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1

Polymer coating of paramagnetic particulates for in vivo oxygen-sensing applications.  

PubMed

Crystalline lithium phthalocyanine (LiPc) can be used to sense oxygen. To enhance biocompatibility/stability of LiPc, we encapsulated LiPc in Teflon AF (TAF), cellulose acetate (CA), and polyvinyl acetate (PVAc) (TAF, previously used to encapsulate LiPc, was a comparator). We identified water-miscible solvents that don't dissolve LiPc crystals, but are solvents for the polymers, and encapsulated crystals by solvent evaporation. Oxygen sensitivity of films was characterized in vitro and in vivo. Encapsulation did not change LiPc oximetry properties in vitro at anoxic conditions or varying partial pressures of oxygen (pO2). EPR linewidth of encapsulated particles was linear with pO2, responding to pO2 changes quickly and reproducibly for dynamic measurements. Encapsulated LiPc was unaffected by biological oxidoreductants, stable in vivo for four weeks. Oximetry, stability and biocompatibility properties of LiPc films were comparable, but both CA and PVAc films are cheaper, and easier to fabricate and handle than TAF films, making them superior. PMID:19083100

Eteshola, Edward; Pandian, Ramasamy P; Lee, Stephen C; Kuppusamy, Periannan

2009-04-01

2

Lifetime-based photoacoustic oxygen sensing in vivo  

PubMed Central

Abstract. The determination of oxygen levels in blood and other tissues in vivo is critical for ensuring proper body functioning, for monitoring the status of many diseases, such as cancer, and for predicting the efficacy of therapy. Here we demonstrate, for the first time, a lifetime-based photoacoustic technique for the measurement of oxygen in vivo, using an oxygen sensitive dye, enabling real time quantification of blood oxygenation. The results from the main artery in the rat tail indicated that the lifetime of the dye, quantified by the photoacoustic technique, showed a linear relationship with the blood oxygenation levels in the targeted artery. PMID:22612143

Ray, Aniruddha; Rajian, Justin Rajesh; Lee, Yong-Eun Koo; Wang, Xueding; Kopelman, Raoul

2012-01-01

3

Solid MRI contrast agents for long-term, quantitative in vivo oxygen sensing  

PubMed Central

Targeted MRI contrast agents have proven useful in research and clinical studies for highlighting specific metabolites and biomarkers [Davies GL, et al. (2013) Chem Commun (Camb) 49(84):9704–9721] but their applicability in serial imaging is limited owing to a changing concentration postinjection. Solid enclosures have previously been used to keep the local concentration of contrast agent constant, but the need to surgically implant these devices limits their use [Daniel K, et al. (2009) Biosens Bioelectron 24(11):3252–3257]. This paper describes a novel class of contrast agent that comprises a responsive material for contrast generation and an injectable polymeric matrix for structural support. Using this principle, we have designed a contrast agent sensitive to oxygen, which is composed of dodecamethylpentasiloxane as the responsive material and polydimethylsiloxane as the matrix material. A rodent inspired-gas model demonstrated that these materials are functionally stable in vivo for at least 1 mo, which represents an order of magnitude improvement over an injection of liquid siloxane [Kodibagkar VD, et al. (2006) Magn Reson Med 55(4):743–748]. We also observed minimal adverse tissue reactions or migration of contrast agents from the initial injection site. This class of contrast agents, thus, represented a new and complementary method to monitor chronic diseases by MRI. PMID:24753603

Liu, Vincent H.; Vassiliou, Christophoros C.; Imaad, Syed M.; Cima, Michael J.

2014-01-01

4

Oxygen sensing and metabolic homeostasis.  

PubMed

Oxygen-sensing mechanisms have evolved to maintain cell and tissue homeostasis since the ability to sense and respond to changes in oxygen is essential for survival. The primary site of oxygen sensing occurs at the level of the carotid body which in response to hypoxia signals increased ventilation without the need for new protein synthesis. Chronic hypoxia activates cellular sensing mechanisms which lead to protein synthesis designed to alter cellular metabolism so cells can adapt to the low oxygen environment without suffering toxicity. The master regulator of the cellular response is hypoxia-inducible factor (HIF). Activation of this system under condition of hypobaric hypoxia leads to weight loss accompanied by increased basal metabolic rate and suppression of appetite. These effects are dose dependent, gender and genetic specific, and results in adverse effects if the exposure is extreme. Hypoxic adipose tissue may represent a unified cellular mechanism for variety of metabolic disorders, and insulin resistance in patients with metabolic syndrome. PMID:25132648

Palmer, Biff F; Clegg, Deborah J

2014-11-01

5

Injectable polymer for in vivo oxygen sensing  

E-print Network

This thesis documents the synthesis and characterization of an elastomeric polymer that is oxygen sensitive and can be interrogated using Magnetic Resonance Imaging (MRI) or Magnetic Resonance (MR) technology to report the ...

Imaad, Syed M. (Syed Muhammad)

2013-01-01

6

Influence of Matrices on Oxygen Sensing of Three Sensing Films with Chemically Conjugated Platinum Porphyrin Probes and Preliminary Application for Monitoring of Oxygen Consumption of Escherichia coli (E. coli)  

PubMed Central

Oxygen sensing films were synthesized by a chemical conjugation of functional platinum porphyrin probes in silica gel, polystyrene (PS), and poly(2-hydroxyethyl methacrylate) (PHEMA) matrices. Responses of the sensing films to gaseous oxygen and dissolved oxygen were studied and the influence of the matrices on the sensing behaviors was investigated. Silica gel films had the highest fluorescence intensity ratio from deoxygenated to oxygenated environments and the fastest response time to oxygen. PHEMA films had no response to gaseous oxygen, but had greater sensitivity and a faster response time for dissolved oxygen than those of PS films. The influence of matrices on oxygen response, sensitivity and response time was discussed. The influence is most likely attributed to the oxygen diffusion abilities of the matrices. Since the probes were chemically immobilized in the matrices, no leaching of the probes was observed from the sensing films when applied in aqueous environment. One sensing film made from the PHEMA matrix was used to preliminarily monitor the oxygen consumption of Escherichia coli (E. coli) bacteria. E. coli cell density and antibiotics ampicillin concentration dependent oxygen consumption was observed, indicating the potential application of the oxygen sensing film for biological application. PMID:21076638

Tian, Yanqing; Shumway, Bradley R.; Gao, Weimin; Youngbull, Cody; Holl, Mark R.; Johnson, Roger H.; Meldrum, Deirdre R.

2010-01-01

7

A miniature inexpensive, oxygen sensing element  

SciTech Connect

An exhaustive study was conducted to determine the feasibility of Nernst-type oxygen sensors based on ceramics containing Bi{sub 2}O{sub 3}. The basic sensor design consisted of a ceramic sensing module sealed into a metal tube. The module accommodated an internal heater and thermocouple. Thermal-expansion-matched metals, adhesives, and seals were researched and developed, consistent with sequential firings during sensor assembly. Significant effort was devoted to heater design/testing and to materials' compatibility with Pt electrodes. A systematic approach was taken to develop all sensor components which led to several design modifications. Prototype sensors were constructed and exhaustively tested. It is concluded that development of Nerst-type oxygen sensors based on Bi{sub 2}O{sub 3} will require much further effort and application of specialized technologies. However, during the course of this 3-year program much progress was reported in the literature on amperometric-type oxygen sensors, and a minor effort was devoted here to this type of sensor based on Bi{sub 2}O{sub 3}. These studies were made on Bi{sub 2}O{sub 3}-based ceramic samples in a multilayer-capacitor-type geometry and amperometric-type oxygen sensing was demonstrated at very low temperatures ({approximately} 160{degree}C). A central advantage here is that these types of sensors can be mass-produced very inexpensively ({approximately} 20--50 cents per unit). Research is needed, however, to develop an optimum diffusion-limiting barrier coating. In summary, the original goals of this program were not achieved due to unforeseen problems with Bi{sub 2}O{sub 3}-based Nernst sensors. However, a miniature amperometric sensor base on Bi{sub 2}O{sub 3} was demonstrated in this program, and it is now seen that this latter sensor is far superior to the originally proposed Nernst sensor. 6 refs., 24 figs.

Arenz, R.W.

1991-10-07

8

Evolution and physiology of neural oxygen sensing.  

PubMed

Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O2 levels. Amongst other important factors, the increase in atmospheric O2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation of O2, e.g., the respiratory and cardiovascular systems of vertebrates. Global variations of O2 levels in post-Cambrian periods have also been correlated with evolutionary changes in animal physiology, especially cardiorespiratory function. Oxygen transportation systems are, in our view, ultimately controlled by the brain related mechanisms, which senses changes in O2 availability and regulates autonomic and respiratory responses that ensure the survival of the organism in the face of hypoxic challenges. In vertebrates, the major sensorial system for oxygen sensing and responding to hypoxia is the peripheral chemoreflex neuronal pathways, which includes the oxygen chemosensitive glomus cells and several brainstem regions involved in the autonomic regulation of the cardiovascular system and respiratory control. In this review we discuss the concept that regulating O2 homeostasis was one of the primordial roles of the nervous system. We also review the physiology of the peripheral chemoreflex, focusing on the integrative repercussions of chemoreflex activation and the evolutionary importance of this system, which is essential for the survival of complex organisms such as vertebrates. The contribution of hypoxia and peripheral chemoreflex for the development of diseases associated to the cardiovascular and respiratory systems is also discussed in an evolutionary context. PMID:25161625

Costa, Kauê M; Accorsi-Mendonça, Daniela; Moraes, Davi J A; Machado, Benedito H

2014-01-01

9

Superhydrophobic porous surfaces: dissolved oxygen sensing.  

PubMed

Porous polymer films are necessary for dissolved gas sensor applications that combine high sensitivity with selectivity. This report describes a greatly enhanced dissolved oxygen sensor system consisting of amphiphilic acrylamide-based polymers: poly(N-(1H, 1H-pentadecafluorooctyl)-methacrylamide) (pC7F15MAA) and poly(N-dodecylacrylamide-co-5- [4-(2-methacryloyloxyethoxy-carbonyl)phenyl]-10,15,20-triphenylporphinato platinum(II)) (p(DDA/PtTPP)). The nanoparticle formation capability ensures both superhydrophobicity with a water contact angle greater than 160° and gas permeability so that molecular oxygen enters the film from water. The film was prepared by casting a mixed solution of pC7F15MAA and p(DDA/PtTPP) with AK-225 and acetic acid onto a solid substrate. The film has a porous structure comprising nanoparticle assemblies with diameters of several hundred nanometers. The film shows exceptional performance as the oxygen sensitivity reaches 126: the intensity ratio at two oxygen concentrations (I0/I40) respectively corresponding to dissolved oxygen concentration 0 and 40 (mg L(-1)). Understanding and controlling porous nanostructures are expected to provide opportunities for making selective penetration/separation of molecules occurring at the superhydrophobic surface. PMID:25659178

Gao, Yu; Chen, Tao; Yamamoto, Shunsuke; Miyashita, Tokuji; Mitsuishi, Masaya

2015-02-18

10

Multifunctional mesoporous nanocomposites with magnetic, optical, and sensing features: synthesis, characterization, and their oxygen-sensing performance.  

PubMed

In this paper, the fabrication, characterization, and application in oxygen sensing are reported for a novel multifunctional nanomaterial of [Ru(bpy)(2)phen-MMS] (bpy, 2,2'-bipyridyl; phen, phenathrolin) which was simply prepared by covalently grafting the ruthenium(II) polypyridyl compounds into the channels of magnetic mesoporous silica nanocomposites (MMS). Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N(2) adsorption-desorption, a superconducting quantum interference device, UV-vis spectroscopy, and photoluminescence spectra were used to characterize the samples. The well-designed multifunctional nanocomposites show superparamagnetic behavior and ordered mesoporous characteristics and exhibit a strong red-orange metal-to-ligand charge transfer emission. In addition, the obtained nanocomposites give high performance in oxygen sensing with high sensitivity (I(0)/I(100) = 5.2), good Stern-Volmer characteristics (R(2) = 0.9995), and short response/recovery times (t? = 6 s and t? = 12 s). The magnetic, mesoporous, luminescent, and oxygen-sensing properties of this multifunctional nanostructure make it hold great promise as a novel multifunctional oxygen-sensing system for chemical/biosensor. PMID:23286606

Wang, Yanyan; Li, Bin; Zhang, Liming; Song, Hang

2013-01-29

11

Development of polymeric nanoprobes with improved lifetime dynamic range and stability for intracellular oxygen sensing.  

PubMed

A class of core-shell nanoparticles possessing a layer of biocompatible shell and hydrophobic core with embedded oxygen-sensitive platinum-porphyrin (PtTFPP) dyes is developed via a radical-initiated microemulsion co-polymerization strategy. The influences of host matrices and the PtTFPP incorporation manner on the photophysical properties and the oxygen-sensing performance of the nanoparticles are investigated. Self-loading capability with cells and intracellular-oxygen-sensing ability of the as-prepared nanoparticle probes in the range 0%-20% oxygen concentration are confirmed. Polymeric nanoparticles with optimized formats are characterized by their relatively small diameter (<50 nm), core-shell structures with biocompatible shells, covalent-attachment-imparted leak-free construction, improved lifetime dynamic range (up to 44 ?s), excellent storage stability and photostability, and facile cell uptake. The nanoparticles' small sensor diameter and core-shell structure with biocompatible shell make them suitable for intracellular detection applications. For intracellular detection applications, the leak-free feature of the as-prepared nanoparticle sensor effectively minimizes potential chemical interferences and cytotoxicity. As a salient feature, improved lifetime dynamic range of the sensor is expected to enable precise oxygen detection and control in specific practical applications in stem-cell biology and medical research. Such a feature-packed nanoparticle oxygen sensor may find applications in precise oxygen-level mapping of living cells and tissue. PMID:23519925

Liu, Heng; Yang, Hui; Hao, Xian; Xu, Haijiao; Lv, Yi; Xiao, Debao; Wang, Hongda; Tian, Zhiyuan

2013-08-12

12

Ceramide Mediates Acute Oxygen Sensing in Vascular Tissues  

PubMed Central

Abstract Aims: A variety of vessels, such as resistance pulmonary arteries (PA) and fetoplacental arteries and the ductus arteriosus (DA) are specialized in sensing and responding to changes in oxygen tension. Despite opposite stimuli, normoxic DA contraction and hypoxic fetoplacental and PA vasoconstriction share some mechanistic features. Activation of neutral sphingomyelinase (nSMase) and subsequent ceramide production has been involved in hypoxic pulmonary vasoconstriction (HPV). Herein we aimed to study the possible role of nSMase-derived ceramide as a common factor in the acute oxygen-sensing function of specialized vascular tissues. Results: The nSMase inhibitor GW4869 and an anticeramide antibody reduced the hypoxic vasoconstriction in chicken PA and chorioallantoic arteries (CA) and the normoxic contraction of chicken DA. Incubation with interference RNA targeted to SMPD3 also inhibited HPV. Moreover, ceramide and reactive oxygen species production were increased by hypoxia in PA and by normoxia in DA. Either bacterial sphingomyelinase or ceramide mimicked the contractile responses of hypoxia in PA and CA and those of normoxia in the DA. Furthermore, ceramide inhibited voltage-gated potassium currents present in smooth muscle cells from PA and DA. Finally, the role of nSMase in acute oxygen sensing was also observed in human PA and DA. Innovation: These data provide evidence for the proposal that nSMase-derived ceramide is a critical player in acute oxygen-sensing in specialized vascular tissues. Conclusion: Our results indicate that an increase in ceramide generation is involved in the vasoconstrictor responses induced by two opposite stimuli, such as hypoxia (in PA and CA) and normoxia (in DA). Antioxid. Redox Signal. 20, 1–14. PMID:23725018

Moreno, Laura; Moral-Sanz, Javier; Morales-Cano, Daniel; Barreira, Bianca; Moreno, Enrique; Ferrarini, Alessia; Pandolfi, Rachele; Ruperez, Francisco J.; Cortijo, Julio; Sanchez-Luna, Manuel; Villamor, Eduardo; Perez-Vizcaino, Francisco

2014-01-01

13

Two–Photon Oxygen Sensing with Quantum Dot–Porphyrin Conjugates  

PubMed Central

Supramolecular assemblies of a quantum dot (QD) associated to palladium(II) porphyrins have been developed to detect oxygen (pO2) in organic solvents. Palladium porphyrins are sensitive in the 0–160 torr range, making them ideal phosphors for in vivo biological oxygen quantification. Porphyrins with meso pyridyl substituents bind to the surface of the QD to produce self–assembled nanosensors. Appreciable overlap between QD emission and porphyrin absorption features results in efficient Förster resonance energy transfer (FRET) for signal transduction in these sensors. The QD serves as a photon antenna, enhancing porphyrin emission under both one– and two–photon excitation, demonstrating that QD–palladium porphyrin conjugates may be used for oxygen sensing over physiological oxygen ranges. PMID:23978247

Lemon, Christopher M.; Karnas, Elizabeth; Bawendi, Moungi G.; Nocera, Daniel G.

2013-01-01

14

Mechanisms of oxygen sensing in human trophoblast cells.  

PubMed

During pregnancy, changes in oxygen tension are essential for proper embryonic and placental development. Little is known about the mechanisms underlying mammalian cellular adaptations to changes in oxygen tension. Currently, we have explored putative mechanisms by which human trophoblast cells may sense oxygen. In order to investigate a role for hemoproteins in oxygen sensing, we cultured human villous explants of 5-8 weeks gestation under 20 per cent O(2) in the presence of either cobalt chloride or desferrioxamine, which interfere with the ability of iron (heme) to interact with oxygen. Treatment with these compounds mimicked hypoxia by stimulating the low oxygen effect on extravillous trophoblast outgrowth (EVT) and inducing HIF-1alpha expression, analogous to that observed in explants cultured at 3 per cent O(2). Addition of unhindered iron, in the form of iron chloride, to the treated-explants reversed the stimulatory effect on EVT outgrowth and HIF-1alpha expression. Subsequently, in order to probe into a mitochondrial role in trophoblast oxygen sensing, we cultured first trimester villous explants under 3 per cent O(2) in the presence of either diphenyleneiodonium or rotenone, known inhibitors of flavin-containing proteins. Treated-explants showed inhibition of the typical low oxygen-induced EVT outgrowth, when compared to untreated controls. Thus, this data supports a hypothesis that trophoblast cells may utilize mitochondria and/or hemoproteins as oxygen sensors to detect the critical changes in oxygen tension during pregnancy. PMID:11978060

De Marco, C S; Caniggia, I

2002-04-01

15

The Role of Redox Changes in Oxygen Sensing  

PubMed Central

The specialized oxygen-sensing tissues include the carotid body and arterial smooth muscle cells in the pulmonary artery (PA) and ductus arteriosus (DA). We discuss the evidence that changes in oxygen tension are sensed through changes in redox status. “Redox” changes imply the giving or accepting of electrons. This might occur through the direct tunneling of electrons from mitochondria or redox couples to an effector protein (eg. ion channel). Alternatively, the electron might be transferred through reactive oxygen species from mitochondria or an NADPH oxidase isoform. The PA's response to hypoxia and DA's response to normoxia result from reduction or oxidation, respectively. These opposing redox stimuli lead to K+ channel inhibition, membrane depolarization and an increase in cytosolic calcium and/or calcium sensitization that causes contraction. In the neuroendocrine cells (the type 1 cell of the carotid body, neuroepithelial body and adrenomedullary cells), the response is secretion. We examine the roles played by superoxide anion, hydrogen peroxide and the anti-oxidant enzymes in the signaling of oxygen tensions. PMID:20801237

Weir, E. Kenneth; Archer, Stephen L.

2010-01-01

16

Spatiotemporal oxygen sensing using dual emissive boron dye-polylactide nanofibers.  

PubMed

Oxygenation in tissue scaffolds continues to be a limiting factor in regenerative medicine despite efforts to induce neovascularization or to use oxygen-generating materials. Unfortunately, many established methods to measure oxygen concentration, such as using electrodes, require mechanical disturbance of the tissue structure. To address the need for scaffold-based oxygen concentration monitoring, a single-component, self-referenced oxygen sensor was made into nanofibers. Electrospinning process parameters were tuned to produce a biomaterial scaffold with specific morphological features. The ratio of an oxygen sensitive phosphorescence signal to an oxygen insensitive fluorescence signal was calculated at each image pixel to determine an oxygenation value. A single component boron dye-polymer conjugate was chosen for additional investigation due to improved resistance to degradation in aqueous media compared to a boron dye polymer blend. Standardization curves show that in fully supplemented media, the fibers are responsive to dissolved oxygen concentrations less than 15 ppm. Spatial (millimeters) and temporal (minutes) ratiometric gradients were observed in vitro radiating outward from the center of a dense adherent cell grouping on scaffolds. Sensor activation in ischemia and cell transplant models in vivo show oxygenation decreases on the scale of minutes. The nanofiber construct offers a robust approach to biomaterial scaffold oxygen sensing. PMID:25426706

Bowers, Daniel T; Tanes, Michael L; Das, Anusuya; Lin, Yong; Keane, Nicole A; Neal, Rebekah A; Ogle, Molly E; Brayman, Kenneth L; Fraser, Cassandra L; Botchwey, Edward A

2014-12-23

17

Oxygen Sensing Neurons and Neuropeptides Regulate Survival after Anoxia in Developing C. elegans  

PubMed Central

Hypoxic brain injury remains a major source of neurodevelopmental impairment for both term and preterm infants. The perinatal period is a time of rapid transition in oxygen environments and developmental resetting of oxygen sensing. The relationship between neural oxygen sensing ability and hypoxic injury has not been studied. The oxygen sensing circuitry in the model organism C. elegans is well understood. We leveraged this information to investigate the effects of impairments in oxygen sensing on survival after anoxia. There was a significant survival advantage in developing worms specifically unable to sense oxygen shifts below their preferred physiologic range via genetic ablation of BAG neurons, which appear important for conferring sensitivity to anoxia. Oxygen sensing that is mediated through guanylate cyclases (gcy-31, 33, 35) is unlikely to be involved in conferring this sensitivity. Additionally, animals unable to process or elaborate neuropeptides displayed a survival advantage after anoxia. Based on these data, we hypothesized that elaboration of neuropeptides by BAG neurons sensitized animals to anoxia, but further experiments indicate that this is unlikely to be true. Instead, it seems that neuropeptides and signaling from oxygen sensing neurons operate through independent mechanisms, each conferring sensitivity to anoxia in wild type animals. PMID:24967811

Flibotte, John J.; Jablonski, Angela M.; Kalb, Robert G.

2014-01-01

18

Dissolved Oxygen Sensing in a Flow Stream using Molybdenum Chloride Optical Indicators  

E-print Network

Dissolved Oxygen Sensing in a Flow Stream using Molybdenum Chloride Optical Indicators Reza Loloee1@msu.edu Abstract--Dissolved oxygen concentration is considered the most important water quality variable in fish culture. Reliable and continuous (24/7) oxygen monitoring of dissolved oxygen (DO) in the 1 ­ 11 mg

Ghosh, Ruby N.

19

Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads  

PubMed Central

Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems. PMID:23443975

Wang, Lin; Acosta, Miguel A.; Leach, Jennie B.; Carrier, Rebecca L.

2013-01-01

20

Oxygen Sensing for Industrial Safety — Evolution and New Approaches  

PubMed Central

The requirement for the detection of oxygen in industrial safety applications has historically been met by electrochemical technologies based on the consumption of metal anodes. Products using this approach have been technically and commercially successful for more than three decades. However, a combination of new requirements is driving the development of alternative approaches offering fresh opportunities and challenges. This paper reviews some key aspects in the evolution of consumable anode products and highlights recent developments in alternative technologies aimed at meeting current and anticipated future needs in this important application. PMID:24681673

Willett, Martin

2014-01-01

21

Phosphorescent Platinum(II) and Palladium(II) Complexes with Azatetrabenzoporphyrins—New Red Laser Diode-Compatible Indicators for Optical Oxygen Sensing  

PubMed Central

A new class of oxygen indicators is described. Platinum(II) and palladium(II) complexes of azatetrabenzoporphyrins occupy an intermediate position between tetrabenzoporphyrins and phthalocyanines and combine features of both. The new dyes are excitable in the red part of the spectrum and possess strong room-temperature NIR phosphorescence. Other features include excellent spectral compatibility with the red laser diodes and 632.8 nm line of He?Ne laser, excellent photostability, and significantly shorter decay times than for the respective meso-tetraphenyltetrabenzoporphyrins. Applicability of the complexes for optical oxygen sensing is demonstrated. PMID:20186289

2010-01-01

22

Near-infrared fluorescence: application to in vivo molecular imaging.  

PubMed

Molecular imaging often relies on the use of targeted and activatable reporters to quantitate and visualize targets, biological processes, and cells in vivo. The use of optical probes with near-infrared fluorescence allows for improved photon penetration through tissue and minimizes the effects of tissue autofluorescence. There are several parameters that define the effectiveness of imaging agents in vivo. These factors include probe targeting, activation, pharmacokinetics, biocompatibility, and photophysics. Recent advances in our understanding of these variables as they pertain to the application of optical reporters for in vivo imaging are discussed in this review. PMID:19879798

Hilderbrand, Scott A; Weissleder, Ralph

2010-02-01

23

Investigation of Genetic Disturbances in Oxygen Sensing and Erythropoietin Signaling Pathways in Cases of Idiopathic Erythrocytosis  

PubMed Central

Background. Idiopathic erythrocytosis is the term reserved for cases with unexplained origins of abnormally increased hemoglobin after initial investigation. Extensive molecular investigation of genes associated with oxygen sensing and erythropoietin signaling pathways, in those cases, usually involves sequencing all of their exons and it may be time consuming. Aim. To perform a strategy for molecular investigation of patients with idiopathic erythrocytosis regarding oxygen sensing and erythropoietin signaling pathways. Methods. Samples of patients with idiopathic erythrocytosis were evaluated for the EPOR, VHL, PHD2, and HIF-2? genes using bidirectional sequencing of their hotspots. Results. One case was associated with HIF-2? mutation. Sequencing did not identify any pathogenic mutation in 4 of 5 cases studied in any of the studied genes. Three known nonpathogenic polymorphisms were found (VHL p.P25L, rs35460768; HIF-2? p.N636N, rs35606117; HIF-2? p.P579P, rs184760160). Conclusion. Extensive molecular investigation of cases considered as idiopathic erythrocytosis does not frequently change the treatment of the patient. However, we propose a complementary molecular investigation of those cases comprising genes associated with erythrocytosis phenotype to meet both academic and genetic counseling purposes. PMID:24363938

Dinardo, Carla Luana; Santos, Paulo Caleb Junior Lima; Schettert, Isolmar Tadeu; Soares, Renata Alonso Gadi; Krieger, Jose Eduardo; Pereira, Alexandre Costa

2013-01-01

24

The human carotid body transcriptome with focus on oxygen sensing and inflammation – a comparative analysis  

PubMed Central

The carotid body (CB) is the key oxygen sensing organ. While the expression of CB specific genes is relatively well studied in animals, corresponding data for the human CB are missing. In this study we used five surgically removed human CBs to characterize the CB transcriptome with microarray and PCR analyses, and compared the results with mice data. In silico approaches demonstrated a unique gene expression profile of the human and mouse CB transcriptomes and an unexpected upregulation of both human and mouse CB genes involved in the inflammatory response compared to brain and adrenal gland data. Human CBs express most of the genes previously proposed to be involved in oxygen sensing and signalling based on animal studies, including NOX2, AMPK, CSE and oxygen sensitive K+ channels. In the TASK subfamily of K+ channels, TASK-1 is expressed in human CBs, while TASK-3 and TASK-5 are absent, although we demonstrated both TASK-1 and TASK-3 in one of the mouse reference strains. Maxi-K was expressed exclusively as the spliced variant ZERO in the human CB. In summary, the human CB transcriptome shares important features with the mouse CB, but also differs significantly in the expression of a number of CB chemosensory genes. This study provides key information for future functional investigations on the human carotid body. PMID:22615433

Mkrtchian, Souren; Kåhlin, Jessica; Ebberyd, Anette; Gonzalez, Constancio; Sanchez, Diego; Balbir, Alexander; Kostuk, Eric W; Shirahata, Machiko; Fagerlund, Malin Jonsson; Eriksson, Lars I

2012-01-01

25

Study on an oxygen sensing rhenium(I) complex with enlarged sensing/active area: fabrication, photophysical parameters and molecular oxygen sensing performance.  

