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Find video protocols related to scientific articles indexed in Pubmed.
Muscle activity during running with different body-weight-support mechanisms: aquatic environment versus body-weight-support treadmill.
J Sport Rehabil
PUBLISHED: 10-30-2014
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Body-weight (BW) support during running can be accomplished using deep-water running (DWR; 100% BW support) and a lower-body positive-pressure (LBPP) treadmill.
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Lower Extremity Muscle Activity During a Women's Overhand Lacrosse Shot.
J Hum Kinet
PUBLISHED: 07-08-2014
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The purpose of this study was to describe lower extremity muscle activity during the lacrosse shot. Participants (n=5 females, age 22±2 years, body height 162.6±15.2 cm, body mass 63.7±23.6 kg) were free from injury and had at least one year of lacrosse experience. The lead leg was instrumented with electromyography (EMG) leads to measure muscle activity of the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (GA). Participants completed five trials of a warm-up speed shot (Slow) and a game speed shot (Fast). Video analysis was used to identify the discrete events defining specific movement phases. Full-wave rectified data were averaged per muscle per phase (Crank Back Minor, Crank Back Major, Stick Acceleration, Stick Deceleration). Average EMG per muscle was analyzed using a 4 (Phase) × 2 (Speed) ANOVA. BF was greater during Fast vs. Slow for all phases (p<0.05), while TA was not influenced by either Phase or Speed (p>0.05). RF and GA were each influenced by the interaction of Phase and Speed (p<0.05) with GA being greater during Fast vs. Slow shots during all phases and RF greater during Crank Back Minor and Major as well as Stick Deceleration (p<0.05) but only tended to be greater during Stick Acceleration (p=0.076) for Fast vs. Slow. The greater muscle activity (BF, RF, GA) during Fast vs. Slow shots may have been related to a faster approach speed and/or need to create a stiff lower extremity to allow for faster upper extremity movements.
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Automated synthesis and dosimetry of 6-deoxy-6-[(18)F]fluoro-D-fructose (6-[(18)F]FDF): a radiotracer for imaging of GLUT5 in breast cancer.
Am J Nucl Med Mol Imaging
PUBLISHED: 01-01-2014
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6-Deoxy-6-[(18)F]fluoro-D-fructose (6-[(18)F]FDF) is a promising PET radiotracer for imaging GLUT5 in breast cancer. The present work describes GMP synthesis of 6-[(18)F]FDF in an automated synthesis unit (ASU) and dosimetry calculations to determine radiation doses in humans. GMP synthesis and dosimetry calculations are important prerequisites for first-in-human clinical studies of 6-[(18)F]FDF. The radiochemical synthesis of 6-[(18)F]FDF was optimized and adapted to an automated synthesis process using a Tracerlab FXFN ASU (GE Healthcare). Starting from 30 GBq of cyclotron-produced n.c.a. [(18)F]fluoride, 2.9 ± 0.1 GBq of 6-[(18)F]FDF could be prepared within 50 min including HPLC purification resulting in an overall decay-corrected radiochemical yield of 14 ± 3% (n = 11). Radiochemical purity exceeded 95%, and the specific activity was greater than 5.1 GBq/?mol. Sprague-Dawley rats were used for biodistribution experiments, and dynamic and static small animal PET experiments. Biodistribution studies served as basis for allometric extrapolation to the standard man anatomic model and normal organ-absorbed dose calculations using OLINDA/EXM software. The calculated human effective dose for 6-[(18)F]FDF was 0.0089 mSv/MBq. Highest organ doses with a dose equivalent of 0.0315 mSv/MBq in a humans were found in bone. Injection of 370 MBq (10 mCi) of 6-[(18)F]FDF results in an effective whole body radiation dose of 3.3 mSv in humans, a value comparable to that of other (18)F-labeled PET radiopharmaceuticals. The optimized automated synthesis under GMP conditions, the good radiochemical yield and the favorable human radiation dosimetry estimates support application of 6-[(18)F]FDF in clinical trials for molecular imaging of GLUT5 in breast cancer patients.
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A computationally designed DNA aptamer template with specific binding to phosphatidylserine.
Nucleic Acid Ther
PUBLISHED: 11-26-2013
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The phospholipid phosphatidylserine (PS) is an early marker exploited for detecting apoptosis (PS externalization in the cell membrane bilayer) and one factor that is associated with increased amyloid plaque deposition in transmissible spongiform encephalopathies (TSEs). PS can therefore be considered as a promising target for diagnosis or treatment of diseases. Aptamers (short nucleic acid sequences) are a particularly attractive class of materials among those currently considered for targeting PS. Here we applied an entropy based seed-and-grow strategy to design a DNA aptamer template to bind specifically to PS. The binding properties of designed aptamers were investigated computationally and experimentally. The studies identify the sequence, 5-AAAGAC-3, as the preferred template for further modifications and studies toward its practical implementations.
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Muscle Activity During Running With Different Body Weight Support Mechanisms: Aquatic Environment Versus Body Weight Support Treadmill.
J Sport Rehabil
PUBLISHED: 08-06-2013
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Background: Body weight (BW) support during running can be accomplished using deep water running (DWR) (100% BW support) and Lower Body Positive Pressure (LBPP) treadmill. Purpose: The purpose of this study was to compare lower extremity muscle activity during DWR and running on a LBPP treadmill at matched stride frequency. Methods: Eight subjects (40(6.5) yrs; 173(7.2) cm; 66.9(11.7) kg) completed four running conditions all at a preferred stride frequency which was determined while running with no support. Two conditions were running on the LBPP treadmill at 60% and 80% of body weight and the remaining two conditions were different DWR styles: High knee, Cross-country. Average (AVG) and root mean square (RMS) electromyography (rectus femoris, biceps femoris, gastrocnemius, tibalis anterior) were each compared among conditions (repeated measures analysis of variance). Results: Results for AVG and RMS variables were identical for statistical test for each muscle. Rectus femoris electromyography during DWR-High Knee was lower than that of DWR-Cross Country (p<.05) but not different than either 60%BW or 80%BW (p>.05). Biceps femoris electromyography was less during DWR-High Knee vs. DWR-Cross Country (p<.05) but greater during DWR-High Knee vs. either BW60% or BW80% (p<0.05). Neither gastrocnemius nor tibialis anterior electromyography were different between conditions (p>.05). Conclusion: The mechanism of BW support nor style of DWR influenced gastrocnemius or tibialis anterior muscle activity during running at the same stride frequency. However, rectus femoris and biceps femoris muscle activity were influenced not only by the mechanism of BW support but also the style of DWR.
