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End-stage kidney disease (ESKD) presents a significant public health challenge, with hemodialysis (HD) remaining one of the most prevalent kidney replacement therapies. Ensuring the longevity and functionality of arteriovenous accesses is challenging for HD patients. Blood flow sound, which contains valuable information, has often been neglected in the past. However, machine learning offers a new approach, leveraging data non-invasively and learning autonomously to match the experience of healthcare professionas. This study aimed to devise a model for detecting arteriovenous grafts (AVGs) stenosis. A smartphone stethoscope was used to record the sound of AVG blood flow at the arterial and venous sides, with each recording lasting one minute. The sound recordings were transformed into mel spectrograms, and a 14-layer convolutional neural network (CNN) was employed to detect stenosis. The CNN comprised six convolution blocks with 3x3 kernel mapping, batch normalization, and rectified linear unit activation function. We applied contrastive learning to train the pre-training audio neural networks model with unlabeled data through self-supervised learning, followed by fine-tuning. In total, 27,406 dialysis session blood flow sounds were documented, including 180 stenosis blood flow sounds. Our proposed framework demonstrated a significant improvement (p<0.05) over training from scratch and a popular pre-trained audio neural networks (PANNs) model, achieving an accuracy of 0.9279, precision of 0.8462, and recall of 0.8077, compared to previous values of 0.8649, 0.7391, and 0.6538. This study illustrates how contrastive learning with unlabeled blood flow sound data can enhance convolutional neural networks for detecting AVG stenosis in HD patients. [ABSTRACT FROM AUTHOR]

Objective: To investigate the diagnostic value of D-dimer, platelet-lymphocyte rate (PLR) and CT signs for intestinal ischemia in patients with bowel obstruction. Methods: We retrospectively analyzed the clinical and imaging data of 105 patients diagnosed with bowel obstruction, and performed univariate and multivariate analyses to determine the independent risk factors for intestinal ischemia in patients with bowel obstruction. Moreover, the receiver operating characteristic curve (ROC) was plotted to examine the diagnostic value of D-dimer, PLR and CT signs in patients with bowel obstruction. Besides, Kappa tests were used to assess inter-observer agreement. Results: We included 56 men (53%) and 49 women (47%) with mean age of 66.05 ± 16 years. Univariate and multivariate analyses showed that D-dimer, PLR and two significant CT signs (i.e., increased unenhanced bowel-wall attenuation and mesenteric haziness) were independent risk factors for intestinal ischemia in patients with bowel obstruction. ROC analysis showed that the combined use of D-dimer, PLR and the said two CT signs had better performance than single indicators in predicting intestinal ischemia in patients with bowel obstruction. The area under the curve (AUC) of the joint model III was 0.925 [95%CI: 0.876–0.975], with a sensitivity of 79.2% [95CI%: 67.2–91.1] and a specificity of 91.2% [95%CI: 83.7–98.9]. Conclusion: The combined use of D-dimer, PLR and CT signs has high diagnostic value for intestinal ischemia in patients with bowel obstruction and will prompt surgical exploration to evaluate intestinal blood flow. [ABSTRACT FROM AUTHOR]

The human forearm model is commonly employed in physiological investigations exploring local vascular function and oxygen delivery; however, the effect of arm dominance on exercising forearm hemodynamics and skeletal muscle oxygen saturation (SmO2) in untrained individuals is poorly understood. Therefore, the purpose of this study was to explore the effect of self-identified arm dominance on forearm hemodynamics and SmO2 in untrained individuals during submaximal, non-ischemic forearm exercise. Twenty healthy individuals (23±4 years, 50% female; 80% right-handed) completed three-minute bouts of supine rhythmic (1 second contraction: 2 second relaxation duty cycle) forearm handgrip exercise at both absolute (10kg; 98N) and relative (30% of maximal voluntary contraction) intensities in each forearm. Beat-by-beat measures of forearm blood flow (FBF; ml/min), mean arterial blood pressure (MAP; mmHg) and flexor digitorum superficialis SmO2 (%) were obtained throughout and averaged during the final 30 seconds of rest, exercise, and recovery while forearm vascular conductance was calculated (FVC; ml/min/100mmHg). Data are Δ from rest (mean±SD). Absolute force production did not differ between non-dominant and dominant arms (97±11 vs. 98±13 N, p = 0.606) whereas relative force production in females did (69±24 vs. 82±25 N, p = 0.001). At both exercise intensities, FBFRELAX, FVCRELAX, MAPRELAX, and the time constant tau for FBF and SmO2 were unaffected by arm dominance (all p>0.05). While arm dominance did not influence SmO2 during absolute intensity exercise (p = 0.506), the non-dominant arm in females experienced an attenuated reduction in SmO2 during relative intensity exercise (-14±10 vs. -19±8%, p = 0.026)–though exercise intensity was also reduced (p = 0.001). The present investigation has demonstrated that arm dominance in untrained individuals does not impact forearm hemodynamics or SmO2 during handgrip exercise. [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]

This study protocol aims to investigate how localised cooling influences the skin's microvascular, inflammatory, structural, and perceptual tolerance to sustained mechanical loading at the sacrum, evaluating factors such as morphology, physiology, and perceptual responses. The protocol will be tested on individuals of different age, sex, skin tone and clinical status, using a repeated-measure design with three participants cohorts: i) young healthy (n = 35); ii) older healthy (n = 35); iii) spinal cord injured (SCI, n = 35). Participants will complete three testing sessions during which their sacrum will be mechanically loaded (60 mmHg; 45 min) and unloaded (20 min) with a custom-built thermal probe, causing pressure-induced ischemia and post-occlusive reactive hyperaemia. Testing sessions will differ by the probe's temperature, which will be set to either 38°C (no cooling), 24°C (mild cooling), or 16°C (strong cooling). We will measure skin blood flow (via Laser Doppler Flowmetry; 40 Hz); pro- and anti-inflammatory biomarkers in skin sebum (Sebutape); structural skin properties (Optical Coherence Tomography); and ratings of thermal sensation, comfort, and acceptance (Likert Scales); throughout the loading and unloading phases. Changes in post-occlusive reactive hyperaemia will be considered as the primary outcome and data will be analysed for the independent and interactive effects of stimuli's temperature and of participant group on within- and between-subject mean differences (and 95% Confidence Intervals) in peak hyperaemia, by means of a 2-way mixed model ANOVA (or Friedman). Regression models will also be developed to assess the relationship between absolute cooling temperatures and peak hyperaemia. Secondary outcomes will be within- and between-subject mean changes in biomarkers' expression, skin structural and perceptual responses. This analysis will help identifying physiological and perceptual thresholds for the protective effects of cooling from mechanically induced damage underlying the development of pressure ulcers in individuals varying in age and clinical status. [ABSTRACT FROM AUTHOR]

Ovarian torsion (OT) is a gynecological emergency that can have diverse clinical presentations makings its diagnosis especially challenging. Few studies exist in the literature describing the clinical presentation as well as the management of OT in the emergency department (ED). This study aims to describe the clinical presentation, physical examination, emergency management, radiographic and intraoperative findings, histopathology reports and the time-to-intervention metrics of OT cases presenting to the emergency room of our tertiary care center. Data was collected by a retrospective chart review of all OT cases that presented to our ED over a period of 1 year. A total of 20 cases were included in the final analysis. The incidence of OT in the ED was 157.4 per 100 000 visits of women in the reproductive age group. All patients were women of reproductive age, with a mean age of 27.3 years. A total of 15 patients (78.9%) presented within 24 hours of symptom onset. The most common presenting symptom was abdominal pain (95%, 19/20) with most localizing to the right lower quadrant (60%, 12/20), followed by nausea and vomiting (90%, 18/20). Almost all patients (95%, 19/20) required opioids for pain management. The majority (80%, 16/20) were diagnosed by ultrasound prior to surgery, whereas (20%, 4/20) went straight to surgery based on a high index of clinical suspicion. Among those who underwent ultrasound, ovarian cyst was present in (75%, 12/16) while (68.9%, 11/16) showed ovarian enlargement and (50%, 8/16) showed abnormal ovarian blood flow. All patients except one patient underwent operative management. Out of the 19 patients who underwent surgery, the majority of patients (94.7%, 18/19) had viable ovaries with the exception of 1 patient (5.3%) who required a salpingo-oophorectomy post ovarian detorsion. A total of 13 cases included histopathologic review of specimens out of which 6 (46.2%) had a mature cystic teratoma. The mean time from door to ultrasonography was 1.4 hours and from door to surgery was 11.4 hours. Our study provides valuable insights into the incidence, clinical presentation, physical examination, emergency management, ultrasonographic and intraoperative findings, histopathology reports as well as the time-to-intervention metrics of OT patients presenting to the ED. [ABSTRACT FROM AUTHOR]

