Artery Blood Flow Research Articles

Statin treatment intensity and cerebral vasomotor reactivity response in patients with ischemic stroke.

Cerebral vasomotor reactivity (VMR) is vital for regulating brain blood flow and maintaining neurological function. Impaired cerebral VMR is linked to a higher risk of stroke and poor post-stroke outcomes. This study explores the relationship between statin treatment intensity and VMR in patients with ischemic stroke. Seventy-four consecutive patients (mean age 69.3 years, 59.4% male) with recent ischemic stroke were included. VMR levels were assessed 4 weeks after the index stroke using transcranial Doppler, measuring the breath-holding index (BHI) as an indicator of the percentage increase in middle cerebral artery blood flow (higher BHI signifies higher VMR). Multistep multivariable regression models, adjusted for demographic and cerebrovascular risk factors, were employed to examine the association between statin intensity treatment and BHI levels. Forty-one patients (55%) received high-intensity statins. Patients receiving high-intensity statins exhibited a mean BHI of 0.85, whereas those on low-intensity statins had a mean BHI of 0.67 (mean difference 0.18, 95% confidence interval: 0.13-0.22, p-value<.001). This significant difference persisted in the fully adjusted model (adjusted mean values: 0.84vs. 0.68, p-value:.008). No significant differences were observed in BHI values within patient groups on high-intensity or low-intensity statin therapy (all p-values>.05). Furthermore, no significant association was found between baseline low-density lipoprotein (LDL) levels and BHI. High-intensity statin treatment post-ischemic stroke is linked to elevated VMR independent of demographic and clinical characteristics, including baseline LDL level. Further research is needed to explore statin therapy's impact on preserving brain vascular function beyond lipid-lowering effects.

Steady Flow Left Ventricle Unloading Is Superior to Pulsatile Pressure Augmentation Venting During Venoarterial Extracorporeal Membrane Oxygenation Support.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) shunts venous blood to the systemic arterial circulation to provide end-organ perfusion while increasing afterload that may impede left ventricle (LV) ejection and impair cardiac recovery. To maintain flow across the aortic valve and reduce risk of lethal clot formation, secondary mechanical circulatory support (MCS) devices are increasingly used despite limited understanding of their effects on cardiac function. This study sought to quantify the effects of VA-ECMO and combined with either intraaortic balloon pump (IABP) or percutaneous ventricular assist device (pVAD) on LV physiologic state and perfusion metrics in a porcine model of acute cardiogenic shock. Shock was induced through serial left anterior descending artery microbead embolization followed by initiation of VA-ECMO support and then placement of either IABP or pVAD. Hemodynamic measurements, LV pressure-volume loops, and carotid artery blood flow were evaluated before and after institution of combined MCS. The IABP decreased LV end-diastolic pressure by a peak of 15% while slightly increasing LV stroke work compared with decreases of more than 60% and 50% with the pVAD, respectively. The pVAD also demonstrated increased coronary perfusion and systemic pressure gradients in comparison to the IABP. Combined support with VA-ECMO and pVAD improves cardiovascular state in comparison to IABP.

Assessment of arterial blood flow in the microvasculature of the lower extremities in patients with chronic ischemia using a single-photon emission computed tomography (SPECT)

