bluuebunny/crossref_metadata_2025 huggingface dataset:
Fiscal Rules in the European Union: Less Is More
Authors: Căpraru Bogdan , Pappas Anastasios , Sprincean Nicu
Published: May 2024

In this article, we examine the non‐linear relationship between the number of fiscal rules in place and compliance with the European Union's (EU) numerical fiscal targets included in the Stability and Growth Pact (SGP). Using a sample composed of 27 EU Member States for a period spanning 2000 to 2021, we document that countries' compliance with fiscal rules is positively associated with the number of numerical fiscal targets. However, this association only holds up to a specific threshold. Once this threshold is achieved, the relationship becomes negative, implying that the multiplication of numerical fiscal rules may undermine compliance, thereby reducing their effectiveness. In addition, we find that general elections and frequent changes in government reduce compliance, whereas economic adjustment programmes contribute positively to countries' compliance with fiscal targets. The findings bear critical policy implications against the backdrop of the current review of the European fiscal framework.
Authorship and Accountability: Kierkegaard and Anonymity in the Press
Authors: Westfall Joseph
Published: May 2024

Søren Kierkegaard was engaged with the press in a variety of ways throughout his authorship. Although studies of Kierkegaard's interactions with the public press of his time have largely focused on his dispute with the satirical newspaper, Corsaren, in this paper I examine his first engagement with the press—a mostly anonymous newspaper dispute with the Danish social activist, Orla Lehmann, about the freedom of the press in Denmark—as a lens through which to understand his thoughts on the press in general, on anonymous authorship in the newspapers and otherwise, and the ethical and religious significance Kierkegaard sees in the methods we employ, including anonymity, when we engage one another in public writings.
Challenging the policy space: The legitimation of alternatives in Chilean pension policy (1980–2019)
Authors: Rozas‐Bugueño Joaquín , Maillet Antoine
Published: May 2024

In October 2019, Chile experienced its most significant cycle of protests since the return to democracy in 1990; one of the primary demands of this cycle was the improvement of pensions. What effect did the October upheaval have on the Chilean pension policy debate? How have ideas about the Chilean pension plan changed from its creation in 1981−2019? What are the main drivers of these changes? In this study, we propose the concept of policy space, which we define as the realm of ideas wherein public policies are debated and whose boundaries are determined by the legitimacy of ideas from relevant actors. We use a process‐tracing approach based on qualitative data triangulation from several techniques including in‐depth interviews, press analysis, and secondary document review. The findings indicate that the shift in the ideas related to pension policy is explained by two drivers—long‐term linkage among actors and short‐term social mobilization against the private pension system, which accelerated rapidly with the October 2019 protests.
Risk Analysis on the Equipment and Material Procurement Process of Engineering, Procurement, and Construction (EPC) Projects
Authors: Berawi Mohammed Ali , Soepardi Aryartha , Sayuti Mustika Sari
Published: May 2024

Equipment and material non-compliance with the project requirements is one of the issues causing delay in large EPC projects as rework actions are inevitable. Detecting and controlling the potential risks at the procurement process of equipment and material can be done to anticipate this issue. This study aims to identify the major risks and recommend the response strategies to the equipment and material non-compliance by adopting a quantitative method through expert validation using Delphi method, questionnaire surveys, and risk analysis, as well as qualitative method through benchmarking study and interview with experts. The result of this study shows that lacking in the inspection of requirement, complete Request for Quotation (RFQ) information, contract term verification, fixed design requirements, attention to Purchase Order (PO) review, supervision to engineering design and drawing, and proper fabrication procedure are major risks that can potentially cause non-compliance. Improvement in communication between stakeholders and supervision to ensure the conformity with specifications are considered as the key elements in mitigating the identified major risks.
Myths and Methodologies: Standardisation in Human Physiology Research—Should We Control the Controllables?
Authors: Merrell Lucy H. , Perkin Oliver J. , Bradshaw Louise , Collier-Bain Harrison D. , Collins Adam J. , Davies Sophie , Eddy Rachel , Hickman James A. , Nicholas Anna P. , Rees Daniel , Spellanzon Bruno , James Lewis J. , McKay Alannah K.A. , Smith Harry A. , Turner James E. , Koumanov Francoise , Maher Jennifer , Thompson Dylan , Gonzalez Javier T. , Betts James A.
Published: May 2024

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants’ habitual diets, yet a self-report and replication method can be flawed by under-reporting. Researchers may also need to consider standardisation of physical activity, whether it be through familiarisation trials, wash-out periods, or guidance on levels of physical activity to be achieved before trials. In terms of pharmacological agents, the ethical implications of standardisation require researchers to carefully consider how medications, caffeine consumption and oral contraceptive prescriptions may affect the study. For research in females, it should be considered whether standardisation between- or within-participants in regards to menstrual cycle phase is most relevant. The timing of measurements relative to various other daily events is relevant to all physiological research and so it can be important to standardise when measurements are made. This review summarises the areas of standardisation which we hope will be considered useful to anyone involved in human physiology research, including when and how one can apply standardisation to various contexts.
High intestinal carriage of
Clostridium perfringens
in healthy individuals and ICU patients in Hangzhou, China
Authors: Yan Zelin , Fu Bo , Zhu Yanyan , Zhang Yanyan , Wu Yuchen , Xiong Panfeng , Zhou Hongwei , Wang Yang , Wang Shaolin , Chen Gongxiang , Zhang Rong , Sun Chengtao
Published: May 2024

