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Following on from the COVID-19 pandemic is another worldwide public health challenge that is referred to variously as long COVID, post-COVID syndrome or post-acute sequelae of SARS-CoV-2 infection (PASC). PASC comes in many forms and affects all body organs. This heterogeneous presentation suggests involvement of the autonomic nervous system (ANS), which has numerous roles in the maintenance of homeostasis and coordination of responses to various stressors. Thus far, studies of ANS dysregulation in people with PASC have been largely observational and descriptive, based on symptom inventories or objective but indirect measures of cardiovascular function, and have paid little attention to the adrenomedullary, hormonal and enteric nervous components of the ANS. Such investigations do not consider the syndromic nature of autonomic dysfunction. This Review provides an update on the literature relating to ANS abnormalities in people with post-COVID syndrome and presents a theoretical perspective on how the ANS might participate in common features of PASC. Autonomic nervous system dysregulation contributes to the chronic, debilitating disorders referred to as 'long COVID' or post-acute sequelae of SARS-CoV-2 infection (PASC). Here, Goldstein describes a multisystem, multidisciplinary approach to understanding PASC-induced alterations in feedback-regulated, plastic networks that determine homeostasis and allostasis. Key points: The diverse nature of post-COVID syndrome suggests involvement of the autonomic nervous system (ANS), which plays numerous roles in homeostasis and coordinates responses to essentially all stressors. The ANS concept was promulgated before the discoveries of neuroendocrine systems, immune and inflammatory systems, and the central autonomic network; the extended autonomic system theory is a necessary update. Publications on post-COVID dysautonomias have not considered the syndromic nature of autonomic dysfunctions. Such studies have been largely observational and descriptive, based on symptom inventories or objective but indirect cardiovascular measures; the hormonal and enteric components of the ANS have generally been ignored. Understanding of multisystem disorders of regulation, such as post-COVID syndrome, requires a shift towards consideration of the feedback-regulated, plastic networks that, via the extended autonomic system, determine homeostasis and allostasis. [ABSTRACT FROM AUTHOR]

We describe a patient with neurogenic orthostatic hypotension (nOH) after brainstem neurosurgery in whom baroreflex-cardiovagal function was normal despite baroreflex-sympathoneural failure. We also cite other conditions entailing differential alterations in the two efferent limbs of the baroreflex. Any condition involving nOH from selective loss of sympathetic noradrenergic innervation, interference with sympathetic pre-ganglionic transmission in the thoracolumbar spinal cord, sympathectomies, or attenuated intra-neuronal synthesis, storage, or release of norepinephrine would be expected to manifest with selective baroreflex-sympathoneural dysfunction. We advise caution in relying on indices of baroreflex-cardiovagal function for diagnosing nOH, since normal values for these indices do not exclude nOH. [ABSTRACT FROM AUTHOR]

Purpose: In central Lewy body diseases (LBDs) such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB), by the time parkinsonism or cognitive dysfunction becomes manifest, substantial central neurodegeneration has already occurred. Cardiovascular autonomic biomarkers might detect preclinical central LBDs in at-risk individuals, enabling possibly effective disease-modifying treatment. Methods: In the prospective, longitudinal PDRisk study, 59 participants provided information about family history of PD, olfactory dysfunction, dream enactment behavior, and orthostatic intolerance or hypotension at a protocol-specific website and were screened as outpatients. Thirty-four had three or more confirmed risk factors and were followed until PD was diagnosed or up to 7.5 years. Dependent measures included assessments of baroreflex-sympathoneural function, via the blood pressure recovery time (PRT) after release of the Valsalva maneuver and baroreflex areas; and baroreflex-cardiovagal function, via heart rate variability in the time and frequency domains and Valsalva baroslopes. Data were compared from groups with or without a subsequent diagnosis of a central LBD (LBD+, N = 9; LBD−, N = 25) and PDRisk participants with fewer than three confirmed risk factors (PDRisk−, N = 25). Results: The LBD+ group had larger orthostatic falls in systolic blood pressure than did the LBD− and PDRisk− groups (p < 0.0001 each). The LBD+ group had increased PRTs (p = 0.0114 versus LBD−, p = 0.0094 versus PDRisk−) and baroreflex areas after the Valsalva maneuver (p = 0.0225 versus LBD−, p = 0.0028 versus PDRisk−), whereas the groups did not differ in indices of baroreflex-cardiovagal function. Conclusion: Orthostatic hypotension and baroreflex-sympathoneural dysfunction characterize at-risk individuals who go on to be diagnosed with a central LBD during longitudinal follow-up. [ABSTRACT FROM AUTHOR]

Purpose: 18F-Dopamine positron emission tomography is a validated method for identifying cardiac noradrenergic deficiency, a characteristic feature of Lewy body forms of neurogenic orthostatic hypotension; however, 18F-dopamine is a research drug. Brain 18F-DOPA positron emission tomography is FDA-approved. Since 18F-DOPA is converted to 18F-dopamine in the heart, 18F-DOPA might be useful for cardiac sympathetic neuroimaging. We compared 18F-DOPA with 18F-dopamine in patients who either had or did not have low 18F-dopamine-derived radioactivity. Methods: Brain and cardiac 18F-DOPA scanning and cardiac 18F-dopamine scanning were done on separate days in patient groups with neurogenic orthostatic hypotension or Parkinsonism or control subjects across a range of values for 18F-dopamine-derived radioactivity. The lower limit of normal for myocardial 18F-dopamine-derived radioactivity was 6000 Bq-kg/cc-MBq. We also examined inter-relationships among cardiac 18F-DOPA-derived radioactivity, cardiac 18F-dopamine-derived radioactivity, putamen/occipital cortex ratios of 18F-DOPA-derived radioactivity, and Unified Parkinson Disease Rating Scale scores in patients with or without Parkinsonism. For putamen/occipital cortex ratios, the cutoff value was 2.70. Results: Twelve subjects had severely decreased and eight normal cardiac 18F-dopamine-derived radioactivity. Cardiac 18F-DOPA-derived radioactivity did not distinguish the two groups and was unrelated to 18F-dopamine-derived radioactivity. Left ventricular myocardial 18F-DOPA-derived radioactivity was poorly resolved from that in the chamber. Putamen/occipital cortex ratios of 18F-DOPA-derived radioactivity were negatively correlated with Unified Parkinson Disease Rating Scale scores (− 0.67, p = 0.0015). Conclusions: 18F-DOPA does not seem to be a valid cardiac sympathetic neuroimaging agent, although brain 18F-DOPA scanning provides a biomarker of Parkinsonism. [ABSTRACT FROM AUTHOR]

