1,544 research outputs found
AMP-Activated Kinase AMPK Is Expressed in Boar Spermatozoa and Regulates Motility
The main functions of spermatozoa required for fertilization are dependent on the energy status and metabolism. AMP-activated kinase, AMPK, acts a sensor and regulator of cell metabolism. As AMPK studies have been focused on somatic cells, our aim was to investigate the expression of AMPK protein in spermatozoa and its possible role in regulating motility. Spermatozoa from boar ejaculates were isolated and incubated under different conditions (38,5°C or 17°C, basal medium TBM or medium with Ca2+ and bicarbonate TCM, time from 1â24 hours) in presence or absence of AMPK inhibitor, compound C (CC, 30 ”M). Western blotting reveals that AMPK is expressed in boar spermatozoa at relatively higher levels than in somatic cells. AMPK phosphorylation (activation) in spermatozoa is temperature-dependent, as it is undetectable at semen preservation temperature (17°C) and increases at 38,5°C in a time-dependent manner. AMPK phosphorylation is independent of the presence of Ca2+ and/or bicarbonate in the medium. We confirm that CC effectively blocks AMPK phosphorylation in boar spermatozoa. Analysis of spermatozoa motility by CASA shows that CC treatment either in TBM or in TCM causes a significant reduction of any spermatozoa motility parameter in a time-dependent manner. Thus, AMPK inhibition significantly decreases the percentages of motile and rapid spermatozoa, significantly reduces spermatozoa velocities VAP, VCL and affects other motility parameters and coefficients. CC treatment does not cause additional side effects in spermatozoa that might lead to a lower viability even at 24 h incubation. Our results show that AMPK is expressed in spermatozoa at high levels and is phosphorylated under physiological conditions. Moreover, our study suggests that AMPK regulates a relevant function of spermatozoa, motility, which is essential for their ultimate role of fertilization
Principles of Glomerular Organization in the Human Olfactory Bulb â Implications for Odor Processing
Olfactory sensory neurons (OSN) in mice express only 1 of a possible 1,100 odor receptors (OR) and axons from OSNs expressing the same odor receptor converge into âŒ2 of the 1,800 glomeruli in each olfactory bulb (OB) in mice; this yields a convergence ratio that approximates 2â¶1, 2 glomeruli/OR. Because humans express only 350 intact ORs, we examined human OBs to determine if the glomerular convergence ratio of 2â¶1 established in mice was applicable to humans. Unexpectedly, the average number of human OB glomeruli is >5,500 yielding a convergence ratio of âŒ16â¶1. The data suggest that the initial coding of odor information in the human OB may differ from the models developed for rodents and that recruitment of additional glomeruli for subpopulations of ORs may contribute to more robust odor representation
Membrane Cholesterol Regulates Lysosome-Plasma Membrane Fusion Events and Modulates Trypanosoma cruzi Invasion of Host Cells
Trypanosoma cruzi, is the etiological agent of a neglected tropical malady known as Chagas' disease, which affects about 8 million people in Latin America. 30â40% of affected individuals develop a symptomatic chronic infection, with cardiomyopathy being the most prevalent condition. T. cruzi utilizes an interesting strategy for entering cells: T. cruzi enhances intracellular calcium levels, which in turn trigger the exocytosis of lysosomal contents. Lysosomes then donate their membrane for the formation of the parasitophorous vacuole. Membrane rafts, cholesterol-enriched microdomains in the host cell plasma membrane, have also been implicated in T. cruzi invasion process. Since both plasma membrane and lysosomes collaborate in parasite invasion, we decided to study the importance of these membrane