Clostridium perfringens
has emerged as a growing public health concern due to its ability to cause various infections and its increasing resistance to antibiotics. To assess its current epidemiology in clinical settings, we conducted a survey involving 426 healthy individuals and 273 ICU inpatients at a provincial hospital in China. Our findings revealed a high prevalence of
C. perfringens
in healthy individuals (45.77%, 95% CI: 41.0%–50.6%) and ICU patients (12.82%, 95% CI: 9.1%–17.4%). The identified 220
C
.
perfringens
isolates displayed substantial resistance to erythromycin (57.9%), clindamycin (50.7%), and tetracycline (32.0%), primarily attributed to the presence of
erm
(Q) (54.4%),
lnu
(P) (13.8%),
tet
B(P) (83.6%), and
tet
A(P) (66.7%). Notably,
C. perfringens
isolates from this particular hospital demonstrated a high degree of sequence type diversity and phylogenic variation, suggesting that the potential risk of infection primarily arises from the bacteria’s gut colonization rather than clonal transmissions within the clinical environment. This study provides an updated analysis of the current epidemiology of
C. perfringens
in healthy individuals and ICU patients in China and emphasizes the need to optimize intervention strategies against its public health threat.

IMPORTANCE

Clostridium perfringens
is a bacterium of growing public health concern due to its ability to cause infections and its increasing resistance to antibiotics. Understanding its epidemiology in clinical settings is essential for intervention strategies. This study surveyed healthy individuals and ICU inpatients in a provincial hospital in China. It found a high prevalence of
C. perfringens
, indicating infection risk. The isolates also showed significant antibiotic resistance. Importantly, the study revealed diverse sequence types and phylogenetic variation, suggesting infection risk from intestinal colonization rather than clonal transmission in hospitals. This analysis emphasizes the need to optimize intervention strategies against this public health threat.
Multimodal inhibitory effect of matcha on
Porphyromonas gingivalis
Authors: Nakao Ryoma , Takatsuka Ayami , Mandokoro Kengo , Narisawa Naoki , Ikeda Tsuyoshi , Takai Hideki , Ogata Yorimasa
Published: May 2024

Porphyromonas gingivalis
has been associated with progression of periodontitis, characterized by inflammation and destruction of periodontal tissues. Here, we report that matcha, a product of
Camellia sinensis
, hampers the adherence and survival of
P. gingivalis
through multiple tactics. Matcha extract (ME) inhibited the growth not only of
P. gingivalis
but also of
Prevotella nigrescen
s and
Fusobacterium nucleatum
, while it did not inhibit growth of nine species of oral streptococci and
Aggregatibacter actinomycetemcomitans
. ME-mediated
P. gingivalis
growth inhibition was characterized by both morphological and physiological changes at the bacterial envelope, which were accompanied by nano-particle formation and decreased membrane fluidity/permeability without loss of membrane integrity. ME also triggered autoaggregation of
P. gingivalis
in a major fimbriae (FimA)-dependent manner. In addition, adherence of
P. gingivalis
was dramatically inhibited by ME, irrespective of fimbriae. Furthermore, a structure-activity relationship study tested a series of catechins isolated from ME and identified the pyrogallol-type B-ring of catechins as essential for
P. gingivalis
growth inhibition. In a clinical study to assess the microbiological and therapeutic effects of matcha mouthwash in patients with periodontitis, the
P. gingivalis
number in saliva was significantly reduced by matcha mouthwash compared to the pre-intervention level. A tendency toward improvement in probing pocket depth was observed in the matcha group, although the difference was not statistically significant. Taken together, we present a proof of concept, based on the multimodal inhibitory effect of matcha against
P. gingivalis
, and that matcha may have clinical applicability for prevention and treatment of periodontitis.

IMPORTANCE

Periodontitis, a multifactorial inflammatory disease of the oral cavity, results in alveolar bone destruction, and is a major cause of tooth loss of humans. In addition, emerging evidence has demonstrated associations between periodontitis and a wide range of other chronic inflammation-driven disorders, including diabetes mellitus, preterm birth, cardiovascular disease, aspiration pneumonia, rheumatoid arthritis, cognitive disorder, and cancer. In the present study, we report that matcha, a product of
Camellia sinensis
, hampers
Porphyromonas gingivalis
, a major periodontal pathobiont, in not only a series of
in vitro
experiments but also a pilot intervention clinical trial of patients with periodontitis, in which matcha mouthwash statistically significantly reduced the
P. gingivalis
number in saliva, as compared to the pre-intervention level. Taken together, we suggest that matcha may have clinical applicability for prevention and treatment of periodontitis.
Laryngeal response to high-intensity exercise in healthy athletes
Authors: Carlsen Petter Helø , Muralitharan Praveen , Fenne Hilde , Hammer Ida Jansrud , Engan Mette , Vollsæter Maria , Bovim Lars Peder , Røksund Ola Drange , Halvorsen Thomas , Clemm Hege Havstad
Published: May 2024