Background: Cancer patients treated with neurotoxic chemotherapy are at risk of developing neurological symptoms that can impact functional capacity and quality of life. However, there are no standardised pathways to assess and manage chemotherapy-induced peripheral neurotoxicity (CIPN). This study aimed to determine consensus on statements regarding a CIPN assessment and management clinical pathway. Methods: A CIPN clinical pathway (CIPN-path) was developed and reviewed by an expert multi-disciplinary panel and consumers. Agreement with 18 statements regarding four content themes (pretreatment review, screening and assessment, management and referral, and CIPN-path feasibility) were assessed by 70 Australian respondents (68 health professionals, 2 consumers), using a 2-stage Delphi survey process to reach consensus. Respondents rated statements using a 5-point Likert scale to determine the level of agreement, with consensus defined as ≥ 80% of respondents agreeing with each statement. Results: The consensus was reached for 14 of 18 items after stage 1 and all items after stage 2. Feedback was obtained for all items to refine the CIPN-path. There was an agreement on important characteristics of the CIPN-path, including pretreatment screening, regular patient-reported assessment, and a stepped-care approach to investigating and managing symptom burden. There was a lack of agreement on who should oversee CIPN assessment, which may differ according to the structure and resources of each site. Conclusions: There was an overall agreement concerning the CIPN-path to assess and manage CIPN, which may be adapted accordingly to the resources of each clinic. The CIPN-path may assist teams across different health services in identifying CIPN symptoms, aiding decision-making, and reducing morbidity from CIPN. [ABSTRACT FROM AUTHOR]

Anatomic co-registration of SP 123 sp I-MIBG SPECT images and low-dose chest computed tomography (CT) enabled the examination of regional SP 123 sp I-MIBG-derived radioactivity within the left-ventricular myocardium. SPECT imaging PET scanning offers several advantages over SPECT scanning. Abnormal cardiac sympathetic neuroimaging is more consistently found in PD + OH than in PD without OH, by both SP 123 sp I-MIBG SPECT scanning [[5]] and SP 18 sp F-DA PET scanning [[6]]. Keywords: MIBG; SPECT; PET; Fluorodopamine; Parkinson disease; Multiple system atrophy EN MIBG SPECT PET Fluorodopamine Parkinson disease Multiple system atrophy 95 98 4 05/05/22 20220401 NES 220401 Introduction Neuroimaging evidence indicating cardiac sympathetic denervation in the Lewy body (LB) synucleinopathy Parkinson disease (PD) and generally intact innervation in the non-LB synucleinopathy multiple system atrophy (MSA) was first reported using SP 18 sp F-dopamine ( SP 18 sp F-DA) positron emission tomography (PET) imaging [[1]]. [Extracted from the article]

The goal of this work is to build up the capability of quasi-particle simulation (QuiPS), a novel flow solver, such that it can adequately model the rarefied portion of an atmospheric reentry trajectory. Direct simulation Monte Carlo (DSMC) is the conventional solver for such conditions, but struggles to resolve transient flows, trace species, and high-level internal energy states due to stochastic noise. Quasi-particle simulation (QuiPS) is a novel Boltzmann solver that describes a system with a discretized, truncated velocity distribution function. The resulting fixed-velocity, variable weight quasi-particles enable smooth variation of macroscopic properties. The distribution function description enables the use of a variance-reduced collision model, greatly minimizing expense near equilibrium. This work presents the addition of a neutral air chemistry model to QuiPS and some demonstrative 0D simulations. The explicit representation of internal distributions in QuiPS reveals some of the flaws in existing physics models. Variance reduction, a key feature of QuiPS, can greatly reduce expense of multi-dimensional calculations, but is only cheaper when the gas composition is near chemical equilibrium. [ABSTRACT FROM AUTHOR]

Pure autonomic failure (PAF) is a rare disease in which chronic neurogenic orthostatic hypotension (nOH) dominates the clinical picture. Longitudinal studies have reported that PAF can phenoconvert to a central synucleinopathy with motor or cognitive involvement—i.e., to Parkinson disease (PD), dementia with Lewy bodies (DLB), or multiple system atrophy (MSA). These studies have classified patients clinically as having PAF based on nOH without an identified secondary cause or clinical evidence of motor or cognitive impairment due to central neurodegeneration. This approach lumps together two nOH syndromes that are pathologically and neurochemically distinct. One is characterized by intraneuronal cytoplasmic alpha-synuclein aggregates (i.e., Lewy bodies) and degeneration of postganglionic sympathetic neurons, as in PD and DLB; the other is not, as in MSA. Clinical and postmortem data show that the form of PAF that involves sympathetic intraneuronal synucleinopathy and noradrenergic deficiency can phenoconvert to PD or DLB—but not to MSA. Conversely, PAF without these features leaves open the possibility of premotor MSA. [ABSTRACT FROM AUTHOR]

Immune cell infiltration has been implicated in neurotoxic chemotherapy for cancer treatment. However, our understanding of immune processes is still incomplete and current methods of observing immune cells are time consuming or invasive. Corneal dendritic cells are potent antigen-presenting cells and can be imaged with in-vivo corneal confocal microscopy. Corneal dendritic cell densities and nerve parameters in patients treated with neurotoxic chemotherapy were investigated. Patients treated for cancer with oxaliplatin (n = 39) or paclitaxel (n = 48), 3 to 24 months prior to assessment were recruited along with 40 healthy controls. Immature (ImDC), mature (MDC) and total dendritic cell densities (TotalDC), and corneal nerve parameters were analyzed from in-vivo corneal confocal microscopy images. ImDC was increased in the oxaliplatin group (Median, Md = 22.7 cells/mm2) compared to healthy controls (Md = 10.1 cells/mm2, p = 0.001), but not in the paclitaxel group (Md = 10.6 cells/mm2). ImDC was also associated with higher oxaliplatin cumulative dose (r = 0.33, p = 0.04) and treatment cycles (r = 0.40, p = 0.01). There was no significant difference in MDC between the three groups (p > 0.05). Corneal nerve parameters were reduced in both oxaliplatin and paclitaxel groups compared to healthy controls (p < 0.05). There is evidence of elevation of corneal ImDC in oxaliplatin-treated patients. Further investigation is required to explore this potential link through longitudinal studies and animal or laboratory-based immunohistochemical research. [ABSTRACT FROM AUTHOR]