Background: Recently, we developed a chest compression device that can move the chest compression position without interruption during CPR and be remotely controlled to minimize rescuer exposure to infectious diseases. The purpose of this study was to compare its performance with conventional mechanical CPR device in a mannequin and a swine model of cardiac arrest. Materials and methods: A prototype of a remote-controlled automatic chest compression device (ROSCER) that can change the chest compression position without interruption during CPR was developed, and its performance was compared with LUCAS 3 in a mannequin and a swine model of cardiac arrest. In a swine model of cardiac arrest, 16 male pigs were randomly assigned into the two groups, ROSCER CPR (n = 8) and LUCAS 3 CPR (n = 8), respectively. During 5 minutes of CPR, hemodynamic parameters including aortic pressure, right atrial pressure, coronary perfusion pressure, common carotid blood flow, and end-tidal carbon dioxide partial pressure were measured. Results: In the compression performance test using a mannequin, compression depth, compression time, decompression time, and plateau time were almost equal between ROSCER and LUCAS 3. In a swine model of cardiac arrest, coronary perfusion pressure showed no difference between the two groups (p = 0.409). Systolic aortic pressure and carotid blood flow were higher in the LUCAS 3 group than in the ROSCER group during 5 minutes of CPR (p < 0.001, p = 0.008, respectively). End-tidal CO2 level of the ROSCER group was initially lower than that of the LUCAS 3 group, but was higher over time (p = 0.022). A Kaplan-Meier survival analysis for ROSC also showed no difference between the two groups (p = 0.46). Conclusion: The prototype of a remote-controlled automated chest compression device can move the chest compression position without interruption during CPR. In a mannequin and a swine model of cardiac arrest, the device showed no inferior performance to a conventional mechanical CPR device. [ABSTRACT FROM AUTHOR]

A liquid-based perinatal life support system (PLS) for extremely premature infants (born before 28 week of gestational age) envisions a connection between the infant's native umbilical cord and an artificial placenta system through cannulation. This system mimics a natural mothers' womb to achieve better organ maturations. The objective of this study is to gain insight into the clinical focus points of umbilical cord cannulation and how cannulation should be addressed in extremely premature infants during the transfer from the uterus to an in-utero simulating liquid-based PLS system. We performed an explorative qualitative study. Twelve medical specialists with knowledge of vessel cannulation participated. We collected data through twelve interviews and two focus group discussions. Data were analyzed using inductive content and constant comparison analysis via open and axial coding. Results were derived on the following topics: (1) cannulation technique, (2) cannula fixation, (3) local and systemic anticoagulation, and (4) vasospasm. A side-entry technique is preferred as this may decrease wall damage, stabilizes the vessel better and ensures continuous blood flow. Sutures, especially via an automatic microsurgery instrument, are favored above glue, stents, or balloons as these may be firmer and faster. Medication possibilities for both vasospasm and anticoagulation should function locally since there were uncertainties regarding the systemic effects. According to the findings of this research, the needed umbilical cord cannulation method should include minimal wall damage, improved vascular stability, blood flow maintenance, a strong fixation connection, and local anticoagulation effect. [ABSTRACT FROM AUTHOR]

Low-intensity endurance exercise with blood flow restriction (KAATSU) is under consideration for use in cardiac rehabilitation. However, the physiological responses to such exercise have not yet been fully characterized. In an initial effort in healthy males (n = 11, age: 26.3±4.6 y), we compared the physiological responses to low-intensity endurance exercise with and without a thigh KAATSU. Participants performed maximal graded exercise testing using a cycle ergometer with or without KAATSU. We examined responses to cycling exercise at ventilatory threshold (VT) in heart rate (HR), oxygen consumption (VO2), dyspnea, ratings of perceived exertion (RPE), blood pressure (BP), and rectus femoris activation. Participants reached VT at a lower mechanical load, HR, VO2, dyspnea, and double product (HR×systolic BP) with KAATSU vs. no-KAATSU. At VT, RPE, and rectus femoris activity did not differ between the two conditions. These results suggest that KAATSU reduced exercise intensity to reach VT and the physiological responses to exercise at VT without changes in knee extensor muscle activation. Results from this pilot study in healthy males suggest that KAATSU aerobic exercise at VT intensity has the potential to be an effective and low-burden adjuvant to cycling in cardiac rehabilitation. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the effect of a 1% brinzolamide and 0.1% brimonidine fixed combination (BBFC) on ONH blood flow (BF) in rabbits. Methods: A crossover study was conducted on pigmented rabbits; a physiological saline solution, brinzolamide, or BBFC was administered for eight days. ONH BF, intraocular pressure (IOP) and systemic parameters were measured before the eighth day's first dose and at 6, 9, 12, and 14 hours after the dose. ONH BF was assessed using laser speckle flowgraphy, and mean blur rate (MBR) values were calculated. The percentage against baseline of each parameter was calculated, and intergroup comparisons were performed at each time point. Results: There were no significant differences in the percentage change in systemic parameters. At 6 hours after administration, the BBFC group showed a significantly higher percentage change in large vessel area-MBR (%MV) compared to the control group (98.6±16.8%MV vs. 81.3±7.9%MV, P = 0.03). On the other hand, the brinzolamide group did not show a significant difference. Both the brinzolamide and BBFC groups had significantly lower percentage change in IOP (%IOP) compared to the control group (90.6±5.0%IOP, 93.3±2.9%IOP, and 99.2±1.7%IOP, respectively, P < 0.01). Conclusion: BBFC effectively reduces IOP and mitigates diurnal fluctuation-induced decreases in ONH BF. [ABSTRACT FROM AUTHOR]

The heart is widely acknowledged as the unique driver of blood circulation. Recently, we discovered a flow-driving mechanism that can operate without imposed pressure, using infrared (IR) energy to propel flow. We considered the possibility that, by exploiting this mechanism, blood vessels, themselves, could propel flow. We verified the existence of this driving mechanism by using a three-day-old chick-embryo model. When the heart was stopped, blood continued to flow for approximately 50 minutes, albeit at a lower velocity. When IR was introduced, the postmortem flow increased from ~41.1 ± 25.6 μm/s to ~153.0 ± 59.5 μm/s (n = 6). When IR energy was diminished under otherwise physiological conditions, blood failed to flow. Hence, this IR-dependent, vessel-based flow-driving mechanism may indeed operate in the circulatory system, complementing the action of the heart. [ABSTRACT FROM AUTHOR]

Shame can be defined as the emotional response to one's violations of rules being exposed to others. However, it is difficult to objectively measure this concept. This study examined the psychophysiological indicators of shame in young children using behavioral methods and thermography, which measures facial temperatures that reflect blood flow changes related to emotions. Four- to six-year-old children participated in an "animal guessing game," in which they lied about having violated a rule. They were assigned to either the exposure or the non-exposure group. In the exposure group, participants' lies were exposed by the experimenter, whereas in the non-exposure group, their lies were not. Results showed that at the behavioral level, participants in the exposure group expressed characteristic behaviors of shame (e.g., embarrassed smiles) more often than those in the non-exposure group. Moreover, the nasal temperatures of participants in the exposure group were higher than those of participants in the other group after the lie was exposed. These results suggest that participants' lies being exposed induced psychophysiological responses and consequently raised their nasal temperature. This finding indicates that psychophysiological responses can enable us to objectively measure higher-order emotions in young children. [ABSTRACT FROM AUTHOR]

Background: Left-sided breast cancer patients receiving adjuvant radiotherapy are at risk for coronary artery disease, and/or radiation mediated effects on the microvasculature. Previously our laboratory demonstrated in canines with hybrid 18FDG/PET a progressive global inflammatory response during the initial one year following treatment. In this study, the objective is to evaluate corresponding changes in perfusion, in the same cohort, where resting myocardial blood flow (MBF) was quantitatively measured. Method: In five canines, Ammonia PET (13NH3) derived MBF was measured at baseline, 1-week, 1, 3, 6 and 12-months after cardiac external beam irradiation. MBF measurements were correlated with concurrent 18FDG uptake. Simultaneously MBF was measured using the dual bolus MRI method. Results: MBF was significantly increased at all time points, in comparison to baseline, except at 3-months. This was seen globally throughout the entire myocardium independent of the coronary artery territories. MBF showed a modest significant correlation with 18FDG activity for the entire myocardium (r = 0.51, p = 0.005) including the LAD (r = 0.49, p = 0.008) and LCX (r = 0.47, p = 0.013) coronary artery territories. Conclusion: In this canine model of radiotherapy for left-sided breast cancer, resting MBF increases as early as 1-week and persists for up to one year except at 3-months. This pattern is similar to that of 18FDG uptake. A possible interpretation is that the increase in resting MBF is a response to myocardial inflammation. [ABSTRACT FROM AUTHOR]

Objectives: The present paper aims to characterize the Angiotensin-converting enzyme (ACE) genotype, with particular emphasis on its association with arterial oxygen saturation, arterial blood pressure, hemoglobin [Hb] concentration, and ventilatory measures among the Tawang Monpa, a high-altitude native population of the Eastern Himalaya, India. Methods: A cross-sectional sample of 168Monpa participants from Tawang town, Arunachal Pradesh, India, was selected who live at an altitude of ∼3,200 meters (m) above sea level. For each participant, height, weight, and skinfold thickness were measured, based on which body mass index (BMI, kg/m2) and percentage of body fat (%BF) were calculated. Physiological measures, such as the transcutaneous arterial oxygen saturation (SaO2), hemoglobin [Hb] concentration, forced vital capacity (FVC), forced expiratory volume in 1-second (FEV1), and systemic arterial blood pressure were measured. First, the peripheral venous blood samples (four ml) were drawn, and then white blood cells were separated for the ACE genotyping of each participant. Results: Unlike high-altitude natives from Peru and Ladakh, who exhibit high frequencies of II homozygotes, the Tawang Monpa shows a significantly high frequency of ID heterozygotes (p<0.0001). In addition, no significant association was identified between ACE gene polymorphism and arterial blood pressure, oxygen saturation at rest, vital capacity, or [Hb] concentration. Discussion: The results suggest that the association of the ACE gene with resting SaO2 is inconsistent across native populations living under hypobaric hypoxia. Further, ACE I/D gene polymorphism may not be under natural selection in specific native populations, including Tawang Monpa, for their adaptation to high-altitude hypoxia. [ABSTRACT FROM AUTHOR]