Introduction

Exercise-induced laryngeal obstruction (EILO) is a common cause of exertional breathing problems. The current diagnostic approach rests on evaluation of laryngeal obstruction visualised by laryngoscopy performed continuously throughout a maximal exercise test (continuous laryngoscopy exercise (CLE) test) in patients who present with compatible symptoms. Laryngeal responses to high-intensity exercise in endurance athletes are not well described, potentially leading to inaccurate reference values and increasing the risk of misdiagnosing EILO.

Aim

To investigate laryngeal responses to high-intensity exercise in a healthy population of endurance athletes with no self-reported perception of respiratory problems.

Methods

A cross-sectional study was conducted at Haukeland University Hospital, Bergen, Norway, inviting amateur and professional athletes with no self-reported breathing problems who performed endurance training minimum four sessions weekly. Thirty-six eligible athletes completed a questionnaire detailing exercise habits and past and current respiratory symptoms. They performed a standardised CLE test from which cardiopulmonary exercise data and corresponding laryngeal responses were recorded. The CLE tests were evaluated in retrospect by two independent raters according to preset criteria providing a CLE score. The CLE score rates the severity of laryngeal obstruction during moderate and maximum exercise on the glottic and supraglottic regions on a scale ranging from 0 (no obstruction) to 3 (maximum obstruction).

Results

Twenty-nine (81%) athletes (15 females) aged 15–35 years completed a CLE test. Ten participants (33%) had a supraglottic CLE subscore of 2 or 3. Among these, two also had a glottic CLE subscore of 2 or 3. Notably, none had isolated glottic obstruction.

Conclusion

In healthy well-trained endurance athletes with no prior perception of respiratory symptoms, the laryngeal response to high-intensity exercise was diverse. Supraglottic laryngeal obstruction was observed in one-third of the athletes. The findings underline that a diagnosis of EILO should rest on observed laryngeal obstruction supported by compatible symptoms.
Severe enterovirus infections in patients with immune-mediated inflammatory diseases receiving anti-CD20 monoclonal antibodies
Authors: Martin de Frémont Grégoire , Chabrolles Hélène , Mirand Audrey , L'Honneur Anne Sophie , Mélé Nicolas , Dunogue Bertrand , Boutboul David , Farhat Meryem , Hachulla Eric , Lazrek Mouna , Rieu Virginie , Mathian Alexis , Chaussade Helene , Ruet Aurelie , Burrel Sonia , Coury-Lucas Fabienne , Schuffenecker Isabelle , Lemaignen Adrien , Stefic Karl , le Besnerais Maelle , Carrette Marion , Mouthon Luc , Avettand-Fenoel Veronique , Terrier Benjamin , Hadjadj Jérome
Published: May 2024

Objective

Patients with X linked agammaglobulinemia are susceptible to enterovirus (EV) infections. Similarly, severe EV infections have been described in patients with impaired B-cell response following treatment with anti-CD20 monoclonal antibodies (mAbs), mostly in those treated for haematological malignancies. We aimed to describe severe EV infections in patients receiving anti-CD20 mAbs for immune-mediated inflammatory diseases (IMIDs).

Methods

Patients were included following a screening of data collected through the routine surveillance of EV infections coordinated by the National Reference Center and a review of the literature. Additionally, neutralising antibodies were assessed in a patient with chronic EV-A71 meningoencephalitis.

Results

Nine original and 17 previously published cases were retrieved. Meningoencephalitis (n=21/26, 81%) associated with EV-positive cerebrospinal fluid (n=20/22, 91%) was the most common manifestation. The mortality rate was high (27%). EV was the only causal agents in all reported cases. Patients received multiple anti-CD20 mAbs infusions (median 8 (5–10)), resulting in complete B-cell depletion and moderate hypogammaglobulinemia (median 4.9 g/L (4.3–6.7)), and had limited concomitant immunosuppressive treatments. Finally, in a patient with EV-A71 meningoencephalitis, a lack of B-cell response to EV was shown.

