bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methocinnamox (MCAM) Reverses and Provides Extended Protection from Fentanyl‐Induced Respiratory Depression in Awake Unrestrained Rats
Authors: Jimenez Victor M. , Maguire David R. , Gerak Lisa R. , France Charles P. 
Published: April 2020

Opioid use disorder affects over 2 million Americans with an increasing number of deaths due to overdose from the synthetic opioid fentanyl and its analogs. Opioid toxicity is due, in large part, to the suppression of respiratory function. The FDA‐approved opioid receptor antagonist naloxone (e.g. Narcan®) is used currently to reverse opioid‐induced respiratory depression; however, its short duration of action limits its clinical utility. Many abused opioids have a duration of action longer than naloxone and reemergence of respiratory depression is common after rescue with naloxone. Methocinnamox (MCAM) is a selective, pseudoirreversible mu opioid receptor antagonist with a long duration of action that may reverse and provide long‐term protection from the respiratory‐depressant effects of fentanyl. Previous research has shown that MCAM reverses and prevents the respiratory‐depressant effects of heroin in nonhuman primates. However, the effects of MCAM on opioid agonist‐induced respiratory depression has not been examined in other species. Moreover, its effectiveness in antagonizing the respiratory depressant effects of intravenous (i.v.) opioids, including fentanyl, has not been examined. This study compared the ability of naloxone and MCAM to reverse and protect from fentanyl‐induced respiratory depression in rats. On different occasions, male Sprague‐Dawley rats (N = 8) received 0.01, 0.032, 0.056, 0.1, or 0.178 mg/kg fentanyl i.v. and ventilatory parameters were recorded using a whole‐body plethysmograph. Fentanyl decreased respiration in a dose‐ and time‐dependent manner. Compared with respiration under control conditions, these doses of fentanyl decreased minute volume by 20–65% with 0.178 mg/kg of fentanyl producing the largest and longest decrease in minute volume. Within 1 minute after i.v. administration, naloxone (10 mg/kg) and MCAM (10 mg/kg) reversed fully the respiratory depressant effects (minute volume) of 0.178 mg/kg fentanyl. The day after antagonist administration, MCAM, but not naloxone, attenuated fully the respiratory depressant effects of 0.178 mg/kg fentanyl. This study extends to another species (rats), another route of administration (i.v.), and another mu opioid receptor agonist (fentanyl) the ability of MCAM to reverse and provide extended protection from the respiratory depressant effects of opioids. Prolonged antagonism by MCAM may provide a useful treatment option for the current opioid crisis, including toxicity from fentanyl and related highly potent analogs.Support or Funding InformationSupported by NIH (R01DA005018 and R01DA048417) and the Welch Foundation (AQ‐0039).
Fresh‐frozen cadaveric dissection for medical students using specimens from surgical CME workshops
Authors: Ehrhardt John Dennis , Woodhouse Palina , Gomez Ferdinand 
Published: April 2020

IntroductionMany medical schools have reduced, modified, or eliminated cadaveric dissection from their curricula. While the digital anatomy paradigm shift allows educators to reinforce concepts in an integrated, longitudinal manner, some students, especially those pursuing surgical specialties, remain interested in cadaver exposure. These students often practice manual dexterity by suturing on poultry and bovine parts, despite its limited ability to simulate human skin and connective tissues. Fresh‐frozen cadaver represents the highest quality specimen for appreciating anatomy and performing dissection. Unfortunately, student access is often prohibited by cost and lack of embalming limits prolonged use.AimWe sought to augment second‐year medical student anatomy knowledge and teach fundamental surgical principles through an elective experience using fresh‐frozen human cadaver.MethodsSurgeons attend continued medical education (CME) workshops with fresh‐frozen specimens to learn advanced operative approaches. Specimens are typically discarded afterwards. Our school’s surgery interest group coordinated with faculty to create a two‐day session focused on head and neck dissection and suturing with fresh‐frozen cadavers leftover from a temporomandibular joint surgery CME workshop. This is a pilot study of an extracurricular supplement at our medical school and was not considered for IRB review.ResultsThis session increased the educational value of donated human specimens. Students highly regarded the event for reinforcing challenging aspects of regional head and neck anatomy. They gained a higher appreciation for tissue planes than afforded by traditional formalin‐preserved cadaver. Dissection and suturing was comparable to what students can expect to encounter in the operating room. All twelve participating students advocated for increasing the size and frequency of these sessions. Formal data collection instruments were not utilized because this was a qualitative pilot experience.ConclusionsFresh‐frozen cadaver can be re‐used by students after surgical workshops for dissection and suturing to ethically gain the most educational value out of donated human specimens. These elective sessions can be dispersed throughout an integrated preclinical curriculum, each focused on a different anatomic region. The tactile experience of working with fresh‐frozen specimens is superior to formalin‐preserved tissues and enhances the education of students interested in the surgical profession.
Protective Effect of Diminazene Aceturate in Acid‐Induced Airway Obstruction
Authors: Liao Yan-Shin , Kuan Shin-Ping , Guevara Maria Valentina , Collins Emily , Atanasova Kalina , Dadural Joshua , Vogt Kevin , Schurmann Veronica , Reznikov Leah R. 
Published: April 2020

