bluuebunny/crossref_metadata_2025 huggingface dataset:
The mean tilt of sunspot bipolar regions: theory, simulations and comparison with observations
Authors: Kleeorin N , Safiullin N , Kuzanyan K , Rogachevskii I , Tlatov A , Porshnev S
Published: April 2020

A theory of the mean tilt of sunspot bipolar regions (the angle between a line connecting the leading and following sunspots and the solar equator) is developed. A mechanism of formation of the mean tilt is related to the effect of the Coriolis force on meso-scale motions of super-granular convection and large-scale meridional circulation. The balance between the Coriolis force and the Lorentz force (the magnetic tension) determines an additional contribution caused by the large-scale magnetic field to the mean tilt of the sunspot bipolar regions at low latitudes. The latitudinal dependence of the solar differential rotation affects the mean tilt, which can explain deviations from Joy’s law for the sunspot bipolar regions at high latitudes. The theoretical results obtained and the results from numerical simulations based on the non-linear mean-field dynamo theory, which takes into account conservation of the total magnetic helicity and the budget equation for the evolution of the Wolf number density, are in agreement with observational data of the mean tilt of sunspot bipolar regions over individual solar cycles 15–24.
Accretion disc winds in tidal disruption events: ultraviolet spectral lines as orientation indicators
Authors: Parkinson Edward J , Knigge Christian , Long Knox S , Matthews James H , Higginbottom Nick , Sim Stuart A , Hewitt Henrietta A
Published: April 2020

Some tidal disruption events (TDEs) exhibit blueshifted broad absorption lines (BALs) in their rest-frame ultraviolet (UV) spectra, while others display broad emission lines (BELs). Similar phenomenology is observed in quasars and accreting white dwarfs, where it can be interpreted as an orientation effect associated with line formation in an accretion disc wind. We propose and explore a similar unification scheme for TDEs. We present synthetic UV spectra for disc and wind-hosting TDEs, produced by a state-of-the-art Monte Carlo ionization and radiative transfer code. Our models cover a wide range of disc wind geometries and kinematics. Such winds naturally reproduce both BALs and BELs. In general, sightlines looking into the wind cone preferentially produce BALs, while other orientations preferentially produce BELs. We also study the effect of wind clumping and CNO-processed abundances on the observed spectra. Clumpy winds tend to produce stronger UV emission and absorption lines, because clumping increases both the emission measure and the abundances of the relevant ionic species, the latter by reducing the ionization state of the outflow. The main effect of adopting CNO-processed abundances is a weakening of C iv 1550 Å  and an enhancement of N v 1240 Å  in the spectra. We conclude that line formation in an accretion disc wind is a promising mechanism for explaining the diverse UV spectra of TDEs. If this is correct, the relative number of BAL and BEL TDEs can be used to estimate the covering factor of the outflow. The models in this work are publicly available online and upon request.
Beyond K-complex binary scoring during sleep: probabilistic classification using deep learning
Authors: Lechat Bastien , Hansen Kristy , Catcheside Peter , Zajamsek Branko
Published: April 2020

Study Objectives

K-complexes (KCs) are a recognized electroencephalography marker of sensory processing and a defining feature of sleep stage 2. KC frequency and morphology may also be reflective of sleep quality, aging, and a range of sleep and sensory processing deficits. However, manual scoring of K-complexes is impractical, time-consuming, and thus costly and currently not well-standardized. Although automated KC detection methods have been developed, performance and uptake remain limited.

Methods

The proposed algorithm is based on a deep neural network and Gaussian process, which gives the input waveform a probability of being a KC ranging from 0% to 100%. The algorithm was trained on half a million synthetic KCs derived from manually scored sleep stage 2 KCs from the Montreal Archive of Sleep Study containing 19 healthy young participants. Algorithm performance was subsequently assessed on 700 independent recordings from the Cleveland Family Study using sleep stages 2 and 3 data.

Results

The developed algorithm showed an F1 score (a measure of binary classification accuracy) of 0.78 and thus outperforms currently available KC scoring algorithms with F1 = 0.2–0.6. The probabilistic approach also captured expected variability in KC shape and amplitude within individuals and across age groups.

Conclusions

An automated probabilistic KC classification is well suited and effective for systematic KC detection for a more in-depth exploration of potential relationships between KCs during sleep and clinical outcomes such as health impacts and daytime symptomatology.
The effect of lactose and a prototype Lactobacillus acidophilus fermentation product on digestibility, nitrogen balance, and intestinal function of weaned pigs1
Authors: Acosta Jesus A , Gabler Nicholas K , Patience John F
Published: April 2020

