bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acute regulation of angiotensin II pressor response by heme oxygenase
Authors: Jackson Keith E , Jackson Debra W 
Published: June 2021

Angiotensin II (AngII) induction is a well established model of hypertension with associated enhanced oxidative stress and increase in heme oxygenase activity. Vascular and renal tissues express heme oxygenase, which metabolizes heme to form biliverdin, free iron, and carbon monoxide (CO). CO has been demonstrated to relax vascular smooth muscle and to inhibit nitric oxide synthase. The current study examines the potential of the heme‐heme oxygenase carbon monoxide system to regulate acute AngII mediated increases in blood pressure. In vivo studies were conducted on Inactin anesthetized male Sprague Dawley rats (250–300g) on normal and high Zinc (1mM) diets. A dose response to AngII (5, 10, 20, 25ng/Kg, IV) was conducted to maintain a sustained elevation in blood pressure for an hour and half experimental period. Hemodynamic function was examined before and after acute administration of an inhibitor of CO production, zinc protoporphyrin‐IX (ZnPP; 30μmol/Kg, IV), a precursor for CO production, delta‐aminolevulinic acid (DALA; 40μmol/Kg, IV) or vehicle during AngII co‐infusion. A dose of 5ng/Kg AngII was observed to produce a 30mmHg sustained increase in blood pressure. In AngII hypertensive animals, ZnPP co‐infusion significantly attenuated the AngII increase in blood pressure. DALA or vehicle co‐infusion with AngII had no significant effects on the AngII mediated increase in blood pressure. In animals fed a high Zinc diet for 2 weeks, AngII infusion did not significantly increase blood pressure. This study demonstrates that an inhibitor of CO production can significantly attenuate the AngII mediated increase in blood pressure, while a precursor of CO production had no significant effects.Support: NIH F32 HL76001
EFFECTS OF VITAMIN C CHRONIC TREATMENT ON BLOOD PRESSURE, SYMPATHETIC ACTIVITY AND GENE EXPRESSION IN THE RVLM IN RENOVASCULAR HYPERTENSION
Authors: Barbosa Oliveira‐Sales Elizabeth , Emy Nishi Erika , Aparecida Boim Mirian , Sterman Dolnikoff Miriam , Toledo Bergamaschi Cássia , Ribeiro Campos Ruy 
Published: June 2021

Recently we showed that acute Vitamin C (Vit C) administration (intravenous or directly into the RVLM) caused a significant decrease in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in 2K‐1C, but not in control rats. Moreover, we found that mRNA expression of NAD(P)H oxidase subunits (p47phox and gp91phox) was greater in 2K‐1C compared to the control group in the RVLM and CuZnSOD expression was similar in both groups. However, the chronic effects of Vitamin C (Vit C) in these parameters are unknown. Therefore, here we treated rats with Vit C (150 mg/kg/day) by gavage for 7 days and MAP, RSNA and mRNA expression of NAD(P)H oxidase subunits (p47phox and gp91phox) and CuZnSOD in the RVLM in the 2K‐1C rats was analyzed. The mRNA expression was analyzed by real‐time PCR. The Vit C resulted in a higher fall in MAP in 2K‐1C than in control group (2K‐1C, 22 ± 7%/C, 11 ± 3%) followed of a significant increase in RSNA (41± 2%) only in control group. The NAD(P)H oxidase subunits expression reduced significantly in both groups treated with Vit C in RVLM. In contrast, CuZnSOD expression was unchanged in all groups. The results support the idea that an increase in oxidative stress within the RVLM probably plays a major role in maintaining hypertension and sympathetic drive in 2K‐1C.Supported by FAPESP.
Muscle interstitial norepinephrine and nucleotides during exercise and arterial ATP infusion
Authors: Mortensen Stefan P , González‐Alonso José , Saltin Bengt , Hellsten Ylva 
Published: June 2021