Mild airway acidification occurs in several airway diseases, including cystic fibrosis and asthma. However, the role of airway acidification in airway pathology is controversial. Here, we studied mucus secretion in piglets forty‐eight hours following an intra‐airway acid challenge. Airway submucosal glands of acid‐challenged piglets exhibited faulty submucosal gland secretion, with a retainment of mucin 5B (MUC5B) in the submucosal gland and decreased concentrations of MUC5B in lung lavage fluid following cholinergic stimulation. Concomitantly, intrapulmonary airways were obstructed with glycoprotein rich material under both basal and methacholine‐stimulated conditions. Blocking detection of acid with the diminazene aceturate, a small molecule that inhibits the acid‐sensing ion channel (ASIC), partially restored submucosal gland function and mitigated acid‐induced airway obstruction. These findings suggest that transient airway acidification significantly impacts mucus secretion and highlight diminazene aceturate as an agent beneficial in alleviating some mucus defects.Support or Funding InformationHL119560, 1OT2OD023854
Role of O‐GlcNAcylation in SEC24C function
Authors: Lamb Caitlin , Bisnett Brittany , Cox Nathan J. , Smith Tim , Boyce Michael 
Published: April 2020

Coat protein complex II (COPII) mediates forward protein and lipid cargo trafficking from the endoplasmic reticulum via five protein components required for in vitro vesicle formation: SAR1, SEC13, SEC23, SEC24, and SEC31. While the structure and function of COPII proteins are well understood, we do not fully understand how COPII is regulated in response to environmental and cellular stimuli. We and others have found that O‐linked‐beta‐N‐acetylglucosamine (O‐GlcNAc), a dynamic single‐sugar modification added to serines and threonines of intracellular proteins, decorates many human COPII components, including all four SEC24 paralogs. Additionally, others have shown that COPII, and specifically SEC24, may play a role in the formation of the autophagosome for autophagy, a process in which the cell degrades its own components. However, the regulation of SEC24’s canonical and autophagic functions remains unclear. To determine the function of SEC24 O‐GlcNAcylation, we mapped O‐GlcNAc sites on SEC24C using mass spectrometry and created unglycosylatable serine or threonine to alanine mutations at each O‐GlcNAc site. We then used CRISPR‐Cas9 to create SEC24C−/− HEK 293T and HeLa cells, and reintroduced unglycosylatable SEC24C mutants. By comparing SEC24C−/− to control HeLa cells, we discovered a baseline difference between levels of autophagy. Furthermore, SEC24C−/− 293T cells may be more sensitive to ER stress than control cells are. With these differences between SEC24C −/− and control cells, we will next determine whether the differences persist when comparing the unglycosylatable mutants to wild type SEC24C, using Western blots and immunoprecipitation. This study will enhance our understanding of the role of O‐GlcNAcylation on SEC24C function and the interplay between canonical COPII function and autophagy.Support or Funding InformationResearch on this project in the Boyce Lab is supported by NIH grant 1R01GM117473.
Development of Functional, Contractile 3‐D Human Muscle Constructs for Studies of the Effects of Microgravity on Muscle Mass and Function.
Authors: Jones Samantha W. , Janvier Adam J. , Shigdar Shahjahan M. , Henstock James R. , McArdle Chris , Hoettges Kai , McArdle Anne , Jackson Malcolm J. 
Published: April 2020

