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Introduction: The performance of an oxygenator, as found in literature, is evaluated according to protocols that define standard values of the gas content in the inlet blood. However, when dealing with simulations of lung insufficiency, a more extensive evaluation is needed. This work aims to investigate and assess the gas exchange performance of an oxygenator for different input values of gas content in blood. Methods: Three commercially available oxygenators with different membrane surfaces were investigated in a mock loop for three blood flow rates (0.5l/min, 1l/min, and 5l/min) and two gas-to-blood ratios (1:1, and 15:1). The initial CO2 and O2 partial pressures (pCO2 and pO2) in blood were set to ≥ 100 mmHg and ≤10 mmHg, respectively. For each ratio, the efficiency, defined as the ratio between the difference of pressure inlet and outlet and the inlet pCO2 (pCO2(i)), was calculated. Results: The CO2 elimination in an oxygenator was higher for higher pCO2(i). While for a pCO2(i) of 100 mmHg, an oxygenator eliminated 80 mmHg, the same oxygenator at the same conditions eliminated 5 mmHg CO2 when pCO2(i) was 10 mmHg. The efficiency of the oxygenator decreased from 76,9% to 49,5%. For simulation reasons, the relation between the pCO2(i) and outlet (pCO2(o)) for each oxygenator at different blood and gas flows, was described as an exponential formula. Conclusion: The performance of an oxygenator in terms of CO2 elimination depends not only on the blood and gas flow, but also on the initial pCO2 value. This dependence is crucial for simulation studies in the future. [ABSTRACT FROM AUTHOR]

Hypoxia, a condition when dissolved oxygen (DO) drops down below 2 mg/L1, is one of the most common stressors in aquatic environment. Aquatic animals often overcome this condition with a combination of physiological, behavioural, biochemical and molecular responses. In the present study, we examined the effect of moderate hypoxia on superoxide dismutase (SOD) activity and oxygen transport mechanism in Delminichthys ghetaldii erythrocytes. Popovo minnow (Delminichthys ghetaldii) is an endemic cyprinid fish which inhabits springs and streams in fields Ljubomir, Dabar and Fatnica in B&H, and Bacina lakes in Croatia. During autumn and spring floods, Popovo minnows emerge from the underground waters to surface estavelle. Withdrawal of the water to the underground basins brings them back to their underground habitat. Fishes were collected in the flood plain of Fatnica field (43°00'53''N; 18°19'24''E). Following erythrocyte lineage parameters were measured: number of red blood cells (RBC), hemoglobin concentration, Packed cell volume (PCV), Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin Concentration (MCHC) and MCH (Mean Corpuscular Hemoglobin). Also, the characterization of the SOD from RBC is presented for the first time. Native PAGE resolved the presence of three CuZn SOD isoforms, while isoelectrofocusing revealed the presence of two anionic SOD isoforms with pI 3.4 and 3.5. Exposure to conditions of mild hypoxia induced changes in fish SOD activity, hemoglobin concentration and MCH. Results indicate Delminichthys ghetaldii responds to hypoxia by enhancement of the oxygen carrying capacity and triggering SOD activity. [ABSTRACT FROM AUTHOR]

The article focuses on optimizing sarcopenia screening in older patients with cardiovascular disease (CVD) by evaluating different cut-off values for the SARC-F questionnaire, including the effectiveness of varying SARC-F cut-off scores in detecting sarcopenia.

Methemoglobinemia is a serious hematological disease characterized by the incapability of sufficient oxygen delivery to tissues and cyanosis when iron within hemoglobin in ferrous form (Fe+2) is oxidized to ferric form (Fe+3). Methemoglobinemia may be congenital or acquired. While prilocaine-induced methemoglobinemia can be seen in newborns and early pediatric ages, it is a rare condition in adults. We aimed to investigate prilocaine-induced adult methemoglobinemia with four cases. [ABSTRACT FROM AUTHOR]

Background: Anemia, characterized by low hemoglobin levels, is a global public health concern. Anemia is an independent factor worsening outcomes in various patient groups. Blood transfusion has been the traditional treatment for anemia; its triggers, primarily based on hemoglobin levels; however, hemoglobin level is not always an ideal trigger for blood transfusion. Additionally, blood transfusion worsens clinical outcomes in certain patient groups. This narrative review explores alternative triggers for red blood cell transfusion and their physiological basis. Main Text: The review delves into the physiology of oxygen transport and highlights the limitations of using hemoglobin levels alone as transfusion trigger. The main aim of blood transfusion is to optimize oxygen delivery, necessitating an individualized approach based on clinical signs of anemia and the balance between oxygen delivery and consumption, reflected by the oxygen extraction rate. The narrative review covers different alternative triggers. It presents insights into their diagnostic value and clinical applications, emphasizing the need for personalized transfusion strategies. Conclusion: Anemia and blood transfusion are significant factors affecting patient outcomes. While restrictive transfusion strategies are widely recommended, they may not account for the nuances of specific patient populations. The search for alternative transfusion triggers is essential to tailor transfusion therapy effectively, especially in patients with comorbidities or unique clinical profiles. Investigating alternative triggers not only enhances patient care by identifying more precise indicators but also minimizes transfusion-related risks, optimizes blood product utilization, and ensures availability when needed. Personalized transfusion strategies based on alternative triggers hold the potential to improve outcomes in various clinical scenarios, addressing anemia's complex challenges in healthcare. Further research and evidence are needed to refine these alternative triggers and guide their implementation in clinical practice. [ABSTRACT FROM AUTHOR]

Sex differences in physiological responses to various stressors, including exercise, have been well documented. However, the specific impact of these differences on exposure to hypoxia, both at rest and during exercise, has remained underexplored. Many studies on the physiological responses to hypoxia have either excluded women or included only a limited number without analyzing sex-related differences. To address this gap, this comprehensive review conducted an extensive literature search to examine changes in physiological functions related to oxygen transport and consumption in hypoxic conditions. The review encompasses various aspects, including ventilatory responses, cardiovascular adjustments, hematological alterations, muscle metabolism shifts, and autonomic function modifications. Furthermore, it delves into the influence of sex hormones, which evolve throughout life, encompassing considerations related to the menstrual cycle and menopause. Among these physiological functions, the ventilatory response to exercise emerges as one of the most sex-sensitive factors that may modify reactions to hypoxia. While no significant sex-based differences were observed in cardiac hemodynamic changes during hypoxia, there is evidence of greater vascular reactivity in women, particularly at rest or when combined with exercise. Consequently, a diffusive mechanism appears to be implicated in sex-related variations in responses to hypoxia. Despite well-established sex disparities in hematological parameters, both acute and chronic hematological responses to hypoxia do not seem to differ significantly between sexes. However, it is important to note that these responses are sensitive to fluctuations in sex hormones, and further investigation is needed to elucidate the impact of the menstrual cycle and menopause on physiological responses to hypoxia. [ABSTRACT FROM AUTHOR]