Plasma ATP has been suggested to play a role in the skeletal muscle hyperaemia during muscle contractions, while interstitial ATP may contribute to the increase sympathetic nerve activity, by stimulating muscle afferents. We measured leg hemodynamics and muscle interstitial NE, ATP, ADP, AMP and adenosine during intra‐arterial ATP infusion (0.42±0.04 and 2.26±0.52 μmol min−1;mean±SEM) and one‐legged knee extensor exercise (18±1 and 37±1W) in 7 healthy, male subjects (24±2 years, 76±3 kg). ATP infusion increased leg blood flow (LBF) from 0.4±0.0 l min−1at baseline to 2.8±0.3 (0.42 μmol ATP min−1) and 4.5±0.4 (2.26 μmol ATP min−1) l min−1, while LBF during exercise increased from 0.4±0.1 at rest to 3.6±0.3 (18W) and 4.9±0.5 (37W) l min−1. Interstitial [NE] remained unchanged during the low ATP infusion (0.5±0.2 and 0.7±0.1 μM at baseline and ATP infusion, respectively), but increased to 2.0±0.5μM during the high ATP infusion rate, while [ATP], [ADP], [AMP] and [ADO] remained unchanged during both ATP infusions. Exercise increased interstitial [NE], [ATP], [ADP], [AMP] and [ADO] from 0.5±0.0, 2.0±0.7, 0.06±0.01, 0.06±0.01, 0.2±0.0 and 0.1±0.0 μM, respectively, to 2.9±0.7, 5.61±1.25, 4.80±1.30, 4.1±1.7 and 0.8±0.0 μM, respectively (P<0.05). These results indicate that ATP in plasma exerts its vasodilatory effects directly on the endothelium as arterially infused ATP and its breakdown products do not appear to reach the interstitium. Furthermore, the relationship between interstitial NE and ATP suggests that ATP may play a role in the increased sympathetic nerve activity observed during exercise.Supported by Lundbeck Foundation
Local and distant manifestations of the venoarteriolar reflex
Authors: Kurtev Angel Dimitrov 
Published: June 2021

The venoarteriolar reflex (VAR) is considered a good example of local vasomotor control depending on both myogenic and neural mechanisms. The presence of a neural component suggests generalized effects in‐so‐far as the sensory input may reach systemic vasomotor regulatory centers. The objective of the present study was to find out whether such distant effects are really present. In order to do this we compared the changes in the blood flow of the contralateral arm while inducing the VAR in the ipsilateral one. The VAR was elicited by a local orthostatic stress – lowering of the ipsilateral arm 40 cm below heart level. During the procedure the subject was in supine position with the other arm at heart level. Index finger photoplethysmography from both arms was simultaneously recorded before, during, and after the orthostatic stimulation using PPG100C transducer coupled to a TSD200 amplifier (Biopac Systems Inc.). Precordial single channel ECG was also recorded. The VAR was evaluated by the changes in the amplitude of the photoplethysmography.The results showed the existence of contralateral VAR although less pronounced and more transient than the ipsilateral one. It is concluded that the local orthostatic stress does evoke more widespread changes affecting distant vascular beds.The present study was supported by the Research Committee of Saba University School of Medicine.
cGMP regulates mechanosensitive TRPV4 channels in lung endothelial cells
Authors: Yin Jun , Wu Songwei , Neye Nils , Kuppe Hermann , Kuebler Wolfgang M 
Published: June 2021

