Effect of insulin on indices of cerebral blood flow and cerebrovascular compliance in young adults.

Insulin has important vasodilatory effects in the peripheral circulation, but less is known about insulin's role in cerebrovascular control. Herein, we hypothesized both systemic (intravenous) and local (intranasal) insulin administration would increase indices of cerebral blood flow and reduce cerebrovascular compliance (Ci) in young adults. Participants were assigned to one of four separate protocols.

Impact of dietary supplementation of glycocalyx precursors on vascular function in type 2 diabetes.

Degradation of the endothelial glycocalyx in type 2 diabetes (T2D) is thought to contribute to impaired shear stress mechanotransduction, leading to endothelial dysfunction and the development of cardiovascular disease. Herein, we tested the hypothesis that restoration of the endothelial glycocalyx with dietary supplementation of glycocalyx precursors (DSGPs, containing glucosamine sulfate, fucoidan, superoxide dismutase, and high-molecular weight hyaluronan) improves endothelial function and other indices of vascular function in T2D. First, in db/db mice, we showed that treatment with DSGP (100 mg/kg/day) for 4 wk restored endothelial glycocalyx length, as assessed via atomic force microscopy in aortic explants.

Effect of acute intranasal insulin administration on muscle sympathetic nerve activity in healthy young adults.

Systemic insulin increases muscle sympathetic nerve activity (MSNA) via both central actions within the brainstem and peripheral activation of the arterial baroreflex. Augmented MSNA during hyperinsulinemia likely restrains peripheral vasodilation and contributes to the maintenance of blood pressure (BP). However, in the absence of insulin action within the peripheral vasculature, whether central insulin stimulation increases MSNA and influences peripheral hemodynamics in humans remains unknown.

Gap analysis of diabetes-related foot disease management systems in Pacific Islands Countries and Territories.

Background: Pacific Island Countries and Territories (PICTs) are known to have high prevalence of Diabetes Mellitus and high incidence of diabetes-related foot disease. Diabetes-related foot disease can lead to lower limb amputation and is associated with poor outcomes, with increased morbidity and mortality. The purpose of this study was to gain a better understanding of diabetes-related foot disease management in selected countries in PICTs and to identify potential barriers in management of diabetes-related foot disease management in the region.

A qualitative exploration of the experiences of Aboriginal and Torres Strait Islander people using a real-time video-based telehealth service for diabetes-related foot disease.

Introduction: Diabetes-related foot disease (DFD) is one of the most prevalent causes of global hospitalisation and morbidity, and it accounts for up to 75% of lower-extremity amputations globally. The 5-year mortality rate following any amputation ranges from 53% to 100%. Early identification of wounds and multidisciplinary management can reduce amputation rates by 39-56%.

Neuraminidase-induced externalization of phosphatidylserine activates ADAM17 and impairs insulin signaling in endothelial cells.

Endothelial insulin resistance represents a causal factor in the pathogenesis of type 2 diabetes (T2D) and vascular disease, thus the need to identify molecular mechanisms underlying defects in endothelial insulin signaling. We previously have shown that a disintegrin and metalloproteinase-17 (ADAM17) is increased while insulin receptor α-subunit (IRα) is decreased in the vasculature of patients with T2D, leading to impaired insulin-induced vasodilation. We have also demonstrated that ADAM17 sheddase activity targets IRα; however, the mechanisms driving endothelial ADAM17 activity in T2D are largely unknown.

Neuraminidase inhibition improves endothelial function in diabetic mice.

Neuraminidases cleave sialic acids from glycocalyx structures and plasma neuraminidase activity is elevated in type 2 diabetes (T2D). Therefore, we hypothesize circulating neuraminidase degrades the endothelial glycocalyx and diminishes flow-mediated dilation (FMD), whereas its inhibition restores shear mechanosensation and endothelial function in T2D settings. We found that compared with controls, subjects with T2D have higher plasma neuraminidase activity, reduced plasma nitrite concentrations, and diminished FMD.