Purpose: To examine whether extended interscan time (IST) on optical coherence tomography angiography (OCTA) can detect slow retinal blood flow, which is undetectable on default IST, in the healthy macula. Methods: OCTA (OCT-A1, Canon Inc.) scanning of a macular area measuring 4 × 4 mm2 of 14 healthy eyes of 14 healthy volunteers with no history or evidence of systemic and macular diseases was performed. ISTs were set at 7.6 (IST7.6, default setting), 12.0 (IST12.0), and 20.6 msec (IST20.6). Ten OCTA images were acquired at each IST, and an averaged image was created. For each averaged OCTA image obtained at IST7.6, IST12.0, and IST20.6, we defined the area surrounded by the innermost capillary ring as the foveal avascular zone (FAZ). We qualitatively evaluated the delineation of the capillaries consisting of the FAZ and quantitatively measured the FAZ area at each IST. Results: Extensions from IST7.6 to IST12.0 and IST20.6 could newly delineated retinal capillaries that were undetectable at the default IST; new capillaries were detected in 10 (71%) eyes at IST12.0 and 11 (78%) eyes at IST20.0. The FAZ areas were 0.334 ± 0.137 mm2, 0.320 ± 0.132 mm2, and 0.319 ± 0.129 mm2 for IST7.6, IST12.0, and IST20.0, respectively; the FAZ areas at IST12.0 and IST20.0 were significantly decreased compared with that at IST7.6 (p = 0.004 and 0.002, respectively). Conclusion: In OCTA for healthy participants, extensions of the ISTs newly detected retinal capillaries with slow blood flow around FAZ. The FAZ shapes varied with different ISTs. Thus, the blood flow dynamics are not physiologically uniform around FAZ. Compared with conventional OCTA, this protocol enables a more detailed evaluation of retinal circulation and provides a better understanding of the physiological circulatory status of the healthy retina, and may enable the assessment of circulation in the very early stages in diseased eyes. [ABSTRACT FROM AUTHOR]

Models of arterial injury in rodents have been invaluable to our current understanding of vessel restenosis and play a continuing role in the development of endovascular interventions for cardiovascular disease. Mechanical distention of the vessel wall and denudation of the vessel endothelium are the two major modes of vessel injury observed in most clinical pathologies and are critical to the reproducible modelling of progressive neointimal hyperplasia. The current models which have dominated this research area are the mouse wire carotid or femoral injury and the rat carotid balloon injury. While these elicit simultaneous distension of the vessel wall and denudation of the luminal endothelium, each model carries limitations that need to be addressed using a complementary injury model. Wire injuries in mice are highly technical and procedurally challenging due to small vessel diameters, while rat balloon injuries require permanent blood vessel ligation and disruption of native blood flow. Complementary models of vascular injury with reproducibility, convenience, and increased physiological relevance to the pathophysiology of endovascular injury would allow for improved studies of neointimal hyperplasia in both basic and translational research. In this study, we developed a new surgical model that elicits vessel distention and endothelial denudation injury using sequential steps using microforceps and a standard needle catheter inserted via arteriotomy into a rat common carotid artery, without requiring permanent ligation of branching arteries. After 2 weeks post-injury this model elicits highly reproducible neointimal hyperplasia and rates of re-endothelialisation similar to current wire and balloon injury models. Furthermore, evaluation of the smooth muscle cell phenotype profile, inflammatory response and extracellular matrix within the developing neointima, showed that our model replicated the vessel remodelling outcomes critical to restenosis and those becoming increasingly focused upon in the development of new anti-restenosis therapies. [ABSTRACT FROM AUTHOR]

Elevations of plasma creatinine are common after major surgery, but their pathophysiology is poorly understood. To identify possible contributing mechanisms, we pooled data from eight prospective studies performed in four different countries to study circumstances during which elevation of plasma creatinine occurs. We included 642 patients undergoing mixed major surgeries, mostly open gastrointestinal. Plasma and urinary creatinine and a composite index for renal fluid conservation (Fluid Retention Index, FRI) were measured just before surgery and on the first postoperative morning. Urine flow was measured during the surgery. The results show that patients with a postoperative increase in plasma creatinine by >25% had a high urinary creatinine concentration (11.0±5.9 vs. 8.3±5.6 mmol/L; P< 0001) and higher FRI value (3.2±1.0 vs. 2.9±1.1; P< 0.04) already before surgery was initiated. Progressive increase of plasma creatinine was associated with a gradually lower urine flow and larger blood loss during the surgery (Kruskal-Wallis test, P< 0.001). The patients with an elevation > 25% also showed higher creatinine and a higher FRI value on the first postoperative morning (P< 0.001). Elevations to > 50% of baseline were associated with slightly lower mean arterial pressure (73 ± 10 vs. 80 ± 12 mmHg; P< 0.005). We conclude that elevation of plasma creatinine in the perioperative period was associated with low urine flow and greater blood loss during surgery and with concentrated urine both before and after the surgery. Renal water conservation-related mechanisms seem to contribute to the development of increased plasma creatinine after surgery. [ABSTRACT FROM AUTHOR]

Background: Automatic chest compression devices (ACCDs) can promote high-quality cardiopulmonary resuscitation (CPR) and are widely used worldwide. Early application of automated external defibrillators (AEDs) along with high-quality CPR is crucial for favorable outcomes in patients with cardiac arrest. Here, we developed an automated CPR (A-CPR) apparatus that combines ACCD and AED and evaluated its performance in a pilot animal-based study. Methods: Eleven pigs (n = 5, A-CPR group; n = 6, ACCD CPR and AED [conventional CPR (C-CPR)] group) were enrolled in this study. After 2 min observation without any treatment following ventricular fibrillation induction, CPR with a 30:2 compression/ventilation ratio was performed for 6 min, mimicking basic life support (BLS). A-CPR or C-CPR was applied immediately after BLS, and resuscitation including chest compression and defibrillation, was performed following a voice prompt from the A-CPR device or AED. Hemodynamic parameters, including aortic pressure, right atrial pressure, coronary perfusion pressure, carotid blood flow, and end-tidal carbon dioxide, were monitored during resuscitation. Time variables, including time to start rhythm analysis, time to charge, time to defibrillate, and time to subsequent chest compression, were also measured. Results: There were no differences in baseline characteristics, except for arterial carbon dioxide pressure (39 in A-CPR vs. 33 in C-CPR, p = 0.034), between the two groups. There were no differences in hemodynamic parameters between the groups. However, time to charge (28.9 ± 5.6 s, A-CPR group; 47.2 ± 12.4 s, C-CPR group), time to defibrillate (29.1 ± 7.2 s, A-CPR group; 50.5 ± 12.3 s, C-CPR group), and time to subsequent chest compression (32.4 ± 6.3 s, A-CPR group; 56.3 ± 10.7 s, C-CPR group) were shorter in the A-CPR group than in the C-CPR group (p = 0.015, 0.034 and 0.02 respectively). Conclusions: A-CPR can provide effective chest compressions and defibrillation, thereby shortening the time required for defibrillation. [ABSTRACT FROM AUTHOR]

Duplex ultrasound (DUS) is the most widely used method for surveillance of arteriovenous fistulae (AVF) created for dialysis. However, DUS is poor at predicting AVF outcomes and there is a need for novel methods that can more accurately evaluate multidirectional AVF flow. In this study we aimed to evaluate the feasibility of detecting AVF stenosis using a novel method combining tensor-decomposition of B-mode ultrasound cine loops (videos) of blood flow and machine learning classification. Classification of stenosis was based on the DUS assessment of blood flow volume, vessel diameter size, flow velocity, and spectral waveform features. Real-time B-mode cine loops of the arterial inflow, anastomosis, and venous outflow of the AVFs were analysed. Tensor decompositions were computed from both the 'full-frame' (whole-image) videos and 'cropped' videos (to include areas of blood flow only). The resulting output were labelled for the presence of stenosis, as per the DUS findings, and used as a set of features for classification using a Long Short-Term Memory (LSTM) neural network. A total of 61 out of 66 available videos were used for analysis. The whole-image classifier failed to beat random guessing, achieving a mean area under the receiver operating characteristics (AUROC) value of 0.49 (CI 0.48 to 0.50). In contrast, the 'cropped' video classifier performed better with a mean AUROC of 0.82 (CI 0.66 to 0.96), showing promising predictive power despite the small size of the dataset. The combined application of tensor decomposition and machine learning are promising for the detection of AVF stenosis and warrant further investigation. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare choroidal adjusted flow index (AFI) in healthy, hypertensive & preeclamptic pregnancies using optical coherence tomography angiography (OCTA). Methods: In this prospective study, healthy, hypertensive & preeclamptic third trimester pregnant women underwent OCTA imaging. 3x3 & 6x6 mm choriocapillaris slabs were exported and the parafoveal area was marked by two concentric ETDRS circles at 1 & 3 mm, centered on the foveal avascular zone. Parafoveal AFI was calculated as a parameter of choroidal blood flow. Results: Fifteen eyes of fifteen women per group were recruited (45 eyes). AFI was significantly lower in the preeclamptic compared to the healthy & hypertensive groups (Tukey HSD: <0.001 in both groups on 3x3 mm, and 0.02 & 0.04 in 6x6 mm scans), and in the hypertensive compared to the healthy group (0.005 & 0.03 in 3x3 & 6x6 mm scans respectively). Conclusions: Pregnancies complicated with preeclampsia revealed the lowest choroidal blood flow on OCTA followed by pregnancies with systemic hypertension compared to healthy pregnancies. We provide in-vivo documentation of choroidal ischemia, highlighting its culpability in hypertensive and preeclamptic retinochoroidal pathology, and the possibility of utilizing choroidal blood flow on OCTA as a precursor for disease progression. [ABSTRACT FROM AUTHOR]

