosteal surface to the medullary cavity. The nutrient canal, as an indicator of blood flow to long bones, has been proposed to provide a link to studying organismal activity (e.g., locomotor behavior) from skeletal morphology. However, although external loading from movement and activity causes skeletal remodeling, it is unclear whether it affects the size or configuration of nutrient canals. To investigate whether nutrient canals can exhibit phenotypic plasticity in response to physical activity, we studied a mouse model in which four replicate high runner (HR) lines have been selectively bred for high voluntary wheel‐running behavior. The selection criterion is the average number of wheel revolutions on days 5 and 6 of a 6‐day period of wheel access as young adults (~6–8 weeks old). An additional four lines are bred without selection to serve as controls (C). For this study, 100 female mice (half HR, half C) from generation 57 were split into an active group housed with wheels and a sedentary group housed without wheels for 12 weeks starting at ~24 days of age. Femurs were collected, soft tissues were removed, and femora were micro‐computed tomography scanned at a resolution of 12 μm. We then imported these scans into AMIRA and created 3D models of femoral nutrient canals. We tested for evolved differences in various nutrient canal traits between HR and C mice, plastic changes resulting from chronic exercise, and the selection history‐by‐exercise interaction. We found few differences between the nutrient canals of HR versus C mice, or between the active and sedentary groups. We did find an interaction between selection history and voluntary exercise for the total number of nutrient canals per femur, in which wheel access increased the number of canals in C mice but decreased it in HR mice. Our results do not match those from an earlier study, conducted at generation 11, which was prior to the HR lines reaching selection limits for wheel running. The previous study found that mice from the HR lines had significantly larger total canal cross‐sectional areas compared to those from C lines. However, this discrepancy is consistent with studies of other skeletal traits, which have found differences between HR and C mice to be somewhat inconsistent across generations, including the loss of some apparent adaptations with continued selective breeding after reaching a selection limit for wheel‐running behavior. [ABSTRACT FROM AUTHOR]

Normothermic regional perfusion (NRP) has recently been used to augment organ donation after circulatory death (DCD) to improve the quantity and quality of transplantable organs. In DCD‐NRP, after withdrawal of life‐sustaining therapies and cardiopulmonary arrest, patients are cannulated onto extracorporeal membrane oxygenation to reestablish blood flow to targeted organs including the heart. During this process, aortic arch vessels are ligated to restrict cerebral blood flow. We review ethical challenges including whether the brain is sufficiently reperfused through collateral circulation to allow reemergence of consciousness or pain perception, whether resumption of cardiac activity nullifies the patient's prior death determination, and whether specific authorization for DCD‐NRP is required. ANN NEUROL 2024;95:1035–1039 [ABSTRACT FROM AUTHOR]

Background: Knee osteoarthritis (KOA) is a chronic musculoskeletal disorder characterized by pain and functional impairment. Blood flow restriction (BFR) with low-load resistance training (LLRT) demonstrates a similar improvement in clinical outcomes to high-load resistance training (HLRT) in treating KOA. It has not been established whether intermittent blood flow restriction (iBFR) with LLRT can lead to clinical outcomes that are comparable to those produced by continuous blood flow restriction (cBFR) with LLRT and HLRT. The aim of the proposed study is to evaluate the efficacy of iBFR with LLRT on pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence in KOA patients. Methods: This is a three-arm, non-inferiority, randomized controlled trial utilizing blinded assessors. Two hundred thirteen participants will be randomly allocated to one of the following three groups: iBFR group—receiving 4 months of LLRT with iBFR, twice weekly (n = 71); cBFR group—receiving 4 months of LLRT with cBFR, twice weekly (n = 71); or HLRT group—receiving 4 months of HLRT without BFR, twice weekly (n = 71). The primary outcome is pain. The secondary outcomes include the WOMAC, muscle strength, muscle mass, physical function, perceptions of discomfort and effort, and adherence. Pain and WOMAC will be measured at the baseline and 4 and 12 months after randomizations. Muscle strength, muscle mass, and physical function will be measured at the baseline and 4 months after randomizations. The perceptions of discomfort and effort will be measured during the first and final sessions. Discussion: BFR with LLRT has a similar improvement in clinical outcomes as HLRT. However, cBFR may cause elevated ratings of perceived exertion and local discomfort, compromising patient tolerability and treatment adherence. If iBFR with LLRT could produce improvement in clinical outcomes analogous to those of HLRT and iBFR with LLRT, it could be considered an alternative approach for treating patients with KOA. Trial registration: Chinese Clinical Trial Registry ChiCTR2300072820. Registered on June 26, 2023. [ABSTRACT FROM AUTHOR]

