bluuebunny/crossref_metadata_2025 huggingface dataset:
Reversible suppression of mitochondrial respiration in skeletal muscle of the freeze tolerant wood frog Rana Sylvatica
Authors: Hughey Curtis , Shearer Jane , Storey Kenneth B , Hittel Dustin S
Published: June 2021

The wood frog, Rana sylvatica, survives weeks of whole body freezing during our cold Canadian winters through a series of active biochemical adaptations that induce a hypometabolic state. This preserves long‐term viability by reducing metabolic fuel consumption. Given the important contributions of skeletal muscle in general, and mitochondria specifically, to the resting metabolic rate we interrogated muscle mitochondrial function using a combination of high resolution respirometry and fluorescence spectroscopy. We found a dramatic (3–4 fold, P<0.05) decrease in State 2, State 3 (ADP‐stimulated) and uncoupled mitochondrial respiration in‐situ using permeabilized muscle bundles isolated from frozen as compared to unfrozen frogs. This suppression of mitochondrial respiration was completely reversed in thawed animals. The generation of reactive oxygen species (ROS) from muscle mitochondria was similarly suppressed and restored in frozen and thawed animals respectively. The suppression of mitochondrial respiration was not related to changes in mitochondrial content as assessed using citrate synthase or western blot analysis. This study provides the first report of in‐situ mitochondrial respiration in the freeze‐tolerant wood frog, suggesting that mitochondrial regulation is an active part of life extension in hypometabolic states.
Elevated oxygen utilization and superior energetic reserve in superhealer mesenchymal stem cells
Authors: Hughey Curtis C , Alfaro Maria P , Belke Darrell D , Rottman Jeffrey N , Young Pampee P , Wasserman David H , Shearer Jane
Published: June 2021

Objective

Ischemia‐induced death impedes the efficacy of cell‐based therapies in the treatment of a myocardial infarction. Superhealer MRL/MpJ mesenchymal stem cells (MRL‐MSCs) exhibit increased engraftment resulting in reduced infarct size and enhanced contractile function.

Methods and Results

High resolution respirometry was employed to evaluate differences in mitochondrial oxidative phosphorylation that explain the enhanced cellular survival and engraftment of MRL‐MSCs. Compared to wild type MSCs, MRL‐MSCs exhibited an increase in physiological respiration and maximal electron transport capacity by 2.0‐ and 3.5‐fold, respectively. When routine oxygen utilization is expressed as a portion of maximal cellular oxygen flux, the MRL‐MSCs have a greater energetic reserve. Additionally, succinate‐supported oxygen consumption is elevated 1.4‐fold in the MRL‐MSCs.

Conclusion

MRL‐MSCs exhibit a greater reliance on and capacity for aerobic metabolism. These characteristics may diminish cell death upon transplantation into the infarcted heart by increasing ATP synthesis per unit substrate and preventing glycolysis‐mediated acidosis. This work was supported by CIHR, AHFMR, CDA, HSF and NIH Grant [R01‐ HL088424].
Physical host‐pathogen networks
Authors: Krogan Nevan
Published: June 2021

Pathways and complexes can be considered fundamental units of cell biology, but their relationship to each other is difficult to define. Comprehensive tagging and purification experiments have generated networks of interactions that represent most stable protein complexes. We describe this work in various organisms, including budding yeast and in infectious organisms like HIV and TB, and show how the analysis of pairwise epistatic relationships between genes complements the physical interaction data, and furthermore can be used to classify gene products into parallel and linear pathways.
Pro‐inflammatory action of renin‐angiotensin‐aldosterone system (RAAS) in hypothalamic astrocytes from spontaneously hypertensive rats (SHR)
Authors: Rodriguez Vermali , Sumners Colin
Published: June 2021

Over activation of the central RAAS coupled to an enhanced pro‐inflammatory response in the hypothalamic paraventricular nucleus is one of the main contributors to the development and maintenance of neurogenic hypertension. Astrocytes, along with microglia, are key regulators of the central immune response and produce a variety of pro‐inflammatory cytokines including interleukin 6 (IL‐6). Here we demonstrated that incubation of astrocytes purified from the hypothalamus of SHR, a model of neurogenic hypertension, with angiotensin II (Ang II; 100 nM) or aldosterone (ALDO; 100 pM) [both at 3, 6, or 24 h] elicit significantly greater increases in IL‐6 mRNA levels when compared to astrocytes from normotensive rats. Prorenin (PRO; 20 nM) produced similar magnitude increases in IL‐6 mRNA in astrocytes from normotensive rats and SHR, but the effect was more rapid in the latter. Additionally, these RAAS components significantly increased Mas mRNA levels in normotensive rat astrocytes, contrary to their effect in SHR astrocytes, where PRO and ALDO elicited significant decreases in the mRNA for this angiotensin 1–7 (Ang 1–7) receptor. Collectively, these data demonstrate that the pro‐inflammatory actions of RAAS components are enhanced in SHR astrocytes and suggest that there is a reduction in a potential protective mechanism (Ang 1–7/Mas) in these cells in hypertensive rats. Supported by NIH HL‐076803 and HL‐093186.
Leptin acts in the forebrain to increase gain of baroreflex control of lumbar sympathetic nerve activity and heart rate
Authors: Li Baoxin , Cassaglia Priscila A. , Brooks Virginia L.
Published: June 2021

