Background:Heat and moisture exchangers (HMEs) are commonly used in chronically tracheostomized spontaneously breathing patients to condition inhaled air maintaining lower airway functions and minimizing viscosity of secretions. Supplemental oxygen flow can be added to most HMEs designed for spontaneously breathing tracheostomized patients.Aim of the Study:To test the efficiency of seven ...

OBJECTIVE:: We investigated the in vitro inspired dose and particle size distribution of albuterol delivered by a vibrating mesh nebulizer through the Vapotherm (Stevensville, MD) humidified high-flow nasal cannula system. DESIGN:: Albuterol (2.5mg/3mL) was delivered by an Aeroneb Solo (Aerogen, Galway, Ireland) nebulizer that was connected via adaptor proximal to ...

During ramp incremental cycling exercise increases in pulmonary O2 uptake (VO2p) are matched by a linear increase in systemic cardiac output (Q). However, it has been suggested that blood flow in the active muscle microvasculature does not display similar linearity in blood flow relative to metabolic demand. This study simultaneously ...

Gas chromatography with mass spectrometric detection (GC-MS) was used to identify and quantify volatile organic compounds in the blood and breath of healthy individuals. Blood and breath volatiles were pre-concentrated using headspace solid phase micro-extraction (HS-SPME) and needle trap devices (NTDs), respectively. The study involved a group of 28 healthy ...

PURPOSE: The purpose of this study was to determine the effects of interstitial pneumonia on pulmonary, systemic, and bronchopulmonary shunt flow. MATERIALS AND METHODS: Phase-contrast flow measurements in the ascending aorta and pulmonary trunk were performed during free breathing and inspiratory breath-holding by use of a 1.5 T MR scanner. The ...

The effect of deep breathing controlled in both rate (0.25, 0.16, 0.1, 0.07, 0.05 and 0.03Hz) and amplitude on the heart rate variability (HRV) and respiration-dependent oscillations of forearm/finger skin blood flow (SBF) has been studied in 29 young healthy volunteers. The influence of sympathovagal balance on the respiratory sinus ...

Cerebral vasomotor reactivity (CVR) represents the capability of cerebral vessels to modify their caliber in response to a stimulus. Impaired CVR is associated with an increased risk for ischemic events in patients with carotid disease. Endothelial dysfunction is considered an important pathogenic factor for atherosclerosis and can be noninvasively assessed ...

Changes in finger tissue blood volume (TBV) measured by light transmission and in laser Doppler flow (LDF) were obtained during long breathing (of 12 s period) and associated with the respiratory phases, inspiration and expiration. For fifteen out of sixteen subjects TBV and LDF started to decrease 0-2 s after ...

Hypocapnia attenuates the sweat response normally seen in hyperthermic resting subjects, but its effect on the blood flow response in their nonglabrous skin under the same hyperthermic conditions remains unclear. In the present study, we investigated whether hypocapnia induced by voluntary hyperventilation affects the blood flow response to heat stress ...

To investigate ocular blood flow and visual function in the Ins2(Akita) diabetic retinopathy mouse model at early and late time points after onset of hyperglycemia. Mice heterozygous for the Ins2(Akita) mutation, which become hyperglycemic at approximately 4 weeks old, were studied at 2.5 and 7.5 months of age, with age-matched ...

BACKGROUND AND OBJECTIVE:The Retinal Function Imager (RFI) (Optical Imaging Ltd., Rehovot, Israel) measures retinal blood flow velocity non-invasively. The authors studied the reproducibility of these measurements and assessed the effect of physiological components on them. PATIENTS AND METHODS:Sixty-seven individuals with no retinal pathology were recruited. Velocity reproducibility was verified by ...

We present a supervised learning based method to estimate a per-pixel confidence for optical flow vectors. Regions of low texture and pixels close to occlusion boundaries are known to be difficult for optical flow algorithms. Using a spatiotemporal feature vector, we estimate if a flow algorithm is likely to fail ...

Optic flow on the retina creates a perception of a person's movement relative to their surroundings. This study investigated the effect of optic flow on perceived exertion during cycling. Fifteen participants completed a 20-km reference cycling time trail in the fastest possible time followed by three randomly counterbalanced 20-km cycling ...

Retinal oximetry of capillaries was performed for early detection of retinal vascular abnormalities, which are caused predominantly by complications of systemic circulatory diseases. As the conventional method for determining absorbance is not applicable to capillaries, multicomponent analysis was used to estimate the absorbance spectra of the retinal blood vessels. In ...

PURPOSE: Our aim was to evaluate the effects of topical carteolol on retinal arterial blood flow (RBF) in patients with primary open-angle glaucoma. METHODS: Sixteen patients received carteolol topically for 90 days. Changes in RBF in the major retinal artery were evaluated using laser Doppler velocimetry at baseline and after 30, ...

The cerebral microvasculature cannot be easily studied non-invasively. Because the retina and brain share embryological, anatomical and physiological similarities, studies of retinal blood vessels may prove to be useful as a surrogate marker for cerebrovascular disease. In epidemiological studies abnormal retinal arteriovenous ratios (AVRs) predict the risk of stroke and ...