Previously, we and others have demonstrated that endothelial Ca2+ influx via activated TRPV4 channels promotes hydrostatic edema formation. Here, we used real‐time microscopy and patch clamp analyses to study the regulation of this mechanosensitive channel by NO/cGMP pathway. In vivo, we tested the ability of sildenafil which prevents the degradation of cGMP by inhibition of phosphodiesterase 5 to attenuate hydrostatic edema in a rat model of left anterior descending coronary artery (LAD) occlusion.In isolated perfused rat lungs, elevation of left atrial pressure from 5 to 15 cmH2O induced an increase in endothelial Ca2+ concentration ([Ca2+]i) from 105±6 to 173±10 nM. This [Ca2+]i response was blocked by TRPV4 inhibitor ruthenium red (RuR; 1 μM), NO donor GSNO (250μM), or cGMP analog 8Br‐cGMP (100 μM) (n=5 each, p<0.05). Activation of TRPV4 by 4αPDD (10 μM) induced an [Ca2+]i increase from 103±4 to 172±20 nM which was again blocked by RuR and 8Br‐cGMP (p<0.05). In pulmonary microvascular endothelial cells, 4αPDD activated an inward current that reversed near +20 mV and was blocked by 8Br‐cGMP. In vivo, sildenafil (1 mg/kg bw) reduced lung wet/dry weight ratio and improved arterial pO2 after LAD occlusion.Our data demonstrate that cGMP attenuates Ca2+ influx via TRPV4 in lung microvascular endothelial cells. This regulatory pathway may present a new therapeutic target for the treatment of hydrostatic lung edema.
Transport of mutagenic vital dye ethidium bromide by the human organic cation transporters hOCT2 and hOCT3
Authors: Lee Wing‐Kee , Ciarimboli Giuliano , Koepsell Hermann , Thevenod Frank 
Published: June 2021

Ethidium bromide (EtBr) and propidium iodide (PI) are widely used in molecular biology as DNA and also as necrosis‐markers. EtBr is not only mutagenic, it may also be carcinogenic, teratogenic or very toxic when inhaled or ingested and therefore poses a major safety problem. Since EtBr strongly stained nuclei in HEK293 cells stably overexpressing human organic cation transporter 2 (hOCT2) with no morphological signs of cell damage or death, vital dye accumulation by HEK293 cells overexpressing known hOCT isoforms was determined by fluorescence microscopy and quantified using a fluorescence microplate reader. All values are mean±SEM. Significant time and concentration‐dependent accumulation of EtBr by hOCT2 (Km=3.4±1.3 μM, n=4) and hOCT3 (Km=2.5±0.4 μM, n=6), but not by hOCT1 cells or HEK293 cells, was observed at 37°C. Conversely, PI was not taken up by any hOCT isoform. The organic cations cimetidine and quinine but not choline competed accumulation of 2.5 μM (IC50: 5.7 mM and 61 μM, respectively) and 12.5 μM (IC50: 10.6 mM and 152 μM, respectively) EtBr in hOCT2 and hOCT3 (IC50 for 12.5 μM EtBr: 1.4 mM and 59 μM, respectively) cells after 5 min. The data indicate that EtBr is transported by hOCT2 and hOCT3. Moreover, acute EtBr intoxication could be prevented by applying high concentrations of less harmful hOCT2 and hOCT3 substrates, such as quinine or cimetidine.Funded by DFG TH 345/8‐1 and TH 345/10‐1
BMAL1 and CLOCK proteins directly bind to the core enhancer of the Myod1 promoter
Authors: zhang xiping , McCarthy John J , Esser Karyn A 
Published: June 2021

The molecular clock regulating circadian rhythms is a network of transcriptional‐translational feedback loops that drive rhythmic expression of genes over a 24‐h period. BMAL1 and CLOCK are two of the main transcription factors that regulate the molecular clock mechanism. Myod1 (myogenic differentiation 1) was identified as having a circadian pattern of expression in adult skeletal muscle. The primary objective of this study was to determine whether CLOCK and BMAL1 bind the Myod1 promoter in a temporal manner. Mice were entrained for 2 weeks in 12 hour light /12 hour dark and then hindlimb muscles were collected every 4 hours for 24 hours. The chromatin immuno‐precipitation (ChIP) assay with nuclear extracts from mouse muscle was performed. We tested binding of BMAL1, CLOCK, and RNA Polymerase to the core enhancer (CE) and distal regulatory region (DRR) of the Myod1 promoter. Results from these studies determined that BMAL1 and CLOCK did bind to the Myod1 promoter but only to the upstream core enhancer CE and not the DRR. Binding of BMAL1 and CLOCK at the CE was also found to oscillate over the course of the circadian cycle. We conclude that Myod1 is a direct clock controlled gene with BMAL1 and CLOCK regulating Myod1 mRNA levels via direct binding to the CE element of the promoter.This research was supported by National Institute of Health grants KAE (AR045617) and JJM (AR053641).
Very low prevalence of acute mountain sickness in teenagers after rapid ascent to 3454 m
Authors: Bloch Jonathan , Duplain Herve , Rimoldi Stefano , Stuber Thomas , Kriemler Susi , Sartori Claudio , Scherrer Urs 
Published: June 2021