Introduction. Obliterating atherosclerosis of the lower extremity vessels is a chronic, steadily progressive disease of the leg arteries, with a high risk of limb amputation and death. Timely diagnosis and adequate treatment will help slow the disease progression, maintain the patient’s good health for a long time and avoid complications. Purpose. To study arterial blood flow in the microvasculature of the lower extremities, to qualitatively and quantitatively assess perfusion disturbances in functionally significant muscles of the lower extremities. Material and methods. Radionuclide examination of the main vessels and microvasculature of the lower extremities was performed in 36 patients, five of them with a diagnosis of lower extremity obliterating atherosclerosis in dynamics. Radiopharmaceuticals was administered through a catheter installed endovascularly above the aortic bifurcation when patients underwent arteriography of the lower extremity vessels, which also involves intra-arterial administration of a radiopaque contrast agent. Results. When processing the radiological study results, we visually assessed the distribution of radiopharmaceuticals in the vascular bed of the lower extremities, identified the asymmetry in the accumulation of radiopharmaceuticals as a percentage, quantified the accumulation of radiopharmaceutical pulses in the projection of the pelvic, thigh, leg and foot muscles, determining the level of accumulation in each of the areas of interest as a percentage. The radiological study results and direct aortic arteriography of the lower extremities with determination of the level of arterial stenosis confirmed the ischemic nature of the pain syndrome; and in the control study, the effectiveness of treatment with an improvement in perfusion parameters. Conclusions. Intra-arterial administration of radiopharmaceuticals makes it possible to assess the condition of the peripheral arterial bed, which has a significant role in the prognosis of lower extremity atherosclerosis and the results of reconstructive interventions. The method makes possible a hybrid topometric comparison of arterio-perfusion maps for diagnosis, planned treatment and monitoring of its results in dynamics.

Effect of FEMOKLIM on the state of blood vessels in hypoestrogenemia and arterial hypertension

The article presents the results of duplex scanning of the common carotid arteries (CCA) and assessment of the structural and functional state of the vascular bed of 57 women with arterial hypertension (AH) with hypoestrogenemia. It was found that with hypertension with a reduced level of estradiol, the lumen of the OCA increases, the speed of blood flow in the carotid arteries decreases, which indicates vascular remodeling. In the studied patients, in every third case, an inertial type of vasomotor reaction is detected before treatment, which indicates the contribution of dishormonosis to the progression of hypertension due to the development of endothelial dysfunction. Combined therapy with phytoestrogens and ACE inhibitors improves the structural and functional characteristics of the vascular wall, reduces arterial stiffness. The drug Femoklim is a source of phytohormones, hormones of entomological origin and natural antioxidants, has a positive effect on the state of the vascular system, improves blood microcirculation, is a capillary protector, has a complex harmonizing effect on the body.

Pilot study to evaluate the safety and effectiveness of etidronate treatment for arterial calcification due to deficiency of CD73 (ACDC).

Arterial calcification due to deficiency of CD73 (ACDC; OMIM 211800) is a rare genetic disease resulting in calcium deposits in arteries and small joints causing claudication, resting pain, severe joint pain, and deformities. Currently, there are no standard treatments for ACDC. Our previous work identified etidronate as a potential targeted ACDC treatment, using in vitro and in vivo disease models with patient-derived cells. In this study, we test the safety and effectiveness of etidronate in attenuating the progression of lower-extremity arterial calcification and vascular blood flow based on the computed tomography (CT) calcium score and ankle-brachial index (ABI). Seven adult patients with a confirmed genetic diagnosis of ACDC were enrolled in an open-label, nonrandomized, single-arm pilot study for etidronate treatment. They took etidronate daily for 14 days every 3 months and were examined at the NIH Clinical Center bi-annually for 3 years. They received a baseline evaluation as well as yearly follow up after treatment. Study visits included imaging studies, exercise tolerance tests with ABIs, clinical blood and urine testing, and full dental exams. Etidronate treatment appeared to have slowed the progression of further vascular calcification in lower extremities as measured by CT but did not have an effect in reversing vascular and/or periarticular joint calcifications in our small ACDC cohort. Etidronate was found to be safe and well tolerated by our patients and, despite the small sample size, appeared to show an effect in slowing the progression of calcification in our ACDC patient cohort.(ClinicalTrials.gov Identifier NCT01585402).

Bioresorbable Scaffolds for Below-the-Knee Arterial Disease: A Literature Review of New Developments.

