START CARE: a protocol for a randomised controlled trial of step-wise budesonide-formoterol reliever-based treatment in children.

Background: Asthma is the most common chronic childhood respiratory condition globally. Inhaled corticosteroid (ICS)-formoterol reliever-based regimens reduce the risk of asthma exacerbations compared with conventional short-acting β-agonist (SABA) reliever-based regimens in adults and adolescents. The current limited evidence for anti-inflammatory reliever therapy in children means it is unknown whether these findings are also applicable to children.

The Anti-Inflammatory Reliever (AIR) Algorithm Study: a protocol for a single-group study of an AIR stepwise approach to the treatment of adult asthma.

Background: The stepwise approach to long-term asthma management, which traditionally incorporates short-acting β-agonist reliever therapy, has been a core feature of asthma guidelines for over 30 years. There have been no studies, however, directly investigating the use of an entire guideline-recommended track. Recently, inhaled corticosteroid-formoterol has been recommended as the preferred reliever therapy in adult asthma, in accordance with a stepwise "Anti-Inflammatory Reliever" (AIR) treatment track.

The Children's Anti-inflammatory Reliever (CARE) study: a protocol for a randomised controlled trial of budesonide-formoterol as sole reliever therapy in children with mild asthma.

Background: Asthma is the most common chronic disease in children, many of whom are managed solely with a short-acting β-agonist (SABA). In adults, the evidence that budesonide-formoterol as sole reliever therapy markedly reduces the risk of severe exacerbations compared with SABA alone has contributed to the Global Initiative for Asthma recommending against SABA monotherapy in this population. The current lack of evidence in children means it is unknown whether these findings are also relevant to this demographic.

How big is your bubble? Characteristics of self-isolating household units ('bubbles') during the COVID-19 Alert Level 4 period in New Zealand: a cross-sectional survey.

Objective: To characterise the self-isolating household units (bubbles) during the COVID-19 Alert Level 4 lockdown in New Zealand.

Design, Setting And Participants: In this cross-sectional study, an online survey was distributed to a convenience sample via Facebook advertising and the Medical Research Institute of New Zealand's social media platforms and mailing list. Respondents were able to share a link to the survey via their own social media platforms and by email.

Budesonide-formoterol reliever therapy versus maintenance budesonide plus terbutaline reliever therapy in adults with mild to moderate asthma (PRACTICAL): a 52-week, open-label, multicentre, superiority, randomised controlled trial.

Background: In adults with mild asthma, a combination of an inhaled corticosteroid with a fast-onset long-acting β-agonist (LABA) used as reliever monotherapy reduces severe exacerbations compared with short-acting β-agonist (SABA) reliever therapy. We investigated the efficacy of combination budesonide-formoterol reliever therapy compared with maintenance budesonide plus as-needed terbutaline.

Methods: We did a 52-week, open-label, parallel-group, multicentre, superiority, randomised controlled trial at 15 primary care or hospital-based clinical trials units and primary care practices in New Zealand.

Refinement of optical imaging spectroscopy algorithms using concurrent BOLD and CBV fMRI.

We describe the use of the three dimensional characteristics of the functional magnetic resonance imaging (fMRI) blood oxygenation level dependent (BOLD) and cerebral blood volume (CBV) MRI signal changes to refine a two dimensional optical imaging spectroscopy (OIS) algorithm. The cortical depth profiles of the BOLD and CBV changes following neural activation were used to parameterise a 5-layer heterogeneous tissue model used in the Monte Carlo simulations (MCS) of light transport through tissue in the OIS analysis algorithm. To transform the fMRI BOLD and CBV measurements into deoxy-haemoglobin (Hbr) profiles we inverted an MCS of extra-vascular MR signal attenuation under the assumption that the extra-/intravascular ratio is 2:1 at a magnetic field strength of 3 T.

Theory and generalization of Monte Carlo models of the BOLD signal source.

The dependency of the blood oxygenation level dependent (BOLD) signal on underlying hemodynamics is not well understood. Building a forward biophysical model of this relationship is important for the quantitative estimation of the hemodynamic changes and neural activity underlying functional magnetic resonance imaging (fMRI) signals. We have developed a general model of the BOLD signal which can model both intra- and extravascular signals for an arbitrary tissue model across a wide range of imaging parameters.

Preservation of visual cortical function following retinal pigment epithelium transplantation in the RCS rat using optical imaging techniques.

The aim of this study was to determine the extent of cortical functional preservation following retinal pigment epithelium (RPE) transplantation in the Royal College of Surgeons (RCS) rat using single-wavelength optical imaging and spectroscopy. The cortical responses to visual stimulation in transplanted rats at 6 months post-transplantation were compared with those from age-matched untreated dystrophic and non-dystrophic rats. Our results show that cortical responses were evoked in non-dystrophic rats to both luminance changes and pattern stimulation, whereas no response was found in untreated dystrophic animals to any of the visual stimuli tested.

Haemodynamic and neural responses to hypercapnia in the awake rat.