Background. The mechanisms of neurovegetative interaction of the functional reactivity of the oxygen transport system (OTS) and genetically determined typological properties of the central nervous system (CNS) were studied. Material and methods. The typological properties of the central nervous system of elite football players (32 individuals) were determined on the "Diagnost-1" neurodynamic complex. The reactivity of the OTS was investigated in a step-increasing running speed test using the Jaeger Oxycon Mobile gas analyzer. Results. The dependence of the reactive properties of the OTS on the genetically determined functional mobility of nervous processes (FMNP) was established. Statistically significant higher indicators of blood stroke volume, carbon dioxide release rate (VCO2) and blood lactate (HLa) were found in the athletes with a higher level of FMNP than in individuals with a low degree of typological property (p=0.033-0.045). The athletes with low FRNP were characterized by statistically significant high values of heart rate (HR) and rate of oxygen uptake (VO2 max). The indicators of minute volumes of blood and respiration did not show statistically significant differences in groups of sportsmen with different gradations of FMNP (p=0.064-0.078). Conclusions. The theoretical model and mechanisms of interaction of the individual-typological property of FMNP with the functional reactivity of OTS and the possibility of using the results to evaluate the playing activity of football players were discussed. [ABSTRACT FROM AUTHOR]

Cerebral perfusion pressure (CPP) is the net pressure gradient that drives oxygen delivery to cerebral tissue. It is the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP). As CPP is a calculated value, MAP and ICP must be measured simultaneously. In research models, anesthetized and acute monitoring is incapable of providing a realistic picture of the relationship between ICP and MAP under physiological and/or pathophysiological conditions. For long-term monitoring of both pressures, the principle of telemetry can be used. The aim of this study was to map changes in CPP and spontaneous behavior using continuous pressure monitoring and video recording for 7 days under physiological conditions (group C - 8 intact rats) and under altered brain microenvironment induced by brain edema (group WI - 8 rats after water intoxication) and neuroprotection with methylprednisolone - MP (group WI+MP - 8 rats with MP 100 mg/kg b.w. applicated intraperitoneally during WI). The mean CPP values in all three groups were in the range of 40-60 mm Hg. For each group of rats, the percentage of time that the rats spent during the 7 days in movement pattern A (standard movement stereotype) or B (atypical movement) was defined. Even at very low CPP values, the standard movement stereotype (A) clearly dominated over the atypical movement (B) in all rats. There was no significant difference between control and experimental groups. Chronic CPP values with correlated behavioral type may possibly answer the question of whether there is a specific, universal, optimal CPP at all. [ABSTRACT FROM AUTHOR]

Since every biological system requires capillaries to support its oxygenation, design of engineered preclinical models of such systems, for example, vascularized microphysiological systems (vMPS) have gained attention enhancing the physiological relevance of human biology and therapies. But the physiology and function of formed vessels in the vMPS is currently assessed by non‐standardized, user‐dependent, and simple morphological metrics that poorly relate to the fundamental function of oxygenation of organs. Here, a chained neural network is engineered and trained using morphological metrics derived from a diverse set of vMPS representing random combinations of factors that influence the vascular network architecture of a tissue. This machine‐learned algorithm outputs a singular measure, termed as vascular network quality index (VNQI). Cross‐correlation of morphological metrics and VNQI against measured oxygen levels within vMPS revealed that VNQI correlated the most with oxygen measurements. VNQI is sensitive to the determinants of vascular networks and it consistently correlates better to the measured oxygen than morphological metrics alone. Finally, the VNQI is positively associated with the functional outcomes of cell transplantation therapies, shown in the vascularized islet‐chip challenged with hypoxia. Therefore, adoption of this tool will amplify the predictions and enable standardization of organ‐chips, transplant models, and other cell biosystems. [ABSTRACT FROM AUTHOR]

The article focuses on cerebral physiology, covering topics such as cerebral metabolic rate, cerebral circulation, and factors affecting cerebral blood flow. It discusses how various physiological variables such as cerebral autoregulation, neurovascular coupling, and vasomotor reactivity influence cerebral blood flow and oxygen delivery.

The article focuses on the importance of understanding the cardiovascular system's role in delivering oxygen to tissues, with topics including the calculation of oxygen delivery, methods of cardiac output monitoring, and the physical principles behind each technique. It discusses invasive techniques like the Fick principle and thermodilution, minimally invasive techniques such as ultrasound and Doppler, and non-invasive methods like bioimpedance and bioreactance for monitoring cardiac output.

This article provides an overview of the journey of inspired oxygen after its uptake across the alveolar–capillary interface, and the interplay among tissue perfusion, diffusion, and cellular respiration in the transport and utilization of oxygen. The critical interactions between oxygen and its facilitative carriers (hemoglobin in red blood cells and myoglobin in muscle cells), and with other respiratory and vasoactive molecules (carbon dioxide, nitric oxide, and carbon monoxide), are emphasized to illustrate how this versatile system dynamically optimizes regional convective transport and diffusive gas exchange. The rates of reciprocal gas exchange in the lung and the periphery must be well-matched and sufficient for meeting the range of energy demands from rest to maximal stress but not excessive as to become toxic. The mobile red blood cells play a vital role in matching tissue perfusion and gas exchange by dynamically regulating the controlled uptake of oxygen and communicating regional metabolic signals across different organs. Intracellular oxygen diffusion and facilitation via myoglobin into the mitochondria, and utilization via electron transport chain and oxidative phosphorylation, are summarized. Physiological and pathophysiological adaptations are briefly described. Dysfunction of any component across this integrated system affects all other components and elicits corresponding structural and functional adaptation aimed at matching the capacities across the entire system and restoring equilibrium under normal and pathological conditions. [ABSTRACT FROM AUTHOR]

Background: Motivational impairment associated with deficits in processing the anticipation of future reward is hypothesized to be a cardinal feature of schizophrenia spectrum disorders (SZ). Evidence from short-term follow-up (6-week post-treatment) studies suggests that these deficits may improve or be reversed with treatment, although longer-term outcomes are unknown. Here we examined the one-year trajectory of functional activation in brain circuitry associated with reward anticipation in people with recent onset SZ who participated in coordinated specialty care (CSC) treatment, hypothesizing normalization of brain response mirroring previous short-term findings in first-episode individuals. Method: Blood oxygen level-dependent (BOLD) response in the dorsal anterior cingulate cortex, anterior insula, and ventral striatum (VS) associated with reward anticipation during the Incentivized Control Engagement Task (ICE-T) was analyzed in a baseline sample of 49 healthy controls (HCs) and 52 demographically matched people with SZ, with follow-up data available for 35 HCs and 17 people with SZ. Results: In agreement with our hypothesis, significant time × diagnosis interactions were observed across all regions, in which reward anticipation-associated BOLD response increased in SZ to above baseline HC levels at follow-up. Increased VS activation was associated with decreased reality distortion symptoms over the follow-up period. Baseline reward anticipation-associated BOLD response in the right anterior insula was associated with improvement in reality distortion symptoms. Conclusions: These findings suggest that functional deficits in reward anticipation may be reversed after one year of CSC in recent onset participants with SZ, and that this improvement is associated with reduced positive symptoms in the illness. [ABSTRACT FROM AUTHOR]

The article focuses on the efficacy of mechanical ventilation which is determined by the laws of physics related to gas flow. Topics include considered the resistance and compliance are most often referenced and considered the determinants and dynamics thereof are not necessarily understood or considered in and of themselves.