This review aimed to explore the therapeutic effect of bioabsorbable stents in the inferior genicular artery, from the emergence of absorbable bare metal stents to the latest technology in polymer and anti-proliferative eluting drugs mixed with coated bioresorbable vascular stents (BVSs). Currently, there are conflicting data regarding the safety and effectiveness of BVSs in infrapopliteal artery interventions, especially compared to the current generation of drug-eluting stents (DESs). This review will cover the existing data on BVSs in reconstructing the infrapopliteal arterial blood flow and active clinical trials for future iterations of BVSs. In terms of primary patency rate and target lesion revascularization rate, the available research on the effectiveness of BVSs in reconstructing the infrapopliteal arterial blood flow suggests that a BVS is compatible with current DESs within 3-12 months; long-term data have not yet been reported. The ABSORB BVS is the most studied BVS in cardiovascular disease (CAD). Initially, the ABSORB BVS showed promising results. Managing intricate regions in peripheral artery disorders, such as branching or lengthy lesions, continues to be a formidable undertaking. In contrast to the advanced narrowing of arteries seen in standard permanent stent procedures, bioabsorbable stents have the potential to promote the expansion and beneficial merging of blood channels in the latter stages. Furthermore, incorporating stents and re-establishing the endothelial function can diminish the probability of restenosis or thrombosis. Nevertheless, the extent to which bioabsorbable stents may simultaneously preserve arterial patency and guarantee their structural integrity remains uncertain. The powerful and intricate mechanical stresses exerted by the blood in the superficial femoral artery and popliteal artery can cause negative consequences on any implant inserted into the vessel, regardless of its composition, even metal. Furthermore, incorporating stents is advantageous for treating persistent occlusive lesions since it does not impact later treatments, including corrective bypass operations. Evidence is scarce about the use of bioabsorbable stents in treating infrapopliteal lesions. Utilizing bioabsorbable stents in minor infrapopliteal lesions can successfully maintain the patency of the blood vessel lumen, whereas balloon angioplasty cannot offer this benefit. The primary focus of testing these materials is determining whether bioabsorbable scaffolds can provide adequate radial force in highly calcified elongated lesions. Indeed, using "-limus" medication elution technology in conjunction with bioabsorbable stents has previously offered clinical benefits in treating the popliteal artery, as evidenced by limited trials.BVSs for peripheral arterial disease (PAD) show promise and have the potential to offer a less inflammatory and more vessel-friendly option compared to permanent metallic stents. However, current evidence does not yet allow for a universal recommendation for their use. Thus, ongoing, and future studies, such as those examining the newer generation of bioresorbable scaffolds (BRSs) with improved mechanical properties and resorption profiles, will be crucial in defining the role of BRSs in managing PAD.

Computational Analysis of Blood Flow in Healthy Pulmonary Arteries in Comparison to Repaired Tetralogy of Fallot Results: A Small Cohort Study

Characterization of the physiological hemodynamic environment in normal pulmonary arteries is a key factor in understanding pathological conditions. This study aimed to analyze the morphology and hemodynamics in the healthy adult pulmonary bifurcation in comparison to age-matched repaired Tetralogy of Fallot (rTOF) geometries. The pulmonary trunk of five healthy volunteers was reconstructed from 4D Flow-MRI data and was compared to rTOF results. Subject-specific boundary conditions were assigned in both the inlet and outlets of the models, and flow characteristics were analyzed computationally. The morphological and flow features were consistent among the healthy geometries, highlighting the ability of an averaged geometry derived from this small cohort to capture the main flow characteristics. A slightly higher mean time-averaged wall shear stress (TAWSS) was found in the right pulmonary artery, which was also the branch with a higher mean curvature and local Reynolds number. Compared to rTOF results, the averaged healthy geometry demonstrated more than an 8-fold lower value in TAWSS, with the individual patient-specific healthy volunteers showing further reduced TAWSS than the rTOF patients. These observations could be useful in clinical assessment and decision making based on hemodynamic indices.