Conclusion

EV infection should be evoked in patients with IMIDs presenting with atypical organ involvement, especially meningoencephalitis. Anti-CD20 mAbs may lead to impaired B-cell response against EV, although an underlying primary immunodeficiency should systematically be discussed.
Third-order relativistic fluid dynamics at finite density in a general hydrodynamic frame
Authors: Diles Saulo M. , Miranda Alex S. , Mamani Luis A. H. , Echemendia Alex M. , Zanchin Vilson T.
Published: May 2024

The motion of water is governed by the Navier–Stokes equations, which are complemented by the continuity equation to ensure local mass conservation. In this work, we construct the relativistic generalization of these equations through a gradient expansion for a fluid with a conserved charge in a curved d-dimensional spacetime. We adopt a general hydrodynamic frame and introduce the irreducible-structure (IS) algorithm, which is based on derivatives of the expansion scalar and the shear and vorticity tensors. By this method, we systematically generate all permissible gradients up to a specified order and derive the most comprehensive constitutive relations for a charged fluid, accurate to third-order in the gradient expansion. These constitutive relations are formulated to apply to ordinary (nonconformal) and conformally invariant charged fluids. Furthermore, we examine the frame dependence of the transport coefficients for a nonconformal charged fluid up to the third order in the gradient expansion. The frame dependence of the scalar, vector, and tensor parts of the constitutive relations is obtained in terms of the (field redefinitions of the) fundamental hydrodynamic variables. Managing the frame dependencies of the constitutive relations is challenging due to their non-linear character. However, in the linear regime, the higher-order transformations become tractable, enabling the identification of a set of frame-invariant coefficients. Subsequently, the equations obtained in the linear regime are solved in momentum space, yielding dispersion relations for shear, sound, and diffusive modes for a non-conformal charged fluid, expressed in terms of a set of frame-invariant transport coefficients.
Semi-quantum blind double signature scheme with semi-trusted arbitrator
Authors: Zhang Ling , Zhang Jia-Hao , Xin Xiang-Jun , Li Chao-Yang
Published: May 2024

In order to solve the security of electronic transactions on limited goods, some quantum blind double signature (QBDS) protocols were proposed. In existing QBDS protocols, all participants must have specific quantum computing capabilities. Realistically, high cost of quantum devices may hinder people from using the QBDS protocol. Therefore, we propose a semi-quantum arbitrator blind double signature (SQABDS) scheme. In this scheme, the sender (signer) and the receiver both are classical participants, which can relatively reduce the dependence on quantum hardware. The introduction of blind signers can protect the privacy of electronic transactions, the introduction of semi-trusted arbitrator can relax the strong assumption about the trustworthiness of the arbitrator, for the arbitrator cannot forge the signature. In addition, the SQABDS scheme can be used to sign classical messages directly without performing any quantum swapping tests or quantum gate operations. Finally, the analysis shows that our scheme is securer and its quantum cost is relatively lower.
The Effect of High Impact Teaching Practices on Student Comprehension
Authors: Safford Susan , Pathak Jawahar
Published: May 2024

Despite a large number of published studies on high-impact teaching practices (HIP), there is little consistency in design or measurable outcomes and few quantitative studies, which leads to a lack of information on how specific HIPs improve learning outcomes. Therefore, the research questions for this study are a) does the same HIP have similar results across sections and, b) does a HIP in one section result in a different learning outcome than in another section that does not have a HIP? The hypothesis for the first question is there is no difference in student comprehension between sections when all sections have the same HIP. The hypothesis for the second question is there will be a difference in student comprehension between sections, with students exhibiting greater comprehension in the section with the HIP. For several years we have been using a variety of HIPs in our classes without measuring their impact. This is a preliminary study designed to measure the impact of HIPs on two different sections of Human Anatomy and Physiology II, taught by the same professor. The design of the study is as follows:

[Formula: see text]

We will analyze our data for two attributes, average and variability of pre-tests and post-tests. For the first attribute, we will study mean distribution. T-test analysis of the mean will be used to measure differences between sections for the pre-test and each post-test. Similarly, T-test analysis of the means will be used within each section to analyze differences between the pre-test and each post-test. For the second attribute, we will use F-test analysis of variance. Tests of normality of grade distribution for three assignments or tests in two sections of a typical biology class were conducted. Our analyses showed that all skewness and kurtosis values were between -2 to 2, and the median and mean were very close. Thus, it is reasonable to assume that the data are from normally distributed populations. Therefore, the approach we have outlined to measure HIP impact is appropriate for our classes. The results from this preliminary study will be used to identify specific HIPs that result in higher learning outcomes and will assist us in refining our pedagogical approach.

Funding was provided by Lincoln University's Offce of Title III; Award #P031E200019-HBCU Title III, Part F Program.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Megalin-mediated siRNA uptake in kidney proximal tubule cells
Authors: Long Kimberly , Rbaibi Youssef , Cunniff Jeremy , Qadir Deena , Lawrence Jonathan , Weisz Ora
Published: May 2024