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How does juxtaluminal calcium affect critical mechanical conditions in carotid atherosclerotic plaque? an exploratory study.
IEEE Trans Biomed Eng
PUBLISHED: 07-31-2013
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Background: The impact of calcification on the carotid atherosclerotic plaque vulnerability remains controversial and unclear. This study assesses the critical mechanical conditions induced by the calcium at the lumen surface i.e. juxtaluminal calcification (JLCa), within human carotid atherosclerotic plaque. Methods: Eleven patients with evidence of JLCa were included for the analysis. The plaque geometry was reconstructed based on CT and MR images and 3D fluid-structure interaction simulation was used for mechanical analysis. Results: Presence of JLCa increased local stresses compared to when calcification was artificially covered with a 0.2mm-thickness FC (107.87kPa [76.99, 129.14] vs. 63.17 kPa [34.55, 75.13]; Median, [inter quartile range]; p<0.0001]. Stretch ratio decreased from 1.18 [1.07, 1.27] to 1.13 [1.10, 1.18] (p=0.03). Conclusion: The presence of JLCa significantly elevates local stress and stretch level. Further exploration of this plaque feature is warranted as a possible risk factor causing plaque vulnerability.
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Mitochondrial bioenergetics and therapeutic intervention in cardiovascular disease.
Pharmacol. Ther.
PUBLISHED: 07-16-2013
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Cardiovascular disease remains the commonest form of mortality and morbidity in the Western World. It accounts for more deaths than the combined incidence of all cancers. There remains an urgency to identify and translate therapies to reduce the effects of this disease and its associated co-morbidities. Atherosclerotic disease accounts for over two thirds of all cardiovascular related deaths. Arterial vessel wall plaques rupture and cause death due to loss of integrity of the overlaying vascular smooth muscle cell (VSMC) cap. Although plaques contain a heterogeneous pool of different cell types, it is the VSMCs that by their nature are responsible for rupture. VSMC are the primary source of extracellular matrix and collagen and it has been suggested that loss of viability and vitality of these cells contributes to plaque vulnerability and rupture. While DNA damage has long been associated with atherosclerotic plaques only relatively recently has the contribution of mitochondrial DNA damage been suggested to play a role. The mitochondrial respiratory chain is a source of ATP that the cell requires for all its energetic functions but is also a source of free radicals that produce reactive species (RS). While these RS exacerbate DNA damage and attack lipids and proteins, it is the loss of ATP that may ultimately be more detrimental. Therapeutic intervention for mitochondria dysfunction is one route on alleviating this burden. Finding alternative sources of ATP synthesis by energetic reconfiguration may also provide a vital link in delaying the kinetics of plaque rupture.
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Mitochondrial DNA damage can promote atherosclerosis independently of reactive oxygen species through effects on smooth muscle cells and monocytes and correlates with higher-risk plaques in humans.
Circulation
PUBLISHED: 07-10-2013
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Mitochondrial DNA (mtDNA) damage occurs in both circulating cells and the vessel wall in human atherosclerosis. However, it is unclear whether mtDNA damage directly promotes atherogenesis or is a consequence of tissue damage, which cell types are involved, and whether its effects are mediated only through reactive oxygen species.
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Muscle activity while running at 20%-50% of normal body weight.
Res Sports Med
PUBLISHED: 06-20-2013
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Little information exists on how body weight (BW) support influences running biomechanics. The study aim was to determine how reducing BW by 50%-80% influences muscle activity while running at different speeds. Subjects (n?=?7) ran at 100%, 115%, 125% of preferred speed at 100%, 50%, 40%, 30%, 20% of BW per speed. Average (AVG) electromyography of the rectified signal was compared (within subject design; 3-speeds?×?5-BW, repeated measures ANOVAs; biceps femoris [BF], rectus femoris [RF], tibialis anterior [TA], gastrocnemius [GA]). RF, BF, and GA AVG were not influenced by BW-speed interaction (p > .05) and increased across speeds (p < .05). RF and GA AVG signal was reduced as BW was reduced (p < .05), but BF only tended to be different (p = .08). TA was influenced by BW-speed interaction (p < .05) with EMG decreasing across BW (p < .05) while increasing across speeds except at 100% BW. Overall, muscle activity increased with speed and decreased by BW reductions.
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Glia to axon RNA transfer.
Dev Neurobiol
PUBLISHED: 05-14-2013
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The existence of RNA in axons has been a matter of dispute for decades. Evidence for RNA and ribosomes has now accumulated to a point at which it is difficult to question, much of the disputes turned to the origin of these axonal RNAs. In this review, we focus on studies addressing the origin of axonal RNAs and ribosomes. The neuronal soma as the source of most axonal RNAs has been demonstrated and is indisputable. However, the surrounding glial cells may be a supplemental source of axonal RNAs, a matter scarcely investigated in the literature. Here, we review the few papers that have demonstrated that glial-to-axon RNA transfer is not only feasible, but likely. We describe this process in both invertebrate axons and vertebrate axons. Schwann cell to axon ribosomes transfer was conclusively demonstrated (Court et al. [2008]: J. Neurosci 28:11024-11029; Court et al. [2011]: Glia 59:1529-1539). However, mRNA transfer still remains to be demonstrated in a conclusive way. The intercellular transport of mRNA has interesting implications, particularly with respect to the integration of glial and axonal function. This evolving field is likely to impact our understanding of the cell biology of the axon in both normal and pathological conditions. Most importantly, if the synthesis of proteins in the axon can be controlled by interacting glia, the possibilities for clinical interventions in injury and neurodegeneration are greatly increased. © 2013 Wiley Periodicals, Inc. Develop Neurobiol, 2013.