Home-based exercise improves subclinical atherosclerosis marker in multiple sclerosis.

Purpose: Using a 12-week, randomized controlled trial coupled with social cognitive theory behavioral coaching, we aimed to assess the effect of a home-based aerobic training intervention versus an attention-control on aerobic fitness, subclinical atherosclerosis, and mobility in persons with MS.

Methods: Persons with MS with an expanded disability status scale score between 0 and 4 were randomized to a 12-week aerobic exercise (EX) (n = 26; 19 females; 49 yrs; 28.8 kg/m) or attention-control (CON) condition (stretching; n = 22; 16 females; 44 yrs; 29.

The experiences of health workers using telehealth services for diabetes-related foot complications: a qualitative exploration.

Background: Diabetes-related foot disease (DFD) accounts for up to 75% of lower-extremity amputations globally. Rural and remote communities are disproportionately affected by DFD. Telehealth has been advocated as a strategy to improve equity of access to health care in rural and remote communities.

Impact of sex and diet-induced weight loss on vascular insulin sensitivity in type 2 diabetes.

Vascular insulin resistance, a major characteristic of obesity and type 2 diabetes (T2D), manifests with blunting of insulin-induced vasodilation. Although there is evidence that females are more whole body insulin sensitive than males in the healthy state, whether sex differences exist in vascular insulin sensitivity is unclear. Also uncertain is whether weight loss can reestablish vascular insulin sensitivity in T2D.

Role of adropin in arterial stiffening associated with obesity and type 2 diabetes.

Adropin is a peptide largely secreted by the liver and known to regulate energy homeostasis; however, it also exerts cardiovascular effects. Herein, we tested the hypothesis that low circulating levels of adropin in obesity and type 2 diabetes (T2D) contribute to arterial stiffening. In support of this hypothesis, we report that obesity and T2D are associated with reduced levels of adropin (in liver and plasma) and increased arterial stiffness in mice and humans.

Young Women Are Protected Against Vascular Insulin Resistance Induced by Adoption of an Obesogenic Lifestyle.

Vascular insulin resistance is a feature of obesity and type 2 diabetes that contributes to the genesis of vascular disease and glycemic dysregulation. Data from preclinical models indicate that vascular insulin resistance is an early event in the disease course, preceding the development of insulin resistance in metabolically active tissues. Whether this is translatable to humans requires further investigation.

The shifting care and outcomes for patients with endangered limbs - Critical limb ischemia (SCOPE-CLI) registry overview of study design and rationale.

Background: Critical limb ischemia (CLI), the most severe form of peripheral artery disease, is associated with pain, poor wound healing, high rates of amputation, and mortality (>20% at 1 year). Little is known about the processes of care, patients' preferences, or outcomes, as seen from patients' perspectives. The SCOPE-CLI study was co-designed with patients to holistically document patient characteristics, treatment preferences, patterns of care, and patient-centered outcomes for CLI.

Role of the arterial baroreflex in the sympathetic response to hyperinsulinemia in adult humans.

Muscle sympathetic nerve activity (MSNA) increases during hyperinsulinemia, primarily attributed to central nervous system effects. Whether peripheral vasodilation induced by insulin further contributes to increased MSNA via arterial baroreflex-mediated mechanisms requires further investigation. Accordingly, we examined baroreflex modulation of the MSNA response to hyperinsulinemia.

Anticipation of a midsession reversal in humans.

In a two-stimulus visual discrimination choice task with a reversal in reward contingencies midway through each session, pigeons produce a surprising number of anticipatory errors (i.e., responding to the second-correct stimulus before the reversal) based on failure to inhibit timing-based intrusion errors; limited prior research has suggested humans' performance is qualitatively different.

Living near the edge: How extreme outcomes and their neighbors drive risky choice.

Extreme stimuli are often more salient in perception and memory than moderate stimuli. In risky choice, when people learn the odds and outcomes from experience, the extreme outcomes (best and worst) also stand out. This additional salience leads to more risk-seeking for relative gains than for relative losses-the opposite of what people do when queried in terms of explicit probabilities.