PubMed

In this paper, we synthesize a novel 1,10-phenanthroline-derived (Phen-derived) diamine ligand of benzo[f][1,10]phenanthroline-6,7-dicarbonitrile (Phen-CN) with enlarged conjugation planar and its corresponding Re(I) complex of Re(CO)3Cl(Phen-CN), hoping to achieve an optical sensor owing large sensing/active area. Its geometric and electronic structures are investigated, which suggests that the effective sensing/active area of Re(CO)3Cl(Phen-CN) is enlarged by the successful formation of conjugation planar. The promising photophysical parameters of Re(CO)3Cl(Phen-CN), including large sensing/active area and long excited state lifetime, make it a potential probe for oxygen detection. By doping Re(CO)3Cl(Phen-CN) into a polymer matrix of poly(vinylpyrrolidone), oxygen sensing performances of the resulted composite materials are investigated. Finally, a high sensitivity of 17.1 is realized, with short response/recovery time of 9s/32s. PMID:24412790

Xu, Guiying; Lu, Mang; Huang, Can; Wang, Yaoqiong; Ge, Shuping

2014-04-01

26

Silicon-on-glass pore network micromodels with oxygen-sensing fluorophore films for chemical imaging and defined spatial structure  

SciTech Connect

Pore network microfluidic models were fabricated by a silicon-on-glass technique that provides the precision advantage of dry etched silicon while creating a structure that is transparent across all microfluidic channels and pores, and can be imaged from either side. A silicon layer is bonded to an underlying borosilicate glass substrate and thinned to the desired height of the microfluidic channels and pores. The silicon is then patterned and through-etched by deep reactive ion etching (DRIE), with the underlying glass serving as an etch stop. After bonding on a transparent glass cover plate, one obtains a micromodel in oxygen impermeable materials with water wet surfaces where the microfluidic channels are transparent and structural elements such as the pillars creating the pore network are opaque. The micromodel can be imaged from either side. The advantageous features of this approach in a chemical imaging application are demonstrated by incorporating a Pt porphyrin fluorophore in a PDMS film serving as the oxygen sensing layer and a bonding surface, or in a polystyrene film coated with a PDMS layer for bonding. The sensing of a dissolved oxygen gradient was demonstrated using fluorescence lifetime imaging, and it is shown that different matrix polymers lead to optimal use in different ranges dissolved oxygen concentration. Imaging with the opaque pillars in between the observation direction and the continuous fluorophore film yields images that retain spatial information in the sensor image.

Grate, Jay W.; Kelly, Ryan T.; Suter, Jonathan D.; Anheier, Norman C.

2012-11-21

27

Theory and in Vivo Application of Electroporative Gene Delivery  

Microsoft Academic Search

Efficient and safe methods for delivering exogenous genetic material into tissues must be developed before the clinical potential of gene therapy will be realized. Recently, in vivo electroporation has emerged as a leading technology for developing nonviral gene therapies and nucleic acid vaccines (NAV). Electroporation (EP) involves the application of pulsed electric fields to cells to enhance cell permeability, resulting

Stella Somiari; Jill Glasspool-Malone; Joseph J. Drabick; Richard A. Gilbert; Richard Heller; Mark J. Jaroszeski; Robert W. Malone

2000-01-01

28

Emerging novel functions of the oxygen-sensing prolyl hydroxylase domain enzymes.  

PubMed

Oxygen-sensing prolyl hydroxylase domain enzymes (PHDs) target hypoxia-inducible factor (HIF)-? subunits for proteasomal degradation in normoxia through hydroxylation. Recently, novel mechanisms of PHD activation and function have been unveiled. Interestingly, PHD3 can unexpectedly amplify HIF signaling through hydroxylation of the glycolytic enzyme pyruvate kinase (PK) muscle isoform 2 (PKM2). Recent studies have also yielded insight into HIF-independent PHD functions, including the control of ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor trafficking in synaptic transmission and the activation of transient receptor potential cation channel member A1 (TRPA1) ion channels by oxygen levels in sensory nerves. Finally, PHD activation has been shown to involve the iron chaperoning function of poly(rC) binding protein (PCBP)1 and the (R)-enantiomer of 2-hydroxyglutarate (2-HG). The intersection of these regulatory pathways and interactions highlight the complexity of PHD regulation and function. PMID:23200187

Wong, Brian W; Kuchnio, Anna; Bruning, Ulrike; Carmeliet, Peter

2013-01-01

29

In vivo distribution and ex vivo permeation of cyclosporine A prodrug aqueous formulations for ocular application.  

PubMed

Cyclosporine A is a poorly water-soluble, immunosuppressive drug used to treat a variety of ocular diseases. Its limited solubility makes challenging the development of a cyclosporine A-based eye drop for ocular topical application. Based on the prodrug strategy, the practically insoluble cyclosporine A was converted into a freely soluble prodrug. Such a water-soluble prodrug made it possible to develop water-based concentrated eye drops. The prodrug formulations were tested for their ex vivo permeation and in vivo distribution at three concentrations (equivalent to 0.05%, 0.50% and 2.00% w/v cyclosporine A). The ex vivo permeation experiments were performed on corneal and conjunctival epithelia. The in vivo distribution evaluated the total cyclosporine A present in the ocular structures as well as in serum, spleen and cervical lymphatic ganglions. Each prodrug formulation was compared to conventionally used cyclosporine A eye drops at an equivalent concentration. The experimental results showed that the tested eye drops behaved differently. The prodrug formulation was characterized by the following: i) preferential conjunctival penetration, ii) an interesting capacity to create large tissue deposits and iii) a lower risk of systemic complications and immunosuppression. The prodrug aqueous eye drop was demonstrated to be a patient-friendly option for the treatment of ocular diseases requiring high ocular levels of cyclosporine A, pushing the boundaries of the current therapeutic arsenal. PMID:23648835

Rodriguez-Aller, Marta; Guillarme, Davy; El Sanharawi, Mohamed; Behar-Cohen, Francine; Veuthey, Jean-Luc; Gurny, Robert

2013-08-28

30

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.  

Code of Federal Regulations, 2010 CFR

...culture media for human ex vivo tissue and cell culture processing applications. 876...culture media for human ex vivo tissue and cell culture processing applications. (a...culture media for human ex vivo tissue and cell culture processing applications...

2010-04-01

31

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.  

Code of Federal Regulations, 2011 CFR

...culture media for human ex vivo tissue and cell culture processing applications. 876...culture media for human ex vivo tissue and cell culture processing applications. (a...culture media for human ex vivo tissue and cell culture processing applications...

2011-04-01

32

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.  

Code of Federal Regulations, 2013 CFR

...culture media for human ex vivo tissue and cell culture processing applications. 876...culture media for human ex vivo tissue and cell culture processing applications. (a...culture media for human ex vivo tissue and cell culture processing applications...

2013-04-01

33

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.  

Code of Federal Regulations, 2012 CFR

...culture media for human ex vivo tissue and cell culture processing applications. 876...culture media for human ex vivo tissue and cell culture processing applications. (a...culture media for human ex vivo tissue and cell culture processing applications...

2012-04-01

34

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.  

Code of Federal Regulations, 2014 CFR

...culture media for human ex vivo tissue and cell culture processing applications. 876...culture media for human ex vivo tissue and cell culture processing applications. (a...culture media for human ex vivo tissue and cell culture processing applications...

2014-04-01

35

Cellular Oxygen Sensing: Crystal Structure of Hypoxia-Inducible Factor Prolyl Hydroxylase (PHD2)  

SciTech Connect

Cellular and physiological responses to changes in dioxygen levels in metazoans are mediated via the posttranslational oxidation of hypoxia-inducible transcription factor (HIF). Hydroxylation of conserved prolyl residues in the HIF-{alpha} subunit, catalyzed by HIF prolyl-hydroxylases (PHDs), signals for its proteasomal degradation. The requirement of the PHDs for dioxygen links changes in dioxygen levels with the transcriptional regulation of the gene array that enables the cellular response to chronic hypoxia; the PHDs thus act as an oxygen-sensing component of the HIF system, and their inhibition mimics the hypoxic response. We describe crystal structures of the catalytic domain of human PHD2, an important prolyl-4-hydroxylase in the human hypoxic response in normal cells, in complex with Fe(II) and an inhibitor to 1.7 Angstroms resolution. PHD2 crystallizes as a homotrimer and contains a double-stranded {beta}-helix core fold common to the Fe(II) and 2-oxoglutarate-dependant dioxygenase family, the residues of which are well conserved in the three human PHD enzymes (PHD 1-3). The structure provides insights into the hypoxic response, helps to rationalize a clinically observed mutation leading to familial erythrocytosis, and will aid in the design of PHD selective inhibitors for the treatment of anemia and ischemic disease.

McDonough,M.; Li, V.; Flashman, E.; Chowdhury, R.; Mohr, C.; Lienard, B.; Zondlo, J.; Oldham, N.; Clifton, I.; et al.

2006-01-01

36

Thickness Dependency of Thin Film Samaria Doped Ceria for Oxygen Sensing  

SciTech Connect

High temperature oxygen sensors are widely used for exhaust gas monitoring in automobiles. This particular study explores the use of thin film single crystalline samaria doped ceria as the oxygen sensing material. Desired signal to noise ratio can be achieved in a material system with high conductivity. From previous studies it is established that 6 atomic percent samarium doping is the optimum concentration for thin film samaria doped ceria to achieve high ionic conductivity. In this study, the conductivity of the 6 atomic percent samaria doped ceria thin film is measured as a function of the sensing film thickness. Hysteresis and dynamic response of this sensing platform is tested for a range of oxygen pressures from 0.001 Torr to 100 Torr for temperatures above 673 K. An attempt has been made to understand the physics behind the thickness dependent conductivity behavior of this sensing platform by developing a hypothetical operating model and through COMSOL simulations. This study can be used to identify the parameters required to construct a fast, reliable and compact high temperature oxygen sensor.

Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Jiang, Weilin; Varga, Tamas; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

2011-01-01

37

Engineering the oxygen sensing regulation results in an enhanced recombinant human hemoglobin production by Saccharomyces cerevisiae.  

PubMed

Efficient production of appropriate oxygen carriers for transfusions (blood substitutes or artificial blood) has been pursued for many decades, and to date several strategies have been used, from synthetic polymers to cell-free hemoglobin carriers. The recent advances in the field of metabolic engineering also allowed the generation of different genetically modified organisms for the production of recombinant human hemoglobin. Several studies have showed very promising results using the bacterium Escherichia coli as a production platform, reporting hemoglobin titers above 5% of the total cell protein content. However, there are still certain limitations regarding the protein stability and functionality of the recombinant hemoglobin produced in bacterial systems. In order to overcome these limitations, yeast systems have been proposed as the eukaryal alternative. We recently reported the generation of a set of plasmids to produce functional human hemoglobin in Saccharomyces cerevisiae, with final titers of active hemoglobin exceeding 4% of the total cell protein. In this study, we propose a strategy for further engineering S. cerevisiae by altering the oxygen sensing pathway by deleting the transcription factor HAP1, which resulted in an increase of the final recombinant active hemoglobin titer exceeding 7% of the total cellular protein. Biotechnol. Bioeng. 2015;112: 181-188. © 2014 Wiley Periodicals, Inc. PMID:25082441

Martínez, José L; Liu, Lifang; Petranovic, Dina; Nielsen, Jens

2015-01-01

38

In vivo Coherent Raman Imaging for Neuroscience Applications  

NASA Astrophysics Data System (ADS)

The use of coherent Raman imaging is described for applications in neuroscience. Myelin imaging of the spinal cord can be performed with Raman imaging through the use of the vibration in carbon-hydrogen bonds, dominant in lipids. First, we demonstrate in vivo histomorphometry in live animal for characterization of myelin-related nervous system pathologies. This is used to characterize spinal cord health during multiple sclerosis. Second, Raman spectroscopy of tissue is discussed. We discuss the challenges that live animal imaging brings, together with important aspects of coherent Raman imaging in tissue.

Cote, Daniel

2010-08-01

39

Synthesis, processing and characterization of calcia-stabilized zirconia solid electrolytes for oxygen sensing applications  

SciTech Connect

Precursor powders of calcia-stabilized zirconia (CSZ) solid electrolytes have been synthesized by a sol-gel method. The phase evolution of the precursor powders after thermal treatments at different temperatures were analysized by X-ray diffraction technique. Disc-shaped sensor elements were fabricated via uniaxial pressing of the calcined powders and subsequently sintered at 1650 deg. C. Scanning electron microscopy (SEM) was used to analyze the microstructure of the sintered pellets. Platinum electrodes were applied to the sintered elements to produce potentiometric/electrochemical gas sensors. The electrical response of the gas sensors to oxygen and the complex impedance of the sensors in air were measured at various temperatures. Impedance analyses indicate that the sensor cell with 15 mol% CaO has much lower resistance (the sum of bulk and grain-boundary resistance) than the sensor cell with 22 mol% CaO. This is also reflected by the EMF responses of both sensor cells to various oxygen concentrations in the testing gas. The EMF deviation from the theoretical value of the CSZ sensor cell with 22 mol% CaO was larger than that of the CSZ sensor cell with 15 mol% CaO. The corrrelations between material compositions, microstructures of the sintered pellets and the electrical properties of the sensors are discussed.

Zhou Minghua [Materials Technology Laboratory, Natural Resources Canada, 3484 Limebank Road, Ottawa, Ont., K1A 0E4 (Canada)]. E-mail: mzhou@nrcan.gc.ca; Ahmad, Aftab [Materials Technology Laboratory, Natural Resources Canada, 3484 Limebank Road, Ottawa, Ont., K1A 0E4 (Canada)

2006-04-13

40

Synthesis, processing and characterization of calcia-stabilized zirconia solid electrolytes for oxygen sensing applications  

Microsoft Academic Search

Precursor powders of calcia-stabilized zirconia (CSZ) solid electrolytes have been synthesized by a sol–gel method. The phase evolution of the precursor powders after thermal treatments at different temperatures were analysized by X-ray diffraction technique. Disc-shaped sensor elements were fabricated via uniaxial pressing of the calcined powders and subsequently sintered at 1650°C. Scanning electron microscopy (SEM) was used to analyze the

Minghua Zhou; Aftab Ahmad

2006-01-01

41

Influence of Intrinsic Hole Concentration on Oxygen Sensing Properties of Hot-Spot Based Eu{sub 1-x}Ca{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}}Ceramics  

SciTech Connect

We report oxygen sensing behavior of (Eu{sub 1-x}Ca{sub x})Ba{sub 2}Cu{sub 3}O{sub 7-{delta}}(x = 0.0,0.1) ceramics rods with formation of oxygen sensitive hot-spot upon application of external voltage. Oxygen response behavior of the x = 0.1 rod showed constant current plateau with increasing voltage and displayed better stability and reproducibility compared to x = 0 rod probably due to increased intrinsic hole concentration and reduction in activation energy as a result of Ca{sup 2+} substitution..

Yaacob, S. A.; Yahya, A. K.; Hassan, M.; Hasham, R. [School of Physics and Materials Sciences, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

2010-07-07

42

POLYMERSOMES: MULTI-FUNCTIONAL TOOLS FOR IN VIVO CANCER THERANOSTIC APPLICATIONS.  

E-print Network

??ABSTRACT POLYMERSOMES: MULTI-FUNCTIONAL TOOLS FOR IN VIVO CANCER THERANOSTIC APPLICATIONS Dalia Hope Levine Dr. Daniel A. Hammer Nanoparticles are currently being developed as delivery vehicles… (more)

Levine, Dalia H

2010-01-01

43

Engineered Biocompatible Nanoparticles for in Vivo Imaging Applications  

PubMed Central

Iron?platinum alloy nanoparticles (FePt NPs) are extremely promising candidates for the next generation of contrast agents for magnetic resonance (MR) diagnostic imaging and MR-guided interventions, including hyperthermic ablation of solid cancers. FePt has high Curie temperature, saturation magnetic moment, magneto-crystalline anisotropy, and chemical stability. We describe the synthesis and characterization of a family of biocompatible FePt NPs suitable for biomedical applications, showing and discussing that FePt NPs can exhibit low cytotoxicity. The importance of engineering the interface of strongly magnetic NPs using a coating allowing free aqueous permeation is demonstrated to be an essential parameter in the design of new generations of diagnostic and therapeutic MRI contrast agents. We report effective cell internalization of FePt NPs and demonstrate that they can be used for cellular imaging and in vivo MRI applications. This opens the way for several future applications of FePt NPs, including regenerative medicine and stem cell therapy in addition to enhanced MR diagnostic imaging. PMID:20919679

2010-01-01

44

In vitro - In vivo Correlation: From Theory to Applications  

Microsoft Academic Search

A key goal in pharmaceutical development of dosage forms is a good understanding of the in vitro and in vivo performance of the dosage forms. One of the challenges of biopharmaceutics research is correlating in vitro drug release information of various drug formulations to the in vivo drug profiles (IVIVC). Thus the need for a tool to reliably correlate in

Jaber Emami

45

Transesophageal ultrasound applicator for sector-based thermal ablation: First in vivo experiments  

E-print Network

Transesophageal ultrasound applicator for sector-based thermal ablation: First in vivo experiments: Ultrasound, thermal ablation, coagulation necrosis, intraductal therapy, sector- based, plane transducer modalities for therapeutic thermal ablation, ultrasound presents two major advantages. Ultrasound penetrates

Paris-Sud XI, Université de

46

An optical biopsy system with miniaturized Raman and spectral imaging probes; in vivo animal and ex vivo clinical application studies  

NASA Astrophysics Data System (ADS)

An optical biopsy system which equips miniaturized Raman probes, a miniaturized endoscope and a fluorescent image probe has been developed for in vivo studies of live experimental animals. The present report describes basic optical properties of the system and its application studies for in vivo cancer model animals and ex vivo human cancer tissues. It was developed two types of miniaturized Raman probes, micro Raman probe (MRP) made of optical fibers and ball lens hollow optical fiber Raman probe (BHRP) made of single hollow optical fiber (HOF) with a ball lens. The former has rather large working distance (WD), up to one millimeter. The latter has small WD (~300?m) which depends on the focal length of the ball lens. Use of multiple probes with different WD allows one to obtain detailed information of subsurface tissues in the totally noninvasive manner. The probe is enough narrow to be inserted into a biopsy needle (~19G), for observations of the lesion at deeper inside bodies. The miniaturized endoscope has been applied to observe progression of a stomach cancer in the same rat lesion. It was succeeded to visualize structure of non-stained cancer tissue in live model animals by the fluorescent image technique. The system was also applied to ex vivo studies of human breast and stomach cancers.

Sato, Hidetoshi; Suzuki, Toshiaki; Andriana, Bibin B.; Morita, Shin'ichi; Maruyama, Atsushi; Shinzawa, Hideyuki; Komachi, Yuichi; Kanai, Gen'ichi; Ura, Nobuo; Masutani, Koji; Matsuura, Yuji; Toi, Masakazu; Shimosegawa, Toru; Ozaki, Yukihiro

2009-02-01

47

Hematopoietic Stem Cells: Transcriptional Regulation, Ex Vivo Expansion and Clinical Application  

PubMed Central

Maintenance of ex vivo hematopoietic stem cells (HSC) pool and its differentiated progeny is regulated by complex network of transcriptional factors, cell cycle proteins, extracellular matrix, and their microenvironment through an orchestrated fashion. Strides have been made to understand the mechanisms regulating in vivo quiescence and proliferation of HSCs to develop strategies for ex vivo expansion. Ex vivo expansion of HSCs is important to procure sufficient number of stem cells and as easily available source for HSC transplants for patients suffering from hematological disorders and malignancies. Our lab has established a nanofiber-based ex vivo expansion strategy for HSCs, while preserving their stem cell characteristics. Ex vivo expanded cells were also found biologically functional in various disease models. However, the therapeutic potential of expanded stem cells at clinical level still needs to be verified. This review outlines transcriptional factors that regulate development of HSCs and their commitment, genes that regulate cell cycle status, studies that attempt to develop an effective and efficient protocol for ex vivo expansion of HSCs and application of HSC in various non-malignant and malignant disorders. Overall the goal of the current review is to deliver an understanding of factors that are critical in resolving the challenges that limit the expansion of HSCs in vivo and ex vivo. PMID:22082480

Aggarwal, R.; Lu, J.; Pompili, V.J.; Das, H.

2012-01-01

48

Somatic Pairing of Chromosome 19 in Renal Oncocytoma Is Associated with Deregulated ELGN2-Mediated Oxygen-Sensing Response  

PubMed Central

Chromosomal abnormalities, such as structural and numerical abnormalities, are a common occurrence in cancer. The close association of homologous chromosomes during interphase, a phenomenon termed somatic chromosome pairing, has been observed in cancerous cells, but the functional consequences of somatic pairing have not been established. Gene expression profiling studies revealed that somatic pairing of chromosome 19 is a recurrent chromosomal abnormality in renal oncocytoma, a neoplasia of the adult kidney. Somatic pairing was associated with significant disruption of gene expression within the paired regions and resulted in the deregulation of the prolyl-hydroxylase ELGN2, a key protein that regulates the oxygen-dependent degradation of hypoxia-inducible factor (HIF). Overexpression of ELGN2 in renal oncocytoma increased ubiquitin-mediated destruction of HIF and concomitantly suppressed the expression of several HIF-target genes, including the pro-death BNIP3L gene. The transcriptional changes that are associated with somatic pairing of chromosome 19 mimic the transcriptional changes that occur following DNA amplification. Therefore, in addition to numerical and structural chromosomal abnormalities, alterations in chromosomal spatial dynamics should be considered as genomic events that are associated with tumorigenesis. The identification of EGLN2 as a significantly deregulated gene that maps within the paired chromosome region directly implicates defects in the oxygen-sensing network to the biology of renal oncocytoma. PMID:18773095

Petillo, David; Westphal, Michael; Koelzer, Katherine; Metcalf, Julie L.; Zhang, Zhongfa; Matsuda, Daisuke; Dykema, Karl J.; Houseman, Heather L.; Kort, Eric J.; Furge, Laura L.; Kahnoski, Richard J.; Richard, Stéphane; Vieillefond, Annick; Swiatek, Pamela J.; Teh, Bin Tean; Ohh, Michael; Furge, Kyle A.

2008-01-01

49

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants  

SciTech Connect

A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of a molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. We have extensively characterized two fiber sensors at high temperature. We obtain quenching ratios between pure nitrogen and 21% oxygen as high as 3.9 x at 70 C. For the first sensor at 60 C we obtained a {+-} 1% variation in the quenching ratio over 6 cycles of measurement, and monitored the device performance over 23 days. We were able to operate the second sensor continuously for 14 hours at 70 C, and the sensor quenching ratio was stable to 5% over that time period. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

2006-01-01

50

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants  

SciTech Connect

A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we immobilized the potassium salt of a molybdenum cluster, K{sub 2}M{sub 6}Cl{sub 14}, in a sol-gel matrix and showed that the luminescence is stable after 54 hours at 200 C, but the quenching ratios were low and the films delaminated after thermal cycling due to densification of the matrix. Three new approaches to solve decreased quenching over time and delamination of films off fiber tips were investigated. In the first approach K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were incorporated into a TEOS based sol-gel. These gave enhanced quenching (6x), but delaminated. Our second approach was to use a commercial cyanoacrylate glue to immobilize the particles onto the tip of an optical fiber. This gave better adhesion and good quenching initially, but eventually the glue degraded upon heating. Our third approach was to use a 55% OtMOS/ TEOS sol-gel binder. Films based on this new sol-gel binder show high quenching ({approx}6x) and superior mechanical stability even after thermal cycling. Sensor measurements on an optical fiber containing K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were obtained from 100 to 25 C. The signal intensity in nitrogen was stable at 2.8 {+-} 0.2 nW, and the quenching ratio (ratio of signal in N{sub 2} vs. 21 % O{sub 2}) varied from 4.4 to 6.9X. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

2005-10-01

51

A Telemedicine Application to Schedule Temperature in an In Vivo Sensor Network for Cancer Treatment  

PubMed Central

Abstract Wireless communication has played a significant role in modern healthcare systems. However, the death toll from chronic diseases, such as cancer, continues to increase. Hyperthermia combined with radiotherapy and/or chemotherapy is a promising strategy for cancer treatment, and temperature control is critical for the success of this intervention. In vivo sensors are an emerging technology in healthcare. Thermal awareness has also received attention in in vivo sensor research. In this context, we have been motivated to use in vivo sensors to regulate the temperature changes in cancer cells during combined treatment. Limitations in existing in vivo thermal-aware routing algorithms motivated us to use the in vivo “lightweight rendezvous routing” approach. However, smartphone-driven telemedicine applications are proliferating to provide remote healthcare and collaborative consultation, required in combined therapies. In this context, we have proposed a telemedicine application where a smartphone not only regulates temperature scheduling in in vivo sensors, but also communicates with local or remote clinicians to maintain collaborative efforts for combined therapies against cancer. PMID:23234425

Kamal, Rossi; Lee, Seok-Geun

2012-01-01

52

Biocompatible PEGylated gold nanorods as colored contrast agents for targeted in vivo cancer applications  

NASA Astrophysics Data System (ADS)

In this contribution, we report the use of a PEGylated gold nanorods formulation as a colored dye for tumor labeling in vivo. We have demonstrated that the nanorod-targeted tumor site can be easily differentiated from the background tissues by the 'naked eye' without the need of sophisticated imaging instruments. In addition to tumor labeling, we have also performed in vivo toxicity and biodistribution studies of PEGylated gold nanorods in vivo by using BALB/c mice as the model. In vivo toxicity studies indicated no mortality or adverse effects or weight changes in BALB/c mice treated with PEGylated gold nanorods. This finding will provide useful guidelines in the future development of diagnostic probes for cancer diagnosis, optically guided tumor surgery, and lymph node mapping applications.

Kopwitthaya, Atcha; Yong, Ken-Tye; Hu, Rui; Roy, Indrajit; Ding, Hong; Vathy, Lisa A.; Bergey, Earl J.; Prasad, Paras N.

2010-08-01

53

Clinical applications of in vivo neutron-activation analysis  

SciTech Connect

In vivo neutron activation has opened a new era of both clinical diagnosis and therapy evaluation, and investigation into and modelling of body composition. The techniques are new, but it is already clear that considerable strides can be made in increasing accuracy and precision, increasing the number of elements susceptible to measurement, enhancing uniformity, and reducing the dose required for the measurement. The work presently underway will yield significant data on a variety of environmental contaminants such as Cd. Compositional studies are determining the level of vital constituents such as nitrogen and potassium in both normal subjects and in patients with a variety of metabolic disorders. Therapeutic programs can be assessed while in progress.

Cohn, S.H.

1982-01-01

54

Comparison of in vivo and ex vivo laser scanning microscopy and multiphoton tomography application for human and porcine skin imaging  

NASA Astrophysics Data System (ADS)

Two state-of-the-art microscopic optical methods, namely, confocal laser scanning microscopy in the fluorescence and reflectance regimes and multiphoton tomography in the autofluorescence and second harmonic generation regimes, are compared for porcine skin ex vivo and healthy human skin in vivo. All skin layers such as stratum corneum (SC), stratum spinosum (SS), stratum basale (SB), papillary dermis (PD) and reticular dermis (RD) as well as transition zones between these skin layers are measured noninvasively at a high resolution, using the above mentioned microscopic methods. In the case of confocal laser scanning microscopy (CLSM), measurements in the fluorescence regime were performed by using a fluorescent dye whose topical application on the surface is well suited for the investigation of superficial SC and characterisation of the skin barrier function. For investigations of deeply located skin layers, such as SS, SB and PD, the fluorescent dye must be injected into the skin, which markedly limits fluorescence measurements using CLSM. In the case of reflection CLSM measurements, the obtained results can be compared to the results of multiphoton tomography (MPT) for all skin layers excluding RD. CLSM cannot distinguish between dermal collagen and elastin measuring their superposition in the RD. By using MPT, it is possible to analyse the collagen and elastin structures separately, which is important for the investigation of anti-aging processes. The resolution of MPT is superior to CLSM. The advantages and limitations of both methods are discussed and the differences and similarities between human and porcine skin are highlighted.