The relationship between localized changes in brain activity and metabolism, and the blood oxygenation level-dependent (BOLD) signal used in functional magnetic resonance imaging studies is not fully understood. One source of complexity is that stimulus-elicited changes in the BOLD signal arise both from changes in oxygen consumption due to increases in activity and purely 'haemodynamic' changes such as increases in cerebral blood flow. It is well established that robust cortical haemodynamic changes can be elicited by increasing the concentration of inspired CO(2) (inducing hypercapnia) and it is widely believed that these haemodynamic changes occur without significant effects upon neural activity or cortical metabolism.

Investigating neural-hemodynamic coupling and the hemodynamic response function in the awake rat.

An understanding of the relationship between changes in neural activity and the accompanying hemodynamic response is crucial for accurate interpretation of functional brain imaging data and in particular the blood oxygen level-dependent (BOLD) fMRI signal. Much physiological research investigating this topic uses anesthetized animal preparations, and yet, the effects of anesthesia upon the neural and hemodynamic responses measured in such studies are not well understood. In this study, we electrically stimulated the whisker pad of both awake and urethane anesthetized rats at frequencies of 1-40 Hz.

Concurrent fMRI and optical measures for the investigation of the hemodynamic response function.

Functional magnetic resonance imaging (fMRI) signal variations are based on a combination of changes in cerebral blood flow (CBF) and volume (CBV), and blood oxygenation. We investigated the relationship between these hemodynamic parameters in the rodent barrel cortex by performing fMRI concurrently with laser Doppler flowmetry (LDF) or optical imaging spectroscopy (OIS), following whisker stimulation and hypercapnic challenge. A difference between the positions of the maximum blood oxygenation level-dependent (BOLD) and CBV changes was observed in coronal fMRI maps, with the BOLD region being more superficial.

How visual stimuli activate dopaminergic neurons at short latency.

Unexpected, biologically salient stimuli elicit a short-latency, phasic response in midbrain dopaminergic (DA) neurons. Although this signal is important for reinforcement learning, the information it conveys to forebrain target structures remains uncertain. One way to decode the phasic DA signal would be to determine the perceptual properties of sensory inputs to DA neurons.

Long duration stimuli and nonlinearities in the neural-haemodynamic coupling.

Recent studies have shown that the haemodynamic responses to brief (<2 secs) stimuli can be well characterised as a linear convolution of neural activity with a suitable haemodynamic impulse response. In this paper, we show that the linear convolution model cannot predict measurements of blood flow responses to stimuli of longer duration (>2 secs), regardless of the impulse response function chosen. Modifying the linear convolution scheme to a nonlinear convolution scheme was found to provide a good prediction of the observed data.

Further nonlinearities in neurovascular coupling in rodent barrel cortex.

An essential prerequisite for the accurate interpretation of noninvasive functional brain imaging techniques, such as blood oxygen level dependent (BOLD) fMRI, is a thorough understanding of the coupling relationship between neural activity and the haemodynamic response. The current study investigates this relationship using rat barrel cortex as a model. Neural input was measured by applying current source density (CSD) analysis to multi-laminar field potentials to remove ambiguities regarding the origin of the signal inherent in single electrode recordings.

A model of the dynamic relationship between blood flow and volume changes during brain activation.

The temporal relationship between changes in cerebral blood flow (CBF) and cerebral blood volume (CBV) is important in the biophysical modeling and interpretation of the hemodynamic response to activation, particularly in the context of magnetic resonance imaging and the blood oxygen level-dependent signal. measured the steady state relationship between changes in CBV and CBF after hypercapnic challenge. The relationship CBV is proportional to CBFphi has been used extensively in the literature.

Nonlinear coupling of neural activity and CBF in rodent barrel cortex.

The relationship between neural activity and accompanying changes in cerebral blood flow (CBF) and oxygenation must be fully understood before data from brain imaging techniques can be correctly interpreted. Whether signals in fMRI reflect the neural input or output of an activated region is still unclear. Similarly, quantitative relationships between neural activity and changes in CBF are not well understood.

The hemodynamic impulse response to a single neural event.

This article investigates the relation between stimulus-evoked neural activity and cerebral hemodynamics. Specifically, the hypothesis is tested that hemodynamic responses can be modeled as a linear convolution of experimentally obtained measures of neural activity with a suitable hemodynamic impulse response function. To obtain a range of neural and hemodynamic responses, rat whisker pad was stimulated using brief ( View Article and Find Full Text PDF

Optical imaging spectroscopy in the unanaesthetised rat.

We describe a method for imaging the local cortical haemodynamic response to whisker stimulation in the rat without use of anaesthetic or paralytic agents. Female Hooded Lister rats were anaesthetised and a section of skull overlying somatosensory cortex thinned to translucency. A stainless steel chamber was then secured over the thin cranial window.

A model of the hemodynamic response and oxygen delivery to brain.

A recent nonlinear system by Friston et al. (2000. NeuroImage 12: 466-477) links the changes in BOLD response to changes in neural activity.

Hemodynamic response in the unanesthetized rat: intrinsic optical imaging and spectroscopy of the barrel cortex.

Optical imaging spectroscopy was used to measure the hemodynamic response of somatosensory cortex to stimulation of the whiskers. Responses to brief puffs of air were compared in anesthetized and unanesthetized rats. The hemodynamic response was approximately four times larger in the unanesthetized animal than the corresponding anesthetized animal.