bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dorsal spinal cord stimulation obtunds the capacity of intrathoracic extracardiac neurons to transduce myocardial ischemia
Authors: Ardell Jeffrey L. , Cardinal René , Vermeulen Michel , Armour J. Andrew 
Published: June 2021

Populations of intrathoracic extracardiac neurons transduce myocardial ischemia, thereby contributing to sympathetic control of regional cardiac indices during such pathology. Our objective was to determine whether electrical neuromodulation using spinal cord stimulation (SCS) modulates such local reflex control.MethodsIn 10 anesthetized canines, middle cervical ganglion neurons were identified that transduce the ventricular milieu. Their capacity to transduce a global (rapid ventricular pacing) versus regional (transient regional ischemia) ventricular stress was tested before and after SCS (50 Hz, 0.2 msec duration at 90% motor threshold) applied to the dorsal, cranial thoracic spinal cord. Rapid ventricular pacing and transient myocardial ischemia both activated cardiac related middle cervical ganglion neurons. SCS obtunded their capacity to reflexly respond to the regional ventricular ischemia, but not rapid ventricular pacing.ConclusionsSpinal cord inputs to the intrathoracic extracardiac nervous system obtund the latter's capacity to transduce regional ventricular ischemia, but not global cardiac stress. Given the substantial body of literature indicating the adverse consequences of excessive adrenergic neuronal excitation on cardiac function, these data delineate the intrathoracic extracardiac nervous system as a potential target for neuromodulation therapy in minimizing such effects. (Supported by HL71830)
Crystallographic and genetic studies of archaeal RNA polymerase
Authors: Murakami Katsu 
Published: June 2021

The transcription apparatus in Archaea can be described as a simplified version of its eukaryotic RNA polymerase (RNAP) II (Pol II) counterpart. We reported the first crystal structure of the archaeal RNAP from Sulfolobus solfataricus at 3.4 ? resolution, completing the suite of multi‐subunit RNAP structures from all three domains of life (Hirata et al, Nature 2008). We also reported the high resolution (at 1.76 Å) crystal structure of the D/L subcomplex of archaeal RNAP and provide the first experimental evidence of any RNAP possessing an iron‐sulfur (Fe‐S) cluster, which plays a structural role in a key subunit of RNAP assembly. Our analysis of RNAP structures provides insight into the derivation of the cellular RNAPs from their common ancestor. In addition, the striking structural similarity between archaeal RNAP and eukaryotic Pol II highlights the simpler archaeal RNAP as an ideal model system for dissecting the molecular basis of eukaryotic transcription.All archaeal genomes encode RNAP subunits E and F (encoded by rpoE and rpoF) that share a common ancestry with the Pol II subunits Rpb7 and Rpb4. By gene replacement, we have isolated the ΔrpoF Thermococcus kodakarensis cells that grew at the same rate as wild‐type at 70 °C, but much slower and to lower cell densities at 85 °C. RNAP preparations purified from ΔrpoF cells lacked subunit F and also subunit E and a transcription factor TFE that co‐purifies with RNAP from wild‐type cells, but in vitro, this mutant RNAP exhibited no discernible differences from wild‐type RNAP in promoter‐dependent transcription, abortive transcript synthesis, transcript elongation or termination (Hirata et al, Mol. Microbiol. 2008).
Changes of heat shock protein 70, intracellular Ca2+, NO and free radicals in epilepsy rat brain tissues affected by garoderma lucidum spores
Authors: Wang Shu‐Qiu , Kang Yu‐Ming , Liu Lei , Ma Xiao‐Ru , Wang Xian‐Gang , Chen Ting‐Yu , Zhang Dong‐Dong , Liang Yan‐Feng , Zhang Bo 
Published: June 2021

To investigate the effects of garoderma lucidum spores on the change of heat shock protein 70 (HSP70), intracellular Ca2+, NO and NOS content in epilepsy rats brain tissues. Thirty male Wistar rats at the age of 10 weeks were divided into garoderma lucidum spores group, epilepsy model group and blank control group. The result showed that NOS, NO and intracellular Ca2+ in brain tissue of garoderma lucidum spores group were significantly lower than in epilepsy model group. The number of HSP70 positive cells was more in garoderma lucidum spores group, while there was no expression in blank contrast group.ConclusionBy effectively reducing the Ca2+ overload of neuron cell, reducing the formation and harm of NO and free radicals, and enhancing the expression of HSP70 in brain tissue, garoderma lucidum spores can weaken the damage to nerve system caused by continuous epileptic seizure.
Serotonin Regulation by Astrocytes
Authors: Watson Cheryl , Bates Jonatha , Franczak Rod 
Published: June 2021