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[131I]IAZA as a molecular radiotherapeutic (MRT) drug: wash-out with cold IAZA accelerates clearance in a murine tumor model.
Curr Radiopharm
PUBLISHED: 04-05-2013
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Based on animal model studies, [131I]IAZA may be useful as an adjunct radiotherapeutic (MRT) drug for the treatment of tumor hypoxia. However, radioactivity in the blood of patients and healthy volunteers dosed with [123I]IAZA has a protracted terminal elimination phase in which clearance is influenced by free [123I]IAZA and possibly by unidentified metabolites. The current work reports that about 40% of the radioactivity in human serum is associated with the serum protein fraction, and that the free:bound ratio is constant at about 60:40 for at least the first 135 min after injection, as determined by radio-HPLC analyses. In order to modulate the clearance of bound and free radioactive IAZA, nonradioactive (cold) IAZA was administered i.v. 1 h following injection of high specific activity [125I][IAZA in the Balb/C EMT-6 murine tumor model. This wash out procedure reduced the concentrations of radioactivity by at least 40% in all tissues, with greatest effect in kidney and liver, and least in tumor. As a result, the tumor:blood ratio increased from 5.8 to 8.5 at 4 h post-injection. This effect would be advantageous for the use of [131I]IAZA as an MRT drug. Optimization of intervals between radioactive and wash out dose, and confirmation of the self-irradiation dose to all tissues, remain to be undertaken before [131I]IAZA can be tested as a low-dose-rate MRT supplement to external beam x-ray radiotherapy.
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Myosin-Va-dependent cell-to-cell transfer of RNA from Schwann cells to axons.
PLoS ONE
PUBLISHED: 01-01-2013
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To better understand the role of protein synthesis in axons, we have identified the source of a portion of axonal RNA. We show that proximal segments of transected sciatic nerves accumulate newly-synthesized RNA in axons. This RNA is synthesized in Schwann cells because the RNA was labeled in the complete absence of neuronal cell bodies both in vitro and in vivo. We also demonstrate that the transfer is prevented by disruption of actin and that it fails to occur in the absence of myosin-Va. Our results demonstrate cell-to-cell transfer of RNA and identify part of the mechanism required for transfer. The induction of cell-to-cell RNA transfer by injury suggests that interventions following injury or degeneration, particularly gene therapy, may be accomplished by applying them to nearby glial cells (or implanted stem cells) at the site of injury to promote regeneration.
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Entropic fragment-based approach to aptamer design.
Chem Biol Drug Des
PUBLISHED: 05-25-2011
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Aptamers are short RNA/DNA sequences that are identified through the process of systematic evolution of ligands by exponential enrichment and that bind to diverse biomolecular targets. Aptamers have strong and specific binding through molecular recognition and are promising tools in studying molecular biology. They are recognized as having potential therapeutic and diagnostic clinical applications. The success of the systematic evolution of ligands by exponential enrichment process requires that the RNA/DNA pools used in the process have a sufficient level of sequence diversity and structural complexity. While the systematic evolution of ligands by exponential enrichment technology is well developed, it remains a challenge in the efficient identification of correct aptamers. In this article, we propose a novel information-driven approach to a theoretical design of aptamer templates based solely on the knowledge regarding the biomolecular target structures. We have investigated both theoretically and experimentally the applicability of the proposed approach by considering two specific targets: the serum protein thrombin and the cell membrane phospholipid phosphatidylserine. Both of these case studies support our method and indicate a promising advancement in theoretical aptamer design. In unfavorable cases where the designed sequences show weak binding affinity, these template sequences can be still modified to enhance their affinities without going through the systematic evolution of ligands by exponential enrichment process.
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Effects of overweight and obesity on walking characteristics in adolescents.
Hum Mov Sci
PUBLISHED: 04-13-2011
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Child and adolescent obesity is growing at a staggering rate. Associated potential health risks have been acknowledged in the adult population, and similar concerns have been raised for children and adolescents. However, distinguishing locomotor characteristics related to obesity have yet to be clearly identified for adolescents. The aims of the study were to examine the effects of walking velocity and gender on spatio-temporal characteristics of gait between normal weight (NW) and overweight and obese (OWO) adolescents. In addition, we sought to identify characteristics of gait that are related to body mass index percentile (BMI%). Adolescent students in grades 7-10 (N=111) from a charter school participated in the study. All participants walked at two speeds (preferred, fast) over an instrumented walkway (120 Hz). Spatio-temporal characteristics of gait were extracted from four walkway passes and evaluated. Results identified significant (p<.05) differences in velocity, percent double support, percent swing phase, and stance width between groups. Only stance width was different (p<.05) between genders. Models to predict BMI% from kinematic walking parameters were of moderate strength (averaging 43.5% explained variance) and were generally stronger for females versus males. Percent double support was the primary predictor variable of BMI% across speed and gender. It is suggested that OWO adolescents may be challenged with control of movement of the center of mass during the support phase of walking.
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Myosin5a tail associates directly with Rab3A-containing compartments in neurons.