The objective of this study was to determine the effects of lactose (LA) and a prototype Lactobacillus acidophilus fermentation product (FP) on growth performance, diet digestibility, nitrogen (N) balance, and intestinal function of weaned pigs. Twenty-eight newly weaned pigs [approximately 21 d of age; initial body weight (BW) = 5.20 ± 0.15 kg] were housed in metabolism crates and assigned to one of four treatments (n = seven pigs per treatment) corresponding to a 2 × 2 factorial design: with (LA+; 15% inclusion) or without (LA−) LA and with (FP+) or without (FP−) the prototype FP (1 g of FP per kilogram of diet; Diamond V, Cedar Rapids, IA). Feed and water were provided ad libitum. At day 5, pigs were orally given lactulose and mannitol to assess small intestinal permeability. Fecal samples were collected on days 5–9 to determine the apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and N. Total urine output and fecal samples were collected on days 10–13 to determine N retention. On day 15, all pigs were euthanized to collect intestinal lumen and tissue samples. Data were analyzed for the main effects of LA and FP and their interaction using the MIXED procedure of SAS. Lactose improved average daily feed intake (ADFI; P = 0.017), the ATTD of DM (P = 0.014), the ATTD of GE (P = 0.028), and N retention (P = 0.043) and tended to increase the butyric acid concentration in the colon (P = 0.062). The FP tended to increase the digestibility of N (P = 0.090). Neither LA nor the FP affected intestinal barrier function or inflammation markers. The interaction between LA and FP affected intestinal morphology: in the jejunum, pigs fed LA+FP− had increased villus height compared with those fed LA+FP+ and LA−FP−, whereas LA+FP+ was intermediate (interaction P = 0.034). At the terminal ileum, pigs fed LA−FP+ and LA+FP− had increased villus height and villus: crypt compared with those fed LA−FP−, whereas LA+FP+ was intermediate (interaction P = 0.007 and P = 0.007, respectively). In conclusion, the addition of LA brings important nutritional attributes to nursery diets by improving feed intake, digestibility of DM and GE, and the N retention of weaned pigs; however, the functional capacity of LA to improve markers of intestinal function is limited. On the other hand, the FP showed only a mild increase in the digestibility of N but a limited capacity to improve markers of intestinal function.
Immunogenic Modulation of Prostate Cancer to Enhance IL‐27 Immunotherapy Efficacy
Authors: Kumar Shreya , Figueiredo Marxa
Published: April 2020

One of the most common metastatic sites for advanced prostate cancer is bone tissue. Treatment options for bone‐metastatic prostate cancer are currently limited, with immunogenic modulation (IMO) emerging as a possible therapeutic option. IMO involves modulation of cancer cell phenotype by sub‐lethal doses of chemotherapy, making them more susceptible to an immune attack. Such modulation can improve the efficacy of immunotherapeutic agents such as interleukin‐27 (IL‐27). By utilizing the immune system to eliminate tumors, one can effectively reduce chemotherapy toxicity and the associated side‐effects. Moreover, an IMO approach may enable one to treat tumors unresponsive or resistant to chemotherapy. Our main goals for this project are to investigate if prostate cancer cells respond to sub‐lethal doses of chemotherapy drugs through IMO and if IL‐27 immunotherapy can enhance tumor cell killing following IMO. To achieve these goals, we developed a functional assay utilizing immune‐killing in vitro with human prostate cancer cell lines following exposure to varying sub‐lethal concentrations of chemotherapeutics (docetaxel and cabozantinib). Prostate cancer cells co‐cultured with peripheral blood mononuclear cells (PBMCs) and IL‐27 were imaged for 72 h using an Incucyte live‐cell analysis system. A caspase 3/7 green apoptosis reagent was used to quantify apoptosis over time. Immune‐killing is currently being investigated for two human prostate cancer cell lines – PC3 (human prostate cancer adenocarcinoma) and C4‐2B (derivative of human prostatic carcinoma LNCaP). Studies in vivo to profile tumor‐infiltrating immune effectors will help characterize the associated immune response and examine whether chemotherapy and immunotherapy (IL‐27) administered via gene delivery methods can act in synergy to enhance the anti‐tumor immune response while promoting bone repair. We anticipate that such combinational therapy will open new avenues for treating bone‐metastatic prostate cancer while reducing chemotherapy‐associated toxicity and promoting healthy musculoskeletal tissue repair.

Support or Funding Information

R01CA196947
Revisitation of the Work of A Forgotten Comparative Physiologist, Homer W. Smith
Authors: Slivkoff Mark David
Published: April 2020

The death of renowned renal physiologist Homer William Smith in 1962 brought an end to what some have called the “Smithian Era of renal physiology.” Although Dr. Smith’s contributions to renal physiology have been acknowledged most recently in a 2015 article in Physiology Reviews, there has been very little written over the past 50+ years about his extraordinary life. Dr. Smith spent most of his career at the New York University College of Medicine and therefore focused much of his academic energy on human health and disease, but as any reader of his various books knows, Dr. Smith’s research interests involved far more than mammals, and were filled with adventure. That he lucidly communicated his deep knowledge and appreciation of geography, geology, evolution, and physiology brings great meaning not only to his work, but to the discipline of physiology. The purpose of this presentation is to revisit his extraordinary career with an emphasis on his contributions to comparative physiology, as documented through his various research articles and in his most celebrated book, From Fish to Philosopher. His other more philosophical works, including Kamongo and Man and His Gods, will also be discussed. Many physiologists today, similar to Dr. Smith, are tasked with teaching physiology to medical students who lack both the time and interest in learning the evolutionary history of the system under study. Consequently, professors—even those with academic roots in comparative physiology (present author included)—are apt to not enrich their physiology sessions with discussion about how animals other than Homo sapiens “work”, let alone any discussion of who made this knowledge available. There are rich histories to explore to help put the “biology” back into medical physiology. As printed books are disappearing from our medical school libraries, the time is ripe to dig a bit deeper and resurrect the contributions of great biologist storytellers like Homer W. Smith, leading to an enrichment of our students’ learning experiences.