Ocular surface dysfunction is common in patients receiving anti-cancer drug treatment. The effects of paclitaxel, a neurotoxic chemotherapeutic drug, on ocular surface discomfort associated with dry eye disease was investigated. Patients with cancer who had completed paclitaxel treatment between 3 and 24 months prior to assessment (n = 29) and age- and sex-matched healthy control subjects (n = 29) were recruited and assessed with the Ocular Surface Disease Index (OSDI) to measure ocular surface discomfort. In-vivo corneal confocal microscopy was used to evaluate corneal nerve parameters in the right eye. Peripheral neurotoxicity was assessed using patient-reported outcomes and clinical grading scales. The paclitaxel group had significantly worse OSDI total scores compared with controls (Median, Md = 19.3 and Md = 0, p = 0.007, respectively). Corneal nerve fiber and inferior whorl lengths were reduced in the paclitaxel group compared with controls (14.2 ± 4.0 and 14.4 ± 4.0 mm/mm2 vs. 16.4 ± 4.0 and 16.9 ± 4.9 mm/mm2, respectively, p = 0.04). When analyzed by presence of peripheral neuropathy, paclitaxel-treated patients with neuropathy showed worse OSDI total scores compared to those without peripheral neuropathy post-treatment (p = 0.001) and healthy controls (p < 0.001). More severe ocular discomfort and worse visual function was associated with greater peripheral neurotoxicity symptoms (r = 0.60, p = 0.001) and neuropathy severity (r = 0.49, p = 0.008), respectively. Patients who have been treated with paclitaxel have a higher risk of ocular surface discomfort associated with dry eye disease, particularly those with peripheral neuropathy. Future longitudinal studies should investigate the clinical impact of corneal nerve reduction in dry eye disease. [ABSTRACT FROM AUTHOR]

The pandemic viral illness COVID-19 is especially life-threatening in the elderly and in those with any of a variety of chronic medical conditions. This essay explores the possibility that the heightened risk may involve activation of the "extended autonomic system" (EAS). Traditionally, the autonomic nervous system has been viewed as consisting of the sympathetic nervous system, the parasympathetic nervous system, and the enteric nervous system. Over the past century, however, neuroendocrine and neuroimmune systems have come to the fore, justifying expansion of the meaning of "autonomic." Additional facets include the sympathetic adrenergic system, for which adrenaline is the key effector; the hypothalamic-pituitary-adrenocortical axis; arginine vasopressin (synonymous with anti-diuretic hormone); the renin-angiotensin-aldosterone system, with angiotensin II and aldosterone the main effectors; and cholinergic anti-inflammatory and sympathetic inflammasomal pathways. A hierarchical brain network—the "central autonomic network"—regulates these systems; embedded within it are components of the Chrousos/Gold "stress system." Acute, coordinated alterations in homeostatic settings (allostasis) can be crucial for surviving stressors such as traumatic hemorrhage, asphyxiation, and sepsis, which throughout human evolution have threatened homeostasis; however, intense or long-term EAS activation may cause harm. While required for appropriate responses in emergencies, EAS activation in the setting of chronically decreased homeostatic efficiencies (dyshomeostasis) may reduce thresholds for induction of destabilizing, lethal vicious cycles. Testable hypotheses derived from these concepts are that biomarkers of EAS activation correlate with clinical and pathophysiologic data and predict outcome in COVID-19 and that treatments targeting specific abnormalities identified in individual patients may be beneficial. [ABSTRACT FROM AUTHOR]

Monoamine oxidase (MAO) plays a central role in the metabolism of the neurotransmitters dopamine, norepinephrine, and serotonin. This brief review focuses on 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is the immediate product of MAO acting on cytoplasmic dopamine. DOPAL is toxic; however, normally DOPAL is converted via aldehyde dehydrogenase (ALDH) to 3,4-dihydroxyphenylacetic acid (DOPAC), which rapidly exits the neurons. In addition to vesicular uptake of dopamine via the vesicular monoamine transporter (VMAT), the two-enzyme sequence of MAO and ALDH keeps cytoplasmic dopamine levels low. Dopamine oxidizes readily to form toxic products that could threaten neuronal homeostasis. The catecholaldehyde hypothesis posits that diseases featuring catecholaminergic neurodegeneration result from harmful interactions between DOPAL and the protein alpha-synuclein, a major component of Lewy bodies in diseases such as Parkinson disease, dementia with Lewy bodies, and pure autonomic failure. DOPAL potently oligomerizes alpha-synuclein, and alpha-synuclein oligomers impede vesicular functions, shifting the fate of cytoplasmic dopamine toward MAO-catalyzed formation of DOPAL—a vicious cycle. When MAO deaminates dopamine to form DOPAL, hydrogen peroxide is generated; and DOPAL, hydrogen peroxide, and divalent metal cations react to form hydroxyl radicals, which peroxidate lipid membranes. Lipid peroxidation products in turn inhibit ALDH, causing DOPAL to accumulate—another vicious cycle. MAO inhibition decreases DOPAL formation but concurrently increases the spontaneous oxidation of dopamine, potentially trading off one form of toxicity for another. These considerations rationalize a neuroprotection strategy based on concurrent treatment with an MAO inhibitor and an anti-oxidant. [ABSTRACT FROM AUTHOR]

Purpose: Chemotherapy-induced peripheral neuropathy (CIPN) affects up to 40% of cancer survivors and is associated with functional deficits and an increased falls incidence. There are presently no strongly recommended treatment strategies for CIPN. The aim of this study was to evaluate the impact of a multimodal exercise intervention on CIPN symptoms and related functional deficits, as well as neurophysiologic parameters.Methods: All outcomes were assessed before and after an 8-week exercise intervention (3-weekly sessions) and preceding 8-week control period at baseline, pre-exercise and post-exercise. Outcome measures were objective and patient-reported CIPN, standing and dynamic balance, mobility, quality of life, and sensory and motor nerve excitability and conduction studies.Results: Twenty-nine cancer survivors (8 male, 21 female; mean age 61.6 ± 11.8 years) with CIPN symptoms affecting function completed all assessments. Objective and patient-reported CIPN, dynamic balance, standing balance in eyes open conditions, mobility and quality of life were improved from pre- to post-exercise (4.0 < F < 10.2; p < .05), with no changes over the control period (p > .21). No changes were observed in sensory or motor neurophysiologic parameters (p > .23).Conclusions: This study provides encouraging evidence of the rehabilitative potential of multimodal exercise for persisting CIPN in a post-treatment cohort. Large randomised controlled trials are justified to confirm observed benefits and determine the mechanisms and clinical significance. [ABSTRACT FROM AUTHOR]

Synucleinopathies include Parkinson disease (PD), dementia with Lewy bodies (DLB), pure autonomic failure (PAF), and multiple system atrophy (MSA). Keywords: Supine hypertension; Atomoxetine; Ampreloxetine; Lightheadedness; Multiple system atrophy; Parkinson disease EN Supine hypertension Atomoxetine Ampreloxetine Lightheadedness Multiple system atrophy Parkinson disease 351 353 3 06/09/21 20210601 NES 210601 Neurogenic orthostatic hypotension (nOH) is a not infrequent consequence of neurodegenerative disorders and can result in impaired mobility, falls and associated fractures, decreased quality of life, hospitalizations, and increased mortality. [Extracted from the article]

