bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of physical exercise in apoptosis in an experimental cerebral ischemia model
Authors: de Souza Gabriel P. N. , Porsani Lucas B. , Tirapelli Victor C. , Stevanato Ana Laura R. , Novais Paulo C. , de Assis Cirino Mucio L. , Tirapelli Daniela , Tirapelli Luis F. 
Published: May 2022

IntroductionStroke is a major public health problem, with high mortality rates and high levels of disability. Between 1990 and 2010 for example, stroke increased from the fifth to the third leading cause of disability. In addition, its incidence has increased among younger people, a situation in which there are significant health consequences and elevated social costs. There is evidence that physical exercise promotes neuroprotective effects when used as a therapeutic treatment in an experimental ischemia model. However, the mechanisms of neuroprotection are still not well understood.ObjectiveThe objective of this study was to evaluate the expression profile of the microRNAs miR‐21, miR‐16, miR‐155 and caspase‐3 and Bcl‐2 genes by real‐time PCR in brain tissue (ischemic focus) of the animals after the performance of physical training before focal cerebral ischemia.Materials and Methods48 Wistar rats were used. The animals were divided into four experimental groups: control group, ischemia group, exercise group and exercise + ischemia group. The real‐time PCR methodology was used to analyze the expression of miRNAs; miR16, miR‐21, miR‐155, caspase‐3 and Bcl‐2.Results and conclusionsIn our study, we did not observe statistically significant differences in the expression of miRNAs: miR‐16, miR‐21, miR‐155 or in the Bcl‐2 and caspase‐3 genes in brain tissue in the groups undergoing cerebral ischemia and exercise when compared to the control group.
Impaired Endothelial Function and Enhanced Contractility of Microarterioles from Persons Living with Human Immunodeficiency Virus (HIV+) is Mediated by Inflamed Perivascular Adipose Tissue
Authors: Wilcox Christopher S. , Wang Dan 
Published: May 2022

This research investigates the mechanisms that contribute to the enhanced cardiovascular disease (CVD) in HIV+ persons. It tests the hypothesis that perivascular adipose tissue (PVAT) mediates the microvascular dysfunction. Subcutaneous microarterioles were dissected from gluteal skin biopsies from 11 HIV+ and 10 matched control women aged < 50 years who were free of CVD risk factors (except increased BMI). Arterioles were mounted on isometric myographs with or without PVAT. Nitric oxide (NO) and reactive oxygen species (ROS) were measured by fluorescence microscopy. PVAT significantly (P < 0.05) enhanced endothelium‐ dependent relaxation (EDR) and NO with acetylcholine and moderated contractions with thromboxane and endothelin 1 (ET1). But these effects of PVAT were significantly (P < 0.05) diminished in HIV+ vs control subjects. Although microarterioles from HIV+ had enhanced ROS with ET1. ROS was not affected by PVAT. Incubated PVAT from HIV+ persons released significantly (P < 0.05) more leptin (47 +/‐ 8 vs 22 +/‐ 3 ng · mg‐1) and less adiponectin (3.0 +/‐ 0.4 vs 4.6 +/‐ 0.5 µg · mg‐1) but more 8‐isoprostane F2α (2.5 +/‐ 0.4 vs 1.3 +/‐ 0.3 µmol · mg‐1) and inflammatory cytokines such as TNFα (11 +/‐ 1 vs 5 +/‐ 1 pg · mg‐1).ConclusionPVAT from young HIV+ women has enhanced oxidative stress and inflammation and impaired ability to enhance microarteriolar NO and moderated contractility. Thus, PVAT and adipokines should be novel foci for therapy to reduce CVD in HIV+ persons.
Myristoylated Protein Kinase C Beta II Inhibitor Attenuates Renal Injury in Mice Subjected to Severe Bilateral Ischemia‐Reperfusion
Authors: Shah Lisa , Johnson Devani , Verwoert Alexis B. , Singh Sunit G. , Dean Tameka C. , Chen Qian , Barsotti Robert , Jiang Yanlin , George James , Agarwal Anupam , Young Lindon 
Published: May 2022