Support or Funding Information

None
Effects of Low‐to‐Moderate Ethanol Consumption on Colonic Cell Proliferation, Differentiation and Apoptosis in Young Adult and Middle‐Aged Rats
Authors: Voutour Luciano , Murase Yuko , Wells Nicole , Quigley Jacqueline , Pascua Jeremy , Pinkowski Natalie , Almaiman Lama , Brasser Susan M. , Hong Mee Young
Published: April 2020

Excessive alcohol consumption is a risk factor associated with colorectal cancer; however, some epidemiological studies have reported that moderate alcohol consumption may not contribute additional risk for developing colorectal cancer while others suggest that moderate alcohol consumption may provide a protective effect that reduces colorectal cancer risk. Prior experimental data have indicated the importance of proliferation, differentiation, and apoptosis as parameters to consider when evaluating colonic cell growth and tumorigenesis. Chemopreventative agents are reported to decrease cell proliferation and to increase differentiation and apoptosis. The present study examined whether chronic low‐to‐moderate ethanol consumption had an effect on these parameters of colonic cell growth. Twenty‐four nondeprived young adult (109 days old) Wistar rats (n=12/group) and twenty‐four nondeprived middle‐aged (420 days old) Wistar rats (n=12/group) were allowed to voluntarily consume a 20% v/v ethanol solution on alternate days for 13 weeks (45 ethanol drinking sessions total) or were given access only to water (non ethanol‐exposed control). The intermittent access 20% ethanol drinking paradigm utilized results in mean blood alcohol levels of ~30–50 mg/dl in the outbred Wistar strain when measured 30–120 min into a standard drinking session. Following the final experimental session, colon tissues were collected for quantitative immunohistochemical analyses of cell proliferation, differentiation and apoptosis using Ki‐67, goblet cell and TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling), respectively. Ethanol treatment resulted in a lower cell proliferation index in both young (P = 0.05) and older (P < 0.001) rats, as well as a lower proliferative zone (P < 0.01 for both ages). Older rats had a shorter colon, but there was no significant difference for proliferation index between young and old rats. Cell differentiation between ethanol‐treated animals and controls was not significant for young rats, but older rats had a lower level of differentiation in the ethanol group. For apoptosis, there was no significant effect of ethanol treatment for either young or old rats. Younger rats had higher values than older rats for both differentiation and apoptosis (P < 0.05). These findings suggest that moderate consumption of ethanol improves at least one notable parameter (cell proliferation) in colonic tumorigenesis regardless of age, however, reduced cell differentiation among older animals.

Support or Funding Information

Support Contributed By: NIH AA023291
Long‐lasting Effects of Early‐life Western Diet and Exercise on Adult Gut Microbiome Composition in Mice
Authors: McNamara Monica P. , Cadney Marcell D. , Singleton Jennifer M. , Ruegger Paul M. , Borneman James , Garland Theodore
Published: April 2020

Increases in availability of energy‐dense foods and simultaneous reductions in physical activity of Western industrialized societies has created an environment that promotes obesity, but alterations in the gut microbiome may also play a role. As with other organismal characteristics, the microbiome may be influenced by factors experienced early in life. We previously demonstrated that early‐life wheel access for 3 weeks, starting at weaning, followed by an 8‐weeks washout period, increases adult wheel running in both selectively bred High Runner (HR) and non‐selected Control (C) lines of mice. We extended these studies by examining effects of early‐life treatments on the gut microbiome. Mice were given early‐life wheel access and/or Western diet from weaning until sexual maturation at 6 weeks of age, then housed individually without wheels and on standard diet until 14 weeks of age, when fecal samples were taken. We profiled the gut microbiome by extracting DNA from fecal samples using MoBio Laboratories PowerSoil DNA Isolation kit, amplified ITS rRNA, sequenced the libraries using an Illumina MiSeq, and chose OTUs using Usearch. For bacterial richness (number of OTUs and Chao1 index) we found a 3‐way interaction of linetype, juvenile Western diet, and juvenile wheel access. These results constitute one of the first reports of juvenile exercise and/or diet having long‐lasting effects on the adult gut microbiome after a substantial washout period (equivalent to ~6 human years).

Support or Funding Information

Supported in part by NIH grant R21HD084856
Human microglia respond to malaria‐induced extracellular vesicles
Authors: Mbagwu Smart , Lannes Nils , Walch Micheal , Filgueira Luis , Mantel Pierre-Yves
Published: April 2020

Background and Objective

Microglia are the chief immune cells of the brain and have been reported to be activated in severe malaria. Their activation may drive towards neuroinflammation in cerebral malaria. Malaria‐infected red blood cell derived‐extracellular vesicles (MiREVs) are produced during the blood stage of malaria infection. They mediate intercellular communication and immune regulation among other functions. During cerebral malaria, the breakdown of the blood‐brain barrier can promote the migration of substances such as MiREVs from the periphery into the brain targeting cells such as microglia. Microglia and extracellular vesicles interactions in different pathological conditions have been reported to induce neuroinflammation. Unlike in astrocytes, microglia‐extracellular vesicle interaction has not yet been described in malaria infection. Therefore, in this study, we aimed at investigating the uptake of malaria‐infected red blood cell derived‐extracellular vesicles (MiREVs) by human microglia cells and their cytokine response.

Method

Human blood monocyte‐derived microglia were generated from buffy coats of anonymous healthy donors using Ficoll‐Paque density gradient centrifugation. The malaria infected red blood cell derived‐EVs (MiREVs) were isolated from the Plasmodium falciparum cultures. They were purified by ultracentrifugation and labelled with PKH67 green fluorescent dye. The internalization of MiREVs by MoMi was observed after 4hours of co‐incubation on coverslips placed in a 24‐well plate at 37°C using confocal microscopy. Cytokine‐gene expression was investigated using rt‐qPCR following the stimulation of the MoMi cells with supernatants from the parasite cultures at 2,4 and 24h respectively.