Bubbles are formed as the plunging water jet passes through atmosphere and impinges on the surface of water in the pool, which increases the oxygen level of water. The amount of oxygen transferred into an aeration system can be altered by the flow characteristics of plunging jet. The present study models and simulates the oxygen transfer properties with basic flow characteristics of plunging hollow jets. Variables related to the jet included in this study are jet thickness, jet velocity, jet length, and depth of water. For the estimation of volumetric oxygen transfer coefficient ( K L a), modelling techniques such as multiple nonlinear regression (MNLR), artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), multivariate adaptive regression splines (MARS), and generalized regression neural network (GRNN) are used. The results are presented based on training and testing of the models. A nonlinear relationship proposed for the estimation of K L a is compared with the other soft computing-based approaches. The overall comparison of the results obtained from the application of modelling techniques in estimating the experimental data of plunging hollow jets yielded better prediction accuracy by ANFIS (bell-shaped membership function) as well as ANN as compared to MNLR, MARS, and GRNN. [ABSTRACT FROM AUTHOR]

Iron is an essential micromineral involved in various physiological functions such as oxygen transport. The National Research Council’s Nutrient Requirements of Horses has iron requirements set at 400 mg iron daily for a 500 kg horse at maintenance; however, a survey found that Thoroughbreds consumed well over the daily requirement at 3,900 mg of iron from hay and grain alone. Additionally, a previous study has found a correlation between hyperinsulinemia and increased ferritin, an indicator of iron body stores. Therefore, the objective of the present study was to determine the effects of iron supplementation on body iron stores as well as insulin and glucose dynamics. It was hypothesized that iron supplementation would influence body iron stores and insulin and glucose responses. Mixed-breed geldings [n = 12; 558.9 ± 74.4 kg body weight (BW)] were housed individually for the study. Horses were fed 2% of their BW in grass hay and an iron-free vitamin mineral supplement, consuming an average of 600 mg of iron daily for the first 28 d (Hay Phase). Horses were then assigned to continue on the hay diet (CTRL; n = 4) or an iron-supplemented diet (IRON; n = 8), in which an oral iron supplement was given daily in the form of ferrous sulfate, with IRON horses consuming an average of 4,000 mg of iron daily for 28 d (Supplement Phase). Oral sugar tests (OSTs) were performed at the beginning of the study as well as the end of each phase, using a 0.45 mL/kg of BW Karo Light Syrup dose to determine insulin response, with jugular venous samples taken prior to the dose and 60 min after. All statistical analysis was performed in GraphPadPrism Version 10.2.0 (GraphPad Software, Boston, MA), using analysis of variance for repeated measures and correlation analysis. All OSTs throughout the study had a significant time effect (P < 0.05) for both insulin and glucose. There was a time X treatment trend (P = 0.1) for insulin during the Supplement Phase and when using multiple comparisons, insulin response was significantly greater (P < 0.0007) at 0 versus 60 min in IRON horses. Although there was no correlation found between 60-min insulin and ferritin concentrations in both IRON and CTRL horses, mean ± SD insulin and ferritin in the IRON group were 23.6 ± 10 uU/mL and 570 ± 195.8 ng/mL, respectively, while in the CTRL group these were 12.7 ± 2.9 uU/mL and 453 ± 31.1 ng/mL, respectively. In conclusion, iron supplementation with an inorganic form at 10 times the daily requirement appears to result in increased insulin responses as well as body iron stores. Further research needs to determine if feeds naturally enriched in iron impact glucose metabolism. [ABSTRACT FROM AUTHOR]

• Asymptotic expansion homogenization is used in this study. • Increasing tortuosity decreases capillary conductivity and substrate diffusivity. • Tissue interstitial conductivity is not affected by capillary tortuosity. • Oxygen-glucose is rapidly utilized at proximal tissue during reperfusion process. • Only a small amount of oxygen-glucose can reach to the distal tissue. Brain ischaemia causes reduction of cerebral blood flow, which interrupts the transport of oxygen and glucose to brain tissue. These transport inefficiencies have also been associated with the complex cerebral microvasculature. In this study, the importance of cerebral capillary complexity and tissue interstitial porosity in oxygen and glucose transport and metabolism during brain tissue ischaemia is investigated using an asymptotic expansion homogenization method. Applying this technique produces new macroscale governing equations with associated microscale cell problems. Solving the latter on the brain tissue microstructural geometry will obtain parametric tensors, namely the conductivities of the capillary, K and interstitial space, E ; and the diffusivities of a substrate in the capillary, D M,c , and in interstitial space, D M,t. From the microscale simulations, increasing the capillary tortuosity resulted in a decrement of K and D M,c , but no significant changes in E and D M,t. Meanwhile, increasing the capillary radius resulted in the decrease of all parameters except K . Then, the parametric tensors obtained are used to solve the macroscale governing equations on a one-dimensional brain model under ischaemia-reperfusion conditions. From the macroscale simulations, changing the capillary tortuosity affects the uptake and metabolism of oxygen and glucose during brain ischaemia-reperfusion. In addition, in more tortuous capillaries, oxygen and glucose are utilized rapidly at tissues proximal to the capillary during the reperfusion process, leaving only a small amount of these substrates for distal tissues. This could be associated with severe stroke outcome. It is thus proposed that the capillary tortuosity of a patient could potentially be used as an additional indicator in determining the severity of ischaemic stroke. [ABSTRACT FROM AUTHOR]

We report the fabrication and experimental study of a flexible bi-layer microfluidic device for blood oxygenation, mimicking the thin alveolar exchange barrier constituting a lung. A facile technique is employed to fabricate the device by sandwiching a thin polymeric membrane as the gas exchange layer between two flexible microchannels. A numerical model coupling the mass, momentum, and species transport equations, is used to simulate oxygen diffusion between the blood and oxygen channels across the gas exchange membrane. The oxygen saturation is experimentally measured at different locations in the blood channel along the flow direction and compared against the simulation results, which show a very good agreement. The effect of blood and oxygen flow rates, channel height, and membrane thickness on the variations in oxygen concentration in the blood and oxygen channels and the diffusion membrane are studied. The outcome of the present study may find relevance in the development of organ-on-chip devices for blood oxygenation. [ABSTRACT FROM AUTHOR]

