bluuebunny/crossref_metadata_2025_split huggingface dataset:
Renal Medullary Oxygenation Decreases in a Dose‐Dependent Manner with Graded Lower Body Negative Pressure in Healthy Young Adults
Authors: Kim Danielle Jin‐Kwang , Drew Rachel C. , Sica Christopher T. , Yang Qing , Miller Amanda , Cui Jian , Sinoway Lawrence I. 
Published: June 2021

BackgroundIncrease in sympathetic nerve activity (SNA) evokes a renal vasoconstrictor response that is powerfully opposed by autoregulatory influences. In the renal medulla, increases in SNA serve to increase Na+/K+‐ATPase activity (an oxygen dependent process) in the distal tubule, a process contributing to salt and water retention. In this report, we engaged SNA with lower body negative pressure (LBNP) as we employed magnetic resonance imaging to examine an index of renal medullary oxygenation, T2*. At a separate time we applied LBNP as we measured changes in renal blood flow velocity. This is an index that largely reflects changes in renal cortical blood flow.MethodsThirteen healthy (mean age 28 ± 1 yr) men (n = 7) and women (n = 6) participated in one or both of the experimental visits. Graded negative pressure (−10, −20, and −30 mmHg) was applied during 2 visits; visit 1 was for Doppler and visit 2 for MRI. Blood pressure (BP) and heart rate (HR) were also measured at baseline and at each stage of LBNP and recovery. RBV was obtained in all 13 subjects while T2* was obtained in 8 of 13 subjects.ResultsLBNP −30 mmHg led to a lower T2* (−0.65 ± 0.14 ms; P < 0.001). RBV decreased and renal vascular resistance (RVR) increased at −30 mmHg (ΔRBV −7.44 ± 3.87 cm/s, P = 0.041; ΔRVR arbitrary units 0.28 ± 0.11, P = 0.028). During recovery, T2* remained below baseline for the first and the second minutes of the recovery.ConclusionsThese data suggest that −30 mmHg LBNP leads to renal vasoconstriction and medullary deoxygenation. We suspect that changes in T2* are due to a sympathetically mediated, oxygen requiring, accentuation of Na/K ATP activity in the distal tubule. We postulate that this leads to salt and water retention as the SNS is engaged.Support or Funding InformationCommonwealth Universal Research Enhancement Program (CURE); P01 HL134609 (Sinoway)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Responses to short‐term acid loading in proximal‐tubule‐select insulin/insulin‐like growth factor receptor dual knockout mice
Authors: Ecelbarger Carolyn M. , Li Lijun , Tiwari Swasti , Fluitt Maurice B. 
Published: June 2021

Acidosis has been associated with increased renal gluconeogenesis, which in the absence of liver compensation, can lead to hyperglycemia. Acidosis leads to glutamine uptake in the proximal tubule (PT) to liberate bicarbonate and neutralize acids. The remaining carbon skeleton can be used for glucose production at this site. Whether insulin or the related hormone, insulin‐like‐growth‐factor, type 1 (IGF1), modulate these responses to acidosis is unclear. To address this, we bred mice with dual knockout (KO) of the insulin (Insr) and the Igf1r receptors from PT by Cre‐lox recombination using a γ‐glutamyl transferase promoter. KO mice had on average 40% lower expression of both Igf1r and Insr in cortex homogenates. To address the effects of acidosis, male (M) and female (F) wild‐type (WT, Cre negative) and KO (Cre positive) mice were provided ad libitum access to normal drinking water or a water‐based solution containing 1.5% NH4Cl for 7 days (n = 6/treatment/genotype/sex). Fasting (18‐hr) blood glucose was determined in a subset of mice after one week of control then acid treatment. MKO mice showed the greatest mean rise in fasting blood glucose with acid (mg/dl, delta acid‐control): −1.67 (MWT); +15.75 (MKO); −6.40 (FWT); +4.08 (FKO). Urine (24 hr) was collected in metabolic cages on days 5–6. Acid water led to a 30–64% reduction in urine volume in all groups except MWT (ml, delta acid‐control): +0.49 (MWT); −0.54 (MKO); −0.90 (FWT); −1.50 (FKO). Blood chemistry revealed greater sensitivity to acid loading in the male KO. Mean deltas (acid‐control) for blood bicarbonate, base excess, and anion gap, respectively were (mM): −5.73, −7.8, +1.24 (MWT); −8.86, −11.30, +4.67 (MKO); −7.35, −10.36, +4.74 (FWT); −1.67, −1.92, −0.6 (FKO). Western blotting for 3 rate‐limiting enzymes in gluconeogenesis conducted on the cortex from male mice revealed a significant rise in glucose‐6‐phosphatase (G6P), phosphoenolpyruvate carboxykinase (PEPCK), and fructose bisphosphatase (FBP1) in the acid drinking WT males (16–34%). In contrast, MKO mice had a significant reduction in G6P (22%) with acid water; however, FBP1 was increased by acid drinking to a greater extent (60%) in the KO, (as compared to WT, significant interaction). Overall our studies reveal a role for PT‐associated Insr and/or Igf1r signaling in regulating PT responses to an acid load and glucose homeostasis.Support or Funding InformationGeorgetown University Medical CenterGeorgetown/Howard CTSA awardThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Activation of farnesoid X receptor stimulates OCT2 function in human renal proximal tubular cells
Authors: Wongwan Teerasak , Chatsudthipong Varanuj , Soodvilai Sunhapas 
Published: June 2021