Results and Conclusion

MiREVs were internalized by the microglia and accumulated in the perinuclear region. MiREVs‐treated cells increased gene expression of the inflammatory cytokine TNFα and reduced gene expression of the immune suppressive IL‐10. Overall, the results indicate that MiREVs may act on microglia which would contribute to enhanced inflammation in cerebral malaria.
Deletion of NEDD4‐2 Abolishes the Inhibitory Effect of High Sodium (HS) Intake on the Basolateral Kir4.1/Kir5.1 of the DCT and Thiazide‐Sensitive Na‐Cl Cotransport (NCC)
Authors: Zhang Dandan , Duan Xin-Peng , Wu Peng , Xiao Yu , Gao Zhong-Xiuzi , Wang Wen-Hui , Lin Dao-Hong
Published: April 2020

Background

We have previously demonstrated that the deletion of NEDD4‐2 increased the basolateral Kir4.1/Kir5.1 channel activity in the distal convoluted tubule (DCT), suggesting the role of NEDD4‐2 in the regulation of basolateral Kir4.1/Kir5.1. Also, it has been demonstrated that dietary sodium intake regulated the basolateral Kir4.1/Kir5.1 channel activity in the DCT such that low sodium (LS) intake stimulated whereas HS intake inhibited the Kir4.1/Kir5.1 channels in the DCT. The HS‐induced inhibition of basolateral Kir4.1/Kir5.1 channels in the DCT was essential for the HS‐induced inhibition of NCC expression/activity because HS failed to inhibit NCC in the kidney‐specific Kir4.1 knockout mice. The aims of the present study are: 1) To explore whether the effect of HS on the basolateral Kir4.1/Kir5.1 in the DCT is compromised in the absence of Nedd4‐2; 2) To examine whether the deletion of Nedd4‐2 abolishes the effect of HS on NCC activity.

Methods

We have used the patch‐clamp methods to measure the basolateral K (Kir4.1/Kir5.1) channel activity of the DCT and DCT membrane potential, and employed renal clearance method to measure thiazide‐sensitive renal sodium excretion in Nedd4l+/+ (WT) mice and renal tubule‐specific Nedd4l−/− mice (Ks‐NEDD4‐2 KO).

Results

We confirmed the previous finding that HS inhibited the basolateral Kir4.1/Kir5.1 channel activity in the DCT and depolarized the DCT membrane and that LS intake increased the basolateral K conductance and hyperpolarized DCT membrane. The deletion of NEDD4‐2 increased the basolateral Kir4.1/Kir5.1 channel activity in the DCT and hyperpolarized DCT membrane. Moreover, the effect of either HS or LS on the basolateral Kir4.1/Kir5.1 channel activity was absent in Ks‐NEDD4‐2 KO mice. Renal clearance experiments showed that LS increased while HS decreased thiazide‐sensitive urinary sodium excretion, indicating the stimulation of NCC and the inhibition of NCC, respectively. The deletion of Nedd4‐2 not only augmented the thiazide‐induced natriuresis but also abolished the inhibitory effect of HS on the thiazide‐induced natriuresis. Furthermore, LS intake failed to further increase thiazide‐sensitive renal sodium excretion. Thus, the effect of HS and LS intake on NCC activity was abolished in Ks‐NEDD4‐2 KO mice.

Conclusion

NEDD4‐2 plays an important role in mediating the inhibitory effect of HS on the basolateral Kir4.1/Kir5.1 channel activity and NCC activity/expression.

Support or Funding Information

DK115366
Pharmacological characterization of a novel, orally available GluN2B antagonist JNJ‐63612445
Authors: Balana Bartosz , Schoellerman Jeffrey , Lord Brian , Wyatt Ryan , Matta Jose , Neff Robert , Welty Natalie , Bhattacharya Anindya , Bonaventure Pascal , Lovenberg Tim , Letavic Michael
Published: April 2020

Introduction

Blockade of GluN2B (NR2B)‐containing NMDA receptors has been proposed as a therapy for a number of neurological and psychiatric diseases including mood disorders. A number of GluN2B antagonists have been identified and developed over the last three decades. These compounds, however, have significant limitations in regard to their selectivity or drug‐like properties (e.g. oral bioavailability).

Methods

The pharmacology of JNJ‐63612445 was explored using in‐vitro assays (calcium mobilization, competitive radioligand binding, electrophysiology), ex‐vivo slice autoradiography and in‐vivo electrophysiology (synaptic transmission and plasticity) and behavior.

Results

JNJ‐63612445 is a high affinity (pKi=8.0), potent (pIC50=7.8) and selective negative allosteric modulator of GluN2B receptors. Upon oral dosing, the compound occupied GluN2B receptors in rat hippocampus in time‐ and concentration‐dependent manner, reaching 50% occupancy at the plasma concentration of 443 ng/ml. JNJ‐63612445 at 1 μM blocked 54% of NMDA receptor‐mediated EPSC in rat neonatal slices similar to other GluN2B antagonists. The compounds at the dose 10 mg/kg s.c. inhibited in vivo long‐term depression measured in the CA1 of anesthetized rats without effects on the basal synaptic transmission. Given orally at the dose 30 mg/kg in mice, the compound significantly reduces immobility time in a tail‐suspension test, while occupying approximately 89% of the GluN2B receptors in the hippocampus.

Conclusions

JNJ‐63612445 represents an example of new generation of potent, selective, and orally available GluN2B antagonists.