The correct segmentation of blood vessels in optical coherence tomography (OCT) images may be an important requirement for the analysis of intra-retinal layer thickness in human retinal diseases. We developed a shape model based procedure for the automatic segmentation of retinal blood vessels in spectral domain (SD)-OCT scans acquired with ...

To investigate the involvement of glial cells in the autoregulation of optic nerve head (ONH) blood flow in response to elevated intraocular pressure (IOP). Rabbit eyes were treated with an intravitreal injection of l-2-aminoadipic acid (LAA), a gliotoxic compound. Twenty-four hours after the injection IOP was artificially elevated from a ...

We present a design for a sheath-flow cuvette that uses a relatively inexpensive quartz cuvette. The cuvette has a high optical quality square flow chamber that is fused to quartz tubes at each end. PEEK/TEFZEL fittings hold and seal the quartz flow chamber without putting strain on the cuvette. The ...

We review the cellular and physiological mechanisms responsible for the regulation of blood flow in the retina and choroid in health and disease. Due to the intrinsic light sensitivity of the retina and the direct visual accessibility of fundus blood vessels, the eye offers unique opportunities for the non-invasive investigation ...

PURPOSE: To investigate with color Doppler imaging the effects of phacoemulsification surgery under topical anesthesia on retrobulbar vessels hemodynamics. METHODS: In this prospective study, color Doppler imaging was used to measure the maximum (Vmax) and minimum flow velocity (Vmin) of the central retinal vein, and the Vmax and Vmin, pulsatility ...

An optical hot-wire flow sensing grid is presented using a single piece of self-heated optical fiber to perform distributed flow measurement. The flow-induced temperature loss profiles along the fiber are interrogated by the in-fiber Rayleigh backscattering, and spatially resolved in millimeter resolution using optical frequency domain reflectometry (OFDR). The flow ...

The Retinal Functional Imager (RFI) is a novel method for assessing retinal blood flow (RBF) velocity. The purpose of this study was to evaluate RBF velocities in normal human retinas using the RFI. RBF velocity measurements were performed in normal subjects using the RFI (Optical Imaging Ltd., Rehovot, Israel) at ...

The aim of this study was to characterize the microvascular flow abnormalities and oxygenation changes that are present following six months of hyperglycemia in the diabetic Ins2(Akita) mouse. Previous studies have shown decreased retinal blood flow in the first several weeks of hyperglycemia in rodents, similar to the decreases seen ...

OBJECTIVE: To investigate the compatibility of recombinant tissue plasminogen activator (rtPA) and bevacizumab in vitro because during surgery, rtPA or rtPA-induced plasmin may cleave and inactivate bevacizumab. METHODS: To simulate the intraoperative range of mixing ratios of rtPA, bevacizumab, and subretinal blood, we calculated the volumes of 12 submacular hemorrhages ...

BACKGROUND: Retinal vessel oxygenation saturation measurements have been the focus of much attention in recent years as a potential diagnostic parameter in a number of ocular and systemic pathologies. This interest has been heightened by the ability to measure oxygen saturation in vivo using a photographic technique. METHODS: Retinal vessel ...

Accurate quantification of circulating cell populations in mice is important in many areas of preclinical biomedical research. Normally, this is done either by extraction and analysis of small blood samples or, more recently, by using microscopy-based in vivo fluorescence flow cytometry. We describe a new technological approach to this problem ...

During high-frequency oscillatory ventilation, bias flow is the continuous flow of gas responsible for replenishing oxygen and removing CO(2) from the patient circuit. Bias flow is usually set at 20 L/min, but many patients require neuromuscular blockade at this flow rate. The need for neuromuscular blockade may be eliminated by ...

This study was carried out to assess the prevalence of mange in sheep and goats in five local government areas (LGAs) of Ogun State in South Western Nigeria. A total of 4,973 sheep and 7,902 goats of West African Dwarf breeds were sampled of which only 4 (0.08%) of sheep ...

Toxicokinetic investigations are an essential component of nonclinical toxicology studies and generally rely on bioanalysis of plasma samples, which requires relatively large volumes of blood and, often, additional numbers of animals. Dried blood spot (DBS) analysis can substantially reduce the volume of blood needed and, therefore, presents a particular opportunity ...

We investigated the effect of localized visual stimulation on human retinal blood velocity using an adaptive optics scanning laser ophthalmoscope (AOSLO). To measure the blood velocity response, the AOSLO scanning raster was moved over the target arteries and red blood cell velocity was measured. Localized visual stimuli were delivered by ...

The retinal arterial network structure can be altered by systemic diseases such as hypertension and diabetes. In order to compare the energy requirement for maintaining retinal blood flow and vessel wall metabolism between normal and hypertensive subjects, 3D hypothetical models of a representative retinal arterial bifurcation were constructed based on ...

Introduction: Aquaporins (AQPs) are membrane proteins that facilitate water and small solute movement in tissues. Hydrocephalus is the major central nervous system disorder associated with defective cerebrospinal fluid turnover. Aquaporin-4 (AQP4) is a water channel located mainly at the blood-brain barrier (BBB) and blood-cerebrospinal fluid (CSF) interfaces and is associated ...