The concentration of serotonin in synaptic spaces is regulated by serotonergic neurons through a cycle of serotonin synthesis and vesicular packaging via vesicular monoamine transporter (VMAT), release, reuptake via serotonin reuptake transporter (SERT), degradation via monoamine oxidase (MAO), and repackaging in vesicles. Astrocytes are also known to contribute to the regulation of synaptic serotonin concentration through uptake of serotonin via SERT, and the subsequent degradation by MAO. Our question was: can astrocytes also package serotonin into vesicles and release it in response to a physiological signal?Astrocytes were dissociated from 1‐3 day old rat pups and cultured. Astrocytes were then exposed to 0.3 µM‐ 100 uM serotonin for 5 hours. Immunofluorescent experiments on serotonin loaded, GFAP positive astrocytes, show an uptake of serotonin into discrete clusters which co‐localize with the VMAT protein. This localization may be due to packaging in vesicles, which is suggested by the presence of VMAT. Western blot and RT‐PCR experiments show the presence of VMAT message and protein in astrocytes. During exocytosis assays serotonin is released from astrocytes into the surrounding media, in response to a treatment with 100 uM ATP. Serotonin uptake can be inhibited by SSRI's such as fluoxetine and citalopram. These results suggest that astrocytes may be capable of packaging serotonin after reuptake, and releasing it in response to a physiological signal.
EXERCISE‐INDUCED PLASTICITY IN THE RAT HIPPOCAMPUS, MOTOR CORTEX AND BRAIN STEM
Authors: Ferreira Ana FB , Real Caroline , Alves Adilson S , Britto Luiz RG , Filosa Jessica A 
Published: June 2021

Increasing evidence shows that physical exercise is neuroprotective and enhances brain function by improving memory, cognitive functions, neuroplasticity, and learning. The aim of this study was to observe the plastic effects physical exercise has on regions of the CNS related to cognitive and motor functions by evaluating the expression of structural proteins. A group of 40 adult male Wistar rats were subjected to an exercise protocol on an adapted treadmill. Following a 2 day adaptation period, the exercised group ran for 40 min/day, at 0.6km/h for 3 (3D), 7 (7D) or 15 (15D) days. At the end of the exercise protocol, brains were subjected to immunoblotting analysis to evaluate the expression of neurofilaments (NF) in the hippocampus, motor cortex and brain stem. In the hippocampus, immunoblot analysis showed increased expression of NF68 (p<0.005) following 3D exercise. In the motor cortex, however, the levels of both NF68 and NF160 decreased (p<0.05) after 3D exercised and increased at 15D for NF68 (p<0.05). The brain stem showed increased expression of all NFs at 15D (p<0.05). These results suggest that physical exercise alters the expression of structural neuronal proteins in brain regions associated with motor control, cognition, memory and learning. Our current ongoing studies focuses on the functional role astrocytes have on exercise‐induced structural neuronal changes.Support: FAPESP, CNPq, CAPES
Ambient glutamate levels under astrocytic control enhance excitability of supraoptic nucleus (SON) neurons. An in vitro and in vivo study
Authors: Fleming Tiffany Marie , Scott Victoria , Brown Colin H. , Stern Javier E 
Published: June 2021

In addition to mediating conventional quantal synaptic transmission, glutamate (GLU) mediates a persistent, tonic form of excitation (GLUtonic) mediated by NMDA receptors. Here, we aimed to determine 1) if ambient GLU tonically activates NMDARs in SON neurons 2) the role of astrocytes in regulating GLUtonic 3) the functional relevance of GLUtonic and 4) if GLUtonic is altered in dehydration (48DH). In electrophysiological recordings obtained from hypothalamic slices, the NMDA receptor antagonist D‐AP5 blocked a tonic inward current of 54.0. ±2.4 pA, a proportion of which (35.3%) was sensitive to the NR2B subunit selective blocker ifenprodil. Blockade of the glial glutamate transporter GLT‐1 by dihydrokainate (DHK) increased GLUtonic (23.3 pA ± 2.0 pA, n = 7, P < 0.01) but effects were blunted in 48DH rats (13.5 pA ± 1.0 pA, n = 5). In single‐unit extracellular recordings obtained from SON neurons in vivo, firing rate was higher in 48DH rats (10.5 ± 2.1 Hz, n = 12, P<0.01) than in controls (4.2 ± 0.6 Hz, n = 11). Microdialysis administration of DHK increased SON neuron firing rate (by 121.7 ± 31.3%, n = 7, P < 0.02) in controls, but not in 48DH rats (4.3 ± 7.3%, n = 4). Our results support that by controlling ambient GLU levels, SON astrocytes regulate GLUtonic and SON neuronal activity, a function that is diminished during dehydration. Ongoing experiments assess the effects of GLUtonic on SON somatodendritic VP and OT release.Supported by NIH RO1HL68725 , NIH R01HL090948‐01, the Otago School of Medical Sciences Bequest Fund, NSF EAPSI.
Infarct rupture and cardiac remodeling after myocardial infarction in 5 different mouse strains
Authors: Janssen Ben , van de Borne Susanne , Brouns‐Strzelecka Agnieszka , Hermans Rob , Blankesteijn Matthijs 
Published: June 2021

