The aim of this study was to investigate the effect of perfusion computed tomography (PCT) with acetazolamide (ACZ) challenge and compare it to 10% carbon dioxide (CO(2)) challenge in rat C6 glioma. PCT was performed on 32 rats, including 20 with orthotopically implanted C6 gliomas and 12 serving as controls. ...

Devices that continuously measure relative blood volume (RBV) changes during hemodialysis (HD) are increasingly used for the prevention of dialysis hypotension and fine-tuning of dry weight. However, RBV measurements are subject to various limitations. First, RBV devices provide information on relative blood volume changes but not on absolute blood volume. ...

As blood circulates through the arterial tree, the flow and pressure pulse distort. Principal factors to this distortion are reflections form arterial bifurcations and the viscous character of the flow of the blood. Both of them are expounded in the literature and included in our analysis. The nonlinearities of inertial ...

BACKGROUND & AIMS: Mammillary body atrophy in alcoholic liver disease usually indicates thiamine deficiency. The purpose of this study was to explore the relationship among blood thiamine, mammillary bodies, major fiber bundle fractional anisotropy, and volume changes with diffusion tensor tractography in patients with acute and acute-on-chronic liver failure of ...

Although a multitude of factors that influence skeletal muscle blood flow have been extensively investigated, the influence of muscle length on limb blood flow has received little attention. Thus, the purpose of this investigation was to determine if cyclic changes in muscle length influence resting blood flow. Nine healthy males ...

This study describes a novel method for measuring relative changes in venous cerebral blood volume (CBVv) using hyperoxia as a contrast agent. This method exploits the extravascular BOLD effect and its dependency on both task-related activation induced changes in venous blood oxygenation and changes due to breathing an oxygen enriched ...

The mechanisms that explain intra-aortic balloon pumping (IABP) effects are not completely understood, and attributing them only to pressure-associated changes in cardiac function would be an oversimplification. Since IABP modifies the aortic and systemic blood-flow pattern, flow-related effects could be expected. To characterize effects of acute heart failure (AHF) on ...

Purpose. To study the short-term effects of intravitreal bevacizumab (Avastin) on retinal blood flow velocity and compare them to clinical outcomes assessed by optical coherence tomography (OCT) and tests of visual acuity. Methods. The Retinal Function Imager (RFI) was used noninvasively and quantitatively to measure retinal blood flow velocity. Eight ...

Motor stimulaton induces a neurovascular response that can be detected by continuous measurement of cerebral blood flow (CBF). Simultaneous changes in arterial blood pressure (ABP) and PaCO(2) have been reported but their influence on the CBF response has not been quantified. Continuous bilateral recordings of CBF velocity (CBFV), ABP and ...

PURPOSE: Lamotrigine (LTG) is an anti epileptic medication (AEM) for which blood levels are helpful for optimal dosing. In late 2010, patients attending an epilepsy clinic were becoming toxic without obvious cause. This paper reports altered levels without change in regimen and provides unexpected findings. METHODS: Patients with elevated LTG ...

BACKGROUND:: Brachial plexus block (BPB) causes vasodilatation and an increase in blood flow to the ipsilateral upper limb. However, no reports have comprehensively evaluated the regional hemodynamic changes after a BPB. METHODS:: Eight healthy adult patients who were scheduled for elective hand surgery had an ultrasound-guided axillary BPB for anesthesia. ...

OBJECTIVE.-: Hemodynamic changes in response to the hypoxic environment of high altitude are vascular bed-specific. The aim of the present study was to investigate diameter and blood flow changes in conduit vessels in response to hypobaric hypoxia. METHODS.-: Eleven healthy subjects ascending Mount Everest to base camp participated in this ...

BackgroundCerebral autoregulation can be impaired after ischemic stroke, with potential adverse effects on cerebral blood flow during early rehabilitation.ObjectiveThe objective of this study was to assess changes in cerebral blood flow velocity with orthostatic variation at 24 hours after stroke.DesignThis investigation was an observational study comparing mean flow velocities (MFVs) ...

AIM: The objective was to characterize the effects of Valsalva maneuver (VM) on the amplitude of cerebrovascular pulsation (CVP), and to explore the direct interactions between the cerebral vasculature and the cerebrospinal fluid compartment in VMIII. METHODS: Twenty-nine healthy volunteers between the ages of 25 and 40 (29.3±SE 4.0) were ...

Obstructive Sleep Apnea (OSA) is one of the most common sleep disordered breathing which affects about 15 % of US adult population. OSA is considered to be an important risk factor for the development of cardiac dysfunction and stroke. In this paper, we present the initial results of our investigation ...

Flow-mediated dilatation (FMD) is the most accepted technique for the evaluation of endothelial function. However, it has been show a great inter-subject variability limiting its clinical use. Carotid-radial pulse wave velocity (PWVcr) was proposed as an alternative tool for the evaluation of endothelial function. At the present, there is no ...

Labor efficiency is desirable in mobile blood collection. There are few published data on labor efficiency. The variability in the labor efficiency of mobile whole blood collections was analyzed. We determined to improve our labor efficiency using lean manufacturing principles. Workflow changes in mobile collections were implemented with the goal ...

