The role of α-adrenergic mechanisms in sympathetic baroreflex control of human blood pressure.

This study tested the hypothesis that neural and vascular α-adrenergic mechanisms contribute to sympathetic baroreflex regulation of human blood pressure. Muscle sympathetic nerve activity (MSNA; peroneal microneurography) was measured and sympathetic action potentials (APs) were extracted from the filtered MSNA neurogram (continuous wavelet transform) in eight participants (5 females; 28±7 years) during a baseline (BSL) condition and a dexmedetomidine infusion (DEX; α-adrenergic receptor agonist; 10 min loading dose at 0.225 μg/kg; maintenance dose: 0.

Adults with down syndrome exhibit altered somatosensory cortical inhibition.

Down syndrome (DS) is a developmental genetic disorder that is associated with an accelerated aging profile and high probability of early incidence Alzheimer's disease like symptoms. It is well established that there are morphological differences in the brains of adults with DS, but the net impact of the genetic disruption on cortical function remains poorly understood. To address this knowledge gap, we used magnetoencephalographic (MEG) brain imaging to assess the somatosensory cortical activity elicited by a paired-pulse electrical stimulation of the right median nerve of adults with DS (N = 19; Age = 28.

Sex differences in sleep apnea and Alzheimer's Disease: role of cerebrovascular dysfunction.

Obstructive sleep apnea (OSA) significantly impacts cardiovascular health in post-menopausal females. Given that cardiovascular and cerebrovascular diseases are tightly linked, OSA-mediated impacts on cerebrovascular function and Alzheimer's Disease (AD) risk are also likely more manifest in females. This review will: summarize sex differences in cerebrovascular function, review the vascular hypothesis of AD, characterize sex differences in the OSA phenotype and implications for cerebrovascular control, and highlight OSA-mediated AD risk.

Acute exogenous oestradiol augments endothelial and smooth muscle vasodilatory responsiveness in premenopausal but not postmenopausal females.

Menopause is associated with vascular dysfunction. During the menopausal transition, endogenous oestradiol concentrations diminish. Oestradiol is vasoprotective because it has direct and indirect effects on the vasculature.

3D printed optimized electrodes for electrochemical flow reactors.

Recent advances in 3D printing have enabled the manufacture of porous electrodes which cannot be machined using traditional methods. With micron-scale precision, the pore structure of an electrode can now be designed for optimal energy efficiency, and a 3D printed electrode is not limited to a single uniform porosity. As these electrodes scale in size, however, the total number of possible pore designs can be intractable; choosing an appropriate pore distribution manually can be a complex task.

Effect of endothelin-1 on the blood pressure response to acute hypoxia and hyperoxia in healthy young men.

Endothelin-1 (ET-1) and its receptors are linked to increases in sensitivity of the chemoreceptors to hypoxic stress and the development of hypertension in preclinical models. We hypothesized ET receptor antagonism would lower resting blood pressure (BP) as well as the acute BP response to chemoreflex stress. Twenty-four men (31 ± 5 years, 26 ± 3 kg/m) completed two study visits (control, bosentan).

Interaction of simultaneous hypoxia and baroreflex loading on control of sympathetic action potential subpopulations.

Efferent muscle sympathetic nerve activity (MSNA) is under tonic baroreflex control. The arterial baroreflex exerts the strongest influence over medium-sized sympathetic action potential (AP) subpopulations in efferent MSNA recordings. Prior work from multiunit MSNA recordings has shown baroreflex loading selectively abolishes the sympathetic response to hypoxia.

Central α-adrenergic mechanisms regulate human sympathetic neuronal discharge strategies.

The present study investigated the impact of central α-adrenergic mechanisms on sympathetic action potential (AP) discharge, recruitment and latency strategies. We used the microneurographic technique to record muscle sympathetic nerve activity and a continuous wavelet transform to investigate postganglionic sympathetic AP firing during a baseline condition and an infusion of a α-adrenergic receptor agonist, dexmedetomidine (10 min loading infusion of 0.225 µg kg; maintenance infusion of 0.

When Are "Paraphernalia" Critical Medical Supplies?

Evidence of harm reduction interventions' morbidity and mortality benefits is abundant and of high quality, so there are good reasons for regional and national groups to advocate for more widespread distribution of legally regulated "drug paraphernalia," including needles, syringes, and fentanyl test strips. But lack of consistency among states' laws means that patients' interstate travel can subject them to being charged with possession of illegal items. This commentary on a case offers guidance to clinicians looking to help patients understand legal risks of interstate travel with supplies that are prescribed or recommended to reduce harms of their drug use and explores the ethical responsibilities of physicians in jurisdictions that legally prohibit these harm reduction interventions.

Conventional and unconventional T-cell responses contribute to the prediction of clinical outcome and causative bacterial pathogen in sepsis patients.

Sepsis is characterized by a dysfunctional host response to infection culminating in life-threatening organ failure that requires complex patient management and rapid intervention. Timely diagnosis of the underlying cause of sepsis is crucial, and identifying those at risk of complications and death is imperative for triaging treatment and resource allocation. Here, we explored the potential of explainable machine learning models to predict mortality and causative pathogen in sepsis patients.

Rabies experts on demand: A cross-sectional study describing the use of a rabies telehealth service.

Background: Rabies expert on demand (REOD) telehealth service is provided by the U.S. Centers for Disease Control and Prevention (CDC) to assist public health practitioners, health providers, and the public to interpret national and international rabies prevention guidelines.

Quadriceps fatigue during hypoxic and ischemic knee-extension exercise is similar in males and females.