Leptin increases lumbar sympathetic nerve activity (LSNA), but whether leptin also enhances baroreflex control of LSNA and heart rate (HR) is unclear. To test this hypothesis, leptin was infused into the lateral cerebroventricle (ICV) of α‐chloralose anesthetized male SD rats. Baroreflex function was assessed hourly for 2 hrs using a 4 parameter sigmoidal fit of HR and LSNA responses to slow ramp (3–5 min) changes in arterial pressure (AP), induced by iv infusion of nitroprusside and phenylephrine. After 2 hr, leptin (3μg, n=5) increased (P<0.05) the maximum gain (BRG) of LSNA (from 4.0±0.6 to 6.9±1.4 %/mmHg) and HR (from 2.5±0.2 to 3.4±0.5 bpm/mmHg), as well as LSNA (to 204±20 % control), HR (from 327±6 to 395±13 bpm), the reflex LSNA maximum (from 185±12 to 370 ± 38%), the HR maximum (from 399±12 to 472±20 bpm), and mean AP (from 111±3 to124±4 mmHg). A lower dose of leptin (1.5 μg; n=5) transiently increased LSNA BRG at 1 hr (from 3.1±0.6 to 5.5±1.2 %/mmHg; P<0.05); other parameters were not significantly altered. ICV infusion of the artificial CSF vehicle (n=5) had no effects. To test if leptin acts in the brainstem to improve baroreflex function, leptin (3 μg) was infused into the 4th ventricle (n=4). However, no significant changes in LSNA BRG (4.2±0.5 to 4.1±0.5 %/mmHg), HR BRG (2.2 ±0.6 to 2.3±0.5 bpm /mmHg), or other parameters were observed. In conclusion, leptin acts in the forebrain to enhance baroreflex control of HR and LSNA, by increasing BRG and maximum reflex HR and LSNA. Support: HL088552.
Relaxin in the subfornical organ (SFO) increases arterial pressure and lumbar sympathetic nerve activity in female rats: Role of Angiotensin II
Authors: Brown Randall J , Phaup J. Glenn , Hasser Eileen M. , Heesch Cheryl M.
Published: June 2021

Relaxin (RLN), an ovarian hormone secreted in pregnancy, activates the SFO, a circumventricular organ, and regions within the brain parenchyma associated with control of blood volume and sympathetic nerve activity. Previously we demonstrated that intracarotid artery (ica) infusion of RLN (0.154 μM/hr) resulted in activation (increased Fos expression) of both vasopressinergic and spinally projecting neurons in the hypothalamic paraventricular nucleus (PVN). Current experiments in 6 inactin‐anesthetized and sinoaortic‐denervated female rats evaluated effects of acute microinjection of RLN into the SFO on mean arterial pressure (MAP) and efferent lumbar sympathetic nerve activity (LSNA), and a potential interaction with angiotensin II (Ang II). The SFO was functionally identified by pressor (+ 18 ± 3mmHg) and sympathoexcitatory (+ 12 ± 2%) responses to microinjected Ang II (20μM, 50nl). Thirty min. after SFO Ang II, when MAP and LSNA had returned to baseline values, RLN in the SFO (15.4 μM, 50 nl) produced prolonged increases in MAP (+ 27 ± 5mmHg) and LSNA (+ 14 ± 3%). In the presence of RLN‐related pressor effects, ica administration of the AT1 receptor antagonist L158,809 (40 μg/Kg) restored MAP to baseline levels. These data further support a role for CNS actions of RLN in regulating efferent sympathetic nerve activity during pregnancy, likely through Ang II and an SFO‐PVN pathway. NIH RO1 HL091164 (CMH)
Gap junction blockade in the locus coeruleus (LC) decreases the hypercapnic ventilatory response
Authors: Patrone Luis Gustavo A , Bicego Kenia C , Hartzler Lynn , Putnam Robert W , Gargaglioni Luciane H.
Published: June 2021

The LC has an important role in central chemoreception and its contribution decreases with development. In neurons from young rats (P9 or younger), the % of LC neurons that increase firing rate in response to hypercapnia is 85% while it is only about 45% in neurons from rats P10 or older. Carbenoxolone (CARB ‐ gap junction blocker) has very little effect on this response in neurons from the youngest rats, with the % responding dropping only to 70% in the presence of CARB. However, CARB decreases the % responding by half in older animals, dropping it to 21%. We evaluated the participation of gap junctions in the CO2 ventilatory response in conscious adult rats by bilaterally microinjecting CARB (1mM or 3mM / 0.1 μL) or vehicle (artificial cerebrospinal fluid) into the LC of Wistar rats. Bilateral gap junction blockade in LC neurons did not affect resting ventilation. However, the increase in ventilation produced by hypercapnia (7% CO2) was reduced by 20% after CARB injection (1904.5 ± 95.2 in vehicle group vs 1518.0 ± 76.1 mL/kg/min in CARB 3mM group and 1468.3 ± 122.2 mL/kg/min in CARB 1mM) due largely to a decrease in respiratory frequency. The results suggest that gap junctions modulate the hypercapnic ventilatory response, but that they are not involved in respiratory control during normocapnia, in the LC of rats older than P10.

Financial support: INCT‐Fisiologia Comparada, FAPESP, CNPq, and NIH Grant HL56683.
Functional confocal live cell imaging of the pulmonary neuroepithelial body microenvironment in GAD67‐GFP mice
Authors: Schnorbusch Kathy , Brouns Inge , Lembrechts Robrecht , Pintelon Isabel , Timmermans Jean-Pierre , Adriaensen Dirk
Published: June 2021

As integrated components of the airway epithelium, pulmonary neuroepithelial bodies (NEBs), composed of clusters of neuroendocrine cells, are ideally located to sense changes in the airway environment. Connections of NEBs with different populations of mainly vagal sensory nerve terminals allow fast transduction of information to the CNS. NEBs are dispersed in the airway epithelium and inaccessible in vivo. The selective identification of NEBs is a prerequisite to enable functional molecular live cell imaging in our ex vivo lung slice model, but the vital dye 4‐Di‐2‐ASP that we used so far has been criticized. In this study the lung slice model was further strengthened using knock‐in mice that express GFP driven by the promoter of glutamate decarboxylase 67 (GAD67), the rate‐limiting enzyme of GABA synthesis. Highly selective expression of GFP in NEB cells in mouse lungs allows unequivocal selection. Since ex vivo vibratome slices of GAD67‐GFP mouse lungs could be loaded with red‐fluorescent functional probes, and proof‐of‐concept experiments were successful, this model will certainly boost future functional studies of NEBs in health and disease. Simultaneously the model enables to explore the significance of a GABAergic signaling system in the NEB microenvironment.