Short communication: Characterizing arterial and venous blood gases over the gas exchange surface, the chorioallantoic membrane, of embryonic American alligators (Alligator mississippiensis) at two points of development

Assessments of arterial and venous blood gases are required to understand the function of respiratory organs in animals at different stages of development. We measured blood gases in the arteries entering and veins leaving the chorioallantoic membrane (CAM) in embryonic alligators (Alligator mississippiensis). The CAM accounts for virtually all gas exchange in these animals, and we hypothesized that the CAM vasculature would be larger in eggs incubated in hypoxia (10% O2 for 50% or 70% of incubation), which would be reflected in a lower partial pressure of CO2 (PCO2). Contrary to this hypothesis, our measurements revealed no effects of hypoxic incubation on PCO2, and seemingly no increase in vascularization of the CAM in response to incubation in 10% O2. PCO2 was lower on the venous side, but only significantly different from arterial blood at 70% of incubation. The calculated blood flow to the CAM increased with development and was lower in both groups of alligators that had been incubated in hypoxia. Future studies should include measurements of blood parameters taken from embryos held in conditions that mirror incubation O2 levels, in combination with direct measurements of CAM artery blood flow.

548 Metformin normalizes impaired renal and cardiac function in a rat model of transient undernutrition

OBJECTIVES/GOALS: In the U.S., over 4 million people including children experience transient periods of undernutrition annually. Cardio-metabolic and renal diseases are more prevalent in this population. We are investigating therapeutic strategies to reverse the long-term risk of these diseases in a rat model of transient undernutrition followed by refeeding. METHODS/STUDY POPULATION: Thirty six female Fischer rats (3-months of age) were initially divided into 2 groups. Half were fed regular chow (CT) while the other half were severely food restricted (sFR) by 60% from 0-2 weeks (wks) followed by refeeding from 2-14 wks (sFR-Refed). These 2 groups were then subdivided and treated ± metformin (Met) from wk 7 to wk 12 (n=9/group). High precision ultrasound was conducted on live rats to assess heart and kidney function immediately after the sFR period ended (wk 2) and at the end of the study (wk 14). At the conclusion of the experiment, the rats were sacrificed and the histology of the kidney and heart tissues were analyzed in hematoxylin and eosin-stained sections. The protein to DNA ratio was also calculated in homogenates from these tissues. RESULTS/ANTICIPATED RESULTS: In sFR-Refed rats, cardiac output (CO), heart rate (HR) and renal artery blood flow (RBF) were decreased by 11 ± 1.5%#, 7.0 ± 6.0% and 22 ± 0.6%#, respectively, compared to control (CT) rats; #p&lt;0.05. Mean glomerular diameter was reduced in the kidneys of sFR-refed rats compared to CT and this effect was attenuated by metformin treatment [(µm): CT, 406 ± 31; sFR-Refed, 383 ± 11, p&lt;0.06; CT+Met, 393 ± 18; sFR-Refed+Met, 407 ± 18*]. Furthermore, the mean cardiomyocyte thickness was reduced in sFR-Refed rats compared to controls while metformin treatment prevented this effect [(µm): CT, 16.4 ± 3.6; sFR-Refed, 11.5 ± 2.3#; CT+Met, 16.4 ± 3.6; sFR-Refed+Met, 15.9 ± 3.2*]. #p&lt;0.05 vs. CT, same treatment; *p&lt;0.05 vs. Met, same diet; two-way ANOVA. DISCUSSION/SIGNIFICANCE: These findings have promising implications for metformin use to mitigate long-term impairments in heart and kidney structure and function in individuals who have experienced bouts of undernutrition earlier in life for either voluntarily (e.g., very low calorie dieting) or involuntary (e.g., very low food security) reasons.