Various imaging techniques have been developed to visualize the three‐dimensional structures of the brain and cerebrovascular vessels. Recently, several imaging techniques have allowed the measurement of cerebral blood flow (CBF) in the whole brain. Despite the rapid development of imaging techniques, numerical methods of predicting CBF are still challenging, due to the complexity of cerebrovascular structure modeling at the clinical level. Additionally, simulation models for oxygen and mass transport from the vasculature to tissues are not available at the clinical level due to the lack of knowledge in the field of microvascular transport. In this study, we propose a computational method to quantify CBF in the whole brain, linking cerebrovascular transport, and brain tissue perfusion. To simplify the linking process, the microvascular transport of blood was treated as a diffusion process. The concentration of CBF was predicted using our novel computational method. Furthermore, we investigated changes in CBF in cases where the blood supply to specific areas of the brain were blocked by disrupted vessels. [ABSTRACT FROM AUTHOR]

In order to fully understand what occurs in microcirculation, it is important to examine how oxygen is transferred to tissues and what factors can affect this process. In this numerical study, the transfer of oxygen through permeable vessel walls from microcirculation to tissue was examined in the presence of an external magnetic field. The blood flow was two-layered with a core region as a particle-fluid suspension and a peripheral cell-free plasma layer being considered. In blood, oxygen was assumed to be transported by convection and molecular diffusion while in the tissue region by molecular diffusion and metabolic consumption. A finite element method was utilized in solving the governing equations. The effects of varying hematocrit, core region thickness, magnetic field strength and wall permeability were investigated. It was observed that as hematocrit, C, increased, PO2 was higher in all three regions. Thus, under conditions where the red blood cell count in the blood is lower than normal, for example in patients with plasma cell dyscrasias or Hb SS-sickle cell, there is less O2 present which can lead to surrounding tissues becoming starved of O2. This can result in twitching, dizziness, nausea, seizures and in severe cases can even be fatal. Another factor which increased O2 is the thickness of the core region. An increase in the core region thickness corresponds to a thinning of the plasma layer. Hence as this peripheral layer thins, the oxygen content elevates in all regions. Increasing the Hartmann number (magnetic field intensity) resulted in a decline in PO2, thus high intensity magnetic fields should be avoided. Furthermore, some drugs administered can alter vessel wall permeability. There was a decrease in PO2 as the vessel walls became more permeable with increasing Darcy number. Therefore, the effect that such drugs will have should be closely monitored. [ABSTRACT FROM AUTHOR]

This paper investigates the spatial-temporal evolution and the transport of the singlet delta oxygen (O2(a1Î"g)) of an atmospheric pressure plasma jet using a 2D fluid modeling. The plasma jet is produced in pure helium or helium with small oxygen admixtures (no bigger than 2%), by applying a constant DC voltage of +5 kV on the annular electrode. It is found that, at the 0.7% O2 admixture, a higher O2(a1Î"g) density is obtained inside the tube before the jet impacts the substrate. After the jet propagates along the substrate surface, the peak O2(a1Î"g) density is transferred from the tube to the gap. Varying the O2 admixtures percentage in the working gas changes the O2(a1Î"g) spatial distribution. The O2(a1Î"g) with two thinner edges is dominantly produced in the heliumâ€"air mixing layer for pure helium. The addition of O2 in the working gas leads to O2(a1Î"g) production in the tube. Meanwhile, the thickness of the O2(a1Î"g) edges increases in the heliumâ€"air mixing layer. But the radius of the O2(a1Î"g) density channel continuously reduces with the O2 admixture. The O2(a1Î"g) density and its surface flux first increase within the 0.7% O2 admixture and then decreases with the further augment of the O2 admixture. The influence of the gas flow velocity on the production and transport of O2(a1Î"g) is also studied. Increasing the gas flow velocity changes the spatial distribution of the O2(a1Î"g) density from the solid structure to the annular structure in the gap. At the same time, lower volume average density and instantaneous flux are obtained at larger gas flow velocity. [ABSTRACT FROM AUTHOR]

The microvasculature plays a key role in oxygen transport in the mammalian brain. Despite the close coupling between cerebral vascular geometry and local oxygen demand, recent experiments have reported that microvascular occlusions can lead to unexpected distant tissue hypoxia and infarction. To better understand the spatial correlation between the hypoxic regions and the occlusion sites, we used both in vivo experiments and in silico simulations to investigate the effects of occlusions in cerebral penetrating arteriole trees on tissue hypoxia. In a rat model of microembolisation, 25 μm microspheres were injected through the carotid artery to occlude penetrating arterioles. In representative models of human cortical columns, the penetrating arterioles were occluded by simulating the transport of microspheres of the same size and the oxygen transport was simulated using a Green's function method. The locations of microspheres and hypoxic regions were segmented, and two novel distance analyses were implemented to study their spatial correlation. The distant hypoxic regions were found to be present in both experiments and simulations, and mainly due to the hypoperfusion in the region downstream of the occlusion site. Furthermore, a reasonable agreement for the spatial correlation between hypoxic regions and occlusion sites is shown between experiments and simulations, which indicates the good applicability of in silico models in understanding the response of cerebral blood flow and oxygen transport to microemboli. Author summary: The brain function depends on the continuous oxygen supply through the bloodstream inside the microvasculature. Occlusions in the microvascular network will disturb the oxygen delivery in the brain and result in hypoxic tissues that can lead to infarction and cognitive dysfunction. To aid in understanding the formation of hypoxic tissues caused by micro-occlusions in the penetrating arteriole trees, we use rodent experiments and simulations of human vascular networks to study the spatial correlations between the hypoxic regions and the occlusion locations. Our results suggest that hypoxic regions can form distally from the occlusion site, which agrees with the previous observations in the rat brain. These distant hypoxic regions are primarily due to the lack of blood flow in the brain tissues downstream of the occlusion. Moreover, a reasonable agreement of the spatial relationship is found between the experiments and the simulations, which indicates the applicability of in silico models to study the effects of microemboli on the brain tissue. [ABSTRACT FROM AUTHOR]

This paper deals with the analysis of the relationship between fetal hemoglobin (HbF) and adult hemoglobin (HbA) in preterm infants as a function of the gestational week and newborn weight based on the available literature. The role of other parameters on the shift and shape of the OHDC curve is also discussed. The function could be useful when dynamic development of OHDC in a neonate occurs in emergencies such as blood transfusions. The main idea is to incorporate the dynamic evolution of the hemoglobin conversion as a mathematical function into existing models of oxygenation in preterm neonates or into automatic feedback control algorithms of oxygenation. This could help further individualize and optimize the oxygenation settings of preterm neonates. [ABSTRACT FROM AUTHOR]