Darvin, M. E.; Richter, H.; Zhu, Y. J.; Meinke, M. C.; Knorr, F.; Gonchukov, S. A.; Koenig, K.; Lademann, J.

2014-07-01

55

Stimuli-responsive photoacoustic nanoswitch for in vivo sensing applications.  

PubMed

Photoacoustic imaging provides high-resolution images at depths beyond the optical diffusion limit. To broaden its utility, there is need for molecular sensors capable of detecting environmental stimuli through alterations in photoacoustic signal. Photosynthetic organisms have evolved ingenious strategies to optimize light absorption through nanoscale ordered dye aggregation. Here, we use this concept to synthesize a stimuli-responsive nanoswitch with a large optical absorbance and sensing capabilities. Ordered dye aggregation between light-harvesting porphyrins was achieved through intercalation within thermoresponsive nanovesicles. This causes an absorbance red-shift of 74 nm and a 2.7-fold increase in absorptivity of the Qy-band, with concomitant changes in its photoacoustic spectrum. This spectral feature can be reversibly switched by exceeding a temperature threshold. Using this thermochromic property, we noninvasively determined a localized temperature change in vivo, relevant for monitoring thermal therapies of solid tumors. Similar strategies may be applied alongside photoacoustic imaging, to detect other stimuli such as pH and enzymatic activity. PMID:25046406

Ng, Kenneth K; Shakiba, Mojdeh; Huynh, Elizabeth; Weersink, Robert A; Roxin, Áron; Wilson, Brian C; Zheng, Gang

2014-08-26

56

Optogenetic tools for in vivo applications in neonatal mice  

NASA Astrophysics Data System (ADS)

Spontaneous neural activities exist early in development and their spatiotemporal patterns play important roles in the development of sensory maps such as maps of retinotopy in the visual system. We summarized different optogenetic tools, including transgenic mouse lines, viral-mediated transfection and electroporation methods to enable the expression of light-gated channelrhodopsin (ChR2) in retinal ganglion cells (RGCs) before the onset of vision. Patch-clamp and extracellular recording experiments verified that activities of ChR2-expressing cells were precisely manipulated by the patterns of optical stimuli. In chronic stimulation experiments, light-emitting diodes controlled the activity patterns of ChR2-expressing RGCs in vivo. Changes in the retinotopic map in Superior Colliculus (SC) were examined by quantifying the relative sizes of fluorescently labeled target zones. Our results revealed that various optogenetic and optical tools can manipulate retinal activities with precise temporal patterns. These techniques can be readily used in studying the development of the central nervous system of neonatal rodents.

Zhang, Yue; Qin, Nan; Diao, Yupu; Guan, Yangtai; Fan, Lu; Crair, Michael C.; Zhang, Jiayi

2012-10-01

57

Deep tissue fluorescence imaging and in vivo biological applications  

NASA Astrophysics Data System (ADS)

We describe a novel technical approach with enhanced fluorescence detection capabilities in two-photon microscopy that achieves deep tissue imaging, while maintaining micron resolution. Compared to conventional two-photon microscopy, greater imaging depth is achieved by more efficient harvesting of fluorescence photons propagating in multiple-scattering media. The system maintains the conventional two-photon microscopy scheme for excitation. However, for fluorescence collection the detection system harvests fluorescence photons directly from a wide area of the turbid sample. The detection scheme relies on a wide area detector, minimal optical components and an emission path bathed in a refractive-index-matching fluid that minimizes emission photon losses. This detection scheme proved to be very efficient, allowing us to obtain high resolution images at depths up to 3 mm. This technique was applied to in vivo imaging of the murine small intestine (SI) and colon. The challenge is to image normal and diseased tissue in the whole live animal, while maintaining high resolution imaging at millimeter depth. In Lgr5-GFP mice, we have been successful in imaging Lgr5-eGFP positive stem cells, present in SI and colon crypt bases.

Crosignani, Viera; Dvornikov, Alexander; Aguilar, Jose S.; Stringari, Chiara; Edwards, Robert; Mantulin, William W.; Gratton, Enrico

2012-11-01

58

Application of a practical method for the isocenter point in vivo dosimetry by a transit signal  

Microsoft Academic Search

This work reports the results of the application of a practical method to determine the in vivo dose at the isocenter point, Diso, of brain thorax and pelvic treatments using a transit signal St. The use of a stable detector for the measurement of the signal St (obtained by the x-ray beam transmitted through the patient) reduces many of the

Angelo Piermattei; Andrea Fidanzio; Luigi Azario; Luca Grimaldi; Guido D'Onofrio; Savino Cilla; Gerardina Stimato; Diego Gaudino; Sara Ramella; Rolando D'Angelillo; Francesco Cellini; Lucio Trodella; Aniello Russo; Luciano Iadanza; Sergio Zucca; Vincenzo Fusco; Nicola Di Napoli; Maria Antonietta Gambacorta; Mario Balducci; Numa Cellini; Francesco Deodato; Gabriella Macchia; Alessio G. Morganti

2007-01-01

59

A New Crosslinkable Oxygen Sensor Covalently Bonded into Poly(2-hydroxyethyl methacrylate)-CO-Polyacrylamide Thin Film for Dissolved Oxygen Sensing  

PubMed Central

A new oxygen sensor, compound 2, was synthesized through a chemical modification of a popularly used oxygen sensor of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP). The new sensor compound 2 possesses four crosslinkable methacrylate functional moieties, enabling it to be polymerized and crosslinked with other monomers for polymer sensing film (also called membrane) preparation. Using this characteristic, compound 2 was covalently bonded to hydrophilic poly(2-hydroxyethyl methacrylate)-co-polyacrylamide (referred to as PHEMA to simplify) and hydrophobic polystyrene (PS) films. To better understand the advantages and disadvantages of chemical crosslinking approaches and the influence of polymer matrices on sensing performance, PtTFPP was physically incorporated into the same PHEMA and PS matrices to compare. Response to dissolved oxygen (DO), leaching of the sensor molecules from their matrices, photostability of the sensors, and response time to DO changes were studied. It was concluded that the chemical crosslinking of the sensor compound 2 in polymer matrices: (i) alleviated the leaching problem of sensor molecules which usually occurred in the physically doped sensing systems and (ii) significantly improved sensors’ photostability. The PHEMA matrix was demonstrated to be more suitable for oxygen sensing than PS, because for the same sensor molecule, the oxygen sensitivity in PHEMA film was higher than that in PS and response time to DO change in the PHEMA film was faster than that in PS. It was the first time oxygen sensing films were successfully prepared using biocompatible hydrophilic PHEMA as a matrix, which does not allow leaching of the sensor molecules from the polymer matrix, has a faster response to DO changes than that of PS, and does not present cytotoxicity to human lung adenocarcinoma epithelial cells (A549). It is expected that the new sensor compound 2 and its similar compounds with chemically crosslinking characteristics can be widely applied to generate many interesting oxygen sensing materials for studying biological phenomena. PMID:20352057

Tian, Yanqing; Shumway, Bradley R.; Meldrum, Deirdre R.

2010-01-01

60

In vivo measurement of the frame-based application accuracy of the Neuromate neurosurgical robot.  

PubMed

OBJECT The application accuracy of the Neuromate neurosurgical robot has been validated in vitro but has not been evaluated in vivo for deep brain stimulation (DBS) electrode implantations. The authors conducted a study to evaluate this application accuracy in routine frame-based DBS procedures, with an independent system of measurement. METHODS The Euclidian distance was measured between the point theoretically targeted by the robot and the point actually reached, based on their respective stereotactic coordinates. The coordinates of the theoretical target were given by the robot's dedicated targeting software. The coordinates of the point actually reached were recalculated using the Stereoplan localizer system. This experiment was performed in vitro, with the frame fixed in the robot space without a patient, for 21 points spatially distributed. The in vivo accuracy was then measured in 30 basal ganglia targets in 17 consecutive patients undergoing DBS for movement disorders. RESULTS The mean in vitro application accuracy was 0.44 ± 0.23 mm. The maximal localization error was 1.0 mm. The mean (± SD) in vivo application accuracy was 0.86 ± 0.32 mm (?x = 0.37 ± 0.34 mm, ?y = 0.32 ± 0.24 mm, ?z = 0.58 ± 0.31 mm). The maximal error was 1.55 mm. CONCLUSIONS The in vivo application accuracy of the Neuromate neurosurgical robot, measured with a system independent from the robot, in frame-based DBS procedures was better than 1 mm. This accuracy is at least similar to the accuracy of stereotactic frame arms and is compatible with the accuracy required in DBS procedures. PMID:25361490

von Langsdorff, Daniel; Paquis, Philippe; Fontaine, Denys

2015-01-01

61

In vivo molecular imaging using nanomaterials: general in vivo characteristics of nano-sized reagents and applications for cancer diagnosis.  

PubMed

Nanoparticles present a new collection of contrast agents for the field of in vivo molecular imaging. This review focuses on promising molecular imaging probes for optical and magnetic resonance imaging based on four representative nanomaterial(s) platforms: quantum dots, upconversion phosphors, superparamagnetic iron oxides, and dendrimer-based agents. Quantum dots are extremely efficient fluorescent nanoparticles with size-tunable emission properties, enabling high sensitivity and greater depth penetration. Their heavy metal composition and long retention in the body, however, pose concerns for clinical translational applications. Upconversion phosphors generate excellent signal-to-background contrast because they emit light with higher energy than the excitation photons and autofluorescence signals. For MRI, iron oxide particles also generate excellent signal and have been used in liver imaging and for cell tracking studies. As they are metabolized through endogenous iron salvage pathways, they have already been introduced as clinical contrast agents. Lastly, dendrimers, a 'soft' nanoparticle, can be used as a structural basis for the attachment of small molecule imaging agents and/or targeting groups. This array of nanoparticles should offer insights into the uses and potentials of nanoparticles for the molecular imaging. PMID:20455640

Rosenblum, Lauren T; Kosaka, Nobuyuki; Mitsunaga, Makoto; Choyke, Peter L; Kobayashi, Hisataka

2010-10-01

62

In Vivo Application of Optogenetics for Neural Circuit Analysis Biomedical Engineering Department, Boston University, Boston, Massachusetts, United States  

E-print Network

In Vivo Application of Optogenetics for Neural Circuit Analysis Xue Han Biomedical Engineering Department, Boston University, Boston, Massachusetts, United States ABSTRACT: Optogenetics combines optical temporal precision, optogenetic tools have enabled new ways to probe the causal role of specific cells

Han, Xue

63

The application of dermal papillary rings in dermatology by in vivo confocal laser scanning microscopy  

NASA Astrophysics Data System (ADS)

Confocal laser scanning microscopy (CLSM) allows noninvasive visualization of human skin in vivo, without needing to fix or section the tissue. Melanocytes and pigmented keratinocytes at the level of the basal layer form bright dermal papillary rings which are readily amenable to identify in confocal images. Our purpose was to explore the role of dermal papillary rings in assessment of lesion location, the diagnosis, differential diagnosis of lesions and assessment of therapeutic efficacy by in vivo CLSM. Seventy-one patients were imaged with the VivaScope 1500 reflectance confocal microscope provided by Lucid, Inc. The results indicate that dermal papillary rings can assess the location of lesion; the application of dermal papillary rings can provide diagnostic support and differential diagnosis for vitiligo, nevus depigmentosus, tinea versicolor, halo nevus, common nevi, and assess the therapeutic efficacy of NBUVB phototherapy plus topical 0.1 percent tacrolimus ointment for vitiligo. In conclusion, our findings indicate that the dermal papillary rings play an important role in the assessment the location of lesion, diagnosis, differential diagnosis of lesions and assessment of therapeutic efficacy by in vivo CLSM. CLSM may be a promising tool for noninvasive examination in dermatology. However, larger studies are needed to expand the application of dermal papillary rings in dermatology.

Xiang, W. Z.; Xu, A. E.; Xu, J.; Bi, Z. G.; Shang, Y. B.; Ren, Q. S.

2010-08-01

64

Phosphorescent nanoparticles for quantitative measurements of oxygen profiles in vitro and in vivo  

PubMed Central

We present the development and characterization of nanoparticles loaded with a custom phosphor; we exploit these nanoparticles to perform quantitative measurements of the concentration of oxygen within three-dimensional (3-D) tissue cultures in vitro and blood vessels in vivo. We synthesized a customized ruthenium (Ru)-phosphor and incorporated it into polymeric nanoparticles via self-assembly. We demonstrate that the encapsulated phosphor is non-toxic with and without illumination. We evaluated two distinct modes of employing the phosphorescent nanoparticles for the measurement of concentrations of oxygen: 1) in vitro, in a 3-D microfluidic tumor model via ratiometric measurements of intensity with an oxygen-insensitive fluorophore as a reference, and 2) in vivo, in mouse vasculature using measurements of phosphorescence lifetime. With both methods, we demonstrated micrometer-scale resolution and absolute calibration to the dissolved oxygen concentration. Based on the ease and customizability of the synthesis of the nanoparticles and the flexibility of their application, these oxygen-sensing polymeric nanoparticles will find a natural home in a range of biological applications, benefiting studies of physiological as well as pathological processes in which oxygen availability and concentration play a critical role. PMID:22240511

Choi, Nak Won; Verbridge, Scott S.; Williams, Rebecca M.; Chen, Jin; Kim, Ju-Young; Schmehl, Russel; Farnum, Cornelia E.; Zipfel, Warren R.; Fischbach, Claudia; Stroock, Abraham D.

2012-01-01

65

Engineered nanocrystal technology: in-vivo fate, targeting and applications in drug delivery.  

PubMed

Formulation of nanocrystals is a robust approach which can improve delivery of poorly water soluble drugs, a challenge pharmaceutical industry has been facing since long. Large scale production of nanocrystals is done by techniques like precipitation, media milling and, high pressure homogenization. Application of appropriate stabilizers along with drying accords long term stability and commercial viability to nanocrystals. These can be administered through oral, parenteral, pulmonary, dermal and ocular routes showing their high therapeutic applicability. They serve to target drug molecules in specific regions through size manipulation and surface modification. This review dwells upon the in-vivo fate and varying applications in addition to the facets of drug nanocrystals stated above. PMID:24667572

Pawar, Vivek K; Singh, Yuvraj; Meher, Jaya Gopal; Gupta, Siddharth; Chourasia, Manish K

2014-06-10

66

In vitro and in vivo application of anti-cotinine antibody and cotinine-conjugated compounds  

PubMed Central

The combination of a high-affinity antibody to a hapten, and hapten-conjugated compounds, can provide an alternative to the direct chemical cross-linking of the antibody and compounds. An optimal hapten for in vitro use is one that is absent in biological systems. For in vivo applications, additional characteristics such as pharmacological safety and physiological inertness would be beneficial. Additionally, methods for cross-linking the hapten to various chemical compounds should be available. Cotinine, a major metabolite of nicotine, is considered advantageous in these aspects. A high-affinity anti-cotinine recombinant antibody has recently become available, and can be converted into various formats, including a bispecific antibody. The bispecific anti-cotinine antibody was successfully applied to immunoblot, enzyme immunoassay, immunoaffinity purification, and pre-targeted in vivo radioimmunoimaging. The anti-cotinine IgG molecule could be complexed with aptamers to form a novel affinity unit, and extended the in vivo half-life of aptamers, opening up the possibility of applying the same strategy to therapeutic peptides and chemical compounds. [BMB Reports 2014; 47(3): 130-134] PMID:24499668

Kim, Hyori; Yoon, Soomin; Chung, Junho

2014-01-01

67

Non invasive in vivo investigation of hepatobiliary structure and function in STII medaka (Oryzias latipes): methodology and applications  

PubMed Central

Background A novel transparent stock of medaka (Oryzias latipes; STII), recessive for all pigments found in chromatophores, permits transcutaneous imaging of internal organs and tissues in living individuals. Findings presented describe the development of methodologies for non invasive in vivo investigation in STII medaka, and the successful application of these methodologies to in vivo study of hepatobiliary structure, function, and xenobiotic response, in both 2 and 3 dimensions. Results Using brightfield, and widefield and confocal fluorescence microscopy, coupled with the in vivo application of fluorescent probes, structural and functional features of the hepatobiliary system, and xenobiotic induced toxicity, were imaged at the cellular level, with high resolution (< 1 ?m), in living individuals. The findings presented demonstrate; (1) phenotypic response to xenobiotic exposure can be investigated/imaged in vivo with high resolution (< 1 ?m), (2) hepatobiliary transport of solutes from blood to bile can be qualitatively and quantitatively studied/imaged in vivo, (3) hepatobiliary architecture in this lower vertebrate liver can be studied in 3 dimensions, and (4) non invasive in vivo imaging/description of hepatobiliary development in this model can be investigated. Conclusion The non-invasive in vivo methodologies described are a unique means by which to investigate biological structure, function and xenobiotic response with high resolution in STII medaka. In vivo methodologies also provide the future opportunity to integrate molecular mechanisms (e.g., genomic, proteomic) of disease and toxicity with phenotypic changes at the cellular and system levels of biological organization. While our focus has been the hepatobiliary system, other organ systems are equally amenable to in vivo study, and we consider the potential for discovery, within the context of in vivo investigation in STII medaka, as significant. PMID:18838008

Hardman, Ron C; Kullman, Seth W; Hinton, David E

2008-01-01

68

Polymer-based, flexible glutamate and lactate microsensors for in vivo applications.  

PubMed

We present a flexible microsensor, based on a polymer substrate, for multiparametric, electrochemical in vivo monitoring. The sensor strip with a microelectrode array at the tip was designed for insertion into tissue, for fast and localized online monitoring of physiological parameters. The microsystem fabrication on a wafer-level is based on a polyimide substrate and includes the patterning of platinum microelectrodes as well as epoxy and dry-film-resist insulation in a cost-effective thin-film and laminate process. A stable, electrodeposited silver/silver chloride reference electrode on-chip and a perm-selective membrane as an efficient interference rejection scheme are integrated on a wafer-level. Amperometric, electrochemical, enzyme-based biosensors for the neurotransmitter L-glutamate and the energy metabolite L-lactate have been developed. Hydrogel membranes or direct cross-linking as stable concepts for the enzyme immobilization are shown. Sensor performance including high selectivity, tailoring of sensitivity and long-term stability is discussed. For glutamate, a high sensitivity of 2.16 nAmm(-2) µM(-1) was found. For lactate, a variation in sensitivity between 2.6 and 32 nAmm(-2)mM(-1) was achieved by different membrane compositions. The in vivo application in an animal model is demonstrated by glutamate measurements in the brain of rats. Local glutamate alterations in the micromolar range and in nanoliter-range volumes can be detected and quantified with high reproducibility and temporal resolution. A novel, versatile platform for the integration of various electrochemical sensors on a small, flexible sensor strip for a variety of in vivo applications is presented. PMID:24880657

Weltin, Andreas; Kieninger, Jochen; Enderle, Barbara; Gellner, Anne-Kathrin; Fritsch, Brita; Urban, Gerald A

2014-11-15

69

Solvothermal Synthesis of ZnO Nanoparticles and Anti-Infection Application in Vivo.  

PubMed

Zinc oxide nanoparticles (ZnONPs) have been widely studied as the bacteriostatic reagents. However, synthesis of small ZnO nanoparticles with good monodispersion and stability in aqueous solution is still a challenge. Anti-infection research of ZnONPs used as antibacterial agent in vivo is rare. In this paper, a novel, sustainable, and simple method to synthesize ZnO nanoparticles with good monodispersion in aqueous low-temperature conditions and with a small molecule agent is reported. Inhibition zone test and the minimum inhibitory concentration test were performed to examine the antibacterial activity of ZnONPs against bacteria Staphylococcus aureus and Escherichia coli in vitro. For further application in vivo, low cytotoxicity and low acute toxicity in mice of ZnO were demonstrated. Finally, 4 nm ZnONPs combined with poly(vinyl alcohol) gel was used as antibacterial agent in rodent elytritis model, and significant anti-infection effect was proven. In one word, the present research would shed new light on the designing of antibacterial materials like ZnO with promising application in disinfection. PMID:25537255

Bai, Xiangyang; Li, Linlin; Liu, Huiyu; Tan, Longfei; Liu, Tianlong; Meng, Xianwei

2015-01-21

70

A modular wireless in vivo surgical robot with multiple surgical applications.  

PubMed

The use of miniature in vivo robots that fit entirely inside the peritoneal cavity represents a novel approach to laparoscopic surgery. Previous work demonstrates that both mobile and fixed-based robots can successfully operate inside the abdominal cavity. A modular wireless mobile platform has also been developed to provide surgical vision and task assistance. This paper presents an overview of recent test results of several possible surgical applications that can be accommodated by this modular platform. Applications such as a biopsy grasper, stapler and clamp, video camera, and physiological sensors have been integrated into the wireless platform and tested in vivo in a porcine model. The modular platform facilitates rapid development and conversion from one type of surgical task assistance to another. These self-contained surgical devices are much more transportable and much lower in cost than current robotic surgical assistants. These devices could ultimately be carried and deployed by non-medical personnel at the site of an injury. A remotely located surgeon could use these robots to provide critical first response medical intervention. PMID:19377127

Hawks, Jeff A; Rentschler, Mark E; Farritor, Shane; Oleynikov, Dmitry; Platt, Stephen R

2009-01-01

71

Highly purified mussel adhesive protein to secure biosafety for in vivo applications  

PubMed Central

Background Unique adhesive and biocompatibility properties of mussel adhesive proteins (MAPs) are known for their great potential in many tissue engineering and biomedical applications. Previously, it was successfully demonstrated that redesigned hybrid type MAP, fp-151, mass-produced in Gram-negative bacterium Escherichia coli, could be utilized as a promising adhesive biomaterial. However, purification of recombinant fp-151 has been unsatisfactory due to its adhesive nature and polarity which make separation of contaminants (especially, lipopolysaccharide, a toxic Gram-negative cell membrane component) very difficult. Results In the present work, we devised a high resolution purification approach to secure safety standards of recombinant fp-151 for the successful use in in vivo applications. Undesirable impurities were remarkably eliminated as going through sequential steps including treatment with multivalent ion and chelating agent for cell membrane washing, mechanical cell disruption, non-ionic surfactant treatment for isolated inclusion body washing, acid extraction of washed inclusion body, and ion exchange chromatography purification of acid extracted sample. Through various analyses, such as high performance liquid chromatographic purity assay, limulus amoebocyte lysate endotoxin assay, and in vitro mouse macrophage cell tests on inflammation, viability, cytotoxicity, and apoptosis, we confirmed the biological safety of bacterial-derived purified recombinant fp-151. Conclusions Through this purification design, recombinant fp-151 achieved 99.90% protein purity and 99.91% endotoxin reduction that nearly no inflammation response was observed in in vitro experiments. Thus, the highly purified recombinant MAP would be successfully used as a safety-secured in vivo bioadhesive for tissue engineering and biomedical applications. PMID:24725543

2014-01-01

72

A feasibility study of in vivo applications of single beam acoustic tweezers  

NASA Astrophysics Data System (ADS)

Tools that are capable of manipulating micro-sized objects have been widely used in such fields as physics, chemistry, biology, and medicine. Several devices, including optical tweezers, atomic force microscope, micro-pipette aspirator, and standing surface wave type acoustic tweezers have been studied to satisfy this need. However, none of them has been demonstrated to be suitable for in vivo and clinical studies. Single beam acoustic tweezers (SBAT) is a technology that uses highly focused acoustic beam to trap particles toward the beam focus. Its feasibility was first theoretically and experimentally demonstrated by Lee and Shung several years ago. Since then, much effort has been devoted to improving this technology. At present, the tool is capable of trapping a microparticle as small as 1 ?m, as well as a single red blood cell. Although in comparing to other microparticles manipulating technologies, SBAT has advantages of providing stronger trapping force and deeper penetration depth in tissues, and producing less tissue damage, its potential for in vivo applications has yet been explored. It is worth noting that ultrasound has been used as a diagnostic tool for over 50 years and no known major adverse effects have been observed at the diagnostic energy level. This paper reports the results of an initial attempt to assess the feasibility of single beam acoustic tweezers to trap microparticles in vivo inside of a blood vessel. The acoustic intensity of SBAT under the trapping conditions that were utilized was measured. The mechanical index and thermal index at the focus of acoustic beam were found to be 0.48 and 0.044, respectively, which meet the standard of commercial diagnostic ultrasound system.

Li, Ying; Lee, Changyang; Chen, Ruimin; Zhou, Qifa; Shung, K. Kirk

2014-10-01

73

Recent Advances in Intracellular and In Vivo ROS Sensing: Focus on Nanoparticle and Nanotube Applications  

PubMed Central

Reactive oxygen species (ROS) are increasingly being implicated in the regulation of cellular signaling cascades. Intracellular ROS fluxes are associated with cellular function ranging from proliferation to cell death. Moreover, the importance of subtle, spatio-temporal shifts in ROS during localized cellular signaling events is being realized. Understanding the biochemical nature of the ROS involved will enhance our knowledge of redox-signaling. An ideal intracellular sensor should therefore resolve real-time, localized ROS changes, be highly sensitive to physiologically relevant shifts in ROS and provide specificity towards a particular molecule. For in vivo applications issues such as bioavailability of the probe, tissue penetrance of the signal and signal-to-noise ratio also need to be considered. In the past researchers have heavily relied on the use of ROS-sensitive fluorescent probes and, more recently, genetically engineered ROS sensors. However, there is a great need to improve on current methods to address the above issues. Recently, the field of molecular sensing and imaging has begun to take advantage of the unique physico-chemical properties of nanoparticles and nanotubes. Here we discuss the recent advances in the use of these nanostructures as alternative platforms for ROS sensing, with particular emphasis on intracellular and in vivo ROS detection and quantification. PMID:23109815

Uusitalo, Larissa M.; Hempel, Nadine

2012-01-01

74

The synthesis, characterisation and in vivo study of a bioceramic for potential tissue regeneration applications  

PubMed Central

Hydroxyapatite (HAP) is a biocompatible ceramic that is currently used in a number of current biomedical applications. Recently, nanometre scale forms of HAP have attracted considerable interest due to their close similarity to the inorganic mineral component of the bone matrix found in humans. In this study ultrafine nanometre scale HAP powders were prepared via a wet precipitation method under the influence of ultrasonic irradiation. The resulting powders were compacted and sintered to form a series of ceramic pellets with a sponge-like structure with varying density and porosity. The crystalline structure, size and morphology of the powders and the porous ceramic pellets were investigated using advanced characterization techniques. The pellets demonstrated good biocompatibility, including mixed cell colonisation and matrix deposition, in vivo following surgical implantation into sheep M. latissimus dorsi. PMID:25168046

Poinern, Gérrard Eddy Jai; Brundavanam, Ravi Krishna; Thi Le, Xuan; Nicholls, Philip K.; Cake, Martin A.; Fawcett, Derek

2014-01-01

75

Automatic temperature control for MR-guided interstitial ultrasound ablation in liver using a percutaneous applicator: ex vivo and in vivo initial studies.  