Acute mountain sickness (AMS) is a frequent and debilitating complication of high‐altitude exposure. After a rapid ascent to tourist destinations located above 3000 m, as many as 60% of an adult population are affected. Circumstantial evidence suggests that children and teenagers may be even more susceptible to AMS than adults, but direct evidence is lacking. We, therefore, performed serial assessments of AMS (Lake Louise Score, LLS) in 48 teenagers (mean±SD age, 13.7±0.3 yrs; 20 girls and 28 boys) 6, 24, 48 hrs after arrival at the Jungfraujoch high‐altitude research station (3454 m) reached after a 2 hr ascent by train. The major new finding was that 6 hrs after arrival, AMS (LLS≥3) was present in only 22% of the subjects (mean score 4.1±0.4, range 3–7). The incidence of AMS was similar in both genders and steadily declined during the stay (17% at 24 hrs, 8% at 48 hrs). None of the subjects needed pharmacological treatment other than paracetamol. In conclusion, in teenagers the incidence of AMS after rapid arrival at an altitude where major high‐altitude tourist destinations are located world‐wide, is surprisingly low, benign, and resolves rapidly. These findings challenge the notion that teenagers are more susceptible to AMS than adults. They suggest that for the vast majority of teenagers, travel to these altitudes is safe and does not necessitate pharmacological prophylaxis for AMS.Grant support: Swiss National Science Foundation.
Carotid body of transgenic mice with nicotinic ACh receptor a3 subunit deletion
Authors: Wei Edward , Lieu TinaMarie , Balbir Alex , Fujii Koichi , Zadzilka Nicole , Shirahata Machiko 
Published: June 2021

The carotid body (CB) detects the arterial partial pressure of O2 and CO2. Previous studies suggested that nicotinic ACh receptors (nAChRs) play a role in these processes. We investigated if deletion of the nAChR α3 subunit influences gene expression, morphology and function of the CB in 2 week old mice. Real‐time PCR analysis was performed on CB from wild type (WT), heterozygous (HET), and knockout (KO) mice. Cholinergic traits (enzymes for ACh metabolism and receptors) were well preserved in all mice, except for the α3 subunit in KO mice. Dopaminergic traits and BK channels were down regulated in KO mice. Morphometry studies were performed in plastic embedded and serial‐sectioned CBs. The volumes and cell morphology between WT and HET CBs were similar. CB function was assessed by the ventilatory response to short exposures of 100% O2 and 15% O2 using whole body plethysmography. Both WT and HET have similar ventilatory responses to hyperoxia and hypoxia, hypoventilating in response to hyperoxia and hyperventilating in response to hypoxia. The results suggest that the α3 subunit is linked to the expression of BK channels and dopaminergic traits in the CB. Similarities between the phenotypes of WT and HET mice may be due to compensation occurring in the HET.Supported by HL72293. Transgenic mice were originally provided by Dr. De Biasi, Baylor College of Medicine.
Microcirculatory effects of red blood cells with different hemoglobin oxygen affinity in hemorrhagic shock
Authors: Villela Nivaldo R. , Cabrales Pedro , Tsai Amy G. , Intaglietta Marcos 
Published: June 2021