Support: IWT fellowship SB/81162 (RL); FWO grants G.0081.08 (DA) and G.0589.11N (DA, JPT); UA grants GOA BOF 2007 (DA) and KP BOF 2006 (IB)
Response of the HPA Axis to Intermittent Hypoxia in the Neonatal Rat: ACTH, Corticosterone, and the Expression of Adrenal mRNAs
Authors: Chintamaneni Kathan , Bruder Eric David , Guenther Mitchell Andrew , Raff Hershel
Published: June 2021

Apnea is the temporary cessation of respiratory airflow and is a common cause of intermittent hypoxia (IH) in the premature infant. We hypothesized that IH elicits a stress response in the neonate and alters mRNA expression for critical proteins involved in adrenocortical function. Postnatal day 2 (PD2), PD8, and PD12 rat pups were exposed to 6 cycles of 30 sec of IH (3% O2) over 60 min, and blood samples were obtained at the 3rd (30 min) and 6th (60 min) cycle. Plasma ACTH and corticosterone increased significantly in PD8 and PD12 pups exposed to IH. Interestingly, plasma corticosterone increased in the PD2 pups even though plasma ACTH remained unchanged. Expression of adrenal StAR and Ldlr mRNA increased in PD2 pups exposed to IH, but were not affected in PD8 or PD12 pups. Expression of adrenal Mc2R mRNA decreased in all age groups exposed to IH. IH resulted in profound bradycardia and a decrease in body temperature. We conclude that IH in PD2 pups elicits an adrenocortical response not mediated by ACTH, but associated with an increase in the expression of specific adrenal mRNAs. In PD8 and PD12 pups, the adrenal response is ACTH dependent like an adult. Using the PD2 rat as a model of extreme prematurity in the human, we suggest the existence of a unique non‐ACTH controller of adrenal function during IH.
Utilizing Multi‐Color Flow Cytometry and FACS to Simultaneously Examine Effects of Intermittent Hypoxia on Microglia, Neurons, and Astrocytes
Authors: Smith Stephanie Michelle Crader , Nikodemova Maria , Watters Jyoti J
Published: June 2021

Intermittent Hypoxia (IH) as is experienced during sleep apnea causes significant cortical and hippocampal neuronal apoptosis correlating with a decline in cognition. It is well‐established that neuro‐inflammation underlies much of this neuronal loss, but little is known about the contributing CNS cell types. In the present studies, we exposed rodents to a paradigm of intermittent hypoxia consisting of 8 hours of intermittent hypoxia (2 min 21% O2, 2 min 10.5% O2) or normoxia (21% O2) followed by a 16 hour reoxygenation at room air for either 1, 3, 7, 14, or 28 days. We have developed a multi‐color flow cytometry panel that allows simultaneous examination of protein levels from three distinct CNS cell populations (microglia‐CD11b+, astrocytes‐GFAP+, and neurons‐Neurofilament+) in the cortex and hippocampus, regions of highest neuronal loss after IH. We investigated changes in pro‐inflammatory (TNFα, IL‐1β, iNOS, and COX‐2) and trophic (VEGF, BDNF, IGF‐1) factors. In addition, we utilized markers of apoptosis (Caspase‐3) and proliferation (Ki‐67) to assess neuronal loss and glial proliferation. After this analysis, we utilized Fluorescence‐Activated Cell Sorting (FACS) to sort pure populations of these 3 cell types for gene expression analysis by qRT‐PCR. This powerful technique enables examination of simultaneous, multi‐cellular contributions to IH‐induced neuropathology.
The effects of 7 day exposure to intermittent hypoxia on renal and cervical sympathetic nerve responses to acute hypoxia in rats
Authors: Eubank Wendy , Yamamoto Kenta , Franzke Michelle , Mifflin Steve
Published: June 2021

Intermittent hypoxia (IH) is a widely used model for the repetitive bouts of hypoxia that occur during sleep apnea. Chronic IH enhances cervical sympathetic response to acute hypoxia. We sought to determine if the renal and cervical sympathetic nerve responsiveness to acute hypoxia was enhanced after 7 days exposure to IH. Adult, male Sprague‐Dawley rats (350–500grams) were exposed to IH (9% oxygen for 3min every 10 min, 8 h per day) for 7 days while control rats were maintained in normoxia. Renal and cervical discharge responses to acute hypoxia were determined by reducing fIO2 by N2 inhalation for 10, 15, 20 and 30 sec in anesthetized condition. 7 day IH did not alter the renal sympathetic response to acute hypoxia (n = 4) when compared to the control group (n = 10). Cervical sympathetic response to 20s and 30s hypoxia stimulation were lower in IH group (n = 4) than in control the group (n =10) (renal: 19.9 ± 8.1, 26.2 ± 13.4; vs cervical: 4.3 ± 2.8, 7.7 ± − 4.7, P < 0.05, mean ± S.E.M). These results suggest that 7 days exposure to IH attenuated the cervical sympathetic response to acute hypoxia while the renal sympathetic response was maintained. Supported by HL‐088052
Cerebrovascular Consequences of Obstructive Sleep Apnea
Authors: Crossland Randy F. , Durgan David J. , Lloyd Eric E. , Phillips Sharon C. , Marrelli Sean P. , Bryan Robert M.
Published: June 2021