Support or Funding Information

Funding information

Authors are full time employees of Janssen Research & Development, LLC. The research was funded by the company.
SPARC: Minimally Invasive Recording of Neural Activity During Natural Voiding in Anaesthetized Rats
Authors: Payne Sophie C. , Osborne Peregrine B. , Keast Janet R. , Fallon James B.
Published: April 2020

Background

Controlling urination with bioelectric neuromodulation devices is an emerging treatment strategy for bladder incontinence/retention as it can be rapidly adjusted to respond to changing patient needs, known as closed‐looped control. However, true closed‐loop bioelectric neuromodulation requires sensing of neural activity to allow accurate and timely delivery of the stimulation to maximally affect the end‐organ. As such, developing a neural recording feedback system that is highly specific for different neural fibre types is a crucial first step towards closed‐loop control.

Objective

To develop and validate a minimally invasive recording technology that differentiates between afferent and efferent neural activity, as well as distinguishing between fast and slow fibre types.

Methods

A custom‐designed, two pair platinum electrode array was implanted onto the pelvic nerve of urethane‐anaesthetised Sprague Dawley rats (male; 8–10 weeks; n=6) with catheterised bladders. Evoked compound action potentials (ECAPs) were generated to confirm placement of the electrode array and cystometry and neural activity recorded during bladder filling and voiding.

Results

ECAPs show recruitment of slow and fast conduction neural populations. Our recording technology distinguished between afferent and efferent activity during the micturition reflex. Within these neural types, distinctive patterns of fast and slow conducting fibres were identified and their firing patterns were consistent with results reported using invasive single‐ and multi‐unit recording techniques.

Conclusion

Closed‐loop bioelectric neuromodulation requires the ability to stimulate or inhibit neural activity, as well as precisely sense ongoing neural activity. We have completed the first step in developing closed loop technology by validating technology that precisely records multiple distinct populations of neural activity using a minimally invasive technique. Future studies will investigate the effectiveness of this recording technique in awake, freely moving rats.

Support or Funding Information

Research reported in this publication was supported by the Office Of The Director, National Institutes Of Health of the National Institutes of Health under Award Number OT2OD023872.
Supplemental arginine improves intestinal morphology, but not expression of enzymes related with synthesis of polyamines in heat stress pigs
Authors: Morales Adriana , González Fernanda , Bernal Hugo , Camacho Lucero , Htoo John K. , González-Vega Caroline , Cervantes Miguel
Published: April 2020

Animals exposed to high ambient temperature suffer heat stress (HS); this condition reduces feed intake and damages their intestinal epithelia, affecting nutrient digestion and absorption. Polyamines are involved in the restoration of intestinal epithelia by stimulating the proliferation of enterocytes. Because arginine is a precursor for the synthesis of polyamines, we examined the effect of supplying extra arginine in the diet on the expression of enzymes involved in polyamine synthesis and the intestinal morphology of HS pigs. This experiment was conducted when natural ambient temperature (AT) fluctuated daily from 28.2 to 38.7 °C. Twenty pigs (25.3±4.4 kg BW) were assigned to one of two treatments: control wheat‐soybean meal diet, and the control diet added with 0.20% free arginine. Pigs were fed at 0700 and 1900‐h, same amount (900 g) each time. At the end of a 21‐d trial, six pigs per treatment were sacrificed to collect intestinal mucosa samples and 5‐cm fragments from duodenum, jejunum, and ileum to analyze the intestinal morphology, and mRNA expression of spermidine/spermine N1‐acetyltransferase (SSAT), ornithine decarboxylase (ODC), and argininosuccinate synthase (ASS). Extra dietary arginine increased the villi height in duodenum, jejunum, and ileum, and the villi height:crypt depth ratio in duodenum and jejunum (P<0.01). However, no effect of extra arginine was observed on the expression of polyamine‐related enzymes (P>0.10). These results indicate that supplementing extra free arginine restores the morphology of the small intestine, but there is no clear explanation for the lack of effect of extra arginine on expression of enzymes involved in the polyamine synthesis.

Support or Funding Information

CONACYT, México, CB‐2016‐01‐287052. Evonik Nutrition & Care GmbH.
The Role of SGS1 Helicase in Mismatch Repair During Single Strand Annealing
Authors: Afreen Faria
Published: April 2020

In humans, interspersed repeated sequences constitute at least 35% of the genome. Single Strand Annealing (SSA) is a repair pathway which occurs when a double strand break is produced between homologous repeats. The product of SSA is a single copy of one of the homologous repeats. As such SSA is a highly mutagenic repair pathway. If an SSA event occurs and consequently deletes important genes such as BRAC2, which itself contains repeats, the result can be catastrophic.

To study mismatch correction (MMC) during SSA, a yeast strain was created to have 7 mismatches (6 base‐pair substitutions and 1‐bp insertion/deletion), resulting in a 3% divergence between the repeats. Previous results show that strains with 3% divergence between the repeats, designated as the F‐A strain, reduced SSA two‐fold compared to the identical strains, designated as the A‐A strain. This reduction in SSA is due to heteroduplex rejection which occurs when the mismatch repair complex, MSH2‐MSH6, recognizes the mismatches in the DNA‐duplex and stimulates the unwinding of the DNA via SGS1 helicase, resulting in cell death. In the absence of heteroduplex, MSH2‐MSH3 will bind branched SSA intermediate, and recruit RAD1‐RAD10 to remove the non‐homologous tails.