J. Biol. Chem.
PUBLISHED: 02-23-2011
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Myosin-Va (Myo5a) is a motor protein associated with synaptic vesicles (SVs) but the mechanism by which it interacts has not yet been identified. A potential class of binding partners are Rab GTPases and Rab3A is known to associate with SVs and is involved in SV trafficking. We performed experiments to determine whether Rab3A interacts with Myo5a and whether it is required for transport of neuronal vesicles. In vitro motility assays performed with axoplasm from the squid giant axon showed a requirement for a Rab GTPase in Myo5a-dependent vesicle transport. Furthermore, mouse recombinant Myo5a tail revealed that it associated with Rab3A in rat brain synaptosomal preparations in vitro and the association was confirmed by immunofluorescence imaging of primary neurons isolated from the frontal cortex of mouse brains. Synaptosomal Rab3A was retained on recombinant GST-tagged Myo5a tail affinity columns in a GTP-dependent manner. Finally, the direct interaction of Myo5a and Rab3A was determined by sedimentation velocity analytical ultracentrifugation using recombinant mouse Myo5a tail and human Rab3A. When both proteins were incubated in the presence of 1 mm GTP?S, Myo5a tail and Rab3A formed a complex and a direct interaction was observed. Further analysis revealed that GTP-bound Rab3A interacts with both the monomeric and dimeric species of the Myo5a tail. However, the interaction between Myo5a tail and nucleotide-free Rab3A did not occur. Thus, our results show that Myo5a and Rab3A are direct binding partners and interact on SVs and that the Myo5a/Rab3A complex is involved in transport of neuronal vesicles.
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The mitochondria-targeted antioxidant MitoQ decreases features of the metabolic syndrome in ATM+/-/ApoE-/- mice.
Free Radic. Biol. Med.
PUBLISHED: 02-18-2011
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A number of recent studies suggest that mitochondrial oxidative damage may be associated with atherosclerosis and the metabolic syndrome. However, much of the evidence linking mitochondrial oxidative damage and excess reactive oxygen species (ROS) with these pathologies is circumstantial. Consequently the importance of mitochondrial ROS in the etiology of these disorders is unclear. Furthermore, the potential of decreasing mitochondrial ROS as a therapy for these indications is not known. We assessed the impact of decreasing mitochondrial oxidative damage and ROS with the mitochondria-targeted antioxidant MitoQ in models of atherosclerosis and the metabolic syndrome (fat-fed ApoE(-/-) mice and ATM(+/-)/ApoE(-/-) mice, which are also haploinsufficient for the protein kinase, ataxia telangiectasia mutated (ATM). MitoQ administered orally for 14weeks prevented the increased adiposity, hypercholesterolemia, and hypertriglyceridemia associated with the metabolic syndrome. MitoQ also corrected hyperglycemia and hepatic steatosis, induced changes in multiple metabolically relevant lipid species, and decreased DNA oxidative damage (8-oxo-G) in multiple organs. Although MitoQ did not affect overall atherosclerotic plaque area in fat-fed ATM(+/+)/ApoE(-/-) and ATM(+/-)/ApoE(-/-) mice, MitoQ reduced the macrophage content and cell proliferation within plaques and 8-oxo-G. MitoQ also significantly reduced mtDNA oxidative damage in the liver. Our data suggest that MitoQ inhibits the development of multiple features of the metabolic syndrome in these mice by affecting redox signaling pathways that depend on mitochondrial ROS such as hydrogen peroxide. These findings strengthen the growing view that elevated mitochondrial ROS contributes to the etiology of the metabolic syndrome and suggest a potential therapeutic role for mitochondria-targeted antioxidants.
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Radiolabeling of phosphatidylserine-binding peptides with prosthetic groups N-[6-(4-[18F]fluorobenzylidene)aminooxyhexyl]maleimide ([18F]FBAM) and N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB).
Appl Radiat Isot
PUBLISHED: 02-07-2011
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The widely used (18)F-prosthetic group N-succinimidyl-4-[(18)F]fluorobenzoate ([(18)F]SFB) and the recently developed N-[6-(4-[(18)F]fluorobenzylidene)aminooxyhexyl]maleimide ([(18)F]FBAM) were investigated for radiolabeling of two representative phosphatidylserine-binding peptides. The prosthetic groups were compared with respect to required reactions conditions for optimum labeling, radiolabeling yield and chemoselectivity. The N-terminus labeled product produced by reaction of [(18)F]SFB with binding peptide LIKKPF was produced in 18% radiochemical yield while no N-terminus labeled product could be isolated following [(18)F]SFB reaction with PDGLSR. When the peptides were modified by addition of a cysteine residue at the N-terminus they provided almost quantitative radiochemical yields with [(18)F]FBAM. Results indicate that for the peptides in this study, [(18)F]FBAM is a more useful prosthetic group compared to [(18)F]SFB due to its excellent chemoselectivity and high radiochemical yield.
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Radiopharmacological evaluation of 6-deoxy-6-[18F]fluoro-D-fructose as a radiotracer for PET imaging of GLUT5 in breast cancer.
Nucl. Med. Biol.
PUBLISHED: 02-04-2011
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Several clinical studies have shown low or no expression of GLUT1 in breast cancer patients, which may account for the low clinical specificity and sensitivity of 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) used in positron emission tomography (PET). Therefore, it has been proposed that other tumor characteristics such as the high expression of GLUT2 and GLUT5 in many breast tumors could be used to develop alternative strategies to detect breast cancer. Here we have studied the in vitro and in vivo radiopharmacological profile of 6-deoxy-6-[(18)F]fluoro-D-fructose (6-[(18)F]FDF) as a potential PET radiotracer to image GLUT5 expression in breast cancers.
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In vitro characterization of two novel biodegradable vectors for the delivery of radiolabeled antisense oligonucleotides.
Cancer Biother. Radiopharm.