Background: Healthcare simulators have been demonstrated to be a valuable resource for training several technical and nontechnical skills. A gap in the fidelity of tissues has been acknowledged as a barrier to application for current simulators; especially for interventional procedures. Inaccurate or unrealistic mechanical response of a simulated tissue to a given surgical tool motion may result in negative training transfer and/or prevents the "suspension of disbelief" necessary for a trainee to engage in the activity. Thus, where it is relevant to training outcomes, there should be an effort to create healthcare simulators with simulated tissue mechanical responses that match or represent those of biological tissues. Historically, this data is most often gathered from preserved (post mortem) tissue; however, there is a concern that the mechanical properties of preserved tissue, that lacks blood flow, may lack adequate accuracy to provide the necessary training efficacy of simulators. Methods and findings: This work explores the effect of the "state" of the tissue testing status on liver and peritoneal tissue by using a customized handheld grasper to measure the mechanical responses of representative porcine (Sus domesticus) tissues in n = 5 animals across five test conditions: in vivo, post mortem (in-situ), ex vivo (immediately removed from fresh porcine cadaver), post-refrigeration, and post-freeze-thaw cycle spanning up to 72 hours after death. No statistically significant difference was observed in the mechanical responses due to grasping between in vivo and post-freeze conditions for porcine liver and peritoneum tissue samples (p = 0.05 for derived stiffness at grasping force values F = 5N and 6.5N). Furthermore, variance between in vivo and post-freeze conditions within each animal, was comparable to the variance of the in vivo condition between animals. Conclusions: Results of this study further validate the use of preserved tissue in the design of medical simulators via observing tissue mechanical responses of post-freeze tissue comparable to in vivo tissue. Therefore, the use of thawed preserved tissue for the further study and emulation of mechanical perturbation of the liver and peritoneum can be considered. Further work in this area should investigate these trends further, particularly in regard to other tissues and the potential effects varying preservation methods may yield. [ABSTRACT FROM AUTHOR]

This cross-sectional study compared optical coherence tomography angiography (OCTA) parameters between older Black and White adults with systemic comorbidities in an effort to further understand racial differences in the retinal microvasculature. We analyzed vessel density at the superficial (SCP), intermediate (ICP), and deep capillary plexuses (DCP), foveal avascular zone (FAZ) parameters, and blood flow area (BFA) at the choriocapillaris. We used a mixed-effects linear regression model, controlling for hypertension and two eyes from the same subject, to compare OCTA parameters. Black subjects had lower foveal vessel density at the SCP and ICP, while no differences were observed at the parafovea or 3x3 mm macular area of any capillary layer. Black subjects had greater FAZ area, perimeter, and FD-300, a measurement of vessel density in a 300 μm wide ring around the FAZ. Black subjects also had lower BFA at the choriocapillaris. Within a cohort of subjects without hypertension, these differences remained statistically significant, with the exception of foveal vessel density at the SCP and foveal BFA of the choriocapillaris. These findings suggest that normative databases of OCTA parameters must strive to be diverse in nature to adequately capture differences across patient populations. Further study is required to understand if baseline differences in OCTA parameters contribute to epidemiological disparities in ocular diseases. [ABSTRACT FROM AUTHOR]

Laser therapeutic applications, such as the use of high energy lasers (HILT), are widely used in physical therapy, but basic studies on the mechanisms of action of HILT on tendinous/ligamentous tissue are largely lacking. The aim of this study was to investigate microcirculatory changes of the patellar tendon by HILT. 21 healthy volunteers were included in the present investigation. Before and after HILT, as well as 10 minutes later, the microcirculation was measured by noninvasive laser Doppler and white light spectroscopy (O2C device). Tissue temperature was recorded at the measurement time points using thermography. Blood flow increased significantly by 86.38 arbitrary units (AU; p < 0.001) after the intervention and by 25.76 AU (p < 0.001) at follow-up. Oxygen saturation increased by 20.14% (p < 0.001) and 13.48%, respectively (p < 0.001), whereas relative hemoglobin decreased by 6.67 AU and 7.90 AU, respectively. Tendon temperature increased by 9.45° and 1.94° Celsius, respectively. Acceleration of blood flow by improving the flow properties of erythrocytes and platelets may have caused the results. HILT could be a therapeutic perspective for tendon pathologies with impaired microcirculation, although further studies are needed to validate the experimental results. [ABSTRACT FROM AUTHOR]

Purpose: To determine the blood flow pattern of eyes before the development of type 3 macular neovascularization (MNV) by optical coherence tomography angiography (OCTA). Study design: Retrospective study. Subjects: Ten eyes of 10 patients (4 men and 6 women, mean age 80.4 years) diagnosed with unilateral Type 3 MNV who developed type 3 MNV in the fellow normal eye during the follow-up period were studied. Methods: The time of onset of type 3 MNV was defined as the time when retinal exudation was detected by OCT. The blood flow of a 3 x 3 mm or 6 x 6 mm area in the deep capillary plexus (DCP) and the outer retina (OR) including the central fovea were assessed at the onset and at 6 months prior to the onset of the type 3 MNV. Results: All MNVs that developed in the fellow eye were type 3 MNVs. Abnormal blood flow signals in the MNVs were detected in the DCP and/or the OR by OCTA at the onset in all cases. Eight of the 10 eyes had OCTA recordings prior to the development of the MNV: 3 eyes had non-exudative MNVs only in the DCP and 5 eyes had non-exudative MNVs in the DCP and OR. The exudation appeared on the average 3.5 months after the non-exudative MNV was observed in the fellow eyes. Conclusions: A non-exudative MNV in the fellow eyes can already be observed by OCTA in eyes before the onset of the exudation. Knowing this will help clinicians not only how to treat these eyes appropriately but will also help in determining the origin of the MNV. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the association of systemic oxidative stress markers and optic nerve head (ONH) blood flow in normal-tension glaucoma (NTG) patients, as well as sex differences in this association. Methods: This was a cross-sectional study of 235 eyes with NTG of 134 patients (56 male, 78 female; mean age, 60.9±14.1 years). Laser speckle flowgraphy (LSFG) was used to measure ONH blood flow (mean blur rate in the tissue area of the ONH; MBR-T) and LSFG pulse-waveform parameters, including flow acceleration index in the tissue area of the ONH (FAI-T). Oxidative stress markers, diacron-reactive oxygen metabolites (d-ROMs), and biological antioxidant potential (BAP) were measured with a free radical elective evaluator. Spearman's rank correlation test and a multivariate linear mixed-effect model were used to investigate factors associated with ONH blood flow. Results: MBR-T was significantly correlated with age (rs = -0.28, p < 0.001), mean arterial pressure (rs = -0.20, p = 0.002), intraocular pressure (rs = 0.24, p < 0.001), peripapillary retinal nerve fiber layer thickness (rs = 0.62, p < 0.001), and disc area (rs = -0.26, p < 0.001), but not with serum d-ROM level. Separate analyses of the subjects divided by sex showed that BAP was positively correlated to MBR-T (rs = 0.21, p = 0.036) and FAI-T (rs = 0.36, p < 0.001) only in male subjects. Similarly, BAP was significantly associated with MBR-T (β = 0.25, p = 0.026) and FAI-T (β = 0.37, p < 0.001) in male subjects in a multivariate linear mixed-effect model. Conclusion: A lower serum antioxidant level, as indicated by BAP, was associated with reduced ONH blood flow only in male NTG patients. Our findings suggest that there are sex differences in the involvement of oxidative stress in the pathogenesis of reduced ocular blood flow in NTG. [ABSTRACT FROM AUTHOR]