The effect of underwater massage during hot water immersion on acute cardiovascular and mood responses

PurposeThere is emerging evidence that demonstrates the health benefits of hot water immersion including improvements to cardiovascular health and reductions in stress and anxiety. Many commercially available hot tubs offer underwater massage systems which purport to enhance many benefits of hot water immersion, however, these claims have yet to be studied. MethodsTwenty participants (4 females) completed three, 30-min sessions of hot-water immersion (beginning at 39 °C) in a crossover randomized design: with air massage (Air Jet), water massage (Hydro Jet) or no massage (Control). Cardiovascular responses comprising; heart rate, blood pressure and superficial femoral artery blood flow and shear rate were measured. State trait anxiety, basic affect, and salivary cortisol were recorded before and after each trial. Data were analysed using a mixed effects model. ResultsPost immersion, heart rate increased (Δ31bpm, P < 0.001, d = 1.38), mean arterial blood pressure decreased (Δ16 mmHg, P < 0.001, d = −0.66), with no difference between conditions. Blood flow and mean shear rate increased following immersion (P < 0.001, Δ362 ml/min, d = 1.20 and Δ108 s−1, d = 1.00), but these increases were blunted in the Air Jet condition (P < 0.001,Δ171 ml/min, d = 0.43 and Δ52 s−1, d = 0.52). Anxiety and salivary cortisol were reduced (P = 0.003, d = −0.20, P = 0.014, d = −0.11), but did not vary between conditions. Enjoyment did not vary between conditions. ConclusionThese data demonstrate positive acute responses to hot water immersion on markers of cardiovascular function, anxiety, and stress. There was no additional benefit of water-based massage, while air-based massage blunted some positive vascular responses due to lower heat conservation of the water.

MiR-34a ameliorates arterial blood flow in rats with lower limb arteriosclerosis obliterans via Sirt1 signaling pathway.

In this study, we investigated the impact of microRNA-34a (miR-34a) on lower limb arteriosclerosis obliterans in rats through the Sirtuin 1 (Sirt1) signaling pathway. Thirty-six Sprague-Dawley rats were divided into normal, model, and miR-34a mimics groups. Rats in the normal group were raised normally, while the model group underwent lower limb arteriosclerosis obliterans induction and received saline injections. The miR-34a mimics group also underwent arteriosclerosis obliterans modeling but received miR-34a mimics injections. Immunohistochemistry revealed significantly increased vascular endothelial growth factor (VEGF) expression in both model and miR-34a mimics groups compared to the normal group, with the miR-34a mimics group showing higher levels. Western blotting indicated elevated Sirt1 protein expression in both non-normal groups, with the miR-34a mimics group exhibiting significantly higher levels. Quantitative polymerase chain reaction (qPCR) demonstrated higher levels of miR-34a, VEGF mRNA, and Sirt1 mRNA in the model group compared to the normal group, but significantly lower levels than the miR-34a mimics group. Enzyme-linked immunosorbent assay (ELISA) showed increased VEGF content in the model group compared to the normal group but decreased compared to the miR-34a mimics group. Hemorrheological detection revealed a reduced PU index in both non-normal groups compared to the normal group, with a significant increase in the miR-34a mimics group compared to the model group. Overall, miR-34a upregulation enhanced VEGF expression in rat blood vessels, ameliorating arterial blood flow in lower limb arteriosclerosis obliterans through the Sirt1 signaling pathway.

Computational simulation of blood flow in the right coronary artery and the interaction between the blood flow and the arterial wall

Computational simulation of blood flow in the right coronary artery and the interaction between the blood flow and the arterial wall

Antihistamine Medication Blunts Localized-Vibration-Induced Increases in Popliteal Blood Flow

Localized vibration (LV) of the lower leg increases arterial blood flow (BF). However, it is unclear how LV causes this increase. Understanding the mechanisms of this response could lead to the optimized future use of LV as a therapy. One possible mechanism of LV-mediated BF is through histamine release by mechanosensitive mast cells. The purpose of this study was to measure the BF response of 21 recreationally active young adults (11 male, 10 female, mean age 22.1 years) after 47 Hz and 10 min LV to the calf, with and without antihistamine medication (180 mg Fexofenadine). Each participant received both control (no antihistamine) and antihistamine (treatment) conditions separated by at least 24 h. BF ultrasound measurements (mean and peak blood velocity, volume flow, popliteal diameter, and heart rate) were taken before LV therapy and periodically for 19 min post LV. Using a cell means mixed model, we found that LV significantly increased the control mean blood velocity immediately post LV but did not significantly increase the antihistamine mean blood velocity immediately post LV. Therefore, we hypothesize that a primary mechanism of LV increase in BF is histamine release from mechano-sensing mast cells, and that this response is force-dependent.