Obstructive sleep apnea (OSA) is an independent risk factor for stroke. However, little is known about how OSA affects the cerebral circulation. The goal of this project was to test the following hypothesis: Chronic exposure to apnea produces hypertension and alters nitric oxide (NO) mediated dilation in cerebral arteries. For these studies, we developed a novel model of OSA in rats. Airway obstruction was induced by a chronically implanted, inflatable endotracheal obstruction device. We induced 30 apneas (8 sec duration each)/hr during 8 hrs of the sleep cycle in free‐ranging rats. Apnea caused significant alterations in blood gasses [baseline vs. end apnea‐ pO2 (mmHg): 127 ± 2 vs. 67 ± 2; pCO2 (mmHg): 43 ± 1 vs. 51 ± 1; and pH: 7.46 ± 0.002 vs. 7.38 ± 0.01; n=5, p≤0.003]. Apnea decreased hemoglobin O2 saturation by 12 ± 1% (n=5, p=0.001 vs. Sham) and produced exaggerated negative airway pressures (−16 ± 0.7 mmHg; n=7, p<0.001 vs. Sham). Two weeks of apnea produced a 24‐hr mean blood pressure (BP) pattern similar to non‐dipping hypertensives (i.e. ‐ <10% BP dip during the sleep phase). After one month of apnea, NO‐mediated dilations to ATP in isolated cerebral arteries were attenuated by 20 ± 2% (n=4, p<0.02 vs. Sham). Using a novel model of OSA, which recapitulates OSA in humans, we demonstrate that endothelial dysfunction occurs by one month, likely increasing the vulnerability of the brain during stroke.

Funded by NIH R21 HL102778
Foundations of Neurocardiology: Neural control of the normal and diseased heart
Authors: Ardell Jeffrey L.
Published: June 2021

Neurons in the intrinsic cardiac and intrathoracic extracardiac networks of the cardiac neuronal hierarchy form distinct nested feedback loops that act in concert with central feedback loops in the spinal cord, medulla and higher centers to coordinate regional cardiac function. Intrathoracic ganglia contain afferent, local circuit (interneurons) and sympathetic efferent postganglionic neurons. Cardiac‐related parasympathetic efferent postganglionic neurons are confined to intrinsic cardiac ganglia. The peripheral aspects of this hierarchy are, in turn, modulated by central neurons and circulating neurohumoral agents such as Ang II and catecholamines. Imbalances in cardiac neurohumoral control, especially those leading to excessive efferent neuronal activation, can lead to adverse short‐ or long‐term alterations in cardiac function. These involve structural and functional changes within the intrinsic cardiac nervous system, as well as cardiac arrhythmia induction and pump failure. We have proposed that stabilization of imbalances within select elements of the cardiac neuronal hierarchy can i) reduce the arrhythmogenic potential of cardiac tissues and ii) act to maintain myocyte viability in the presence of regional ischemia. Thus, the cardiac neuronal hierarchy has emerged as a novel therapeutic target for managing cardiac disease via pharmacological, physical or electrical means. HL71830
Oxidative stress in hypothalamic neurons may explain the impaired vasopressin secretion observed during sepsis
Authors: Basso Paulo José , Oliveira-Pelegrin Gabriela R. , Rocha Maria José A.
Published: June 2021

Both clinical and experimental studies denoted an impaired vasopressin (VP) secretion in the late phase of sepsis, despite progressive hypotension. One hypothesis to explain this is an excessive production of nitric oxide in the brain, which may induce oxidative stress and apoptosis in vasopressinergic neurons. Our aim was to investigate the occurrence of mitochondrial oxidative stress and apoptosis in magnocellular neurons of the supraoptic nucleus of septic rats.

Male Wistar rats (250±30g) were anesthetized and perfused 24 or 48 hours after cecal ligation puncture (CLP) to induce sepsis, or following sham operation. Brains were removed and processed for immunodetection of hypoxia‐induced factor 1 subunit α (HIF‐1α), Bax, cytochrome‐c (cyt‐c) and cleaved caspase‐3 (casp3), or TUNEL assay.

A granular or punctate staining for cyt‐c and a homogeneous one for Bax was observed in sham rats. These patterns were inversed in some of the septic rats indicating translocation in opposite directions for both proteins with respect to the mitochondria. In these same animals, immunofluorescence for casp‐3 and HIF‐1α reached higher levels compared to sham rats. Additionally, a positive TUNEL staining was observed.

We conclude that sepsis can induce oxidative stress causing apoptosis in hypothalamic magnocellular neurons, which could explain the basal VP levels denoted in the late phase.

Financial support: FAPESP, CAPES.
Thermal stimulation of vasopressin and oxytocin (VP/OT) release from explants of the hypothalamo‐neurohypophyseal system (HNS)
Authors: Sladek Celia D. , Song Zhilin , Stevens Wanida
Published: June 2021

Maintenance of a constant body temperature is essential in homeotherms. Since evaporative heat loss is necessary for preventing hyperthermia, integration of the mechanisms regulating water and thermal homeostasis is required. We used HNS explants from adult rats to study the impact of increases in temperature on stimulation of VP/OT release. Increasing the temperature from 37 to 39.5°C over 1 hr caused a dramatic increase in VP (850%) and OT (405% of basal) release (both p<0.001). Simultaneously exposing explants to a ramp increase in osmolality (25mOsm/2.6 hrs with mannitol) doubled the response to temperature alone (VP‐ 1780%; OT‐860% of basal). Thermal stimulation of VP/OT release was significantly attenuated by combined exposure to gadolinium (100μM), a non‐specific blocker of mechanosensitive channels, and capsazepine (10μM), a selective antagonist of TRPV1 channels, but not by capsazepine alone. This is consistent with other evidence that modified and capsazepine‐insensitive TRPV1 and TRPV4 channels participate in thermal regulation of VP/OT release. The gadolinium/capsazepine resistant response may reflect non‐specific thermal enhancement of metabolic processes. This is further supported by the thermal stimulus causing an increase in VP/OT release from isolated neural lobes similar to that retained by HNS explants in the presence of gadolinium/capsazepine. Supported by NIH RO1 NS‐27975
O‐GlcNAcylation of the AMPA receptor GluA2 Subunit May Contribute to LTD at Hippocampal CA3‐CA1 Synapses
Authors: Wang Kai , Taylor Erica , Marchase Richard , Chatham John , McMahon Lori
Published: June 2021