PubMed

Image-guided thermal ablation offers minimally invasive options for treating hepatocellular carcinoma and colorectal metastases in liver. Here, the feasibility and the potential benefit of active temperature control for MR-guided percutaneous ultrasound ablation was investigated in pig liver. An MR-compatible interstitial ultrasound applicator (flat transducer), a positioning system with rotation-translation guiding frame, and an orbital ring holder were developed. Step-by-step rotated elementary lesions were produced, each being formed by directive heating of a flame-shaped volume of tissue. In vivo feasibility of automatic temperature control was investigated on two pigs. Proton Resonance Frequency Shift (PRFS)-based MR thermometry was performed on a 1.5-T clinical scanner, using SENSE acceleration and respiratory gating. MR follow-up of animals and macroscopic analysis were performed at 3 and, respectively, 4 days postprocedure. No sonication-related radiofrequency artifacts were detected on MR images. The temperature controller converged to the target elevation within +/-2 degrees C unless the requested power level exceeded the authorized limit. Large variability of the controller's applied powers from one sonication to another was found both ex vivo and in vivo, indicating highly anisotropic acoustic coupling and/or tissue response to identical beam pattern along different radial directions. The automatic control of the temperature enabled reproducible shape of lesions (15 +/- 2 mm radial depth). PMID:20187177

Delabrousse, Eric; Salomir, Rares; Birer, Alain; Paquet, Christian; Mithieux, François; Chapelon, Jean-Yves; Cotton, François; Lafon, Cyril

2010-03-01

76

In vivo application of a small molecular weight antifungal protein of Penicillium chrysogenum (PAF)  

SciTech Connect

The antifungal protein of Penicillium chrysogenum (PAF) inhibits the growth of important pathogenic filamentous fungi, including members of the Aspergillus family and some dermatophytes. Furthermore, PAF was proven to have no toxic effects on mammalian cells in vitro. To prove that PAF could be safely used in therapy, experiments were carried out to investigate its in vivo effects. Adult mice were inoculated with PAF intranasally in different concentrations, up to 2700 ?g·kg{sup ?1} daily, for 2 weeks. Even at the highest concentration – a concentration highly toxic in vitro for all affected molds – used, animals neither died due to the treatment nor were any side effects observed. Histological examinations did not find pathological reactions in the liver, in the kidney, and in the lungs. Mass spectrometry confirmed that a measurable amount of PAF was accumulated in the lungs after the treatment. Lung tissue extracts from PAF treated mice exerted significant antifungal activity. Small-animal positron emission tomography revealed that neither the application of physiological saline nor that of PAF induced any inflammation while the positive control lipopolysaccharide did. The effect of the drug on the skin was examined in an irritative dermatitis model where the change in the thickness of the ears following PAF application was found to be the same as in control and significantly less than when treated with phorbol-12-myristate-13-acetate used as positive control. Since no toxic effects of PAF were found in intranasal application, our result is the first step for introducing PAF as potential antifungal drug in therapy. - Highlights: • PAF, the antifungal protein of Penicillium chrysogenum, was not toxic in mice. • Its intranasal application didn't induce pathological reactions in the lung. • PAF retained its antifungal activity in lung extracts. • Its application on the skin did not cause inflammation.

Palicz, Zoltán; Jenes, Ágnes; Gáll, Tamás [Department of Physiology, Medical and Health Science Center, University of Debrecen, Debrecen (Hungary); Miszti-Blasius, Kornél [Department of Clinical Biochemistry and Molecular Pathology, Medical and Health Science Center, University of Debrecen, Debrecen (Hungary); Kollár, Sándor; Kovács, Ilona [Department of Pathology, Kenézy Hospital LTD, Debrecen (Hungary); Emri, Miklós; Márián, Teréz [Department of Nuclear Medicine, Medical and Health Science Center, University of Debrecen, Debrecen (Hungary); Leiter, Éva; Pócsi, István [Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, Centre of Arts, Humanities and Sciences, University of Debrecen, Debrecen (Hungary); Cs?sz, Éva; Kalló, Gerg? [Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Medical and Health Science Center, University of Debrecen, Debrecen (Hungary); Heged?s, Csaba; Virág, László [Department of Medical Chemistry, Medical and Health Science Center, University of Debrecen, Debrecen (Hungary); Csernoch, László [Department of Physiology, Medical and Health Science Center, University of Debrecen, Debrecen (Hungary); Szentesi, Péter, E-mail: szentesi.peter@med.unideb.hu [Department of Physiology, Medical and Health Science Center, University of Debrecen, Debrecen (Hungary)

2013-05-15

77

Application of NIR fluorescent markers to quantify expression level of HER2 receptors in carcinomas in vivo  

NASA Astrophysics Data System (ADS)

HER2 overexpression has been associated with a poor prognosis and resistance to therapy in breast cancer patients. However, quantitative estimates of this important characteristic have been limited to ex vivo ELISA essays of tissue biopsies and/or PET. We develop a novel approach in optical imaging, involving specific probes, not interfering with the binding of the therapeutic agents, thus, excluding competition between therapy and imaging. Affibody-based molecular probes seem to be ideal for in vivo analysis of HER2 receptors using near-infrared optical imaging. Fluorescence intensity distributions, originating from specific markers in the tumor area, can reveal the corresponding fluorophore concentration. We use temporal changes of the signal from a contrast agent, conjugated with HER2-specific Affibody as a signature to monitor in vivo the receptors status in mice with different HER2 over-expressed tumor models. Kinetic model, incorporating saturation of the bound ligands in the tumor area due to HER2 receptor concentration, is suggested to analyze relationship between tumor cell characteristics, i.e., HER2 overexpression, obtained by traditional ("golden standard") ex vivo methods (ELISA), and parameters, estimated from the series of images in vivo. Observed correlation between these parameters and HER2 overexpression substantiates application of our approach to quantify HER2 concentration in vivo.

Chernomordik, Victor; Hassan, Moinuddin; Lee, Sang Bong; Zielinski, Rafal; Capala, Jacek; Gandjbakhche, Amir

2010-02-01

78

Application of FRET Technology to the In Vivo Evaluation of Therapeutic Nucleic Acids (ANTs)  

NASA Astrophysics Data System (ADS)

Developing applications for therapeutic nucleic acids (TNAs) (i.e. ribozymes, antisense oligodeoxynucleotides (AS-ODNs), siRNA and aptamers) requires a reporter system designed to rapidly evaluate their in vivo effect. To this end we designed a reporter system based on the fluorescence resonance energy transfer (FRET) engineered to release the FRET effect produced by two green fluorescent protein (GFP) variants linked by a TNA target site. Because the FRET effect occurs instantaneously when two fluorophores are very close to each other (>100nm) stimulating emission of the acceptor fluorophore by the excitation of the donor fluorophore it has been widely use to reveal interactions between molecules. The present system (FRET2) correlates the FRET effect with the in vivo activity of distinct types of TNAs based on a model consisting of RNA from human papillomavirus type 16 (HPV-16) previously shown accessible to TNAs. HPV-16 is the most common papillomavirus associated with cervical cancer, the leading cause of death by cancer in México. The FRET2 system was first tested in vitro and then used in bacteria in which transcription is linked to translation allowing controlled expression and rapid evaluation of the FRET2 protein. To assure accessibility of the target mRNA to TNAs, the FRET2 mRNA was probed by RNaseH assays prior FRET testing. The fluorescence features of the FRET2 system was tested with different FRET-producing GFP donor-acceptor pairs leading to selection of green (donor) and yellow (acceptor) variants of GFP as the most efficient. Modifications in aminoacid composition and linker length of the target sequence did not affect FRET efficiency. In vivo AS-ODN-mediated destruction of the chimerical FRET2 reporter mRNA resulted in the recovery of GFP fluorescent spectrum in a concentration and time dependent manner. Reported anti-HPV ribozymes were also tested with similar results. Therefore, we conclude that the FRET effect can be a useful tool in the development of TNAs.

Benítez-Hess, María Luisa; Alvarez-Salas, Luis Marat

2007-02-01

79

Application of the laser capture microdissection technique for molecular definition of skeletal cell differentiation in vivo.  

PubMed

Laser capture microdissection (LCM) method allows selection of individual or clustered cells from intact tissues. This technology enables one to pick cells from tissues that are difficult to study individually, sort the anatomical complexity of these tissues, and make the cells available for molecular analyses. Following the cells' extraction, the nucleic acids and proteins can be isolated and used for multiple applications that provide an opportunity to uncover the molecular control of cellular fate in the natural microenvironment. Utilization of LCM for the molecular analysis of cells from skeletal tissues will enable one to study differential patterns of gene expression in the native intact skeletal tissue with reliable interpretation of function for known genes as well as to discover novel genes. Variability between samples may be caused either by differences in the tissue samples (different areas isolated from the same section) or some variances in sample handling. LCM is a multi-task technology that combines histology, microscopy work, and dedicated molecular biology. The LCM application will provide results that will pave the way toward high throughput profiling of tissue-specific gene expression using Gene Chip arrays. Detailed description of in vivo molecular pathways will make it possible to elaborate on control systems to apply for the repair of genetic or metabolic diseases of skeletal tissues. PMID:18463821

Benayahu, Dafna; Socher, Rina; Shur, Irena

2008-01-01

80

Fluorescence spectroscopy of gastrointestinal tumors: in vitro studies and in vivo clinical applications  

NASA Astrophysics Data System (ADS)

The limitations of standard endoscopy for detection and evaluation of cancerous changes in the gastrointestinal tract (GIT) are significant challenges and initiate development of new diagnostic modalities. Therefore many spectral and optical techniques are applied recently into the clinical practice for obtaining qualitatively and quantitatively new data from gastrointestinal neoplasia with different levels of clinical applicability and diagnostic success. Fluorescence imaging has been one of the most promising technologies in this area. The technique is very topical with its practical application in intra-operative, image-guided resection of tumors, because it permits minimal surgery intervention and friendly therapeutic conditions. The investigations presented here are based on in vitro measurements of excitation-emission matrices (EEM) for GIT neoplasia and in vivo measurements in the frames of initial clinical trial for tumor fluorescence spectra detection, applied for introduction of spectroscopic diagnostic system for optical biopsy of GIT tumors in the daily clinical practice of the University Hospital "Queen Jiovanna - ISUL"- Sofia. Autofluorescence and exogenous fluorescence signals are detected from normal mucosa, inflammation, dysphasia and carcinoma and main spectral features are evaluated. The systems and methods developed for diagnosis and monitoring could open new dimensions in diagnostic and real-time tumor resection. This will make the entire procedure more personal, patient friendly and effective and will help for further understanding of the tumor nature.

Angelova, L.; Borisova, E.; Zhelyazkova, Al.; Keremedchiev, M.; Vladimirov, B.; Avramov, L.

2013-11-01

81

Laccase?catalysed oxidations of naturally occurring phenols: from in vivo biosynthetic pathways to green synthetic applications  

PubMed Central

Summary Laccases are oxidases that contain several copper atoms, and catalyse single?electron oxidations of phenolic compounds with concomitant reduction of oxygen to water. The enzymes are particularly widespread in ligninolytic basidiomycetes, but also occur in certain prokaryotes, insects and plants. Depending on the species, laccases are involved in various biosynthetic processes contributing to carbon recycling in land ecosystems and the morphogenesis of biomatrices, wherein low?molecular?weight naturally occurring phenols serve as key enzyme substrates. Studies of these in vivo synthetic pathways have afforded new insights into fungal laccase applicability in green synthetic chemistry. Thus, we here review fungal laccase?catalysed oxidations of naturally occurring phenols that are particularly relevant to the synthesis of fine organic chemicals, and we discuss how the discovered synthetic strategies mimic laccase?involved in vivo pathways, thus enhancing the green nature of such reactions. Laccase?catalysed in vivo processes yield several types of biopolymers, including those of cuticles, lignin, polyflavonoids, humus and the melanin pigments, using natural mono? or poly?phenols as building blocks. The in vivo synthetic pathways involve either phenoxyl radical?mediated coupling or cross?linking reactions, and can be adapted to the design of in vitro oxidative processes involving fungal laccases in organic synthesis; the laccase substrates and the synthetic mechanisms reflect in vivo processes. Notably, such in vitro synthetic pathways can also reproduce physicochemical properties (e.g. those of chromophores, and radical?scavenging, hydration and antimicrobial activities) found in natural biomaterials. Careful study of laccase?associated in vivo metabolic pathways has been rewarded by the discovery of novel green applications for fungal laccases. This review comprehensively summarizes the available data on laccase?catalysed biosynthetic pathways and associated applications in fine chemical syntheses. PMID:21791030

Jeon, Jong?Rok; Baldrian, Petr; Murugesan, Kumarasamy; Chang, Yoon?Seok

2012-01-01

82

Synthesis and surface modification of magnetic nanoparticles for in vivo biomedical applications  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles (MNPs) possess unique magnetic properties and the ability to function at the cellular and molecular level of biological interactions making them an attractive platform to serve as contrast agents for magnetic resonance imaging (MRI) and as carriers for drug delivery. Recent advances in nanotechnology have improved the ability to engineer the features and properties of MNPs allowing them to be tailored specifically for these biomedical applications. MNPs composed of metallic, oxide, and nanoalloy cores and a variety of protective coatings are being investigated for applications in the detection, diagnosis, and treatment of malignant tumors, cardiovascular disease, and neurological disease. To better address specific clinical needs, MNPs with higher magnetic moments, non-fouling surfaces, and increased functionalities are now being developed. The goal of this interdisciplinary research is to develop novel superparamagnetic nanoprobes for non-invasive cancer diagnosis and treatment. This strategy utilizes iron oxide nanoparticles coated with various biocompatible polymers, such as poly(ethylene glycol) (PEG) and chitosan, to serve as both a contrast agent for MRI and a carrier for drug delivery. In this project, we have conjugated various targeting agents, such as folic acid (FA) and chlorotoxin (CTX), to these iron oxide nanoparticles to improve their tumor specific accumulation. The folate receptor is known to be overexpressed on the surfaces of many human tumor cells, including ovarian, lung, breast, endometrial, renal, and colon cancers, while CTX binds with high affinity to gliomas, medulloblastomas, and other tumors of the neuroectodermal origin. To evaluate its effectiveness as a targeted drug carrier, methotrexate (MTX), a convention chemotherapeutic agent, was conjugated to iron oxide nanoparticles in combination with CTX. Specific tumor cell targeting of our nanoparticle system has been demonstrated through increased contrast enhancement both in vitro and in vivo in MRI experiments. The successful application of such smart molecular imaging probes will have a significant clinical impact on improved diagnosis and treatment of malignant tumors.

Sun, Conroy Ghin Chee

83

The Application of in vivo laser scanning confocal microscopy as a tool of conjunctival in vivo cytology in the diagnosis of dry eye ocular surface disease  

PubMed Central

Purpose To evaluate the applicability of in vivo laser scanning confocal microscopy as a tool of conjunctival cytology in a prospective case-control study. Methods Nineteen right eyes of 19 Sjogren’s syndrome dry eye patients (19 females; mean age: 55.8±15 years), and 18 right eyes of 18 normal healthy control subjects (12 females and 6 males; mean age: 50.8±14 years) were evaluated in this study. The eyes were analyzed by the Heidelberg retina tomography (HRTII)/Rostock cornea module (RCM). Ocular surface and tear function tests including vital stainings (fluorescein and Rose Bengal), Schirmer test, tear film break up time (BUT), and conjunctival impression cytology were performed. After obtaining the confocal microscopy images, the mean individual epithelial cell area (MIECA), and nucleocytoplasmic (N/C) ratio were analyzed. The correlation between confocal microscopy and impression cytology parameters was also investigated. Results The BUT, Schirmer test values, vital staining scores and squamous metaplasia grades in impression cytology were significantly worse in dry eye patients compared to controls (p<0.0001). The MIECA and the mean N/C ratios were worse in dry eye subjects compared to controls both in impression cytology and in vivo confocal microscopy (p<0.0001) with no significant differences between these parameters when the two examination techniques were compared. The MIECA and N/C ratio in conjunctival impression cytology showed significant correlation with the corresponding confocal microscopy parameters (MIECA, r2:0.557 ; N/C, r2:0.765). Conclusions Laser scanning confocal microscopy seems to be an efficient non-invasive tool in the evaluation of phenotypic alterations of the conjunctival epithelium in dry eye disease. N/C ratio and MIECA appear to be two promising and new parameters of in vivo confocal cytology in the assessment of the ocular surface in dry eye disease. PMID:21139693

Kojima, Takashi; Matsumoto, Yukihiro; Tsubota, Kazuo

2010-01-01

84

Multiphoton fluorescence recovery after photobleaching: Advancements for novel in vivo applications  

NASA Astrophysics Data System (ADS)

Multiphoton fluorescence recovery after photobleaching (MP-FRAP) is a laser microscopy technique used to probe the transport properties of macromolecules in biological systems. MP-FRAP utilizes two-photon fluorescence and photobleaching to produce a three-dimensionally resolved diffusion coefficient for an ensemble of molecules in the region of the two-photon focal volume. This thesis describes two fundamental improvements to the MP-FRAP technique, which are vital steps to enable MP-FRAP to be applied to the complex in vivo environment. In Chapter 1, we lay the groundwork for our discussion of these advancements by introducing the MP-FRAP technique and the physics upon which it is based. We begin with a description of fluorescence and diffusion and discuss their importance in biomedical research. Next, we describe how two-photon fluorescence and photobleaching are applied to a diffusing system to measure the diffusion coefficient via fluorescence recovery after photobleaching (FRAP). Then, we take the reader through the evolution of FRAP, which leads to the application of two- photon fluorescence and photobleaching to produce MP-FRAP. Along the way, we highlight applications and advancements of the FRAP techniques, and introduce fluorescence correlation spectroscopy, a popular complement to FRAP. In Chapter 2, we collect the experimental methods for the studies presented in Chapters 3 and 4. We begin with an in-depth discussion of our work to build and troubleshoot our MP-FRAP apparatus, followed by a detailed description of our data analysis protocol. Next, we delve into the specific methods for producing computer generated data and fits, as well as in vitro and in vivo experimental data, for our work in Chap. 3 on improving MP-FRAP to measure diffusion in the presence of convective flow. We end with a description of the Monte Carlo algorithm we developed for our work in Chap. 4 to model diffusion and multiphoton fluorescence recovery after photobleaching in the presence of reflective boundaries of various geometries. In Chapter 3, we develop an improved analytical model of multiphoton fluorescence recovery after photobleaching that includes the effects of convective flows within a system. We use computer generated data and fits to explore the effect of convective flow on the shape and speed of fluorescence recovery, and to estimate the range of diffusion coefficients and flow speeds over which this new "diffusion-convection" model yields accurate diffusion coefficients (as compared to the diffusion-only model). We then demonstrate the validity of the diffusion-convection model through in vitro experimentation in systems with known diffusion coefficients and known flow speeds, and show that the diffusion-convection model enables accurate determination of the diffusion coefficient via MP-FRAP, even when significant flows are present. We conclude by demonstrating the effectiveness of the diffusion-convection model in vivo by measuring the diffusion coefficient and flow speed within tumor vessels of 4T1 murine mammary adenocarcinomas implanted in the dorsal skinfold chamber. In Chapter 4, we present our work that allows MP-FRAP to be performed accurately near reflective boundaries of various geometries. Using Monte Carlo techniques, we first generate an initial distribution of bleached molecules, then simulate their diffusion away from the initial distribution, thereby producing fluorescence vs. time recovery curves in the region of the initial bleached distribution. These curves are then fit to the standard analytical MP-FRAP model to produce a diffusion coefficient. By introducing solid barriers into the model in the region of the initial bleached distribution, we learn how the presence of harriers of different geometries affects the measurement of diffusion via MP-FRAP. Finally, we supply ranges of barrier positions for each geometry within which MP-FR AP can confidently be employed to measure accurate diffusion coefficients.

Sullivan, Kelley Diane

85

Three-photon luminescence of gold nanorods and its applications for high contrast tissue and deep in vivo brain imaging.  

PubMed

Gold nanoparticles can be used as contrast agents for bio-imaging applications. Here we studied multi-photon luminescence (MPL) of gold nanorods (GNRs), under the excitation of femtosecond (fs) lasers. GNRs functionalized with polyethylene glycol (PEG) molecules have high chemical and optical stability, and can be used as multi-photon luminescent nanoprobes for deep in vivo imaging of live animals. We have found that the depth of in vivo imaging is dependent upon the transmission and focal capability of the excitation light interacting with the GNRs. Our study focused on the comparison of MPL from GNRs with two different aspect ratios, as well as their ex vivo and in vivo imaging effects under 760 nm and 1000 nm excitation, respectively. Both of these wavelengths were located at an optically transparent window of biological tissue (700-1000 nm). PEGylated GNRs, which were intravenously injected into mice via the tail vein and accumulated in major organs and tumor tissue, showed high image contrast due to distinct three-photon luminescence (3PL) signals upon irradiation of a 1000 nm fs laser. Concerning in vivo mouse brain imaging, the 3PL imaging depth of GNRs under 1000 nm fs excitation could reach 600 ?m, which was approximately 170 ?m deeper than the two-photon luminescence (2PL) imaging depth of GNRs with a fs excitation of 760 nm. PMID:25553113

Wang, Shaowei; Xi, Wang; Cai, Fuhong; Zhao, Xinyuan; Xu, Zhengping; Qian, Jun; He, Sailing

2015-01-01

86

Three-Photon Luminescence of Gold Nanorods and Its Applications for High Contrast Tissue and Deep In Vivo Brain Imaging  

PubMed Central

Gold nanoparticles can be used as contrast agents for bio-imaging applications. Here we studied multi-photon luminescence (MPL) of gold nanorods (GNRs), under the excitation of femtosecond (fs) lasers. GNRs functionalized with polyethylene glycol (PEG) molecules have high chemical and optical stability, and can be used as multi-photon luminescent nanoprobes for deep in vivo imaging of live animals. We have found that the depth of in vivo imaging is dependent upon the transmission and focal capability of the excitation light interacting with the GNRs. Our study focused on the comparison of MPL from GNRs with two different aspect ratios, as well as their ex vivo and in vivo imaging effects under 760 nm and 1000 nm excitation, respectively. Both of these wavelengths were located at an optically transparent window of biological tissue (700-1000 nm). PEGylated GNRs, which were intravenously injected into mice via the tail vein and accumulated in major organs and tumor tissue, showed high image contrast due to distinct three-photon luminescence (3PL) signals upon irradiation of a 1000 nm fs laser. Concerning in vivo mouse brain imaging, the 3PL imaging depth of GNRs under 1000 nm fs excitation could reach 600 ?m, which was approximately 170 ?m deeper than the two-photon luminescence (2PL) imaging depth of GNRs with a fs excitation of 760 nm. PMID:25553113

Wang, Shaowei; Xi, Wang; Cai, Fuhong; Zhao, Xinyuan; Xu, Zhengping; Qian, Jun; He, Sailing

2015-01-01

87

Studies on dental erosion: An in vivo-in vitro model of endogenous dental erosion-its application to testing protection b flouride gel application  

Microsoft Academic Search

Background: The objective in this study was to develop an in vivo-in vitro model of endogenous erosion, with a view to exploring the potential for some degree of its control by the use of topical fluoride gel application to teeth. Methods: Six volunteers each wore a small clasp retained palatal acrylic appliance to which six sterilized enamel tiles were bonded.

L. Jones; D. Lekkas; D. Hunt; J. McIntyre; W. Rafir

2002-01-01

88

A Freehand Ultrasound Elastography System with Tracking for In-vivo Applications  

PubMed Central

Ultrasound transducers are commonly tracked in modern ultrasound navigation/guidance systems. In this paper, we demonstrate the advantages of incorporating tracking information into ultrasound elastography for clinical applications. First, we address a common limitation of freehand palpation: speckle decorrelation due to out-of-plane probe motion. We show that by automatically selecting pairs of radio frequency (RF) frames with minimal lateral and out-of-plane motions combined with a fast and robust displacement estimation technique greatly improves in-vivo elastography results. We also use tracking information and image quality measure to fuse multiple images with similar strain that are taken roughly from the same location to obtain a high quality elastography image. Finally, we show that tracking information can be used to give the user partial control over the rate of compression. Our methods are tested on tissue mimicking phantom and experiments have been conducted on intra-operative data acquired during animal and human experiments involving liver ablation. Our results suggest that in challenging clinical conditions, our proposed method produces reliable strain images and eliminates the need for a manual search through the ultrasound data in order to find RF pairs suitable for elastography. PMID:23257351

Foroughi, Pezhman; Kang, Hyun-Jae; Carnegie, Daniel A.; van Vledder, Mark G.; Choti, Michael A.; Hager, Gregory D.; Boctor, Emad M.

2012-01-01

89

AirSR, a [2Fe-2S] Cluster-Containing Two-Component System, Mediates Global Oxygen Sensing and Redox Signaling in Staphylococcus aureus  

PubMed Central

Oxygen sensing and redox signaling significantly affect bacterial physiology and host-pathogen interaction. Here we show that a Staphylococcus aureus two-component system, AirSR (anaerobic iron-sulfur cluster-containing redox sensor regulator, formerly YhcSR), responds to oxidation signals (O2, H2O2, NO, etc) by using a redox-active [2Fe-2S] cluster in the sensor kinase AirS. Mutagenesis studies demonstrate that the [2Fe-2S] cluster is essential for the kinase activity of AirS. We have also discovered that a homolog of IscS (SA1450) in S. aureus is active as a cysteine desulfurase, which enables the in vitro reconstitution of the [2Fe-2S] cluster in AirS. Phosphorylation assays show that the oxidized AirS with a [2Fe-2S]2+ cluster is the fully active form of the kinase but not the apo-AirS nor the reduced AirS possessing a [2Fe-2S]+ cluster. Over-oxidation by prolonged exposure to O2 or contact with H2O2 or NO led to inactivation of AirS. Transcriptome analysis revealed that mutation of airR impacts the expression of ~355 genes under anaerobic conditions. Moreover, the mutant strain displayed increased resistance toward H2O2, vancomycin, norfloxacin, and ciprofloxacin under anaerobic conditions. Together, our results show that S. aureus AirSR is a redox-dependent global regulatory system that plays important roles in gene regulation using a redox active Fe-S cluster under O2-limited conditions. PMID:22122613

Sun, Fei; Ji, Quanjiang; Jones, Marcus B.; Deng, Xin; Liang, Haihua; Frank, Bryan; Telser, Joshua; Peterson, Scott N.; Bae, Taeok; He, Chuan

2011-01-01

90

Development of HiLo Microscope and its use in In-Vivo Applications  

NASA Astrophysics Data System (ADS)

The functionality of achieving optical sectioning in biomedical research is invaluable as it allows for visualization of a biological sample at different depths while being free of background scattering. Most current microscopy techniques that offer optical sectioning, unfortunately, require complex instrumentation and thus are generally costly. HiLo microscopy, on the other hand, offers the same functionality and advantage at a relatively low cost. Hence, the work described in this thesis involves the design, build, and application of a HiLo microscope. More specifically, a standalone HiLo microscope was built in addition to implementing HiLo microscopy on a standard fluorescence microscope. In HiLo microscopy, optical sectioning is achieved by acquiring two different types of images per focal plane. One image is acquired under uniform illumination and the other is acquired under speckle illumination. These images are processed using an algorithm that extracts in-focus information and removes features and glare that occur as a result of background fluorescence. To show the benefits of the HiLo microscopy, several imaging experiments on various samples were performed under a HiLo microscope and compared against a traditional fluorescence microscope and a confocal microscope, which is considered the gold standard in optical imaging. In-vitro and ex-vivo imaging was performed on a set of pollen grains, and optically cleared mouse brain and heart slices. Each of these experiments showed great reduction in background scattering at different depths under HiLo microscopy. More importantly, HiLo imaging of optically cleared heart slice demonstrated emergence of different vasculature at different depths. Reduction of out-of-focus light increased the spatial resolution and allowed better visualization of capillary vessels. Furthermore, HiLo imaging was tested in an in-vivo model of a rodent dorsal window chamber model. When imaging the same sample under confocal microscope, the results were comparable between the two modalities. Additionally, a method of achieving blood flow maps at different depth using a combination of HiLo and LSI imaging is also discussed. The significance of this combined technique could help categorize blood flow to particular depths; this can help improve outcomes of medical treatments such pulse dye laser and photodynamic therapy treatments.

Patel, Shreyas J.