Major demographic changes are affecting modern societies, leading to rapidly increasing numbers of older people with relatively poor health and quality of life. The mechanisms underlying age‐related loss of muscle have not been fully evaluated, but we have previously demonstrated that muscle from ageing animals and humans show attenuated adaptations to exercise that compromises their ability to maintain muscle mass and function. We have evaluated key mechanisms underlying adaptations of skeletal muscle to exercise and demonstrated that the exercising muscle of young or adult animals and humans generates reactive oxygen species (ROS) that stimulate activation of specific transcription factors leading to increased generation of a number of protective and cytoprotective proteins. Such responses do not occur in muscle from older animals and man in response to exercise. Astronauts and animals exposed to microgravity also lose skeletal muscle mass and their muscles are also relatively unresponsive to aerobic or resistance training in microgravity. Within a call from the UK Space Agency for an upcoming national mission on board the International Space Station (ISS), we will utilise in vitro studies of 3‐D skeletal muscle constructs to determine whether an analogous failure of muscle adaptations to contractile activity occurs in muscle fibres exposed to microgravity as that which occurs in older people on earth. The aim of the current study was to develop appropriate 3‐D constructs which remained viable and contractile following field electrical stimulation in specifically designed, sealed hardware for space flight for up to 7 days. Initial experiments examined a variety of immortalised and primary murine myocytes which were found unsuitable due to lack of excitability and high oxygen consumption. Subsequent experiments have utilised immortalised human myocytes obtained from Dr. Vincent Mouly (Paris, France) which have been fabricated on 3D printed scaffolds encapsulated in a fibrin hydrogel solution (4×106 cells/construct) and polymerised at 37°C. Once matured the constructs were checked for contractility and the medium was replaced with Leibrovitz‐L15 medium (supplemented with 2 mg/mL 6‐aminocaproic acid) to minimise oxygen consumption while retaining viability. These constructs retain viability and contractility for up to 7 days and display significant adaptations to short periods of contractile activity in normal gravity. Specific hardware to maintain the constructs and permit electrical stimulation of contractions has been designed by Kayser Space Ltd., (Harwell, UK), and the experiment will fly to the ISS in 2021.Support or Funding InformationSupported by the UK Space Agency
Ecm16 protein confers resistance against the DNA intercalator antibiotic echinomycin
Authors: Gade Priyanka R. , Erlandson Amanda , Mathews Irimpan I. , Chen Xi , Mera Paola , Kim Chu-Young 
Published: April 2020

Echinomycin is a nonribosomal peptide antibiotic that acts by intercalating double‐stranded DNA. The echinomycin biosynthetic gene cluster of Streptomyces lasaliensis contains a gene of unverified function, ecm16. We show that expression of Ecm16 in the echinomycin‐sensitive E. coli K12 renders cells resistant to echinomycin. Additionally, we have determined the X‐ray crystal structure of Ecm16 at 2.0 Å resolution. Interestingly, the three‐dimensional structure of Ecm16 resembles that of UvrA, the DNA damage sensor protein from the prokaryotic nucleotide excision repair pathway. Ecm16, like UvrA, contains two nucleotide binding domains on a single polypeptide chain, and it can bind double‐stranded DNA. However, our results show that neither UvrA nor Ecm16 can complement each other’s function in vivo.Support or Funding InformationThe University of Texas System STARs Award
Evaluation of Hindlimb Arteriolar Vasodilation Evoked by Dynamic Muscle Contraction in Goto‐Kakizaki Rats Using in vivo X‐ray Microangiography
Authors: Sonobe Takashi , Tsuchimochi Hirotsugu , Pearson James T. 
Published: April 2020