This paper presents a numerical analysis of blood flow in a diseased vessel within the presence of an external magnetic field. The blood flow was considered to be incompressible and fully developed, in that the non-Newtonian nature of the fluid was characterised as a generalised power law model for shear-thinning, Newtonian, and shear-thickening fluids. The impact of a transverse directed external magnetic field on blood flow through a stenosed bifurcated artery was investigated. The arterial geometry was considered as a bifurcated channel with overlapping shaped stenosis. The problem was treated mathematically using the Galerkin Least-Squares (GLS) method. The implementation of this numerical method managed to overcome the numerical instability faced by the classical Galerkin technique when adopted to a highly viscous flow. The benefit of GLS in circumventing the Ladyzhenskaya-Babuška-Brezzi (LBB) condition was utilized by evaluating both the velocity and pressure components at corner nodes of a unstructured triangular element. The non-linearity that emerged from the convective terms was then treated using the Newton-Raphson method, while the numerical integrals were computed using a Gaussian quadrature rule with six quadrature points. The findings obtained from this study were then compared with available results from the literature as well as Comsol multiphysics software to verify the accuracy and validity of the numerical algorithms. It was found that the application of magnetic field was able to overcome flow reversal by 39% for a shear-thinning fluid, 26% for a Newtonian fluid, and 27% for a shear-thickening fluid. The negative pressure and steep wall shear stress which occurs at the extremities of an overlapping stenosis throat were diminished by rise in magnetic intensity. This prevented thrombosis occurrence and produced a uniform calm flow. [ABSTRACT FROM AUTHOR]

Introduction: The newly introduced Cellular Oxygen METabolism (COMET®) monitor enables the measurement of mitochondrial oxygen tension (mitoPO2) using the protoporphyrin IX triplet state lifetime technique (PpIX-TSLT). This study aims to investigate the feasibility and applicability of the COMET® measurements in the operating theatre and study the behavior of the new parameter mitoPO2 during stable operating conditions. Methods: In this observational study mitochondrial oxygenation was measured in 20 patients during neurosurgical procedures using the COMET® device. Tissue oxygenation and local blood flow were measured by the Oxygen to See (O2C). Primary outcomes included mitoPO2, skin temperature, mean arterial blood pressure, local blood flow and tissue oxygenation. Results: All patients remained hemodynamically stable during surgery. Mean baseline mitoPO2 was 60 ± 19 mmHg (mean ± SD) and mean mitoPO2 remained between 40–60 mmHg during surgery, but tended to decrease over time in line with increasing skin temperature. Conclusion: This study presents the feasibility of mitochondrial oxygenation measurements as measured by the COMET® monitor in the operating theatre and shows the parameter mitoPO2 to behave in a stable and predictable way in the absence of notable hemodynamic alterations. The results provide a solid base for further research into the added value of mitochondrial oxygenation measurements in the perioperative trajectory. [ABSTRACT FROM AUTHOR]

Short bouts of occlusion of blood flow can induce a preconditioning response that reduces subsequent damage from longer periods of ischemia. It has been shown that ischemic preconditioning (IPC) can be elicited remotely (RIPC) through limitation of blood flow and as recently described via only pain sensation. Non-obstructive banding (NOB) through the donning of tefillin (a box with sacred texts attached to a leather strap that is traditionally bound to the non-dominant arm of Jewish adults during morning prayers) has been shown to elicit an RIPC response at least partially through pain sensation. This study evaluated the effects of NOB on heart rate variability (HRV) dependent factors that are known to be affected by various RIPC stimuli. We recruited 30 healthy subjects and subjected them to NOB versus control and found various HRV markers associated with RIPC to be changed in the NOB group. This finding provides further evidence that tefillin, likely through NOB induced RIPC changes, may still be a viable clinical pathway to prevent and decrease the morbidity associated with ischemic events. [ABSTRACT FROM AUTHOR]

This study assessed the acute effect of adding blood flow restriction (BFR) to quad sets on muscle-cross sectional area (mCSA), muscle thickness (MT), echo intensity (EI), and subcutaneous fat-normalized EI (EINORM) of the superficial quadriceps muscles. Twelve males and 12 females (mean±SD; age (yrs): 21.4±2.9; stature (m): 1.76±0.1; body mass (kg): 77.7±2.9) performed 70 repetitions (one set of 30, three sets of 15 repetitions) of bodyweight quad sets separately on each leg, with or without BFR (CON) applied. Rating of perceived exertion was recorded following each set. Panoramic ultrasound images of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) were captured prior to (PRE), immediately after (IMM-POST), 30- (30-POST), and 60-minutes after (60-POST) after exercise. Sex x condition x time repeated measures ANOVAs assessed differences at p<0.05 for each muscle and dependent variable separately. Although males had larger VM and VL mCSA and VL MT (p<0.05), there were no acute changes from PRE to IMM-POST (p>0.05). There was a 3-way interaction in VL mCSA (p = 0.025) which indicated BFR was greater than CON at IMM-POST by 7.6% (p = 0.019) for males only. Females had greater EI in the VM and VL than males (p<0.05), yet males had greater EINORM for each muscle (p>0.05) and EINORM did not change over time or treatment (p>0.05). The lack of changes in MT, EI, and EINORM indicate that unloaded quad sets do not provide a stimulus to promote fluid shifts or acute changes in muscle size with the exception of IMM-POST in the VL for males. Future research should attempt to elucidate the acute muscular responses of BFR application for lightly loaded rehabilitation exercises in the clinical populations for which they are prescribed. [ABSTRACT FROM AUTHOR]

Pulsatile arterial blood flow plays an important role in vascular system mechanobiology, especially in the study of mechanisms of pathology. Limitations in cost, time, sample size, and control across current in-vitro and in-vivo methods limit future exploration of novel treatments. Presented is the verification of a novel reciprocating positive displacement pump aimed at resolving these issues through the simulation of human ocular, human fingertip and skin surface, human cerebral, and rodent spleen organ systems. A range of pulsatile amplitudes, frequencies, and flow rates were simulated using pumps made of 3D printed parts incorporating a tubing system, check valve and proprietary software. Volumetric analysis of 430 total readings across a flow range of 0.025ml/min to 16ml/min determined that the pump had a mean absolute error and mean relative error of 0.041 ml/min and 1.385%, respectively. Linear regression analysis compared to expected flow rate across the full flow range yielded an R2 of 0.9996. Waveform analysis indicated that the pump could recreate accurate beat frequency for flow ranges above 0.06ml/min at 70BPM. The verification of accurate pump output opens avenues for the development of novel long-term in-vitro benchtop models capable of looking at fluid flow scenarios previously unfeasible, including low volume-high shear rate pulsatile flow. [ABSTRACT FROM AUTHOR]

Background: Obstructive sleep apnea (OSA) has been associated with incidence of cardiovascular disease and with nocturnal angina, but evidence of a link with coronary atherosclerosis and myocardial ischemia is limited and previous studies may have been affected by selection bias or unmeasured confounding factors. Methods: We performed overnight polysomnography in 178 older male twins. The Apnea/Hypopnea Index (AHI) was calculated to assess OSA from the overnight sleep evaluation. AHI ≥15 was used as indicator of moderate/severe OSA. The following day, twins underwent myocardial perfusion imaging with [82Rb]-chloride positron emission tomography. Quantitative and semiquantitative measures of myocardial perfusion and absolute myocardial blood flow were obtained. Results: The mean age was 68 years and 40% of the sample had an AHI≥15, which indicates moderate to severe OSA. Abnormal myocardial perfusion, both with stress and at rest, was more common in twins with elevated AHI. After adjusting for clinical, lifestyle and behavioral factors, and previous history of cardiovascular disease, twins with AHI ≥15 had 3.6 higher odds (95% CI, 1.5–8.9) of an abnormal total severity score, defined as a score ≥100, and for each 5-point increment in AHI, the odds of abnormality increased by 20% (95% CI, 7%-34%). Twin pairs where both twins had OSA exhibited the greatest risk. There were no differences in measures of ischemia and absolute myocardial blood flow and flow reserve by AHI status. Conclusions: OSA is associated with myocardial perfusion abnormalities that suggest prior subclinical myocardial scarring or infarction. Early environmental factors that affect both twins equally may play a role and should be further explored. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the choriocapillaris changes associated with pachychoroid pigment epitheliopathy (PPE) in comparison with healthy eyes. Methods: Nine 3 × 3 mm macular optical coherence tomography angiography images were acquired in patients with PPE and age-matched healthy participants. Multiple en face image averaging of the choriocapillaris was binarized for quantitative image analysis of the flow voids. In PPE eyes, we evaluated the presence of pachyvessels and the association between the location of the choriocapillaris flow deficit and pachyvessels. Results: Thirty-two eyes with PPE and 30 eyes of healthy participants were included. In PPE eyes, the mean total area (1.16 ± 0.18 vs. 0.91 ± 0.16, p < 0.001) and average size of the flow voids (790 ± 144 vs. 520 ± 138; p < 0.001) were significantly larger than those in control eyes. Composite images of the choriocapillaris and choroid showed choriocapillaris flow deficits just above and outside the pachyvessels. The mean proportion of the flow void area overlying the pachyvessels against the whole flow void area of the choriocapillaris was 21.3% ± 10.2% (9.38%-44.42%) in PPE eyes. Conclusions: In PPE eyes, the blood flow area of the choriocapillaris decreased diffusely within the macular area compared to control eyes, and the choriocapillaris flow deficit was not necessarily related to pachyvessel location. [ABSTRACT FROM AUTHOR]