Deformation of a red blood cell (RBC) in bounded two-dimensional Poiseuille flows is studied by using an immersed boundary method (IBM). An elastic spring model is applied to simulate the skeleton structure of a RBC membrane. As a benchmarking test, the dynamical behavior of a single RBC under a simple ...

Single ventricle congenital heart defects are usually palliated with the end result of a Fontan circulation. Despite improving results, this circulation is still associated with long-term failure. We previously developed an animal model of mechanical cavopulmonary circulation support that was successful in the acute and mid-term period. In the current ...

The present experiments were undertaken to evaluate the validity of absolute flow velocity measurements with a dual-beam bidirectional Doppler Fourier-domain optical coherence tomography (FD-OCT) system. The flow velocities of diluted milk through a glass capillary were measured at 30 different preset velocities in the range of 0.9 to 39.3 mm/s ...

The aim of the study was to develop a high-content flow cytometric method for assessing the viability and damage of small, medium, and large retinal ganglion cells (RGCs) in N-methyl-D-aspartic acid (NMDA)-injury model. Retinal toxicity was induced in rats by intravitreal injection of NMDA and RGCs were retrogradely labeled with ...

Nature has provided a vast array of bioactive compounds that have been exploited for either diagnostic or therapeutic use. The field of thrombosis and haemostasis in particular has enjoyed much benefit from compounds derived from nature, notably from snakes and blood-feeding animals. Indeed, the likelihood that blood-feeding animals would harbour ...

BACKGROUND: /st>Microcirculatory and mitochondrial dysfunction are important factors in the development of septic shock. In this study, we investigated the effects of fluid resuscitated endotoxaemic shock and norepinephrine treatment on intestinal microcirculation and mitochondrial function in sheep. METHODS: /st>Eight anaesthetized sheep received an i.v. infusion of endotoxin. After 24 h, ...

A new type of glyph is introduced to visualize unsteady flow with static images, allowing easier analysis of time-dependent phenomena compared to animated visualization. Adopting the visual metaphor of radar displays, this glyph represents flow directions by angles and time by radius in spherical coordinates. Dense seeding of flow radar ...

Sodium nitroprusside-enhanced cardiopulmonary resuscitation consists of active compression-decompression, an impedance threshold device, abdominal binding, and large intravenous doses of sodium nitroprusside. We hypothesize that sodium nitroprusside-enhanced cardiopulmonary resuscitation will significantly increase carotid blood flow and return of spontaneous circulation compared to standard cardiopulmonary resuscitation after prolonged ventricular fibrillation and pulseless ...

BACKGROUND: Despite the morbidity and mortality of subarachnoid hemorrhage (SAH), the average volume of a typical hemorrhage is not well defined. Animal models of SAH often do not accurately mimic the human disease process. OBJECTIVE: The purpose of this study is to estimate the average SAH volume, allowing standardization of ...

Seventy pluriparous high-yielding cows were used to investigate the impact of metabolic traits and body condition score (BCS) during early lactation on subclinical endometritis diagnosed at weeks 5, 6 and 7 postpartum (pp). Blood samples were collected from animals with no peripartum problems from the second (W2) to seventh (W7) ...

Zooplankton in the ocean respond to visual and hydro-mechanical cues such as small-scale shear in turbulent flow. In addition, they form strong aggregations where currents intersect sloping bottoms. Strong and predictable tidal currents over a sill in Knight Inlet, Canada, make it an ideal location to investigate biological behaviour in ...

Pharmacological Magnetic Resonance Imaging (phMRI) methods have significantly expanded the stimulation repertoire available to preclinical fMRI research, by allowing to selectively probe the activity of specific brain circuitries and neurotransmitter systems. However, the application of phMRI to animal models is constrained by a number of experimental factors. Firstly, in order ...

For organisms that fly or swim, movement results from the combined effects of the moving medium - air or water - and the organism's own locomotion. For larger organisms, propulsion contributes significantly to progress but the flow usually still provides significant opposition or assistance, or produces lateral displacement ('drift'). Animals ...

In quantitative measurements of small animal PET studies, blood sampling is limited due to the small amounts of blood such animals can provide. In addition, injection doses are quite limited. In this situation, a high-sensitivity well counter would be useful for reducing the amount of the blood sample needed from ...

Is faster or stronger sniffing important for the olfactory system? Odorant molecules are captured by sniffing. The features of sniffing constrain both the temporality and intensity of the input to the olfactory structures. In this context, it is clear that variations in both the sniff frequency and flow rate have ...

BACKGROUNDUterus transplantation may be the only theoretical option for some women, for example, those with congenital uterine infertility or who have undergone hysterectomy. In this study, we evaluated the intra- and post-operative blood flow conditions of vascular anastomosed regions and the blood-perfused area of the transplanted uterus in a cynomolgus ...

To describe a new method of CPR that optimizes vital organ perfusion pressures and carotid blood flow. We tested the hypothesis that a combination of high dose sodium nitroprusside (SNP) as well as non-invasive devices and techniques known independently to enhance circulation would significantly improve carotid blood flow (CBF) and ...