BackgroundTransgenic mouse models are used extensively to study the process of infarct healing. However, genetic background may affect the outcome of such studies.MethodsWe compared in 5 different mouse strains (BalbC, C57Bl6, FVB, 129S6 and Swiss) the process of infarct healing after myocardial infarction (MI). Cardiac dimensions were monitored by echocardiography and histology. Cardiac function was determined by intraventricular pressure measurements.ResultsThe area at risk was not different between mouse strains. Infarct rupture, which occurred 3‐6 days post‐MI, was most frequent in 129S6 (62%), followed by C57Bl6 (31%), FVB (24%), Swiss (15%) and FVB (3%). This frequency correlated strongly with systolic pressures at 3 days post‐MI, number of inflammatory cells and MMP‐9 activity. Acute heart failure was observed in 25% of FVB mice in the first week after MI, but was rare in other groups. Cardiac dilatation was most marked in Swiss mice and least prominent in surviving 129S6. The dilatation correlated positively with dP/dt values at 14 and 28 days post‐MI. Secondary thinning of the infarct area between 14 and 28 days post‐MI was marked in BalbC (385±55 to 262±26 μm), FVB (480±128 to 300±49 μm) and Swiss (498±135 to 333±72 μm, all P<0.05), but absent in C57Bl6 (409±55 to 402±32 μm) and 129S6 (517±103 to 484±47 µm). This was paralleled by the highest amounts of alpha‐smooth muscle actin positive fibroblasts, so‐called myofibroblasts, in the latter two groups.ConclusionsInfarct healing in mice strongly depends on genetic background. For studies on the prevention of infarct rupture, 129S6 is the background of choice, whereas BalbC, FVB and Swiss are best suited to study infarct dilatation. The amount of myofibroblasts at 14 days post‐MI predicts the secondary dilatation of the infarct.
O‐GlcNAc Transferase Deficiency Exacerbates Metabolic Defects in the Failing Heart
Authors: Watson Lewis Joshua , Facundo Heberty T , Ngoh Gladys , Jones Steven 
Published: June 2021

The peroxisome proliferator activated receptor gamma coactivator‐1alpha (PGC‐1α) is a transcriptional activator of many metabolic genes, especially those used in the metabolism of fatty acids. Within the failing heart, a metabolic shift occurs from utilizing mainly fatty acids to relying more on glycolysis. Concurrent with this shift is a reduction in the expression of PGC‐1α and an increase in the glucose‐derived, metabolic post‐translational modification O‐GlcNAc. We hypothesized that O‐GlcNAc signaling would play a role in the control of PGC‐1α during this metabolic change. We subjected wild‐type mice to coronary ligation (HF) or sham. After five days both PGC‐1α and PGC‐1 α levels were significantly reduced (p<0.05) and O‐GlcNAc levels significantly elevated (p<0.05). Using the MerCreMer transgene system coupled with a loxP‐flanked OGT mouse, a cardiomyocyte specific OGT 'KO' was made. After tamoxifen induction, cardiac OGT and O‐GlcNAc levels were significantly reduced (p<0.05) in the transgenic (Tg) group. NTg and Tg mice underwent HF or sham surgery and tissues were harvested after 5 days. Following HF, Tg mice exhibited a greater reduction in PGC levels (figure A, p>0.05) than their NTg counterparts. We conclude that ablation of OGT exacerbates the suppression of PGC‐1α in the failing heart.Funded by the NIH and American Heart Association.
Fatty acid beta oxidation is the source of malonyl‐CoA for fatty acid chain elongation in rat heart
Authors: Kerner Janos , Minkler Paul , Stoll Maria , Hoppel Charles 
Published: June 2021