O‐GlcNAcylation is a dynamic posttranslational modification involving O‐linked addition of β‐N‐acetylglucosamine (GlcNAc) to serine/threonine residues on nucleocytoplasmic proteins. Hippocampal neurons express high levels of OGT and OGA, enzymes that add and remove O‐GlcNAc moieties. Because synaptic function is tightly regulated by serine phosphorylation of synaptic proteins, it is likely that serine O‐GlcNAcylation also regulates synaptic efficacy. We investigated whether increasing O‐GlcNAcylation, with glucosamine or the OGA inhibitor Thiamet‐G, modulates synaptic transmission at CA3‐CA1 synapses in hippocampus, a brain region required for learning and memory. We find that increased O‐GlcNAcylation induces a novel long‐term depression (O‐GlcNAc‐LTD) (85% ± 2.6% and 81% ± 4.1% of baseline, respectively) and causes decrementing long‐term potentiation (control: 135% ± 6.2%, Thiamet‐G: 93% ± 7.1% of baseline). Because PKC‐dependent phosphorylation of Ser‐880 on the AMPAR GluA2 subunit triggers AMPAR endocytosis, we investigated whether GluA2 is O‐GlcNAcylated during O‐GlcNAc LTD, and if this occurs at Ser‐880. Indeed, GluA2, but not GluA1, subunits are O‐GlcNAcylated, without modifying phospho‐Ser‐880 levels. These results suggest that GluA2 O‐GlcNAcylation may contribute to expression of O‐GlcNAc LTD, with a mechanism independent of phospho‐Ser880.
Morphological Changes of the Membranous Labyrinth in Meniereˈs Disease
Authors: Tanioka Hisaya , Kaga Kimitaka
Published: June 2021

Objectives

To image morphological changes of the membranous labyrinth in Meniere's disease using direct volume rendering by temporal bone high‐resolution CT exam. 3D reconstructed images of endolymphatic hydrops with direct volume rendering generate morphological changes in Meniere's disease.

Study Design

In vivo retrospective clinical study during pre‐attack, attack and recovery periods in Meniere's disease.

Patients

Patients with Meniere's disease who were examined at three stages, namely, pre‐attack, attack and recovery period.

Methods

All CT images were acquired on a row CT scanner. The axial data were applied to create 3D volume rendering images on the CT work station for post processing with the factory preset soft ware.

Results

3D images of the membranous labyrinth in Meniere's disease demonstrate different morphologic change in proportion to periods. On attack period, the saccule and utricle was enlargement in comparison with pre‐attack period and recovery period. Patients were treated by increases in vestibular, systematic blood flow and decreases in blood pressure.

Conclusion

We reported the first visualization of endlymphatic hydrops in patients with Meniere's disease that were consistent with periods.
Development and characterization of novel extracellular mimicking blended electrospun scaffolds: effect of scaffold hydrophobicity on endothelial cell growth
Authors: Nosoudi Nasim , Yin Wei , Rubenstein David Alan
Published: June 2021

Electrospinning has been engaged widely in tissue engineering to make scaffolds that aim to mimic specific physical properties of the extracellular matrix (ECM). Here we focused on forming composite scaffolds from pure or blended ethylene‐co‐acrylic acid (EAA), polycaprolactone (PCL), polyethylene oxide (PEO), chitosan and cellulose acetate (CA). Solvent combinations were optimized to maintain stable electrospinning solutions. Scaffold hydrophobicity is a major regulator of adhesion and infiltration and was measured with goniometry. Scanning electron microscopy was used to determine porosity and fiber dimensions. We hypothesized that endothelial cells would prefer scaffolds that were mildly hydrophilic or hydrophobic and that had fiber characteristics similar to the ECM. The average contact angle for PEO, EAA, CA, EAA‐PCL, PCL and chitosan are 38°, 88°, 95°, 103°, 112° and 117°, respectively. Porosity ranged from ~60 to 90%; fiber width ranged from 10nm‐5μm. Endothelial cell viability was highest on scaffolds that were slightly hydrophobic and had larger widths. Thus, hydrophobicity and fiber characteristics play a crucial role in endothelial cell growth on ECM mimicking scaffolds. Thanks to the NIH.
Vascular tortuosity: modeling using optimality analysis
Authors: Hathout Leith , Do Huy
Published: June 2021

Although vascular tortuosity is a ubiquitous phenomenon, very few mathematical models exist to describe its shape. Given that the shape of tortuous vessel curves seems fairly uniform across great variations in anatomic substrata, it is hypothesized that tortuosity is is governed by physical principles. We present a mathematical model of vascular tortuosity based on optimality principles. The model minimizes average curvature per unit length; it produces a “sine‐generated” curve. Thirty‐four tortuous vessel segments are analyzed and compared to the results of the model. Curve shapes are characterized by the parameters L/R and L/λ, where L is curve length, λ is wavelength, and R is radius of curvature. These parameters are measured for each vessel segment and calculated for the corresponding theoretical curves. Comparison between measured and predicted values produces average percent errors of about 6%. This suggests that blood vessels obey optimality principles, and bend in such a way as to minimize average curvature. Vessels from a case of Fabry's disease were also analyzed, and deviated significantly from theoretical results, suggesting that the model can potentially be used to distinguish physiologic curvature from the abnormal tortuosity which occurs in disease states.
Neoblast Markers piwi & vasa Are Expressed During Regeneration and Reproduction in Aeolosoma viride
Authors: Hsieh Yu-Wen , Chu Chia-Ying , Chen Jiun-Hong
Published: June 2021