Busana et al. (doi.org/10.1152/japplphysiol.00871.2020) published 5 patients with COVID-19 in whom the fraction of non-aerated lung tissue had been quantified by computed tomography. They assumed that shunt flow fraction was proportional to the non-aerated lung fraction, and, by randomly generating 106 different bimodal distributions for the ventilation-perfusion (V˙/Q˙) ratios in the lung, specified as sets of paired values { V˙i,Q˙i }, sought to identify as solutions those that generated the observed arterial partial pressures of CO2 and O2 (PaCO2 and PaO2). Our study sought to develop a direct method of calculation to replace the approach of randomly generating different distributions, and so provide more accurate solutions that were within the measurement error of the blood-gas data. For the one patient in whom Busana et al. did not find solutions, we demonstrated that the assumed shunt flow fraction led to a non-shunt blood flow that was too low to support the required gas exchange. For the other four patients, we found precise solutions (prediction error < 1x10-3 mmHg for both PaCO2 and PaO2), with distributions qualitatively similar to those of Busana et al. These distributions were extremely wide and unlikely to be physically realisable, because they predict the maintenance of very large concentration gradients in regions of the lung where convection is slow. We consider that these wide distributions arise because the assumed value for shunt flow is too low in these patients, and we discuss possible reasons why the assumption relating to shunt flow fraction may break down in COVID-19 pneumonia. [ABSTRACT FROM AUTHOR]

Peripheral artery disease (PAD) is a systemic vascular disease of the legs that results in a blockage of blood flow from the heart to the lower extremities. Now one of the most common causes of mortality in the U.S., the first line of therapy for PAD is to mechanically open the blockages using balloon angioplasty. Coating the balloons with antiproliferative agents can potentially reduce vessel re-narrowing, or restenosis after surgical intervention, but current drug-coated balloons releasing chemotherapy agents like paclitaxel have in some cases shown increased mortality long-term. Our aim was to design a novel drug-coated balloon using a polymeric nanodelivery system for a sustained release of polyphenols that reduce restenosis but with reduced toxicity compared to chemotherapy agents. Poly (lactic-co-glycolic acid) (PLGA) nanoparticles with entrapped quercetin, a dimethoxy quercetin (rhamnazin), as well as quercetin covalently attached to PLGA, were developed. Balloon catheters were coated with polymeric nanoparticles using an ultrasonic method, and nanoparticle characteristics, drug loading, coating uniformity and drug release were determined. The adhesion of nanoparticles to vascular smooth muscle cells and the antiproliferative effect of nano-delivered polyphenols were also assessed. Of the nanoparticle systems tested, those with covalently attached quercetin provided the most sustained release over a 6-day period. Although these particles adhered to cells to a smaller extent compared to other nanoparticle formulations, their attachment was resistant to washing. These particles also exhibited the greatest anti-proliferative effect. In addition, their attachment was not altered when the cells were grown in calcifying conditions, and in PAD tissue calcification is typically a condition that impedes drug delivery. Moreover, the ultrasonic coating method generated a uniform balloon coating. The polymeric nanoparticle system with covalently attached quercetin developed herein is thus proposed as a promising platform to reduce restenosis post-angioplasty. [ABSTRACT FROM AUTHOR]

Objective: Measures of Doppler blood flow velocity profiles are an integral part of monitoring fetal well-being during pregnancy. These examinations are performed at different times of the day and at different maternal meal states. In uncomplicated pregnancies, we assessed the effect of a standardized maternal meal on middle cerebral artery (MCA) and umbilical artery (UA) Doppler blood flow velocity pulsatility indices (PIs) and MCA peak systolic velocity (PSV). Methods: In this prospective single-blinded crossover study 25 healthy women were examined at 36 weeks of pregnancy. The first examination was performed in the morning following overnight fast, and repeated after extended fast (state A), and after a standard breakfast meal (state B). Results: Irrespective of maternal prandial status, the MCA-PI values were lower in the 2nd compared to the 1st examination (-0.187; p = 0.071, and -0.113; p = 0.099, state A and B, respectively). Compared to the values in the 1st examination, the UA-PI values, were higher after extended fast (0.014; p = 0.436), and lower post-prandially (-0.036; p = 0.070). The difference (state B minus state A) between the meal states were not significant (0.074; p = 0.487 and -0.050; p = 0.058, for MCA-PI and UA-PI, respectively). Adjusting for the possible influence of fetal heart rate on MCA-PI and UA-PI, the differences between meal states remained non-significant (p = 0.179, p = 0.064, respectively). The MCA-PSV values increased after the meal (6.812; p = 0.035), whereas no increase was observed following extended fast (0.140; p = 0.951). The difference in MCA-PSV values between the two meal states was not significant (6.672; p = 0.055). Conclusion: Our results demonstrate possible diurnal variations in MCA-PI and UA-PI, with and without adjustment for fetal heart rate, that seem to be unaffected by maternal meal intake in healthy pregnancies. [ABSTRACT FROM AUTHOR]

Arterial stenosis is a common cardiovascular disease that restricts blood flow. A stenotic blood vessel creates tangent stress pressure, which lessens the arterial side and causes an aneurysm. The primary purpose of this study is to investigate blood flowing via an inclination pipe with stricture and expansion after stricture (widening) underneath the influence of a constant incompressible Casson liquid flowing with the magnetism field. The relations for surface shearing stress, pressure drop, flow resistance, and velocity are calculated analytically by applying a mild stenosis approximation. The effect of different physical characteristics on liquid impedance to flowing, velocity, and surface shearing stress are studied. With a non-Newtonian aspect of the Casson liquid, the surface shearing stress declines, and an impedance upturn. Side resistivity and shear-stress increase with the elevations of stricture, whilst together decreasing with a dilatation height. [ABSTRACT FROM AUTHOR]

Purpose: The current study aimed to investigate the time course of changes in choroidal circulation hemodynamics and their relationship to systemic circulation dynamics during the normal menstrual cycle in young, healthy women using laser speckle flowgraphy (LSFG). Methods: This prospective study included 26 eyes from 13 young, healthy women (21.3 ± 4.0 years) with a normal menstrual cycle and 24 eyes from 12 young, healthy men (21.8 ± 4.4 years) as a control group. The macular mean blur rate (MBR), a quantitative index of relative blood flow velocity in the choroid, was measured using LSFG. MBR, intraocular pressure (IOP), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and ocular perfusion pressure (OPP) were evaluated in the late follicular phase and mid-luteal phase in women and at baseline and 10 days after baseline in men, respectively. Results: In the female group, IOP, SBP, DBP, MBP, and OPP values were significantly higher in the mid-luteal phase than those observed in the late follicular phase (P = 0.035, P < 0.001, P = 0.041, P = 0.001, P = 0.014, respectively). The average macular MBR values in the late follicular phase and mid-luteal phase were 12.7 ± 5.3 and 13.7 ± 6.6 (+7.7 ± 19.4%), representing a significant increase in the mid-luteal phase (P = 0.041). The rate of change in MBR exhibited a significant positive correlation with changes in DBP and MBP (R = 0.456, P = 0.019 and R = 0.474, P = 0.014). However, there were no significant changes in any of the factors in the male group during the study period. Conclusions: Our results suggest that in young, healthy women with a normal menstrual cycle, choroidal blood flow velocity decreases during the late follicular phase and increases during the mid-luteal phase, depending on systemic circulatory dynamics. [ABSTRACT FROM AUTHOR]

Purpose: Studies using functional magnetic resonance imaging and positron-emission tomography suggest that many regions of the brain are activated by such complex muscle activity. Although these studies demonstrated relative increases in blood flow in some brain regions with increased neural activity, whether or not the absolute value of cerebral blood flow increases has yet to be elucidated. It also remains unknown whether playing musical instruments affects cerebral blood flow. The aim of this study was to determine the impact of playing a musical instrument on blood flow velocity in the middle cerebral artery (MCAv) by using Doppler ultrasound to measure absolute values of arterial flow velocity. Methods: Thirteen musicians performed three pieces of music with different levels of difficulty: play for the first time (FS), music in practice (PR) and already mastered (MS) on either piano or violin. MCAv was recorded continuously from 10 min before until 10 min after playing. Associations between the cerebral blood flow response and blood pressure and gas-exchange variables were examined. Results: PR and MS significantly increased the MCAv. The blood pressure increased significantly in performances of all difficulty levels except for MS. There were no significant changes in exhaled gas variables during the performance. Conclusion: These findings suggest that playing a musical instrument increases MCAv, and that this change is influenced by the difficulty of the performance. [ABSTRACT FROM AUTHOR]

Purpose: We examined the effects of aging and exercise habits on the ocular blood flow (OBF) and its profiles throughout the optic nerve head region and choroidal area. We hypothesized that exercise habits reduce the stiffness of vessels in the ocular circulation, which generally increases with aging. Methods: Participants in a medical checkup program (698 males and 192 females aged 28 to 80 years) were categorized into 2 groups (with and without exercise habits) based on participant self-reporting and the definition of the Ministry of Health, Labor and Welfare of Japan (MHLW). OBF in the right eye was measured and analyzed using laser speckle flowgraphy. The blowout time (BOT), which is the time during which the blood flow is higher than half of the mean of the minimum and maximum signals during one heartbeat, was calculated as an index of the blood flow profile. BOT has been used as an indicator of the flexibility of blood vessels. Results: BOT significantly decreased with aging. Neither the self-reported nor MHLW-based exercise habits significantly affected the ocular circulation. Conclusion: These results indicate that the stiffness of the ocular vessels increases with aging, and this cannot be prevented by exercise habits. [ABSTRACT FROM AUTHOR]