Papaverine has been associated with transient cranial nerve dysfunction after topical application during craniotomy. The authors report similar dysfunction after the use of papaverine affected brainstem structures. Two patients undergoing craniotomy for clipping of an aneurysm experienced bilateral depression of cortical somatosensory evoked potentials to both median and tibial nerve ...

BACKGROUND: We attempt to evaluate objectively the regional cerebral blood flow (rCBF) changes during long-term donepezil therapy and the relationship between the clinical response and rCBF change in patients with Alzheimer's disease (AD). PATIENTS AND METHODS: Thirty-one patients with mild-to-moderate AD (11 men, 20 female; mean age, 76.2 ± 6.7 ...

Background: Tilting only the head influences cerebral haemodynamics in term and preterm neonates. Objective: To evaluate near-infrared spectroscopy (NIRS) as a method to detect changes of cerebral oxygenated (HbO(2)) and deoxygenated haemoglobin (Hb) and 'cerebral tissue-oxygenation-index' (cTOI) while tilting. Furthermore to investigate whether the comparison of cTOI and 'cerebral mixed ...

Calibrated blood oxygenation level dependent (BOLD) imaging, a technique used to measure changes in cerebral O(2) metabolism, depends on an accurate model of how the BOLD signal is affected by the mismatch between cerebral blood flow (CBF) and cerebral metabolic rate of O(2) (CMRO(2)). However, other factors such as the ...

We simultaneously measure the flow rate and the normal force on the base, near the outlet, during the discharge through an orifice of a dense packing of monosized disks driven by a conveyor belt. We find that the normal force on the base decreases even when a constant flow rate ...

AIM: This study was performed: 1) to assess the relationship between blood flow velocity in the internal carotid artery (CBF(ICA)) and pial artery pulsation (cc-TQ) and 2) to evaluate flow-induced changes in pial artery compliance. METHODS: Experiments were performed on 10 crossbred male rabbits. Heart rate (HR), blood pressure (BP), ...

1. Intrarenal oxygen availability is the balance between supply, mainly dependent on renal blood flow, and demand, determined by the basal metabolic demand and the energy-requiring tubular electrolyte transport. Renal blood flow is maintained within close limits in order to sustain stable glomerular filtration, so increased intrarenal oxygen consumption is ...

Axillary arterio-arterial graft interposition has been described as a reasonable haemodialysis access in selected patients. In a patient with this unusual access, we measured and calculated effective clearance at different extracorporeal blood flows (Q(b)). Effective clearance increased with increasing blood flow and reached a maximum at a Q(b) of ∼200 ...

OBJECTIVES AND BACKGROUND: The build-up of thromboses in vena cava filters after deployment presents serious problem to the patients. We proposed a novel way to overcome this problem in a belief that intentionally induced swirling flow can optimize blood flow patterns in Vena cava filters, enhance the stirring motion of ...

Sepsis is a leading cause of acute kidney injury (AKI) and mortality in children. Understanding the development of pediatric sepsis and its effects on the kidney are critical in uncovering new therapies. The goal of this study was to characterize the development of sepsis-induced AKI in the clinically relevant cecal ...

The flow of nematic liquid crystals in tightly confined systems was simulated using a molecular theory and an unsymmetric radial basis function collocation approach. When a nematic liquid crystal is subjected to a cavity flow, we find that moderate flows facilitate the relaxation of the system to the stable defect ...

PURPOSE: For the quantification of cardiac (123)I-metaiodobenzylguanidine (MIBG) uptake, the mediastinum is commonly used as a reference region reflecting nonspecific background activity. However, variations in the quantity of vascular structures in the mediastinum and the rate of renal clearance of (123)I-MIBG from the blood pool may contribute to increased interindividual ...

To assess blood flow velocities and spatial distribution of aortic Reynolds numbers in vivo using flow-sensitive magnetic resonance imaging (MRI) and probe for flow instabilities along the aorta based on an empirical model for physiological pulsatile blood flow. Thirty young healthy volunteers were examined by flow-sensitive MRI at eight imaging ...

In the current issue, Chen and co-authors present a mathematical model to simulate shear stress-dependent nitric oxide (NO) transport in a small reconstructed microvascular network. Here their results are discussed in the context of NO-dependent blood flow control. Furthermore, other NO-dependent blood flow control mechanisms are briefly reviewed.

PURPOSE: The objective of this study was to appraise the safety profiles of HES preparations and to find out which HES preparation was the most acceptable in cardiovascular surgery through a comparison with control solutions. METHODS: Pertinent randomized controlled trials were selected through a search of Pubmed, Embase, and Cochrane ...

To understand how arterial-to-venous (AV) oxygen shunting influences kidney oxygenation, a mathematical model of oxygen transport in the renal cortex was created. The model consists of a multiscale hierarchy of eleven counter-current systems representing the various branch levels of the cortical vasculature. At each level equations describing the reactive-advection-diffusion of ...