91

Sustained Growth of the Ex Vivo Ablation Zones' Critical Short Axis Using Gas-cooled Radiofrequency Applicators  

SciTech Connect

Purpose: To evaluate the ablation zones created with a gas-cooled bipolar radiofrequency applicator performed on ex vivo bovine liver tissue. Materials and Methods: A total of 320 ablations with an internally gas-cooled bipolar radiofrequency applicator were performed on fresh ex vivo bovine liver tissue, varying the ablation time (5, 10, 15, and 20 min), power (20, 30, 40, and 50 W), and gas pressure of the CO{sub 2} used for cooling (585, 600, 615, 630, 645 psi), leading to a total of 80 different parameter combinations. Size and shape of the white coagulation zone were assessed. Results: The largest complete ablation zone was achieved after 20 min of implementing 50 W and 645 psi, resulting in a short axis of mean 46 {+-} 1 mm and a long axis of 56 {+-} 2 mm (mean {+-} standard deviation). Short-axis diameters increased between 5 and 20 min of ablation time at 585 psi (increase of the short axis was 45% at 30 W, 29% at 40 W, and 39% at 50 W). This increase was larger at 645 psi (113% at 30 W, 67% at 40 W, and 70% at 50 W). Macroscopic assessment and NADH (nicotinamide adenine dinucleotide) staining revealed incompletely ablated tissue along the needle track in 18 parameter combinations including low-power settings (20 and 30 W) and different cooling levels and ablation times. Conclusion: Gas-cooled radiofrequency applicators increase the short-axis diameter of coagulation in an ex vivo setting if appropriate parameters are selected.

Rempp, Hansjoerg, E-mail: hansjoerg.rempp@med.uni-tuebingen.de [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Scharpf, Marcus [Insitute of Pathology, Eberhard Karls University of Tuebingen, Department of General Pathology and Pathological Anatomy (Germany); Voigtlaender, Matthias [ERBE Elektromedizin GmbH (Germany); Schraml, Christina; Schmidt, Diethard [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Fend, Falko [Insitute of Pathology, Eberhard Karls University of Tuebingen, Department of General Pathology and Pathological Anatomy (Germany); Claussen, Claus D. [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Enderle, Markus D. [ERBE Elektromedizin GmbH (Germany); Pereira, Philippe L. [Klinik fuer Radiologie, Minimalinvasive Therapien und Nuklearmedizin (Germany); Clasen, Stephan [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany)

2011-02-15

92

Biosensors based on inorganic nanoparticles with biomimetic properties: Biomedical applications and in vivo cytotoxicity measurements  

NASA Astrophysics Data System (ADS)

The rapid progress of nanotechnology and advanced nanomaterials production offer significant opportunities for designing powerful biosensing devices with enhanced performances. This thesis introduces ceria (CeO 2) nanoparticles and its congeners as a new class of materials with huge potential in bioanalytical and biosensing applications. Unique redox, catalytic and oxygen storage/release properties of ceria nanoparticles, originating from their dual oxidation state are used to design biomedical sensors with high sensitivity and low oxygen dependency. This thesis describes a new approach for fabrication of implantable microbiosensors designed for monitoring neurological activity in physiological conditions. Understanding the mechanisms involved in neurological signaling and functioning is of great physiological importance. In this respect, the development of effective methods that allow accurate detection and quantification of biological analytes (i.e. L-glutamate and glucose) associated with neurological processes is of paramount importance. The performance of most analytical techniques currently used to monitor L-glutamate and glucose is suboptimal and only a limited number of approaches address the problem of operation in oxygen-restricted conditions, such as ischemic brain injury. Over the past couple of years, enzyme based biosensors have been used to investigate processes related to L-glutamate release/uptake and the glucose cycle within the brain. However, most of these sensors, based on oxidoreductase enzymes, do not work in conditions of limited oxygen availability. This thesis presents the development of a novel sensing technology for the detection of L-glutamate and glucose in conditions of oxygen deprivation. This technology provides real-time assessment of the concentrations of these analytes with high sensitivity, wide linear range, and low oxygen dependence. The fabrication, characterization and optimization of enzyme microbiosensors are discussed. This work introduces a new generic approach of improving the sensitivity of oxidase-based enzymatic assays and indicates that ceria and its mixture with other metal oxide nanoparticles could be used to minimize the problems associated with variations of the oxygen. These materials have great potential in bioanalytical and biotechnological applications and offer great opportunities for development of implantable sensing devices for in vivo and in vitro monitoring of analytes of clinical relevance. Additionally, this thesis evaluates the toxicity of different metal and metal oxide nanoparticles by using zebrafish embryos as a toxicological target. Because of their similarities with other vertebrates, rapid development and low cost, zebrafish embryos are ideal animal models for probing toxicological effects of engineered nanomaterials. Among the nanomaterials tested, nickel nanoparticles were characterized by high toxicity and induced delayed development and morphological malformations, while metal oxides nanoparticles (i.e. ceria nanoparticles) had no toxic effects.

Ispas, Cristina R.

93

Informatics approach using metabolic reactivity classifiers to link in vitro to in vivo data in application to the ToxCast Phase I dataset  

EPA Science Inventory

Strategic combinations and tiered application of alternative testing methods to replace or minimize the use of animal models is attracting much attention. With the advancement of high throughput screening (HTS) assays and legacy databases providing in vivo testing results, suffic...

94

A sparse-projection computed tomography reconstruction method for in vivo application of in-line phase-contrast imaging  

PubMed Central

Background In recent years, X-ray phase-contrast imaging techniques have been extensively studied to visualize weakly absorbing objects. One of the most popular methods for phase-contrast imaging is in-line phase-contrast imaging (ILPCI). Combined with computed tomography (CT), phase-contrast CT can produce 3D volumetric images of samples. To date, the most common reconstruction method for phase-contrast X-ray CT imaging has been filtered back projection (FBP). However, because of the impact of respiration, lung slices cannot be reconstructed in vivo for a mouse using this method. Methods for reducing the radiation dose and the sampling time must also be considered. Methods This paper proposes a novel method of in vivo mouse lung in-line phase-contrast imaging that has two primary improvements compared with recent methods: 1) using a compressed sensing (CS) theory-based CT reconstruction method for the in vivo in-line phase-contrast imaging application and 2) using the breathing phase extraction method to address the lung and rib cage movement caused by a live mouse’s breathing. Results Experiments were performed to test the breathing phase extraction method as applied to the lung and rib cage movement of a live mouse. Results with a live mouse specimen demonstrate that our method can reconstruct images of in vivo mouse lung. Conclusions The results demonstrate that our method could deal with vivo mouse’s breathing and movements, meanwhile, using less sampling data than FBP while maintaining the same high quality. PMID:23898866

2013-01-01

95

Preparation of 2 nm gold nanoparticles for in vitro and in vivo applications  

PubMed Central

Summary Gold nanoparticles have been a versatile tool in recent years for the exploration of biological systems. However, challenges with purification and adequate surface coverage limit the biocompatibility of gold nanoparticles. Here, we describe a detailed procedure for the synthesis, purification, and functionalization of biologically compatible gold nanoparticles for in vitro and in vivo studies. PMID:23918325

Moyano, Daniel F.; Duncan, Bradley; Rotello, Vincent M.

2014-01-01

96

The application of dermal papillary rings in dermatology by in vivo confocal laser scanning microscopy  

Microsoft Academic Search

Confocal laser scanning microscopy (CLSM) allows noninvasive visualization of human skin in vivo, without needing to fix or section the tissue. Melanocytes and pigmented keratinocytes at the level of the basal layer form bright dermal papillary rings which are readily amenable to identify in confocal images. Our purpose was to explore the role of dermal papillary rings in assessment of

W. Z. Xiang; A. E. Xu; J. Xu; Z. G. Bi; Y. B. Shang; Q. S. Ren

2010-01-01

97

Development of in vivo constitutive models for liver: application to surgical simulation.  

PubMed

Advancements in real-time surgical simulation techniques have provided the ability to utilize more complex nonlinear constitutive models for biological tissues which result in increased haptic and graphic accuracy. When developing such a model, verification is necessary to determine the accuracy of the force response as well as the magnitude of tissue deformation for tool-tissue interactions. In this study, we present an experimental device which provides the ability to obtain force-displacement information as well as surface deformation of porcine liver for in vivo probing tasks. In addition, the system is capable of accurately determining the geometry of the liver specimen. These combined attributes provide the context required to simulate the experiment with accurate boundary conditions, whereby the only variable in the analysis is the material properties of the liver specimen. During the simulation, effects of settling due to gravity have been taken into account by a technique which incorporates the proper internal stress conditions in the model without altering the geometry. Initially, an Ogden model developed from ex vivo tension and compression experimentation is run through the simulation to determine the efficacy of utilizing an ex vivo model for simulation of in vivo probing tasks on porcine liver. Subsequently, a method for improving upon the ex vivo model was developed using different hyperelastic models such that increased accuracy could be achieved for the force characteristics compared to the displacement characteristics, since changes in the force variation would be more perceptible to a user in the simulation environment, while maintaining a high correlation with the surface displacement data. Furthermore, this study also presents the probing simulation which includes the capsule surrounding the liver. PMID:21161684

Lister, Kevin; Gao, Zhan; Desai, Jaydev P

2011-03-01

98

Application of XRF to measure strontium in human bone in vivo  

SciTech Connect

As a basis for better understanding the role that Sr fulfills in human body, it is desirable to measure directly the main Sr store in human body. Although strontium is omnipresent in human tissues, 99% is stored inthe mineral portion of the bone. In the present study x-ray fluorescence (XRF) was applied to measure the strontium content of the tibial shaft in vivo. The feasibility studies showed that normal levels of stable strontium in the bone can be measured successfully.

Wielopolski, L.; Vartsky, D.; Yasumura, S.; Cohn, S.H.

1982-01-01

99

In Vivo Activities of Amoxicillin and Amoxicillin-Clavulanate against Streptococcus pneumoniae: Application to Breakpoint Determinations  

Microsoft Academic Search

The in vivo activities of amoxicillin and amoxicillin-clavulanate against 17 strains of Streptococcus pneu- moniae with penicillin MICs of 0.12-8.0 mg\\/liter were assessed in a cyclophosphamide-induced neutropenic murine thigh infection model. Renal impairment was produced by administration of uranyl nitrate to prolong the amoxicillin half-life in the mice from 21 to 65 min, simulating human pharmacokinetics. Two hours after thigh

D. ANDES; W. A. CRAIG

1998-01-01

100

The application of dermal papillary rings in dermatology by in vivo confocal laser scanning microscopy  

Microsoft Academic Search

Confocal laser scanning microscopy (CLSM) allows noninvasive visualization of human skin in vivo, without needing to fix or\\u000a section the tissue. Melanocytes and pigmented keratinocytes at the level of the basal layer form bright dermal papillary rings\\u000a which are readily amenable to identify in confocal images. Our purpose was to explore the role of dermal papillary rings in\\u000a assessment of

W. Z. Xiang; A. E. Xu; J. Xu; Z. G. Bi; Y. B. Shang; Q. S. Ren

2010-01-01

101

In vivo evaluation of a mechanically oscillating dual-mode applicator for ultrasound imaging and thermal ablation.  

PubMed

Unresectable liver tumors are often treated with interstitial probes that modify tissue temperature, and efficacious treatment relies on image guidance for tissue targeting and assessment. Here, we report the in vivo evaluation of an interstitial applicator with a mechanically oscillating five-element dual-mode transducer. After thoroughly characterizing the transducer, tissue response to high-intensity ultrasound was numerically calculated to select parameters for experimentation in vivo. Using perfused porcine liver, B-mode sector images were formed before and after a 120-s therapy period, and M-mode imaging monitored the therapy axis during therapy. The time-averaged transducer surface intensity was 21 or 27 W/cm (2). Electroacoustic conversion efficiency was maximally 72 +/- 3% and impulse response length was 295 +/- 1.0 ns at -6 dB. The depth of thermal damage measured by gross histology ranged from 10 to 25 mm for 13 insertion sites. For six sites, M-mode data exhibited a reduction in gray-scale intensity that was interpreted as the temporal variation of coagulation necrosis. Contrast ratio analysis indicated that the gray-scale intensity dropped by 7.8 +/- 3.3 dB, and estimated the final lesion depth to an accuracy of 2.3 +/- 2.4 mm. This paper verified that the applicator could induce coagulation necrosis in perfused liver and demonstrated the feasibility of real-time monitoring. PMID:19497808

Owen, Neil R; Bouchoux, Guillaume; Seket, Belhassen; Murillo-Rincon, Adriana; Merouche, Samir; Birer, Alain; Paquet, Christian; Delabrousse, Eric; Chapelon, Jean-Yves; Berriet, Rémi; Fleury, Gérard; Lafon, Cyril

2010-01-01

102

Monoclonal antibodies reactive with human breast or ovarian carcinoma: In vivo applications  

SciTech Connect

Monoclonal antibodies (MoAbs) are unique and useful bioprobes that allow in vivo targeting of membrane-associated or circulating antigens. Most of the clinical trials to date have used low dosages of radiolabeled MoAb given in a single dose. Newer studies have included antibody fragments, repeated injections, intraperitoneal (IP) administration, and other labels such as 90Y. Clinical MoAb trials are often arduous, expensive, and time-consuming to perform. Before human use, animal studies and extensive MoAb characterization are required. The production of pharmaceutical grade, radiolabeled MoAb is technically difficult and costly. Clinical trials require administrative and patient consent as well as extensive written protocols. These studies necessitate interdepartmental and intradepartmental cooperation and coordination. Furthermore, the use of in vivo radiolabeled probes impacts many levels of health care providers from janitorial, nursing, and technical staff to laboratories and physicians. Simple blood tests or disposal of body excretions may concern nursing or technical staff with the possibility of radiation exposure. The responsibility for study design, personnel involvement, and prospective use in patients without a definitive cancer diagnosis ultimately rests with the physician. While many issues have been addressed, additional clinical trials, consideration of safety issues, and standardization between institutions will be necessary before the use of radiolabeled MoAb for diagnosis, management, or therapy of human tumors becomes routine. Continued cooperation and funding should ensure its achievement. 136 references.

Thor, A.D.; Edgerton, S.M. (Harvard Medical School, Boston, MA (USA))

1989-10-01

103

Application of resonant cavity perturbation to in vivo segmental hydration measurement  

NASA Astrophysics Data System (ADS)

The dielectric properties of biological tissues at radio and microwave frequencies are strongly correlated with tissue water content. Localized, in vivo measurement of permittivity and conductivity should therefore provide useful clinical information in diseases involving abnormal hydration, such as lymphoedema. We have developed an open-geometry sensor for segmental hydration studies based on a flat cavity resonator operating at 300 MHz, and have demonstrated that the changes in its resonant frequency and Q-factor were significantly greater when it was applied to a swollen, oedematous finger, compared to an uninjured finger of similar size. The resonant sensor was calibrated with reference liquids in vials inserted through holes in its cavity plates, and we found that a modified resonant cavity perturbation formula, with coefficients empirically optimized by means of a genetic algorithm, yielded good agreement with literature values of complex permittivity. However, extending the length of the sample containers leads to measurement artefacts owing to antenna currents with associated radiated energy losses. A detailed simulation of the system with a full-wave solver using Method-of-Moments enabled us to estimate the current distribution and energy balance, and thus take steps towards mitigating these effects and enabling the system to make quantitative in vivo measurements of tissue dielectric properties.

Robinson, M. P.; Flintoft, I. D.; Dawson, L.; Clegg, J.; Truscott, J. G.; Zhu, X.

2010-01-01

104

Application of In Vivo Induced Antigen Technology (IVIAT) to Bacillus anthracis  

PubMed Central

In vivo induced antigen technology (IVIAT) is an immuno-screening technique that identifies bacterial antigens expressed during infection and not during standard in vitro culturing conditions. We applied IVIAT to Bacillus anthracis and identified PagA, seven members of a N-acetylmuramoyl-L-alanine amidase autolysin family, three P60 family lipoproteins, two transporters, spore cortex lytic protein SleB, a penicillin binding protein, a putative prophage holin, respiratory nitrate reductase NarG, and three proteins of unknown function. Using quantitative real-time PCR comparing RNA isolated from in vitro cultured B. anthracis to RNA isolated from BALB/c mice infected with virulent Ames strain B. anthracis, we confirmed induced expression in vivo for a subset of B. anthracis genes identified by IVIAT, including L-alanine amidases BA3767, BA4073, and amiA (pXO2-42); the bacteriophage holin gene BA4074; and pagA (pXO1-110). The exogenous addition of two purified putative autolysins identified by IVIAT, N-acetylmuramoyl-L-alanine amidases BA0485 and BA2446, to vegetative B. anthracis cell suspensions induced a species-specific change in bacterial morphology and reduction in viable bacterial cells. Many of the proteins identified in our screen are predicted to affect peptidoglycan re-modeling, and our results support significant cell wall structural remodeling activity during B. anthracis infection. Identification of L-alanine amidases with B. anthracis specificity may suggest new potential therapeutic targets. PMID:18350160

Rollins, Sean M.; Peppercorn, Amanda; Young, John S.; Drysdale, Melissa; Baresch, Andrea; Bikowski, Margaret V.; Ashford, David A.; Quinn, Conrad P.; Handfield, Martin; Hillman, Jeffrey D.; Lyons, C. Rick; Koehler, Theresa M.; Calderwood, Stephen B.; Ryan, Edward T.

2008-01-01

105

Rapid (18)F-labeling and loading of PEGylated gold nanoparticles for in vivo applications.  

PubMed

Water-soluble 3 nm maleimide-terminated PEGylated gold nanoparticles (maleimide-AuNP) were synthesized in both partially hydrolyzed and nonhydrolyzed forms. Both of these maleimide-AuNPs, when reacted with the silicon-fluorine prosthetic group [(18)F]SiFA-SH, resulted in radiolabeled AuNPs. These NPs were readily purified with high radiochemical yields (RCY) of 60-80% via size exclusion chromatography. Preliminary small animal positron emission tomography (PET) measurements in healthy rats gives information about the pathway of excretion and the stability of the radioactive label in vivo. The partially hydrolyzed [(18)F]SiFA-maleimide-AuNPs shows uptake in the brain region of interest (ROI) (> 0.13%ID/g) which was confirmed by ex vivo examination of the thoroughly perfused rat brain. The multiple maleimide end groups on the AuNP surface also allows for the simultaneous incorporation of [(18)F]SiFA-SH and a bioactive peptide (cysteine-modified octreotate, cys-TATE, which can bind to somatostatin receptor subtypes 2 and 5) in a proof-of-concept study. The well-defined Michael addition reaction between various thiol containing molecules and the multifunctionalized maleimide-AuNPs thus offers an opportunity to develop a new bioconjugation platform for new diagnostics as well as therapeutics. PMID:24807200

Zhu, Jun; Chin, Joshua; Wängler, Carmen; Wängler, Bjoern; Lennox, R Bruce; Schirrmacher, Ralf

2014-06-18

106

Application of laser scan microscopy in vivo for wound healing characterization  

NASA Astrophysics Data System (ADS)

Considering the advancing age of the population, wound healing disturbances are becoming increasingly important in clinical routine. The development of wound healing creams and lotions as well as therapy control require an objective evaluation of the wound healing process, which represents the destruction of the barrier. Therefore, transepidermal water loss measurements are often carried out. These measurements have the disadvantage that they are disturbed by the interstitial fluid, which is located on the surface of chronic wounds and also by water components of the creams and lotions. Additionally, the TEWL measurements are very sensitive to temperature changes and to the anxiety of the volunteers. In the present study, in vivo laser scanning microscopy was used to analyze the reepithelialization and barrier recovery of standardized wounds produced by the suction blister technique. It was demonstrated that this non-invasive, on-line spectroscopic method allows the evaluation of the wound healing process, without any disturbances. It was found that the wound healing starts not only from the edges of the wound, but also out of the hair follicles. The in vivo laser scanning microscopy is well suited to evaluate the efficacy of wound healing creams and for therapy control.

Czaika, V.; Alborova, A.; Sterry, W.; Lademann, J.; Koch, S.

2010-09-01

107

In vitro & in vivo studies on lornoxicam loaded nanoemulsion gels for topical application.  

PubMed

The objective of this work was to increase the solubility, in vitro skin permeability of lornoxicam from semisolid topical formulations and also to investigate the in vivo potential of nanoemulsion formulation. Optimized lornoxicam loaded nanoemulsion was prepared successfully by spontaneous self-emulsification method and the size of the stable formulations was found within the range of 102 to 200 nm. The stable nanoemulsion formulations characterized for viscosity, droplet size, transmission electron microscopy (TEM) and refractive index. In vitro permeation rate of nanoemulsion and conventional gel of lornoxicam (LX) were determined. Prmeability parameters like steady-state flux (Jss), permeability coefficient (Kp), and enhancement ratio (Er) were significantly increased in nanoemulsion NE8 and the nanogel NG8 as compared to conventional gel (LG). In vivo studies revealed a significant increase in anti-inflammatory effects as compared with conventional gel of LX. The anti-inflammatory effects of formulation NG8 showed a significant increase in percent inhibition value when compared with control, this difference was found to be highly significant (p<0.001). This work shows for the first time that lornoxicam can be formulated into nanoemulsions and may show promise in enhancing solubility and permeation. PMID:24266509

Dasgupta, Sandipan; Ghosh, Surajit K; Ray, Subhabrata; Kaurav, Surendra Singh; Mazumder, Bhaskar

2014-01-01

108

In vivo performance of a phospholipid-coated bioerodable elastomeric graft for small-diameter vascular applications  

PubMed Central

There remains a great need for vascular substitutes for small-diameter applications. The use of an elastomeric biodegradable material, enabling acute antithrombogenicity and long-term in vivo remodeling, could be beneficial for this purpose. Conduits (1.3 mm internal diameter) were obtained by electrospinning biodegradable poly(ester urethane)urea (PEUU), and by luminally immobilizing a non-thrombogenic, 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer. Platelet adhesion was characterized in vitro after contact with ovine blood. The conduits were implanted as aortic interposition grafts in the rat for 4, 8, 12, and 24 weeks. Surface treatment resulted in a 10-fold decrease in platelet adhesion compared to untreated material. Patency at 8 weeks was 92% for the coated grafts compared to 40% for the non-coated grafts. Histology at 8 and 12 weeks demonstrated formation of cellularized neotissue consisting of aligned collagen and elastin. The lumen of the grafts was confluent with cells qualitatively aligned in the direction of blood flow. Immunohistochemistry suggested the presence of smooth muscle cells in the medial layer of the neotissue and endothelial cells lining the lumen. Mechanically, the grafts were less compliant than rat aortas prior to implantation (4.5 ± 2.0 × 10–4 mmHg–1 vs. 14.2 ± 1.1 × 10–4 mmHg–1, respectively), then after 4 weeks in vivo they approximated native values, but subsequently became stiffer again at later time points. The novel coated grafts exhibited promising antithrombogenic and mechanical properties for small-diameter arterial revascularization. Further evaluation in vivo will be required to demonstrate complete remodeling of the graft into a native-like artery. PMID:21171163

Soletti, Lorenzo; Nieponice, Alejandro; Hong, Yi; Ye, Sang-Ho; Stankus, John J.; Wagner, William R.; Vorp, David A.

2011-01-01

109

Facile preparation of zwitterion-stabilized superparamagnetic iron oxide nanoparticles (ZSPIONs) as an MR contrast agent for in vivo applications.  

PubMed

We describe a simple method for synthesizing superparamagnetic nanoparticles (SPIONs) as small, stable contrast agents for magnetic resonance imaging (MRI) based on sulfobetaine zwitterionic ligands. SPIONs synthesized by thermal decomposition were coated with zwitterions to impart water dispersibility and high in vivo stability through the nanoemulsion method. Zwitterion surfactant coating layers are formed easily on oleic acid-stabilized SPIONs via hydrophobic and van der Waals interactions. Our zwitterion-coated SPIONs (ZSPIONs) had ultrathin (?5 nm) coating layers with mean sizes of 12.0 ± 2.5 nm, as measured by dynamic light scattering (DLS). Upon incubation in 1 M NaCl and 10% FBS, the ZSPIONs showed high colloidal stabilities without precipitating, as monitored by DLS. The T2 relaxivity coefficient of the ZSPIONs, obtained by measuring the relaxation rate on the basis of the iron concentration, was 261 mM(-1) s(-1). This value was much higher than that of the commercial T2 contrast agent because of the ultrathin coating layer. Furthermore, we confirmed that ZSPIONs can be used as MR contrast agents for in vivo applications such as tumor imaging and lymph node mapping. PMID:22607014

Kim, Dongkyu; Chae, Min Kyung; Joo, Hyun Jung; Jeong, Il-ha; Cho, Jee-Hyun; Lee, Chulhyun

2012-06-26

110

New labeled derivatives of the neuroprotective peptide colivelin: Synthesis, characterization, and first in vitro and in vivo applications.  

PubMed

Colivelin (CL), first reported in 2005, is the most potent member of the humanin family of neuroprotective peptides with in vitro and in vivo rescuing action against insults associated with Alzheimer's disease (AD). The objective of the present work is the design, synthesis and characterization of specific CL derivatives that can be used as molecular probes in the investigation of the unknown mechanism of CL action. Within this framework, three CL derivatives bearing suitable tags, i.e., the fluorescent moiety FITC, the streptavidin-counterpart biotinyl-group, and the (99m)Tc-radiometal chelating unit dimethylGly-Ser-Cys, were developed and subsequently applied in biological evaluation experiments. Specifically, the FITC-labeled derivative of CL was used in confocal microscopy, where specific binding at the periphery of F11 cells was observed; the biotin-labeled derivative of CL was used in an in-house developed ELISA-type assay, where specific and concentration-dependent binding with the ?-amyloid peptide of AD was shown; finally, the (99m)Tc-radiolabeled derivative of CL was used in in vivo biodistribution studies in healthy Swiss Albino mice, where 0.58% of the radioactivity administered was measured in the mouse brain 2min after injection. The above first successful applications of the CL probes demonstrate their potential to contribute in the field of neuroprotective peptides. PMID:25575783

Kostomoiri, Myrta; Zikos, Christos; Benaki, Dimitra; Triantis, Charalampos; Sagnou, Marina; Paravatou-Petsotas, Maria; Papadaki, Amalia; Boleti, Haralabia; Papadopoulos, Minas; Pirmettis, Ioannis; Pelecanou, Maria; Livaniou, Evangelia

2015-02-01

111

Medical applications of in vivo neutron inelastic scattering and neutron activation analysis: Technical similarities to detection of explosives and contraband  

NASA Astrophysics Data System (ADS)

Nutritional status of patients can be evaluated by monitoring changes in elemental body composition. Fast neutron activation (for N and P) and neutron inelastic scattering (for C and O) are used in vivo to assess elements characteristic of specific body compartments. There are similarities between the body composition techniques and the detection of hidden explosives and narcotics. All samples have to be examined in depth and the ratio of elements provides a "signature" of the chemical of interest. The N/H and C/O ratios measure protein and fat content in the body. Similarly, a high C/O ratio is characteristic of narcotics and a low C/O together with a strong presence of N is a signature of some explosives. The available time for medical applications is about 20 min—compared to a few seconds for the detection of explosives—but the permitted radiation exposure is limited. In vivo neutron analysis is used to measure H, O, C, N, P, Na, Cl, and Ca for the study of the mechanisms of lean tissue depletion with aging and wasting diseases, and to investigate methods of preserving function and quality of life in the elderly.

Kehayias, J. J.

2001-07-01

112

A large preclinical animal model to assess ex vivo skin gene therapy applications  

Microsoft Academic Search

Because of its easy accessibility, the skin is a very attractive target for gene therapy purposes. To study potential clinical applications in a preclinical setting, appropriate animal models are needed. Pig skin is very similar to human skin, and a variety of human diseases that are potentially amenable to gene therapy applications also occur in pigs. Only a few studies

Wolfgang Pfützner; Mohammed R. Joari; Ruth-Ann Foster; Jonathan C. Vogel

2006-01-01

113

A polymer-based neural microimplant for optogenetic applications: design and first in vivo study.  

PubMed

In optogenetics, neurons are genetically modified to become sensitive to light and thus, they can be stimulated or inhibited by light of certain wavelengths. In this work, we describe the fabrication of a polymer-based shaft electrode as a tool for optogenetics. This device can conduct light as well as fluids to a target brain region and record electrical neural signals from the same part of the tissue simultaneously. It is intended to facilitate optogenetic in vivo experiments with those novel multimodal neural probes or polymer optrodes. We used microsystems technology to integrate an SU-8 based waveguide and fluidic channel into a polyimide-based electrode shaft to allow simultaneous optical stimulation, fluid delivery, and electrophysiological recording in awake behaving animals. In a first acute proof-of-concept experiment in genetically modified mice, our device recorded single unit activity that was modulated by laser light transmitted into the tissue via the integrated waveguide. PMID:23306183

Rubehn, Birthe; Wolff, Steffen B E; Tovote, Philip; Lüthi, Andreas; Stieglitz, Thomas

2013-02-21

114

Thermally cross-linked superparamagnetic iron oxide nanoparticles: synthesis and application as a dual imaging probe for cancer in vivo.  