Background: Exploring the relationship between oxygen supply and myelin damage would benefit from a simultaneous quantification of myelin and cerebral blood flow (CBF) in the brain's white matter (WM). To validate an analytical method for quantifying both CBF and myelin content in the WM using dynamic [11C]PiB positron emission tomography (PET). Methods: A test-retest study was performed on eight healthy subjects who underwent two consecutive dynamic [11 C]PiB-PET scans. Three quantitative approaches were compared: simplified reference tissue model 2 (SRTM2), LOGAN graphical model, and standardized uptake value ratio (SUVR). The sensitivity of methods to the size of the region of interest was explored by simulating lesion masks obtained from 36 subjects with multiple sclerosis. Reproducibility was assessed using the relative difference and interclass correlation coefficient. Repeated measures correlations were used to test for cross-correlations between metrics. Results: Among the CBF measures, the relative delivery (R1) of the simplified reference tissue model 2 (SRTM2) displayed the best reproducibility in the white matter, with a strong influence of the size of regions analyzed, the test-retest variability being below 10% for regions above 68 mm3 in the supratentorial white matter. [11C]PiB PET-derived proxies of CBF demonstrated lower perfusion of white matter compared to grey matter with an overall ratio equal to 1.71 ± 0.09 when the SRTM2-R1 was employed. Tissue binding in the white matter was well estimated by the Logan graphical model through estimation of the distribution volume ratio (LOGAN-DVR) and SRTM2 distribution volume ratio (SRTM2-DVR), with test-retest variability being below 10% for regions exceeding 106 mm3 for LOGAN-DVR and 300 mm3 for SRTM2-DVR. SRTM2-DVR provided a better contrast between white matter and grey matter. The interhemispheric variability was also dependent on the size of the region analyzed, being below 10% for regions above 103 mm3 for SRTM2-R1 and above 110 mm3 for LOGAN-DVR. Whereas the 1 to 8-minute standardized uptake value ratio (SUVR1-8) showed an intermediary reproducibility for CBF assessment, SUVR0-2 for perfusion or SUVR50-70 for tissue binding showed poor reproducibility and correlated only mildly with SRTM2-R1 and LOGAN-DVR estimations respectively. Conclusions: [11C]PiB PET imaging can simultaneously quantify perfusion and myelin content in WM diseases associated with focal lesions. For longitudinal studies, SRTM2-R1 and DVR should be preferred over SUVR for the assessment of regional CBF and myelin content, respectively. Trial registration: European Union Clinical Trials Register EUDRACT; EudraCT Number: 2008-004174-40; Date: 2009-03-06; https//www.clinicaltrialsregister.eu; number 2008-004174-40. [ABSTRACT FROM AUTHOR]