Purpose: To test the hypothesis that mild chronic hyperoxia treatment would improve retinal function despite a progressive decline in ocular blood flow in the DBA/2J mouse model of glaucoma. Materials and methods: DBA/2J mice were treated with chronic mild hyperoxia (30% O2) beginning at 4.5 months of age or were untreated by giving normal room air. Retinal and choroidal blood flow (RBF and ChBF, respectively) were measured at 4, 6, and 9 months of age by MRI. Blood flow was additionally measured under hypercapnia challenge (5% CO2 inhalation) to assess vascular reactivity. Intraocular pressure (IOP) was measured using a rebound tonometer at the same time points. Scotopic flash electroretinograms (ERGs) were recorded at 9 months of age. Results: Both ChBF and RBF were reduced and significantly affected by age (p < 0.01), but neither were significantly affected by O2-treatment (p > 0.05). ChBF significantly increased in response to hypercapnia (p < 0.01), which was also unaffected by O2-treatment. Significant effects of age (p < 0.001) and of the interaction of age with treatment (p = 0.028) were found on IOP. IOP significantly decreased in O2-treated mice at 6 months compared to 4 months of age (p < 0.001), while IOP trended to increase with age in untreated mice. The amplitude of the b-wave from ERG was significantly increased in O2-treated DBA/2J compared to the untreated mice (p = 0.012), while the a-wave and oscillatory potentials were not significantly affected (p > 0.05). Conclusion: This study investigated the effects of chronic mild hyperoxia on retinal function and on retinal and choroidal blood flow in a mouse model of glaucoma. Retinal function was improved in the O2-treated mice at late stage, despite a progressive decline of RBF and ChBF with age that was comparable to untreated mice. [ABSTRACT FROM AUTHOR]

A quick, reliable, and reproducible biological assay to distinguish individuals with possible life-threatening risk following radiological or nuclear incidents remains a quest in biodosimetry. In this paper, we examined the use of a γ-H2AX assay as an early dose estimation for rapid triage based on both flow cytometry and image analyses. In the experiment, whole blood from 11 donors was irradiated ex vivo inside a water phantom by gamma rays from Co-60 at 0.51 Gy/min. After the lysis of red blood cells, the white blood cells were collected for immunofluorescence labeling of γ-H2AX, CD45, and nuclear stained for signal collection and visualization. Analysis by flow cytometry showed that the relative γ-H2AX intensities of lymphocytes and granulocytes increased linearly with absorbed doses from 0 to 6 Gy with a large variation among individuals observed above 2 Gy. The relative γ-H2AX intensities of lymphocytes assessed by two different laboratories were highly correlated (ICC = 0.979). Using confocal microscopic images, γ-H2AX foci were observed to be discretely distributed inside the nuclei and to increase proportionally with doses from 0 to 2 Gy, whereas large plagues of merged foci appeared at 4 and 6 Gy, resulting in the saturation of foci counts above 4 Gy. The number of total foci per cell as well as the number of foci per plane were significantly different at 0 vs 1 and 2 vs 4 Gy doses (p < 0.01). Blind tests at 0.5 Gy and 1 Gy doses showed that dose estimation by flow cytometry had a mean absolute difference of less than 0.5 Gy from the actual value. In conclusion, while flow cytometry can provide a dose estimation with an uncertainty of 0.5 Gy at doses ≤ 1 Gy, foci counting can identify merged foci that are prominent at doses ≥ 4 Gy. [ABSTRACT FROM AUTHOR]

Myocardial ischemia occurs when blood flow to the heart is reduced, preventing the heart muscle from receiving enough oxygen required for survival. Several anatomical and electrophysiological changes occur at the ischemic core (IC) and border zone (BZ) during myocardial ischemia, for example, gap junctional remodeling, changes in ionic channel kinetics and electrophysiologic changes in cell excitability, which promote the development of cardiac arrhythmia. Ephaptic coupling (EpC), which is an electrical field effect developed in the shared cleft space between adjacent cells, has been suggested to rescue the conduction when gap junctions are impaired, such as myocardial ischemia. In this manuscript, we explored the impact of EpC, electrophysiological and anatomical components of myocardial ischemia on reentry termination during non-ischemic and ischemic condition. Our results indicated that EpC and BZ with complex geometry have opposite effects on the reentry termination. In particular, the presence of homogeneous EpC terminates reentry, whereas BZ with complex geometry alone facilitates reentry by producing wave break-up and alternating conduction block. The reentry is terminated in the presence of homogeneous or heterogeneous EpC despite the presence of complex geometry of the BZ, independent of the location of BZ. The inhibition of reentry can be attributed to a current-to-load mismatch. Our results points to an antiarrhythmic role of EpC and a pro-arrhythmic role of BZ with complex geometry. [ABSTRACT FROM AUTHOR]

Purpose: This study compared proximal and distal embolization of the splenic artery (SA) in patients with splenic artery steal syndrome (SAS) after orthotopic liver transplantation (OLT) regarding post interventional changes of liver function to identify an ideal location of embolization. Methods and materials: 85 patients with SAS after OLT treated with embolization of the SA between 2007 and 2017 were retrospectively reviewed. Periinterventional DSA was used to assess treatment success and to stratify patients according to the site of embolization. Liver function was assessed using following laboratory values: bilirubin, albumin, gamma-glutamyl transferase, glutamat-pyruvat-transaminase (GPT), glutamic-oxaloacetic transaminase (GOT), Alkaline Phosphatase (ALP), aPTT, prothrombin time and thrombocyte count. Descriptive statistics were used to summarize the data. Median laboratory values of pre, 1- and 3-days, as well as 1-week and 1-month post-embolization were compared between the respective embolization sites using linear mixed model regression analysis. Results: All procedures were technically successful and showed an improved blood flow in the hepatic artery post-embolization. Ten Patients were excluded due to re -intervention or inconsistent image documentation. Pairwise comparison using linear mixed model regression analysis showed a significant difference between proximal and distal embolization for GPT (57.0 (IQR 107.5) vs. 118.0 (IQR 254.0) U/l, p = 0.002) and GOT (48.0 (IQR 48.0) vs. 81.0 (IQR 115.0) U/l, p = 0.008) 3-days after embolization as well as median thrombocyte counts 7-days after embolization (122 (IQR 108) vs. 83 (IQR 74) in thousands, p = 0.014). For all other laboratory values, no statistically significant difference could be shown with respect to the embolization site. Conclusion: We conclude that long-term outcomes after embolization of the SA in the scenario of SAS after OLT are irrespective of the site of embolization of the SA, whereas a proximal embolization potentially facilitates earlier normalization of liver function. Choice of technique should therefore be informed by anatomical conditions, safety considerations and preferences of the interventionalist. [ABSTRACT FROM AUTHOR]

Background: Metformin is prescribed to women with polycystic ovary syndrome (PCOS) to prevent pregnancy complications. Children exposed to metformin vs. placebo in utero, have increased head circumference at birth and are more overweight and obese at 8 years of age. Also, maternal PCOS-status seems to alter the long-term cardio-metabolic health of offspring. We hypothesized that the long-term effects of metformin-exposure and/or maternal PCOS may be mediated by circulatory adaptations during fetal life. Material and methods: This is a sub-study of a larger double-blinded, placebo-controlled trial, where women with PCOS were randomized to metformin (2g/day) or placebo in pregnancy, a total of 487 women. A sub-group of participants (N = 58) took part in this sub-study and had an extended ultrasound examination at gestational week 32, including blood flow velocity and diameter measurements of the umbilical vein (UV), the ductus venosus (DV) and the portal vein (PV). Blood flow volume was calculated and adjusted for estimated fetal weight (EFW) (normalized flow). Metformin exposed fetuses were compared to placebo exposed fetuses. Fetuses of mothers with PCOS (metformin [n = 30] and placebo [n = 28]) were compared to a low-risk reference population (N = 160) by z-score statistics. Results: There was no difference in fetal liver flow between metformin vs. placebo-exposed fetuses. Fetuses of mothers with PCOS had higher EFW (0.63 [95% CI 0.44–0.83] p<0.001), lower normalized UV, DV, PV, and lower total venous liver blood flows than the reference population. Conclusion: Metformin during pregnancy did not affect fetal liver blood-flow. In our population, maternal PCOS-status was associated with reduced total venous liver blood-flow, which may explain altered growth and metabolism later in life. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate neuronal and vascular functional deficits in the retina and their association in a diabetic mouse model. We measured electroretinography (ERG) responses and choroidal and retinal blood flow (ChBF, RBF) with magnetic resonance imaging (MRI) in healthy and diabetic mice under basal conditions and under hypercapnic challenge. Methods: Ins2Akita diabetic (Diab, n = 8) and age-matched, wild-type C57BL/6J mice (Ctrl, n = 8) were studied under room air and moderate hypercapnia (5% CO2). Dark-adapted ERG a-wave, b-wave, and oscillatory potentials (OPs) were measured for a series of flashes. Regional ChBF and RBF under air and hypercapnia were measured using MRI in the same mice. Results: Under room air, Diab mice had compromised ERG b-wave and OPs (e.g., b-wave amplitude was 422.2±10.7 μV in Diab vs. 600.1±13.9 μV in Ctrl, p < 0.001). Under hypercapnia, OPs and b-wave amplitudes were significantly reduced in Diab (OPs by 30.3±3.0% in Diab vs. -3.0±3.6% in Ctrl, b-wave by 17.9±1.4% in Diab vs. 1.3±0.5% in Ctrl). Both ChBF and RBF had significant differences in regional blood flow, with Diab mice having substantially lower blood flow in the nasal region (ChBF was 5.4±1.0 ml/g/min in Diab vs. 8.6±1.0 ml/g/min in Ctrl, RBF was 0.91±0.10 ml/g/min in Diab vs. 1.52±0.24 ml/g/min in Ctrl). Under hypercapnia, ChBF increased in both Ctrl and Diab without significant group difference (31±7% in Diab vs. 17±7% in Ctrl, p > 0.05), but an increase in RBF was not detected for either group. Conclusions: Inner retinal neuronal function and both retinal and choroidal blood flow were impaired in Diab mice. Hypercapnia further compromised inner retinal neuronal function in diabetes, while the blood flow response was not affected, suggesting that the diabetic retina has difficulty adapting to metabolic challenges due to factors other than impaired blood flow regulation. [ABSTRACT FROM AUTHOR]