PubMed

We report the fabrication and characterization of thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPION) and their application to the dual imaging of cancer in vivo. Unlike dextran-coated cross-linked iron oxide nanoparticles, which are prepared by a chemical cross-linking method, TCL-SPION are prepared by a simple, thermal cross-linking method using a Si-OH-containing copolymer. The copolymer, poly(3-(trimethoxysilyl)propyl methacrylate-r-PEG methyl ether methacrylate-r-N-acryloxysuccinimide), was synthesized by radical polymerization and used as a coating material for as-synthesized magnetite (Fe3O4) SPION. The polymer-coated SPION was further heated at 80 degrees C to induce cross-linking between the -Si(OH)3 groups in the polymer chains, which finally generated TCL-SPION bearing a carboxyl group as a surface functional group. The particle size, surface charge, presence of polymer-coating layers, and the extent of thermal cross-linking were characterized and confirmed by various measurements, including dynamic light scattering, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The carboxyl TCL-SPION was converted to amine-modified TCL-SPION and then finally to Cy5.5 dye-conjugated TCL-SPION for use in dual (magnetic resonance/optical) in vivo cancer imaging. When the Cy5.5 TCL-SPION was administered to Lewis lung carcinoma tumor allograft mice by intravenous injection, the tumor was unambiguously detected in T2-weighted magnetic resonance images as a 68% signal drop as well as in optical fluorescence images within 4 h, indicating a high level of accumulation of the nanomagnets within the tumor site. In addition, ex vivo fluorescence images of the harvested tumor and other major organs further confirmed the highest accumulation of the Cy5.5 TCL-SPION within the tumor. It is noteworthy that, despite the fact that TCL-SPION does not bear any targeting ligands on its surface, it was highly effective for tumor detection in vivo by dual imaging. PMID:17892287

Lee, Haerim; Yu, Mi Kyung; Park, Sangjin; Moon, Sungmin; Min, Jung Jun; Jeong, Yong Yeon; Kang, Hae-Won; Jon, Sangyong

2007-10-24

115

Development and application of an in vivo plant peroxisome import system.  

PubMed Central

The purposes of this study are to develop an in vivo cell system that is suitable for the immunofluorescent detection of transiently expressed proteins targeted to plant peroxisomes and to determine whether a C-terminal serine-lysine-leucine (SKL) tripeptide, a consensus-targeting signal for mammalian peroxisomes, also targets proteins to plant peroxisomes. Protoplasts from mesophyll cells and from suspension-cultured cells initially were examined for their potential as an in vivo import system. Several were found suitable, but based on a combination of criteria, suspension-cultured tobacco (Nicotiana tabacum L. cv Bright Yellow 2) cells (TBY-2) were chosen. The tobacco cell extracts had catalase activity, and two polypeptides of approximately 55 and 57 kD specifically were detected on immunoblots with anti-cottonseed catalase immunoglobulins G as the probe. Indirect immunofluorescence microscopy with these immunoglobulins G revealed a punctate labeling pattern indicative of endogenous catalase localization within putative TBY-2 peroxisomes. The cells did not have to be completely converted to protoplasts for optimal microscopy; treatment with 0.1% (w/v) pectolyase for 2 h was sufficient. Microprojectile bombardment proved superior for transient transformation of the TBY-2 cells with plasmids encoding beta-glucuronidase, or chloramphenicol acetyltransferase (CAT), or CAT with an added C-terminal tripeptide (CAT-SKL). C-terminal SKL is a consensus, type 1, peroxisome targeting signal. Double indirect immunofluorescent labeling showed that CAT-SKL co-localized with endogenous catalase. Non-punctate, diffuse localization of CAT without SKL provided direct evidence that the C-terminal SKL tripeptide was necessary and sufficient for targeting of CAT to plant peroxisomes. These data demonstrate the effectiveness of this peroxisome targeting signal for plant cells. PMID:7770524

Banjoko, A; Trelease, R N

1995-01-01

116

Application of a partial-thickness human ex vivo skin culture model in cutaneous wound healing study  

Microsoft Academic Search

A number of in vivo and ex vivo skin models have been applied to human wound healing studies. A reliable skin model, which recapitulates the features of human wound repair, is essential for the clinical and mechanical investigation of human cutaneous wound healing. Full-skin ex vivo culture systems have been used in wound healing studies. However, important structures of the

Wei Xu; Seok Jong Hong; Shengxian Jia; Yanan Zhao; Robert D Galiano; Thomas A Mustoe

2012-01-01

117

HPLC determination of novel dithiolethione containing drugs and its application for in vivo studies in rats.  

PubMed

A panel of new drugs obtained by grafting a sulfurated moiety, i.e. 5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione (ADTOH) onto existing drugs have been synthesized and their in vivo action is under preclinical evaluation. In the present paper we describe rapid HPLC methods to detect ADTOH derivatives of valproic acid (ACS2), sildenafil (ACS6), aspirin (ACS14) and diclofenac (ACS15) in plasma. These methods allow the simultaneous detection of the potential drugs and of ADTOH moiety. In the case of ACS14 the de-acetylated metabolite (ACS21) can also be concomitantly measured. The chromatographic separation was performed on a C18 column, applying a mobile phase consisting of a mixture of trifluoroacetic acid and acetonitrile. ADTOH, ACS6, ACS14, ACS21 were separated isocratically whereas ACS2 and ACS15 were separated applying gradient elution. The methods are precise and accurate, with a low quantification limit of 200 nM for ACS2, ACS15 and ACS21 or 100 nM for ADTOH, ACS6 and ACS14. The mean absolute recovery for all tested molecules was always found to be close to 100%. The methods are shown to be selective and linear in the range 0.2-50 microM and thus appear suitable for pharmacokinetic studies with ADTOH containing compounds, as indicated by exemplificative experiments performed with intravenous administration of the drugs to rats. PMID:20006565

Giustarini, Daniela; Perrino, Elena; Tazzari, Valerio; Rossi, Ranieri

2010-02-01

118

Ketorolac tromethamine floating beads for oral application: Characterization and in vitro/in vivo evaluation  

PubMed Central

The floating beads have been employed to make a sustained release of the drug in the stomach and to decrease the dose of the drug and hence overcome its side effects. The common benefits of the floating beads were it is easy preparation, without the need of a high temperature, and high percentage of the drug entrapment. In the present work, the Ketorolac tromethamine (KT) floating beads were prepared by extrusion congealing method utilizing calcium carbonate as a gas forming agent. The physical characters of the produced beads were investigated such as KT yield, KT loading, and entrapment efficiency of the drug. In addition, floating behavior, swelling, particle size, morphology and KT stability were also evaluated. In vitro drug release study was carried out, and the kinetics of the release was evaluated using the linear regression method. Furthermore, the in vivo analgesic effect of KT after oral administration of the selected formula of floating beads (F10) was carried out using hot plate and tail flick methods. Oral commercial KT tablets and KT solution were used for the comparison. The prepared beads remained floated for more than 8 h. The optimized formulation (F10) exhibited prolonged drug release (more than 8 h) and the drug release follows the Higuchi kinetic model, with a Fickian diffusion mechanism according to Korsmeyer-Peppas (n = 0.466). Moreover, F10 showed a sustained analgesic effect as compared to the commercial tablet. PMID:25161380

Abou el Ela, Amal El Sayeh F.; Hassan, Maha A.; El- Maraghy, Dalia A.

2013-01-01

119

Current concepts and new developments for autologous in vivo endothelialisation of biomaterials for intravascular applications.  

PubMed

Circulating endothelial progenitor cells (EPCs) in the peripheral blood of adults represent an auspicious cell source for tissue engineering of an autologous endothelium on blood-contacting implants. Novel materials biofunctionalised with EPC-specific capture molecules represent an intriguing strategy for induction of selective homing of progenitor cells. The trapped EPCs can differentiate into endothelial cells and generate a non-thrombogenic surface on artificial materials. However, the success of this process mainly depends on the use of optimised capture molecules with a high selectivity and affinity. In recent years, various biomedical engineering strategies have emerged for in situ immobilisation of patient's own stem cells on blood contacting materials. The realisation of this in vivo tissue engineering concept and generation of an endothelium on artificial surfaces could exceedingly enhance the performance of not only small calibre vascular grafts and stents, but also, in general all blood-contacting medical devices, such as heart valves, artificial lungs, hearts, kidneys, and ventricular assist devices. PMID:21312162

Avci-Adali, M; Perle, N; Ziemer, G; Wendel, H P

2011-01-01

120

TOPICAL APPLICATION OF BLEACHING PHENOLS; IN VIVO STUDIES AND MECHANISM OF ACTION RELEVANT TO MELANOMA TREATMENT  

PubMed Central

Skin depigmentation represents a well established treatment for extensive vitiligo and may likewise be suited to prevent tumor recurrences and as a prophylactic treatment of familial melanoma, as common bleaching agents are cytotoxic to melanocytes. Effective melanoma prevention requires a bleaching agent-induced loss of exposed melanocytes supported by an immune response to distant pigment cells. Studies on human explant cultures treated with depigmenting agents, 4-tertiary butyl phenol (4-TBP) or monobenzyl ether of hydroquinone (MBEH) revealed a significant increase in the migration of Langerhans cells towards the dermis only upon MBEH treatment thus suggesting selective elicitation of an immune response. To assess the depigmenting potential of bleaching agents in vivo, 4-TBP and MBEH were topically applied to C57BL/6 wild type as well as k14-SCF transgenic, epidermally pigmented mice. MBEH induced significant skin depigmentation in both strains, not observed upon 4-TBP treatment. Cytokine expression patterns in MBEH treated skin support activation of a Th1 mediated immune response corresponding to an influx of T cells and macrophages. Importantly, despite insensitivity of tumor cells to MBEH induced cytotoxicity, significantly retarded tumor growth was observed in B16 challenged k14-SCF mice pretreated with MBEH, likely due to an abundance of cytotoxic T cells accompanied by an increased expression of Th1 and Th17 cytokines. These data support the use of MBEH as a prophylactic treatment for melanoma. PMID:21317816

Hariharan, Vidhya; Toole, Timothy; Klarquist, Jared; Longley, Jack B; Mosenson, Jeffrey; Le Poole1, I. Caroline

2012-01-01

121

Formulation of meloxicam gel for topical application: In vitro and in vivo evaluation.  

PubMed

Skin delivery of NSAIDs offers several advantages over the oral route associated with potential side effects. In the present investigation, topical gel of meloxicam (MLX) was formulated using N-methyl pyrrolidone (NMP) as a solubilizer and Carbopol Ultrez 10® as a gelling polymer. MLX gel was evaluated with respect to different physicochemical parameters such as pH, viscosity and spreadability. Irritation potential of MLX gel was studied on rabbits. Permeation of MLX gel was studied using freshly excised rat skin as a membrane. Anti-inflammatory activity of MLX gel was studied in rats and compared with the commercial formulation of piroxicam (Pirox® gel, 0.5% m/m). Accelerated stability studies were carried out for MLX gel for 6 months according to ICH guidelines. MLX gel was devoid of any skin irritation in rabbits. After 12 h, cumulative permeation of MLX through excised rat skin was 3.0 ± 1.2 mg cm-2 with the corresponding flux value of 0.24 ± 0.09 mg cm-2 h-1. MLX gel exhibited significantly higher anti-inflammatory activity in rats compared to Pirox® gel. Physicochemically stable and non-irritant MLX gel was formulated which could deliver significant amounts of active substance across the skin in vitro and in vivo to elicit the anti-inflammatory activity. PMID:21134852

Bachhav, Yogeshwar G; Patravale, Vandana B

2010-06-01

122

Sphene ceramics for orthopedic coating applications: an in vitro and in vivo study.  

PubMed

The host response to titanium alloy (Ti-6Al-4V) is not always favorable as a fibrous layer may form at the skeletal tissue-device interface, causing aseptic loosening. Recently, sphene (CaTiSiO(5)) ceramics were developed by incorporating Ti in the Ca-Si system, and found to exhibit improved chemical stability. The aim of this study is to evaluate the in vitro response of human osteoblast-like cells, human osteoclasts and human microvascular endothelial cells to sphene ceramics and determine whether coating Ti-6Al-4V implants with sphene enhances anchorage to surrounding bone. The study showed that sphene ceramics support human osteoblast-like cell attachment with organized cytoskeleton structure and express increased mRNA levels of osteoblast-related genes. Sphene ceramics were able to induce the differentiation of monocytes to form functional osteoclasts with the characteristic features of f-actin and alpha(v)beta(3) integrin, and express osteoclast-related genes. Human endothelial cells were also able to attach and express the endothelial cell markers ZO-1 and VE-Cadherin when cultured on sphene ceramics. Histological staining, enzyme histochemistry and immunolabelling were used for identification of mineralized bone and bone remodelling around the coated implants. Ti-6Al-4V implants coated with sphene showed new bone formation and filled the gap between the implants and existing bone in a manner comparable to that of the hydroxyapatite coatings used as control. The new bone was in direct contact with the implants, whereas fibrous tissue formed between the bone and implant with uncoated Ti-6Al-4V. The in vivo assessment of sphene-coated implants supports our in vitro observation and suggests that they have the ability to recruit osteogenic cells, and thus support bone formation around the implants and enhance osseointegration. PMID:19457458

Ramaswamy, Yogambha; Wu, Chengtie; Dunstan, Colin R; Hewson, Benjamin; Eindorf, Tanja; Anderson, Gail I; Zreiqat, Hala

2009-10-01

123

Nanomiemgel - A Novel Drug Delivery System for Topical Application - In Vitro and In Vivo Evaluation  

PubMed Central

Aim The objective of this study was to formulate and evaluate a unique matrix mixture (nanomiemgel) of nanomicelle and nanoemulsion containing aceclofenac and capsaicin using in vitro and in vivo analyses and to compare it to a marketed formulation (Aceproxyvon). Methods Nanomicelles were prepared using Vitamin E TPGS by solvent evaporation method and nanoemulsion was prepared by high-pressure homogenization method. In vitro drug release and human skin permeation studies were performed and analyzed using HPLC. The efficiency of nanomiemgel as a delivery system was investigated using an imiquimod-induced psoriatic like plaque model developed in C57BL/6 mice. Results Atomic Force Microscopy images of the samples exhibited a globular morphology with an average diameter of 200, 250 and 220 nm for NMI, NEM and NMG, respectively. Nanomiemgel demonstrated a controlled release drug pattern and induced 2.02 and 1.97-fold more permeation of aceclofenac and capsaicin, respectively than Aceproxyvon through dermatomed human skin. Nanomiemgel also showed 2.94 and 2.09-fold greater Cmax of aceclofenac and capsaicin, respectively than Aceproxyvon in skin microdialysis study in rats. The PASI score, ear thickness and spleen weight of the imiquimod-induced psoriatic-like plaque model were significantly (p<0.05) reduced in NMG treated mice compared to free drug, NEM, NMI & Aceproxyvon. Conclusion Using a new combination of two different drug delivery systems (NEM+NMI), the absorption of the combined system (NMG) was found to be better than either of the individual drug delivery systems due to the utilization of the maximum possible paths of absorption available for that particular drug. PMID:25546392

Somagoni, Jaganmohan; Boakye, Cedar H. A.; Godugu, Chandraiah; Patel, Apurva R.; Mendonca Faria, Henrique Antonio; Zucolotto, Valtencir; Singh, Mandip

2014-01-01

124

Modulating Gold Nanoparticle in vivo Delivery for Photothermal Therapy Applications Using a T Cell Delivery System  

NASA Astrophysics Data System (ADS)

This thesis reports new gold nanoparticle-based methods to treat chemotherapy-resistant and metastatic tumors that frequently evade conventional cancer therapies. Gold nanoparticles represent an innovative generation of diagnostic and treatment agents due to the ease with which they can be tuned to scatter or absorb a chosen wavelength of light. One area of intensive investigation in recent years is gold nanoparticle photothermal therapy (PTT), in which gold nanoparticles are used to heat and destroy cancer. This work demonstrates the utility of gold nanoparticle PTT against two categories of cancer that are currently a clinical challenge: trastuzumab-resistant breast cancer and metastatic cancer. In addition, this thesis presents a new method of gold nanoparticle delivery using T cells that increases gold nanoparticle tumor accumulation efficiency, a current challenge in the field of PTT. I ablated trastuzumab-resistant breast cancer in vitro for the first time using anti-HER2 labeled silica-gold nanoshells, demonstrating the potential utility of PTT against chemotherapy-resistant cancers. I next established for the first time the use of T cells as gold nanoparticle vehicles in vivo. When incubated with gold nanoparticles in culture, T cells can internalize up to 15000 nanoparticles per cell with no detrimental effects to T cell viability or function (e.g. migration and cytokine secretion). These AuNP-T cells can be systemically administered to tumor-bearing mice and deliver gold nanoparticles four times more efficiently than by injecting free nanoparticles. In addition, the biodistribution of AuNP-T cells correlates with the normal biodistribution of T cell carrier, suggesting the gold nanoparticle biodistribution can be modulated through the choice of nanoparticle vehicle. Finally, I apply gold nanoparticle PTT as an adjuvant treatment for T cell adoptive transfer immunotherapy (Hyperthermia-Enhanced Immunotherapy or HIT) of distant tumors in a melanoma mouse model. The results presented in this thesis expand the potential of gold nanoparticle PTT from only chemotherapy-sensitive or localized cancers to chemotherapy-resistant non-localized cancers that currently defy conventional therapies.

Kennedy, Laura Carpin

125

{ital In vivo} local determination of tissue optical properties: applications to human brain  

SciTech Connect

Local and superficial near-infrared (NIR) optical-property characterization of turbid biological tissues can be achieved by measurement of spatially resolved diffuse reflectance at small source{endash}detector separations ({lt}1.4 mm). However, in these conditions the inverse problem, i.e., calculation of localized absorption and the reduced scattering coefficients, is necessarily sensitive to the scattering phase function. This effect can be minimized if a new parameter of the phase function {gamma}, which depends on the first and the second moments of the phase function, is known. If {gamma} is unknown, an estimation of this parameter can be obtained by the measurement, but the uncertainty of the absorption coefficient is increased. A spatially resolved reflectance probe employing multiple detector fibers (0.3{endash}1.4 mm from the source) is described. Monte Carlo simulations are used to determine {gamma}, the reduced scattering and absorption coefficients from reflectance data. Probe performance is assessed by measurements on phantoms, the optical properties of which were measured by other techniques [frequency domain photon migration (FDPM) and spatially resolved transmittance]. Our results show that changes in the absorption coefficient, the reduced scattering coefficient, and {gamma} can be measured to within {plus_minus}0.005 mm{sup {minus}1}, {plus_minus}0.05 mm{sup {minus}1}, and {plus_minus}0.2, respectively. {ital In vivo} measurements performed intraoperatively on a human skull and brain are reported for four NIR wavelengths (674, 811, 849, 956 nm) when the spatially resolved probe and FDPM are used. The spatially resolved probe shows optimum measurement sensitivity in the measurement volume immediately beneath the probe (typically 1 mm{sup 3} in tissues), whereas FDPM typically samples larger regions of tissues. Optical-property values for human skull, white matter, scar tissue, optic nerve, and tumors are reported that show distinct absorption and scattering differences between structures and a dependence on the phase-function parameter {gamma}. {copyright} 1999 Optical Society of America

Bevilacqua, F.; Piguet, D.; Marquet, P.; Depeursinge, C. [Department of Micro-Engineering, institute of Applied Optics, Swiss Federal Institute of Technology Lausanne, 1015 Lausanne (Switzerland); Gross, J.D.; Tromberg, B.J. [Laser Microbeam and Medical Program, Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612 (United States)

1999-08-01

126

Biological effects of low frequency high intensity ultrasound application on ex vivo human adipose tissue.  

PubMed

In the present work the effects of a new low frequency, high intensity ultrasound technology on human adipose tissue ex vivo were studied. In particular, we investigated the effects of both external and surgical ultrasound-irradiation (10 min) by evaluating, other than sample weight loss and fat release, also histological architecture alteration as well apoptosis induction. The influence of saline buffer tissue-infiltration on the effects of ultrasound irradiation was also examined. The results suggest that, in our experimental conditions, both transcutaneous and surgical ultrasound exposure caused a significant weight loss and fat release. This effect was more relevant when the ultrasound intensity was set at 100 % (~2.5 W/cm², for external device; ~19-21 W/cm2, for surgical device) compared to 70 % (~1.8 W/cm² for external device; ~13-14 W/cm2 for surgical device). Of note, the effectiveness of ultrasound was much higher when the tissue samples were previously infiltrated with saline buffer, in accordance with the knowledge that ultrasonic waves in aqueous solution better propagate with a consequently more efficient cavitation process. Moreover, the overall effects of ultrasound irradiation did not appear immediately after treatment but persisted over time, being significantly more relevant at 18 h from the end of ultrasound irradiation. Evaluation of histological characteristics of ultrasound-irradiated samples showed a clear alteration of adipose tissue architecture as well a prominent destruction of collagen fibers which were dependent on ultrasound intensity and most relevant in saline buffer-infiltrated samples. The structural changes of collagen bundles present between the lobules of fat cells were confirmed through scanning electron microscopy (SEM) which clearly demonstrated how ultrasound exposure induced a drastic reduction in the compactness of the adipose connective tissue and an irregular arrangement of the fibers with a consequent alteration in the spatial architecture. The analysis of the composition of lipids in the fat released from adipose tissue after ultrasound treatment with surgical device showed, in agreement with the level of adipocyte damage, a significant increase mainly of triglycerides and cholesterol. Finally, ultrasound exposure had been shown to induce apoptosis as shown by the appearance DNA fragmentation. Accordingly, ultrasound treatment led to down-modulation of procaspase-9 expression and an increased level of caspase-3 active form. PMID:21658315

Palumbo, P; Cinque, B; Miconi, G; La Torre, C; Zoccali, G; Vrentzos, N; Vitale, A R; Leocata, P; Lombardi, D; Lorenzo, C; D'Angelo, B; Macchiarelli, G; Cimini, A; Cifone, M G; Giuliani, M

2011-01-01

127

Transurethral ultrasound applicators with dynamic multi-sector control for prostate thermal therapy: in vivo evaluation under MR guidance.  

PubMed

The purpose of this study was to explore the feasibility and performance of a multi-sectored tubular array transurethral ultrasound applicator for prostate thermal therapy, with potential to provide dynamic angular and length control of heating under MR guidance without mechanical movement of the applicator. Test configurations were fabricated, incorporating a linear array of two multi-sectored tubular transducers (7.8-8.4 MHz, 3 mm OD, 6 mm length), with three 120 degrees independent active sectors per tube. A flexible delivery catheter facilitated water cooling (100 ml min(-1)) within an expandable urethral balloon (35 mm long x 10 mm diameter). An integrated positioning hub allows for rotating and translating the transducer assembly within the urethral balloon for final targeting prior to therapy delivery. Rotational beam plots indicate approximately 90 degrees-100 degrees acoustic output patterns from each 120 degrees transducer sector, negligible coupling between sectors, and acoustic efficiencies between 41% and 53%. Experiments were performed within in vivo canine prostate (n = 3), with real-time MR temperature monitoring in either the axial or coronal planes to facilitate control of the heating profiles and provide thermal dosimetry for performance assessment. Gross inspection of serial sections of treated prostate, exposed to TTC (triphenyl tetrazolium chloride) tissue viability stain, allowed for direct assessment of the extent of thermal coagulation. These devices created large contiguous thermal lesions (defined by 52 degrees C maximum temperature, t43 = 240 min thermal dose contours, and TTC tissue sections) that extended radially from the applicator toward the border of the prostate (approximately15 mm) during a short power application (approximately 8-16 W per active sector, 8-15 min), with approximately 200 degrees or 360 degrees sector coagulation demonstrated depending upon the activation scheme. Analysis of transient temperature profiles indicated progression of lethal temperature and thermal dose contours initially centered on each sector that coalesced within approximately 5 min to produce uniform and contiguous zones of thermal destruction between sectors, with smooth outer boundaries and continued radial propagation in time. The dimension of the coagulation zone along the applicator was well-defined by positioning and active array length. Although not as precise as rotating planar and curvilinear devices currently under development for MR-guided procedures, advantages of these multi-sectored transurethral applicators include a flexible delivery catheter and that mechanical manipulation of the device using rotational motors is not required during therapy. This multi-sectored tubular array transurethral ultrasound technology has demonstrated potential for relatively fast and reasonably conformal targeting of prostate volumes suitable for the minimally invasive treatment of BPH and cancer under MR guidance, with further development warranted. PMID:18561684

Kinsey, Adam M; Diederich, Chris J; Rieke, Viola; Nau, William H; Pauly, Kim Butts; Bouley, Donna; Sommer, Graham

2008-05-01

128

Transurethral ultrasound applicators with dynamic multi-sector control for prostate thermal therapy: In vivo evaluation under MR guidance  

SciTech Connect

The purpose of this study was to explore the feasibility and performance of a multi-sectored tubular array transurethral ultrasound applicator for prostate thermal therapy, with potential to provide dynamic angular and length control of heating under MR guidance without mechanical movement of the applicator. Test configurations were fabricated, incorporating a linear array of two multi-sectored tubular transducers (7.8-8.4 MHz, 3 mm OD, 6 mm length), with three 120 deg. independent active sectors per tube. A flexible delivery catheter facilitated water cooling (100 ml min{sup -1}) within an expandable urethral balloon (35 mm longx10 mm diameter). An integrated positioning hub allows for rotating and translating the transducer assembly within the urethral balloon for final targeting prior to therapy delivery. Rotational beam plots indicate {approx}90 deg. - 100 deg. acoustic output patterns from each 120 deg. transducer sector, negligible coupling between sectors, and acoustic efficiencies between 41% and 53%. Experiments were performed within in vivo canine prostate (n=3), with real-time MR temperature monitoring in either the axial or coronal planes to facilitate control of the heating profiles and provide thermal dosimetry for performance assessment. Gross inspection of serial sections of treated prostate, exposed to TTC (triphenyl tetrazolium chloride) tissue viability stain, allowed for direct assessment of the extent of thermal coagulation. These devices created large contiguous thermal lesions (defined by 52 deg. C maximum temperature, t{sub 43}=240 min thermal dose contours, and TTC tissue sections) that extended radially from the applicator toward the border of the prostate ({approx}15 mm) during a short power application ({approx}8-16 W per active sector, 8-15 min), with {approx}200 deg. or 360 deg. sector coagulation demonstrated depending upon the activation scheme. Analysis of transient temperature profiles indicated progression of lethal temperature and thermal dose contours initially centered on each sector that coalesced within {approx}5 min to produce uniform and contiguous zones of thermal destruction between sectors, with smooth outer boundaries and continued radial propagation in time. The dimension of the coagulation zone along the applicator was well-defined by positioning and active array length. Although not as precise as rotating planar and curvilinear devices currently under development for MR-guided procedures, advantages of these multi-sectored transurethral applicators include a flexible delivery catheter and that mechanical manipulation of the device using rotational motors is not required during therapy. This multi-sectored tubular array transurethral ultrasound technology has demonstrated potential for relatively fast and reasonably conformal targeting of prostate volumes suitable for the minimally invasive treatment of BPH and cancer under MR guidance, with further development warranted.

Kinsey, Adam M.; Diederich, Chris J.; Rieke, Viola; Nau, William H.; Pauly, Kim Butts; Bouley, Donna; Sommer, Graham [Thermal Therapy Research Group, Department of Radiation Oncology, University of California, San Francisco, California 94143 (United States) and Joint Graduate Group in Bioengineering, University of California, Berkeley and San Francisco, California 94158 (United States); Department of Radiology, Stanford University Medical Center, Stanford, California 94305 (United States); Thermal Therapy Research Group, Department of Radiation Oncology, University of California, San Francisco, California 94143 (United States); Department of Radiology, Stanford University Medical Center, Stanford, California 94305 (United States); Department of Comparative Medicine, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Stanford University Medical Center, Stanford, California 94305 (United States)

2008-05-15

129

Transurethral ultrasound applicators with directional heating patterns for prostate thermal therapy: in vivo evaluation using magnetic resonance thermometry.  