Small interfering RNA (siRNA) is a clinically validated therapeutic modality, which silences gene expression via RNA interference (RNAi). Systemically delivered siRNA molecules are excreted primarily via the kidneys, where they accumulate in the renal cortex. Proximal epithelial cells within the tubule are thus an attractive target cell for utilizing RNAi, where the primary mode of entry is likely endocytic uptake. Here we report using a well-differentiated, opossum kidney (OK) proximal tubule cell (PTEC) line as a model system to mimic proximal tubule biology and investigate siRNA uptake. Fluorescently tagged siRNA were employed to observed uptake, which was observed in both a time and concentration dependent manner occurring predominantly from the apical surface of OK cells. Live cell imaging revealed significant colocalization of siRNAs with LysoTracker, consistent with endocytic uptake and delivery to lysosomes. We investigated the role of key PTEC solute recovery receptors, megalin and cubilin. siRNA uptake was inhibited by the megalin-binding protein RAP; and was independently reduced in Lrp2 knock-out (KO) cell lines. This work suggests that PTECs employ megalin to facilitate uptake of siRNA via endocytosis. Additionally, we observed colocalization of siRNA molecules and megalin in mouse kidneys from in vivo studies. Elucidating the mechanism(s) for siRNA uptake in the proximal tubule aids in the development of RNAi renal therapeutics and, more broadly, the understanding of class effects associated with siRNA nephrotoxicity. Additional work is focused on intracellular traffcking and megalin mediated siRNA uptake in mice.

Project funded by Judo Bio.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Overexpression of Regulator of G-Protein Signaling 2 in the Paraventricular Nucleus Reduces Blood Pressure in Spontaneously Hypertensive Rats
Authors: Boomer Shane , Liu Xuefei , Zheng Hong
Published: May 2024

The hypothalamic paraventricular nucleus (PVN) is important in mediating sympathetic activity to regulate blood pressure. The regulator of G protein signaling 2 (RGS2) is a negative G protein regulator. RGS2 selectively regulates Gαq signaling, an important cause of hypertension and cardiac hypertrophy. However, little-to-no studies are being done related to G-protein-RGS2 signaling on the central mechanisms of blood pressure control and sympathetic activation. In this study, we use spontaneously hypertensive rats (SHR) to aim for the pressor effects of central viral transfection over-expressing RGS2 in the PVN compared to a Wistar-Kyoto (WKY) control. These rats were outfitted with telemetry and measurements of blood pressure and heart rate over the next 14 days, with or without RGS2 adenovirus (AV) injection into the PVN. Metabolic experiments were conducted at the 7-day mark to examine kidney function, sodium excretion, urine output, and water and food intake. We saw significant ( p<0.05) decreases in blood pressure for the SHR with AV-RGS2 throughout our telemetry experiment. In our metabolic experiments, sodium excretion significantly ( p<0.05) increased in the SHR group with AV-RGS2 compared to the SHR with AV-GFP. Water intake, food intake, and urine output remained unchanged. Following this experiment, we gave capsaicin injections into the renal pelvis at 5, 10, and 20 μM to measure blood pressure and heart rate responses. Also, blood pressure responses to renal pelvis capsaicin injection appear to be attenuated in SHR and WKY rats with AV-RGS2 injection but was not significant ( p>0.05). In addition, we conducted real-time qPCR on collected PVN tissue to evaluate gene expression changes over time. We saw expression peak at 3-days in G⍺q, G⍺s, G⍺i, and RGS2, and progressively decrease as time progressed. This study provides a value insight of central mechanisms related to G-protein-RGS2 signaling on blood pressure regulation.

This study was funded by NIH R01-DK-129311 and USD G-RISE, NIH T32GM-136503.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Caveolin-1 frame-shift mutation induces multifunctional alterations in human fibroblasts that are exosome-mediated
Authors: Zuniga Hertz Juan Pablo , Chiteti Ramamurthi , Patel Hemal
Published: May 2024

Caveolins, Cav1-3, are oligomeric proteins critical for the formation of membrane caveolae that regulate cell physiology. A de novo frameshift mutation (Cav1F160X) in Cav1 (Cav1M) was described in a patient with a progeria-like phenotype, lipodystrophy, and pulmonary hypertension. We hypothesize that Cav1M presents as a dominant negative protein that perturbs cellular physiology, particularly nuclear morphology, mitochondrial function, plasma membrane structure, and exocytic behavior. Transmission electron microscopy (TEM) of patient-derived dermal fibroblasts (Cav1M) showed abnormal nuclear shape, increased rough endoplasmic reticulum, and an increased number of autophagosomes. Cav1M cells present an abnormal mitochondrial size and shape, accompanied by a reduced mitochondrial capacity for energy production detected by Seahorse real-time oximetry analysis. In addition, we observed in the patient’s fibroblasts an altered pattern of Cav1 expression and distribution, with less Cav1 in caveolae membrane fractions, together with a reduced membrane cholesterol concentration and number of caveolae. Electron paramagnetic spectroscopy shows an altered localization of proteins commonly found in caveolae fractions and increased membrane fluidity. Interestingly, Cav1M fibroblasts showed 4-fold increase in exosome secretion. Nanoparticle tracking and TEM analysis revealed a significant reduction in nanoparticle size in Cav1M-derived exosomes. Normal human dermal fibroblasts (HDF) treated to express Cav1M (Cav1M1-159) or exogenously exposed to exosomes isolated from Cav1M fibroblasts showed altered nuclear morphology, exosome secretion profile, proteomics, and miRNA analysis. Our results indicate that mutations in the C-terminus of Cav1 lead to significant cellular alterations at different levels that can lead to morpho-functional features, energetic imbalances, membrane ultrastructure abnormalities, and exosome secretion and signaling alterations. These findings suggest a novel role of Cav1 that links several aspects of cell physiology, from plasma and nuclear membrane dynamics to exocytic behavior, that have potential implications in cellular communication impacting physiology and pathophysiology.