Autoregulation can be considered to be a balance between blood flow and O2 extraction. Local regulatory mechanisms prevent excessive local O2 supply to tissue upstream arteriolar vasoconstriction. Effects of resuscitation with red blood cells (RBCs) with low and high P50 (partial pressure of O2 at 50% Hb saturation) were studied with the hamster window chamber in a model of 1 h shock. Introduction of inositol hexaphosphate (IHP) and 5‐hydroxymethyl‐2‐furfural (5HMF) into the RBCs by electroporation decreased and increased the P50 to 10 and 50 mmHg respectively (normal p50 = 32 mmHg). The animals were resuscitated with 25% of blood volume infusion using either the low and high P50 RBCs. Systemic parameters, microvascular hemodynamics, and functional capillary density (FCD, the number of capillaries perfused per unit area), were measured up to 90 min after resuscitation. RBCs with high P50 (reduced Hb‐O2 affinity) reduced arteriolar diameter and flow, and increased the oxygen extraction. RBCs with low P50 (increased Hb‐O2 affinity) had higher levels of systemic O2 delivery and tissue pO2. In summary, resuscitation with RBCs with increased Hb‐O2 affinity maintained adequate microhemodynamic conditions and tissue PO2 while RBCs with reduced Hb‐O2 affinity produced arteriolar vasoconstriction followed by higher O2 extraction and lower tissue PO2.Supported in part by Bolsista CNPq, HL076182 and HL076182.
The elevation of serum tumor necrosis factor (TNF)‐α and hypothalamic prostaglandin (PG) D2 levels in lipopolysaccharide (LPS)‐induced hypothermia in rats: Possible role of cyclooxygenase (COX)‐1
Authors: Akarsu Eyup S. , Usanmaz Suzan E. , Mamuk Soner 
Published: June 2021

LPS‐induced hypothermia is an adaptive thermoregulatory strategy against immunological challenge in rats. It appears that a selective proinflammatory cytokine (TNF‐α) elevation occurs in the peripheral circulation at the initial phase. Then, an increased PG synthesis may take place in brain, since COX inhibitors abolish the hypothermia. We measured hypothalamic PGD2 and PGE2 levels at this phase. The effects of COX‐1 selective inhibitors (valeryl salicylate [VS] or SC‐560) were also evaluated. LPS (E. coli O111:B4, 250 μg/kg, ip) produced monophasic hypothermia in biotelemetered adult male Wistar rats. The serum TNF‐α elevation was temporally related with the response. The LPS‐injected rats were sacrificed by microwave irradiation. The 4‐Bromomethyl‐7‐methoxycoumarine derivatives of PGD2 and PGE2 were measured by HPLC in hypothalamic homogenates. The PGD2 increased from 58±5 pg/mg (basal) to 274±18 pg/mg wet tissue weight. The PGE2 levels did not increase. SC‐560 (1 mg/kg, sc) abolished the hypothermia and TNF‐α elevation. But, VS (20 mg/kg, sc) inhibited hypothermia and hypothalamic PGD2 increase, without any effect on serum TNF‐α levels. Data suggest that peripheral induction of TNF‐α may also trigger the PGD2 synthesis in hypothalamus, possibly through COX‐1 dependent mechanisms in LPS‐induced hypothermia in rats.Supported by TUBITAK (SBAG‐AYD‐381) and Ankara University ()
Polymorphonuclear leukocyte (PMN) migration across vascular endothelial cells (EC) in the absence or presence of IL‐1β differentially regulate expression of EC adhesion molecules ICAM‐1 and E‐selectin
Authors: Stephen Jancy , Katada Kazuhiro , Cukiernik Mark , Bihari Aurelia , Potter Richard F , Cepinskas Gediminas 
Published: June 2021

