Medical Physiology Commons^™

Prolonged Qt Interval In Hiv-1 Infected Humanized Mice Treated Chronically With Dolutegravir/Tenofovir Disoproxil Fumarate/Emtricitabine, Ali Namvaran, Julian V. Garcia, Mahendran Ramasamy, Kayla Nguyen, Farzaneh Tavakkoli Ghazani, Bryan T. Hackfort, Prasanta Dash, Reagan E. Fisher, Benson J. Edagwa, Santhi Gorantla, Keshoer R. Bidasee

Journal Articles: Cellular & Integrative Physiology

The REPRIEVE Trial recently reported high rates of sudden cardiac death (SCD) middle-aged people living with HIV-1 infection (PWH) using the WHO/NIH-recommended two nucleoside reverse transcriptase inhibitors (NRTIs)/one integrase strand inhibitor (INSTI) regimen to manage HIV-1 viremia. To date, clinically relevant animal models to delineate underlying causes for this remain limited. Here, we assessed if HIV-1-infected NOD.Cg-Prkdc^scidIl2rg^tm1Wjl/SzJ humanized mice (Hu-mice) treated with the WHO/NIH-recommended antiretroviral regimen, dolutegravir (DTG, INSTI)/tenofovir disoproxil fumarate (TDF, NRTIs)/emtricitabine (FTC, NRTIs), can recapitulate abnormalities in the ECG and subclinical structural heart disease that serve as harbingers of SCD in middle-aged PWH. …

Ambulatory Arterial Stiffness Index: Regression Method Comparison And Its Association With Pulse Pressure And Circadian Patterns, José R. Ayala-Hernández, Cristina López-Sánchez, Orlando M. Ayala, Camilo E. Palencia-Tejedor

Engineering Technology Faculty Publications

The Arterial Stiffness Index (AASI) is a calculation obtained through Ambulatory Blood Pressure Monitoring (ABPM), and is an indirect measure of the elastic properties of the arterial wall; but there is heterogeneity in its scope as a predictor of vascular wall health. A comparison is made between linear regression and exponential regression of the AASI, as well as an analysis of variance, according to circadian patterns and pulse pressure (PP) values. This work is an analytical observational study in 106 individuals, most of them women (63%) with a mean age of 53 ± 17.32 years. The coefficient of determination (r2) …

Eeg Spectral Analysis Of Nighttime Sleep And Daytime Mslts And Neurocognitive Evaluations In Subjects With Co-Morbid Insomnia And Osa, Yuan Shi, Yuru Nie, Fengyi Hao, Xujun Feng, Ye Zhang, Larry D. Sanford, Rong Ren, Xiangdong Tang

Department of Biomedical and Translational Sciences Faculty Publications

Background

Chronic insomnia and obstructive sleep apnea commonly co-occur. Few studies have explored the neurophysiological and neurocognitive characteristics of COMISA, which could help guide improving treatment diagnostic tools and determining novel therapeutic targets. This study aims to explore the neurophysiological and neurocognitive characteristics of COMISA using electroencephalographic (EEG) spectral analysis and subjective and objective neurocognitive measurements.

Methods

Participants were from our community recruited OSA-insomnia-COMISA cohort with 206 included for our current analysis including 74 chronic insomniacs (CIs), 55 OSA patients and 77 COMISA patients. Standard polysomnography (PSG) and multiple sleep latency tests (MSLTs) were recorded and used to obtain relative …

Cardiac Timing Effects On Response Speed Are Modulated By Blood Pressure But Not Heart Rate Variability In Healthy Young Adults, Xiao Yang, Catalina Roldan, Michael Gazzanigo, Yasmine Nabulsi, Fang Fang

Research and Infrastructure Service Enterprise (RISE) Faculty Publications

Cardiac timing effects reflect the dynamic interplay between interoceptive and exteroceptive processes. Human information processing tends to be facilitated during cardiac diastole and inhibited during systole, reflecting autonomic regulation and the neuromodulation by baroreceptor afferents. Thus, blood pressure (BP) and vagally-mediated heart rate variability (vmHRV) are potential modulators of those effects. Additionally, cognitive control appears to play a critical role in the processes. However, whether cardiac timing effects are influenced by those factors remains unclear. The present study aimed to clarify these relationships. Fifty-one healthy young adults completed three experimental sessions to assess BP, short-term HRV, and cardiac timing effects. …