ZENK expression following conspecific and heterospecific playback in the zebra finch auditory forebrain.

Zebra finches (Taeniopygia guttata) are sexually dimorphic songbirds, not only in appearance but also in vocal production: while males produce both calls and songs, females only produce calls. This dimorphism provides a means to contrast the auditory perception of vocalizations produced by songbird species of varying degrees of relatedness in a dimorphic species to that of a monomorphic species, species in which both males and females produce calls and songs (e.g.

Cue integration in spatial search for jointly learned landmarks but not for separately learned landmarks.

The authors investigated how humans use multiple landmarks to locate a goal. Participants searched for a hidden goal location along a line between 2 distinct landmarks on a computer screen. On baseline trials, the location of the landmarks and goal varied, but the distance between each of the landmarks and the goal was held constant, with 1 landmark always closer to the goal.

Discrimination of acoustically similar conspecific and heterospecific vocalizations by black-capped chickadees (Poecile atricapillus).

Chickadees produce a multi-note chick-a-dee call in multiple socially relevant contexts. One component of this call is the D note, which is a low-frequency and acoustically complex note with a harmonic-like structure. In the current study, we tested black-capped chickadees on a between-category operant discrimination task using vocalizations with acoustic structures similar to black-capped chickadee D notes, but produced by various songbird species, in order to examine the role that phylogenetic distance plays in acoustic perception of vocal signals.

Chickadees discriminate contingency reversals presented consistently, but not frequently.

Chickadees are high-metabolism, non-migratory birds, and thus an especially interesting model for studying how animals follow patterns of food availability over time. Here, we studied whether black-capped chickadees (Poecile atricapillus) could learn to reverse their behavior and/or to anticipate changes in reinforcement when the reinforcer contingencies for each stimulus were not stably fixed in time. In Experiment 1, we examined the responses of chickadees on an auditory go/no-go task, with constant reversals in reinforcement contingencies every 120 trials across daily testing intervals.

Pigeons perform poorly on a midsession reversal task without rigid temporal regularity.

Animals make surprising anticipatory and perseverative errors when faced with a midsession reversal of reinforcer contingencies on a choice task with highly predictable stimulus-time relationships. In the current study, we asked whether pigeons would anticipate changes in reinforcement when the reinforcer contingencies for each stimulus were not fixed in time. We compared the responses of pigeons on a simultaneous choice task when the initially correct stimulus was randomized or alternated across sessions.

Avian cognition: examples of sophisticated capabilities in space and song.

Although birds have traditionally and colloquially been considered less cognitively complex than mammals, and especially primates, more recent research has consistently refuted these assumptions. We argue that the impressive abilities of birds to navigate and communicate require considerable information-processing capabilities. These capacities include collecting, organizing, and selecting from a wide variety of navigational cues to orient toward and find a goal location in the spatial domain, and utilizing open-ended categorization and possibly even abstract reasoning to discriminate species-specific acoustic features of songs and calls.

When is a choice not a choice? Pigeons fail to inhibit incorrect responses on a go/no-go midsession reversal task.

In a 2-stimulus visual discrimination choice task with a reversal in reward contingencies midway through each session, pigeons produce a surprising number of both anticipatory errors (i.e., responding to the second-correct stimulus before the reversal) and perseverative errors (i.

Experience affects immediate early gene expression in response to conspecific call notes in black-capped chickadees (Poecile atricapillus).

Black-capped chickadees (Poecile atricapillus) produce numerous vocalizations, including the acoustically complex chick-a-dee call that is composed of A, B, C, and D notes. D notes are longer in duration and lower in frequency than the other note types and contain information regarding flock and species identification. Adult wild-caught black-capped chickadees have been shown to have similar amounts of immediate early gene (IEG) expression following playback of vocalizations with harmonic-like acoustic structure, similar to D notes.