bluuebunny/crossref_metadata_2025_split huggingface dataset:
One Session of High‐Intensity Interval Training Acutely Enhances the Sensitivity of Cerebral Vasoreactivity Post‐Exercise in Young Healthy Males
Authors: Martinez Mauricio , Salvador Paolo , Schoech Lauren , Clark Cayla , Gonzales Joaquin U. , Rivas Eric 
Published: April 2020

BackgroundCardiorespiratory fitness and exercise training are associated with improved cerebral vasoreactivity of the middle cerebral artery (MCAvmean). High‐intensity interval exercise training (HIIT) is an effective time‐efficient alternative to long‐duration lower‐intensity exercise that offers similar vascular benefits. It is currently unclear whether HIIT acutely alters cerebral cerebrovascular function.PurposeThis project tested the hypothesis that a single session of HIIT would enhance cerebrovascular reactivity after exercise.MethodsFive healthy active (7‐day activity: 9140±3525 steps·day; VO2max: 55±6.3 mLO2·kg·min−1) adults (22.4±1.9y, 175.9±5.1cm, 77.1±5.1kg) completed one session of HIIT exercise comprised of four bouts of four‐minute intervals at 65% watt max (between 85–95% maximal heart rate [HR]) with three‐minute recovery between at 15% watt max (between 50–65% HRmax). Transcranial Doppler MCAvmean assessed hypercapnia induced cerebral vasoreactivity using a three‐minute rebreathing technique in a supine rest position, before and 30‐minutes after the HIIT. Dose‐response curves (non‐linear log‐transformed) examined the sensitivity of cerebral vasoreactivity to increased concentrations of the partial pressure of end‐tidal CO2 (Torr). Parameters derived from the dose‐response curve included half‐maximal effective concentration (EC50), LogEC50, and HillSlope. Systemic hemodynamics including mean arterial pressure (MAP), systemic vascular resistance (SVR) and HR were also measured during the rebreathe test. MCAvmean cerebral vascular conductance (CVC) was calculated by MCAvmean/MAP. Paired t‐tests were used to compare the pre‐ to post‐HIIT changes in parameters. Alpha prior was set at P<0.05.ResultsThe sensitivity of cerebral vasoreactivity improved from pre to post‐HIIT exercise as reflected by lower MCAvmean EC50 (Δ3.0±1.5 Torr, P<0.006) and LogEC50 (Δ0.03±0.02 Log Torr, P<0.008) post‐exercise. MCAvmean HillSlope showed a trend for significance (P<0.06). Systemically, MAP (Δ9.6±7.7 mmHg, P<0.02) and SVR (Δ343.2±242.5 dynes·s1·cm5, P<0.002) were both lower and HR (Δ18±7 b/min, P<0.002) was increased post‐exercise. When accounted for post‐exercise hypotension, MCAvmean CVC EC50 (Δ4.2±2.0 Torr, P<0.007) and LogEC50 (Δ0.04±0.02 Log Torr, P<0.001) were also improved post‐exercise; however, MCAvmean CVC HillSlope was not different (P=0.30) between conditions.ConclusionThese preliminary data suggest that a single session of HIIT exercise may improve the sensitivity of cerebral vasoreactivity in young healthy males. This may in part be due to changes in peripheral hemodynamics such as baroreflex mediated alterations in MAP, SVR, and HR post‐exercise. These preliminary findings give insight into an integrative relationship between cerebral and peripheral blood flow during recovery from high‐intensity exercise and the benefits of HIIT on cerebrovascular health.
Inhibition of Spinal Inflammation Restores Compensatory Plasticity Induced by Recurrent Reductions in Respiratory Neural Activity in Offspring Exposed to Gestational Intermittent Hypoxia
Authors: Mickelson Carly R. , Gumnit Maia G. , Meza Armand L. , Radcliff Abigail B. , Watters Jyoti J. , Baker Tracy L. 
Published: April 2020