The sample's hemoglobin and glucose levels can be determined by obtaining a blood sample from the human body using a needle and analyzing it. Hemoglobin (HGB) is a critical component of the human body because it transports oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues to the lungs. Calculating the HGB level is a critical step in any blood analysis job. TheHGBlevels often indicate whether a person is anemic or polycythemia vera. Constructing ensemble models by combining two or more base machine learning (ML) models can help create a more improved model. The purpose of this work is to present a weighted average ensemble model for predicting hemoglobin levels. An optimization method is utilized to get the ensemble's optimum weights. The optimum weight for this work is determined using a sine cosine algorithm based on stochastic fractal search (SCSFS). The proposed SCSFS ensemble is compared toDecision Tree, Multilayer perceptron (MLP), Support Vector Regression (SVR) and Random Forest Regressors as model-based approaches and the average ensemble model. The SCSFS results indicate that the proposed model outperforms existing models and provides an almost accurate hemoglobin estimate. [ABSTRACT FROM AUTHOR]

Since COVID-19 was declared as a pandemic by World Health Organization in March 2020, 169,682,828 cases have been reported worldwide, with 151,416,570 recovered, and 3,526,647 deaths by May 28, 2021. Oxygen gas cylinders demand is booming globally due to its need for COVID-19's for intensive care. Thus, it is critical for hospitals to know exactly the time of receiving oxygen gas cylinders since this will help in minimizing the fatality rate. In this regards, this paper proposes a Multilayer Perceptron Neural Network-based model to predict the delivery time of oxygen gas cylinders for a real-life logistics data from a company that delivers oxygen gas cylinders to all cities around Saudi Arabia. Besides, Multilayer Perceptron Neural Network is benchmarked to supported vector machine and multiple linear regression. Although all the considered models have the ability to provide accurate prediction results, the findings indicate that the proposed supported vector machine and Multilayer Perceptron Neural Network model provide better prediction results. The analysis was achieved through a methodology to identify factors with the highest impact and build a neural network model. The model was further optimized to identify the best order and select the best subset of input variables. The analysis showed that the neural network model can be used effectively to estimate the delivery time of oxygen gas cylinders. The model illustrated high accuracy of prediction by comparing the predicted values to the actual values. [ABSTRACT FROM AUTHOR]

There have been few studies in seawater fish of the osmorespiratory compromise, the trade-off between the demands of high permeability of the gills for respiration but low permeability for osmoregulation. Flatfish are of particular interest because of their high tolerance to hypoxia, low metabolic rates, and partial reliance on the skin for O2 uptake (ṀO2). We studied the differential effects of acute challenges in temperature (12 °C to 7 °C, 12 °C to 17 °C), salinity (32 to16), and O2 (> 80% to ~ 10% air saturation) on diffusive water flux and ṀO2 of adult English sole (Parophrys vetulus) and Pacific sanddab (Citharichthys sordidus). Under acclimation conditions (normoxia, 12 °C, 32), the two species exhibited almost identical diffusive water flux rates (~ 0.2 ml/g/h) and ṀO2 (~ 2 µmol/g/h). These values did not depend on the presence or absence of sand in which to bury. Under acute hypoxia (~ 10% saturation), both species exhibited substantial reductions in ṀO2 (by 86–89%) and diffusive water flux (by 32–48%), similar to the osmorespiratory compromise responses of hypoxia-tolerant freshwater fishes. However, the species differed in their sensitivity to acute temperature and salinity challenges. Q10 values for diffusive water flux rates (2.99 overall) were higher than those for ṀO2 (2.06) in the sole, whereas the opposite was true in the sanddab (2.31 versus 3.07). Both species increased diffusive water flux rate (by 26–34%) at salinity 16, but ṀO2 remained unchanged in the sanddab and increased by 19% in the sole, suggesting uncoupling of the two processes. [ABSTRACT FROM AUTHOR]

The paper presents a numerical analysis of the thermal damage process taking place in biological tissue containing a blood vessel during laser irradiation. The internal heat source resulting from laser irradiation based on the solution of the optical diffusion equation is taken into account. The investigation was concerned with the influence of tissue denaturation and oxygen content in blood on temperature distribution. The analysis of oxygen transport to the tissue is treated as a part of the analysis of thermal damage processes. At the stage of numerical computations, the boundary element method and the finite difference method were used. [ABSTRACT FROM AUTHOR]

Objective • The aim of this study was to investigate the effects of different oxygen delivery methods during noninvasive positive-pressure ventilation (NPPV) on transcutaneous oxygen pressure (PtcO2 ), transcutaneous carbon dioxide pressure (PtcCO2 ) and fraction of inspired oxygen (FiO2 ) in order to find more effective oxygen delivery methods. Methods • A total of 20 healthy volunteers participated in this study, all of whom received NPPV. All volunteers received oxygen through a nasal cannula (NC) located in a mask or through a mask alone (OSTM) (oxygen flow rate was 3L/min and 5L/min), PtcO2 and PtcCO2 were measured, and the effects of the 2 methods of oxygen concentration on PtcO2 and PtcCO2 levels were evaluated during noninvasive ventilation. Then, the additional oxygen concentration was stopped, oxygen was delivered through the ventilator, and the oxygen concentration was adjusted so that the PtcO2 reached the same oxygen concentration level as noted through the NC or OSTM. This concentration of oxygen indirectly reflects FiO2 in different oxygen delivery methods. Results • When NPPV was used under the same pressure, FiO2 increased from 44.4% to 65.3% when oxygen was delivered through an NC compared with oxygen supplied by OSTM alone. PtcO2 was also significantly increased from 18.9% to 24.9%; the difference was significant (P<.05), while there was no significant change in PtcCO2 (P>.05). Conclusion • When NPPV is used, an NC can obviously improve FiO2 and PtcO2 without increasing PtcCO2 . It can save oxygen and is more suitable for NPPV during an emergency and for home use. (Altern Ther Health Med. 2022;28(3):24-29). [ABSTRACT FROM AUTHOR]