Objective: To determine the triggers of blood transfusion in patients undergoing percutaneous nephrolithotomy (PCNL). Study Design: Observational study. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from 1988 to 2007.Methodology: The percutaneous surgery database was retrospectively reviewed to identify patients with postoperative haemorrhage and need for blood ...

Vascular-space-occupancy (VASO) MRI, a blood nulling approach for assessing changes in cerebral blood volume (CBV), is hampered by low signal-to-noise ratio (SNR) because only 10-20% of tissue signal is recovered when using nonselective inversion for blood nulling. A new approach, called inflow-VASO (iVASO), is introduced in which only blood flowing ...

Urinary flow is not constant but in fact highly variable, altering the mechanical forces (shear stress, stretch and pressure) exerted on the epithelial cells of the nephron as well as solute delivery. Nitric oxide (NO) and superoxide (O(2)(-)) play important roles in various processes within the kidney. Reductions in NO ...

Otoliths, which are connected to stereociliary bundles in the inner ear, serve as inertial sensors for balance. In teleostei, otolith development is critically dependent on flow forces generated by beating cilia; however, the mechanism by which flow controls otolith formation remains unclear. Here, we have developed a noninvasive flow probe ...

Assembly and alignment of nanowires or nanotubes are critical steps for integrating functional nanodevices by the bottom-up strategy. However, it is still challenging to manipulate either an array of nanowires or individual nanowires in a controllable manner. Here we present a simple but versatile method of positioning and aligning nanowires ...

This paper reports an investigation into the flow behaviour of a biofluid in a microchannel systems through conceptual analysis and modelling. The application is the design of a microfluidic chip developed for the separation of plasma from blood. The effect of key design features of the microchannels on the flow ...

Continuous renal replacement therapy (CRRT) allows gradual, precise removal of excess fluid and solutes. Special considerations are necessary for children who require CRRT because of their smaller circulating blood volumes and the potential for hemodynamic instability associated with the initiation of CRRT. In critically ill children, the CRRT circuit is ...

To better understand what makes the kidney susceptible to tissue hypoxia, we compared, in the rabbit kidney and hind-limb, the ability of feedback mechanisms governing oxygen consumption (VO(2)) and oxygen delivery (DO(2)) to attenuate tissue hypoxia during hypoxemia. In the kidney (cortex and medulla) and hind-limb (biceps femoris muscle), we ...

BACKGROUND: Low-level lead exposure is widespread and has been implicated as a chronic kidney disease (CKD) risk factor. However, studies evaluating associations of lead dose with newer, potentially more accurate, estimates of kidney function, in participants with a wide range of glomerular filtration rates (GFRs), are scarce. METHODS: We compared ...

Cross-streamline migration of deformable entities is essential in many problems such as industrial particulate flows, DNA sorting, and blood rheology. Using two-dimensional numerical experiments, we have discovered that vesicles suspended in a flow with curved flow lines migrate towards regions of high flowline curvature, which are regions of high shear ...

Red blood cell (RBC) flow properties (FPs), specifically their deformability, aggregability, and adherence to endothelial cells, play major roles in blood circulation. Their impairment, as occurs under various blood banking conditions, may contribute to circulatory impairment in recipients. Recent studies and meta-analyses show that the transfusion of stored RBCs (stRBCs) ...

Adaptive Optics Scanning Laser Ophthalmoscopy was used to noninvasively acquire videos of single-file flow through live human retinal parafoveal capillaries. Videos were analyzed offline to investigate capillary flow dynamics. Certain capillaries accounted for a clear majority of leukocyte traffic (Leukocyte-Preferred-Paths, LPPs), while other capillaries primarily featured plasma gap flow (Plasma-Gap-Capillaries, ...

Changes in the arterial partial pressure of CO(2) (PaCO(2)) has a direct though transient effect on the cerebral vasculature and cerebral circulation. Decreased PaCO(2) levels lead to vasoconstriction and can result in dangerously low levels of cerebral perfusion that resolve in 4-6 h. It is currently believed that perfusion abnormalities ...

The hemodynamic, metabolic, and biochemical changes produced during the transition from fetal to neonatal life may be aggravated if an episode of asphyxia occurs during fetal life. The aim of the study was to examine regional cerebral blood flow (RCBF), histological changes, and cerebral brain metabolism in preterm lambs, and ...

In this paper, we present methods for 3D visualization and quantitative measurements of retinal blood flow in rats by the use of optical microangiography imaging technique (OMAG). We use ultrahigh sensitive OMAG to provide high-quality 3D RBF perfusion maps in the rat eye, from which the Doppler angle, as well ...

Measurements of task-induced changes in cerebral blood volume (CBV) have been demonstrated using VAscular Space Occupancy (VASO) techniques (noninvasive and newly developed) and a contrast agent-based (Gd- DTPA) method (invasive but well-established) with functional magnetic resonance imaging (fMRI). We compared the two methods in determining CBV changes during multi-frequency visual ...

Mechanical loading induces positive changes in the skeleton due to direct effects on bone cells, which may include regulation of transcription factors that support osteoblast differentiation and function. Flow effects on osteoblast transcription factors have generally been evaluated after short exposures. In this work, we assayed flow effects on osteogenic ...