Hypoxia is known to increase muscle fatigue via both central and peripheral mechanisms. Females are typically less fatigable than males during isometric fatiguing contractions due to greater peripheral blood flow. However, sex differences in fatigue are blunted during dynamic fatiguing tasks.

Disruption of Sensorimotor Cortical Oscillations by Visual Interference Predicts the Altered Motor Performance of Persons with Cerebral Palsy.

Emerging evidence indicates that aberrations in sensorimotor cortical oscillations likely play a key role in uncharacteristic motor actions seen in cerebral palsy. This interpretation is largely centered on the assumption that the aberrant cortical oscillations primarily reflect the motor aspects, with less consideration of possible higher-order cognitive connections. To directly probe this view, we examined the impact of cognitive interference on the sensorimotor cortical oscillations seen in persons with cerebral palsy using magnetoencephalography.

Rates Among Hospitalized Patients With COVID-19 Treated With Convalescent Plasma: A Systematic Review and Meta-Analysis.

Objective: To examine the association of COVID-19 convalescent plasma transfusion with mortality and the differences between subgroups in hospitalized patients with COVID-19.

Patients And Methods: On October 26, 2022, a systematic search was performed for clinical studies of COVID-19 convalescent plasma in the literature from January 1, 2020, to October 26, 2022. Randomized clinical trials and matched cohort studies investigating COVID-19 convalescent plasma transfusion compared with standard of care treatment or placebo among hospitalized patients with confirmed COVID-19 were included.

Reduced brainstem volume is associated with mobility impairments in youth with cerebral palsy.

Background: Persons with cerebral palsy (CP) have impaired mobility that has been attributed to changes in structure and function within the nervous system. The brainstem is a region that plays a critical role in mobility by connecting the cortex and cerebellum to the spinal cord, yet this region has been largely unstudied in persons with CP.

Research Question: We used high-resolution structural MRI and biomechanical analyses to examine whether the volume of the whole brainstem and its constituent elements are altered in CP and if these alterations relate to the mobility impairments within this population.

Sex Differences in Neurovascular Control: Implications for Obstructive Sleep Apnea.

Patients with obstructive sleep apnea (OSA) have a heightened risk of developing cardiovascular diseases, namely hypertension. While seminal evidence indicates a causal role for sympathetic nerve activity in the hypertensive phenotype commonly observed in patients with OSA, no studies have investigated potential sex differences in the sympathetic regulation of blood pressure in this population. Supporting this exploration are large-scale observational data, as well as controlled interventional studies in healthy adults, indicating that sleep disruption increases blood pressure to a greater extent in females relative to males.

Tuning Alkaline Anion Exchange Membranes through Crosslinking: A Review of Synthetic Strategies and Property Relationships.

Alkaline anion exchange membranes (AAEMs) are an enabling component for next-generation electrochemical devices, including alkaline fuel cells, water and CO electrolyzers, and flow batteries. While commercial systems, notably fuel cells, have traditionally relied on proton-exchange membranes, hydroxide-ion conducting AAEMs hold promise as a method to reduce cost-per-device by enabling the use of non-platinum group electrodes and cell components. AAEMs have undergone significant material development over the past two decades; however, challenges remain in the areas of durability, water management, high temperature performance, and selectivity.

Attenuated cardiac autonomic function in humans with high-affinity hemoglobin and compensatory polycythemia.

During hypoxic exposure, humans with high-affinity hemoglobin (and compensatory polycythemia) have blunted increases in heart rate compared with healthy humans with typical oxyhemoglobin dissociation curves. This response may be associated with altered autonomic control of heart rate. Our hypothesis-generating study aimed to investigate cardiac baroreflex sensitivity and heart rate variability among nine humans with high-affinity hemoglobin [6 females, O partial pressure at 50% [Formula: see text] (P) = 16 ± 1 mmHg] compared with 12 humans with typical affinity hemoglobin (6 F, P = 26 ± 1 mmHg).

Reduced Brainstem Volume is Associated with Mobility Impairments in Youth with Cerebral Palsy.

Persons with cerebral palsy (CP) have impaired mobility that has been attributed to changes in structure and function within the nervous system. The brainstem is a region that plays a critical role in locomotion by connecting the cortex and cerebellum to the spinal cord, yet this region has been largely unstudied in persons with CP. The objective of this investigation was to use high-resolution structural MRI and biomechanical analyses to examine whether the volume of the whole brainstem and its constituent elements are altered in CP, and if these alterations relate to the mobility impairments within this population.

Reduced wrist flexor H-reflex excitability is linked with increased wrist proprioceptive error in adults with cerebral palsy.

Although most neurophysiological studies of persons with cerebral palsy (CP) have been focused on supraspinal networks, recent evidence points toward the spinal cord as a central contributor to their motor impairments. However, it is unclear if alterations in the spinal pathways are also linked to deficits in the sensory processing observed clinically. This investigation aimed to begin to address this knowledge gap by evaluating the flexor carpi radialis (FCR) H-reflex in adults with CP and neurotypical (NT) controls while at rest and during an isometric wrist flexion task.

Endothelin-1 receptor blockade does not alter the sympathetic and hemodynamic response to acute intermittent hypoxia in men.

Repeat exposures to low oxygen (intermittent hypoxia, IH), like that observed in sleep apnea, elicit increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP) in men. Endothelin (ET) receptor antagonists can attenuate the sympathetic and BP response to IH in rodents; whether these data translate to humans are unclear. We hypothesized that ET-receptor antagonism would ameliorate any rise in MSNA and BP following acute IH in humans.