Recent progresses in intravital imaging have enabled highly-resolved measurements of periarteriolar oxygen gradients (POGs) within the brain parenchyma. POGs are increasingly used as proxies to estimate the local baseline oxygen consumption, which is a hallmark of cell activity. However, the oxygen profile around a given arteriole arises from an interplay between oxygen consumption and delivery, not only by this arteriole but also by distant capillaries. Integrating such interactions across scales while accounting for the complex architecture of the microvascular network remains a challenge from a modelling perspective. This limits our ability to interpret the experimental oxygen maps and constitutes a key bottleneck toward the inverse determination of metabolic rates of oxygen. We revisit the problem of parenchymal oxygen transport and metabolism and introduce a simple, conservative, accurate and scalable direct numerical method going beyond canonical Krogh-type models and their associated geometrical simplifications. We focus on a two-dimensional formulation, and introduce the concepts needed to combine an operator-splitting and a Green's function approach. Oxygen concentration is decomposed into a slowly-varying contribution, discretized by Finite Volumes over a coarse cartesian grid, and a rapidly-varying contribution, approximated analytically in grid-cells surrounding each vessel. Starting with simple test cases, we thoroughly analyze the resulting errors by comparison with highly-resolved simulations of the original transport problem, showing considerable improvement of the computational-cost/accuracy balance compared to previous work. We then demonstrate the model ability to flexibly generate synthetic data reproducing the spatial dynamics of oxygen in the brain parenchyma, with sub-grid resolution. Based on these synthetic data, we show that capillaries distant from the arteriole cannot be overlooked when interpreting POGs, thus reconciling recent measurements of POGs across cortical layers with the fundamental idea that variations of vascular density within the depth of the cortex may reveal underlying differences in neuronal organization and metabolic load. Author summary: The cerebral microvascular network is the logistics system that provides energy to brain cells at the right time and place. Blood flow and oxygen can now be observed dynamically in living rodents, which transformed our knowledge of the system and its role in ageing and disease. However, oxygen concentration at a given location is the result of a subtle balance between local cellular consumption, supply by neighboring vessels and their interconnections to distant ones. Thus, measurements are difficult to interpret without integrating this multi-scale component, which requires advanced computational models. This hinders our ability to bridge the gap between experiments in rodents and clinical applications in humans. In this work, we focus on oxygen transport between vessels, leveraging recent advances in multi-scale modelling and their mathematical foundations. By this way, we formulate for the first time a simple, conservative, accurate and scalable computational model for cerebral oxygen across scales, that is able to integrate the spatially heterogenous distribution of vessels. We illustrate how this model, combined to imaging, will pave the way towards better estimates of oxygen consumption, a hallmark of neural activity that cannot be directly measured. [ABSTRACT FROM AUTHOR]

The lie-detection tests are traditionally carried out by well-trained experts using polygraph machines. However, it is time-consuming, invasive, and, overall, a cumbersome process, not admissible by the court of law. Trained individuals can easily flaunt these tests. On the other hand, facial thermal imaging could be more effective as it is noninvasive and could be a stealth method of tracking the facial blood flow patterns, which have been proven to detect deceit. This paper presents a method based on facial thermal imaging to detect deception in human subjects. The major issue in such research is the lack of proper real-life databases which emulate the crime scenes. In this paper, first, we have developed a database based on almost real-life theft incidents with due diligence using isolated subjects over a period of time at a government hospital under the plea of free health checkup. The experiment has been conducted at Midnapore Medical College and Hospital, West Bengal, India, with proper ethical committee approval. The participants are selected at the behest of the police department with habitual crime records. Most of them have been repeatedly charged with petty crimes of pick-pocketing and stealing. They are invited individually at different instances of time under the plea of medical checkup where they have been enticed to steal cash. It is followed by a two-stage process, a friendly interaction followed by a slightly tougher interrogation. Their forehead and periorbital region skin surface temperature are recorded by a hidden thermal camera. Upon analysis, conspicuous changes in the temperature profile and blood flow pattern have been observed in the individuals who stole money and those who did not. [ABSTRACT FROM AUTHOR]

The microvasculature facilitates gas exchange, provides nutrients to cells, and regulates blood flow in response to stimuli. Vascular abnormalities are an indicator of pathology for various conditions, such as compromised vessel integrity in small vessel disease and angiogenesis in tumors. Traditional immunohistochemistry enables the visualization of tissue cross-sections containing exogenously labeled vasculature. Although this approach can be utilized to quantify vascular changes within small fields of view, it is not a practical way to study the vasculature on the scale of whole organs. Three-dimensional (3D) imaging presents a more appropriate method to visualize the vascular architecture in tissue. Here we describe the complete protocol that we use to characterize the vasculature of different organs in mice encompassing the methods to fluorescently label vessels, optically clear tissue, collect 3D vascular images, and quantify these vascular images with a semi-automated approach. To validate the automated segmentation of vascular images, one user manually segmented one hundred random regions of interest across different vascular images. The automated segmentation results had an average sensitivity of 83±11% and an average specificity of 91±6% when compared to manual segmentation. Applying this procedure of image analysis presents a method to reliably quantify and characterize vascular networks in a timely fashion. This procedure is also applicable to other methods of tissue clearing and vascular labels that generate 3D images of microvasculature. [ABSTRACT FROM AUTHOR]