Farnesoid X receptor (FXR) is a member of the nuclear receptor subfamily which highly expresses in liver, intestine, and kidney. It plays an essential role in maintaining of bile acids, glucose and lipid homeostasis. Previous reports showed cholestatic condition‐induced chenodeoxycholic acid (CDCA) inhibited organic cation transporter 1 (OCT1) in human and rat liver. However, there is still lack the information concerning the effects of FXR on expression and transport function of renal OCT2 which plays a major role in the renal elimination of cationic compounds. In this study, we investigated whether FXR activation regulates OCT2 in human renal proximal tubular cells. Treatment human renal proximal tubular cells (RPTEC/TERT1 cell) with FXR agonists, 10–100 μM CDCA and 1 μM GW4064, for 24 hours significantly increased intracellular accumulation of 3H‐MPP+, a prototypic substrate of OCT2. The stimulatory effect of FXR agonists was attenuated by co‐treatment with FXR antagonist, Z‐guggulsterone (10 μM) indicating the effect of FXR agonist was mediated by FXR‐dependent mechanism. Kinetic study revealed that CDCA increased OCT2 transport activity by increasing the maximal transport rate (Jmax) of 3H‐MPP+ with no significant effect on its affinity. CDCA treatment at both physiological level (20 μM) and cholestatic condition (80 μM) significantly increased mRNA expression of OCT2. In conclusion, FXR activation by both endogenous and synthetic ligands stimulates renal OCT2 transport function in the proximal tubules at least at transcriptional regulation. FXR activation might play a role in the regulation of renal OCT2 in both a physiological and pathological conditions.Support or Funding InformationThis study was supported by grant from the Royal Golden Jubilee (RGJ; grant no. PHD/0238/2553).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Calibration of intracellular ion probes
Authors: Rana Priyanka S. , Lu Yong , Yurinskaya Valentina E. , Vereninov Alexey A. , Model Michael A. 
Published: June 2021

The development of ion‐sensitive fluorescent probes enables the measurement of intracellular concentrations of ions (such as H+, K+, Na+, Ca2+, etc.) in a non‐invasive manner. One major complication with their use arises from their unpredictable behavior inside the cell, which makes it necessary to calibrate them in situ. Calibration implies creating known intracellular ion concentrations Ci (for example, making them equal to extracellular concentrations Ce) and relating them to the measured fluorescent signal. The question is how to ensure Ci = Ce?Despite the long history of use of intracellular ion probes, the answer to this question is hard to find in the literature. In fact, many of the published calibration protocols clearly fail to achieve the desired goal. We therefore undertook a theoretical and experimental study of this question using K+ as an example. The general recipe for ion equilibration requires two conditions: (1) cell membrane potential should be destroyed; (2) membrane permeability for both K+ and Na+ should be significantly increased. Our results indicate that a combination of gramicidin, valinomycin, nigericin and ouabain is most suitable for achieving equalization of K+ across the membrane. Calibration curves obtained with suboptimal choice of ionophores leads to erroneous potassium measurements.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
ANK3 Knockout Reduces ENaC Activity and Slows Adaptation to a Na+ Free Diet
Authors: Berman Jonathan Max , Mironova Elena , Stockand James 
Published: June 2021