5R01HL091071.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Lack of Sestrins Is Associated with Increased Glycolytic Flux
Authors: Roberson Paul , Johnson Ginger , Jackman Matthew , Libby Andrew , Solt Claudia , Reisz Julie , D' Alessandro Angelo
Published: May 2024

Introduction: Sestrin1, 2, and 3 are a family of stress-response proteins implicated in many diseases. How Sestrins affect cell survival through AMP-activated kinase (AMPK) and protein synthesis through mechanistic target of rapamycin in complex 1 (mTORC1) is most studied; however, how Sestrins affect metabolism is poorly understood. Hypothesis: Independent of AMPK/mTORC1 activation, Sestrins negatively regulate glycolytic flux by inhibiting glycolytic enzyme activity through binding inhibition. Results: Wildtype (WT) HEK293T cells were transfected with plasmids expressing individual FLAG-tagged Sestrins and then deprived of glucose for 180 min or deprived of glucose for 150 min followed by glucose addback for 30 min. FLAG-tagged Sestrins were immunoprecipitated and found to directly interact with Hexokinase2 and Phosphofructokinase such that binding inversely correlates with glucose concentration. Additionally, WT and Sestrin-knockout (TKO) HEK293T cells were subjected to the glycolytic and mitochondrial stress tests and analyzed for metabolic flux via Seahorse analysis. TKO cells demonstrated higher glycolytic flux, but lower mitochondrial flux, compared to WT cells. Cells were then treated with inhibitors against AMPK and mTORC1 and subjected to the glycolytic stress test. Surprisingly, glycolytic flux in TKO cells was unaffected by the inhibitors while WT cells reduced glycolytic flux suggesting Sestrins can regulate glycolytic flux independent of AMPK/mTORC1 activation. Thereafter, WT and TKO cells were glucose-deprived for 120 min or glucose-deprived for 110 min followed by glucose addback for 10 min and then characterized by steady-state metabolomics. As expected, TKO cells possessed elevations in glycolytic metabolites with glucose addback compared to WT cells. Similarly, WT and TKO cells were deprived of glucose for 110 min followed by stable isotope tracing with [13C6]glucose for 10- and 30-minutes and metabolites were profiled by mass spectrometry. TKO cells possessed higher abundances of glycolytic metabolites as well as elevated labeled extracellular lactate. Conclusions: These data support a model wherein Sestrins directly act as negative regulators for glycolytic enzyme activity, thus regulating glycolytic flux.

This work is funded by F32DK126312 (P.A.R.), P30DK048520 Pilot and Feasibility Award (P.A.R.), T32DK120521 (A.E.L.), P30CA046934 Cancer Center Support Grant, R01AR080051 (A.B.), R01DK015658 (S.R.K.), P30DK048520 (P.S.M.).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effect of Sex on the β-Adrenergic Receptor Contribution to Hypoxic Vasodilation
Authors: Bond Braden , Jacob Dain , Shariff Brian , Boyes Natasha , Harper Jennifer , Bostick Brian , Limberg Jacqueline
Published: May 2024

Introduction: Hypoxia elicits peripheral vasodilation to preserve oxygen delivery to tissues. Approximately 10% of hypoxic vasodilation has been attributed to β-adrenergic receptors on the vascular endothelium and smooth muscle. Based on data supporting greater vascular β-adrenergic receptor responsiveness in females compared to males, we examined the effect of sex on the relative contribution of the β-adrenergic receptors to hypoxic vasodilation. We hypothesized β-adrenergic receptor blockade (oral propranolol, 1 mg/kg) would attenuate hypoxic vasodilation and the effect would be greater in females compared to males. Methods: Five female (26±8 yrs, 22±2 kg/m2) and eight male (27±7 yrs, 26±2 kg/m2) participants completed two randomized, single-blinded, and placebo-controlled visits (NCT05256069). On each visit (placebo, propranolol), forearm blood flow (venous occlusion plethysmography) and blood pressure (BP, finger photoplethysmography) were measured during normoxia (SpO2 ~98%) and hypoxia (SpO2 ~80%). Blood flow was normalized for mean BP and expressed as forearm vascular conductance (FVC). The relative change in FVC with hypoxia (%FVC = Hypoxia − Normoxia / Normoxia x 100) was assessed as an index of hypoxic vasodilation. Differences in %FVC between study visits (propranolol − placebo) are reported. Results: %FVC was unaffected by β-adrenergic blockade in female (placebo 15±14%, propranolol -1±15%, p=0.066) and male (placebo 19±25%, propranolol 16±15%, p=0.755) participants. Any effect of β-adrenergic receptor blockade on hypoxic vasodilation did not differ by sex (females: -16±14%, males -3±29%; p=0.383). Conclusion: These preliminary data suggest any effect of β-adrenergic receptor blockade on hypoxic vasodilation does not differ between young healthy female and male participants, although studies are ongoing. Our results further understanding of the effect of sex on vascular control mechanisms during hypoxia.