Some animals can regenerate their lost tissues or organs. Both Tissue remodeling and organ reformation need cell proliferation and/or differentiation during regeneration. Neoblasts, one of the somatic stem cells, can proliferates to increase cell number in invertebrates, such as hydra and planarian. Though hydra and planarian are good model animals for regeneration research, their body plans are too simple to monitor regeneration of highly specific organs. Aeolosoma viride, a fresh water annelid with 19 segments, central nerve system, and a complete digestive system, present great regeneration ability. To trace neoblast, Avpiwi1, Avpiwi2, and Avvasa have been partly cloned. The sequences were used as probes to study A. viride neoblasts. These genes were found to be highly expressed in posterior growth region. Furthermore, Avpiwi1 was also expressed in the regenerating tissue. The expression level of these genes decreased and the regeneration process was blocked after 90 Gy r‐irradiation. These data strongly suggested that Avpiwi1, Avpiwi2, and Avvasa can label the neoblasts, which participate in A. viride regeneration. It means that the function of somatic stem cell may also be conserved in annelids.
Individual craniofacial bone volumes and relative densities in postnatal mice provide valuable phenotypic information
Authors: Percival Christopher , Wang Yingli , Zhou Xueyan , Jabs Ethylin Wang , Richtsmeier Joan T
Published: June 2021

The objective of this study was to develop an efficient method, using Avizo software (VSG), to measure the volume and relative bone mineral density of individual craniofacial bones in early postnatal mice from micro‐computed tomography images. Manually labeled individual bones from representative specimens were expanded to define the theoretical space that a bone would occupy in a standard orientation. These models were transformed into the space of related target specimens and used to identify all voxels above three phantom based on minimum bone density thresholds for each bone of the target specimen. Total bone volumes, medium/high density bone volumes, and ratios of these volumes (relative BMD) were produced for Fgfr2Y394C/+ Beare‐Stevenson cutis gyrata syndrome model mice and unaffected littermates at postnatal day 0 and 8. This provided phenotypic and developmental information unavailable from landmark based morphometrics that can help target regions and developmental times for further analyses. This procedure requires <5% of the time required for manual segmentation. Error levels are acceptable for summary analysis of bone volume and relative density, with higher error for older specimens, smaller bones, and bones surrounding teeth. This work is supported in part by a grant from the National Institute of Dental and Craniofacial Research to JTR (R01‐DE018500, ‐DE18500‐S1, ‐DE18500‐S2).

Grant Funding Source: National Institute of Dental and Craniofacial Research
Esrp1 and Esrp2 expression in the developing midface and kidney of mice with frontonasal dysplasia and renal hypoplasia
Authors: Hong Trudy , Hynd Thomas , Lozanoff Scott
Published: June 2021

The Brachyrrhine (Br) mutant mouse displays heritable frontonasal dysplasia (FND) and renal hypoplasia (RH). Previous DNA microarray analysis on embryonic Br facial explants showed a misexpression of several genes, two of which are Esrp1 and Esrp2. Together, the Esrp genes play an essential role in the regulation of epithelial‐mesenchymal transition—an important process in craniofacial and kidney development. The primary objective of this study is to determine if Esrp1 and ‐2 contributes to a developmental pathway leading to FND or RH in the Br mouse and, specifically, if there is a difference in Esrp1 and ‐2 expression in the developing midface and kidneys of wild type (WT) and Br adults and embryos. WT and Br/Br E11.5 medial nasal prominences (MNP) and E15.5 and E18.5 kidneys were dissected and RNA extracted for qPCR expression analysis. Preliminary results show minimal difference in Esrp1 and ‐2 expression in MNPs of WT and Br embryos, and an increase in Esrp2 expression from E15.5 to E18.5 WT kidneys. Future work involving qPCR and immunohistochemistry will be completed to better understand the expression patterns of these two genes. Results from this study will contribute to our understanding of the genetic basis of craniofacial and kidney morphogenesis.

Grant Funding Source: 1R01‐DK‐064752 (SL)
FGF signaling specifies pre‐chondrogenic identity in neural crest derived mesenchyme, but initiation of chondrogenesis requires BMP4 signaling
Authors: Kumar Megha , Ray Poulomi , Chapman Susan C.
Published: June 2021

The chick middle ear bone, columella, derives from neural crest mesenchyme located proximally in the second pharyngeal arch. Subjacent pharyngeal endoderm is hypothesized as the source of the local signals that specify the pre‐chondrogenic identity of this tissue. Sox9 is induced and maintained in pre‐chondrogenic cells during condensation formation and endochondral ossification. We show that pharyngeal endoderm was sufficient, but not necessary for specifying pre‐chondrogenic identity. Many Fgf genes are expressed specifically in the pharyngeal endoderm subjacent to neural crest derived mesenchyme. Our results show that FGF signaling is both sufficient and required for specification of Sox9 expression and specification of pre‐chondrogenic identity. Further, FGF signaling, by itself, is insufficient for the induction of the chondrogenic marker, Col2a1. BMP4 signaling can induce Sox9 expression, but only in combination with FGF signaling induced Col2a1 expression and, thus, chondrogenesis. Given the spatio‐temporal expression patterns of FGFs and BMPs in the pharyngeal arches, we suggest that this may represent a general mechanism of specifying pre‐chondrogenic identity and chondrogenesis.