domains for lysosomal recruitment and fusion during T. cruzi invasion into host cells. Our results show that drug dependent depletion of plasma membrane cholesterol changes raft organization and induces excessive lysosome exocytosis in the earlier stages of treatment, leading to a depletion of lysosomes near the cell cortex, which in turn compromises T. cruzi invasion. Based on these results, we propose that cholesterol depletion leads to unregulated exocytic events of pre-docked lysosomes, reducing lysosome availability at the cell cortex and consequently compromising T. cruzi infection
Unexpectedly high burden of rotavirus gastroenteritis in very young infants
<p>Abstract</p> <p>Background</p> <p>The highest incidence of rotavirus gastroenteritis has generally been reported in children 6-24 months of age. Young infants are thought to be partially protected by maternal antibodies acquired transplacentally or via breast milk. The purpose of our study was to assess the age distribution of children with confirmed community-acquired rotavirus gastroenteritis presenting to an urban referral hospital.</p> <p>Methods</p> <p>Children presenting to The Children's Hospital of Philadelphia with acute gastroenteritis have been monitored for the presence of rotavirus antigen in the stool by ELISA (followed by genotyping if ELISA-positive) since the 1994-95 epidemic season.</p> <p>Results</p> <p>Over the last 12 rotavirus seasons prior to the introduction of the pentavalent rotavirus vaccine in 2006, stool specimens from 1646 patients tested positive for community-acquired rotavirus infection. Gender or age was not recorded in 6 and 5 cases, respectively. Overall, 58% of the cases occurred in boys. G1 was the predominant VP7 serotype, accounting for 72% of cases. The median (IQR) age was 11 (5-21) months. A total of 790 (48%) cases occurred in children outside the commonly quoted peak age range, with 27% in infants <6 months of age and 21% in children >24 months of age. A total of 220 (13%) cases occurred during the first 3 months of life, and the highest number of episodes per month of age [97 (6%)] was observed during the second month of life.</p> <p>Conclusions</p> <p>The incidence of community-acquired rotavirus gastroenteritis monitored over 12 seasons in the prevaccine era at a major university hospital was nearly constant for each month of age during the first year of life, revealing an unexpectedly high incidence of symptomatic rotavirus disease in infants <3 months old. A sizeable fraction of cases occurred in children too young to have been vaccinated according to current recommendations.</p
Silicon particles as trojan horses for potential cancer therapy
[EN] Background: Porous silicon particles (PSiPs) have been used extensively as drug delivery systems, loaded with chemical species for disease treatment. It is well known from silicon producers that silicon is characterized by a low reduction potential, which in the case of PSiPs promotes explosive oxidation reactions with energy yields exceeding that of trinitrotoluene (TNT). The functionalization of the silica layer with sugars prevents its solubilization, while further functionalization with an appropriate antibody enables increased bioaccumulation inside selected cells. Results: We present here an immunotherapy approach for potential cancer treatment. Our platform comprises the use of engineered silicon particles conjugated with a selective antibody. The conceptual advantage of our system is that after reaction, the particles are degraded into soluble and excretable biocomponents. Conclusions: In our study, we demonstrate in particular, specific targeting and destruction of cancer cells in vitro. The fact that the LD50 value of PSiPs-HER-2 for tumor cells was 15-fold lower than the LD50 value for control cells demonstrates very high in