Sleep disordered breathing (SDB) during pregnancy is increasing in parallel with the obesity epidemic, yet the long‐term effects on the adult offspring are unknown. In our animal model of SDB during pregnancy, pregnant rats are exposed to chronic intermittent hypoxia (8 hrs/day, 2 min 10.5% O2 separated by 2 min of 21% O2) or intermittent normoxia from gestational days 10–21. Preliminary data show that adult male (but not female) offspring exposed to gestational intermittent hypoxia (GIH) show deficits in respiratory control that manifest as increased spontaneous central apneas during presumptive sleep and impaired compensatory responses to recurrent reductions in respiratory neural activity, a form of plasticity known as inactivity‐induced inspiratory motor facilitation (iMF). Preliminary data also show that microglia isolated from male GIH offspring show primed inflammatory responses in respiratory control regions. Since neuroinflammation impairs respiratory plasticity, we tested the hypothesis that inhibiting NF‐kappaB and STAT3 inflammatory transcription factor activation restores the capacity to elicit iMF in GIH offspring. Phrenic inspiratory output was measured in urethane‐anesthetized, vagotomized, mechanically ventilated GIH or gestational intermittent normoxia (GNX) offspring. Vehicle or 2‐[(aminocarbonyl)amino]‐5 ‐(4‐fluorophenyl)‐3‐ thiophenecarboxamide (TPCA‐1) was delivered intrathecally over the phrenic motor pool ~1 hour before exposure to recurrent reductions in neural activity (5, ~1 min neural apnea episodes, separated by 5 min). As expected, recurrent neural apnea elicited a significant increase in phrenic inspiratory output in vehicle‐ and TPCA‐treated GNX offspring (54±17% and 62±12% baseline, n=6, 5, respectively, p<0.05) when compared to time controls not receiving activity deprivation (11±4% baseline, n=4). By contrast, recurrent neural apnea did not elicit iMF in vehicle‐treated GIH offspring (25±3%, n=7, p>0.05). However, in GIH offspring receiving intrathecal TPCA‐1, recurrent neural apnea induced a significant increase in phrenic inspiratory output (75+/−10% baseline, n=7, p<0.05), indicating that NF‐kappaB and STAT3 inflammatory transcription factor inhibition rescues the capacity to elicit iMF in GIH offspring. These data indicate that increased neuroinflammation in male GIH offspring impairs the capacity for recurrent reductions in respiratory neural activity to trigger compensatory forms of neuroplasticity.Support or Funding InformationSupported by R01HL142752 (JJW and TLB)
Development of a hands‐on learning activity on potential DNA damage and skin cancer for a nursing biochemistry class
Authors: Paliwal Vipin , Masoud Nazieh , Nickel Anne-Marie 
Published: April 2020

Skin cancer (basal cell carcinoma) is one of the most common forms of cancer in the US (about 4.3 million cases/year). Prolonged exposure to sunlight is one of the major causes of skin cancer due to mutations in the DNA. Ultraviolet‐B (UV‐B) radiations in the region of 290–320 nm of the solar spectrum are absorbed by basal keratinocyte cells resulting in mutated DNA leading to cancer. We developed a two‐part active learning experience for the nursing biochemistry class. Part I: In this activity, the relative intensity of UV radiation at 308 nm in the absence and presence of sunscreen was measured using a UVX Digital Radiometer‐UVX31 Sensor by first‐year nursing students in a biochemistry course at the Milwaukee School of Engineering (MSOE). A class of 20 students brought in their own commercially available sunscreens to class. Students tested the sunscreens’ ability to block the UVB light. A thin layer of sunscreen was applied to a plastic wrap sheet and placed between the UV source and the sensor. Students compared the intensity of the UV light (in mW/cm2) transmitted through an uncoated and coated plastic wrap. They then observed that different commercial sunscreens have different abilities to block UV light.DNA damage by UVB causes mutations due to the development of cyclobutane‐pyridine photodimers commonly recognized as thymine‐thymine (T‐T) dimers. Part II: Students made connections between the real‐life classroom activity performed in Part I and a three‐dimensional physical model of DNA segment (crystal structure source entries: ndb UD0053 or PDB 1SM5) showing the formation of the T‐T dimer using a hand‐held model and images. The model was constructed by 3D‐printing. Students were challenged to locate the T‐T dimers in the model and discuss the possible impact of the change in the DNA structure.The activity motivated the nursing biochemistry students and enhanced their learning experience with DNA mutations by directly relating it to everyday products such as sunscreens and a 3‐D model showing the biochemical DNA damage which could lead to skin cancer. Additionally, the two‐part activity enhanced one‐on‐one student‐faculty interactions in the classroom. In the future we plan to conduct an in‐depth quantitative educational study to understand the benefits of this active learning exercise as compared to traditional classroom instruction.Support or Funding InformationSummer professional development grant, Milwaukee School of Engineering, Milwaukee, WI. Center for BioMolecular Modeling (CBM), Milwaukee School of Engineering, Milwaukee, WI.
A Combination Therapy of Cisplatin and Lovastatin Reduces Ras Activation in an A375 Melanoma Cell Line
Authors: Shock Nicole Kuss , Byrd Shere K. 
Published: April 2020