BACKGROUND: Blood flow restriction training has broad application prospects in improving limb muscle strength. It has ideal effects on the upper limbs is ideal, and the specific application scheme has high research value. OBJECTIVE: To explain the influence of blood flow restriction training on the fitness benefits of upper limb muscles and summarize the specific programs of blood flow restriction training for upper limb, attempting to give suggestions on application programs based on existing studies. METHODS: Literature on the application of upper limb blood flow restriction training were searched in CNKI, WanFang, VIP, CBM, PubMed, Embase, EBSCO, Cochrane Library and Web of Science databases. The search terms were “blood flow restriction, blood flow restriction training, pressure training, upper limb, upper arm, forearm, arm, forearm” in Chinese and “blood flow restriction training, blood flow restriction exercise, blood flow restriction therapy, BFR therapy, occlusion training, KAATSU training, BFRT, upper extremity, upper limb, arm, forearm” in English. The relevant articles on the application of blood flow restriction training in the upper limbs included in the database from database inception to December 2022 were selected and screened according to inclusion criteria and exclusion criteria. RESULTS AND CONCLUSION: Firstly, blood flow restriction training is mainly applied to healthy people, special athletes and people with upper limb injury. Secondly, the influence of blood flow restriction training on upper limb muscle fitness is mainly reflected in the increase of upper limb circumference, muscle strength, muscle endurance, muscle thickness, muscle cross-sectional area and explosive power of upper limb, followed by the cross migration phenomenon of the upper limbs. Thirdly, blood flow restriction training for the upper limbs mainly uses inflatable blood flow restriction devices: the cuff width was 3-5 cm, the pressure position was 1/3 of the upper arm, the limiting pressure was 40%-60% arterial occlusion pressure or 80-160 mmHg, the training load is 20%-30% 1RM, the training volume is four sessions (30-15-15-15 times), the interval time was 30-60 seconds, and the training frequency was 2 or 3 times per week. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD) is associated with impaired cerebral circulation which underscores diminished delivery of blood oxygen and nutrients to and throughout the brain. In the 3xTg-AD mouse model, we have recently found that > 10 cerebrovascular miRNAs pertaining to vascular permeability, angiogenesis, and inflammation (e.g., let-7d, miR-99a, miR-132, miR-133a, miR-151-5p, and miR-181a) track early development of AD. Further, endothelial-specific miRNAs (miR-126-3p, miR-23a/b, miR-27a) alter with onset of overall AD pathology relative to stability of smooth muscle/pericyte-specific miRNAs (miR-143, miR-145). Objective: We tested the hypothesis that cerebrovascular miRNAs indicating AD pathology share mRNA targets that regulate key endothelial cell functions such as angiogenesis, vascular permeability, and blood flow regulation. Methods: As detected by NanoString nCounter miRNA Expression panel for 3xTg-AD mice, 61 cerebrovascular miRNAs and respective mRNA targets were examined using Ingenuity Pathway Analysis for canonical Cardiovascular (Cardio) and Nervous System (Neuro) Signaling. Results: The number of targets regulated per miRNA were 21±2 and 33±3 for the Cardio and Neuro pathways respectively, whereby 14±2 targets overlap among pathways. Endothelial miRNAs primarily target members of the PDE, PDGF, SMAD, and VEGF families. Individual candidates regulated by≥4 miRNAs that best mark AD pathology presence in 3xTg-AD mice include CFL2, GRIN2B, PDGFB, SLC6A1, SMAD3, SYT3, and TNFRSF11B. Conclusion: miRNAs selective for regulation of endothelial function and respective downstream mRNA targets support a molecular basis for dysregulated cerebral blood flow regulation coupled with enhanced cell growth, proliferation, and inflammation. [ABSTRACT FROM AUTHOR]