vitro specificity. This is the first important step on a long road towards the design and development of novel chemotherapeutic agents against cancer in general, and breast cancer in particular.The authors acknowledge financial support from the following projects FIS2009-07812, MAT2012-35040, PROMETEO/2010/043, CTQ2011-23167, CrossSERS, FP7 MC-IEF 329131, and HSFP (project RGP0052/2012) and Medcom Tech SA. Xiang Yu acknowledges support by the Chinese government (CSC, Nr. 2010691036).Fenollosa Esteve, R.; Garcia-Rico, E.; Alvarez, S.; Alvarez, R.; Yu, X.; Rodriguez, I.; Carregal-Romero, S.... (2014). Silicon particles as trojan horses for potential cancer therapy. Journal of Nanobiotechnology. 12:1-10. https://doi.org/10.1186/s12951-014-0035-7S11012Prasad PN: Introduction to Nanomedicine and Nanobioengineering. Wiley, New York, 2012.Randall CL, Leong TG, Bassik N, Gracias DH: 3D lithographically fabricated nanoliter containers for drug delivery. Adv Drug Del Rev. 2007, 59: 1547-1561. 10.1016/j.addr.2007.08.024.Reibetanz U, Chen MHA, Mutukumaraswamy S, Liaw ZY, Oh BHL, Venkatraman S, Donath E, Neu BR: Colloidal DNA carriers for direct localization in cell compartments by pH sensoring. Biogeosciences. 2010, 11: 1779-1784.Tasciotti E, Liu X, Bhavane R, Plant K, Leonard AD, Price BK, Cheng MM-C, Decuzzi P, Tour JM, Robertson F, Ferrari M: Mesoporous silicon particles as a multistage delivery system for imaging and therapeutic applications. Nat Nano. 2008, 3: 151-157. 10.1038/nnano.2008.34.Park J-H, Gu L, von Maltzahn G, Ruoslahti E, Bhatia SN, Sailor MJ: Biodegradable luminescent porous silicon nanoparticles for in vivo applications. Nat Mater. 2009, 8: 331-336. 10.1038/nmat2398.Hong C, Lee J, Son M, Hong SS, Lee C: In-vivo cancer cell destruction using porous silicon nanoparticles. Anti-Cancer Drugs. 2011, 22: 971-977. 910.1097/CAD.1090b1013e32834b32859cCanham LT: Device Comprising Resorbable Silicon for Boron Capture Neutron Therapy. UK Patent Nr. 0302283.7. Book Device Comprising Resorbable Silicon for Boron Capture Neutron Therapy. UK Patent Nr. 0302283.7 (Editor ed.^eds.). 2003, UK Patent Nr. 0302283.7, CityXiao L, Gu L, Howell SB, Sailor MJ: Porous silicon nanoparticle photosensitizers for singlet oxygen and their phototoxicity against cancer cells. ACS Nano. 2011, 5: 3651-3659. 10.1021/nn1035262.Gil PR, Parak WJ: Composite nanoparticles take Aim at cancer. ACS Nano. 2008, 2: 2200-2205. 10.1021/nn800716j.Gomella LG: Is interstitial hyperthermia a safe and efficacious adjunct to radiotherapy for localized prostate cancer?. Nat Clin Pract Urol. 2004, 1: 72-73. 10.1038/ncpuro0041.Maier-Hauff K, Ulrich F, Nestler D, Niehoff H, Wust P, Thiesen B, Orawa H, Budach V, Jordan A: Efficacy and safety of intratumoral thermotherapy using magnetic iron-oxide nanoparticles combined with external beam radiotherapy on patients with recurrent glioblastoma multiforme. J Neuro-Oncol. 2011, 103: 317-324. 10.1007/s11060-010-0389-0.Lal S, Clare SE, Halas NJ: Nanoshell-enabled photothermal cancer therapy: Impending clinical impact. Acc Chem Res. 2008, 41: 1842-1851. 10.1021/ar800150g.Lee C, Kim H, Hong C, Kim M, Hong SS, Lee DH, Lee WI: Porous silicon as an agent for cancer thermotherapy based on near-infrared light irradiation. J Mater Chem. 2008, 18: 4790-4795. 10.1039/b808500e.Osminkina LA, Gongalsky MB, Motuzuk AV, Timoshenko VY, Kudryavtsev AA: Silicon nanocrystals as photo- and sono-sensitizers for biomedical applications. Appl Phys B. 2011, 105: 665-668. 10.1007/s00340-011-4562-8.Jain PK, Huang X, El-Sayed IH, El-Sayed MA: Noble metals on the nanoscale: optical and photothermal properties and some applications in imaging, sensing, biology, and medicine. Acc Chem Res. 2008, 41: 1578-1586. 