PubMed

A catheter-based transurethral ultrasound applicator with angularly directional heating patterns has been designed for prostate thermal therapy and evaluated in canine prostate in vivo using MRI to monitor and assess performance. The ultrasound transducer array (3.5 mm diameter tubular transducers, 180 degrees active sectors, approximately 7.5 MHz) was integrated to a flexible delivery catheter (4 mm OD), and encapsulated within an expandable balloon (35 mm x 10 mm OD, 80 ml min(-1) ambient water) for coupling and cooling of the prostatic urethra. These devices were used to thermally coagulate targeted portions of the canine prostate (n = 2) while using MR thermal imaging (MRTI) to monitor the therapy. MRI was also used for target definition, positioning of the applicator, and evaluation of target viability post-therapy. MRTI was based upon the complex phase-difference mapping technique using an interleaved gradient echo-planar imaging sequence with lipid suppression. MRTI derived temperature distributions, thermal dose exposures, T1-contrast enhanced MR images, and histology of sectioned prostates were used to define destroyed tissue zones and characterize the three-dimensional heating patterns. The ultrasound applicators produced approximately 180 degrees directed zones of thermal coagulation within targeted tissue which extended 15-20 mm radially to the outer boundary of the prostate within 15 min. Transducer activation lengths of 17 mm and 24 mm produced contiguous zones of coagulation extending axially approximately 18 mm and approximately 25 mm from base to apex, respectively. Peak temperatures around 90 degrees C were measured, with approximately 50 degrees C-52 degrees C corresponding to outer boundary t43 = 240 min at approximately 15 min treatment time. These devices are MRI compatible, and when coupled with multiplanar MRTI provide a means for selectively controlling the length and sector angle of therapeutic thermal treatment in the prostate. PMID:15000627

Diederich, C J; Stafford, R J; Nau, W H; Burdette, E C; Price, R E; Hazle, J D

2004-02-01

130

Recent advances in in vivo applications of intein-mediated protein splicing  

PubMed Central

Intein-mediated protein splicing has become an essential tool in modern biotechnology. Fundamental progress in the structure and catalytic strategies of cis- and trans-splicing inteins has led to the development of modified inteins that promote efficient protein purification, ligation, modification and cyclization. Recent work has extended these in vitro applications to the cell or to whole organisms. We review recent advances in intein-mediated protein expression and modification, post-translational processing and labeling, protein regulation by conditional protein splicing, biosensors, and expression of trans-genes. PMID:24490831

2014-01-01

131

A simple and widely applicable method to 59Fe-radiolabel monodisperse superparamagnetic iron oxide nanoparticles for in vivo quantification studies.  

PubMed

A simple, fast, efficient, and widely applicable method to radiolabel the cores of monodisperse superparamagnetic iron oxide nanoparticles (SPIOs) with (59)Fe was developed. These cores can be used as precursors for a variety of functionalized nanodevices. A quality control using filtration techniques, size-exclusion chromatography, chemical degradation methods, transmission electron microscopy, and magnetic resonance imaging showed that the nanoparticles were stably labeled with (59)Fe. Furthermore, the particle structure and the magnetic properties of the SPIOs were unchanged. In a second approach, monodisperse SPIOs stabilized with (14)C-oleic acid were synthesized, and the stability of this shell labeling was studied. In proof of principle experiments, the (59)Fe-SPIOs coated with different shells to make them water-soluble were used to evaluate and compare in vivo pharmacokinetic parameters such as blood half-life. It could also be shown that our radiolabeled SPIOs embedded in recombinant lipoproteins can be used to quantify physiological processes in closer detail than hitherto possible. In vitro and in vivo experiments showed that the (59)Fe label is stable enough to be applied in vivo, whereas the (14)C label is rapidly removed from the iron core and is not adequate for in vivo studies. To obtain meaningful results in in vivo experiments, only (59)Fe-labeled SPIOs should be used. PMID:22793497

Freund, Barbara; Tromsdorf, Ulrich I; Bruns, Oliver T; Heine, Markus; Giemsa, Artur; Bartelt, Alexander; Salmen, Sunhild C; Raabe, Nina; Heeren, Joerg; Ittrich, Harald; Reimer, Rudolph; Hohenberg, Heinrich; Schumacher, Udo; Weller, Horst; Nielsen, Peter

2012-08-28

132

First in vivo application and evaluation of a novel method for non-invasive estimation of cardiac output.  

PubMed

Surgical or critically ill patients often require continuous assessment of cardiac output (CO) for diagnostic purposes or for guiding therapeutic interventions. A new method of non-invasive CO estimation has been recently developed, which is based on pressure wave analysis. However, its validity has been examined only in silico. Aim of this study was to evaluate in vivo the reproducibility and accuracy of the "systolic volume balance" method (SVB). Twenty two subjects underwent 2-D transthoracic echocardiography for CO measurement (reference value of CO). The application of SVB method required aortic pressure wave analysis and estimation of total arterial compliance. Aortic pulses were derived by mathematical transformation of radial pressure waves recorded by applanation tonometry. Total compliance was estimated by the "pulse pressure" method. The agreement, association, variability, bias and precision between Doppler and SVB measures of CO were evaluated by intraclass correlation coefficient (ICC), mean difference, SD of differences, percentage error (PR) and Bland-Altman analysis. SVB yielded very reproducible CO estimates (ICC=0.84, mean difference 0.27 ± 0.73 L/min, PR = 16.7%). SVB-derived CO was comparable with Doppler measurements, indicating a good agreement and accuracy (ICC = 0.74, mean difference = -0.22 ± 0.364 L/min, PR ? 15). The basic mathematical and physical principles of the SVB method provide highly reproducible and accurate estimates of CO compared with echocardiography. PMID:25108554

Papaioannou, Theodore G; Soulis, Dimitrios; Vardoulis, Orestis; Protogerou, Athanase; Sfikakis, Petros P; Stergiopulos, Nikolaos; Stefanadis, Christodoulos

2014-10-01

133

A USPL functional system with articulated mirror arm for in-vivo applications in dentistry  

NASA Astrophysics Data System (ADS)

Ultra-short pulsed laser (USPL) systems for dental application have overcome many of their initial disadvantages. However, a problem that has not yet been addressed and solved is the beam delivery into the oral cavity. The functional system that is introduced in this study includes an articulated mirror arm, a scanning system as well as a handpiece, allowing for freehand preparations with ultra-short laser pulses. As laser source an Nd:YVO4 laser is employed, emitting pulses with a duration of tp < 10 ps at a repetition rate of up to 500 kHz. The centre wavelength is at 1064 nm and the average output power can be tuned up to 9 W. The delivery system consists of an articulated mirror arm, to which a scanning system and a custom made handpiece are connected, including a 75 mm focussing lens. The whole functional system is compact in size and moveable. General characteristics like optical losses and ablation rate are determined and compared to results employing a fixed setup on an optical table. Furthermore classical treatment procedures like cavity preparation are being demonstrated on mammoth ivory. This study indicates that freehand preparation employing an USPL system is possible but challenging, and accompanied by a variety of side-effects. The ablation rate with fixed handpiece is about 10 mm3/min. Factors like defocussing and blinding affect treatment efficiency. Laser sources with higher average output powers might be needed in order to reach sufficient preparation speeds.

Schelle, Florian; Meister, Jörg; Dehn, Claudia; Oehme, Bernd; Bourauel, Christoph; Frentzen, Mathias

134

Diagnostic applications of gastric carcinoma cell aptamers in vitro and in vivo.  

PubMed

Gastric carcinoma is the most malignant tumor. Due to lacking of efficient means to diagnose the cancer at the early stage, it is necessary to develop effective molecular probes for early diagnosis and treatment. We have selected aptamers with high specificity and affinity against SGC7901 cells by cell-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) method, which shown important clinical applications: (1) Specific recognize human gastric tumor tissues compared to the normal tissues. (2)When used to capture cancerous cells, the aptamer-functionalized fluorescent-magnetic nanospheres (FMNS) could specifically capture 93% target cancer cells and about70% target cells can be released. (3) The aptamer probe displayed a quenched fluorescence in the absence of target cancer cells and went through a conformational transformation upon binding to target cancer cells that induced fluorescence. (4) The aptamer probe could target gastric tumors transplanted into mice with obvious fluorescence. The newly generated aptamers hold great potential in early cancer diagnosis. PMID:25618637

Ding, Fei; Guo, Shan; Xie, Min; Luo, Wei; Yuan, Chunhui; Huang, Weihua; Zhou, Yan; Zhang, Xiao-Lian; Zhou, Xiang

2015-03-01

135

Design and application of an in vivo reporter assay for phenylalanine ammonia-lyase.  

PubMed

Phenylalanine ammonia-lyase (PAL) is an important enzyme that links primary metabolism to secondary metabolism. Its efficiency is often a critical factor that affects the overall flux of a related metabolic pathway, the titer of the final products, and the efficacy of PAL-based therapies. Thus, PAL is a common target for metabolic engineering, and it is of significant interest to screen efficient PALs for industrial and medical applications. In this study, a novel and efficient visible reporter assay for screening of PAL efficiency in Escherichia coli was established based on a plant type III polyketide biosynthetic pathway. The candidate PALs were co-expressed with a 4-coumarate:CoA ligase 4CL1 from Arabidopsis thaliana and curcuminoid synthase (CUS) from Oryza sativa in E. coli BL21(DE3) to form a dicinnamoylmethane biosynthetic pathway. Taking advantage of the yellow color of the product, a microplate-based assay was designed to measure the titer of dicinnamoylmethane, which was validated by HPLC analysis. The different titers of the product reflect the overall performance (expression level and enzymatic activity) of the individual PALs in E. coli. Using this system, we have screened three PALs (PAL1, PAL3, and PAL4) from Trifolium pratense, among which PAL1 showed the best performance in E. coli. The engineered E. coli strain containing PAL1, 4CL1, and CUS led to the production of dicinnamoylmethane at a high level of 0.36 g/l. Supplement of 2-fluoro-phenylalanine yielded two fluorinated dicinnamoylmethane derivatives, 6,6'-difluoro-dicinnamoylmethane and 6-fluoro-dicinnamoylmethane, of which the latter is a new curcuminoid. PMID:23907258

Wang, Siyuan; Zhang, Shuwei; Zhou, Tong; Zeng, Jia; Zhan, Jixun

2013-09-01

136

Comparative in vitro and in vivo pharmacological investigation of platinum(IV) complexes as novel anticancer drug candidates for oral application.  

PubMed

Platinum(IV) complexes are promising candidates as prodrugs for oral application in anticancer chemotherapy. However, only a few Pt(IV) compounds entered (pre)clinical trials, e.g. satraplatin, while most of the others were only tested in vitro. Aim of the study was investigation of the in vivo pharmacological behavior as well as the anticancer activity of two novel platinum(IV) complexes vs. satraplatin. The drugs were selected due to significantly different in vitro cytotoxicity while sharing some physicochemical properties (e.g. lipophilicity). Initial experiments indicated that the highly in vitro cytotoxic compound 1 ((OC-6-33)-dichloridobis((4-ethoxy)-4-oxobutanoato)-bis(ethylamine)platinum(IV)) was also characterized by high drug absorption and tissue platinum levels after oral application. Interestingly, analysis of serum samples using SEC-ICP-MS revealed that the administered drugs have completely been metabolized and/or bound to proteins in serum within 2 h after treatment. With regard to the activity in vivo, the outcomes were rather unexpected: although potent anticancer effect of 1 was observed in cell culture, the effects in vivo were rather minor. Nevertheless, 1 was superior to 2 ((OC-6-33)-diammine(cyclobutane-1,1-dicarboxylato)-bis((4-cyclopentylamino)-4-oxobutanoato)platinum(IV)) after i.p. administration, which was, at least to some extent, in accordance to the cell culture experiments. After oral gavage, both compounds exhibited comparable activity. This is remarkable considering the distinctly lower activity of 2 in cell culture as well as the low platinum levels detected both in serum and tissues after oral application. Consequently, our data indicate that the prediction of in vivo anticancer activity by cell culture experiments is not trivial, especially for orally applied drugs. PMID:25413442

Theiner, Sarah; Varbanov, Hristo P; Galanski, Markus; Egger, Alexander E; Berger, Walter; Heffeter, Petra; Keppler, Bernhard K

2015-01-01

137

A volume birdcage coil with an adjustable sliding tuner ring for neuroimaging in high field vertical magnets: ex and in vivo applications at 21.1 T  

PubMed Central

A tunable 900 MHz transmit/receive volume coil was constructed for 1H MR imaging of biological samples in a 21.1 T vertical bore magnet. To accommodate a diverse range of specimen and RF loads at such a high frequency, a sliding-ring adaptation of a low-pass birdcage was implemented through simultaneous alteration of distributed capacitance. To make efficient use of the constrained space inside the vertical bore, a modular probe design was implemented with a bottom-adjustable tuning and matching apparatus. The sliding ring coil displays good homogeneity and sufficient tuning range for different samples of various dimensions representing large span of RF loads. High resolution in vivo and ex vivo images of large rats (up to 350 g), mice and human postmortem tissues were obtained to demonstrate coil functionality and to provide examples of potential applications at 21.1 T. PMID:22750638

Qian, Chunqi; Masad, Ihssan S.; Rosenberg, Jens T.; Elumalai, Malathy; Brey, William W.; Grant, Samuel C.; Gor’kov, Peter L.

2012-01-01

138

A volume birdcage coil with an adjustable sliding tuner ring for neuroimaging in high field vertical magnets: Ex and in vivo applications at 21.1 T  

NASA Astrophysics Data System (ADS)

A tunable 900 MHz transmit/receive volume coil was constructed for 1H MR imaging of biological samples in a 21.1 T vertical bore magnet. To accommodate a diverse range of specimen and RF loads at such a high frequency, a sliding-ring adaptation of a low-pass birdcage was implemented through simultaneous alteration of distributed capacitance. To make efficient use of the constrained space inside the vertical bore, a modular probe design was implemented with a bottom-adjustable tuning and matching apparatus. The sliding ring coil displays good homogeneity and sufficient tuning range for different samples of various dimensions representing large span of RF loads. High resolution in vivo and ex vivo images of large rats (up to 350 g), mice and human postmortem tissues were obtained to demonstrate coil functionality and to provide examples of potential applications at 21.1 T.

Qian, Chunqi; Masad, Ihssan S.; Rosenberg, Jens T.; Elumalai, Malathy; Brey, William W.; Grant, Samuel C.; Gor'kov, Peter L.

2012-08-01

139

Models and Applications of in Vivo Lung Morphometry with Hyperpolarized 3He MRI in a Mild COPD Population  

NASA Astrophysics Data System (ADS)

Hyperpolarized 3He diffusion MRI is increasingly used to non-invasively quantify local alveolar structure changes, such as those from Chronic Obstructive Pulmonary Disease (COPD). Previously, we described an in vivo lung morphometry technique that decouples the helium apparent diffusion coefficient (ADC) into components oriented along the longitudinal (DL) and transverse (DT) axes of the acinar airways. Herein, we discuss our recent expansion of this theory, which relates the anisotropy of the MRI diffusion signal to the geometrical parameters of the acinar airways. We demonstrate the utility of this model in human studies and compare the measured airway radii with prior ex vivo experiments.

Quirk, James D.; Sukstanskii, Alexander L.; Gierada, David S.; Woods, Jason C.; Conradi, Mark S.; Yablonskiy, Dmitriy A.

2008-12-01

140

Characteristics and Applications of the ToxRefDB In Vivo Datasets from Chronic, Reproductive and Developmental Assays  

EPA Science Inventory

ToxRefDB was developed to store data from in vivo animal toxicity studies. The initial focus was populating ToxRefDB with pesticide registration toxicity data that has been historically stored as hard-copy and scanned documents by the Office of Pesticide Programs. A significant p...

141

The application of statistical moment theory to the evaluation of in vivo dissolution time and absorption time  

Microsoft Academic Search

Moments analysis has been applied to the calculation of mean (in vivo)dissolution time (MDT) and mean absorption time (MAT) from plasma level of drug versus time data. Methods for accurately estimating the MDT under varying conditions, limitations of the methods, and interpretation of the data are presented. The importance of accurate estimates of the terminal rate constant (?z) and the

Sidney Riegelman; Paul Collier

1980-01-01

142

A parylene-based flexible electroporation chip applicable for in vivo gene and siRNA delivery  

Microsoft Academic Search

We report a parylene-based flexible electroporation chip for in vivo nucleic acid delivery. Benefited from the flexibility of parylene film, our chip fits the natural shape of the electroporated objects, thereby provides a uniform electric field over a large area. In addition, the subject is less likely to be harmed owing to the chip features, including good biocompatibility, less invasive

Zewen Wei; Yuanyu Huang; Deyao Zhao; Zicai Liang; Zhihong Li

2011-01-01

143

Rapid response oxygen-sensing nanofibers  

PubMed Central

Molecular oxygen has profound effects on cell and tissue viability. Relevant sensor forms that can rapidly determine dissolved oxygen levels under biologically relevant conditions provide critical metabolic information. Using 0.5 ?m diameter electrospun polycaprolactone (PCL) fiber containing an oxygen-sensitive probe, tris (4,7-diphenyl-1,10-phenanthroline) ruthenium(II) dichloride, we observed a response time of 0.9±0.12 seconds – 4–10 times faster than previous reports – while the t95 for the corresponding film was more than two orders of magnitude greater. Interestingly, the response and recovery times of slightly larger diameter PCL fibers were 1.79±0.23 s and 2.29±0.13 s, respectively, while the recovery time was not statistically different likely due to the more limited interactions of nitrogen with the polymer matrix. A more than 10-fold increase in PCL fiber diameter reduces oxygen sensitivity while having minor effects on response time; conversely, decreases in fiber diameter to less than 0.5 ?m would likely decrease response times even further. In addition, a 50°C heat treatment of the electrospun fiber resulted in both increased Stern-Volmer slope and linearity likely due to secondary recrystallization that further homogenized the probe microenvironment. At exposure times up to 3600 s in length, photobleaching was observed but was largely eliminated by the use of either polyethersulfone (PES) or a PES-PCL core-shell composition. However, this resulted in 2- and 3-fold slower response times. Finally, even the non-core shell compositions containing the Ru oxygen probe result in no apparent cytotoxicity in representative glioblastoma cell populations. PMID:23706233

Xue, Ruipeng; Behera, Prajna; Viapiano, Mariano S.; Lannutti, John J.

2014-01-01

144

?TCP ceramic doped with dicalcium silicate for bone regeneration applications prepared by powder metallurgy method: in vitro and in vivo studies.  

PubMed

This study reports on the in vitro and in vivo behavior of ?-tricalcium phosphate (?TCP) and also ?TCP doped with either 1.5 or 3.0 wt % of dicalcium silicate (C2 S). The ceramics were successfully prepared by powder metallurgy method combined with homogenization and heat treatment procedures. All materials were composed of a single-phase, ?TCP in the case of a pure material, or solid solution of C2 S in ?TCP for the doped ?TCP, which were stable at room temperature. The ceramics were tested for bioactivity in simulated body fluid, cell culture medium containing adult mesenchymal stem cells of human origin, and in animals. Analytical scanning electron microscopy combined with chemical elemental analysis was used and Fourier transform infrared and conventional histology methods. The in vivo behavior of the ceramics matched the in vitro results, independently of the C2 S content in ?TCP. Carbonated hydroxyapatite (CHA) layer was formed on the surface and within the inner parts of the specimens in all cases. A fully mineralized new bone growing in direct contact with the implants was found under the in vivo conditions. The bioactivity and biocompatibility of the implants increased with the C2 S content in ?TCP. The C2 S doped ceramics also favoured a phase transformation of ?TCP into CHA, important for full implant integration during the natural bone healing processes. ?TCP ceramic doped with 3.0 wt % C2 S showed the best bioactive in vitro and in vivo properties of all the compositions and hence could be of interest in specific applications for bone restorative purposes. PMID:23225787

Velasquez, Pablo; Luklinska, Zofia B; Meseguer-Olmo, Luis; Mate-Sanchez de Val, Jose E; Delgado-Ruiz, Rafael A; Calvo-Guirado, Jose L; Ramirez-Fernandez, Ma P; de Aza, Piedad N

2013-07-01

145

AO-OCT for in vivo mouse retinal imaging: Application of adaptive lens in wavefornt sensorless aberration correction  

NASA Astrophysics Data System (ADS)

We demonstrate Adaptive optics - Optical Coherence Tomography (OCT) with modal sensorless Adaptive Optics correction with the use of novel Adaptive Lens (AL) applied for in-vivo imaging of mouse retinas. The AL can generate low order aberrations: defocus, astigmatism, coma and spherical aberration that were used in an adaptive search algorithm. Accelerated processing of the OCT data with a Graphic Processing Unit (GPU) permitted real time extraction of image projection total intensity for arbitrarily selected retinal depth plane to be optimized. Wavefront sensorless control is a viable option for imaging biological structures for which AOOCT cannot establish a reliable wavefront that could be corrected by wavefront corrector. Image quality improvements offered by adaptive lens with sensorless AO-OCT was evaluated on in vitro samples followed by mouse retina data acquired in vivo.

Bonora, Stefano; Jian, Yifan; Pugh, Edward N.; Sarunic, Marinko V.; Zawadzki, Robert J.

2014-03-01

146

Generation of novel reporter stem cells and their application for molecular imaging of cardiac-differentiated stem cells in vivo.  

PubMed

Stem cell therapies offer the potential for repair and regeneration of cardiac tissue. To facilitate evaluation of stem cell activity in vivo, we created novel dual-reporter mouse embryonic stem (mES) cell lines that express the firefly luciferase (LUC) reporter gene under the control of the cardiac sodium-calcium exchanger-1 (Ncx-1) promoter in the background of the 7AC5-EYFP mES cell line that constitutively expresses the enhanced yellow fluorescent protein (EYFP). We compared the ability of recombinant clonal cell lines to express LUC before and after induction of cardiac differentiation in vitro. In particular, one of the clonal cell lines (Ncx-1-43LUC mES cells) showed markedly enhanced LUC expression (45-fold increase) upon induction of cardiac differentiation in vitro. Further, cardiac differentiation in these cells was perpetuated over a period of 2-4 weeks after transplantation in a neonatal mouse heart model, as monitored by noninvasive bioluminescence imaging (BLI) and confirmed via postmortem immunofluorescence and histological assessments. In contrast, transplantation of undifferentiated pluripotent Ncx-1-43LUC mES cells in neonatal hearts did not result in detectable levels of cardiac differentiation in these cells in vivo. These results suggest that prior induction of cardiac differentiation in vitro enhances development and maintenance of a cardiomyocyte-like phenotype for mES cells following transplantation into neonatal mouse hearts in vivo. We conclude that the Ncx-1-43LUC mES cell line is a novel tool for monitoring early cardiac differentiation in vivo using noninvasive BLI. PMID:20109065

Kammili, Ramana K; Taylor, David G; Xia, Jixiang; Osuala, Kingsley; Thompson, Kellie; Menick, Donald R; Ebert, Steven N

2010-09-01

147

In-Vivo Measurement of Dynamic Joint Motion Using High Speed Biplane Radiography and CT: Application to Canine ACL Deficiency  

Microsoft Academic Search

standing normal joint function as well as the effects of injury or disease. This paper presents a novel technique for measuring in-vivo skeletal kinematics that combines data collected from high-speed biplane radiography and static computed tomography (CT). The goals of the present study were to demonstrate that highly precise measurements can be obtained during dynamic movement studies employing high frame-rate

Scott Tashman; William Anderst

2003-01-01

148

Application of Twyman-Green interferometer for evaluation of in vivo breakup characteristic of the human tear film  

NASA Astrophysics Data System (ADS)

The paper presents an interferometric method of assessing the in vivo stability of the precorneal tear film. To observe dynamic effects on a human cornea the Twyman-Green interferometer with television frame speed digital registration synchronized with a laser flash was used. The instrument was applied to the human cornea in vivo. The results of the experiment, both tear film distribution and its dynamics, are presented. The proposed interferometric setup can be used to evaluate the breakup characteristics of the tear film, its distribution, and to examine its dynamic changes. The breakup profiles and their cross sections calculated from the interferogram analysis are presented. The depth of recorded breakup, calculated on the basis of interferogram analysis, amounts to about 1.5 micrometers . The proposed method has the advantage of being noncontact and applies only a low-energy laser beam to the eye. This provides noninvasive viewing of human cornea in vivo and makes it possible to observe the kinetics of its tear film deterioration.

Licznerski, Tomasz J.; Kasprzak, Henryk T.; Kowalik, Waldemar

1999-01-01

149

Application of Ultrasound on Monitoring the Evolution of the Collagen Fiber Reinforced nHAC/CS Composites In Vivo  

PubMed Central

To date, fiber reinforce scaffolds have been largely applied to repair hard and soft tissues. Meanwhile, monitoring the scaffolds for long periods in vivo is recognized as a crucial issue before its wide use. As a consequence, there is a growing need for noninvasive and convenient methods to analyze the implantation remolding process in situ and in real time. In this paper, diagnostic medical ultrasound was used to monitor the in vivo bone formation and degradation process of the novel mineralized collagen fiber reinforced composite which is synthesized by chitosan (CS), nanohydroxyapatite (nHA), and collagen fiber (Col). To observe the impact of cells on bone remodeling process, the scaffolds were planted into the back of the SD rats with and without rat bone mesenchymal stem cells (rBMSCs). Systematic data of scaffolds in vivo was extracted from ultrasound images. Significant consistency between the data from the ultrasound and DXA could be observed (P < 0.05). This indicated that ultrasound may serve as a feasible alternative for noninvasive monitoring the evolution of scaffolds in situ during cell growth. PMID:24822206

Chen, Yan; Yan, Yuting; Li, Xiaoming; Tan, Huiting; Li, Huajun; Zhu, Yanwen; Niemeyer, Philipp; Yaega, Matin; Yu, Bo

2014-01-01

150

Aptamer photoregulation in vivo.  

PubMed

The in vivo application of aptamers as therapeutics could be improved by enhancing target-specific accumulation while minimizing off-target uptake. We designed a light-triggered system that permits spatiotemporal regulation of aptamer activity in vitro and in vivo. Cell binding by the aptamer was prevented by hybridizing the aptamer to a photo-labile complementary oligonucleotide. Upon irradiation at the tumor site, the aptamer was liberated, leading to prolonged intratumoral retention. The relative distribution of the aptamer to the liver and kidney was also significantly decreased, compared to that of the free aptamer. PMID:25404344

Li, Lele; Tong, Rong; Chu, Hunghao; Wang, Weiping; Langer, Robert; Kohane, Daniel S

2014-12-01

151

Feasibility Study of Glass Dosimeter for In Vivo Measurement: Dosimetric Characterization and Clinical Application in Proton Beams  

SciTech Connect

Purpose: To evaluate the suitability of the GD-301 glass dosimeter for in vivo dose verification in proton therapy. Methods and Materials: The glass dosimeter was analyzed for its dosimetrics characteristic in proton beam. Dosimeters were calibrated in a water phantom using a stairlike holder specially designed for this study. To determine the accuracy of the glass dosimeter in proton dose measurements, we compared the glass dosimeter and thermoluminescent dosimeter (TLD) dose measurements using a cylindrical phantom. We investigated the feasibility of the glass dosimeter for the measurement of dose distributions near the superficial region for proton therapy plans with a varying separation between the target volume and the surface of 6 patients. Results and Discussion: Uniformity was within 1.5%. The dose-response has good linearity. Dose-rate, fading, and energy dependence were found to be within 3%. The beam profile measured using the glass dosimeter was in good agreement with the profile obtained from the ionization chamber. Depth-dose distributions in nonmodulated and modulated proton beams obtained with the glass dosimeter were estimated to be within 3%, which was lower than those with the ionization chamber. In the phantom study, the difference of isocenter dose between the delivery dose calculated by the treatment planning system and that measured by the glass dosimeter was within 5%. With in vivo dosimetry, the calculated surface doses overestimated measurements by 4%-16% using glass dosimeter and TLD. Conclusion: It is recommended that bolus be added for these clinical cases. We also believe that the glass dosimeter has considerable potential for use with in vivo patient proton dosimetry.