Flux enhancements of field‐aligned low‐energy O+ ion (FALEO) are simultaneously observed by Arase, Van Allen Probes A and B in the nightside inner magnetosphere during 05–07 UT on September 22, 2018. FALEOs appear after a magnetic dipolarization signature with approximately 6–20 min delay. It has the energy‐dispersion signature from a few keV to ∼100 eV only in the direction parallel to the magnetic field at Arase, while it decreases its energy from a few keV down to 10 eV in both the parallel and antiparallel directions at Probes A and B. We perform a numerical simulation to trace trajectories of test O+ ions in a model magnetosphere, which are launched from above the ionosphere 3–15 min after a substorm. Flying virtual satellites that have the same orbits as the real satellites, we create virtual energy‐time spectrograms of O+ ions to compare with the observed ones. Results show a very good correspondence between them, indicating that FALEOs originate from ionospheric O+ ions that are extracted from the upper ionosphere at substorm onset and flow along the magnetic field toward the geomagnetic equator. It is also revealed that 3–9 hr after their launch, test O+ ions less than 400 eV have a spatial distribution in the inner magnetosphere which is similar to those of the warm plasma cloak and the oxygen torus. We therefore conclude that FALEO is a source of those cold ion populations. Key Points: Flux enhancements of field‐aligned low‐energy O+ ion (FALEO) are simultaneously observed by Arase, Van Allen Probes A and BNumerical simulation well reproduces observed energy‐time spectrograms of FALEO with the energy‐dispersed signature from 1 keV to 10 eVFALEO is a source of the warm plasma cloak and the oxygen torus that appear in the dawn to noon sectors [ABSTRACT FROM AUTHOR]

Hemoglobin, a multi-subunit protein used for oxygen transport to peripheral tissues in animals, has a rich evolutionary history that spans over 500 million years. Repeated use of pre-existing genes has generated novel functions, usually by means of gene duplication events that are followed by co-option. Consequently, the evolution of hemoglobin is a valuable model in understanding the conservative use of extant genetic resources to gradually build metabolic complexity. [ABSTRACT FROM AUTHOR]

Symptomatic pregnant women with coronavirus disease-2019 (COVID-19) are at increased risk of severe disease and death compared with symptomatic nonpregnant females of reproductive age. Among those who become critically ill, profound acute hypoxemic respiratory failure is the dominant finding. Significant morbidity and mortality from COVID-19 are largely due to acute viral pneumonia that evolves to acute respiratory distress syndrome. Admission of these patients with critical disease to an intensive care unit and initiation of invasive mechanical ventilation may be indicated. Effective ventilatory support can be challenging in the COVID-19 patient population, even more so when the need occurs in a woman during pregnancy. Key respiratory changes during pregnancy are reviewed. Principles related to maternal-fetal oxygen transport, assessment of ventilation and oxygenation status, and oxygenation goals are also reviewed. Selected concepts related to mechanical ventilatory support for the woman with COVID-19 and acute respiratory failure during pregnancy are presented including indications for ventilatory support, noninvasive support, and invasive ventilator management. Challenges in providing care to this patient population are identified as well as strategies to address them going forward. [ABSTRACT FROM AUTHOR]

Blood microcirculation supplies neurons with oxygen and nutrients, and contributes to clearing their neurotoxic waste, through a dense capillary network connected to larger tree-like vessels. This complex microvascular architecture results in highly heterogeneous blood flow and travel time distributions, whose origin and consequences on brain pathophysiology are poorly understood. Here, we analyze highly-resolved intracortical blood flow and transport simulations to establish the physical laws governing the macroscopic transport properties in the brain micro-circulation. We show that network-driven anomalous transport leads to the emergence of critical regions, whether hypoxic or with high concentrations of amyloid-β, a waste product centrally involved in Alzheimer's Disease. We develop a Continuous-Time Random Walk theory capturing these dynamics and predicting that such critical regions appear much earlier than anticipated by current empirical models under mild hypoperfusion. These findings provide a framework for understanding and modelling the impact of microvascular dysfunction in brain diseases, including Alzheimer's Disease. Blood microcirculation supplies neurons with oxygen and nutrients, and contributes to clearing their neurotoxic waste. Here, the authors analyse blood flow simulations to establish the physical laws linking the microvascular architecture to the macroscopic transport properties that control oxygen supply and waste clearance. [ABSTRACT FROM AUTHOR]

The placenta is a temporary, multifunctional organ composed of both maternal and fetal components. It maintains homeostasis to ensure the growth of the fetus and well-being of the mother. Abnormalities in placental development have been known to be responsible for several disorders of pregnancy. Conditions coincident with pregnancy can upset the homeostasis and result in critical illness, which can greatly impact placental function and in turn affect the fetus. Decreased blood flow, acidemia, hypercarbia, and hypoxia seen in critically ill pregnant mothers can result in fetal death. Understanding the physiological changes and functioning of the maternal-fetal-placental unit will aid in better management of critically ill mothers. [ABSTRACT FROM AUTHOR]

Oxygen delivery to insect tissues is controlled by transport through a branched tubular network that is connected to the atmosphere by valve-like gates, known as spiracles. In certain physiological regimes, the spiracles appear to be randomly switching between open and closed states. Quantitative analysis of this regime leads a reaction-diffusion problem with stochastically switching boundary condition. We derive an expression for the diffusive flux at long times in this problem. Our approach starts with the derivation of the passage probability for a single particle that diffuses between a stochastically gated boundary, which models the opening and closing spiracle, and the perfectly absorbing boundary, which models oxygen absorption by the tissue. This passage probability is then used to derive an expression giving the diffusive flux as a function of the geometric parameters of the tube and characteristic time scales of diffusion and gate dynamics. [ABSTRACT FROM AUTHOR]

An editorial discusses the challenges of providing safe anesthesia to an aging population in South Africa, emphasizing the impact of aging on physiological parameters and proposing a proactive approach using prophylactic vasoconstrictors after spinal blocks in the elderly.

We recently documented that cardiopulmonary resuscitation (CPR) generates the same level of cardiac output (CO) and mean arterial pressure (MAP) during both normothermia (38 °C) and hypothermia (27 °C). Furthermore, continuous CPR at 27 °C provides O2 delivery (ḊO2) to support aerobic metabolism throughout a 3-h period. The aim of the present study was to investigate the effects of extracorporeal membrane oxygenation (ECMO) rewarming to restore ḊO2 and organ blood flow after prolonged hypothermic cardiac arrest. Eight male pigs were anesthetized and immersion cooled to 27 °C. After induction of hypothermic cardiac arrest, CPR was started and continued for a 3-h period. Thereafter, the animals were rewarmed with ECMO. Organ blood flow was measured using microspheres. After cooling with spontaneous circulation to 27 °C, MAP and CO were initially reduced to 66 and 44% of baseline, respectively. By 15 min after the onset of CPR, there was a further reduction in MAP and CO to 42 and 25% of baseline, respectively, which remained unchanged throughout the rest of 3-h CPR. During CPR, ḊO2 and O2 uptake (V̇O2) fell to critical low levels, but the simultaneous small increase in lactate and a modest reduction in pH, indicated the presence of maintained aerobic metabolism. Rewarming with ECMO restored MAP, CO, ḊO2, and blood flow to the heart and to parts of the brain, whereas flow to kidneys, stomach, liver and spleen remained significantly reduced. CPR for 3-h at 27 °C with sustained lower levels of CO and MAP maintained aerobic metabolism sufficient to support ḊO2. Rewarming with ECMO restores blood flow to the heart and brain, and creates a "shockable" cardiac rhythm. Thus, like continuous CPR, ECMO rewarming plays a crucial role in "the chain of survival" when resuscitating victims of hypothermic cardiac arrest. [ABSTRACT FROM AUTHOR]