10.1021/ar7002804.Serda RE, Godin B, Blanco E, Chiappini C, Ferrari M: Multi-stage delivery nano-particle systems for therapeutic applications. Biochim Biophys Acta. 1810, 2011: 317-329.Xu R, Huang Y, Mai J, Zhang G, Guo X, Xia X, Koay EJ, Qin G, Erm DR, Li Q, Liu X, Ferrari M, Shen H: Multistage vectored siRNA targeting ataxia-telangiectasia mutated for breast cancer therapy. Small. 2013, 9: 1799-1808. 10.1002/smll.201201510.Park JS, Kinsella JM, Jandial DD, Howell SB, Sailor MJ: Cisplatin-loaded porous Si microparticles capped by electroless deposition of platinum. Small. 2011, 7: 2061-2069. 10.1002/smll.201100438.Xue M, Zhong X, Shaposhnik Z, Qu Y, Tamanoi F, Duan X, Zink JI: pH-operated mechanized porous silicon nanoparticles. J Am Chem Soc. 2011, 133: 8798-8801. 10.1021/ja201252e.Canham LT: Bioactive silicon structure fabrication through nanoetching techniques. Adv Mater. 1995, 7: 1033-1037. 10.1002/adma.19950071215.Popplewell JF, King SJ, Day JP, Ackrill P, Fifield LK, Cresswell RG, Di Tada ML, Liu K: Kinetics of uptake and elimination of silicic acid by a human subject: a novel application of 32Si and accelerator mass spectrometry. J Inorganic Biochem. 1998, 69: 177-180. 10.1016/S0162-0134(97)10016-2.Shabir Q, Pokale A, Loni A, Johnson DR, Canham LT, Fenollosa R, Tymczenko M, Rodr guez I, Meseguer F, Cros A, Cantarero A: Medically biodegradable hydrogenated amorphous silicon microspheres. Silicon. 2011, 3: 173-176. 10.1007/s12633-011-9097-4.Chen Y, Wan Y, Wang Y, Zhang H, Jiao Z: Anticancer efficacy enhancement and attenuation of side effects of doxorubicin with titanium dioxide nanoparticles. Int J Nanomed. 2011, 6: 2321-2326.Mackowiak SA, Schmidt A, Weiss V, Argyo C, von Schirnding C, Bein T, BrĂ€uchle C: Targeted drug delivery in cancer cells with Red-light photoactivated mesoporous silica nanoparticles. Nano Lett. 2013, 13: 2576-2583. 10.1021/nl400681f.Li Z, Barnes JC, Bosoy A, Stoddart JF, Zink JI: Mesoporous silica nanoparticles in biomedical applications. Chem Soc Rev. 2012, 41: 2590-2605. 10.1039/c1cs15246g.O Mara WC, Herring B, Hunt P: Handbook of Semiconductor Silicon Technology. Noyes Publication, New Jersey, 1990.Mikulec FV, Kirtland JD, Sailor MJ: Explosive nanocrystalline porous silicon and its Use in atomic emission spectroscopy. Adv Mater. 2002, 14: 38-41. 10.1002/1521-4095(20020104)14:13.0.CO;2-Z.Clement D, Diener J, Gross E, Kunzner N, Timoshenko VY, Kovalev D: Highly explosive nanosilicon-based composite materials. Phys Stat Sol A. 2005, 202: 1357-1359. 10.1002/pssa.200461102.Canham LT: Silicon quantum wire array fabrication by electrochemical and chemical dissolution of wafers. Appl Phys Lett. 1990, 57: 1046-1049. 10.1063/1.103561.Canham LT: Properties of Porous Silicon. INSPEC, United Kindom, 1997.Heinrich JL, Curtis CL, Credo GM, Sailor MJ, Kavanagh KL: Luminescent colloidal silicon suspensions from porous silicon. Science. 1992, 255: 66-68. 10.1126/science.255.5040.66.Littau KA, Szajowski PJ, Muller AJ, Kortan AR, Brus LE: A luminescent silicon nanocrystal colloid via a high-temperature aerosol reaction. J Phys Chem. 1993, 97: 1224-1230. 10.1021/j100108a019.Menz WJ, Shekar S, Brownbridge GPE, Mosbach S, KĆrmer R, Peukert W, Kraft M: Synthesis of silicon nanoparticles with a narrow size distribution: a theoretical study. J Aerosol Sci. 2012, 44: 46-61. 10.1016/j.jaerosci.2011.10.005.Swihart MT, Girshick SL: Thermochemistry and kinetics of silicon hydride cluster formation during thermal decomposition of silane. J Phys Chem B. 1998, 103: 64-76. 10.1021/jp983358e.Fenollosa R, Ramiro-Manzano F, Tymczenko M, Meseguer F: Porous silicon microspheres: synthesis, characterization and application to photonic microcavities. J Mater Chem. 2010, 20: 5210-5214. 10.1039/c0jm00079e.Ramiro-Manzano F, Fenollosa R, XifrĂ©-PĂ©rez E, GarĂn M, Meseguer F: Porous silicon microcavities based photonic barcodes. Adv Mater. 2011, 23: 3022-3025. 