Extended period of ventilation before delayed cord clamping augments left-to-right shunting and decreases systemic perfusion at birth in preterm lambs.

Previous studies have suggested that an extended period of ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. However, it is unknown whether this greater rise in PA flow is accompanied by increases in left ventricular (LV) output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale (FO), with decreased systemic arterial perfusion. Using an established preterm lamb birth transition model, this study compared the effect of a short (∼40s, n=11), moderate (∼2min, n=11) or extended (∼5min, n=12) period of initial mechanical lung ventilation before DCC on flow probe-derived perinatal changes in PA flow, LV output, total systemic arterial blood flow, ductal shunting and FO shunting. The LV output was relatively stable during initial ventilation but increased after DCC, with similar responses in all groups. Systemic arterial flow patterns displayed only minor differences during brief and moderate periods of initial ventilation and were similar after DCC. However, an increase in PA flow was augmented with an extended initial ventilation (P < 0.001), owing to an earlier onset of left-to-right ductal and FO shunting (P < 0.001), and was accompanied by a pronounced reduction in total systemic arterial flow (P=0.005) that persisted for 4min after DCC (P ≤ 0.039). These findings suggest that, owing to increased left-to-right shunting and a greater reduction in systemic arterial perfusion, an extended period of ventilation before DCC does not result in greater perinatal circulatory benefits than shorter periods of initial ventilation in the birth transition. KEY POINTS: Previous studies suggest that an extended period of initial ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. It is unknown whether this greater rise in PA flow is accompanied by an increased left ventricular output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale, with decreased systemic arterial perfusion. Anaesthetized preterm fetal lambs instrumented with central arterial flow probes underwent a brief (∼40s), moderate (∼2min) or extended (∼5min) period of ventilation before DCC. Perinatal changes in left ventricular output were similar in all groups, but extended initial ventilation augmented both perinatal increases in PA flow, owing to earlier onset and greater left-to-right ductal and foramen ovale shunting, and perinatal reductions in total systemic arterial perfusion. Extended ventilation before DCC does not confer a greater perinatal circulatory benefit than shorter periods of initial ventilation.

Prevalence of Erectile Dysfunction among Patients with Coronary Artery Disease

Both coronary artery disease (CAD) and erectile dysfunction (ED) are widespread illnesses that frequently coexist. Numerous triggering risk factors and pathophysiological mechanisms contribute to both diseases. Penile color Doppler ultrasound can serve as a crucial tool to evaluate penile arterial blood flow. Therefore, this study aims to assess the ED prevalence in CAD patients, to determine the socioeconomic and clinical profiles of the population, and to define risk factors of their development. The cross-sectional study included 100 male patients who were admitted to the coronary angiography (CAG) unit. Patients were asked if they had ED, and if present, it was graded using the International Index of Erectile Function 5. Right and left cavernosal arteries were examined using color Doppler and erection hardness to assess the peak systolic velocity (PSV) and end-diastolic velocity. Among the 52 cases that suffered from ED, most of the cases had mild grades (38.5%). All cases without ED (100%) had penile artery Doppler PSV findings ≥30 (cm/s) with an average Doppler PSV of 48.02 ± 7.49 cm/s for the right cavernosal arteries and 47.4 ± 7.17 cm/s for the left cavernosal arteries. Yet, 71.2% of cases with ED had penile artery Doppler PSV findings &lt;30 (cm/s) with an average Doppler PSV of 29.1 ± 7.57 cm/s for the right cavernosal arteries and 28.69 ± 7.11 cm/s for the left cavernosal arteries. Furthermore, by CAG, 50% of cases without ED had blockage not necessitating a coronary intervention (no significant disease) compared to 25% of cases with ED. There was positive correlation between advanced grade of ED and age (r = 0.327, P &lt;0.001), hypertension (r = 0.213, P = 0.033), DM (r = 0.253, P = 0.011), smoking (r = 0.202, P = 0.044), and severity of CAD (r = 0.332, P &lt;0.001). Patients with multivessel CAD have a significantly higher incidence and more severity of ED. Moreover, pathological penile vessels PSV (&lt;25 or &lt;30 cm/s) via Doppler ultrasound is mostly valuable as a noninvasive tool to define ED attributable to vascular impairment that may be antecedent to atherosclerosis in the coronary vessels.

