ARTICLE | doi:10.20944/preprints201807.0415.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: HPA axis, Bipolar II disorder, perturbation, cortisol
Online: 23 July 2018 (11:28:30 CEST)
Using analytic approach we study the effect of HPA axis secretions to the emotional variation of bipolar II disorder patient. Modified Duffing – Van der Pol oscillator was used to model the emotional variation, that was solved analytically using multiple scale perturbation to obtain an asymptotic solution. The solution was graphed to understand the effect of the variation of the cortisol to the oscillator. It was observed that the increase or decrease of the HPA hormone from the basal level in the body system, affects the mood variation of bipolar II disorder patients.
ARTICLE | doi:10.20944/preprints201710.0047.v2
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: HPA axis; NGFs; psychiatric disorders; prevention of mental diseases; stress
Online: 4 December 2017 (07:45:28 CET)
Apart from their established role in embryonic development Nerve Growth Factors (NGFs) have diverse functions in the nervous system. Their role in integration of physiological functioning of the nervous system is now attracting attention. In the present analysis, we propose a novel paradigm about a novel role of NGFs: NGFs play imperative role in maintaining psychological integrity of an individual as a biological system. This function may be mediated through HPA-axis- operated homeostatic mechanisms; stress induced disruption of which may lead to psychiatric disorders. Current literature suggests existence of constitutive homeostatic regulatory mechanisms for NGFs disruption which may lead to pertinent and imperative behavioural effects. NGFs are known to play crucial role in endocrine regulation. This is especially true with the prototype ‘NGF’ and Brain Derived Neurotrophic Factor (BDNF). These moieties have been observed to play important function in maintaining neuro-endocrine homeostasis thereby having a profound impact on the psychological health of an individual. Role of NGFs and HPA-axis activation (in separate studies) in developing psychiatric disorders - especially those born of stress - have been reported. Literature suggests their unique interplay for producing a common effect which might be implicated in stress induced genesis of psychiatric disorders. This aspect, therefore, needs to be elucidated further as a disease etiogenesis model. This model may yield important insights into the biology of psychiatric disorders and may open ways for new therapeutic approaches.
TECHNICAL NOTE | doi:10.20944/preprints201912.0256.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: PAPR; HPA; OPS-SAP; PER; fading models
Online: 19 December 2019 (09:13:40 CET)
Peak-to-Average Power Ratio (PAPR) is one of the main problems in wireless communications using Orthogonal Frequency Division Multiplexing (OFDM). Its behavior is random and can produce problems for the hardware implementation, directly influencing the Packet Error Rate (PER). In this article, the PER is obtained for channels with Rayleigh and Rician fading. In the simulation, a High Power Amplifier (HPA) is added to the transmitter and for PAPR reduction Simple Amplitude Predistortion-Orthogonal Pilot Sequences (OPS-SAP) technique is used.
BRIEF REPORT | doi:10.20944/preprints202108.0407.v1
Subject: Biology, Animal Sciences & Zoology Keywords: Hair; HPA-axis; Koalas; Rehabilitation Sanctuary; Stress; Faeces; Glucocorticoids
Online: 20 August 2021 (08:52:07 CEST)
Koalas (Phascolarctos cinereus) are one of Australia's most charismatic native small marsupial species. Unfortunately, populations of koalas are rapidly declining throughout Australia and they continue to face increasing pressure from a changing ecosystem. Negative stimulants in the environment can elicit stress responses through activation of the hypothalamic-pituitary-adrenal (HPA) axis. Depending on the duration of the negative stimulant, the stress response can lead to either acute or chronic side effects, and is shown through the activation of the neuroendocrine stress system and the release of glucocorticoids (e.g., cortisol). Wild koalas entering clinical care face novel stressors that can be out of a wildlife carer's control. In this pilot study, we monitored physiological stress in three wild koalas at a wildlife rehabilitation centre in New South Wales, Australia. Acute and chronic stress was indexed non-invasively, with faecal samples taken to evaluate acute stress, and fur samples taken to evaluate chronic stress. Sampling occurred sporadically over four months, from the start of September 2018 to the end of December 2018. Results attempt to understand the stress response of koalas to negative stimulants in the environment by comparing faecal glucocorticoids on days where a known stressor was recorded with days where no known stressor was recorded. Furthermore, variations in faecal and fur glucocorticoids were compared between the three koalas in this study. To our knowledge, this is the first evidence of stress tracking of wild rescued koalas in a sanctuary. We suggest that further monitoring of baseline, acute and chronic stress will be needed to better understand how koalas respond to negative stimulants associated with clinical care.