Funding: AHA 909014 (DWJ), APS-SURF (BJB), HL153523 (JKL).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effects of Electronic vs. Tobacco Cigarettes on Cardiovascular Health in Male and Female Mice
Authors: Lao Candice , Jordan Maria C. , Friedman Theodore C. , Tintut Yin , Shao Xuesi M. , Roos Kenneth
Published: May 2024

Objective: Smoking electronic cigarettes (E-cig) has been promoted as a safer alternative to conventional tobacco cigarettes (CIG) and thus become popular, especially among younger generations. However, one mode of smoking nicotine containing products vs. another on the effects on health and gender are largely unknown. Hypothesis: Both E-cig and CIG have adverse effects on body weight as well as cardiovascular health. Methods: To closely mimic the Western population, we investigated the effects of two insults (diet and/or nicotine exposure) in mice. Nine-week old male and female Apoe−/− mice (C57BL/6 background) were placed on normal chow or high-fat diet (Western diet, WD) and/or exposed to air, E-cig, or CIG for 12 weeks. The E-cig and Cig exposures used a chronic-intermittent puff protocol for 10 hours a day, seven days a week during their active (dark) circadian cycle. Changes in body weight, cardiac structure, function, and atherosclerotic lesions were assessed and compared. Results: In males, body weight was significantly reduced by CIG exposure with both the normal diet or WD, while in females, only on WD. This suggests that CIG exposure had gender-dependent effects on the body weight. E-cig exposure, however, did not affect the body weight in both males and females on either diet compared with the controls. Echocardiographic analysis showed that left ventricular mass was increased while ejection fraction was reduced by both e-cigarette and CIG-exposure. These data suggest that both modes of nicotine delivery had gender-independent adverse effects on cardiac structure and function. En face analysis of the aorta in both genders showed that two insults (CIG and WD) are necessary to induce significantly greater lesions. There were no significant increases in lesions with E-Cigs. This suggests that CIG exposure had insult-dependent but gender-independent effects on atherosclerotic lesion development. Summary: These findings suggest that both electronic cigarettes and conventional tobacco cigarettes impose adverse effects on the body weight and cardiovascular health in modes of nicotine- and gender-dependent manners.

Funding: Department of Defense CDMRP Grant PR 190942 (TCF) and DODCDMRP Grant PR190942-P1 (KPR).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Podocytopathy and Nephrotic Syndrome in Smpdl3b Gene Knockout Mice
Authors: Li Guangbi , Huang Dandan , Ren Jenna , Zou Yao , Kidd Jason , Gehr Todd , Li Pin-Lan
Published: May 2024

Recent clinical studies have shown that downregulation of sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b) in podocytes is a hallmark of idiopathic nephrotic syndrome in children. Meanwhile, there is increasing evidence suggesting that changes of SMPDL3b level in podocytes determine the phenotypes of podocyte injury in glomerular diseases. However, it remains unknown whether SMPDL3b exclusively plays a crucial role in the pathogenesis of podocytopathy and nephrotic syndrome without any other pathogenic stimuli. In the present study, we tested whether Smpdl3b gene knockout induces podocyte injury and nephrotic syndrome in mice. By immunohistochemistry and confocal microscopy, we first confirmed that SMPDL3b was highly expressed in podocytes of wild type (WT) mice but undetectable in these cells of Smpdl3b knockout (KO) mice. Also, Western blot analysis showed that SMPDL3b was not detected in podocytes isolated from Smpdl3b KO mice compared to podocytes of WT mice. Although no significant morphologic changes in glomeruli were observed in Smpdl3b KO mice under light microscope, severe proteinuria and albuminuria were found in Smpdl3b KO mice compared to control littermates. Transmission electron microscopy showed that podocytes of Smpdl3b KO mice had distinctive foot process effacement and moderate microvillus formation and vacuolation. These functional and morphologic changes indicate the development of nephrotic syndrome in mice lacking Smpdl3b gene. In vitro, Smpdl3b gene silencing induced remarkable decrease in podocin levels in podocytes compared to control cells. Phalloidin staining of F-actin showed elevation of cortical actin and reduction of stress fiber in podocytes transfected with Smpdl3b shRNA. Such actin cytoskeleton rearrangement induced by Smpdl3b gene silencing was significantly attenuated by choline but exaggerated by CDP-choline, which are product and substrate of SMPDL3b, respectively. Furthermore, atom force microscopy was used to study mechanical properties of podocytes lacking Smpdl3b gene as the outcome of actin cytoskeleton reorganization. Smpdl3b gene deletion was found to increase podocyte height but decrease cortical elasticity in these cells. Moreover, these pathological changes were markedly inhibited by choline. Taken together, our findings suggest that SMPDL3b is essential for the maintenance of functional and structural integrity of podocytes and that Smpdl3b gene knockout may induce podocytopathy and nephrotic syndrome in mice.