PUBLISHED: 11-03-2010
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The development of antisense oligonucleotides suitable for tumor targeting applications is hindered by low stability and bioavailability of oligonucleotides in vivo and by the absence of efficient and safe vectors for oligonucleotide delivery. Stabilization in vivo has been achieved through chemical modification of oligonucleotides by various means, but effective approaches to enhance their intracellular delivery are lacking. This study reports on the characterization in vitro of a fully phosphorothioated 20-mer oligonucleotide, complementary to p21 mRNA, radiolabeled with fluorine-18 using a thiol reactive prosthetic group. The potential of two novel synthetic block copolymers containing grafted polyamines on their hydrophobic blocks for vector-assisted cell delivery was studied in vitro. Extensive cellular uptake studies were performed in human colon carcinoma cell lines with enhanced or deficient p21 expression to evaluate and compare the uptake mechanism of naked and vectorized radiolabeled formulations. Uptake studies with the two novel biodegradable vectors showed a moderate increase in cell uptake of the radiofluorinated antisense oligonucleotide. The two vectors show, however, promising advantages over conventional lipidic vectors regarding their biocompatibility and subcellular distribution.
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Radiotracers for noninvasive molecular imaging of tumor cell death.
Cancer Biother. Radiopharm.
PUBLISHED: 11-03-2010
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The need to monitor cancer therapy-induced cellular and tissue changes using noninvasive imaging techniques continues to stimulate both basic and clinical research. Monitoring changes in cellular proliferative capacity that occur after treatment with radiation and/or chemotherapy has the potential to provide longitudinal information on the cellular dynamics of tumors before, during, and after therapeutic intervention. Cells can lose their reproductive potential through one of several mechanisms, including apoptosis and autophagy (which are forms of programmed cell death), premature senescence, or necrosis. When a tumor responds to therapy, current imaging methods do not provide information about the exact mechanism of cell death executed. We are now beginning to develop the molecular imaging tools that will enable us to noninvasively image cell death mechanisms both in experimental models and in the clinical cancer environment. Studies with these imaging tools will contribute to a better understanding of therapeutic responses and assist in the design and evaluation of more effective treatments. This review examines the state-of-the-art in the use of (radio)tracers for the purpose of imaging mechanisms of tumor cell inactivation (cell death) in animal models and in clinical trials.
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Synthesis and application of 4-[(18)F]fluorobenzylamine: A versatile building block for the preparation of PET radiotracers.
Org. Biomol. Chem.
PUBLISHED: 08-25-2010
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A novel synthesis of 4-[(18)F]fluorobenzylamine ([(18)F]FBA) by means of transition metal-assisted sodium borohydride reduction of 4-[(18)F]fluorobenzonitrile ([(18)F]FBN) is described. This approach could successfully be extended to borohydride exchange resin (BER) enabling a viable option for use in automated syntheses. [(18)F]FBA was used for the synthesis of 4-[(18)F]fluorobenzylamine-based thiol group-reactive prosthetic groups 4-[(18)F]fluorobenzyl-2-bromoacetamide ([(18)F]FBBA) and 4-[(18)F]fluorobenzylamidopropionyl maleimide ([(18)F]FBAPM). [(18)F]FBBA and [(18)F]FBAPM were obtained in radiochemical yields of 75% and 55%, respectively. Feasibility of using [(18)F]FBAPM as novel prosthetic group for peptide and protein labelling was demonstrated with cysteine-containing tripeptide glutathione (GSH). [(18)F]FBBA was used for labelling of a fully phosphorothioated 20mer oligodesoxynucleotide (ODN).
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Biodistribution and uptake of 3-deoxy-3-fluorothymidine in ENT1-knockout mice and in an ENT1-knockdown tumor model.
J. Nucl. Med.
PUBLISHED: 08-18-2010
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(18)F-3-Deoxy-3-fluorothymidine ((18)F-FLT) is a PET tracer that accumulates in proliferating tissues. The current study was undertaken to determine whether equilibrative nucleoside transporter 1 (ENT1) is important for (18)F-FLT uptake in normal tissues and tumors.
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DNA damage links mitochondrial dysfunction to atherosclerosis and the metabolic syndrome.
Circ. Res.
PUBLISHED: 08-12-2010
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DNA damage is present in both genomic and mitochondrial DNA in atherosclerosis. However, whether DNA damage itself promotes atherosclerosis, or is simply a byproduct of the risk factors that promote atherosclerosis, is unknown.
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A description of shock attenuation for children running.
J Athl Train
PUBLISHED: 05-08-2010
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A growing number of children are participating in organized sport activities, resulting in a concomitant increase in lower extremity injuries. Little is known about the impact generated when children are running or how this impact is attenuated in child runners.
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Slip-sliding away: serial changes and homoplasy in repeat number in the Drosophila yakuba homolog of human cancer susceptibility gene BRCA2.
PLoS ONE
PUBLISHED: 04-20-2010
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Several recent studies have examined the function and evolution of a Drosophila homolog to the human breast cancer susceptibility gene BRCA2, named dmbrca2. We previously identified what appeared to be a recent expansion in the RAD51-binding BRC-repeat array in the ancestor of Drosophila yakuba. In this study, we examine patterns of variation and evolution of the dmbrca2 BRC-repeat array within D. yakuba and its close relatives. We develop a model of how unequal crossing over may have produced the expanded form, but we also observe short repeat forms, typical of other species in the D. melanogaster group, segregating within D. yakuba and D. santomea. These short forms do not appear to be identical-by-descent, suggesting that the history of dmbrca2 in the D. melanogaster subgroup has involved repeat unit contractions resulting in homoplasious forms. We conclude that the evolutionary history of dmbrca2 in D. yakuba and perhaps in other Drosophila species may be more complicated than can be inferred from examination of the published single genome sequences per species.
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The effects of speed and surface compliance on shock attenuation characteristics for male and female runners.