Vascular endothelial dysfunction is a well established comorbidity in diabetes mellitus. In peripheral resistance arteries, it has been reported that endothelium‐dependent hyperpolarization (EDH), which is an important factor to induce vasodilation in small arteries, is downregulated in diabetic animals. We hypothesized that downregulation of EDH inhibits exercise‐induced vasodilation in diabetic patients and causes exercise intolerance. To test this hypothesis, the objective of this study was to evaluate peripheral vascular function in response to muscle contraction and the contribution of EDH to vasodilation in anesthetized diabetic rats. Type 2 diabetic Goto‐Kakizaki (GK) rat and healthy Wistar rat were anesthetized by urethane + α‐chloralose, and then mechanically ventilated. Carotid artery and jugular vein were cannulated for monitoring blood pressure and administering pharmaceutical agents. By means of X‐ray angiography, the hindlimb vasculature was visualized by infusing iodine contrast agent via the catheter inserted into the femoral artery. Angiography was performed before and after rhythmic muscle contraction (0.5 s tetanic contraction + 0.5 s relaxation, repeated 30 times) evoked by sciatic nerve stimulation (40 Hz, 0.1 ms duration). Femoral blood flow was simultaneously monitored by a transit‐time ultrasonic flowmeter. To investigate the contribution of EDH to the changes in arterial diameter and vessel recruitment, angiography was repeated after an intravenous administration of small conductance and big conductance potassium channel inhibitors (50 μg/kg apamin+charybdotoxin), which are known to suppress the EDH‐dependent vasodilation.We observed increases in arterial diameter (~100% increase) in most of hindlimb arteries after the muscle contraction except for the superficial artery and the saphenous artery. We also observed recruitment of small arteries (diameter less than 100 μm), which were not visualized at baseline condition. These vasodilative effects on the hindlimb arteries were similar in GK rat compared to Wistar rat. Increase in femoral blood flow at peak and decrease in vascular resistance at the nadir were also similar between the groups. Inhibition of potassium channels did not affect baseline diameter in arteries and the changes in vasodilation after muscle contraction in either Wistar or GK rats. In conclusion, effects of acute muscle contraction on the changes in arterial diameter and recruitment were preserved in the GK rat. EDH may not contribute to induce the peak response in arterial diameter after muscle contraction.Support or Funding InformationThis work was supported by Grants‐in‐Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan [18K10882].
Myeloid‐Specific STAT4 Deletion Improves Glucose Homeostasis in Diet‐Induced Obesity
Authors: Hossain Sakib , D’silva Melinee , Nadler Jerry L. 
Published: April 2020

The signal transducer and activator of transcription 4 (STAT4) is activated in response to IL‐12 and stimulates expression of genes necessary for T helper 1 cell differentiation. Recent evidence has suggested that STAT4 is involved in an inflammatory cascade leading to atherosclerosis and insulin resistance in mouse models. However, the role of STAT4 in myeloid cell functions has not been studied. IL‐12 and STAT4 is expressed in the pancreatic beta cell and therefore changes in activity could lead to altered glucose homeostasis as typically seen in type 2 diabetes (T2D). For this reason, elucidation of cell‐specific roles of STAT4 on glucose homeostasis is critical for treatment and prevention of T2D. Previous studies have shown that global STAT4 deletion significantly improves insulin signaling and glucose tolerance in high fat fed C57Bl6 mice. This study was undertaken to determine the role of myeloid specific STAT4 deletions on glucose homeostasis and islet function. We developed a novel mouse model with targeted deletion of STAT4 in myeloid cells. Here we show that high fat fed C57Bl6 mice with macrophage specific STAT4 deletion (STAT4 LysmCre) display improved glucose metabolism compared to control mice. After 16‐weeks, control mice gained an average of 24.5 grams while the STAT4 LysmCre cohort gained an average of 20 grams, indicating only moderate differences in weight gain. However, STAT4 LysmCre mice showed an improved glucose tolerance compared to control mice [AUCGlucose 68780±2820 vs. 56025±6687 (mg/dl)*min]. These results may suggest that STAT4 signaling in myeloid cells plays a key role in glucose homeostasis during high fat feeding. Further studies in progress will explore the role of myeloid STAT4 deletion on pancreatic beta cell function.Support or Funding InformationThis research is being funded by NIH grant 5R01HL142129‐02
Hidden cardiotoxicity of drugs ‐ paradigm change in cardiac safety testing in ischemic and comorbid conditions
Authors: Ferdinandy Peter 
Published: April 2020