Oxygen delivery to the retinal pigment epithelium and the outer retina is essential for metabolism, function, and survival of photoreceptors. Chronically reduced oxygen supply leads to retinal pathologies in patients and causes age-dependent retinal degeneration in mice. Hypoxia can result from decreased levels of inspired oxygen (normobaric hypoxia) or reduced barometric pressure (hypobaric hypoxia). Since the response of retinal cells to chronic normobaric or hypobaric hypoxia is mostly unknown, we examined the effect of six hypoxic conditions on the retinal transcriptome and photoreceptor morphology. Mice were exposed to short- and long-term normobaric hypoxia at 400 m or hypobaric hypoxia at 3450 m above sea level. Longitudinal studies over 11 weeks in normobaric hypoxia revealed four classes of genes that adapted differentially to the hypoxic condition. Seventeen genes were specifically regulated in hypobaric hypoxia and may affect the structural integrity of the retina, resulting in the shortening of photoreceptor segment length detected in various hypoxic groups. This study shows that retinal cells have the capacity to adapt to long-term hypoxia and that consequences of hypobaric hypoxia differ from those of normobaric hypoxia. Our datasets can be used as references to validate and compare retinal disease models associated with hypoxia. [ABSTRACT FROM AUTHOR]

Background: Intestinal ischemia is a common complication with obscure pathophysiology in critically ill patients. Since insufficient delivery of oxygen is discussed, we investigated the influence of oxygen delivery, hemoglobin, arterial oxygen saturation, cardiac index and the systemic vascular resistance index on the development of intestinal ischemia. Furthermore, we evaluated the predictive power of elevated lactate levels for the diagnosis of intestinal ischemia. Methods: In a retrospective case-control study data (mean oxygen delivery, minimum oxygen delivery, systemic vascular resistance index) of critical ill patients from 02/2009–07/2017 were analyzed using a proportional hazard model. General model fit and linearity were tested by likelihood ratio tests. The components of oxygen delivery (hemoglobin, arterial oxygen saturation and cardiac index) were individually tested in models. Results: 59 out of 874 patients developed intestinal ischemia. A mean oxygen delivery less than 250ml/min/m2 (LRT vs. null model: p = 0.018; LRT for non-linearity: p = 0.012) as well as a minimum oxygen delivery less than 400ml/min/m2 (LRT vs null model: p = 0.016; LRT for linearity: p = 0.019) were associated with increased risk of the development of intestinal ischemia. We found no significant influence of hemoglobin, arterial oxygen saturation, cardiac index or systemic vascular resistance index. Receiver operating characteristics analysis for elevated lactate levels, pH, CO2 and central venous saturation was poor with an area under the receiver operating characteristic of 0.5324, 0.52, 0.6017 and 0.6786. Conclusion: There was a significant correlation for mean and minimum oxygen delivery with the incidence of intestinal ischemia for values below 250ml/min/m2 respectively 400ml/min/m2. Neither hemoglobin, arterial oxygen saturation, cardiac index, systemic vascular resistance index nor elevated lactate levels could be identified as individual risk factors. [ABSTRACT FROM AUTHOR]

Iron is essential for cell growth, differentiation, electron transfer, and oxygen transport. Hyperoxia may increase the turnover of bone matrix components with a net effect of accelerated bone growth. Although hyperoxia was claimed could increase osteoblast activity, but expression level in possible genes which play role in proliferation is still unclear. This research aims to prove the differences of expression level of transferrin receptor gene and iron regulated transporter and other genes of 7F2 under 24 h normoxia, 24 h hyperoxia, and 48 h hyperoxia and the effect of hyperoxia by using osteoblast cell culture 7F2. Reverse transcriptase, real time Polymerase Chain Reaction (PCR), and microarray is used to qualitatively detect gene expression. The computer softwares such as National Center for Biotechnology Information (NCBI) data base, Software Affymetrix, DNA Strider program, Genomatix – DiAlign program, Oligo 5.0 program (Software primer design) from Wojciech & Piotr Rychlik, and Genetyx-Mac version 8.0 have been used to analyze the PCR result. Under 24 h hyperoxia, there were 3,884 copies of transferrin receptor mRNA per 1,000,000 copies of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA. After 24 h hyperoxia, 8,325 copies of transferrin receptor mRNA per 1,000,000 GAPDH mRNA copies were found showing 2.1-fold up regulation. After 48 h hyperoxia, there was no significant increase at the level of expression of transferrin receptor mRNA, 8,079 mRNA copies per 1,000,000 copies of mRNA were found (2.0-fold up regulation compared with 24 h normoxia). It can be concluded that hyperoxia might have an effect on upregulating the expression of some osteoblast genes which might have an impact on osteoblast activity. [ABSTRACT FROM AUTHOR]

The weathering front is the boundary beneath Earth's surface where pristine rock is converted into weathered rock. It is the base of the "critical zone", in which the lithosphere, biosphere, and atmosphere interact. Typically, this front is located no more than 20 m deep in granitoid rock in humid climate zones. Its depth and the degree of rock weathering are commonly linked to oxygen transport and fluid flow. By drilling into fractured igneous rock in the semi-arid climate zone of the Coastal Cordillera in Chile we found multiple weathering fronts of which the deepest is 76 m beneath the surface. Rock is weathered to varying degrees, contains core stones, and strongly altered zones featuring intensive iron oxidation and high porosity. Geophysical borehole measurements and chemical weathering indicators reveal more intense weathering where fracturing is extensive, and porosity is higher than in bedrock. Only the top 10 m feature a continuous weathering gradient towards the surface. We suggest that tectonic preconditioning by fracturing provided transport pathways for oxygen to greater depths, inducing porosity by oxidation. Porosity was preserved throughout the weathering process, as secondary minerals were barely formed due to the low fluid flow. [ABSTRACT FROM AUTHOR]

The present work gives insight into the internal heat management of the respiratory system in the terrestrial snail Xeropicta derbentina, which has to cope with extreme climate conditions in its habitat. A realistic model of the lung´s vein system was constructed and the active diffusive surface of capillaries and main vein was calculated and confirmed by geometrical measurements. We here present a model that is able to validate the measured oxygen consumption by the use of the Colburn analogy between mass and momentum transfer. By combining basic diffusion laws with the momentum transfer, i.e. wall shear stress, at the inner wall of the lung capillaries and the main vein, the progression of the oxygen mass fraction in the hemolymph can be visualized. [ABSTRACT FROM AUTHOR]