10.1002/adma.201100986.Kastl L, Sasse D, Wulf V, Hartmann R, Mircheski J, Ranke C, Carregal-Romero S, MartĂnez-LĂłpez JA, FernĂĄndez-ChacĂłn R, Parak WJ, Elsasser HP, Rivera-Gil P: Multiple internalization pathways of polyelectrolyte multilayer capsules into mammalian cells. ACS Nano. 2013, 7: 6605-6618. 10.1021/nn306032k.Schweiger C, Hartmann R, Zhang F, Parak W, Kissel T, Rivera_Gil P: Quantification of the internalization patterns of superparamagnetic iron oxide nanoparticles with opposite charge. J Nanobiotech. 2012, 10: 28-10.1186/1477-3155-10-28.Sanles-Sobrido M, Exner W, Rodr guez-Lorenzo L, RodrĂguez-GonzĂlez B, Correa-Duarte MA, Ălvarez-Puebla RA, Liz-MarzĂĄn LM: Design of SERS-encoded, submicron, hollow particles through confined growth of encapsulated metal nanoparticles. J Am Chem Soc. 2009, 131: 2699-2705. 10.1021/ja8088444.Slamon D, Eiermann W, Robert N, Pienkowski T, Martin M, Press M, Mackey J, Glaspy J, Chan A, Pawlicki M, Pinter T, Valero V, Liu MC, Sauter G, von Minckwitz G, Visco F, Bee V, Buyse M, Bendahmane B, Tabah-Fisch I, Lindsay MA, Riva A, Crown J: Adjuvant trastuzumab in HER2-positive breast cancer. N Engl J Med. 2011, 365: 1273-1283. 10.1056/NEJMoa0910383.Agus DB, Gordon MS, Taylor C, Natale RB, Karlan B, Mendelson DS, Press MF, Allison DE, Sliwkowski MX, Lieberman G, Kelsey SM, Fyfe G: Phase I clinical study of pertuzumab, a novel HER dimerization inhibitor, in patients with advanced cancer. J Clin Oncol. 2005, 23: 2534-2543. 10.1200/JCO.2005.03.184.Colombo M, Mazzucchelli S, Montenegro JM, Galbiati E, Corsi F, Parak WJ, Prosperi D: Protein oriented ligation on nanoparticles exploiting O6-alkylguanine-DNA transferase (SNAP) genetically encoded fusion. Small. 2012, 8: 1492-1497. 10.1002/smll.201102284.Franklin MC, Carey KD, Vajdos FF, Leahy DJ, de Vos AM, Sliwkowski MX: Insights into ErbB signaling from the structure of the ErbB2-pertuzumab complex. Cancer Cell. 2004, 5: 317-328. 10.1016/S1535-6108(04)00083-2.Paris L, Cecchetti S, Spadaro F, Abalsamo L, Lugini L, Pisanu ME, Lorio E, Natali PG, Ramoni C, Podo F: Inhibition of phosphatidylcholine-specific phospholipase C downregulates HER2 overexpression on plasma membrane of breast cancer cells. Breast Cancer Res. 2010, 12: R27-10.1186/bcr2575.Fenollosa R, Meseguer F, Tymczenko M: Silicon colloids: from microcavities to photonic sponges. Adv Mater. 2008, 20: 95-98. 10.1002/adma.200701589.Jasinski JM, Gates SM: Silicon chemical vapor deposition one step at a time: fundamental studies of silicon hydride chemistry. Acc Chem Res. 1991, 24: 9-15. 10.1021/ar00001a002.Xiao Q, Liu Y, Qiu Y, Zhou G, Mao C, Li Z, Yao Z-J, Jiang S: Potent antitumor mimetics of annonaceous acetogenins embedded with an aromatic moiety in the left hydrocarbon chain part. J Med Chem. 2010, 54: 525-533. 10.1021/jm101053k.Allman SA, Jensen HH, Vijayakrishnan B, Garnett JA, Leon E, Liu Y, Anthony DC, Sibson NR, Feizi T, Matthews S, Davis BG: Potent fluoro-oligosaccharide probes of adhesion in toxoplasmosis. ChemBioChem. 2009, 10: 2522-2529. 10.1002/cbic.200900425.Chambers DJ, Evans GR, Fairbanks AJ: Elimination reactions of glycosyl selenoxides. Tetrahedron. 2004, 60: 8411-8419. 10.1016/j.tet.2004.07.005.Tomabechi Y, Suzuki R, Haneda K, Inazu T: Chemo-enzymatic synthesis of glycosylated insulin using a GlcNAc tag. Bioorg Med Chem. 2010, 18: 1259-1264. 10.1016/j.bmc.2009.12.031.Pastoriza-Santos I, Gomez D, Perez-Juste J, Liz-Marzan LM, Mulvaney P: Optical properties of metal nanoparticle coated silica spheres: a simple effective medium approach. Phys Chem Chem Phys. 2004, 6: 5056-5060. 10.1039/b405157b
Polarimetry of binary systems: polars, magnetic CVs, XRBs
Polarimetry provides key physical information on the properties of
interacting binary systems, sometimes difficult to obtain by any other type of
observation. Indeed, radiation processes such as scattering by free electrons