Grant Funding Source: NIH/NIDCD
Mesenchymal condensation sets the stage for intramembranous bone development
Authors: Jabalee James , Franz-Odendaal Tamara
Published: June 2021

Mesenchymal condensation is one of the earliest, and most critical, stages in the formation of intramembranous (directly ossifying) bone. It is during the condensation phase that key skeletogenic genes are first upregulated and during which collagen I, the scaffold on which the inorganic portion of bone will be deposited, is first established. Thus, morphogenesis and tissue specific gene expression occur concurrently. Previously, we used microarray analysis and in situ hybridisation to determine which genes are important and at what stage of development these genes act during intramembranous ossification in chick and zebrafish. In the current study, we utilize a combination of light and electron microscopy to better understand the patterning and polarization of cells in early skeletogenic condensations. We compare neural crest derived intramembranous bones, specifically the scleral ossicles of the chick (Gallus gallus) and the opercula of the zebrafish (Danio rerio). While our preliminary results in the chick suggest osteoblasts are polarized toward the center of the early condensations, more data is required to make a solid conclusion. Data collection in zebrafish is also ongoing. Combined, these studies provide a means to correlate gene expression and morphogenesis during intramembranous bone formation.

Grant Funding Source : Nova Scotia Health Research Foundation (Canada) ; Natural Sciences and Engineering Research Council of Canada
The expression pattern of echinoderm microtubule‐associated like proteins (EMLs) in zebrafish during caudal tail regeneration
Authors: Dyer William C. , Daggett Melissa A. F.
Published: June 2021

Cells are comprised of three major cytoskeletal filaments; microtubules, microfilaments, and intermediate filaments. Proteins are known to associate with these filaments and ultimately help to carry out the filament's respective function. Microtubules in particular carry out essential functions such as chromosome segregation during cell division. A conserved family of proteins referred to as echinoderm microtubule‐associated like proteins (EMLs) has been identified in the genomes of a wide range of phyla. The original EML family member, the 77 kD echinoderm microtubule‐associated protein (EMAP), was characterized in sea urchin eggs and embryos where it is found on the mitotic spindle and co‐localizes with protein kinases important for cell‐cycle regulation. PCR analysis of cDNA isolated from zebrafish tissues indicates the presence of EML transcripts in zebrafish during all stages of development and in adult tissues including the caudal tail. The goal of this study is to investigate the expression pattern of the zebrafish EML homologs using a caudal tail regeneration system. Our results indicate that the expression of both zebrafish EML homologs goes down during caudal tail regeneration.
Cardiac Changes In Fetal Mice From Tap Water Exposure
Authors: Hrubec Terry C , Melin Travis , Reinoso Valerie P , Gutierrez J Claudio
Published: June 2021

In 2006, we began to observe neural tube defects, cleft palates and rib malformations in mice exposed to an unidentified teratogen present in the water. Providing distilled deionized (DDI) water decreased or eliminated malformations while providing water from different municipalities induced malformations. We wanted to examine the effect of this unidentified teratogen on heart development. Mice were exposed to tap water or DDI water for 8 weeks prior to breeding and throughout gestation. Fetuses were examined on day 17 of gestation and processed for histopathological evaluation. Changes in cardiac development were assessed from digital images of serial sections taken at standardized levels in the thorax. Parametric and non‐parametric statistical analysis was performed on 13 morphological measurements to compare difference between treatments (P<0.05). Exposure to tap water significantly increased total myocardial area, interventricular septal area, left myocardial area, aortic valve area, and ascending transverse aortic diameter. Right ventricular chamber area significantly decreased with tap water exposure possibly due to enlargement of the left ventricular myocardium. Collectively these changes indicate a left sided hypertrophic cardiomyopathy in day 17 tap water exposed mouse fetuses. Funded by the Harvey Peters Foundation and the VA‐MD Regional College of Veterinary Medicine.
Embryonic transcription factor upregulation during normal lactation and breast oncogenesis
Authors: Hassiotou Foteini , Beltran Adriana , Trengove Naomi , Lai Ching Tat , Hartmann Peter , Filgueira Luis , Blancafort Pilar
Published: June 2021

In addition to their physiological role during pregnancy/lactation, mammary stem cells (MaSCs) are primary targets of malignant transformation, giving rise to invasive breast carcinomas. To pinpoint the molecular switches that transform these cells, we must understand the basic machinery that controls their self‐renewal. We non‐invasively accessed lactation‐associated MaSCs via breastmilk. A cell population was identified expressing the pluripotency transcription factors (TFs) Oct4, Sox2 and Nanog, which generated monolayers and spheroids in 2D and 3D culture, respectively, expressing these TFs. Culture in differentiation conditions resulted in differentiation into cells originating from the three germ layers. Examination of normal resting and lactating human breast tissues revealed that these TFs are upregulated during lactation. Lentivirally‐transduced Oct4‐overexpressing mammary cells from the resting gland bypassed cellular senescence and generated subcutaneous tumors with colonization capabilities when injected in nude mice. Examination of different types of breast tumors showed expression of these TFs only in invasive basal tumors with lactating features. It is concluded that these embryonic TFs play important regulatory roles in the normal expansion of the breast during pregnancy/lactation, but also act as oncogenic targets in certain types of breast cancers.