Vascular Risk Reduction In Obesity Through Reduced Granulocyte Burden And Improved Angiogenic Monocyte Content Following Bariatric Surgery., David A Hess, Justin Z Trac, Stephen A Glazer, Daniella C Terenzi, Adrian Quan, Hwee Teoh, Mohammed Al-Omran, Deepak L Bhatt, C David Mazer, Ori D Rotstein, Subodh Verma

Physiology and Pharmacology Publications

Bariatric surgery, in addition to the benefit of sustained weight loss, can also reduce cardiometabolic risk and mortality. Lifelong vessel maintenance is integral to the prevention of cardiovascular disease. Using aldehyde dehydrogenase activity, an intracellular detoxifying enzyme present at high levels within pro-vascular progenitor cells, we observed an association between chronic obesity and "regenerative cell exhaustion" (RCE), a pathology whereby chronic assault on circulating regenerative cell types can result in adverse inflammation and diminished vessel repair. We also describe that, at 3 months following bariatric surgery, systemic inflammatory burden was reduced and pro-angiogenic macrophage precursor content was improved in subjects …

Distinct White Matter Changes Associated With Cerebrospinal Fluid Amyloid-Β1-42 And Hypertension, Omar M. Al-Janabi, Christopher A. Brown, Ahmed A. Bahrani, Erin L. Abner, Justin M. Barber, Brian T. Gold, Larry B. Goldstein, Richard R. Murphy, Peter T. Nelson, Nathan F. Johnson, Leslie M. Shaw, Charles D. Smith, John Q. Trojanowski, Donna M. Wilcock, Gregory A. Jicha

Sanders-Brown Center on Aging Faculty Publications

BACKGROUND: Alzheimer's disease (AD) pathology and hypertension (HTN) are risk factors for development of white matter (WM) alterations and might be independently associated with these alterations in older adults.

OBJECTIVE: To evaluate the independent and synergistic effects of HTN and AD pathology on WM alterations.

METHODS: Clinical measures of cerebrovascular disease risk were collected from 62 participants in University of Kentucky Alzheimer's Disease Center studies who also had cerebrospinal fluid (CSF) sampling and MRI brain scans. CSF Aβ_1-42 levels were measured as a marker of AD, and fluid-attenuated inversion recovery imaging and diffusion tensor imaging were obtained to assess …

Disruption Of Hippocampal Multisynaptic Networks By General Anesthetics., Min-Ching Kuo, L Stan Leung

Physiology and Pharmacology Publications

BACKGROUND: Previous studies showed that synaptic transmission is affected by general anesthetics, but an anesthetic dose response in freely moving animals has not been done. The hippocampus provides a neural network for the evaluation of isoflurane and pentobarbital on multisynaptic transmission that is relevant to memory function.

METHODS: Male Long-Evans rats were implanted with multichannel and single electrodes in the hippocampus. Spontaneous local field potentials and evoked field potentials were recorded in freely behaving rats before (baseline) and after various doses of isoflurane (0.25 to 1.5%) and sodium pentobarbital (10 mg/kg intraperitoneal).

RESULTS: Monosynaptic population excitatory postsynaptic potentials at the …

Metabolic And Molecular Insights Into An Essential Role Of Nicotinamide Phosphoribosyltransferase., Li Q. Zhang, Leon Van Haandel, Min Xiong, Peixin Huang, Daniel P. Heruth, Chengpeng Bi, R Gaedigk, Xun Jiang, Ding-You Li, Gerald Wyckoff, Dmitry N. Grigoryev, Li Gao, Linheng Li, Min Wu, J Steven Leeder, Shui Qing Ye

Manuscripts, Articles, Book Chapters and Other Papers

Nicotinamide phosphoribosyltransferase (NAMPT) is a pleiotropic protein implicated in the pathogenesis of acute respiratory distress syndrome, aging, cancer, coronary heart diseases, diabetes, nonalcoholic fatty liver disease, obesity, rheumatoid arthritis, and sepsis. However, the underlying molecular mechanisms of NAMPT in these physiological and pathological processes are not fully understood. Here, we provide experimental evidence that a Nampt gene homozygous knockout (Nampt-/-) resulted in lethality at an early stage of mouse embryonic development and death within 5-10 days in adult mice accompanied by a 25.24±2.22% body weight loss, after the tamoxifen induction of NamptF/F × Cre mice. These results substantiate that Nampt …