In rat hearts perfused with [16,16,16‐d3]palmitic acid (M+3), some of the perfused palmitate underwent chain elongation to form M+3 stearoylcarnitine. No M+5 stearoylcarnitine was found indicating that unlabeled malonyl‐CoA served as the chain extender. Based on our data that peroxisomal fatty acid oxidation is the source of carbon units for malonyl‐CoA, in follow‐up experiments we asked whether fatty acid β‐oxidation of palmitate accounted for the chain elongation. Rat hearts were perfused in the working mode with [1,2,3,4‐13C4]palmitic acid (M+4) and the isotopic patterns analyzed using LC/MS/MS and a newly available algorithm. The presence of myristoylcarnitine with M+2 provides evidence for β‐oxidation of perfused M+4 palmitic acid. The relative amount of this mass isotopomer accounts for 82.5%. On the other hand, the 72% relative amount of M+4 species in stearoylcarnitine (corrected by the 21% relative amount of unlabeled, M+0 species) clearly shows that a significant fraction of the perfused palmitate was chain elongated. In addition to M+4 species, there also was a significant amount of M+6 stearoylcarnitine (22% corrected by the M+0 species). The formation of M+6 stearoylcarnitine can be explained only by β‐oxidation of the perfused palmitate and conversion of the M+2 acetyl‐CoA to M+2 malonyl‐CoA which serves as the acceptor for M+4 palmitoyl‐CoA.Supported by: DK‐066107 and POI AG15885.
Antioxidant status in different genetic strains of rats subjected to severe hemorrhage
Authors: Dubick Michael A , Barr Johnny L , Klemcke Harold G 
Published: June 2021

Previous studies in our laboratory demonstrated an 8‐fold difference in survival time after hemorrhage among several rat strains (Klemcke et al., 2008). The present study evaluated whether antioxidant status among strains was associated with these differences. Lung, liver, small intestine and brain were collected 30 min after hemorrhage or handling from 3 groups (control, sham hemorrhage and hemorrhage, n=5/gp) of 3 inbred rats strains (Brown Norway (BN), Fawn Hooded Hypertensive (FHH) and DA) divergent in survival time after hemorrhage (BN>FHH>DA). Tissues were analyzed for antioxidant potential, thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), and antioxidant enzyme activities (GSH‐reductase, GSH‐peroxidase, and catalase). For control rats of each strain, these variables were similar when the same tissue was compared. BN rats appeared more responsive to catheterization (sham) and hemorrhage than the other strains, with decreases in brain TBARS, GSH, nitric oxide and lung antioxidant potential compared to controls. For each tissue, as there were no differences between shams and hemorrhage groups, these changes in BN rats did not appear to be related to the hemorrhage. At the time point measured, these data suggest that these rat strains had similar antioxidant status and there were few hemorrhage associated changes in antioxidant levels.Supported by US Army MRMC.
Evidence for Connexin Hemichannel Activity in Porcine Ocular Nonpigmented Ciliary Epithelium
Authors: Shahidullah Mohammad , Delamere Nicholas A 
Published: June 2021

ObjectiveRecent studies have shown that unpaired connexons form active hemichannels connecting the cytoplasm to the extracellular space. In porcine ciliary body we detected connexin 50 (Cx 50) at the aqueous humor (AH)‐facing basolateral surface and connexin 43 at the apical surface of nonpigmented ciliary epithelium (NPE).MethodsConnexins were detected by immunological study. To probe for hemichannel activity, cells were cultured on permeable inserts and incubated with the DNA intercalating agent propidium iodide (PI) (Mol. wt. 668.4) or fluorescein dextran (FDex) (Mol. wt 4000), both of which are membrane impermeable. PI or FDex was detected by fluorescence microscopy and fluorimetry.ResultsUnder control conditions, only traces of PI entered cultured NPE. PI entry was markedly increased in cells incubated with calcium‐free buffer. FDex did not enter the cultured NPE either in control or calcium‐free medium, indicating size‐limited entry. PI entry also was dependent on [pH]o; significantly higher at pH 7.6 than at pH 7.4 or lower. PI uptake was inhibited by a gap‐junction‐specific blocker 18[alpha] glycyrrhetinic acid (100 [mu]M).ConclusionsThe findings are consistent with the ability of NPE cells to form functional hemichannels. Since Cx 50 is localized to the unapposed basolateral surface of the NPE, we suggest it may act as a hemichannel conduit between the cytoplasm and the AH. EY006915
Multi‐drug resistance (MDR1) gene identification and sequence in horses
Authors: Linardi Renata L , Natalini Claudio C , Kousoulas Konstantin G , Huang Li Ju Ti , Stokes Ashley Michelle , Moore Rustin M 
Published: June 2021