This study was supported by NIH grants DK054927 and DK120491.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
A Role for Septin GTPases in regulating cytoplasmic calcium handling in Drosophila cardiomyocytes
Authors: Tripoli Ben , Petersen Courtney , Smyth Jeremy
Published: May 2024

Proper calcium handling in cardiomyocytes is paramount to maintaining cardiomyocyte contractility and heart function. Data from our lab and others have established that store operated calcium entry (SOCE) is an essential component of cardiomyocyte calcium regulation. SOCE refers to calcium influx that is activated by depletion of endo/sarcoplasmic reticulum (E/SR) calcium stores. The pathway is mediated by STIM proteins, which act as calcium sensors in the E/SR, and ORAI calcium selective influx channels in the plasma membrane. Both upregulation and suppression of SOCE in cardiomyocytes result in cardiomyopathy, demonstrating that proper regulation of cardiomyocyte SOCE is essential. However, the mechanisms responsible for SOCE regulation in cardiomyocytes are not well understood. To this end, septin GTPases have emerged as regulators of SOCE in non-cardiac tissues, with septin 1, 2, or 4 depletion resulting in SOCE suppression and septin 7 depletion resulting in SOCE upregulation. The role of septins in cardiomyocytes is nearly completely unknown. Through intravital imaging analysis of Drosophila heart contractility, we show that cardiomyocyte specific RNAi-based depletion of septins 1, 2, or 4 results in dilated cardiomyopathy nearly identical to that caused by SOCE suppression. Overexpression of SERCA, which pumps Ca2+ into SR stores, reversed the septin 2 phenotype, suggesting a mechanism whereby septin depletion reduces SR Ca2+ store refilling due to suppressed SOCE. In further support of SR Ca2+ store depletion, we found through jRGECO-based Ca2+ imaging of contracting hearts that contractile Ca2+ transients were significantly reduced in septin 2-depleted cardiomyocytes compared to controls. Interestingly, septin 7 suppression resulted in hypertrophic cardiomyopathy like that caused by SOCE upregulation, and micro-computerized tomography (microCT) analysis of heart size further confirmed the hypertrophic phenotype of septin 7 depleted hearts. This septin 7 phenotype was reversed by Orai depletion, supporting a role for SOCE dysregulation in the septin 7 phenotype. These results demonstrate for the first time an essential role for septins in cardiomyocyte physiology involving regulation of Ca2+ homeostasis and cycling.

National institutes of Health.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Diving into old age: exercise and aging affect cardiovascular control in a long-lived mammal, the Weddell seal
Authors: Rambo Ashley H , Mellish Jo-Ann E , Williams Cassondra , Horning Markus , Hindle Allyson G
Published: May 2024

The central component of the mammalian dive response is bradycardia, which, in combination with other physiological mechanisms, conserves intrinsic oxygen stores and facilitates longer submersion. Several factors are hypothesized to affect diving heart rate ( fH) and its variability (HRV) through a shift in autonomic balance. This study aimed to elucidate how dive duration, aging, and exercise influence fH and HRV (calculated as root mean square of successive RR interval differences) of free-ranging Weddell seals ( Leptonychotes weddellii). We expected that mean dive fH and HRV would differ with dive duration, advancing age, and exercise intensity due to a shift in autonomic balance. We collected ECG data from free-ranging female Weddell seals in Erebus Bay, Antarctica (n=10 seals, n=120 dives, age range 9-25 years old). To increase the cost of transport, we affxed a “drag block” to three seals for a portion of their deployment period (n=30 dives). Linear mixed effects model selection identified the effects of dive behavior (duration and depth), seal age, and drag block presence on mean dive fH and HRV. As dive duration increased, mean dive fH decreased (F1,107=227.91, p<0.0001) while HRV increased (F1,103=84.47, p<0.0001), suggesting increased parasympathetic tone. HRV was reduced in older seals (F1,8=8.73, p=0.018), indicating attenuation of parasympathetic influence on bradycardia with advancing age. Consistent with this interpretation, HRV increased with dive duration more steeply in younger animals (age*duration: F1,103=10.31, p=0.002). When exercise effort was experimentally modified by attaching a drag block to free-ranging seals, both mean dive fH (F1,107=6.07, p=0.015) and HRV (F1,103=4.34, p=0.039) were affected; dive HRV was significantly higher when seals dove with a drag block. However, this result should be interpreted with caution until the effects of swimming effort on fH and HRV can be determined. There was a significant interaction between animal age and factors affecting cardiovascular control (age*drag: F1,107=5.16, p=0.028); mean dive fH increased with age when seals did not carry a drag block, but decreased with age when a drag block was present. Taken together, our results point to cardiovascular aging as a physiological element that could affect the foraging ability, fitness, and life history of a long-lived free-ranging mammal.

Funding by the National Science Foundation (#0649609, #0440715, #2020706).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.