Acute kidney injury (AKI) due to ischemia‐reperfusion (I/R) insult involves oxidative stress and inflammation leading to rapid renal decline and remains a significant cause of post‐operative mortality. Myristoylated protein kinase C beta II peptide inhibitor (N‐myr‐SLNPEWNET; myr‐PKCβII‐) is known to attenuate myocardial I/R injury in ex vivo rat hearts. We hypothesized that myr‐PKCβII‐ would attenuate severe renal I/R injury that is characterized by elevated serum creatinine (Cr) and a decrease in glomerular filtration rate (GFR). We predict that treatment with myr‐PKCβII‐ will improve these indices of kidney function compared to a scrambled control peptide (N‐myr‐WNPESLNTE; myr‐PKCβII‐scram).Renal pedicles of anesthetized male C57BL/6J mice (25–30g) were clamped bilaterally for 20 min or 19 min. Five minutes before unclamping, 2.0 mg/kg (20 µM serum) myr‐PKCβII‐ or myr‐PKCβII‐scram were given i.v. into the tail vein. Cr (mg/dL) was measured at baseline, 24h, 72h, and 96h post‐injury. GFR (µl/min) was determined with fluorescein‐isothiocyanate (FITC)‐Sinistrin renal clearance. Data were evaluated by unpaired Student’s t‐test.Following 20‐min renal ischemia (Fig 1.), myr‐PKCβII‐ (n=9) significantly reduced Cr at 24h and 72h post‐injury compared to myr‐PKCβII‐scram control (n=8, p<0.05). However, there were three fatalities prior to 96h. In 19‐min ischemia, there were no fatalities up to 96h post‐injury. However, Cr levels of the myr‐PKCβII‐scram control (n=8) in 19‐min I/R were significantly lower than 20‐min I/R at all time points post‐injury (all p<0.01): 24h (0.54 ± 0.10 vs 1.59 ± 0.06 mg/dL), 72h (0.24 ± 0.06 vs 1.28 ± 0.25 mg/dL), and 96h (0.17 ± 0.03 vs 0.72 ± 0.15 mg/dL). Myr‐PKCβII‐ did not significantly reduce Cr (Fig. 1) nor improve GFR (Fig. 2) following 19‐min I/R.Results suggest that 20‐min renal ischemia was more severe, which was indicated by a 5‐fold increase of peak Cr levels at 72h post‐injury compared to 19‐min ischemia and the unanticipated fatalities of three mice. Myr‐PKCβII‐ attenuated renal injury following 20‐min renal ischemia, but not at the milder 19‐min model in which peak Cr levels were too low to detect therapeutic benefit. The large difference in injury severity between 20‐min and 19‐min renal ischemia emphasizes the temporal relationship between renal function and ischemic duration.Future studies will characterize myr‐PKCβII‐ protection against AKI in 19‐min bilateral renal ischemia based on biomarkers indicating proximal renal tubule damage (e.g. NGAL and Kim‐1). A more optimal ischemic duration between 19 min and 20 min will be investigated for future experiments.
Oxytocin, Prostaglandin F2α, and Prostaglandin E2 Induced Contractions in Isolated Uterine Smooth Muscle Strips from Non‐pregnant, Late Pregnant, and Postpartum Rats
Authors: Beard Jenifer M. , Miknich Kaitlin B. , Sarkis Mina Nader , Gusek Brikena , Jones Carleton (. , Eckman Delrae M. 
Published: May 2022