This perspective piece on head-up tilt table testing is part of a series on autonomic function testing. The tilt table can be a useful diagnostic test, but methodologies vary, and the results are sometimes misinterpreted. The intent here is not to review comprehensively the utility of various tilt table testing protocols but to convey a number of general points that may give perspective and have practical clinical value, based on an understanding of autonomic physiology and our long clinical and research experience in the evaluation of autonomic disorders. The goals of tilt table testing are to assess orthostatic hypotension (OH), chronic orthostatic intolerance (COI), and unexplained syncope. The testing is useful for distinguishing neurogenic from non-neurogenic OH, identifying failure of the sympathetic noradrenergic system in autonomic neuropathies and ganglionopathies, and assessing baroreflex-sympathoneural function in α-synucleinopathies. For COI, the testing can provide objective data related to the patient's symptoms, diagnose postural tachycardia syndrome (POTS), and distinguish POTS from other causes of tachycardia. Provocative tilt table testing can help understand bases for recurrent transient loss of consciousness in patients with syncope, distinguish neurally mediated syncope from psychogenic pseudosyncope, and separate syncope-related convulsion from epileptic seizures. For each of these purposes, the goals, formats, endpoints, and clinical utility are different. As for any autonomic test, tilt table findings must be interpreted in the context of the patient's clinical presentation. [ABSTRACT FROM AUTHOR]

Sympathetic neuroimaging is based on the injection of compounds that either radiolabel sites of the cell membrane norepinephrine transporter (NET) or that are taken up into sympathetic nerves via the NET and radiolabel intra-neuronal catecholamine storage sites. Detection of the radioactivity is by planar or tomographic radionuclide imaging. The heart stands out among body organs in terms of the intensity of radiolabeling of sympathetic nerves, and virtually all of sympathetic neuroimaging focuses on the left ventricular myocardium. The most common cardiac sympathetic neuroimaging method worldwide is 123I-metaiodobenzylguanidine (123I-MIBG) scanning. 123I-MIBG scanning is used routinely in Europe and East Asia in the diagnostic evaluation of neurogenic orthostatic hypotension (nOH), to distinguish Lewy body diseases (e.g., Parkinson disease with orthostatic hypotension (OH), pure autonomic failure) from non-Lewy body diseases (e.g., multiple system atrophy) and to distinguish dementia with Lewy bodies from Alzheimer’s disease. In the USA, 123I-MIBG scanning has been approved by the Food and Drug Administration for the evaluation of pheochromocytoma and some forms of heart failure—but not for the above-mentioned differential diagnoses. Positron emission tomographic methods based on imaging agents such as 18F-dopamine are categorized as research tools, despite more than a quarter century of clinical experience with these modalities. Considering that 123I-MIBG scanning is available at most academic medical centers in the USA, cardiac sympathetic neuroimaging by this methodology merits consideration as an autonomic test, especially in patients with nOH. [ABSTRACT FROM AUTHOR]

Catechols are a class of compounds that contain adjacent hydroxyl groups on a benzene ring. Endogenous catechols in human plasma include the catecholamines norepinephrine, epinephrine (adrenaline), and dopamine; the catecholamine precursor DOPA, 3,4-dihydroxyphenylglycol (DHPG), which is the main neuronal metabolite of norepinephrine; and 3,4-dihydroxyphenylacetic acid (DOPAC), which is the main neuronal metabolite of dopamine. In the diagnostic evaluation of patients with known or suspected dysautonomias, measurement of plasma catechols is rarely diagnostic but often is informative. This review summarizes the roles of clinical catechol neurochemistry in autonomic function testing. [ABSTRACT FROM AUTHOR]

Signs of autonomic dysfunction, although at times seemingly mysterious, can contribute to diagnostic clarification and clinical investigation. Even when sophisticated autonomic testing equipment is not readily available, the experienced clinician, through educated observation and inductive reasoning—in conjunction with an intelligently obtained autonomic medical history—can discern much by a careful physical examination. Elements of the autonomic examination include variations in the pulse, postural measurements of blood pressure and heart rate, pupillary light reactions, skin coloration and temperature, patterns of sweating, and other organ-specific physical findings relevant to the individual patient’s presentation. Especially important is the often neglected practice of measuring the blood pressure standing up, for orthostatic hypotension cannot be diagnosed by symptoms alone and is a common source of potential morbidity. The examination should be carried out in the context of understanding the syndromic nature of abnormalities of components of the autonomic nervous system. [ABSTRACT FROM AUTHOR]

In this Focused Review, we provide an update about evolving concepts that may link chronic stress and catecholamine autotoxicity with neurodegenerative diseases such as Parkinson's disease. Richard Kvetnansky's contributions to the field of stress and catecholamine systems inspired some of the ideas presented here. We propose that coordination of catecholaminergic systems mediates adjustments maintaining health and that senescence-related disintegration of these systems leads to disorders of regulation and to neurodegenerative diseases such as Parkinson's disease. Chronically repeated episodes of stress-related catecholamine release and reuptake, with attendant increases in formation of the toxic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde, might accelerate this process. [ABSTRACT FROM AUTHOR]

Measurement of beat-to-beat blood pressure and heart rate responses to the Valsalva maneuver is the basis for a highly informative autonomic function test. Whereas in the past this measurement required intra-arterial cannulation, the development of finger cuff devices that acquire arterial pressure waveforms indistinguishable from those recorded intra-arterially has made it possible to obtain accurate measurements noninvasively. In a patient with orthostatic hypotension, the pattern of blood pressure responses during and after the release of the maneuver can identify a neurogenic basis: sympathetic neurocirculatory failure. The quantifiable change in cardiac interbeat interval per unit change in systolic pressure during the maneuver can identify baroreflex-cardiovagal failure. [ABSTRACT FROM AUTHOR]

The catecholaldehyde hypothesis for the pathogenesis of Parkinson's disease proposes that the deaminated dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL) is toxic to nigrostriatal dopaminergic neurons. Inhibiting monoamine oxidase (MAO) should therefore slow the disease progression; however, MAO inhibition increases spontaneous oxidation of dopamine, as indicated by increased 5-S-cysteinyl-dopamine (Cys-DA) levels, and the oxidation products may also be toxic. This study examined whether N-acetylcysteine (NAC), a precursor of the anti-oxidant glutathione, attenuates the increase in Cys-DA production during MAO inhibition. Rat pheochromocytoma PC12 cells were incubated with NAC, the MAO-B inhibitor selegiline, or both. Selegiline decreased DOPAL and increased Cys-DA levels (p < 0.0001 each). Co-incubation of NAC at pharmacologically relevant concentrations (1-10 µM) with selegiline (1 µM) attenuated or prevented the Cys-DA response to selegiline, without interfering with the selegiline-induced decrease in DOPAL production or inhibiting tyrosine hydroxylation. NAC therefore mitigates the increase in spontaneous oxidation of dopamine during MAO inhibition. [ABSTRACT FROM AUTHOR]