Expression of Placental Lipid Transporters in Pregnancies Complicated by Gestational and Type 1 Diabetes Mellitus.

The objective of the study was to assess the expression of proteins responsible for placental lipid transport in term pregnancies complicated by well-controlled gestational (GDM) and type 1 diabetes mellitus (PGDM). A total of 80 placental samples were obtained from patients diagnosed with PGDM (n = 20), GDM treated with diet (GDMG1, n = 20), GDM treated with diet and insulin (GDMG2, n = 20), and a non-diabetic control group (n = 20). Umbilical and uterine artery blood flows were assessed by means of ultrasound in the period prior to delivery and computer-assisted quantitative morphometry of immunostained placental sections was performed to determine the expression of selected proteins. The morphometric analysis performed for the vascular density-matched placental samples demonstrated a significant increase in the expression of fatty acid translocase (CD36), fatty acid binding proteins (FABP1, FABP4 and FABP5), as well as a decrease in the expression of endothelial lipase (EL) and fatty acid transport protein (FATP4) in the PGDM-complicated pregnancies as compared to the GDMG1 and control groups (p < 0.05). No significant differences with regard to the placental expression of lipoprotein lipase (LPL) and FATP6 protein between GDM/PGDM and non-diabetic patients were noted. Maternal pre-pregnancy weight, body mass index, placental weight as well as the expression of LPL and FABP4 were selected by the linear regression model as the strongest contributors to the fetal birth weight. To conclude, in placentas derived from pregnancies complicated by well-controlled PGDM, the expression of several lipid transporters, including EL, CD36, FATP4, FABP1, FABP4 and FABP5, is altered. Nonetheless, only LPL and FABP4 were significant predictors of the fetal birth weight.

Reproducibility of arterial spin labeling cerebral blood flow image processing: A report of the ISMRM open science initiative for perfusion imaging (OSIPI) and the ASL MRI challenge.

Arterial spin labeling (ASL) is a widely used contrast-free MRI method for assessing cerebral blood flow (CBF). Despite the generally adopted ASL acquisition guidelines, there is still wide variability in ASL analysis. We explored this variability through the ISMRM-OSIPI ASL-MRI Challenge, aiming to establish best practices for more reproducible ASL analysis. Eight teams analyzed the challenge data, which included a high-resolution T1-weighted anatomical image and 10 pseudo-continuous ASL datasets simulated using a digital reference object to generate ground-truth CBF values in normal and pathological states. We compared the accuracy of CBF quantification from each team's analysis to the ground truth across all voxels and within predefined brain regions. Reproducibility of CBF across analysis pipelines was assessed using the intra-class correlation coefficient (ICC), limits of agreement (LOA), and replicability of generating similar CBF estimates from different processing approaches. Absolute errors in CBF estimates compared to ground-truth synthetic data ranged from 18.36 to 48.12 mL/100 g/min. Realistic motion incorporated into three datasets produced the largest absolute error and variability between teams, with the least agreement (ICC and LOA) with ground-truth results. Fifty percent of the submissions were replicated, and one produced three times larger CBF errors (46.59 mL/100 g/min) compared to submitted results. Variability in CBF measurements, influenced by differences in image processing, especially to compensate for motion, highlights the significance of standardizing ASL analysis workflows. We provide a recommendation for ASL processing based on top-performing approaches as a step toward ASL standardization.