Objective/IntroductionNumerous studies have investigated uterotonic agents (e.g., oxytocin) in uterine smooth muscle (USM) from non‐pregnant (NP) and late‐pregnant (LP) women and/or animal models of pregnancy. Surprisingly, few studies have investigated USM from the post‐partum period to determine whether USM contractility returns to its pre‐pregnant state. We designed a study in rodents to investigate whether USM contractility to oxytocin (OXY), prostaglandin F2α (PGF2α), and prostaglandin E2 (PGE2) returned to pre‐pregnant values within 30 days postpartum.MethodsStudies were performed in NP (n=12), LP (21d gestation, n=4), 3 days post‐partum (PP3, n=2), and 30 days post‐partum (PP30, n=4) Sprague Dawley rats. Uterine horns were cleaned of connective tissue and cut along the longitudinal axis allowing isolation of USM (width: 2mm, length: 4±1mm) oriented in the longitudinal muscle (LM) or circular muscle (CM) direction. CM or LM strips were mounted in tissue baths containing Krebs and equilibrated @ 37°C for 60 min prior to starting one of the two following protocols.Protocol 1 identified the optimal resting tension (in grams: 0.25, 0.50, 1.0, and 1.5) to measure spontaneous contraction (SCA), K+‐induced contraction (60mM K+), and cumulative OXY‐induced contraction (10‐11 to 10‐7) in CM and LM of NP rats (N=4‐6).Protocol 2 was designed assess SCA, K+‐induced contraction, cumulative concentration‐response relationships to OXY (10‐11 to 10‐7), PGF2α (10‐8 to 10‐4), or PGE2 (10‐8 to 10‐4) in CM and LM, of NP, LP, PP3, and PP30 rats (N=2‐6).Statistical comparisons were made using either a t‐test or two‐way ANOVA, and considered statistically different at P<0.05.ResultsProtocol 1‐ LM SCA was greater than CM SCA at all resting tensions. K+‐induced constrictions in LM and CM were similar at each resting tension. OXY‐induced contraction in LM was generally greater than CM (P<0.05 at 0.25g, 0.5g, and 1.5g tension, comparable at 0.5, 1.0, and 1.5g tension).Protocol 2 ‐ SCA in NP, LM was greater than NP, CM (P<0.05). There was no difference in SCA in CM vs LM in USM from LP, PP3, and PP30 animals. K+‐induced constrictions in CM and LM were similar in USM from NP, LP, PP3 and PP30 animals. OXY‐induced contractions were greater in LM than CM for all pregnancy states (P<0.05). PGE2 contractions were greater in LM vs CM in USM from NP rats (P<0.05), but were similar in USM from LP, PP3, and PP30 animals. In contrast, PGF2α‐contractions were similar in LM and CM for all pregnancy states.Summary/ConclusionOur preliminary data suggests that uterotonic agents be assessed at either 0.5g or 1.0g resting tension. In addition, uterotonic agents exhibit significantly greater contraction in longitudinal vs circular orientation. Finally, contractility to uterotonic agents returns to pre‐pregnant values by PP30.
Complex II‐linked mitochondrial respiration is upregulated during postnatal development in high‐altitude grown mice
Authors: Arias‐Reyes Christian , Aliaga‐Raduán Fernanda , Rollano‐Peñaloza Oscar M. , Iturri Pablo , Soliz Jorge , Joseph Vincent 
Published: May 2022

Recently, we have shown that chronic normobaric hypoxia (12% O2 – 21 days) triggers mitochondrial and cell‐ metabolic plasticity in the retrosplenial cortex of male adult FVB mice but not in SD rats. In these animals we reported a transient upregulation of anaerobic metabolic pathways (glycolysis + lactate metabolism) followed by an attenuation in the mitochondrial respiration. These results pointed to an optimized use of oxygen at cellular level in an area of the brain responsible of processing visual information and spatial memory. Features of great importance in the biological fitness. In the current work we investigate how the residence in high altitude (La Paz – Bolivia, 3,600 m) affects the developmental profile of the mitochondrial respiratory efficiency in the retrosplenial cortex of mice and rats. We hypothesize that the mitochondrial plasticity observed in adult mice will have a process of maturation during postnatal development. This response shall be absent in rats.To do so, we measured the mitochondrial oxygen consumption rate (OCR) in saponin‐permeabilized brain samples from FVB mice and SD rats born and grown in La Paz. The animals were sacrificed at postnatal ages p7, p14, p21, and adulthood (P90), and the OCR linked to the use of NADH (N pathway), FADH2 (S pathway), or both (NS pathway) was quantified by means of high‐resolution respirometry (OROBOROS).Our results show a pattern of maturation (increase) of the mitochondrial respiration in the retrosplenial cortex along with the postnatal development (21 days+) of mice and rats. However, an upregulation of the participation of the S pathway (complex II‐linked) in the mitochondrial respiration was observed during the first three weeks of age only in mice. This observation supports previous works suggesting a key role of the complex II and succinate (substrate of complex II) in the successful cellular and mitochondrial acclimatization to hypoxia. These findings contribute to further establish FVB mice and SD rats as a model to study divergent acclimatization to hypoxia.
Comparative Studies on the Interaction of Heparins from Various Origins with Heparin Cofactor II and Antithrombin
Authors: Baig Nausheen , Kouta Ahmed , Jaradeh Mark , Hoppensteadt Debra , Jeske Walter , Fareed Jawed 
Published: May 2022