Sgs1Δ results in a very efficient SSA repair, with 2 folds increased viability, in both F‐A and A‐A strains, compared to WT strains as SGS1 is required for heteroduplex rejection. Sequencing analysis of sgs1Δ F‐A strain shows an asymmetric gradient of correction favoring the F fragment, similar to the WT strain, suggesting that SGS1 has minimal effects on MMC outcomes. In both sgs1Δ and WT strains tailless strains, there is a uniform correction of MMs, suggesting that the non‐homologous tails influence MMC. All together current data suggests that MMC is more likely to occur during replication, once the SSA repair is completed. Future directions include knocking‐out MLH1, a mismatch repair protein shown to interact with SGS1, and investigating if sectored colonies, cells with unrepaired mismatches is due to replication.

Support or Funding Information

Brandeis Division of Science Summer Research Fellowship
Blood Pressure Maintained in Response to a Hypotensive Stimulus During Mild Acute Inflammation
Authors: Schroeder Elizabeth C. , Hilgenkamp Thessa I. M. , Lefferts Wesley K. , Fernhall Bo
Published: April 2020

Introduction

Severe acute inflammation such as sepsis disrupts autonomic nervous system function and jeopardizes blood pressure regulation. Severe experimental inflammation (endotoxin) blunts the vascular baroreflex to increase muscle sympathetic nerve activity in response to reductions in blood pressure and abolishes baroreflex control of heart rate. Whether mild acute inflammation alters the ability to maintain blood pressure and peripherally vasoconstrict during a hypotensive challenge is unknown.

Purpose

Determine whether mild acute inflammation alters the ability to maintain blood pressure and peripherally vasoconstrict during lower body negative pressure (LBNP).

Methods

Thirteen young, healthy adults (26 ± 4.5 yrs; male n=5; 21.3 ± 2.0 kg/m2) completed assessments before (baseline) and 24h after the induction of acute inflammation via typhoid vaccination. Measures were completed after 10 min rest (rest) and after 2 minutes of equilibration to −20 mmHg of LBNP. Measures included brachial blood flow via ultrasonography and brachial blood pressure and heart rate via an automatic blood pressure cuff. Conductance was calculated as blood flow/mean arterial pressure (MAP). ELISAs were performed on serum blood samples from baseline and 24h to assess inflammatory markers C‐reactive protein (CRP) and interleukin‐6 (IL‐6).

Results

Acute inflammation was evident at 24h by increases in IL‐6 (0.98 ± 0.55 to 1.78 ± 0.68 pg/mL, p<0.01) and CRP (0.42 ± 0.98 to 1.30 ± 1.44 mg/L, p=0.02). Acute inflammation did not alter the blood flow, conductance, diameter, or MAP response to LBNP (see table
, p for interactions >0.05). Blood flow, conductance, and velocity were lower during LBNP compared to rest (p<0.01) whereas brachial diameter and MAP were maintained (p>0.05). Heart rate was elevated at 24h and increased during LBNP at baseline (p<0.01) but did not change during LBNP at 24h (interaction p<0.01).

Conclusion

The ability of young adults to respond to a hypotensive challenge and maintain blood pressure was preserved during mild acute inflammation, however, the heart rate response was altered. Our data may suggest that mild acute inflammation alters baroreflex control of the heart rate response to a hypotensive challenge.

Hemodynamic response to LBNP at baseline and during acute inflammation.

Baseline

24H

p‐value

Rest

LBNP

Rest

LBNP

Visit

LBNP

Interaction

Brachial blood flow, mL/min

47.0 ± 14.4

40.8 ± 11.8

45.4 ± 14.2

42.0 ± 16

0.94

0.04

0.56

Conductance, mL/min/mmHg

52.2 ± 15.5

44.7 ± 11.9

49.8 ± 14.3

46.5 ± 16.6

0.93

0.03

0.46

Brachial diameter, mm

3.81 ± 0.85

3.83 ± 0.87

3.89 ± 0.84

3.81 ± 0.81

0.46

0.62

0.12

Mean velocity, cm/s

7.5 ± 3.3

6.4 ± 2.9

6.8 ± 3

6.4 ± 2.6

0.35

0.04

0.44

MAP, mmHg

90 ± 9

91 ± 8

91 ± 6

90 ± 7

0.81

0.87

0.23

Heart rate, bpm

52 ± 11

57 ± 11

56 ± 12

57 ± 12

0.08

<0.01

<0.01

Data mean ± standard deviation. MAP, mean arterial pressure.
Human Fetuses Accrue Osmotically Inactive Sodium Stores in Anticipation of Birth
Authors: Segar Jeffrey L. , Grobe Connie , Grobe Justin L.
Published: April 2020

Background

Sodium (Na) is stored in the skin and muscle in a non‐osmotic manner. It has been postulated that in adults, these stores protect from water loss and regulate immune function. In post‐weanling rats, osmotically inactive Na pools are mobilized to support growth. The presence of and role for such stores earlier in development have not been explored.

Objective

Determine if osmotically inactive Na pools exist in human infants.

Methods

We utilized literature providing human fetal body composition (Ziegler, EE, 1976) and water compartment distribution (Friis‐Hansen B, 1983) data to calculate changes in total body stores of Na, potassium (K) and chloride (Cl) during fetal development (24–40 weeks gestation). Total body mineral content was estimated by two methods, with calculations based upon 1) body water compartments (BW) and 2) reported mineral content per 100 g fat free mass (MC). Differences between these calculations were interpreted to represent osmotically inactive stores. The content of Na, K and Cl within water compartments were estimated to be 140, 4, and 110 mEq/L (extracellular) and 4, 150, and 10 mEq/L (intracellular), respectively.