The Epithelial Na+ Channel, ENaC, is the final arbiter of sodium excretion in the kidneys. As such, discretionary control of ENaC by hormones is critical to the fine‐tuning of electrolyte and water excretion and consequently, blood pressure. We recently showed that phosphorylation of ENaC by CK2 in a putative ANK3 binding domain regulates ENaC activity. Therefore we tested the necessity and sufficiency of ANK3 for normal ENaC function. We produced tissue specific ANK3 knockout mice in the aldosterone sensitive distal nephron. Knockout was verified by immunohistochemistry. Split open tubule recordings from these mice showed significantly decreased baseline ENaC activity. The mice displayed a longer adaptation period to a sodium free diet, and a significantly different response to TBB, a casein‐kinase II inhibitor, compared to control. Together these results suggest that ANK3 modulates ENaC activity by interacting with CK2 phosphorylation sites in Beta and Gamma ENaC. In future work we will examine the mechanism by which this interaction modifies ENaC activity.Support or Funding InformationThis research was supported by American Heart Association grants 15GRNT22930030 & 17GRNT3292002 (to JDS), and 17POST33660468 (to JMB), and National Institutes of Health grants T32HL00744536A1 (to JDS and JMB), K12GM111726 (to JMB), and F32DK104572 (to EM).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Regulation of ENaC by Casein Kinase II
Authors: Berman Jonathan Max , Mironova Elena , Stockand James 
Published: June 2021

The Epithelial Na+ Channel, ENaC, is the final arbiter of sodium excretion in the kidneys. As such, discretionary control of ENaC by hormones is critical to the fine‐tuning of electrolyte and water excretion and consequently, blood pressure. Casein kinase 2 (CK2) phosphorylates ENaC. Phosphorylation by CK2 is necessary for normal ENaC activity. We tested the physiological importance of CK2 regulation of ENaC as the degree to which ENaC activity is dependent on CK2 phosphorylation in the living organism is unknown. This was addressed using patch clamp analysis of ENaC in split‐open collecting ducts in complement with whole animal physiological studies of sodium excretion in mice. We also used ENaC harboring CK2 phosphorylation site mutations to elaborate mechanism. We found that ENaC activity in ex vivo preparations of murine collecting duct had a significant decrease in activity in response to selective antagonism of CK2. In whole animal experiments selective antagonism of CK2 caused a natriuresis similar to benzamil, but not additive to benzamil, suggesting an ENaC dependent mechanism. Regulation of ENaC by CK2 was abolished by mutation of the canonical CK2 phosphorylation sites in beta and gamma ENaC. Together, these results demonstrate that the appropriate regulation of ENaC by CK2 is necessary for the normal physiological role played by this key renal ion channel in the fine‐tuning of sodium excretion.Support or Funding InformationThis research was supported by American Heart Association grants 15GRNT22930030 & 17GRNT3292002 (to JDS), and 17POST33660468 (to JMB), and National Institutes of Health grants T32HL00744536A1 (to JDS and JMB), K12GM111726 (to JMB), and F32DK104572 (to EM).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Serotonergic immunoreactivity in the brainstem and spinal cord of mdx mice
Authors: Wollman Lila Buls , Sunshine Michael D. , Burns David P. , O'Halloran Ken D. , Fuller David D. 
Published: June 2021