IntroductionUnfractionated heparins (UFH) of mucosal origin are currently obtained from bovine, ovine, and porcine sources. In the USP potency assays, bovine mucosal heparin (BMH) exhibit much lower activities (140 U/mg) in comparison to porcine mucosal heparin (PMH; 195 U/mg) and ovine mucosal heparin (OMH; 200 U/mg). Besides molecular and structural differences, these heparins have differential interactions with serpins such as antithrombin (AT) and heparin cofactor II (HCII). The purpose of this study is to compare the inhibitory profiles of various heparins in systems enriched with AT and HCII.Materials andMethodsThe active pharmaceutical ingredients (API) of BMH, OMH, and PMH were obtained from Kin Master (Brazil), Ronssi (China), and Medefil (USA). Bovine (B.LMWH), ovine (O.LMWH), and porcine (P.LMWH) derived low‐molecular‐weight heparins (LMWH, enoxaparin) were obtained from Ronssi (China). Purified human AT, HCII, and thrombin (IIa) were obtained from Enzyme Research (USA). All heparins (UFH’s and LMWH’s) were supplemented to AT and HCII enriched buffer systems at various gravimetric and potency equated concentrations. The relative inhibition of IIa was measured in terms of percent inhibition using an amidolytic method employing IIa specific substrates. Percent inhibition was calculated for each concentration in both systems for each of the three heparins. Inhibitory concentrations required to inhibit 50% of thrombin (IC‐50) was calculated for each UFH and LMWH in terms of µg/mL and U/mL.ResultsIn the AT supplemented system using gravimetric concentrations of various UFH’s, PMH and OMH showed comparable values, whereas BMH exhibited much higher IC‐50’s. However, the LMWH’s of various origins showed comparable IC‐50 values. In this same system, the USP potency adjusted heparins exhibited comparable results for all UFH’s (Figure 1). In the HCII supplemented system, UFH’s of various origins exhibited similar IC‐50 values in both gravimetric and USP potency adjusted studies. Similarly, the LMWH’s when compared in gravimetric amounts demonstrated similar IC‐50 values (Figure 2). The relative IC‐50 values of the LMWH’s in both the AT and HCII enriched systems were higher than the UFH’s.ConclusionThese results show that potency adjusted UFH’s exhibit comparable inhibition of IIa in AT and HCII enriched systems. The differing BMH results observed in these two systems at gravimetric concentrations may partly be due to differences in charge density and AT‐binding consensus sequences. The depolymerized enoxaparin of different origins did not reveal any significant differences in the IC‐50 values. This may be due to the chemical modifications that occur during the manufacturing of these agents. Future studies may be warranted to further investigate these cofactors and their impacts on the function of various heparins.
Role of HCN Currents in Epileptiform Activity in Subicular Neurons
Authors: Alfred Monica , Sikdar Sujit K. 
Published: May 2022

Subicular neurons play a critical role in Temporal Lobe Epilepsy. While studies have shed light on how synaptic conductances contribute to epileptiform activity in these neurons, it is still unclear how intrinsic conductances influence epileptic discharges. HCN channels play crucial role in pathophysiology by modulating the electrophysiological properties of neurons. To investigate the ability of intrinsic properties in a subicular neuron to generate epileptiform activity, we studied the effects of Ih (HCN) currents in 4‐Aminopyridine magnesium‐free epileptic model in various classes of subicular neurons. To study the modulation of epileptiform activity due to Ih in these neurons, we modeled subicular HCN currents in dynamic clamp that mimicked the effects of blocker and overexpression. We observed similar changes in input resistances with the subtraction and addition of currents in burst firing, regular firing and interneurons. However, the firing rate characteristics during epileptiform activity with the modulation of HCN channels in burst firing and regular firing differed from those observed in interneurons. The results indicated that the burster cells majorly contribute to the epileptic firing characteristics due to HCN in subiculum.During the epileptiform activity, these bursters showed progressive loss of homeostatic compensation characterized by decrease in sag ratio and and loss in theta frequency. The loss of homeostatic compensation incurred was found to be irreversible. These irreversible changes are also characterized by altered HCN channel kinetics. To study how these epilepsy‐induced alterations govern neuronal excitability, we studied the electrophysiological profiles of subicular neurons with altered HCN current kinetics introduced through dynamic clamp in the presence of ZD7288. These irreversible changes are also characterized by altered HCN channel kinetics. To study how these epilepsy‐induced alterations govern neuronal excitability, we studied the electrophysiological profiles of subicular neurons with altered HCN current kinetics introduced through dynamic clamp in the presence of ZD7288. The results showed that the theta selectivity and sag profiles were modulated and post‐inhibitory rebound firing were evoked making the cell hyperexcitable. It is known that the stable neuronal network is homeostatically regulated by intrinsic excitability and synaptic currents. Studies are being conducted to understand the interaction between Ih and synaptic currents before and during the epileptiform activity in neurons with post‐epileptic induced hyperexcitability.
A Novel Animal Model in Diabetes: Regeneration of β cells in the Axolotl Salamander?
Authors: Sørensen Pernille L. , Dittrich Anita L. , Lauridsen Henrik L. 
Published: May 2022