J Appl Biomech
PUBLISHED: 10-16-2009
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The purpose of the study was to examine the effects of running speed and surface compliance on shock attenuation (SA) characteristics for male and female runners. We were also interested in identifying possible kinematic explanations, specifically, kinematics of the lower extremity at foot-ground contact, for anticipated gender differences in SA. Fourteen volunteer recreational runners (7 male, 7 female) ran at preferred and slow speeds on an adjustable bed treadmill, which simulated soft, medium, and hard surface conditions. Selected kinematic descriptors of lower extremity kinematics as well as leg and head peak impact acceleration values were obtained for 10 left leg contacts per subject-condition. Results identified significant SA values between genders across conditions and more specifically, across surfaces for females, with male runners demonstrating a similar trend. Regression modeling to predict SA by gender for surface conditions elicited unremarkable results, ranging from 30.9 to 59.9% explained variance. It appears that surface compliance does affect SA during running; however, the runners ability to dissipate the shock wave may not be expressly explained by our definition of lower extremity kinematics at contact.
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Insight into muscle activity during deep water running.
Med Sci Sports Exerc
PUBLISHED: 09-04-2009
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The purpose of this study was to compare muscle activity and patterns during deep water running (DWR) and treadmill running (TMR) at equivalent levels of RPE.
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Discovering the elusive underlying cause of a bilateral effusion combined with ascites.
Proc (Bayl Univ Med Cent)
PUBLISHED: 07-28-2009
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A 77-year-old Asian man presented to the emergency department with bilateral pleural effusion and ascites accompanied with generalized weakness, dyspnea, tachycardia, and tachypnea. After an extensive workup that ruled out heart failure, pulmonary embolism, pneumonia, and malignancy-including extensive laboratory tests, electrocardiograms, chest x-ray, computed tomographic angiogram, computed tomography scans of the abdomen and pelvis, colonoscopy, thoracentesis, paracentesis, and exploratory laparoscopy-an elusive peritoneal tuberculosis was successfully identified. This case suggests that clinicians should consider extrapulmonary tuberculosis in their practice, given increasing immigration and the variety of populations present in our society. When tuberculosis is suspected, a negative smear for acid-fast bacillus, a lack of granulomas on histopathology, and failure to culture Mycobacterium tuberculosis do not exclude the diagnosis. Exploratory laparoscopy or minilaparotomy has a high level of sensitivity and specificity so should be considered.
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RNase 1 genes from the family Sciuridae define a novel rodent ribonuclease cluster.
Mamm. Genome
PUBLISHED: 04-07-2009
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The RNase A ribonucleases are a complex group of functionally diverse secretory proteins with conserved enzymatic activity. We have identified novel RNase 1 genes from four species of squirrel (order Rodentia, family Sciuridae). Squirrel RNase 1 genes encode typical RNase A ribonucleases, each with eight cysteines, a conserved CKXXNTF signature motif, and a canonical His(12)-Lys(41)-His(119) catalytic triad. Two alleles encode Callosciurus prevostii RNase 1, which include a Ser(18)<-->Pro, analogous to the sequence polymorphisms found among the RNase 1 duplications in the genome of Rattus exulans. Interestingly, although the squirrel RNase 1 genes are closely related to one another (77-95% amino acid sequence identity), the cluster as a whole is distinct and divergent from the clusters including RNase 1 genes from other rodent species. We examined the specific sites at which Sciuridae RNase 1s diverge from Muridae/Cricetidae RNase 1s and determined that the divergent sites are located on the external surface, with complete sparing of the catalytic crevice. The full significance of these findings awaits a more complete understanding of biological role of mammalian RNase 1s.
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Automated synthesis of an 18F-labelled pyridine-based alkylating agent for high yield oligonucleotide conjugation.
Appl Radiat Isot
PUBLISHED: 03-25-2009
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Alkylating agents have been shown to be very promising for the radiolabelling of oligonucleotides with fluorine-18. In this report we describe the fully automated synthesis of 2-bromo-N-[3-(2-[(18)F]fluoropyridin-3-yloxy)propyl]acetamide ([(18)F]FPyBrA) utilizing a modular synthesis unit. Reaction conditions for the coupling of this pyridine-based alkylating agent at the 5 end of a fully phosphorothioated random 20-mer DNA sequence were optimized to achieve very high radiochemical yields (>90%) and a maximum specific activity of 5-6 GBq/micromoL. The potential for rapid purification by solid phase extraction without need of chromatographic isolation of the radiolabelled oligonucleotide presents an overall benefit for the application of oligonucleotides in preclinical studies and potential clinical applications.
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Effect of thyroid hormone T3 on myosin-Va expression in the central nervous system.
Brain Res.
PUBLISHED: 03-23-2009
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Thyroid hormones (THs) are essential for brain development, where they regulate gliogenesis, myelination, cell proliferation and protein synthesis. Hypothyroidism severely affects neuronal growth and establishment of synaptic connections. Triiodothyronine (T3), the biologically active form of TH, has a central function in these activities. So, Myosin-Va (Myo-Va), a molecular motor protein involved in vesicle and RNA transport, is a good candidate as a target for T3 regulation. Here, we analyzed Myo-Va expression in euthyroid and hypothyroid adult rat brains and synaptosomes. We observed a reduction of Myo-Va expression in cultured neural cells from newborn hypothyroid rat brain, while immunocytochemical experiments showed a punctate distribution of this protein in the cytoplasm of cells. Particularly, Myo-Va co-localized with microtubules in neurites, especially in their varicosities. Myo-Va immunostaining was stronger in astrocytes and neurons of controls when compared with hypothyroid brains. In addition, supplementation of astrocyte cultures with T3 led to increased expression of Myo-Va in cells from both euthyroid and hypothyroid animals, suggesting that T3 modulates Myo-Va expression in neural cells both in vivo and in vitro. We have further analyzed Myo-Va expression in U373 cells, a human glioblastoma line, and found the same punctate cytoplasmic protein localization. As in normal neural cells, this expression was also increased by T3, suggesting that the modulatory mechanism exerted by T3 over Myo-Va remains active on astrocyte tumor cells. These data, coupled with the observation that Myo-Va is severely affected in hypothyroidism, support the hypothesis that T3 activity regulates neural motor protein expression, taking Myo-Va as a model. As a consequence, reduced T3 activity could supposedly affect axonal transport and synaptic function, and could therefore explain disturbances seen in the hypothyroid brain.