Associative Spike Timing-Dependent Potentiation Of The Basal Dendritic Excitatory Synapses In The Hippocampus In Vivo., Thomas K Fung, Clayton S Law, L Stan Leung

Physiology and Pharmacology Publications

Spike timing-dependent plasticity in the hippocampus has rarely been studied in vivo. Using extracellular potential and current source density analysis in urethane-anesthetized adult rats, we studied synaptic plasticity at the basal dendritic excitatory synapse in CA1 after excitation-spike (ES) pairing; E was a weak basal dendritic excitation evoked by stratum oriens stimulation, and S was a population spike evoked by stratum radiatum apical dendritic excitation. We hypothesize that positive ES pairing-generating synaptic excitation before a spike-results in long-term potentiation (LTP) while negative ES pairing results in long-term depression (LTD). Pairing (50 pairs at 5 Hz) at ES intervals of -10 …

Faster Movement Speed Results In Greater Tendon Strain During The Loaded Squat Exercise, Jacob E. Earp, Robert U. Newton, Prue Cormie, Anthony J. Blazevich

Research outputs 2014 to 2021

Introduction:

Tendon dynamics influence movement performance and provide the stimulus for long-term tendon adaptation. As tendon strain increases with load magnitude and decreases with loading rate, changes in movement speed during exercise should influence tendon strain.

Methods:

Ten resistance-trained men [squat one repetition maximum (1RM) to body mass ratio: 1.65 ± 0.12] performed parallel-depth back squat lifts with 60% of 1RM load at three different speeds: slow fixed-tempo (TS: 2-s eccentric, 1-s pause, 2-s concentric), volitional-speed without a pause (VS) and maximum-speed jump (JS). In each condition joint kinetics, quadriceps tendon length (L_T), patellar tendon force (F_{T …}

Over-Expression Of Copper/Zinc Superoxide Dismutase In The Median Preoptic Nucleus Attenuates Chronic Angiotensin Ii-Induced Hypertension In The Rat., John P. Collister, Mitch Bellrichard, Donna Drebes, David Nahey, Jun Tian, Matthew C. Zimmerman

Journal Articles: Cellular & Integrative Physiology

The brain senses circulating levels of angiotensin II (AngII) via circumventricular organs, such as the subfornical organ (SFO), and is thought to adjust sympathetic nervous system output accordingly via this neuro-hormonal communication. However, the cellular signaling mechanisms involved in these communications remain to be fully understood. Previous lesion studies of either the SFO, or the downstream median preoptic nucleus (MnPO) have shown a diminution of the hypertensive effects of chronic AngII, without providing a clear explanation as to the intracellular signaling pathway(s) involved. Additional studies have reported that over-expressing copper/zinc superoxide dismutase (CuZnSOD), an intracellular superoxide (O2·-) scavenging enzyme, in …

Medial Septal Cholinergic Neurons Modulate Isoflurane Anesthesia., Siew Kian Tai, Jingyi Ma, L Stan Leung

Physiology and Pharmacology Publications

BACKGROUND: Cholinergic drugs are known to modulate the response of general anesthesia. However, the sensitivity of isoflurane or other volatile anesthetics after selective lesion of septal cholinergic neurons that project to the hippocampus is not known.

METHODS: Male Long Evans rats had 192 immunoglobulin G-saporin infused into the medial septum (n = 10), in order to selectively lesion cholinergic neurons, whereas control, sham-lesioned rats were infused with saline (n = 12). Two weeks after septal infusion, the hypnotic properties of isoflurane and ketamine were measured using a behavioral endpoint of loss of righting reflex (LORR). Septal lesion was assessed by …

Septohippocampal Gabaergic Neurons Mediate The Altered Behaviors Induced By N-Methyl-D-Aspartate Receptor Antagonists., Jingyi Ma, Siew Kian Tai, L Stan Leung

Physiology and Pharmacology Publications

We hypothesize that selective lesion of the septohippocampal GABAergic neurons suppresses the altered behaviors induced by an N-methyl-D-aspartate (NMDA) receptor antagonist, ketamine or MK-801. In addition, we hypothesize that septohippocampal GABAergic neurons generate an atropine-resistant theta rhythm that coexists with an atropine-sensitive theta rhythm in the hippocampus. Infusion of orexin-saporin (ore-SAP) into the medial septal area decreased parvalbumin-immunoreactive (GABAergic) neurons by ~80%, without significantly affecting choline-acetyltransferase-immunoreactive (cholinergic) neurons. The theta rhythm during walking, or the immobility-associated theta induced by pilocarpine, was not different between ore-SAP and sham-lesion rats. Walking theta was, however, more disrupted by atropine sulfate in ore-SAP than …