The most important autonomic function test-the autonomic medical history-is the patient's account, interpreted by a clinician skilled in asking the right questions, of symptoms during daily activities that relate to the autonomic nervous system. The chronology and pattern of these symptoms combine to create a portrait of autonomic function or dysfunction. We summarize the steps in obtaining a comprehensive autonomic medical history. [ABSTRACT FROM AUTHOR]

B Correction to: Clinical Autonomic Research b https://doi.org/10.1007/s10286-022-00912-y Under the discussion section, 3rd paragraph, the first sentence was incorrectly published in the original publication. Correction to: Baroreflex-sympathoneural dysfunction characterizes at-risk individuals with preclinical central Lewy body diseases The original article can be found online at https://doi.org/10.1007/s10286-022-00912-y. [Extracted from the article]

We report a case of autoimmunity-associated autonomic failure in a young adult woman who developed arthritis followed 3 years later by pandysautonomia. There was early recovery of parasympathetic functions but persistent neurogenic orthostatic hypotension from post-ganglionic sympathetic denervation. Clinical laboratory testing indicated variable amounts of sympathetic neuronal re-sprouting in the heart, kidneys, eyes, and body as a whole upon follow-up evaluation after 1.5 years. [ABSTRACT FROM AUTHOR]

The catecholaldehyde hypothesis predicts that monoamine oxidase (MAO) inhibition should slow the progression of Parkinson's disease, by decreasing production of the autotoxic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL). Inhibiting MAO, however, diverts the fate of cytoplasmic dopamine toward potentially harmful spontaneous oxidation products, indicated by increased 5-S-cysteinyl-dopamine (Cys-DA) levels. 3,4-Dihydroxyphenylethanol (hydroxytyrosol) is an abundant anti-oxidant phenol in constituents of the Mediterranean diet. Whether hydroxytyrosol alters enzymatic or spontaneous oxidation of dopamine has been unknown. Rat pheochromocytoma PC12 cells were incubated with hydroxytyrosol (10 µM, 180 min) alone or with the MAO-A inhibitor clorgyline (1 nM) or the MAO-B inhibitors rasagiline or selegiline (0.5 µM). Hydroxytyrosol decreased levels of DOPAL by 30 % and Cys-DA by 49 % ( p < 0.0001 each). Co-incubation with hydroxytyrosol prevented the increases in Cys-DA seen with all 3 MAO inhibitors. Hydroxytyrosol therefore inhibits both enzymatic and spontaneous oxidation of endogenous dopamine and mitigates the increase in spontaneous oxidation during MAO inhibition. [ABSTRACT FROM AUTHOR]

Background: Parkinson disease with orthostatic hypotension (PD + OH) and the parkinsonian form of multiple system atrophy (MSA-P) can be difficult to distinguish clinically. Recent studies indicate that PD entails a vesicular storage defect in catecholaminergic neurons. Although cardiac sympathetic neuroimaging by F-dopamine positron emission tomography can identify decreased vesicular storage, this testing is not generally available. We assessed whether plasma biomarkers of a vesicular storage defect can separate PD + OH from MSA-P. Methods: We conceptualized that after F-dopamine injection, augmented production of F-dihydroxyphenylacetic acid (F-DOPAC) indicates decreased vesicular storage, and we therefore predicted that arterial plasma F-DOPAC would be elevated in PD + OH but not in MSA-P. We measured arterial plasma F-DOPAC after F-dopamine administration (infused i.v. over 3 min) in patients with PD + OH ( N = 12) or MSA-P ( N = 21) and in healthy control subjects ( N = 26). Peak F-DOPAC:dihydroxyphenylglycol (DHPG) was also calculated to adjust for effects of denervation on F-DOPAC production. Results: Plasma F-DOPAC accumulated rapidly after initiation of F-dopamine infusion. Peak F-DOPAC (5-10 min) in PD + OH averaged three times that in MSA-P ( P < 0.0001). Among MSA-P patients, none had peak F-DOPAC > 300 nCi-kg/cc-mCi, in contrast with 7 of 12 PD + OH patients ( χ = 16.6, P < 0.0001). DHPG was lower in PD + OH (3.83 ± 0.36 nmol/L) than in MSA-P (5.20 ± 0.29 nmol/L, P = 0.007). All MSA-P patients had peak F-DOPAC:DHPG < 60, in contrast with 9 of 12 PD + OH patients ( χ = 17.5, P < 0.0001). Adjustment of peak F-DOPAC for DHPG increased test sensitivity from 58 to 81 % at similar high specificity. Interpretation: After F-dopamine injection, plasma F-DOPAC and F-DOPAC:DHPG distinguish PD + OH from MSA-P. [ABSTRACT FROM AUTHOR]

Purpose: Chronic autonomic failure syndromes such as Parkinson disease with orthostatic hypotension (PD + OH), multiple system atrophy (MSA), and pure autonomic failure (PAF) typically feature arterial baroreflex failure. Identifying baroreflex-sympathoneural failure from hemodynamic responses to the maneuver usually has been qualitative. We report quantitative methods for evaluating baroreflex-sympathoneural function, based on beat-to-beat systolic blood pressure (BPs) responses to the Valsalva maneuver. Method: Using the trapezoid rule, we calculated the area under the curve (baroreflex area, BRA) between baseline systolic blood pressure (BPs) and the BPs for each beat in Phase II (BRA-II) and Phase IV (BRA-IV) in 136 autonomic failure patients and 171 controls. The sum of the areas was defined as total BRA (BRA-T). We compared individual values by the BRA approach with those by other measures. Results: Mean values for log BRA-II, BRA-IV, and BRA-T were higher in PD + OH, PAF, and MSA than in controls ( p < 0.001 each). The log of BRA-T correlated negatively with the fractional orthostatic change in total peripheral resistance ( r = −0.41, p < 0.001), fractional orthostatic change in plasma norepinephrine ( r = −0.27, p < 0.001), orthostatic change in BPs ( r = −0.62, p < 0.001), fall in BPs in Phase II of the Valsalva ( r = 0.58, p < 0.001), and log of baroreflex-cardiovagal slope ( r = −0.40, p < 0.001). Areas under receiver operating characteristic curves were 0.85 for BRA-T and 0.89 for BRA-IV ( p < 0.001). Conclusion: The BRA approach provides quantitative measures of baroreflex-sympathoneural function. Chronic autonomic failure syndromes entail deficiencies of both the cardiovagal and sympathoneural limbs of the arterial baroreflex. [ABSTRACT FROM AUTHOR]