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Portal vein embolization with radiolabeled polyvinyl alcohol particles in a swine model: hepatic distribution and implications for pancreatic islet cell transplantation.
Cardiovasc Intervent Radiol
PUBLISHED: 01-28-2009
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The distribution of radiolabeled polyvinyl alcohol microspheres (PVAMs) when infused into the portal vein of domestic swine was investigated, with the purpose of assessing implications for pancreatic islet cell transplantation. PVAMs measuring 100-300 microm (Contour SE) and labeled with (99m)Tc were infused into the main portal vein of 12 swine, with intermittent portal venous pressure measurements. The infusion catheter was introduced antegradely via direct or indirect cannulation of the portal vein. The liver was subsequently divided into anatomical segments. Radioactivity (decay corrected) was measured for (99m)Tc microsphere synthesis, dose preparation, gross organ activities, tissue samples, and blood. Particulate labeling, catheter positioning, and infusion were successful in all cases. The number of particles used was (185,000 +/- 24,000) with a volume of 1 ml. Mean portal pressure at 5 min was significantly higher than baseline, but without a significant difference at 15 min. Extrahepatic tissue and serum radioactivity was negligible. A significant difference in number of radioactive particles per gram was detected between segments 6/7 and segments 5/8. Intrasegmental activity was analyzed, and for segments 2/3 a significant difference in the percentage dose per gram across samples was demonstrated (P = 0.001). Effective and stable radiolabeling of PVAMs with (99m)Tc-sulfur colloid was demonstrated. Portal venous infusion of 100- to 300-microm particles showed entrapment in the sinusoidal hepatic system with transient portal pressure elevation. Preferential embolization into the right lateral and posterior segments occurs, suggesting that flow dynamics/catheter tip position plays a role in particle distribution.
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Vascular smooth muscle cell sirtuin 1 protects against DNA damage and inhibits atherosclerosis.
Circulation
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Vascular smooth muscle cells (VSMCs) in human atherosclerosis manifest extensive DNA damage and activation of the DNA damage response, a pathway that coordinates cell cycle arrest and DNA repair, or can trigger apoptosis or cell senescence. Sirtuin 1 deacetylase (SIRT1) regulates cell ageing and energy metabolism and regulates the DNA damage response through multiple targets. However, the direct role of SIRT1 in atherosclerosis and how SIRT1 in VSMCs might regulate atherosclerosis are unknown.
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Muscle activity during different styles of deep water running and comparison to treadmill running at matched stride frequency.
Gait Posture
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The purpose of this study was to compare muscle activity during deep water running (DWR) and treadmill running on dry land (TMR) as well as to investigate effect of stride frequency (SF) on muscle activity while using different styles of DWR (high-knee and cross-country styles, DWR-HK and DWR-CC, respectively). Eight subjects participated in this study. The baseline condition consisted of TMR at the preferred stride frequency (PSF). The remaining conditions consisted of DWR-HK and DWR-CC at PSF, PSF-15%, and PSF+15%. Muscle activity was recorded from the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius. Rectus femoris and biceps femoris muscle activity during DWR-CC-PSF were significantly greater than that of TMR-PSF (P<0.05). However, rectus femoris muscle activity during DWR-HK-PSF was significantly lower than that of TMR-PSF (P<0.05). Gastrocnemius muscle activity during both DWR-HK-PSF and DWR-CC-PSF were significantly lower than that of TMR-PSF (P<0.05). Furthermore, muscle activity from all tested muscles during DWR-HK and DWR-CC increased with increasing SF (P<0.05). These observations indicated that muscle activity is influenced not only by running in the water but also by the style of DWR (DWR-HK, DWR-CC) used.
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Integrative structural modelling of the cardiac thin filament: energetics at the interface and conservation patterns reveal a spotlight on period 2 of tropomyosin.
Bioinform Biol Insights
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Cardiomyopathies are a major health problem, with inherited cardiomyopathies, many of which are caused by mutations in genes encoding sarcomeric proteins, constituting an ever-increasing fraction of cases. To begin to study the mechanisms by which these mutations cause disease, we have employed an integrative modelling approach to study the interactions between tropomyosin and actin. Starting from the existing blocked state model, we identified a specific zone on the actin surface which is highly favourable to support tropomyosin sliding from the blocked/closed states to the open state. We then analysed the predicted actin-tropomyosin interface regions for the three states. Each quasi-repeat of tropomyosin was studied for its interaction strength and evolutionary conservation to focus on smaller surface zones. Finally, we show that the distribution of the known cardiomyopathy mutations of ?-tropomyosin is consistent with our model. This analysis provides structural insights into the possible mode of interactions between tropomyosin and actin in the open state for the first time.
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The methyl xanthine caffeine inhibits DNA damage signaling and reactive species and reduces atherosclerosis in ApoE(-/-) mice.
Arterioscler. Thromb. Vasc. Biol.
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Caffeine remains one of the most widely consumed drugs in the world. Caffeine has multiple actions, including inhibition of the DNA damage response, and its metabolites, 1-methylxanthine and 1-methyluric acid, are potent antioxidants. Combined, these properties can exert direct effects on cell proliferation, cell death, inflammation, and DNA repair, all important processes that occur in atherosclerosis.
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Evaluation of phosphatidylserine-binding peptides targeting apoptotic cells.