Subject: Behavioral Sciences, Behavioral Neuroscience Keywords: biological clocks; circadian rhythm disorders; mental disorders; melatonin; HPA-axis
Online: 16 May 2020 (17:18:55 CEST)
Objective: Several lines of evidence support a relationship between circadian rhythms disruption in the onset, course, and maintenance of mental disorders. Despite the study of circadian phenotypes promising a decent understanding of the pathophysiologic or etiologic mechanisms of psychiatric entities, several questions still need to be addressed. In this review, we aimed to synthesize the literature investigating chronobiologic theories and their associations with psychiatric entities. Methods: The Medline, Embase, PsycInfo, and Scopus databases were comprehensively and systematically searched and articles published between January 1990 and October 2019 were reviewed. Different combinations of the relevant keywords were polled. We first introduced molecular elements and mechanisms of the circadian system to promote a better understanding of the chronobiologic implications of mental disorders. Then, we comprehensively and systematically reviewed circadian system studies in mood disorders, schizophrenia, and anxiety disorders. Results: Although subject characteristics and study designs vary across studies, current research has demonstrated that circadian pathologies, including genetic and neurohumoral alterations, represent the neural substrates of the pathophysiology of many psychiatric disorders. Impaired HPA-axis function-related glucocorticoid rhythm and disrupted melatonin homeostasis have been prominently demonstrated in schizophrenia and other psychotic disorders, while alterations of molecular expressions of circadian rhythm genes including CLOCK, PER, and CRY have been reported to be involved in the pathogenesis of mood disorders. Discussion: Further translational work is needed to identify the causal relationship between circadian physiology abnormalities and mental disorders and related psychopathology, and to develop sound pharmacologic interventions.
REVIEW | doi:10.20944/preprints202201.0222.v1
Subject: Behavioral Sciences, Behavioral Neuroscience Keywords: Tics; Emotions; Basal ganglia; Tourette's syndrome; dopamine; HPA-axis; Premontory sensory phenomena
Online: 17 January 2022 (12:28:48 CET)
Tics can be associated with neurological disorders and are thought to be the result of dysfunctional basal ganglia pathways. In Tourette Syndrome (TS), excess dopamine in the striatum is thought to excite the thalamo-cortical circuits, producing tics. When external stressors activate the hypothalamic-pituitary-adrenal (HPA) axis, more dopamine is produced, furthering the excitation of tic-producing pathways. Emotional processing structures in the limbic are also activated during tics, providing further evidence of a possible emotional component in motor ticking behaviors. The purpose of the review is to better understand the relationship between emotional states and ticking behavior. We found support for the notion that premonitory-sensory phenomena (PSP), sensory stimulation, and other environmental stressors that impact the HPA-axis can influence tics through dopaminergic neurotransmission. Dopamine plays a vital role in cognition and motor control, and is an important neurotransmitter in the pathophysiology of other disorders such as obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD), which tend to be comorbid with ticking disorders and are thought to use similar pathways. It is concluded that there is an emotional component to ticking behaviors. Emotions primarily involving anxiety, tension, stress, and frustration have been associated with exacerbated tics, with PSP contributing to these feelings.
REVIEW | doi:10.20944/preprints202208.0278.v1
Subject: Medicine & Pharmacology, Other Keywords: central stress response system; sympathetic activity; HPA axis; SAR-CoV-2; catecholamine; corti-costeriods; clonidine; dexamethasone
Online: 16 August 2022 (05:07:18 CEST)
We are in amidst of COVID-19 pandemic. Since Dec 2019, severe acute respiratory corona virus (SAR-CoV-2) has infected more than half a billion people killing nearly 7 million people worldwide. Now the BA.5 variant of SARS-CoV-2 is causing mayhem and driving the global surge. Epidemiologist are aware of the fact that this virus is capable of escaping immunity and likely to infect the same person multiple times despite adequate vaccination status. Elderly people of age more than 60 years and those with underlying health conditions are considered as high-risk who are likely to suffer complications and death. While it is tempting to frame complications and mortality from COVID-19 as a simple matter of too much of a virulent virus in too weak of a host, much more is at play here. Framing the pathophysiology of COVID-19 in the context of the Chrousos and Gold model of the central stress response system can shed insight into its complex pathogenesis. Understanding the mechanisms by which pharmacologic modulation of the central stress response system via administration of clonidine and/or dexamethasone may offer an explanation as to why a viral pathogen can be well tolerated and cleared by one host while inflaming and killing another.
REVIEW | doi:10.20944/preprints202007.0061.v1
Subject: Life Sciences, Biochemistry Keywords: COVID-19; SARS-CoV-2; Coronavirus; Substance Use Disorder (SUD); Immunology; Neuroinflammation; Blood-Brain Barrier (BBB); hypothalamic–pituitary–adrenal (HPA) axis
Online: 5 July 2020 (10:21:47 CEST)
As the world endures the coronavirus disease 2019 (COVID-19) pandemic, conditions of 35 million vulnerable individuals struggling with substance use disorders (SUDs) worldwide have not received sufficient attention for their special health and medical needs. Many of these individuals are complicated by underlying health conditions, such as cardiovascular and lung diseases and undermined immune systems. During the pandemic, access to the healthcare systems and support groups is greatly diminished. Current research on COVID-19 has not addressed the unique challenges facing individuals with SUDs, including the heightened vulnerability and susceptibility to the disease. In this systematic review, we will discuss the pathogenesis and pathology of COVID-19, and highlight potential risk factors and complications to these individuals. We will also provide insights and considerations for COVID-19 treatment and prevention in patients with SUDs.