in the hot plasma above accretion discs, cyclotron emission by mildly
relativistic electrons in the accretion shocks on the surface of highly
magnetic white dwarfs and the optically thin synchrotron emission from jets can
be observed. In this review, I will illustrate how optical/near-infrared
polarimetry allows one to estimate magnetic field strengths and map the
accretion zones in magnetic Cataclysmic Variables as well as determine the
location and nature of jets and ejection events in X-ray binaries.Comment: 26 pages, 16 figures; to be published in Astrophysics and Space
Science Library 460, Astronomical Polarisation from the Infrared to Gamma
Rays, Editors: Mignani, R., Shearer, A., S{\l}owikowska, A., Zane,
A genome scan for milk production traits in dairy goats reveals two new mutations in <i>Dgat1</i> reducing milk fat content
The quantity of milk and milk fat and proteins are particularly important traits in dairy livestock.
However, little is known about the regions of the genome that influence these traits in goats. We
conducted a genome wide association study in French goats and identified 109 regions associated
with dairy traits. For a major region on chromosome 14 closely associated with fat content, the
Diacylglycerol O-Acyltransferase 1 (DGAT1) gene turned out to be a functional and positional candidate
gene. The caprine reference sequence of this gene was completed and 29 polymorphisms were found in
the gene sequence, including two novel exonic mutations: R251L and R396W, leading to substitutions
in the protein sequence. The R251L mutation was found in the Saanen breed at a frequency of 3.5% and
the R396W mutation both in the Saanen and Alpine breeds at a frequencies of 13% and 7% respectively.
The R396W mutation explained 46% of the genetic variance of the trait, and the R251L mutation 6%.
Both mutations were associated with a notable decrease in milk fat content. Their causality was then
demonstrated by a functional test. These results provide new knowledge on the genetic basis of milk
synthesis and will help improve the management of the French dairy goat breeding program
Concepts for the development of person-centred, digitally-enabled, Artificial Intelligence-assisted ARIA care pathways (ARIA 2024)
The traditional healthcare model is focused on diseases (medicine and natural science) and does not acknowledge patients' resources and abilities to be experts in their own life based on their lived experiences. Improving healthcare safety, quality and coordination, as well as quality of life, are important aims in the care of patients with chronic conditions. Person-centred care needs to ensure that people's values and preferences guide clinical decisions. This paper reviews current knowledge to develop (i) digital care pathways for rhinitis and asthma multimorbidity and (ii) digitally-enabled person-centred care (1). It combines all relevant research evidence, including the so-called real-world evidence, with the ultimate goal to develop digitally-enabled, patient-centred care. The paper includes (i) Allergic Rhinitis and its Impact on Asthma (ARIA), a two-decade journey, (ii) Grading of Recommendations, Assessment, Development and Evaluation (GRADE), the evidence-based model of guidelines in airway diseases, (iii) mHealth impact on airway diseases, (iv) from guidelines to digital care pathways, (v) embedding Planetary Health, (vi) novel classification of rhinitis and asthma, (vi) embedding real-life data with population-based studies, (vii) the ARIA-EAACI strategy for the management of airway diseases using digital biomarkers, (viii) Artificial Intelligence, (ix) the development of digitally-enabled ARIA Person-Centred Care and (x) the political agenda. The ultimate goal is to propose ARIA 2024 guidelines centred around the patient in order to make them more applicable and sustainable
- âŠ