In many cancers mutations in the Ras protein lead to cancer growth and metastasis. In a mutated form, Ras allows cells to avoid a normally programed death called apoptosis. Ras is a GTP‐binding protein and attaches to the cell membrane through a prenylated tail. When attached, it will activate and signal for the promotion of cell survival. The prenylated tail and membrane insertion will keep Ras in its activated state. Typical antineoplastic agents are highly toxic therapies, but by using them in combination with alternative therapies such as lovastatin, proliferating cells may be held in check with reduced side effects. The purpose of these experiments was to examine Ras prenylation and activation in a melanoma cell line, following treatment with a combination of lovastatin and cisplatin. Flow cytometry using annexin‐V apoptosis assay was performed to determine drug toxicities for each drug and in combination. Melanoma cells were treated for 48 with 10 uM lovastatin, then 1.5 ug/ml cisplatin was added for an additional 24 hr. Membrane localization of Ras was determined using immunohistochemistry followed by analysis with ImageJ software. The results show that Ras localization to the membrane in cells undergoing the combined treatment was reduced 4‐fold relative to cisplatin alone (p<0.05). These results indicate that statin therapy combined with traditional cancer drugs such as cisplatin may be more effective at slowing cancer growth with lower toxicities, than with cisplatin alone.Support or Funding InformationSupported by the NIH Common Fund, through the Office of Strategic Coordination, Office of the NIH Director with the linked awards: TL4GM118992, RL5GM118990, & UL1GM118991 and a Fort Lewis College Undergraduate Research Grant.
Mgr2 regulates membrane insertion of marginal stop‐transfer signals in the mitochondrial inner membrane
Authors: Lee Seoeun , Kim Hyun 
Published: April 2020

The TIM23 complex mediates membrane insertion of presequence‐containing mitochondrial proteins via a stop‐transfer mechanism. Stop‐transfer signals consists of a hydrophobic transmembrane segments and flanking charges. Mgr2 functions as a lateral gatekeeper of the TIM23 complex. However, it remains elusive which features of stop‐transfer signals are discriminated by Mgr2. To determine the effects of Mgr2 on the TIM23‐mediated stop‐transfer pathway, we measured membrane insertion of model transmembrane segments of varied hydrophobicity and flanking charges in Mgr2 deletion or overexpression yeast strains. We found that upon deletion of Mgr2 the threshold hydrophobicity for membrane insertion or the requirement for matrix‐facing positive charges are reduced. These results imply that Mgr2‐mediated gatekeeper function is important to control membrane sorting of marginal stop‐transfer signals.Support or Funding InformationThis research was funded by grants from National Research Foundation of Korea (NRF‐2016R1A2B2013459) and Promising‐Pioneering Research Program through Seoul Nation University to HK. Work in the laboratory of MvdL is supported by the Deutsche Forschungsgemeinschaft (SFB 894, IRTG 1830). Work in the laboratory of RI is supported by the CNRS ATIP program.
Predicting nitroimidazole antibiotic resistance mutations in Mycobacterium tuberculosis with protein engineering
Authors: Lee Brendon , Almeida Deepak , Afriat-Jurnou Livnat , Aung Htin , Forde Brian , Harold Liam , Hards Kiel , Pidot Sacha , Ahmed Hafna , Mohamed Elaaf , Taylor Mathew , West Nicholas , Stinear Timothy , Greening Chris , Beatson Scott , Cook Gregory , Nuermberger Eric , Jackson Colin 
Published: April 2020