Diabetes is an ever‐growing health issue affecting an estimate of 463 million people worldwide. Type 1 diabetes is characterized by hyperglycemia and loss of pancreatic β cell mass. Currently, there is no curative treatment of β cell loss. Humans have a poor natural ability to regenerate β cells, empathizing the importance of conducting research in regenerative medicine. However, this field of study is limited by the animal models available due to their inadequate intrinsic ability to regenerate, size and/or remoteness from humans. As the axolotl salamander (Ambystoma mexicanum) has an intrinsic ability to regenerate limbs and organs throughout life, it is an advantageous animal model for studying the physiological and molecular mechanisms of regeneration. Compared to zebrafish, a well‐established regenerative animal model of diabetes, the size of the axolotl (up to 150 g) is fit for pre‐clinical imaging systems and serial blood samples throughout an experiment without causing any detrimental effects.We hypothesize that the axolotl has the ability to regenerate β cells, giving it the potential of becoming a new regenerative animal model of diabetes. To generate a diabetes‐like axolotl, streptozotocin, a cytotoxic glucose analogue targeting β cells specifically, was injected intraperitoneally. Initially, a protocol inspired by studies of zebrafish were used, in which 0.35 mg/g body mass was given at day 0, 1, 2, 11, and 18 to group 1 (n=12). However, this dosage caused high mortality, and the experiment was terminated prematurely. Therefore, three new dosage regimes inspired by rodent studies were investigated. For group 2 (n=3), animals were treated with 0.05 mg/g body mass at 5 consecutive days, group 3 (n=3) was given 0.05 mg/g body mass at day 0, 2, 4, 12, and 19, and group 4 (n=3) was given a single dose of 0.2 mg/g body mass at day 0. Disease development was detected by glucose tolerance tests and will further be investigated with immunofluorescence. Potential off target effects of streptozotocin will be characterized by examining changes in red blood cell morphology and the histology of liver and kidney.We found that the treatment given to group 2 and 3 resulted in diabetes‐like symptoms when compared to a control group. Group 3 resulted in low‐grade hyperglycemia, whereas the 5 consecutive injections given to group 2 caused moderate hyperglycemia.Our results demonstrate that the axolotl is able to develop diabetes‐like symptoms by streptozotocin treatment. We anticipate that further adjustments to the dosage regime given to group 2 will result in severe hyperglycemia and thus model a diabetic axolotl, and that this animal model will be able to regenerate the lost β cells. Thus, this animal model will be useful for studying the cellular source of the regenerated cells and the molecular mechanisms of regeneration.
Evidence of Mitochondrial Impairment in a Mouse Model of Down Syndrome
Authors: Anyaoku Cynthia , DeRuisseau Lara R. , Brandauer Josef 
Published: May 2022

IntroductionDown Syndrome (DS) is typically the result of triplication of the 21st chromosome. DS causes widespread developmental and physical changes to the body. One commonly observed physical change of DS is muscle weakness, which can contribute to difficulty in executing activities of daily living.Nicotinamide adenine dinucleotide (NAD) is an important determinant of skeletal muscle function and mitochondrial activity. Currently, it is unknown whether muscle weakness in those with DS is at least partially related to an imbalance of NAD or a lack of mitochondrial NAD usage. Nicotinamide phosphoribosyl transferase (Nampt) catalyzes the rate‐limiting step in the mammalian NAD recycling pathway, while SIRT3 is an NAD‐dependent protein deacetylase which regulates mitochondrial content and activity. We hypothesized the expression of these proteins would be decreased in Ts65Dn animals, an established mouse model of DS, relative to wild‐type (WT) animals.MethodsDiaphragm and left ventricle samples from 12‐ or 18‐month‐old male Ts65Dn mice and WT animals were pulverized and homogenized in ice‐cold lysis buffer. Total lysate protein concentration was determined by Bradford assay. Samples were resolved in SDS gels, transferred to nitrocellulose membranes, and blotted for Nampt and SIRT3. Lysates were also separately analyzed for citrate synthase activity.ResultsBoth Nampt (p = 0.02) and SIRT3 (p = 0.002) expression levels were significantly higher in WT than Ts65Dn ventricles at 12 months. In addition, SIRT3 levels were higher in diaphragm of 12‐month‐old WT animals (p = 0.02). Citrate synthase levels were similar in all tissues.ConclusionOur findings of reduced Nampt protein suggest that reduced NAD recycling takes place in DS muscle tissue despite similar observed mitochondrial (citrate synthase) activity. These results suggest a role of diminished peripheral mitochondrial function and ATP synthesis in Down Syndrome muscle.