Passive whole‐body hyperthermia increases limb blood flow and cardiac output (Q̇$\dot Q$), but the interplay between peripheral and central thermo‐haemodynamic mechanisms remains unclear. Here we tested the hypothesis that local hyperthermia‐induced alterations in peripheral blood flow and blood kinetic energy modulate flow to the heart and Q̇$\dot Q$. Body temperatures, regional (leg, arm, head) and systemic haemodynamics, and left ventricular (LV) volumes and functions were assessed in eight healthy males during: (1) 3 h control (normothermic condition); (2) 3 h of single‐leg heating; (3) 3 h of two‐leg heating; and (4) 2.5 h of whole‐body heating. Leg, forearm, and extracranial blood flow increased in close association with local rises in temperature while brain perfusion remained unchanged. Increases in blood velocity with small to no changes in the conduit artery diameter underpinned the augmented limb and extracranial perfusion. In all heating conditions, Q̇$\dot Q$ increased in association with proportional elevations in systemic vascular conductance, related to enhanced blood flow, blood velocity, vascular conductance and kinetic energy in the limbs and head (all R2 ≥ 0.803; P < 0.001), but not in the brain. LV systolic (end‐systolic elastance and twist) and diastolic functional profiles (untwisting rate), pulmonary ventilation and systemic aerobic metabolism were only altered in whole‐body heating. These findings substantiate the idea that local hyperthermia‐induced selective alterations in peripheral blood flow modulate the magnitude of flow to the heart and Q̇$\dot Q$ through changes in blood velocity and kinetic energy. Localised heat‐activated events in the peripheral circulation therefore affect the human heart's output. Key points: Local and whole‐body hyperthermia increases limb and systemic perfusion, but the underlying peripheral and central heat‐sensitive mechanisms are not fully established.Here we investigated the regional (leg, arm and head) and systemic haemodynamics (cardiac output: Q̇$\dot Q$) during passive single‐leg, two‐leg and whole‐body hyperthermia to determine the contribution of peripheral and central thermosensitive factors in the control of human circulation.Single‐leg, two‐leg, and whole‐body hyperthermia induced graded increases in leg blood flow and Q̇$\dot Q$. Brain blood flow, however, remained unchanged in all conditions. Ventilation, extracranial blood flow and cardiac systolic and diastolic functions only increased during whole‐body hyperthermia.The augmented Q̇$\dot Q$ with hyperthermia was tightly related to increased limb and head blood velocity, flow and kinetic energy.The findings indicate that local thermosensitive mechanisms modulate regional blood velocity, flow and kinetic energy, thereby controlling the magnitude of flow to the heart and thus the coupling of peripheral and central circulation during hyperthermia. [ABSTRACT FROM AUTHOR]

Purpose: We evaluated the impact on cardiovascular outcome of coronary revascularization-induced changes in ischemic total perfusion defect (ITPD) and myocardial flow reserve (MFR) as assessed by 82Rb positron emission tomography (PET)/computed tomography (CT) imaging. Methods: The study included 102 patients referred to 82Rb PET/CT myocardial perfusion imaging before and after coronary revascularization. All patients were followed for the occurrence of cardiovascular events (cardiac death, nonfatal myocardial infarction, repeated revascularization, and heart failure) after the second imaging study. Results: During a median follow-up of 20 months, 21 events occurred. The clinical characteristics were comparable between patients with and without events. In the overall study population, after revascularization, there was a significant reduction (P < 0.001) of ITPD, while hyperemic myocardial blood flow (MBF) (P < 0.01) and MFR (P < 0.05) significantly improved. Event rate was higher in patients with ITPD (P < 0.005) or MFR (P < 0.001) worsening compared to those with unchanged or improved ITPD or MFR. At Cox univariable analysis, ITPD and MFR worsening resulted in predictors of events (both P < 0.05). Patients with worsening of both ITPD and MFR had the worst event-free survival (log-rank 32.9, P for trend < 0.001). Conclusions: In patients with stable CAD, worsening of ITPD and MFR after revascularization procedures is associated with higher risk of cardiovascular events. Follow-up MPI with 82Rb PET/CT may improve risk stratification in patients submitted to coronary revascularization. [ABSTRACT FROM AUTHOR]