Energy performance indices are used around the world to evaluate and monitor residential and commercial building energy performance during design, construction, renovation, and operation. The two most common indices are Asset Ratings and Operational Ratings. Asset Ratings are based on modeled energy use with uniform conditions of climate, schedules, plug loads, occupancy, and energy management. Operational Ratings are based on measured energy use, often normalized for relevant variables like climate and level of energy service. Surprisingly, there is almost no discussion in the literature about the technical basis of these ratings and what they are attempting to measure. This paper analyzes the merits and weaknesses of the common ratings and introduces additional energy performance indices, in particular the Operation and Maintenance (O&M) Index, which is the ratio of the energy consumption as measured at the meter to the simulated energy performance, calibrated for the actual operating conditions of the building. We provide examples of how such indices are currently used, although we do so as examples to illustrate our hypothesis as to what indices are most helpful to improve energy management, rather than as a comprehensive review. We show how these indices work together to provide better feedback to energy managers. The Operational Rating answers the question: 'how does the energy intensity of this building compare to its peers?' The Asset Rating answers the question: 'how efficient is this building?' The O&M Index answers the question: 'how well is this building being managed?' These questions are useful to answer in the context of a comprehensive energy management program, such as would be required by an Energy Management System standard. [ABSTRACT FROM AUTHOR]

Purpose: Anoikis ('homelessness' in Greek) is a form of apoptosis following the detachment of cells from the appropriate extracellular matrix (Chiarugi and Giannoni in Biochem Pharmacol 76:1352-1364, ). Resistance to anoikis is a critical mediator of metastasis in cancer by enabling cancer cells to survive during invasion and transport in the blood and lymph. Numerous regulators and mechanisms of anoikis in human cancer have been proposed to date. Consequently, the identification of key regulators of anoikis that can be targeted to at least partially restore anoikis sensitivity in cancer cells is important in the development of therapies to treat metastatic cancer. Methods: A literature search focusing on the regulators of anoikis in human cancer was performed on the Medline, Embase and Scopus databases. Results: Mcl-1, Cav-1, Bcl-x, cFLIP, 14-3-3ζ and Bit1 appear to regulate anoikis in human cancer by participating in the intrinsic apoptotic pathway, extrinsic apoptotic pathway or caspase-independent pathways. Mcl-1, Cav-1, Bcl-x, cFLIP and 14-3-3ζ are suppressors of anoikis, and their upregulation confers anoikis resistance to cancer cells. Bit1 is a promoter of anoikis and is downregulated to confer anoikis resistance in metastatic cancer. Conclusion: Anoikis is a complex process involving the crosstalk between different signalling pathways. The dysregulated expression of key regulators of anoikis that participate in these signalling pathways promotes anoikis resistance in human cancer. These regulators of anoikis might therefore be the targets for developing therapies to overcome anoikis resistance in metastatic cancer. [ABSTRACT FROM AUTHOR]

Next-generation sequencing is becoming the primary discovery tool in human genetics. There have been many clear successes in identifying genes that are responsible for Mendelian diseases, and sequencing approaches are now poised to identify the mutations that cause undiagnosed childhood genetic diseases and those that predispose individuals to more common complex diseases. There are, however, growing concerns that the complexity and magnitude of complete sequence data could lead to an explosion of weakly justified claims of association between genetic variants and disease. Here, we provide an overview of the basic workflow in next-generation sequencing studies and emphasize, where possible, measures and considerations that facilitate accurate inferences from human sequencing studies. [ABSTRACT FROM AUTHOR]

A cardinal manifestation of chronic autonomic failure is neurogenic orthostatic hypotension (OH), which often is associated with supine hypertension, posing a therapeutic dilemma. We report here success in a first step toward development of a 'prosthetic baroreceptor system' to maintain blood pressure during orthostasis without worsening supine hypertension. In all of four patients with neurogenic OH, titrated i.v. NE infusion kept directly recorded intra-arterial pressure at or above baseline during progressive head-up tilt. We conclude that titrated i.v. NE infusion temporarily eliminates OH. [ABSTRACT FROM AUTHOR]

As populations age, the prevalence of geriatric neurodegenerative diseases will increase. These diseases generally are multifactorial, arising from complex interactions among genes, environment, concurrent morbidities, treatments, and time. This essay provides a concept for the pathogenesis of Lewy body diseases such as Parkinson disease, by considering them in the context of allostasis and allostatic load. Allostasis reflects active, adaptive processes that maintain apparent steady states, via multiple, interacting effectors regulated by homeostatic comparators-'homeostats.' Stress can be defined as a condition or state in which a sensed discrepancy between afferent information and a setpoint for response leads to activation of effectors, reducing the discrepancy. 'Allostatic load' refers to the consequences of sustained or repeated activation of mediators of allostasis. From the analogy of an idling car, the revolutions per minute of the engine can be maintained at any of a variety of levels (allostatic states). Just as allostatic load (cumulative wear and tear) reflects design and manufacturing variations, byproducts of combustion, and time, eventually leading to engine breakdown, allostatic load in catecholaminergic neurons might eventually lead to Lewy body diseases. Central to the argument is that catecholaminergic neurons leak vesicular contents into the cytoplasm continuously during life and that catecholamines in the neuronal cytoplasm are autotoxic. These neurons therefore depend on vesicular sequestration to limit autotoxicity of cytosolic transmitter. Parkinson disease might be a disease of the elderly because of allostatic load, which depends on genetic predispositions, environmental exposures, repeated stress-related catecholamine release, and time. [ABSTRACT FROM AUTHOR]

Braak's staging concept of Lewy body disease pathogenesis is based on a spatiotemporal sequence of alpha-synuclein deposition, with autonomic nervous system involvement before synucleinopathy in substantia nigra neurons. A patient with primary chronic autonomic failure underwent biennial brain 6-[F]DOPA and myocardial 6-[F]dopamine scanning over 4 years. Low myocardial radioactivity indicated cardiac noradrenergic denervation that persisted. Striatal 6-[F]DOPA-derived radioactivity initially was normal, 2 years later was decreased subtly, and by 4 years was clearly decreased, accompanied by dementia and parkinsonism. In this case, neuroimaging evidence of cardiac noradrenergic denervation and subsequent progressive striatal dopaminergic denervation fit with Braak staging. [ABSTRACT FROM AUTHOR]

Background: Biliary tract cancers (BTC) have a poor prognosis, and there is no consensus on the best chemotherapy regimen. This study determined the response rate for fixed-dose-rate (FDR) gemcitabine combined with cisplatin. Methods: This multicentre phase II trial enrolled 50 patients with inoperable locally advanced or metastatic BTC. Treatment consisted of FDR gemcitabine 1,000 mg/m (10 mg/m/min) and cisplatin 20 mg/m on days 1 and 8 of a 21-day cycle. The primary endpoint was response rate. Secondary endpoints included safety, response duration (RD), progression-free (PFS) and overall survival (OS), and cancer antigen 19-9 response. Results: Thirteen patients (26%, 95% CI 14.6-40.4) had a partial response, and 12 (24%) had stable disease. The median RD was 8.3 months (95% CI 6.91-9.99); median PFS 4 months (95% CI 2.5-6.77); and median OS 6.8 months (95% CI 5.0-8.7). Treatment was well tolerated. Grade 3 and grade 4 nausea, vomiting, and fatigue were uncommon. Thirty-eight per cent of patients discontinued treatment because of toxicity, patient or clinician preference. Conclusions: This treatment combination had moderate activity with acceptable toxicity, supporting previous results that this combination has a role to play. The study does not suggest that FDR gemcitabine is superior to bolus infusion. [ABSTRACT FROM AUTHOR]