The mdx mouse model of Duchenne muscular dystrophy exhibits profound respiratory muscle weakness and muscle fiber remodeling. Initial studies of respiratory control in mdx mice indicate increased respiratory motor output during respiratory challenge, possibly indicating a compensatory neuroplastic response of the respiratory neural control system in the face of muscle pathology (Burns et al., J Physiol, 2017). Serotonin plays a fundamental role in the induction of respiratory neuroplasticity, and in ongoing experiments we are testing the hypothesis that mdx mice have a compensatory increase in serotonergic innervation of the brainstem and spinal cord. The cervical (C4) and thoracic (T4) spinal cord and medulla of three‐month‐old wild type and mdx mice were harvested and incubated with antibodies to recognize serotonin and choline acetyltransferase (ChAT) to identify motoneurons. The intensity of serotonergic immunostaining was quantified in an unbiased manner using a custom Matlab code. In the cervical spinal cord, serotonergic immunostaining was prominent in the ventral horn (lamina 9). The thoracic cord also showed serotonergic immunoreactivity in the aforementioned region, but staining was most prominent in the lateral horn (intermediolateral nucleus). There was no indication of differences in spinal serotonergic staining between control and mdx mice. In contrast, the mdx mice showed a clear trend toward increased serotonin staining in caudal medullary regions important for cardiovascular and respiratory control, including the nucleus ambiguous, hypoglossal motor nucleus, and the dorsal motor nucleus of the vagus. These preliminary findings support the hypothesis that serotonergic neurons undergo neuroplastic changes in mdx mice, and this may have implications for respiratory motor control.Support or Funding InformationT32‐HL134621‐01A1 (LBW), T32‐HD043730 (MDS), SPARC OT2 OD023854 (DDF), 1 R01 NS080180‐01A1 (DDF)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Calcium Oscillations in Human Pulmonary Artery Smooth Muscle Cells: Developing a Hierarchical Clustering Method for Analysis and the Effects of IL‐1b
Authors: Kim Elizabeth H. , Griffis Khris G. , Sheppard Meredith , Alamro Suliman , Tabari Daniel , Garfinkel Alan , Jones Heather D. 
Published: June 2021

RationaleAcute respiratory distress syndrome (ARDS) is characterized by lung inflammation, edema, and severe hypoxemia. In previous work, we showed that IL‐1b is required for the development of severe hypoxemia in a murine model of acute lung injury, independent of measures of inflammation and edema. We hypothesized that IL‐1b is altering the regulation of pulmonary blood flow to cause severe V/Q mismatching in acute lung injury. To explore possible mechanisms for this, we studied the effects of IL‐1b on calcium flux in human pulmonary artery smooth muscle cells (hPASMCs) in response to the vasoconstrictor endothelin‐1 (ET‐1).MethodshPASMCs were grown on glass bottom dishes to confluence and some dishes were treated with IL‐1b (10ng/mL) for 3h. Cells were loaded with 5mM Cal‐520 and stimulated with ET‐1 (10nM) during fluorescent imaging on a Zeiss LSM confocal microscope. All cells from each field were individually selected using Fiji image analysis software. By visual inspection, we noticed that a marked number of cells showed oscillations in calcium flux after ET‐1. To quantify oscillatory from non‐oscillatory responses, we used a mixture of information theoretic and machine learning algorithms and developed a custom classifier tool. We applied this tool to our control and IL‐1b‐treated data (Figure 1) and created a contingency table for the effects of IL‐1b on the induction of oscillatory responses. χ2 confidence intervals and statistical significance were computed by bootstrap simulation with 105 replicates using custom scripts in R(v3.4.1).ResultsIn control dishes (n = 6), there were a total of 444 non‐oscillators cells and 379 oscillator cells. In dishes treated with IL‐1b (n = 2), there were 50 non‐oscillator cells and 211 oscillators total. A bootstrap simulation based χ2 test was performed and a strong relationship was found between IL‐1b treatment and the presence of oscillatory responses, χ2 = 96.7 (71.2, 125.5; 95% C.I.), p < 10−5.Support or Funding InformationNat'l Heart, Lung & Blood Inst.K08HL125806This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Transient Receptor Potential Melastatin 8 (TRPM8) Induced Relaxation of Pulmonary Artery is Mediated Through Inhibition of Store‐Operated Ca2+ Entry in Normoxic and Chronic Hypoxic Rats
Authors: Mu Yun‐Ping , Jiao Hai‐Xia , Lin Da‐Cen , Zheng Si‐Yi , Sham James , Lin Mo‐Jun 
Published: June 2021