Our findings indicate that PMN migration across activated EC results in down‐regulation of EC nuclear transcription factor, NFκB. However, the subsequent functional consequences are largely unknown.In this study we assessed the effects of PMN transendothelial migration on NFκB‐dependent expression of EC adhesion molecules, ICAM‐1 and E‐selectin during inflammation.To this end human endothelial cells (HUVEC) were grown in Traswell inserts and stimulated with IL‐1β (1ng/ml; 4 hrs). Subsequently, PMN were added and allowed to migrate across HUVEC in response to fMLP (10−8M) chemotactic gradient in the absence (i.e. across washed HUVEC) or presence of IL‐1β. ICAM‐1 and E‐selectin gene expression in EC was assessed by RT‐PCR after 4 or 24 hrs following PMN migration.The obtained results indicate that migration of PMN across IL‐1β treated and subsequently washed HUVEC results in a marked down‐regulation of IL‐1 β‐induced ICAM‐1, and to a lesser degree, E‐selectin gene expression as assessed 4 and 24 hrs following PMN migration. On the contrary, migration of PMN across activated HUVEC in the presence of IL‐1β results in a further increase in both, ICAM‐1 and E‐selectin expression.Taken together these findings indicate that migrating PMN differentially modulate expression of EC adhesion molecules during inflammation and can offer EC with both, anti‐ and pro‐inflammatory stimuli (HSFO‐NA5580/NA6171)
Mouse models to study the role of CD34 in allergy and inflammatory diseases
Authors: Blanchet Marie‐Renee , Maltby Steven , Bennett Jami , McNagny Kelly 
Published: June 2021

The CD34 antigen is widely used as a stem cell marker. However, the exact role of CD34 expression is still misunderstood. Our lab is currently using mouse models of allergy and inflammation induced in CD34‐null or chimeric mice in order to elucidate the role of CD34 expression in inflammation.Asthma, hypersentitivity pneumonitis (HP), experimental animal encephalomyetis (EAE) or arthritis was induced in CD34‐null and wild type mice. These pathologies are characterized by activation of various CD34‐expressing cells. Disease progression and cell recruitment and function were compared between wild type and CD34‐deficient mice.In lung inflammation, CD34‐null mice are protected against development of disease and show various cell trafficking defects. In EAE, mast cells accumulate in the CNS of CD34‐null mice, possibly through an emigration defect. Finally, in arthritis, CD34‐null mice show higher susceptibility to disease due to lack of CD34 on vascular endothelia.These results suggest a role for CD34 in hematopoietic cell trafficking, either through CD34 expression on inflammatory cells or vascular endothelia. Also, CD34 expression on vascular endothelia is involved in progression of arthritis. The use of these mouse models in combination with CD34‐null mice has allowed us to better understand the role of CD34 expression in development of inflammation and allergy.
The Ddc1 checkpoint clamp subunit activates Mec1 kinase during the DNA damage checkpoint
Authors: Burgers Peter M , Navadgi Vasundhara M , Majka Jerzy 
Published: June 2021

The DNA damage checkpoint pathway operates to prevent cell cycle progression in response to various genotoxic agents. In Saccharomyces cerevisiae, Mec1‐Ddc2 (human ATR‐ATRIP) is the kinase that initiates most checkpoint pathways. The checkpoint clamp is a heterotrimeric ring, Rad17‐Mec3‐Ddc1 (human 9‐1‐1), and shows structural similarity to the replication clamp PCNA. It is recruited to gapped DNA by the Rad24‐RFC clamp loader and is required for activation of the effector kinase Rad53 (human Chk1 or Chk2) in response to DNA damage.In vitro, the checkpoint clamp is loaded in an ATP‐dependent step onto 5’‐junctions of partial duplex DNA by the Rad24‐RFC clamp loader. The loaded clamp serves to activate Mec1 kinase activity. Activated Mec1 phosphorylates the Ddc1 and Mec3 subunits of the clamp, the Rad24 subunit of the loader, the Rpa1 and Rpa2 subunits of RPA, and the downstream kinase Rad53. We have used this activation system to probe the nature and functionality of interactions between Ddc1 and Mec1.
Visualization of Viruses and Embryos
Authors: Lansford Rusty 
Published: June 2021

Our research aims to dynamically visualize and characterize embryonic development at sub‐cellular resolution. Instead of labeling and following small numbers of cells at a time, we am have developed the means to optically record all or nearly all the cells within a fluorescent protein (FP)‐expressing transgenic quail embryo simultaneously. Cell and tissue movements in the developing embryos are then recorded using multispectral, time‐lapse fluorescent microscopy in 3D.We are tracking the motion of single virus particles and of single viral genomes in living cells using real‐time fluorescence imaging methods. We aim to produce “molecular movies” that will provide mechanistic insight into the biological processes involved in viral mediated gene therapy.