Results

Estimates of total body K were nearly identical at each gestational time point (<10% variance; (Kmc−Kbw)/Kmc). Estimated total body Cl by MC exceeded that using BW compartments at all time points, with a maximum difference at 40 weeks gestation of 40 mEq (23% variance). In contrast, total body Na by MC greatly exceeded that calculated based upon BW compartments, with differences increasing from 17 mEq at 24 weeks gestation (variance of 25%) up to 100 mEq at 40 weeks gestation (variance of 35%).

Conclusion

The disproportionate differences in total body mineral content between the two methods coupled with increasing variances at advancing gestational ages suggest that Na, and to a lesser extent Cl, are stored in osmotically inactive pools within the fetus. These pools increase in size with advancing gestational age. As breastmilk is relatively Na‐deficient (10 mEq/L), we speculate the fetal osmotically inactive Na pool is vital to maintain a sufficient total body Na content that is necessary for optimal postnatal growth.
Mesenteric Lymph Derived from Ischemia/Reperfusion Gut Promotes Neutrophil Activation and Lung Infiltration
Authors: Ma Yonggang , Zabell Taylor , Creasy Alexandra , Yang Xiaoyuan , Chatterjee Victor , Yuan Sarah Y.
Published: April 2020

Intestinal ischemia/reperfusion (I/R) can induce systemic inflammation and remote organ injury, where cytokine production and bacteria translocation are traditionally thought to be the major underlying mechanisms. The objective of our study was to determine whether the lymphatic circulation participates in this process. We focused on mesenteric lymph duct, as it drains gut interstitial fluid, proteins, absorbed lipids, and immune cells into the blood circulation through subclavian vein; the lungs are the first organ directly exposed to lymph contents. In a mouse model of intestinal I/R, we found that I/R‐induced lung inflammation, as evidenced by neutrophil infiltration and myeloperoxidase production, was inhibited by mesenteric lymph duct ligation. We then compared the direct effects of lymph collected from pre‐I/R vs. post‐I/R mesenteric lymph duct on isolated neutrophils from normal animals. Flow cytometric analysis revealed that neutrophils treated with post‐I/R lymph exhibited increased surface expression of CD11b. Additionally, upregulated mRNA expression of neutrophil specific chemokines (e.g. Cxcl1, Cxcl2, and Cxcl5) and pro‐inflammatory markers (e.g. Il1b, Il6, and Tnfa) was detected in post‐I/R lymph‐treated neutrophils. These effects were not seen in neutrophils treated with pre‐I/R lymph. Furthermore, because intestinal I/R injury is known to be associated with gut barrier leakage and bacteria translocation into the blood, we thought to determine whether bacteria translocation occurred to the lymphatic circulation during I/R. However, PCR experiments confirmed that all lymph samples tested, regardless of I/R status, were free of bacterial 16s rRNA, excluding the direct involvement of gut bacteria in I/R lymph‐induced neutrophil activation. In conclusion, our study suggests that mesenteric lymph derived from I/R gut contributes to systemic and lung inflammation by activating neutrophils.

Support or Funding Information

The work is supported by the American Heart Association 15SDG22930009 (to YM) and by the National Institutes of Health HL070752 (to SYY).
An siRNA screen for endothelial PAR1‐specific deubiquitinases regulating p38 inflammatory signaling
Authors: Patwardhan Anand , Cheng Norton , Trejo JoAnn
Published: April 2020

Endothelial dysfunction is a hallmark of vascular disease and induced by various inflammatory mediators which signal through GPCRs pathways that are poorly understood. Thrombin induces endothelial inflammatory responses through the activation of protease‐activated receptor 1 (PAR1), a GPCR. Previously, we showed that thrombin‐activated PAR1 is modified by ubiquitin and drives recruitment of transforming growth factor‐β–activated kinase‐1–binding protein 2 (TAB2), an adaptor protein that binds TAB1 to trigger p38‐dependent endothelial barrier disruption, a hallmark of inflammation. However, the regulatory processes that control PAR1‐deubiquitination and associated p38 inflammatory signaling are not known. To fill this gap in knowledge, we sought to identify PAR1‐specific deubiquitinases (DUBs) that removes K63‐linked ubiquitin by conducting an unbiased comprehensive genome‐wide siRNA library screen targeting all 96 human DUB genes in human cultured endothelial cells using multiple PAR1 ubiquitin‐dependent functional readouts. We hypothesize that a PAR1‐specific DUB is essential for terminating thrombin‐induced p38 inflammatory signaling and might be altered in endothelial dysfunction. In an initial screen, endothelial cells were transfected with siRNA pools targeting specific DUBs and PAR1‐ubiquitin dependent responses were assessed. We specifically examined PAR1 cell surface expression, controlled by basal PAR1 ubiquitination, and thrombin‐stimulated p38 activation and downstream inflammatory signaling, which is dependent on agonist‐triggered PAR1 ubiquitination. In preliminary studies have identified several candidates PAR1‐specific DUBs. Currently, we are now investigating the function of top candidate DUBs in regulating the status of PAR1 ubiquitination, cell surface expression and p38 inflammatory signaling. The molecular mechanism responsible for PAR1 deubiquination and relation to controlling the spatio‐temporal dynamics of pro‐inflammatory signaling will be further investigated. Taken together, we anticipate that these studies using a comprehensive siRNA library screening approach will reveal the identity of several DUBS that have important functions in regulating PAR1‐induced ubiquitin driven p38 MAPK endothelial inflammatory signaling.