Thermal Analysis of a Casson Boundary Layer Flow over a Penetrable Stretching Porous Wedge

This work aims to analyze the Casson thermal boundary layer flow over an expanding wedge in a porous medium with convective boundary conditions and ohmic heating. Moreover, the effects of porosity and viscous dissipation are studied in detail and included in the analysis. The importance of this study is due to its applications in biomedical engineering where the analysis of behavior of non-Newtonian blood flow in arteries and veins is desired. Within the context of blood flow, it is also applicable to many other fields, for instance, radiative therapy, MHD generators, soil machines, melt-spinning, and insulation processes. The modeled problem is a set of PDEs, which is nondimensionalized to derive a nonlinear boundary value problem (BVP). The obtained BVP is solved using the shooting technique, endowed with the order four Runge-Kutta and Newton methods. The impact of different parameters on the momentum and temperature fields is investigated along with two important parameters of physical significance, i.e., the Nusselt number and the surface drag force. Results are validated, and an excellent agreement is seen for the parameters of interest using MATLAB built-in function bvp4c. A significant finding is that by increasing the Casson liquid parameter, the velocity decreases as the wedge expands quicker than the free stream velocity at R=2. However, the velocity increases for the case when R=0.1. A decrease in the Darcy number increases the temperature profile. Furthermore, the convective parameter accelerated the heat transmission rate, and a rise in the Prandtl number thickens the thermal boundary layer. The findings of this investigation contribute to problems in fluid dynamics and heat transfer that involve studying the behavior of a non-Newtonian fluid with Casson rheological properties near a solid porous wedge surface.

MHD flow of the novel quadruple hybrid nanofluid model in a stenosis artery with porous walls and thermal radiation: A Sisko model‐based analysis

AbstractThis study introduces a mathematical model that describes the Magnetohydrodynamics (MHD) flow of blood in a porous stenosis artery, incorporating a new hybrid nanofluid (HNF) model known as ‘Quadruple’ or the tetra‐(HNF) model. An innovative aspect of this study lies in the unexplored combination of tetra‐hybrid nanoparticles with the Sisko rheological model. The conventional Tiwari and Das (HNF) model has been expanded to accommodate the tetra‐(HNFs) case. To transform the governing partial differential equations into ordinary differential equations, a series of variable similarity transformations are employed. The resulting highly nonlinear simultaneous equations are efficiently solved using the shooting method. Numerical computations are conducted to investigate various parametric conditions, and graphs are utilized to visualize notable aspects of flow velocity and temperature. A comprehensive analysis is provided to illustrate the influence of flow parameters on wall shear stress and local Nusselt number, which are depicted through figures and tables. The study shows that the novel tetra‐HNF exhibits enhancements in blood flow when compared to nanofluids with a lower number of hybrids. Increasing the flow power index of non‐Newtonian Sisko model leads to improve convective heat transfer. Furthermore, parameters such as porosity, thermal radiation, and magnetic effects exhibit noticeable impacts on blood flow, temperature, and associated risks in constricted arteries.

TWO PHASE SLIP FLOW OF BLOOD IN HEPATIC ARTERY WITH SPECIAL REFERENCE TO HEPATITIS B

In this paper, we have presented a model of two-phased arterial hepatic blood flow in hepaticarteries remote from the heart and proximate to the Liver keeping in view the nature of hepatic blood circulation in the human body. Blood is supposed to be non-Newtonian of the power-law type. Solutions of the constitutive equations are obtained in analytical as well as in numerical forms. The role of hematocrit is explicit in the determination of blood pressure drop in the case of Hepatic disease Hepatitis B.