This review of clinical catecholamine neurochemistry is based on the Streeten Memorial Lecture at the 19th annual meeting of the American Autonomic Society and lectures at a satellite of the 6th Congress of the International Society of Autonomic Neuroscience. Here I provide historical perspective, describe sources and meanings of plasma levels of catecholamines and their metabolites, present a model of a sympathetic noradrenergic neuron that conveys how particular aspects of sympathetic nervous function affect plasma levels of catecholamines and their metabolites, and apply the model to understand plasma neurochemical patterns associated with some drugs and disease states. [ABSTRACT FROM AUTHOR]

Based on concepts proposed by Langley, Cannon, and Selye, adrenal responses to stress occur in a syndrome that reflects activation of the sympathoadrenal system and hypothalamic-pituitary-adrenocortical (HPA) axis; and a 'stress syndrome' maintains homeostasis in emergencies such as 'fight or flight' situations, but if the stress response is excessive or prolonged then any of a variety of clinical disorders can arise. The idea of a unitary sympathoadrenal system does not account for evidence that different stressors elicit different patterns of autonomic responses, with exposure to some stressors differentially affecting sympathetic noradrenergic and adrenomedullary hormonal activities. Instead, adrenomedullary responses to stressors are more closely tied to adrenocortical than to sympathetic noradrenergic responses. Distress involves concurrent activation of the HPA and adrenomedullary neuroendocrine systems. [ABSTRACT FROM AUTHOR]

Cope's gray treefrogs, Hyla chrysoscelis, accumulate glycerol during the period of cold acclimation that leads to the development of freeze tolerance. Glycerol must cross cell membranes in numerous processes during this time, including exit from hepatocytes where glycerol is synthesized and entry into other tissues, where glycerol is cryoprotective. Thus, we hypothesized that erythrocytes from H. chrysoscelis would be permeable to glycerol and that that permeability would be up-regulated during cold acclimation. Further, we hypothesized that glycerol permeability would be associated with the expression of aquaporins, particularly those from the glyceroporin sub-family. Erythrocytes from warm-acclimated treefrogs had high glycerol permeability at 20°C, as assessed by the time required for osmotic lysis following suspension in 0.2 M glycerol. That osmotic lysis, as well as uptake of radio-labeled glycerol, was inhibited by 0.3 mM HgCl. Permeability assessed via osmotic lysis was markedly reduced at 5°C. These properties were similar in animals deriving from northern (Ohio) and southern (Alabama) populations, although suggestive (through statistical interactions) of greater glycerol permeability in northern animals. Erythrocytes expressed mRNA and protein for a previously described glyceroporin, HC-3. In cold-acclimated animals, HC-3 protein expression was up-regulated, but we could not detect a concomitant enhancement of glycerol permeability. [ABSTRACT FROM AUTHOR]

Although genome-wide association (GWA) studies for common variants have thus far succeeded in explaining only a modest fraction of the genetic components of human common diseases, recent advances in next-generation sequencing technologies could rapidly facilitate substantial progress. This outcome is expected if much of the missing genetic control is due to gene variants that are too rare to be picked up by GWA studies and have relatively large effects on risk. Here, we evaluate the evidence for an important role of rare gene variants of major effect in common diseases and outline discovery strategies for their identification. [ABSTRACT FROM AUTHOR]

Chronic autonomic failure (CAF), as in Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure (PAF), typically entails baroreflex failure, neurogenic orthostatic hypotension (NOH), and supine hypertension. The combination might predispose to cardiac ectopy, which in turn might predispose to syncope and falls during manipulations decreasing venous return to the heart. This study assessed whether CAF is associated with an increased prevalence of cardiac ectopy. Recordings lasting ≥15 min of the electrocardiogram, beat-to-beat heart rate, and continuous blood pressure were reviewed from a total of 97 CAF patients (34 PD + NOH, 48 MSA, 15 PAF) and 82 control subjects (41 PD without NOH, 33 non-parkinsonian patients, 8 healthy volunteers). Cardiac ectopy was considered present if there were at least two premature beats or an arrhythmia. Atrial ectopy was found in 74% of patients with PD + NOH, 68% with MSA, and 63% with PAF, prevalences 2–3 times those in PD without NOH (28%, p < 0.0001) or other controls (24%, p < 0.0001). Atrial ectopy was related to subject age ( p < 0.0001), supine systolic pressure ( p < 0.0001), and the orthostatic fall in systolic pressure ( p = 0.0007) and inversely with baroreflex-cardiovagal gain ( p = 0.005) and the orthostatic increment in plasma norepinephrine ( p = 0.0004). In two PD + NOH patients, atrial ectopy was associated with documented sustained hypotension after the Valsalva maneuver; and in an MSA patient, acute atrial flutter/fibrillation was associated with sudden loss of consciousness. CAF patients have a relatively high frequency of atrial ectopy, which might interact with baroreflex failure to increase morbidity from orthostatic hypotension. [ABSTRACT FROM AUTHOR]

The First International Symposium on Cardiac Sympathetic Neuroimaging brought together for the first time clinical and preclinical researchers evaluating autonomic and neurocardiologic disorders by this modality. The invited lectures and posters presented some uses of cardiac sympathetic neuroimaging for diagnosis, prognosis, and monitoring treatments. The Symposium also included a discussion about whether and how to expand the availability of cardiac sympathetic neuroimaging at medical centers in the United States. Here, we review the background for the Symposium, provide an annotated summary of the lectures and posters, discuss some of the take-home points from the roundtable discussion, and propose a plan of action for the future. [ABSTRACT FROM AUTHOR]

Familial dysautonomia (FD) involves incomplete development of the sympathetic nervous system. Whether such loss extends to sympathetic innervation of the heart has been unknown. This study used 6-[18F]fluorodopamine neuroimaging to assess cardiac sympathetic innervation and function in FD. Six adult FD patients underwent thoracic PET scanning for 30 minutes after i.v. 6-[18F]fluorodopamine injection, as did healthy volunteers without ( N = 21) or with ( N = 10) pre-treatment by desipramine, which interferes with neuronal uptake and thereby simulates effects of noradrenergic denervation. Effective rate constants for uptake and loss were calculated using a single compartment pharmacokinetic model. FD patients had decreased uptake and accelerated loss of 6-[18F]fluorodopamine-derived radioactivity in the interventricular myocardial septum ( P = 0.009, P = 0.05) and ventricular free wall ( P = 0.007, P < 0.001), compared to untreated controls. Desipramine-treated subjects had decreased uptake but normal loss of 6-[18F]fluorodopamine-derived radioactivity. FD involves cardiac noradrenergic hypo-innervation. Since accelerated loss of 6-[18F]fluorodopamine-derived radioactivity cannot be explained by decreased neuronal uptake alone, FD may also involve augmented NE loss from extant terminals. [ABSTRACT FROM AUTHOR]