Our inability to predict which mutations could result in antibiotic resistance has made it difficult to rapidly identify the emergence of resistance, identify pre‐existing resistant populations, and manage our use of antibiotics to effectively treat patients and prevent or slow the spread of resistance. Here we investigated the potential for resistance against the new antitubercular nitroimidazole prodrugs pretomanid and delamanid to emerge in Mycobacterium tuberculosis, the causative agent of tuberculosis (TB). Deazaflavin‐dependent nitroreductase (Ddn) is the only identified enzyme within M. tuberculosis that activates these prodrugs, via an F420H2‐dependent reaction. We show that the native menaquinone‐reductase activity of Ddn is essential for emergence from dormancy, which suggests that for resistance to spread and pose a threat to human health, the native activity of Ddn must be at least partially retained. We tested 75 unique mutations, including all known sequence polymorphisms identified among ~15,000 sequenced M. tuberculosis genomes. Several mutations abolished pretomanid and delamanid activation in vitro, without causing complete loss of the native activity. We confirmed that a transmissible M. tuberculosis isolate from the hypervirulent Beijing family already possesses one such mutation and is resistant to pretomanid, before being exposed to the drug. Notably, delamanid was still effective against this strain, which is consistent with structural analysis that indicates delamanid and pretomanid bind to Ddn differently. We suggest that the mutations identified in this work be monitored for informed use of delamanid and pretomanid treatment and to slow the emergence of resistance.Support or Funding InformationThis work was supported by by NHMRC Project Grant APP1128929 (to C. J. J., C. G., and G. M. C.). In addition, this work was supported by an ARC DECRA Fellowship DE170100310, and NHMRC New Investigator Grant APP1139832 (to C. G.). SAB is supported by an NHMRC Career Development Fellowship GNT1090456 (to SAB). DVA and ELN acknowledge the support of the U.S. National Institutes of Health (R01‐AI111992).
Induction And Regulation of Endogenous DARC Expression in Primary Human Endothelial Cells
Authors: Khosraviani Negar , Farahani Nikki Zamani , Abramian Madlene , Wang Changsen , Lee Warren L. 
Published: April 2020

The Duffy antigen receptor for chemokines (DARC, also known as atypical chemokine receptor 1) is a blood group antigen associated with susceptibility to the parasite causing malaria. Despite homology to other chemokine receptors, DARC lacks the intracellular DRY motif present on most G‐protein‐coupled receptors that is required for signaling. Human biopsy and animal studies have indicated the presence of DARC on the endothelium of post‐capillary venules where its function and regulation are unclear. The lack of literature on endothelial DARC is attributed in part to the fact that its expression disappears in cultured endothelial cells within hours of isolation from tissue. Thus, almost all studies on endothelial DARC have required in vivo approaches. However, while the in vivo work is intriguing, the ability to study endogenous endothelial DARC in vitro will be necessary to elucidate its regulation and true physiologic function. We have discovered that incubation with human whole blood for 24 hours leads to induction of DARC on cultured primary human pulmonary microvascular endothelial cells (HPMEC). DARC induced in this manner is appropriately targeted to the cell surface, as it renders endothelial cells sensitive to an extracellular leukocidin. Induction of DARC on the endothelium was sensitive to cycloheximide, implicating de novo protein synthesis, and chromatin immunoprecipitation (ChIP) assays for RNA polymerase II also confirm transcription of the gene. While exposure to whole blood for 24 hours induced endogenous endothelial DARC expression, exposure to plasma had no effect. Transwell experiments indicated that physical contact with cellular elements in blood was necessary for induction of DARC. After induction of DARC and removal of blood, we observed rapid loss of DARC protein and mRNA within 24 hours. Our preliminary experiments suggest that endothelial DARC is rapidly degraded at least in part by matrix metalloproteinases. In conclusion, DARC expression on endothelial cells is regulated by cues from the microenvironment. DARC may play an important role in the immune system and its regulation is likely to have implications for our understanding of how cultured cells maintain or lose their in situ tissue phenotype.Support or Funding InformationThis work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) grant to W.L.L., and N.K. was supported by the Canadian Graduate Scholarship ‐ Master’s Program (CGS‐M).
The role of arginine vasopressin deficiency in the regulation of the kidney fibrosis
Authors: Quintanar-Stephano Andrés , Huerta-Carreón Erika Paulina , González-Blas Daniel , Herrera-Beiza Bernardo Miguel , Tinajero-Ruelas Manuel , Esparza-Ávila Verónica Alejandra 
Published: April 2020