Unexpected cardiac adverse events are one of the leading causes of interruption of clinical trials and drug withdrawals. It has been shown that cardiovascular risk factors and comorbidities (such as aging, metabolic diseases, etc) and their medications (e.g. nitrates, antidiabetic drugs, statins, etc) may interfere with cardiac ischemic tolerance and molecular signaling of endogenous cardioprotection. Indeed certain drugs may exert adverse events on the diseased heart that is hidden in the healthy myocardium. Hidden cardiotoxic effects of drugs may occur due to (i) enhancement of unwanted signaling due to ischemia/reperfusion injury and/or the presence of risk factors and/or (ii) inhibition of cardioprotective signaling pathways, both of which may lead to ischemia‐related cell death and pro‐arrhythmic events. This led to novel concept of “hidden cardiotoxicity”, i.e. cardiotoxicity seen only in the diseased heart, i.e. ischemia/reperfusion injury and/or its major comorbidities (Ferdinandy et al, Eur Heart J, 2019). Hidden cardiotoxicity cannot be revealed by the routinely used cardiac safety testing methods in “healthy” test systems, moreover, the mechanism of hidden cardiotoxocity is largely unknown. Therefore, here we summarize the current knowledge on hidden cardiotoxicity and urge the need for development of novel cardiac safety testing platforms for early detection of yet “hidden” cardiotoxicity. We also show an example of rofecoxib a COX2 inhibitor with hidden cardiotoxic properties.Support or Funding InformationThis study was supported by the National Research, Development and Innovation Office of Hungary (NKFIH; NVKP‐16‐1‐2016‐0017 National Heart Program). The research was also financed by the Higher Education Institutional Excellence Programme of the Ministry of Human Capacities in Hungary, within the framework of the Therapeutic development thematic programme of the Semmelweis University
Acetylation‐phosphorylation cross‐talk: A role for HDACs in the regulation of PKCdelta/theta phosphorylation
Authors: Habibian Justine S. , Bolino Matthew , Ferguson Bradley S. 
Published: April 2020

Post‐translational modifications (PTMs) such as acetylation and phosphorylation have been implicated in contractile dysfunction and muscle wasting. Moreover, mounting evidence demonstrates that histone deacetylase (HDAC) inhibitors attenuate muscle wasting in animal models of disuse and muscular dystrophy. Historically, lysine acetylation was studied in the regulation of gene transcription, where for instance HDACs remove acetyl groups on lysine residues of histone proteins to suppress gene expression. However, recent evidence has shown that non‐histone proteins are also regulated by acetylation; functioning in protein stability, intracellular signaling, mitochondrial function and muscle contraction. Despite our current understanding for lysine acetylation and protein phosphorylation in muscle, how these PTMs cross‐talk to regulate muscle physiology remains unclear. In our attempt to understand acetylation‐phosphorylation cross‐talk, we examined the role for HDAC inhibitors on protein kinase C delta (PKCδ) and delta/theta (PKCδ/θ) phosphorylation. PKC is composed of multiple isoforms and its activation has been linked to muscle disease and dysfunction. Myotubes were treated with or without a pan‐HDAC inhibitor (trichostatin A; TSA) in the absence or presence of a pathological agonist (i.e. PMA). Phorbol 12‐myristate 13‐acetate (PMA) increased phosphorylation of PKCδ and PKCδ/θ. Interestingly, PMA‐induced PKCδ and PKCδ/θ phosphorylation was amplified in myotubes treated with the pan‐HDAC inhibitor TSA. Class selective HDAC inhibitors confirmed these findings and further demonstrated that inhibition of class I HDACs (HDAC1, 2, 3) was sufficient to increase PKCδ and PKCδ/θ phosphorylation. It should be noted that total PKCδ and PKCδ/θ protein expression increased with class I HDAC inhibition concomitant to the increase in protein phosphorylation. These data suggest that HDAC inhibition increases total PKC gene/protein expression that can then be phosphorylated. Finally, we report that the HDAC 1/2 selective inhibitor Romidepsin also increased total and phosphorylated PKCδ and PKCδ/θ in response to PMA. Genetic knockdown studies are currently underway to elucidate the specific HDAC that regulates PKC gene/protein expression, while chromatin immunoprecipitation (ChIP) is being used to determine HDAC binding to the PKC promoter. Lastly, elucidating a functional consequence for HDAC inhibitor‐mediated regulation of PKCδ and PKCδ/θ protein expression and phosphorylation in muscle could yield significant insight into muscle wasting and function.Support or Funding InformationThis work is supported by the USDA NIFA (Hatch‐NEV00727, Hatch‐NEV00767), the Dennis Meiss & Janet Ralston Fund for Nutri‐epigenetic Research, the National Institute for General Medical Sciences (NIGMS) of the NIH (P20 GM130459) and the National Heart, Lung, and Blood Institute of the NIH (R15 HL143496) and NSF EPSCOR Track II (OIA‐1826801) to B.S.F.