To fully exploit the potential of kinases as drug targets, novel strategies for the efficient discovery of inhibitors are required. In contrast to the traditional, linear process of inhibitor discovery, high-throughput kinase profiling enables a parallel approach by interrogating compounds against hundreds of targets in a single screen. Compound potency and selectivity are determined simultaneously, providing a choice of targets to pursue that is guided by the quality of lead compounds available, rather than by target biology alone. [ABSTRACT FROM AUTHOR]

Pure autonomic failure (PAF) and Parkinson’s disease (PD) share several clinical laboratory abnormalities; however, PAF is not associated with parkinsonism. In this study, we tested the hypothesis that preservation of nigrostriatal dopaminergic innervation explains the absence of motor dysfunction in PAF. Patients with PAF ( N = 5) or PD ( N = 21) and control subjects ( N = 14) had brain 6-[18F]fluorodopa positron emission tomographic scanning and cerebrospinal fluid catechol measurements. A patient with PAF and another with PD had rapid postmortem striatal, nigral, and sympathetic ganglion sampling, with assays of catechols and tyrosine hydroxylase activity. The PAF and PD groups had similarly low mean substantia nigra (SN):occipital (OCC) ratios of 6-[18F]fluorodopa-derived radioactivity and similarly low cerebrospinal fluid dihydroxyphenylacetic acid and DOPA levels. Only the PD group, however, had low PUT:OCC, caudate:OCC, or PUT:SN ratios. The PAF and PD cases had similarly low SN tissue concentrations of dopamine and tyrosine hydroxylase activity, but the PD patient had tenfold lower PUT dopamine and the PAF patient 15-fold lower myocardial norepinephrine concentrations. Surprisingly, PAF and PD entail similarly severe nigral and overall central dopaminergic denervation. There is more severe loss of striatal dopaminergic terminals in PD than in PAF and more severe loss of sympathetic noradrenergic terminals in PAF than in PD. These differences explain the distinctive clinical manifestations of the two Lewy body diseases. Parkinsonism appears to reflect striatal dopamine deficiency rather than loss of nigral dopaminergic neurons per se. [ABSTRACT FROM AUTHOR]

Maintenance of fluid homeostasis is critical to establishing and maintaining normal physiology. The landmark discovery of membrane water channels (aquaporins; AQPs) ushered in a new area in osmoregulatory biology that has drawn from and contributed to diverse branches of biology, from molecular biology and genomics to systems biology and evolution, and from microbial and plant biology to animal and translational physiology. As a result, the study of AQPs provides a unique and integrated backdrop for exploring the relationships between genes and genome systems, the regulation of gene expression, and the physiologic consequences of genetic variation. The wide species distribution of AQP family members and the evolutionary conservation of the family indicate that the control of membrane water flux is a critical biological process. AQP function and regulation is proving to be central to many of the pathways involved in individual physiologic systems in both mammals and anurans. In mammals, AQPs are essential to normal secretory and absorptive functions of the eye, lung, salivary gland, sweat glands, gastrointestinal tract, and kidney. In urinary, respiratory, and gastrointestinal systems, AQPs are required for proper urine concentration, fluid reabsorption, and glandular secretions. In anurans, AQPs are important in mediating physiologic responses to changes in the external environment, including those that occur during metamorphosis and adaptation from an aquatic to terrestrial environment and thermal acclimation in anticipation of freezing. Therefore, an understanding of AQP function and regulation is an important aspect of an integrated approach to basic biological research. [ABSTRACT FROM AUTHOR]

There is substantial interest in identifying biomarkers to detect early Parkinson disease (PD). Cardiac noradrenergic denervation and attenuated baroreflex-cardiovagal function occur in de novo PD, but whether these abnormalities can precede PD has been unknown. Here we report the case of a patient who had profoundly decreased left ventricular myocardial 6-[18F]fluorodopamine-derived radioactivity and low baroreflex-cardiovagal gain, 4 years before the onset of symptoms and signs of PD. The results lead us to hypothesize that cardiac noradrenergic denervation and decreased baroreflex-cardiovagal function may occur early in the pathogenesis of PD. [ABSTRACT FROM AUTHOR]

In this study we evaluated by indirect immunohistochemistry the prevalence of cerebrospinal fluid (CSF) antibodies reacting with structures of rat pons/medulla in patients with multiple system atrophy (MSA) ( n = 29), Parkinson disease with neurogenic orthostatic hypotension ( n = 13), or pure autonomic failure ( n = 11) and in control subjects without autonomic failure ( n = 33). About 10–20% of CSF samples had positive immunoreactivity to rat locus coeruleus (LC), regardless of clinical diagnosis. The results failed to confirm the previously reported high prevalence of immune binding to rat LC in CSF from patients with MSA. [ABSTRACT FROM AUTHOR]

Genomics is now a core element in the effort to develop a vaccine against HIV-1. Thanks to unprecedented progress in high-throughput genotyping and sequencing, in knowledge about genetic variation in humans, and in evolutionary genomics, it is finally possible to systematically search the genome for common genetic variants that influence the human response to HIV-1. The identification of such variants would help to determine which aspects of the response to the virus are the most promising targets for intervention. However, a key obstacle to progress remains the scarcity of appropriate human cohorts available for genomic research. [ABSTRACT FROM AUTHOR]

Patients with Parkinson’s disease (PD) commonly have clinically significant orthostatic hypotension (OH). In such patients PD+OH might be confused with multiple system atrophy (MSA), in which OH is a frequent finding, or with pure autonomic failure (PAF), if OH preceded clinical manifestations of the movement disorder. This study addressed whether OH can occur as an early finding in PD+OH.Historical data were analyzed from 35 patients with PD+OH evaluated at the NIH. OH was considered early if the patient had OH before, concurrent with, or starting within 1 year after onset of a symptomatic movement disorder. MSA was excluded by myocardial 6-[18F]fluorodopamine-derived radioactivity more than 2 standard deviations below the normal mean. Among the 35 PD+OH patients, 21 (60 %) had documentation of OH as an early finding. In 4 such patients, OH had preceded parkinsonism, and in 4 others, OH had dominated the early clinical picture, even after cessation of levodopa treatment for the movement disorder. In PD, OH can occur early in the disease, occasionally preceding or overshadowing the movement disorder. [ABSTRACT FROM AUTHOR]