It is known that arginine vasopressin (AVP) participate in the regulation of the immune responses, including the scarring. However, the effect of how AVP regulates this process is not clear. Here we describe the impact of AVP deficiency induced by neurointermediate pituitary lobectomy (NIL) or blocking the V1a‐V2 AVP receptors with conivaptan (CON) on the kidney fibrosis (KF), induced by unilateral ureteral ligature (UUL). Groups of 5 Wistar male rats were prepared: Control Intact (CI), UUL, NIL, NIL+UUL, UUL+NIL and UUL+CON. The NIL group was operated 6 weeks before sacrifice. In the NIL+UUL group NIL was performed 3 weeks before UUL and sacrificed 3 weeks after. In the UUL+CON (3mg/kg/day/SC/3 weeks before sacrifice) the UUL was done 6 weeks before sacrifice. KF was evaluated in histological slides stained with H‐E, Masson and Sirius red. Results showed that UUL induced hydronephrosis, severe kidney fibrosis and loss of histological architecture, whose severity was related to each experimental condition: In the UUL severe fibrosis occurred in the ilium, pelvis, periglomerular, intraglomerular, intraluminal tubules and interstitial kidney areas. In comparison with the CI, NIL group showed normal kidney histology, whereas that, in comparison with the UUL the NIL+UUL group developed significant less histological alterations and less kidney fibrosis. In the UUL+NIL group (NIL surgery performed 3 weeks after UUL and sacrificed 3 weeks later), although histological changes and fibrosis were apparent, these were significantly less severe as compared with the UUL group. In comparison with the NIL+UUL group, the UUL+CON animals developed less severe fibrosis and less histopathological changes. Conclusions. Results showed that kidney fibrosis may be controlled by AVP deficiency or blocking the V1a‐V2 AVP receptors (CON) indicating a major role of AVP on the fibrotic process. Results also suggests that conivaptan may be used for kidney fibrosis treatment.Support or Funding InformationUniversidad Autónoma de Aguascalientes PIFF14‐1 and CONACYT 221262. México
Defective Autophagic Degradation in Aged D2‐mdx Diaphragms
Authors: Krishna Swathy , Quindry Tiffany , Hudson Matthew B. , Quindry John C. , Selsby Joshua T. 
Published: April 2020

Duchenne muscular dystrophy (DMD) is a progressive, fatal, muscle degenerative disease caused by the absence of dystrophin, which follows an X‐linked recessive inheritance pattern. Among other cellular dysfunctions, impaired autophagy has been identified as a consequence of dystrophin deficiency in humans. Accordingly, we hypothesized that degradation of autophagosomes would be impaired in muscles of D2‐mdx mice, an emerging DMD model. To test this hypothesis, diaphragm muscles from 11 month old D2‐mdx (diseased) and DBA (healthy) mice were collected, protein extracted, and western blot analysis was performed. Data were compared with a Student’s t‐test and significance was established as p<0.05. Among the markers of upstream activation of autophagy, total AMPK was increased by 3.5‐fold, phosphorylated (p)‐AMPK was similar, and p‐AMPK/AMPK was decreased by 80% in dystrophic muscle compared to healthy muscle. Similarly, total ULK1 was increased 1.7‐fold in muscle from D2‐mdx compared to DBA, while p‐ULK1 and p‐ULK1/ULK1 were similar between groups. Total Beclin1 was increased 10‐fold and p‐Beclin1 was increased 4‐fold, resulting in a 70% reduction in p‐Beclin1/Beclin1 in dystrophic muscle compared to healthy muscle. Total mTOR, p‐mTOR, and p‐mTOR/mTOR were similar between groups. Autophagosome formation proteins ATG7, ATG16L‐1, ATG12/5 complex, LC3A/B‐I and LC3A/B‐II were increased 2–3‐fold in D2‐mdx compared to DBA, however, the ratio of LC3A/B‐II/I was similar between groups. Relative protein abundance of p62 was increased 2‐fold in D2‐mdx compared to DBA. The relative amounts of the lysosomal membrane proteins LAMP1 and LAMP2 were similar between groups, suggesting similar lysosomal content in diseased and healthy muscles. These data appear to indicate decreased autophagosome degradation in dystrophic muscle compared to healthy. Given the similar lysosome content, autophagic dysfunction in D2‐mdx mice may be due to decreased lysosome fusion or function.Support or Funding InformationSupported in part by Ryan’s Quest, Michael’s cause and Parent Project Muscular Dystrophy (01297)