The relationship between regional variabilities in airflow (ventilation) and blood flow (perfusion) is a critical determinant of gas exchange efficiency in the lungs. Hypoxic pulmonary vasoconstriction is understood to be the primary active regulator of ventilation-perfusion matching, where upstream arterioles constrict to direct blood flow away from areas that have low oxygen supply. However, it is not understood how the integrated action of hypoxic pulmonary vasoconstriction affects oxygen transport at the system level. In this study we develop, and make functional predictions with a multi-scale multi-physics model of ventilation-perfusion matching governed by the mechanism of hypoxic pulmonary vasoconstriction. Our model consists of (a) morphometrically realistic 2D pulmonary vascular networks to the level of large arterioles and venules; (b) a tileable lumped-parameter model of vascular fluid and wall mechanics that accounts for the influence of alveolar pressure; (c) oxygen transport accounting for oxygen bound to hemoglobin and dissolved in plasma; and (d) a novel empirical model of hypoxic pulmonary vasoconstriction. Our model simulations predict that under the artificial test condition of a uniform ventilation distribution (1) hypoxic pulmonary vasoconstriction matches perfusion to ventilation; (2) hypoxic pulmonary vasoconstriction homogenizes regional alveolar-capillary oxygen flux; and (3) hypoxic pulmonary vasoconstriction increases whole-lobe oxygen uptake by improving ventilation-perfusion matching. Author summary: The relationship between regional ventilation (airflow) and perfusion (blood flow) is a major determinant of gas exchange efficiency. Atelactasis and pulmonary vascular occlusive diseases, such as acute pulmonary embolism, are characterized by ventilation-perfusion mismatching and decreased oxygen in the bloodstream. Despite the physiological and medical importance of ventilation-perfusion matching, there are gaps in our knowledge of the regulatory mechanisms that maintain adequate gas exchange under pathological and normal conditions. Hypoxic pulmonary vasoconstriction is understood to be the primary regulator of ventilation-perfusion matching, where upstream arterioles constrict to direct blood flow away from areas that have low oxygen supply, yet it is not understood how this mechanism affects oxygen transport at the system level. In this study we present a computational model of the ventilation-perfusion matching and hypoxic pulmonary vasoconstriction to better understand how physiological regulation at the regional level scales to affect oxygen transport at the system level. Our model simulations predict that this regulatory mechanism improves the spatial overlap of airflow and blood flow, which serves to increase the uptake of oxygen into the bloodstream. This improved understanding of ventilation-perfusion matching may offer insights into the etiology of, and therapeutic interventions for diseases characterized by ventilation-perfusion mismatching. [ABSTRACT FROM AUTHOR]

Purpose: Salusin-β, a multifunctional vasoactive peptide, has a potentially important function in the pathological development of hypertension. However, the exact functional role of salusin-β and the underlying mechanism in this process are still not fully understood. The current study aimed to investigate the effects of silencing salusin-β on vascular function and vascular remodeling, as well as its signaling pathways in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Methods: Silencing salusin-β was performed by caudal vein injection of adenovirus expressing salusin-β short hairpin RNA (shRNA). Acetylcholine (ACh)-induced endothelium-dependent relaxation was used to evaluate vasodilator function, and high K+ solution-induced constriction was used to evaluate vasoconstriction function. Results: Salusin-β levels in plasma and its protein expression in mesenteric artery (MA), coronary artery (CA), and pulmonary artery (PA) of SHR were higher than those in WKY. The salusin-β level and expression were decreased effectively by salusin-β shRNA. Knockdown of salusin-β decreased arterial blood pressure (ABP) and high K+ solution-induced vascular constrictions, and improved the endothelium-dependent relaxation and vascular remodeling in SHR. The improved effect of silencing salusin-β on ACh-induced relaxation in SHR was almost blocked by the nitric oxide synthase (NOS) inhibitor L-NAME. Compared to WKY, the endothelial NOS (eNOS) activity and level, and nitric oxide (NO) level were decreased, while NAD(P)H oxidase activity and reactive oxygen species (ROS) levels in MA, CA, and PA of SHR were increased, which were all redressed by salusin-β knockdown. Conclusion: These results indicate that knockdown of salusin-β improves endothelium-dependent vascular relaxation and vascular remodeling and decreases ABP and vasoconstriction in SHR, which might be accomplished by increasing eNOS activation and NO release while inhibiting NAD(P)H oxidase derived-ROS generation. Scavenging salusin-β improves vascular function and then prevents the development and progression of vasculopathy of hypertension. [ABSTRACT FROM AUTHOR]

A mathematical model of oxygen and carbon dioxide transport via blood in the human body has been formulated. The model is represented by four compartments: alveolar tissue, arterial blood, tissue and venous blood. The aim of this study is to estimate the concentration profiles of oxygen and carbon dioxide over alveolar tissue, arterial blood, tissue and venous blood compartments. The formulation is based on the transport of oxygen from atmospheric air to alveolar tissue and subsequently to capillary bed through inspiration and back flow of carbon dioxide through expiration. Ordinary differential equations and balance law have been employed to formulate compartment-wise transport phenomenon of both oxygen and carbon dioxide in the respiratory tract via blood. The solution of the model has been obtained using eigenvalue approach. The model provide the information regarding absorption rate of oxygen and release rate of carbon dioxide at the respective compartments. The results obtained in this study may help clinical and bio-medical sciences to deal with respiratory ailments faced by the people living at high altitudes. The results are in agreement with those arrived at by N. S. Cherniack et al. (1968). In addition, these results may have utility in biomedical engineering and physiological research problems. [ABSTRACT FROM AUTHOR]

Perfluorocarbons (PFCs) exhibiting high solubility for oxygen are attractive materials as artificial oxygen carriers (AOC), an alternative to whole blood or Haemoglobin-based oxygen carriers (HBOCs). PFC-based AOCs, however, met clinical translation roadblocks due to product quality control challenges. To overcome these issues, we present an adaptation of Quality by Design (QbD) practices to optimization of PFC nanoemulsions (PFC-NEs) as AOCs. QbD elements including quality risk management, design of experiments (DoE), and multivariate data analysis facilitated the identification of composition and process parameters that strongly impacted PFC colloidal stability and oxygen transport function. Resulting quantitative relationships indicated a composition-driven tradeoff between stability and oxygen transport. It was found that PFC content was most predictive of in vitro oxygen release, but the PFC type (perfluoro-15-crown-5-ether, PCE or perfluorooctyl bromide, PFOB) had no effect on oxygen release. Furthermore, we found, under constant processing conditions, all PFC-NEs, comprised of varied PFC and hydrocarbon content, exhibited narrow droplet size range (100–150 nm) and narrow size distribution. Representative PFOB-NE maintained colloidal attributes upon manufacturing on larger scale (100 mL). QbD approach offers unique insights into PFC AOC performance, which will overcome current product development challenges and accelerate clinical translation. [ABSTRACT FROM AUTHOR]