Support or Funding Information

Authors acknowledge NIH/NIGMS funding support.
Investigating the pathobiology of vocal fold dehydration
Authors: Cox Abigail , Sivasankar Preeti M.
Published: April 2020

Optimal hydration is thought to be necessary for maintaining healthy vocal folds. Whether in vivo systemic dehydration induces vocal fold dehydration is not fully understood. Furthermore, whether systemic rehydration of vocal folds following systemic dehydration has not been investigated. Due to the ubiquitous nature of water in the body, the complex physiological mechanisms in place to maintain body hydration, and the often insensitive markers of hydration status, we set out to design an animal model to study how systemic dehydration affects the vocal folds. The objectives of this study include (1) identifying the optimal animal model for investigations of systemic dehydration and systemic rehydration, (2) developing a reliable and physiologically relevant methodology of systemic dehydration, (3) developing markers of systemic dehydration and (4) demonstrating whether systemic dehydration induces vocal fold dehydration through a combination of methodologies. Sprague Dawley (SD) rats (males and females) and New Zealand White rabbits (males) were used for systemic dehydration and rehydration studies. Rats were systemically dehydrated to an average of 10% reduction in body weight by withholding water. Rabbits were given 5 mg/kg furosemide IP to induce a moderate level of systemic dehydration based on 5% body weight loss. Body weight loss due to dehydration was corroborated by parameters of hemoconcentration. Proton‐density weight MRI at variable dehydration states, genomic analysis of vocal folds, and histopathology were all investigated to determine effects of systemic dehydration. Proton‐density weighted MR imaging can be used to demonstrate that systemic dehydration reliably induces vocal fold dehydration as detected by signal intensity changes. These changes however, are only detected at high body weight loss levels (> 6% body weight loss). Acute episodes of systemic dehydration do not produce reliable, adverse pathological changes to the vocal folds as assessed by histopathology and gene expression studies. Access to water does not induce rehydration if defined by body weight. There are challenges in inducing physiologically‐relevant systemic dehydration and developing a robust and reliable animal model to study the pathobiology of vocal fold dehydration. A combination of techniques are necessary to confirm that dehydration, in an otherwise healthy animal, is occurring; and that dehydration of the body is dehydrating the vocal folds. The sequelae of chronic versus acute dehydration, and systemic dehydration versus surface dehydration also need to be parsed out.

Support or Funding Information

NIH R01DC015545
Human Primary Osteoarthritic Chondrocytes Revert to a Healthier Extracellular Matrix Composition Following Long‐term, Serum‐free, Three‐dimensional Alginate Culture
Authors: Morris Gregory Philip , Popper Hannah , Laird Patrick , Mattioli Patrisia , Healy Andrea , Otto Ashley , Milton LaBraya , Pollard Mark , Miller Lawrence , Behling Kathryn C. , D’Angelo Marina
Published: April 2020

Osteoarthritis (OA) is a common condition involving the loss of articular cartilage which is primarily made up of type II collagen, proteoglycans, and water. In OA, there is an increase in collagenase activity that degrades collagens and proteoglycans necessary for healthy cartilage and leads to the abnormal production of type I collagen. Previous studies in our lab have shown that primary cultures of human osteoarthritic chondrocytes (HOACs) can be reared in serum‐free, three‐dimensional alginate culture and components of the extracellular matrix (ECM) can be measured. However, we had noted that the ECM phenotype of these cells seemed to be changing when cultured past 5 days. In this study, we obtained HOACs from the femoral condyles and the tibial plateau of patients undergoing total knee arthroplasty. HOACs of greater or least pathology, determined by gross observation, were isolated and plated in 12‐well cultures at a density of 1.8 × 106 cells/0.5 mL alginate. Collagens I and II degradation and proteoglycan synthesis were measured in conditioned media and alginate‐associated matrix of the cultures at days 2, 5, 8 and 11. During long term HOAC culture, collagen degradation was reduced (p<0.001 for coll I) while proteoglycans were retained in the ECM. This trend suggests that long term, three‐dimensional, serum‐free culture of HOACs may revert to a healthier phenotype. The largest changes in extracellular matrix production were demonstrated between days 2 and 5 in HOAC culture giving insight of a treatment window to test possible therapeutics.

Support or Funding Information

Support was provided by New Jersey Health Foundation Research Award, Cooper Foundation Research Grant and the Division of Research, PCOM.
A Continuous Fluorescent Assay for β‐Amylase Activity
Authors: Ozcan Kenan , Monroe Jonathan , Berndsen Christopher
Published: April 2020

The production and degradation of starch is key for the survival of plants during the day/night cycle. The stored energy is harnessed through the work of many different enzymes including the β‐Amylase (BAM) family of proteins. BAMs break down long chains of starch into the disaccharide maltose (4‐O‐α‐D‐Glucopyranosyl‐D‐glucose). The model organism Arabidopsis thaliana has 9 β‐Amylase proteins with apparently distinct functions, though not all have the ability to hydrolyze starch. Each BAM seems to have its own unique characteristics, although the specific functional differences are not clear. The objective of our research is to create an assay that can show the kinetics of BAM proteins, that is continuous and sensitive while able to work with synthetic and natural substrates of the BAM proteins. We aim to apply this assay to determine the unique biochemical features of the BAMs. To detect BAM activity, we used a maltose binding sensor composed of Maltose Binding Protein fused to Green Fluorescence Protein (MBP‐GFP). When maltose is bound to MBP it causes conformational changes to GFP resulting in fluorescence. We have tested the assay with maltodextrin chains from 4 to 20 residues in length and with soluble starch finding that we can detect maltose production from all of these substrates with the MBP‐GFP biosensor in the single micromolar range. Moreover, we can detect amylase activity in a continuous measurement format using a plate reader allowing for higher throughput sampling with reduced assay time.

Support or Funding Information

NSF‐RUI MCB‐1616467 to J.M.