Pulmonary hypertension (PH) is characterized by profound vascular remodeling and alterations in Ca2+ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Members of multiple transient receptor potential subfamilies (TRPC, TRPV, and TRPM) have been identified in pulmonary vascular tissue. Our previous studies showed that the expression and functions of the store‐operated TRPC1, receptor‐operated TRPC6, and the mechanosensitive TRPV4 channels are augmented in PASMCs during PH, and their upregulation contribute to PH development. In contrast, TRPM8 is down‐regulated in PASMCs of rats PH models, and activation of TRPM8 with agonists causes relaxation of pulmonary arteries (PAs)(Liu et al., Cell Physiol Biochem 2013, 31:892–904). However, the mechanism of TRPM8‐induced PA relaxation has not been determined. In this study, we examined the possible interactions of TRPM8 activation and store‐operated Ca2+ entry (SOCE) in PAs and PASMCs of normoxic and chronic hypoxic pulmonary hypertensive (CHPH) rats. We found that TRPM8 expression was down‐regulated in PAs and the TRPM8‐mediated cation entry was reduced significantly in the PASMCs of rats after 3 weeks of hypoxia (10% O2) exposure. Activation of TRPM8 with icilin (0.1–100 μM) caused concentration‐dependent relaxation of cyclopiazonic acid (CPA) and ET‐1 pre‐contracted endothelium‐denuded PAs in the presence of nifedipine. The vasorelaxant effect of icilin was abolished in the presence of the SOCE antagonist Gd3+ at submicromolar concentration. Icilin suppressed the CPA‐induced cation entry in PASMCs determined by the Mn2+ quenching technique and by Ca2+ transient measurement. The inhibitory effect of icilin on SOCE‐induced PA relaxation and Ca2+ entry were abolished by the TRPM8 antagonist AMTB, indicating that the effect was mediated specifically by TRPM8 channels. Moreover, TRPM8‐mediated inhibitory effects on CPA‐induced contraction in PAs and SOCE in PASMCs were significantly augmented in CHPH rats, probably related to the enhanced SOCE caused by PH. These results demonstrate for the first time that TRPM8 activation can cause relaxation of PA through inhibition of SOCE. Since SOCE plays many important roles in pulmonary vascular functions and is crucial for the vascular remodeling and the enhanced vasoconstriction in PH, the downregulation of TRPM8 expression and activity in PASMCs during PH may minimized the TRPM8‐dependent inhibition of SOCE, and allow unimpeded SOCE activity for PH development.Support or Funding InformationSupported by grants NSFC31571179, NSFC31371165, NSF of Fujian Province 2015J01313, and Fujian Province Hundred Experts Award.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Impact of Student's Prior Experience on the Design of Virtual Labs for Biomedical Courses
Authors: Silva Ricardo Alfonso Pena , Rivas Jose Oscar Mantilla , Rodriguez Daniel Francisco Santamaria , Montero Silvia Marcela Gomez , Akle Veronica 
Published: June 2021

Laboratory practices facilitate deep learning in biomedical sciences, however, they require experience in laboratory techniques, financial resources and institutional infrastructure. This is why the use of “in silico” or virtual laboratories is a viable alternative to teach fundamental biomedical concepts to students of medicine and science. Our objective is to evaluate the impact of virtual laboratories on medical students.Students of the third and fourth semesters of medicine used simvesel and simheart (Virtual Phisiology) simulators. We evaluated the perceptions and outcomes associated with the simulation of experiments related to concepts of the autonomic nervous system and cardiac mechanics.Students from earlier semesters arrive with less prior knowledge than advanced students. However, both groups improve their mastery of the subject in similar magnitude. Although the instructions and tasks were the same for the groups, the students of third semester seem to have more problems with the manipulation of the simulator and show a slightly less positive experience.After a second experience with the simulator, advanced students do not show changes in their already positive experience with the simulator. Third semester students, however, report a much higher functionality and usability with the simulator and a more favorable impact on their learning.In conclusion, the use of virtual laboratories is a cost‐effective intervention to teach complex concepts of physiology and pharmacology. Students consider that these types of laboratories allow them to achieve deeper learning even though they may need to gain mastery in some elements of the simulators. Teachers should consider the importance of the students' experience when developing biomedical simulation activities.Support or Funding InformationUniversidad de los Andes, Medical School and “Innovations in Education” Initiative of Conecta‐Te.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.