Grant Funding Source : Women and Infants Research Foundation (FH); Medela AG (PH); 1R01CA125273 and 3R01CA125273‐03S1 and Department of Defence grant W81XWH‐10‐1‐0265 (PB)
Cell fusion phenomena was detected after xenogenic intra‐uterus transplantation of Ds‐red porcine amniotic fluid derived stem cells into EGFP bearing mice
Authors: peng shao-yu , Chou Chih-Jen , Wu Shinn-Chih
Published: June 2021

Amniotic fluid derived stem cells (AFSCs) are derived from amniotic fluid of developing fetus and can be given rise to three germ layers ‐ endoderm, mesoderm and ectoderm. Intra‐uterus transplantation (IUT) is an approach to cure the inherited genetic defect for the fetus during the gestation period of the pregnant female. Certain diseases such as osteogenesis imperfect, muscular destrophy, ect. were successfully treated with stem cells to ameliorate the syndrome. The purpose of this study was to investigate the bio‐distribution and engraftment of porcine amniotic fluid derived stem cell (pAFSCs) after IUT and further determine the fate of the donor cells through Ds‐red harboring pAFSCs inject into EGFP‐harboring fetus of the pregnant mice. The 12.5 days pregnant mice were performed the IUT surgery by pAFSCs injection. One month after birth, the mice were sacrificed. Several portions from different organs were sampled for histological examination. Experiment results showed that the migration of Ds‐red pAFSCs were expressed most significantly in the intestines. Furthermore, the EGFP signal and RFP signal were co‐expressed in the detected cells. It is concluded that the exogenous implantation of pAFSC was fused with recipient cells instead of differentiation or maintain the undifferentiated status retaining in the tissue.

Grant Funding Source : National Taiwan University
Using neural stem cells as an anti‐cancer drug delivery vehicle for treating human breast cancer
Authors: Reuter Ashley , Davis Kelsey , Rachakatla Raja Shekar
Published: June 2021

The broad, long‐term objective of this lab was to use C 17.2 murine neural stem cells (NSC) as a targeted, drug delivery vehicle to treat tumors. Our goal was to determine if NSC can be used as a drug delivery vehicle to administer interferon beta (IFN‐β) directly to MDA 231 human breast cancer and to look at the therapeutic ability of NSC transduced with IFN‐β (NSC‐IFN‐β) on MDA 231 cells. We addressed two specific aims. Specific aim 1 determined if NSC migrate towards MDA 231 cells in vitro. A transwell plate was seeded with selected concentrations of MDA 231 cells in the lower chambers and NSC in the upper chambers. After 24 hours, the migrated NSC were counted using confocal microscopy.

Results

There was a significant increase (P<0.001) of NSC migration towards 10,000 and 100,000 MDA 231 cells compared to control. Specific aim 2 determined if NSC‐IFN‐β migrate towards and kill MDA 231 cancer cells in vitro. A transwell plate was seeded with MDA 231 cells in the lower chambers and NSC (control) or NSC‐IFN‐β in the upper chambers. After 48 hours, the live and dead cells were counted.

Results

The number of live cells significantly decreased (P<0.001) when using NSC‐IFN‐β compared to control.

Conclusion

NSC and NSC‐IFN‐β migrate towards MDA 231 human breast cancer and NSC‐IFN‐β significantly reduced the number of cancer cells. Future studies include testing NSC‐IFN‐β efficacy on human breast cancer in vivo.

Grant Funding Source : A. T. Still University Graduate Program
Effects of Mesterolone on satellite cell distribution and myonuclear number in maturing skeletal muscle fibers
Authors: Allouh Mohammed Zohair , Aldirawi Mohammed Hasan
Published: June 2021

Mesterolone is a synthetic oral anabolic steroid usually used to treat hypogonadism. Mesterolone abuse has been frequently reported in human and equine sports, in which it is used to increase muscle mass and strength. However, little is known about the effects of mesterolone on satellite cells (SCs), which permit muscle growth by forming new myonuclei. This study tests the hypothesis that mesterolone induced muscle hypertrophy is associated with an increase in the number of SCs. Using immunocytochemical techniques and morphometric analyses, fiber size and numbers of SCs and myonuclei in the pectoralis muscle of maturing chickens were quantified. Mesterolone significantly increased fiber size by approximately 36% (P<0.01). In addition, numbers of SCs and myonuclei were significantly increased by mesterolone administration (P<0.01). These results demonstrate that mesterolone‐induced skeletal muscle hypertrophy is associated with increased numbers of SCs during maturation. Funds for this study were provided by a grant from the Deanship of Research at Jordan University of Science & Technology (25/2010).

Grant Funding Source: Deanship of Research, JUST
Acute Inhibition of Connexin43 Expression Promotes Vesicant Wound Repair in a Nitrogen Mustard Induced Hairless Mouse Cutaneous Injury Model
Authors: Chang Yoke-Chen , Wang James D , Hahn Rita A , Gordon Marion K , Gerecke Donald R
Published: June 2021

The gap‐junction proteins, the connexins, mediate intercellular communication and play a significant regulatory role in wound repairs. Recent studies showed that transient inhibition of connexin43 (Cx43) expression resulted in accelerated wound healing in both incisional and burn skin wounds. Skin wounds caused by vesicants generally result in an acute immune response and delayed wound repairs. We tested Cx43 antisense oligodeoxynucleotides (asODN) in a time course study of SKH‐1 mouse skin injury induced by the vesicant, nitrogen mustard, to observe the wound repair response. Animals treated with asODN had a significantly improved survival rate after 10 days when compared to all other control groups. Histological examination of tissue sections showed less acute inflammation for the asODN treated group when compared to the control groups. RT‐PCR and Western blot analysis showed a reduction of Cx43 for days 1 and 3. Cx 26 and 30 were also reduced at days 1 and 3 as shown by RT‐PCR. IL1B, the proinflammatory cytokine is five times less in the asODN samples compared to NM alone. IL10, the anti‐inflammatory cytokine is three fold higher compared to NM alone at three days post exposure. Macrophage elastase decreased at days 7 and 10 when compared to NM alone. This suggests Cx43 is essential to wound repair signaling. The potential use of Cx43 asODN helped reduction in secondary damage and a promotion of vesicant wound repair.

Grant Funding Source: ES005022, ES004738, EY09056, and NIAMS U54AR055073