Background: Right (R) or left (L) ventricular outflow tract (VOT) obstruction can be either a dynamic phenomenon or a congenital anatomic lesion, which requires a prompt and optimal timing of treatment to avoid a pathological ventricular remodelling. Objective: To develop a simple and reliable numerical tool able to relate the R/L obstruction size with the pressure gradient and the cardiac output. To provide indication of the obstruction severity and be of help in the clinical management of patients and designing the surgical treatment for obstruction mitigation. Methods: Blood flow across the obstruction is described according to the classical theory of one-dimensional flow, with the obstruction uniquely characterized by its size. Hemodynamics of complete circulation is simulated according to the lumped parameter approach. The case of a 2 years-old baby is reproduced, with the occlusion placed in either the R/ or the L/VOT. Conditions from wide open to almost complete obstruction are reproduced. Results: Both R/LVOT obstruction in the in-silico model resulted in an increased pressure gradient and a decreased cardiac output, proportional to the severity of the VOT obstruction and dependent on the R/L location of the obstruction itself, as it is clinically observed. Conclusion: The in-silico model of ventricular obstruction which simulates pressure gradient and/or cardiac output agrees with clinical data, and is a first step towards the creation of a tool that can support the clinical management of patients from diagnosis to surgical treatments. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the feasibility of dynamic contrast enhanced magnetic resonance imaging (DCE MRI) and measure values of in vivo placental perfusion in women. Methods: This study was part of the Placentimage trial (NCT01092949). Gadolinium-chelate (Gd) enhanced dynamic MRI was performed two days before termination of pregnancies at 16 to 34 weeks gestational age (GA). Quantitative analysis was performed using one-compartment intravascular modeling. DCE perfusion parameters were analyzed across GA and were compared in IUGR and AGA fetuses. Results: 134 patients were enrolled. After quality control check, 62 DCE MRI were analyzed including 48 and 14 pregnancies with normal and abnormal karyotypes, respectively. Mean placental blood flow was 129±61 mL/min/100ml in cases with normal karyotypes. Fetuses affected by IUGR (n = 13) showed significantly lower total placental blood flow values than AGA fetuses (n = 35) (F total = 122±88 mL/min versus 259±34 mL/min, p = 0.002). DCE perfusion parameters showed a linear correlation with GA. Conclusions: Measuring placental perfusion in vivo is possible using DCE MRI. Although this study has many limitations it gives us the first DCE MRI values that provide a potential standard for future research into placental perfusion methods and suggests that placental functional parameters are altered in IUGR pregnancies. [ABSTRACT FROM AUTHOR]

Application of exposure to 50/60 Hz magnetic fields (MFs) has been conducted in the treatment of muscle pain and fatigue mainly in Japan. However, whether MFs could increase blood flow leading to muscle fatigue recovery has not been sufficiently tested. We investigated the acute effects of a 50 Hz sinusoidal MF at Bmax 180 mT on hemodynamics, electrocardiogram, and vascular endothelial function in healthy young men. Three types of regional exposures to a 50 Hz MF, i.e., forearm, upper arm, or neck exposure to MF were performed. Participants who received three types of real MF exposures had significantly increased ulnar arterial blood flow velocity compared to the sham exposures. Furthermore, after muscle loading exercise, MF exposure recovered hemoglobin oxygenation index values faster and higher than sham exposure from the loading condition. Moreover, participants who received real MF exposure in the neck region had significantly increased parasympathetic high-frequency activity relative to the sham exposure. The MF exposure in the upper arm region significantly increased the brachial artery flow-mediated dilation compared to the sham exposure. Computer simulations of induced in situ electric fields indicated that the order-of-magnitude estimates of the peak values were 100–500 mV/m, depending on the exposure conditions. This study provides the first evidence that a 50 Hz MF can activate parasympathetic activity and thereby lead to increase vasodilation and blood flow via a nitric oxide-dependent mechanism. Trial registration: UMIN Clinical Trial Registry (CTR) UMIN000038834. The authors confirm that all ongoing and related trials for this drug/intervention are registered. [ABSTRACT FROM AUTHOR]

Although quiescent hepatic stellate cells (HSCs) have been suggested to regulate hepatic blood flow, there is no direct evidence that quiescent HSCs display contractile abilities. Here, we developed a new method to quantitatively measure the contraction of single isolated HSCs and evaluated whether endothelin-1 (ET-1) induced contraction of HSCs in a non-activated state. HSCs isolated from mice were seeded on collagen gel containing fluorescent beads. The beads around a single HSC were observed gravitating toward the cell upon contraction. By recording the movement of each bead by fluorescent microscopy, the real-time contraction of HSCs was quantitatively evaluated. ET-1 induced a slow contraction of non-activated HSCs, which was inhibited by the non-muscle myosin II inhibitor blebbistatin, the calmodulin inhibitor W-7, and the ETA receptor antagonist ambrisentan. ET-1-induced contraction was also largely reduced in Ca2+-free conditions, but sustained contraction still remained. The tonic contraction was further diminished by the Rho-kinase inhibitor H-1152. The mRNA expression of P/Q-type voltage-dependent Ca2+ channels (VDCC), as well as STIM and Orai, constituents of store-operated channels (SOCs), was observed in mouse non-activated HSCs. ET-1-induced contraction was not affected by amlodipine, a VDCC blocker, whereas it was partly reduced by Gd3+ and amiloride, non-selective cation channel blockers. However, neither YM-58483 nor SKF-96365, which inhibit SOCs, had any effects on the contraction. These results suggest that ET-1 leads to Ca2+-influx through cation channels other than SOCs and produces myosin II-mediated contraction of non-activated HSCs via ETA receptors, as well as via mechanisms involving Ca2+-calmodulin and Rho kinase. [ABSTRACT FROM AUTHOR]

Background and aim: Hemodynamic monitoring and cardiac output (CO) assessment in the ICU have been trending toward less invasive methods. Carotid blood flow (CBF) was suggested as a candidate for CO assessment. The present study aimed to test the value of carotid artery ultrasound analysis in prediction of mortality in pediatric patients with septic shock. Methodology/Principal finding: Forty children with septic shock were included in the study. Upon admission, patients were subjected to careful history taking and thorough clinical examination. The consciousness level was assessed by the Glasgow Coma Scale (GCS). Laboratory assessment included complete blood count, C-reactive protein, arterial blood gases, serum electrolytes, and liver and kidney function tests. Electrical cardiometry was used to evaluate hemodynamic parameters. Patients were also subjected to transthoracic 2-D echocardiography. CBF was evaluated using GE Vivid S5 ultrasound device through dedicated software. At the end of study, 14 patients (35.0%) died. It was found that survivors had significantly higher CBF when compared non-survivors [median (IQR): 166.0 (150.0–187.3) versus 141.0 (112.8–174.3), p = 0.033]. In addition, it was noted that survivors had longer ICU stay when compared with non-survivors [16.5 (9.8–31.5) versus 6.5 (3.0–19.5) days, p = 0.005]. ROC curve analysis showed that CBF could significantly distinguish survivors from non-survivors [AUC (95% CI): 0.3 (0.11–0.48), p = 0.035] (Fig 2). Univariate logistic regression analysis identified type of shock [OR (95% CI): 28.1 (4.9–162.4), p<0.001], CI [OR (95% CI): 0.6 (0.43–0.84), p = 0.003] and CBF [OR (95% CI): 0.98 (0.96–0.99), p = 0.031]. However, in multivariate analysis, only type of shock significantly predicted mortality. Conclusions: CBF assessment may be a useful prognostic marker in children with septic shock. [ABSTRACT FROM AUTHOR]