Purpose: To prospectively compare changes in myocardial blood flow (MBF) and myocardial flow reserve (MFR) in multivessel coronary artery disease (MVCAD) patients undergoing incomplete revascularization (IR) versus complete revascularization (CR) by coronary artery bypass grafting (CABG). Methods: Seven male patients (age 68 ± 9 years) with MVCAD underwent myocardial perfusion PET/CT with [13N]ammonia before and at least 4 months after CABG. Segmental resting and stress MBF as well as MFR were measured. Resting and during stress left ventricle ejection fraction (LVEF) were also calculated. Results: Three patients (43%) underwent CR and four (57%) IR. Among 119 myocardial segments, 101 (85%) were revascularized, and 18 (15%) were not. After CABG, stress MBF (mL/min/gr) and MFR are significantly increased in all myocardial segments, with a greater increase in the revascularized segments (p = 0.013). In both groups, LVEF significantly decreased during stress at baseline PET (p = 0.04), but not after CABG. Conclusion: Stress MBF and MFR significantly improve after CABG in both revascularized and not directly revascularized myocardial segments. IR strategy may be considered in patients with high surgical risk for CR. [ABSTRACT FROM AUTHOR]

Myopia is a common refractive error that affects a large proportion of the population. Recent studies have revealed that alterations in choroidal thickness (ChT) and choroidal blood flow (ChBF) play important roles in the progression of myopia. Reduced ChBF could affect scleral cellular matrix remodeling, which leads to axial elongation and further myopia progression. As ChT and ChBF could be used as potential biomarkers for the progression of myopia, several recent myopia treatments have targeted alterations in ChT and ChBF. Our review provides a comprehensive overview of the recent literature review on the relationship between ChBF and myopia. We also highlight the importance of ChT and ChBF in the progression of myopia and the potential of ChT as an important biomarker for myopia progression. This summary has significant implications for the development of novel strategies for preventing and treating myopia. [ABSTRACT FROM AUTHOR]

Background: Flap perfusion is a prerequisite for microvascular free flap survival and a parameter routinely used for flap monitoring. The aim of this study was to investigate the influence of the anastomosis recipient vessel on flap perfusion. Methods: Flap perfusion was retrospectively analyzed in 338 patients who underwent head and neck reconstruction with microvascular free flaps between 2011 and 2020. The Oxygen-to-see tissue oxygen analysis system measurements for intraoperative and postoperative flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation at 8 and 2 mm tissue depths were compared between arterial anastomosis recipient vessels (external carotid artery [ECA], facial artery [FAA], lingual artery [LIA], and superior thyroid artery [STA]) and venous anastomosis recipient vessels (internal jugular vein [IJV], combination of IJV and IJV branches, IJV branches, and external jugular vein). Results: The postoperative hemoglobin concentration at 2 mm tissue depth differed significantly between arterial anastomosis recipient vessels (ECA, 41.0 arbitrary units [AU]; FAA, 59.0 AU; LIA, 51.5 AU; STA, 59.0 AU; p = 0.029). This difference did not persist in the multivariable testing (p = 0.342). No other differences in flap blood flow, hemoglobin concentration, or hemoglobin oxygen saturation were observed between the arterial and venous anastomosis recipient vessels (p > 0.05 for all). Conclusions: The arterial and venous recipient vessels used for anastomosis did not influence microvascular free flap perfusion. This underlines the capability of the studied recipient vessels to adequately perfuse free flaps, may explain the observed indifferent flap survival rates between commonly used anastomosis recipient vessels, and implies that the recipient vessel is not a confounding variable for flap monitoring with the Oxygen-to-see tissue oxygen analysis system. Further prospective studies are needed to confirm the findings. [ABSTRACT FROM AUTHOR]

Hypoxic-ischemic encephalopathy (HIE) is a major cause of newborn brain damage stemming from a lack of oxygenated blood flow in the neonatal period. Twenty-five to fifty percent of asphyxiated infants who develop HIE die in the neonatal period, and about sixty percent of survivors develop long-term neurological disabilities. From the first minutes to months after the injury, a cascade of events occurs, leading to blood-brain barrier (BBB) opening, neuronal death and inflammation. To date, the only approach proposed in some cases is therapeutic hypothermia (TH). Unfortunately, TH is only partially protective and is not applicable to all neonates. This review synthesizes current knowledge on the basic molecular mechanisms of brain damage in hypoxia-ischemia (HI) and on the different therapeutic strategies in HI that have been used and explores a major limitation of unsuccessful therapeutic approaches. [ABSTRACT FROM AUTHOR]