P‐glycoprotein (P‐gp), a membrane transporter encoded in the multi‐drug resistance (MDR1) gene, has been identified in many species but not in equine. P‐gp interferes with bioavailability and disposition of many drugs and may explain adverse drug‐induced effects after intravenous administration and poor response with oral administration.The hypothesis is that the MDR1 gene is present in horses. We identified the presence of the equine MDR1 gene, obtained the gene sequence and detected its presence in normal equine tissues.To identify the equine MDR1 gene, total RNA was extracted from intestinal samples, was reverse transcribed to cDNA and used as a template for PCR. Primers were designed by MacVector 65.3 software using the Gen Bank AY360144 MDR1 cDNA rabbit sequence. Real Time TaqMan RT‐PCR was used to detect the presence of MDR1 gene in the intestine, brain, and spinal cord from six horses.Our sequence was compared to the MDR1 rabbit sequence and the horse partial MDR1 sequence demonstrated high similarity with this (84%) and other species. Our RT‐PCR data confirmed the presence of the MDR1 gene in the intestine, brain, and spinal cord of all 6 horses.This data may improve pharmacokinetic and pharmacodynamic studies since the presence of this gene may predispose horses to differences in enteric absorption of some therapeutic agents.Funding provided by the LSU Equine Health Studies Program.
Luminal adenosine signaling regulates duodenal bicarbonate secretion via A2B receptor and CFTR in rats
Authors: Akiba Yasutada , Ham Maggie , Watanabe Chikako , Nakano Takanari , Kaunitz Jonathan D 
Published: June 2021

Duodenal bicarbonate secretion (DBS) is increased by luminal ATP, via activation of enterocyte brush border P2Y1 receptors. Increased DBS augments the activity of intestinal alkaline phosphatase (IAP) activity, which degrades luminal ATP, acting as a negative feedback loop. Since IAP dephosphorylates ATP to ADP, AMP, and adenosine (ADO), and since adenosine deaminase (ADA) is highly expressed in duodenal brush border, we hypothesized that luminal ADO signaling is also involved in DBS regulation.We measured DBS with flow‐through pH and CO2 electrodes, testing the effect of perfusion of ATP, ADP, AMP or ADO with or without adenosine receptor (A1‐3R) agonists or antagonists, or CFTR inhibitor CFTRinh‐172 on DBS. We also examined the effect of inhibitors of ADA or concentrative nucleoside transporter (CNT) on DBS.Perfusion of ATP, ADP, AMP or ADO uniformly increased DBS. A2BR agonist NECA increased DBS, whereas ADO‐augmented DBS was inhibited by A2BR antagonist MRS1754 and abolished by CFTRinh‐172. Other AR agonists or antagonists had no effect. A2BR was immunolocalized to the brush border of duodenal villi whereas A2AR to the endothelium. ADA inhibitor EHNA and CNT inhibitor formycin B enhanced ADO‐induced DBS.Luminal ADO stimulates DBS via A2BR and CFTR. IAP, ADA and CNT may coordinately regulate luminal ADO concentration to modulate ADO‐P1R signaling in rat duodenum.VA Merit Review, NIH‐NIDDK R01 DK54221
Nuclear Factor kappa B content in internal mammary arteries and saphenous veins in human hypertensive and normotrensive patients
Authors: Watson Ralph Edward , Periera Cristiane Neves , Houghton Dana , Pham Albert Q , Gourineni Nandu , Talbott John D , Fink Gregory D 
Published: June 2021

Many cellular genes involved in immunity and inflammation are regulated at the level of transcription by nuclear factor kappa B (NFkB). Products of these genes include TNF‐alpha and interleukin‐6 (IL‐6). Increased plasma levels of these inflammatory cytokines (IL‐6, TNF‐alpha, etc.) are seen in hypertension (HTN), suggesting that vascular inflammation is part of the pathophysiology of HTN. To our knowledge no one has previously measured NFkB in blood vessels of hypertensive patients. Study objective: Measure NFkB tissue levels in internal mammary artery (IMA) and saphenous vein (SV) tissue in hypertensive and normotensive patients undergoing coronary artery bypass graft (CABG) surgery.MethodsA TransAM NFkB p50 colorimetric ELISA kit was used to measure NFkB content in the vessels in 79 patients undergoing CABG surgery. The patients were interviewed and their hospital charts were abstracted to determine whether the patients had HTN and/or type 2 diabetes.ResultsWe found that there was no significant difference in NFkB p50 activity levels in human IMA or SV between hypertensive and normotensive patients undergoing CABG surgery. We also found that the presence of type 2 diabetes did not affect these levels.ConclusionThese data suggest that vascular inflammation in HTN does not require increased vascular production of NFkB. Grant Support: NIH HL73251.