Essential Role Of Caveolin-3 In Adiponectin Signalsome Formation And Adiponectin Cardioprotection., Yajing Wang, Xiaoliang Wang, Jean-François Jasmin, Wayne Bond Lau, Rong Li, Yuexin Yuan, Wei Yi, Kurt Chuprun, Michael P. Lisanti, Walter J Koch, Erhe Gao, Xin-Liang Ma

Department of Emergency Medicine Faculty Papers

OBJECTIVE: Adiponectin (APN) system malfunction is causatively related to increased cardiovascular morbidity/mortality in diabetic patients. The aim of the current study was to investigate molecular mechanisms responsible for APN transmembrane signaling and cardioprotection.

METHODS AND RESULTS: Compared with wild-type mice, caveolin-3 knockout (Cav-3KO) mice exhibited modestly increased myocardial ischemia/reperfusion injury (increased infarct size, apoptosis, and poorer cardiac function recovery; P

CONCLUSIONS: Taken together, these results demonstrated for the first time that Cav-3 plays an essential role in APN transmembrane signaling and APN anti-ischemic/cardioprotective actions.

Aberrant Promoter Cpg Methylation Is A Mechanism For Impaired Phd3 Expression In A Diverse Set Of Malignant Cells., Trenton L. Place, Matthew P. Fitzgerald, Sujatha Venkataraman, Sabine U. Vorrink, Adam J. Case, Melissa L.T. Teoh, Frederick E. Domann

Journal Articles: Cellular & Integrative Physiology

BACKGROUND: The prolyl-hydroxylase domain family of enzymes (PHD1-3) plays an important role in the cellular response to hypoxia by negatively regulating HIF-α proteins. Disruption of this process can lead to up-regulation of factors that promote tumorigenesis. We observed decreased basal expression of PHD3 in prostate cancer tissue and tumor cell lines representing diverse tissues of origin. Furthermore, some cancer lines displayed a failure of PHD3 mRNA induction when introduced to a hypoxic environment. This study explores the mechanism by which malignancies neither basally express PHD3 nor induce PHD3 under hypoxic conditions.

METHODOLOGY/PRINCIPAL FINDINGS: Using bisulfite sequencing and methylated DNA enrichment …

A Drosophila Deg/Enac Channel Subunit Is Required For Male Response To Female Pheromones, Heping Lin, Kevin J. Mann, Elena Starostina, Ronald D. Kinser, Claudio W. Pikielny

Dartmouth Scholarship

Odorants and pheromones as well as sweet- and bitter-tasting small molecules are perceived through activation of G protein-coupled chemosensory receptors. In contrast, gustatory detection of salty and sour tastes may involve direct gating of sodium channels of the DEG/ENaC family by sodium and hydrogen ions, respectively. We have found that ppk25, a Drosophila melanogaster gene encoding a DEG/ENaC channel subunit, is expressed at highest levels in the male appendages responsible for gustatory and olfactory detection of female pheromones: the legs, wings, and antennae. Mutations in the ppk25 gene reduce or even abolish male courtship response to females in the dark, …

Aldosterone Stimulates K Secretion Across Mammalian Colon Independent Of Na Absorption, Gerhard Rechkemmer, Dan R. Halm

Neuroscience, Cell Biology & Physiology Faculty Publications

K transport across guinea pig (Cavia porcellus) distal colon was measured in vitro using isotopically determined unidirectional fluxes. Aldosterone stimulated electrogenic Na absorption, as measured by amiloride-sensitive short-circuit current (I_sc), and reduced net K absorption from +2.5 ± 0.2 µEq/cm² per hr to +0.8 ± 0.3 µEq/cm² per hr (mean ± SEM). Amiloride addition to the mucosal solution did not enhance net K absorption, as expected if inhibiting active Na absorption would reduce active K secretion as in the distal nephron. The amiloride-insensitive I_sc was -1.0 ± 0.2 µEq/cm² per hr (mean ± SEM) …