Contrast transport models are widely used to quantify blood flow and transport in dynamic contrast-enhanced magnetic resonance imaging. These models analyze the time course of the contrast agent concentration, providing diagnostic and prognostic value for many biological systems. Thus, ensuring accuracy and repeatability of the model parameter estimation is a fundamental concern. In this work, we analyze the structural and practical identifiability of a class of nested compartment models pervasively used in analysis of MRI data. We combine artificial and real data to study the role of noise in model parameter estimation. We observe that although all the models are structurally identifiable, practical identifiability strongly depends on the data characteristics. We analyze the impact of increasing data noise on parameter identifiability and show how the latter can be recovered with increased data quality. To complete the analysis, we show that the results do not depend on specific tissue characteristics or the type of enhancement patterns of contrast agent signal. Author summary: In the last decades, study and quantification of tissue perfusion parameters related to blood flow and transport have acquired a significant importance in the analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). In fact, concentration time course data derived from DCE-MRI are essential elements for many computational biological applications, ranging from tumor grading assessment to prediction of antiangiogenic treatment response. Contrast agent transport models have been developed and widely used for the analysis of this data, providing diagnostic and prognostic value. Thus, there is a need to ensure reliability and reproducibility of the transport model parameter estimations. Here we propose the analysis of structural and practical model identifiability, combining artificial and real data to study the role of noise in parameter estimation. The results provide a mathematical explanation for the lack of repeatability of DCE-MRI quantification as well as emphasize the need for new DCE-MRI acquisition protocols standards and quantification methods. [ABSTRACT FROM AUTHOR]

Molecular characterization of vascular anomalies has revealed that affected endothelial cells (ECs) harbor gain-of-function (GOF) mutations in the gene encoding the catalytic a subunit of PI3Ka (PIK3CA). These PIK3CA mutations are known to cause solid cancers when occurring in other tissues. PIK3CA-related vascular anomalies, or "PIKopathies," range from simple, i.e., restricted to a particular form of malformation, to complex, i.e., presenting with a range of hyperplasia phenotypes, including the PIK3CArelated overgrowth spectrum. Interestingly, development of PIKopathies is affected by fluid shear stress (FSS), a physiological stimulus caused by blood or lymph flow. These findings implicate PI3K in mediating physiological EC responses to FSS conditions characteristic of lymphatic and capillary vessel beds. Consistent with this hypothesis, increased PI3K signaling also contributes to cerebral cavernous malformations, a vascular disorder that affects low-perfused brain venous capillaries. Because the GOF activity of PI3K and its signaling partners are excellent drug targets, understanding PIK3CA's role in the development of vascular anomalies may inform therapeutic strategies to normalize EC responses in the diseased state. This Review focuses on PIK3CA's role in mediating EC responses to FSS and discusses current understanding of PIK3CA dysregulation in a range of vascular anomalies that particularly affect low-perfused regions of the vasculature. We also discuss recent surprising findings linking increased PI3K signaling to fast-flow arteriovenous malformations in hereditary hemorrhagic telangiectasias. [ABSTRACT FROM AUTHOR]

AbstractThe present paper focuses on the computational modeling of the unsteady non-Newtonian electro-magnetohydrodynamic flow of nano-blood through the inclined and tapered saturated porous artery with overlapping stenosis. The Carreau fluid model is adopted to simulate the non-Newtonian behavior of the blood. This study also uses a modified form of Darcy’s law applied to the Carreau model. Blood is doped with a suspension of homogeneous biocompatible nanoparticles of different shapes. In addition, a combination of a magnetic field and an electric field has also been taken into account. The significance of this work rests in the ability to enhance comprehension of the complicated behavior of hemodynamic flow when exposed to external fields and porous media with the addition of nanoparticles, which has substantial implications for the regulation and treatment of cardiovascular diseases. The finite-difference method is used to obtain the solution of the resulting equations. The simulations are applicable to targeted magnetic therapy for stenotic artery disease and the delivery of nanomedicines. [ABSTRACT FROM AUTHOR]