J Biomol Screen
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The inhibition or dysregulation of apoptosis plays an intimate role in the initiation and progression of cancer by confounding normal tissue homeostasis. We currently do not have a clinical method to assess apoptosis induced by cancer therapies. Phosphatidylserine (PS) is an attractive target for imaging apoptosis because it is on the exterior of the apoptotic cells and PS externalization is an early marker of apoptosis. PS-binding peptides are an attractive option for developing an imaging probe to detect apoptosis using positron emission tomography. In this study, four peptides were evaluated for PS-binding characteristics using a plate-based assay system, a liposome mimic of cell membrane PS presentation, and a cell assay of apoptosis. This work also describes two screening techniques to enable researchers to identify and optimize compounds that bind to PS. The results of our study indicate that all four peptides bind to PS and are specific to apoptotic cells. Two of the peptides in particular that have an additional cysteine residue are good potential candidates for development into imaging probes because they bind to PS with high affinity and specificity and they can be easily radiolabelled with (18)F.
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Impact characteristics of female children running in adult versus youth shoes of the same size.
J Appl Biomech
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The purpose of this study was to determine if ground reaction forces were influenced by shoe design (adult vs. youth) for female children when running. Subjects (n = 10, 12.0 ± 1.1 years old; 154 ± 4.9 cm; 46.2 ± 14.3 kg; shoe size 3.5-7 youth) were fit with a shoe model available in youth and adult sizes. Subjects ran 10 trials per shoe condition across a force platform placed in the middle of a 9-m runway. Impact force, second maximum force, loading rate, stance time and average vertical ground reaction forces were recorded for each trial. Shoes underwent a mechanical impact test with peak force, peak acceleration, and percent energy returned recorded. Each variable was compared between shoe conditions. From the impact testing, it was determined that peak force, peak acceleration and percent energy return were 7.1%, 7.1%, and 18.9% greater, respectively, for the youth vs. adult shoe (p < .001). From the running tests, it was determined that loading rate was different (p = .009) between shoe conditions whereas impact force, second maximum force, average force and stance time were not different between shoes (p > .01). Young girls had a greater loading rate when running in youth vs. adult shoes even though the shoe size was the same.
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Mitochondria in vascular disease.
Cardiovasc. Res.
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Mitochondria are often regarded as the powerhouse of the cell by generating the ultimate energy transfer molecule, ATP, which is required for a multitude of cellular processes. However, the role of mitochondria goes beyond their capacity to create molecular fuel, to include the generation of reactive oxygen species, the regulation of calcium, and activation of cell death. Mitochondrial dysfunction is part of both normal and premature ageing, but can contribute to inflammation, cell senescence, and apoptosis. Cardiovascular disease, and in particular atherosclerosis, is characterized by DNA damage, inflammation, cell senescence, and apoptosis. Increasing evidence indicates that mitochondrial damage and dysfunction also occur in atherosclerosis and may contribute to the multiple pathological processes underlying the disease. This review summarizes the normal role of mitochondria, the causes and consequences of mitochondrial dysfunction, and the evidence for mitochondrial damage and dysfunction in vascular disease. Finally, we highlight areas of mitochondrial biology that may have therapeutic targets in vascular disease.
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Poor maternal nutrition programmes a pro-atherosclerotic phenotype in ApoE-/- mice.
Clin. Sci.
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Numerous animal studies have consistently shown that early life exposure to LP (low-protein) diet programmes risk factors for CVD (cardiovascular disease) such as dyslipidaemia, high BP (blood pressure) and cardiac dysfunction in the offspring. However, studies on the effect of maternal under-nutrition on offspring development of atherosclerosis are scarce. Applying our LP model to the ApoE(-/-) atherosclerosis-prone mouse model, we investigated the development of atherosclerotic lesions in the aortic root of 6-month-old offspring. In addition, markers of plaque progression including SMA (smooth muscle actin) and Mac3 (macrophage marker 3) were studied. Pregnant dams were fed on a control (20% protein) or on an isocaloric LP diet (8% protein) throughout pregnancy and lactation. After weaning, male offspring were maintained on 20% normal laboratory chow. At 6 months of age, LP offspring showed a significantly greater plaque area (P<0.05) with increased cholesterol clefts and significantly higher indices of DNA damage compared with controls (P<0.05). The expression of HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-CoA reductase) (P<0.05) and LDL (low-density lipoprotein) receptor in the liver of LP offspring were increased. Furthermore, LP offspring had higher LDL-cholesterol levels (P<0.05) and a trend towards elevated insulin. There were no differences in other lipid measurements and fasting glucose between groups. These observations suggest that early exposure to an LP diet accelerates the development and increases the progression of atherosclerotic lesions in young adult offspring. Future studies are needed to elucidate the specific mechanisms linking in utero exposure to a diet low in protein to the development of atherosclerosis.
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Myosin Va associates with mRNA in ribonucleoprotein particles present in myelinated peripheral axons and in the central nervous system.
Dev Neurobiol
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Sorting of specific mRNAs to particular cellular locations and regulation of their translation is an essential mechanism underlying cell polarization. The transport of RNAs by kinesins and dyneins has been clearly established in several cell models, including neurons in culture. A similar role appears to exist in higher eukaryotes for the myosins. Myosin Va (Myo5a) has been described as a component of ribonucleoprotein particles (RNPs) in the adult rat nervous system and associated to ZBP1 and ribosomes in ribosomal periaxoplasmic plaques (PARPs), making it a likely candidate for mediating some aspects of RNA transport in neurons. To test this hypothesis, we have characterized RNPs containing Myo5a in adult brains of rats and mice. Microarray analysis of RNAs coimmunoprecipitated with Myo5a indicates that this motor may associate with a specific subpopulation of neuronal mRNAs. We found mRNAs encoding ã-synuclein and several proteins with functions in translation in these RNPs. Immunofluorescence analyses of RNPs showed apparent co-localization of Myo5a with ribosomes, mRNA and RNA-binding proteins in discrete structures present both in axons of neurons in culture and in myelinated fibers of medullary roots. Our data suggest that PARPs include RNPs bearing the mRNA coding for Myo5a and are equipped with kinesin and Myo5a molecular motors. In conclusion, we suggest that Myo5a is involved in mRNA trafficking both in the central and peripheral nervous systems. © 2013 Wiley Periodicals, Inc. Develop Neurobiol, 2013.
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