Rah, Jeong-Eun; Oh, Do Hoon; Kim, Jong Won [Department of Radiation Oncology, Myongji Hospital, Kwandong University College of Medicine, Goyang (Korea, Republic of)] [Department of Radiation Oncology, Myongji Hospital, Kwandong University College of Medicine, Goyang (Korea, Republic of); Kim, Dae-Hyun; Suh, Tae-Suk [Department of Biomedical Engineering, Catholic University of Korea, Seoul (Korea, Republic of)] [Department of Biomedical Engineering, Catholic University of Korea, Seoul (Korea, Republic of); Ji, Young Hoon [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)] [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Shin, Dongho; Lee, Se Byeong; Kim, Dae Yong [Proton Therapy Center, National Cancer Center, Goyang (Korea, Republic of)] [Proton Therapy Center, National Cancer Center, Goyang (Korea, Republic of); Park, Sung Yong, E-mail: Sung.Park@mclaren.org [Proton Therapy Center, McLaren Cancer Institute, Flint, Michigan (United States)

2012-10-01

152

Near-infrared emission Ba3(PO4)2:Mn5+ phosphor and potential application in vivo fluorescence imaging.  

PubMed

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1350 nm) is attracting attention due to negligible tissue scattering and lower tissue autofluorescence, etc. Here, Ba3(PO4)2:Mn(5+) phosphor is prepared via solid state reaction method in air, and NIR emission band peaking at ?1191 nm in the NIR-II region is observed. According to experiment results, Ba3(PO4)2:Mn(5+) phosphor has a great potential for the study of the NIR-II fluorescence imaging in vivo. PMID:24691378

Cao, Renping; Yu, Xiaoguang; Sun, Xinyuan; Cao, Chunyan; Qiu, Jianrong

2014-07-15

153

Observation of Multiphoton-induced Fluorescence from Nano Graphene Oxide and Its Applications in In vitro and In vivo Bioimaging  

E-print Network

In the present paper, we observed both two-photon and three-photon induced distinct photoluminescence from GO nanoparticles under fs laser excitation. Conjugated with PEG molecules, GO nanoparticles exhibited high chemical stability, and could effectively label HeLa cells. Imaged with a two-photon scanning microscope, GO nanoparticles were observed to localize in the mitochondria, endoplasmic reticulum, Golgi and lysosome of HeLa cells. Furthermore, GO nanoparticles were micro-injected into the brain of a black mouse, and in vivo two-photon luminescence imaging illustrated that GO nanoparticles located at 300 {\\mu}m depth in the brain could be clearly distinguished.

Qian, Jun; Peng, Li; Xi, Wang; Cai, Fu-Hong; Zhu, Zhen-Feng; He, Hao; Hu, Ming-Lie; He, Sailing

2012-01-01

154

Application of wide-field optical coherence tomography to monitoring of viability of rat brain in vivo  

NASA Astrophysics Data System (ADS)

We investigated the feasibility of OCT in monitoring the viability of the brain. It was confirmed that after an overdose of pentobarbital sodium salt for an euthanasia, the OCT signal intensity increased before cardiac arrest and finally became 2.7 times, and by periodically changing the tissue temperature from 20 to 32 °C in vivo, average correlation coefficients between the ratio of signal intensity (RSI) and temperature were determined to be -0:42 to -0:50. RSI reversibly changed with subsequent variations of temperatures and finally increased rapidly just before cardiac arrest. These results indicate that RSI could correspond to decreases in viability.

Sato, Manabu; Nishidate, Izumi

2014-05-01

155

Application of the critical angle method to refractive index measurement of human skin in vivo under partial contact  

NASA Astrophysics Data System (ADS)

We adapted the critical angle method for measuring rough surfaces under partial contact to acquire an in vivo skin refractive index (RI). Assuming that the total reflection is the simple sum of reflection from areas that are in contact and reflection from those that are not in contact, the RI can be estimated even for partial contact with a rough surface. We found that cheek skin is sufficiently soft that a sufficiently large area can be in contact and that the critical angle was detectable. The RIs of the cheeks of adult females were measured. The RI range was about 1.51 to 1.53, at a wavelength of 550 nm, without considering systematic errors. The RIs of cheeks are significantly correlated with their conductance, which corresponds to their water content. We determined the relationship between the RI and conductance within the variation of skin under normal conditions; this relationship was theoretically obtained in previous studies. In the present study, a direct in vivo measurement method was developed that enabled us to measure the RI in daily life, although this method contains errors for several reasons, including disregarding absorption.

Yoshida, Kenichiro; Ohkubo, Kohji; Ojima, Nobutoshi; Iwata, Kayoko

2013-03-01

156

Application of the critical angle method to refractive index measurement of human skin in vivo under partial contact.  

PubMed

We adapted the critical angle method for measuring rough surfaces under partial contact to acquire an in vivo skin refractive index (RI). Assuming that the total reflection is the simple sum of reflection from areas that are in contact and reflection from those that are not in contact, the RI can be estimated even for partial contact with a rough surface. We found that cheek skin is sufficiently soft that a sufficiently large area can be in contact and that the critical angle was detectable. The RIs of the cheeks of adult females were measured. The RI range was about 1.51 to 1.53, at a wavelength of 550 nm, without considering systematic errors. The RIs of cheeks are significantly correlated with their conductance, which corresponds to their water content. We determined the relationship between the RI and conductance within the variation of skin under normal conditions; this relationship was theoretically obtained in previous studies. In the present study, a direct in vivo measurement method was developed that enabled us to measure the RI in daily life, although this method contains errors for several reasons, including disregarding absorption. PMID:23455964

Yoshida, Kenichiro; Ohkubo, Kohji; Ojima, Nobutoshi; Iwata, Kayoko

2013-03-01

157

In vivo application of an optical segment tracking approach for bone loading regimes recording in humans: a reliability study.  

PubMed

This paper demonstrates an optical segment tracking (OST) approach for assessing the in vivo bone loading regimes in humans. The relative movement between retro-reflective marker clusters affixed to the tibia cortex by bone screws was tracked and expressed as tibia loading regimes in terms of segment deformation. Stable in vivo fixation of bone screws was tested by assessing the resonance frequency of the screw-marker structure and the relative marker position changes after hopping and jumping. Tibia deformation was recorded during squatting exercises to demonstrate the reliability of the OST approach. Results indicated that the resonance frequencies remain unchanged prior to and after all exercises. The changes of Cardan angle between marker clusters induced by the exercises were rather minor, maximally 0.06°. The reproducibility of the deformation angles during squatting remained small (0.04°/m-0.65°/m). Most importantly, all surgical and testing procedures were well tolerated. The OST method promises to bring more insights of the mechanical loading acting on bone than in the past. PMID:24907129

Yang, Peng-Fei; Sanno, Maximilian; Ganse, Bergita; Koy, Timmo; Brüggemann, Gert-Peter; Müller, Lars Peter; Rittweger, Jörn

2014-08-01

158

Comparison of elastic scattering spectroscopy with histology in ex vivo prostate glands: potential application for optically guided biopsy and directed treatment.  

PubMed

The false-negative rate of ultrasound-guided sextant prostate biopsy has been estimated to be as high as 35 %. A significant percentage (10-35 %) of these prostate cancers diagnosed at a second or later attempt are high grade and, therefore, potentially lethal. We discuss the feasibility for performing optically guided biopsy using elastic scattering spectroscopy (ESS) to reduce sampling errors and improve sensitivity. ESS measurements were performed on 42 prostate glands ex vivo and correlated with standard histopathological assessment. Sliced glands were examined with wavelength ranges of 330-760 nm. The ESS portable system used a new fiber-optic probe with integrated cutting tool, designed specifically for ex vivo pathology applications. ESS spectra were grouped by diagnosis from standard histopathological procedure and then classified using linear support vector machine. Preliminary data are encouraging. ESS data showed strong spectral trends correlating with the histopathological assignments. The classification results showed a sensitivity of 0.83 and specificity of 0.87 for distinguishing dysplastic prostatic tissue from benign prostatic tissue. Similar results were obtained for distinguishing dysplastic prostatic tissue from prostatitis with a sensitivity and specificity of 0.80 and 0.88, respectively. The negative predictive values obtained with ESS are better than those obtained with transrectal ultrasound (TRUS)-guided core-needle biopsy. PMID:23247663

A'Amar, O M; Liou, L; Rodriguez-Diaz, E; De las Morenas, A; Bigio, I J

2013-09-01

159

Successful application of ex vivo expanded human autologous oral mucosal epithelium for the treatment of total bilateral limbal stem cell deficiency.  

PubMed

Ocular surface reconstruction with ex vivo expanded limbal stem cells (LSCs) is a widely used clinical treatment for patients with limbal stem cell deficiency (LSCD). This is not applicable to patients with bilateral LSCD where there are no remaining LSCs. Cultivated oral mucosa epithelium (OME) has been used as an alternative source of autologous epithelial stem cells for ocular reconstruction in few clinical trials. However, successful generation of stratified OME epithelium has only been achieved in the presence of animal feeder cells and/or animal-derived products in the culture media, likely to contribute to increased risk of pathogen transmission and graft rejection. In this study, we report generation of multilayered OME epithelium that shares many of the characteristics of corneal epithelium using a fully compliant good manufacturing practice, feeder- and animal product-free method. Proof of concept was achieved by transplantation of autologous ex vivo expanded OME in two patients with histologically confirmed bilateral total LSCD that resulted in successful reversal of LSCD in the treated eye up to 24 months. PMID:24590515

Kolli, Sai; Ahmad, Sajjad; Mudhar, Hardeep Singh; Meeny, Adam; Lako, Majlinda; Figueiredo, Francisco C

2014-08-01

160

In vivo application of ( sup 111 In-DTPA-D-Phe sup 1 )-octreotide for detection of somatostatin receptor-positive tumors in rats  

SciTech Connect

In this study the authors investigated its in vivo application in the visualization of somatostatin receptor-positive tumors in rats. The distribution of the radiopharmaceutical was investigated after intravenous injection in normal rats and in rats bearing the somatostatin receptor-positive rat pancreatic carcinoma CA 20948. Ex vivo autoradiographic studies showed that specific accumulation of radioactivity occurred in somatostatin receptor-containing tissue (anterior pituitary gland). However, in contrast to the adrenals and pituitary, the tracer accumulation in the kidneys was not mediated by somatostatin receptors. Increasing radioactivity over the somatostatin receptor-positive tumors was measured rapidly after injection and the tumors were clearly visualized by gamma camera scintigraphy. In rats pretreated with 1 mg octreotide accumulation of ({sup 111}In-DPTA-D-Phe{sup 1})-octreotide in the tumors was prevented. Because of its relatively long effective half-life, ({sup 111}In-DTPA-D-Phe{sup 1})-octreotide is a radionuclide-coupled somatostatin analogue which can be used to visualize somatostatin receptor-bearing tumors efficiently after 24 hr, when interfering background radioactivity is minimized by renal clearance.

Bakker, W.H.; Krenning, E.P.; Reubi, J.C.; Breeman, W.A.P.; Setyono-Han, B.; de Jong, M.; Kooij, P.P.M.; Bruns, C.; van Hagen, P.M.; Marbach, P.; Visser, T.J.; Pless, J.; Lamberts, S.W.J. (Erasmus Univ., Rotterdam (Netherlands) Sandoz Research Inst., Berne (Switzerland) Dr. Daniel den Hoed Cancer Centre, Rotterdam (Netherlands) Sandoz Pharma AG, Basel (Switzerland))

1991-01-01

161

Application of a physiologically based pharmacokinetic model to assess propofol hepatic and renal glucuronidation in isolation: utility of in vitro and in vivo data.  

PubMed

A physiologically based pharmacokinetic (PBPK) modeling approach was used to assess the prediction accuracy of propofol hepatic and extrahepatic metabolic clearance and to address previously reported underprediction of in vivo clearance based on static in vitro-in vivo extrapolation methods. The predictive capacity of propofol intrinsic clearance data (CLint) obtained in human hepatocytes and liver and kidney microsomes was assessed using the PBPK model developed in MATLAB software. Microsomal data obtained by both substrate depletion and metabolite formation methods and in the presence of 2% bovine serum albumin were considered in the analysis. Incorporation of hepatic and renal in vitro metabolic clearance in the PBPK model resulted in underprediction of propofol clearance regardless of the source of in vitro data; the predicted value did not exceed 35% of the observed clearance. Subsequently, propofol clinical data from three dose levels in intact patients and anhepatic subjects were used for the optimization of hepatic and renal CLint in a simultaneous fitting routine. Optimization process highlighted that renal glucuronidation clearance was underpredicted to a greater extent than liver clearance, requiring empirical scaling factors of 17 and 9, respectively. The use of optimized clearance parameters predicted hepatic and renal extraction ratios within 20% of the observed values, reported in an additional independent clinical study. This study highlights the complexity involved in assessing the contribution of extrahepatic clearance mechanisms and illustrates the application of PBPK modeling, in conjunction with clinical data, to assess prediction of clearance from in vitro data for each tissue individually. PMID:23303442

Gill, Katherine L; Gertz, Michael; Houston, J Brian; Galetin, Aleksandra

2013-04-01

162

Potential application of in vivo imaging of impaired lymphatic duct to evaluate the severity of pressure ulcer in mouse model  

NASA Astrophysics Data System (ADS)

Ischemia-reperfusion (IR) injury is a cause of pressure ulcer. However, a mechanism underlying the IR injury-induced lymphatic vessel damage remains unclear. We investigated the alterations of structure and function of lymphatic ducts in a mouse cutaneous IR model. And we suggested a new method for evaluating the severity of pressure ulcer. Immunohistochemistry showed that lymphatic ducts were totally vanished by IR injury, while blood vessels were relatively preserved. The production of harmful reactive oxygen species (ROS) was increased in injured tissue. In vitro study showed a high vulnerability of lymphatic endothelial cells to ROS. Then we evaluated the impaired lymphatic drainage using an in vivo imaging system for intradermally injected indocyanine green (ICG). The dysfunction of ICG drainage positively correlated with the severity of subsequent cutaneous changes. Quantification of the lymphatic duct dysfunction by this imaging system could be a useful strategy to estimate the severity of pressure ulcer.

Kasuya, Akira; Sakabe, Jun-Ichi; Tokura, Yoshiki

2014-02-01

163

Potential application of in vivo imaging of impaired lymphatic duct to evaluate the severity of pressure ulcer in mouse model  

PubMed Central

Ischemia-reperfusion (IR) injury is a cause of pressure ulcer. However, a mechanism underlying the IR injury-induced lymphatic vessel damage remains unclear. We investigated the alterations of structure and function of lymphatic ducts in a mouse cutaneous IR model. And we suggested a new method for evaluating the severity of pressure ulcer. Immunohistochemistry showed that lymphatic ducts were totally vanished by IR injury, while blood vessels were relatively preserved. The production of harmful reactive oxygen species (ROS) was increased in injured tissue. In vitro study showed a high vulnerability of lymphatic endothelial cells to ROS. Then we evaluated the impaired lymphatic drainage using an in vivo imaging system for intradermally injected indocyanine green (ICG). The dysfunction of ICG drainage positively correlated with the severity of subsequent cutaneous changes. Quantification of the lymphatic duct dysfunction by this imaging system could be a useful strategy to estimate the severity of pressure ulcer. PMID:24566895

Kasuya, Akira; Sakabe, Jun-ichi; Tokura, Yoshiki

2014-01-01

164

Application of LC-MS/MS method for the in vivo metabolite determination of oleuropein after intravenous administration to rat.  

PubMed

A highly sensitive, specific and simple LC-MS/MS method was developed to investigate in vivo bio-transformation of oleuropein in rat. Rat urine samples collected after the intravenous administrations were determined using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the negative-ion mode. The assay procedure involves a simple liquid-liquid extraction of parent oleuropein and the metabolite from rat urine with ethyl acetate. Chromatographic separation was operated with 0.1% formic acid aqueous and methanol in gradient program at a flow rate of 0.80?mL/min on an RP-C(18) column with a total run time of 30?min. This method has been successfully applied to simultaneous determination of oleuropein and its metabolite in rat urine. Oxygenation was found to be the major metabolic pathway of the oleuropein in rat after intravenous administration. PMID:21308708

Zhou, Ting; Qian, Tianxiu; Wang, Xiaoying; Li, Xianen; Cao, Li; Gui, Shuangying

2011-12-01

165

Non-contact respiration monitoring for in-vivo murine micro computed tomography: characterization and imaging applications  

PubMed Central

A cone beam micro-CT has previously been utilized along with a pressure-tracking respiration sensor to acquire prospectively gated images of both wild-type mice and various adult murine disease models. While the pressure applied to the abdomen of the subject by this sensor is small and is generally without physiological effect, certain disease models of interest, as well as very young animals, are prone to atelectasis with added pressure, or they generate too weak of a respiration signal with this method to achieve optimal prospective gating. In this work we present a new fiber-optic displacement sensor which monitors respiratory motion of a subject without requiring physical contact. The sensor outputs an analog signal which can be used for prospective respiration gating in micro-CT imaging. The device was characterized and compared against a pneumatic air chamber pressure sensor for the imaging of adult wild-type mice. The resulting images were found to be of similar quality with respect to physiological motion blur; the quality of the respiration signal trace obtained using the non-contact sensor was comparable to that of the pressure sensor and was superior for gating purposes due to its better signal-to-noise ratio. The non-contact sensor was then used to acquire in-vivo micro-CT images of a murine model for congenital diaphragmatic hernia and of 11-day-old mouse pups. In both cases, quality CT images were successfully acquired using this new respiration sensor. Despite the presence of beam hardening artifact arising from the presence of a fiber-optic cable in the imaging field, we believe this new technique for respiration monitoring and gating presents an opportunity for in-vivo imaging of disease models which were previously considered too delicate for established animal handling methods. PMID:22948192

Burk, Laurel M; Lee, Yueh Z; Wait, J Matthew; Lu, Jianping; Zhou, Otto Z

2012-01-01

166

Non-contact respiration monitoring for in-vivo murine micro computed tomography: characterization and imaging applications  

NASA Astrophysics Data System (ADS)

A cone beam micro-CT has previously been utilized along with a pressure-tracking respiration sensor to acquire prospectively gated images of both wild-type mice and various adult murine disease models. While the pressure applied to the abdomen of the subject by this sensor is small and is generally without physiological effect, certain disease models of interest, as well as very young animals, are prone to atelectasis with added pressure, or they generate too weak a respiration signal with this method to achieve optimal prospective gating. In this work we present a new fibre-optic displacement sensor which monitors respiratory motion of a subject without requiring physical contact. The sensor outputs an analogue signal which can be used for prospective respiration gating in micro-CT imaging. The device was characterized and compared against a pneumatic air chamber pressure sensor for the imaging of adult wild-type mice. The resulting images were found to be of similar quality with respect to physiological motion blur; the quality of the respiration signal trace obtained using the non-contact sensor was comparable to that of the pressure sensor and was superior for gating purposes due to its better signal-to-noise ratio. The non-contact sensor was then used to acquire in-vivo micro-CT images of a murine model for congenital diaphragmatic hernia and of 11-day-old mouse pups. In both cases, quality CT images were successfully acquired using this new respiration sensor. Despite the presence of beam hardening artefacts arising from the presence of a fibre-optic cable in the imaging field, we believe this new technique for respiration monitoring and gating presents an opportunity for in-vivo imaging of disease models which were previously considered too delicate for established animal handling methods.

Burk, Laurel M.; Lee, Yueh Z.; Wait, J. Matthew; Lu, Jianping; Zhou, Otto Z.

2012-09-01

167

In vivo induction of aryl hydrocarbon hydroxylase in human scalp hair follicles by topical application of a commercial coal tar preparation.  

PubMed

Five low-dose applications of a commercial coal tar preparation on a small scalp skin region resulted in an induction of aryl hydrocarbon hydroxylase (AHH) activity in freshly isolated human hair follicles. Large but reproducible interindividual differences in AHH-inducibility could be detected. The method offers the opportunity to measure AHH-inducibility, which has been correlated to the risk of developing chemical-induced cancer, in vivo in normal epithelium, a cell-type highly relevant for chemical carcinogenesis. Smoking habits did not have any effect on AHH-activity in freshly isolated hair follicles. Therefore the method potentially permits the identification of persons with high and low genetically determined AHH-inducibility. PMID:6378361

Hukkelhoven, M W; Vromans, L W; van Pelt, F N; Keulers, R A; Vermorken, A J

1984-06-01

168

Application of the holographic interference microscope for investigation of ozone therapy influence on blood erythrocytes of patients in vivo  

Microsoft Academic Search

This paper is devoted to application medical ozone influence on morphology of blood erythrocytes of patients with neurosensor hardness of hearing using holographic interference microscope. From the experimental results, it was found that erythrocytes of all patients before treatment had \\

T. V. Tishko; V. P. Titar; T. M. Barchotkina; D. N. Tishko

2003-01-01

169

Folic acid-functionalized up-conversion nanoparticles: toxicity studies in vivo and in vitro and targeted imaging applications  

NASA Astrophysics Data System (ADS)

Folate receptors (FRs) are overexpressed on a variety of human cancer cells and tissues, including cancers of the breast, ovaries, endometrium, and brain. This over-expression of FRs can be used to target folate-linked imaging specifically to FR-expressing tumors. Fluorescence is emerging as a powerful new modality for molecular imaging in both the diagnosis and treatment of disease. Combining innovative molecular biology and chemistry, we prepared three kinds of folate-targeted up-conversion nanoparticles as imaging agents (UCNC-FA: UCNC-Er-FA, UCNC-Tm-FA, and UCNC-Er,Tm-FA). In vivo and in vitro toxicity studies showed that these nanoparticles have both good biocompatibility and low toxicity. Moreover, the up-conversion luminescence imaging indicated that they have good targeting to HeLa cells and can therefore serve as potential fluorescent contrast agents.Folate receptors (FRs) are overexpressed on a variety of human cancer cells and tissues, including cancers of the breast, ovaries, endometrium, and brain. This over-expression of FRs can be used to target folate-linked imaging specifically to FR-expressing tumors. Fluorescence is emerging as a powerful new modality for molecular imaging in both the diagnosis and treatment of disease. Combining innovative molecular biology and chemistry, we prepared three kinds of folate-targeted up-conversion nanoparticles as imaging agents (UCNC-FA: UCNC-Er-FA, UCNC-Tm-FA, and UCNC-Er,Tm-FA). In vivo and in vitro toxicity studies showed that these nanoparticles have both good biocompatibility and low toxicity. Moreover, the up-conversion luminescence imaging indicated that they have good targeting to HeLa cells and can therefore serve as potential fluorescent contrast agents. Electronic supplementary information (ESI) available: Up-conversion luminescence spectra of UCNC-Er and UCNC-Er-FA, UCNC-Tm and UCNC-Tm-FA. Confocal luminescence imaging data collected as a series along the Z optical axis. See DOI: 10.1039/c4nr02312a

Sun, Lining; Wei, Zuwu; Chen, Haige; Liu, Jinliang; Guo, Jianjian; Cao, Ming; Wen, Tieqiao; Shi, Liyi

2014-07-01

170

Automated Segmentation and Object Classification of CT Images: Application to In Vivo Molecular Imaging of Avian Embryos.  

PubMed

Background. Although chick embryogenesis has been studied extensively, there has been growing interest in the investigation of skeletogenesis. In addition to improved poultry health and minimized economic loss, a greater understanding of skeletal abnormalities can also have implications for human medicine. True in vivo studies require noninvasive imaging techniques such as high-resolution microCT. However, the manual analysis of acquired images is both time consuming and subjective. Methods. We have developed a system for automated image segmentation that entails object-based image analysis followed by the classification of the extracted image objects. For image segmentation, a rule set was developed using Definiens image analysis software. The classification engine was implemented using the WEKA machine learning tool. Results. Our system reduces analysis time and observer bias while maintaining high accuracy. Applying the system to the quantification of long bone growth has allowed us to present the first true in ovo data for bone length growth recorded in the same chick embryos. Conclusions. The procedures developed represent an innovative approach for the automated segmentation, classification, quantification, and visualization of microCT images. MicroCT offers the possibility of performing longitudinal studies and thereby provides unique insights into the morpho- and embryogenesis of live chick embryos. PMID:23997760

Heidrich, Alexander; Schmidt, Jana; Zimmermann, Johannes; Saluz, Hans Peter

2013-01-01

171

Preparation and In Vitro/Ex Vivo Evaluation of Moxifloxacin-Loaded PLGA Nanosuspensions for Ophthalmic Application  

PubMed Central

The aim of the present investigation was to prepare a colloidal ophthalmic formulation to improve the residence time of moxifloxacin. Moxifloxacin-loaded poly(dl-lactide-co-glycolide) (PLGA) nanosuspensions were prepared by using the solvent evaporation technique. The nanosuspensions were characterised physically by using different techniques like particle size, zeta potential, FTIR, DSC, and XRD analysis. In vitro and ex vivo studies of nanosuspensions were carried out using a modified USP dissolution apparatus and all-glass Franz diffusion cells, respectively. The antibacterial activities of the nanosuspension and marketed formulations were performed against S. aureus and P. aeroginosa. The moxifloxacin-loaded PLGA nanosuspensions showed uniform particle size, ranging between 164–490 nm with negative zeta potential for all batches. The percentage entrapment efficiency of the drug-loaded nano-suspension was found to be between 84.09 to 92.05%. In vitro drug release studies suggest that all of the formulations showed extended drug release profiles and follow Korsemeyer-Peppas release kinetics. In vitro corneal permeability was found to be comparable with that of the marketed formulation across isolated goat cornea, indicating the suitability of the nanosuspension formulation in the ophthalmic delivery of moxifloxacin. The optimised nano-suspension was found to be more active against S. aureus and P. aeruginosa compared to the marketed eye drops. PMID:23833723

Mudgil, Meetali; Pawar, Pravin K.

2013-01-01

172

Automated Segmentation and Object Classification of CT Images: Application to In Vivo Molecular Imaging of Avian Embryos  

PubMed Central

Background. Although chick embryogenesis has been studied extensively, there has been growing interest in the investigation of skeletogenesis. In addition to improved poultry health and minimized economic loss, a greater understanding of skeletal abnormalities can also have implications for human medicine. True in vivo studies require noninvasive imaging techniques such as high-resolution microCT. However, the manual analysis of acquired images is both time consuming and subjective. Methods. We have developed a system for automated image segmentation that entails object-based image analysis followed by the classification of the extracted image objects. For image segmentation, a rule set was developed using Definiens image analysis software. The classification engine was implemented using the WEKA machine learning tool. Results. Our system reduces analysis time and observer bias while maintaining high accuracy. Applying the system to the quantification of long bone growth has allowed us to present the first true in ovo data for bone length growth recorded in the same chick embryos. Conclusions. The procedures developed represent an innovative approach for the automated segmentation, classification, quantification, and visualization of microCT images. MicroCT offers the possibility of performing longitudinal studies and thereby provides unique insights into the morpho- and embryogenesis of live chick embryos. PMID:23997760

Schmidt, Jana; Zimmermann, Johannes; Saluz, Hans Peter

2013-01-01

173

Application of Raman spectroscopy for visualizing biochemical changes during peripheral nerve injury in vitro and in vivo.  

PubMed

Raman spectroscopy can be used for analysis of objects by detecting the vibrational spectrum using label-free methods. This imaging method was applied to analysis of peripheral nerve regeneration by examining the sciatic nerve in vitro and in vivo. Raman spectra of intact nerve tissue had three particularly important peaks in the range 2800-3000 cm-1. Spectra of injured sciatic nerves showed significant changes in the ratio of these peaks. Analysis of cellular spectra suggested that the spectrum for sciatic nerve tissue reflects the axon and myelin components of this tissue. Immunohistochemical analysis showed that the number of axons and the myelinated area were reduced at 7 days after injury and then increased by 28 days. The relative change in the axon to myelin ratio showed a similar initial increase, followed by a decrease at 28 days after injury. These changes correlated with the band intensity ratio and the changes in distribution of axon and myelin in Raman spectral analysis. Thus, our results suggest that label-free biochemical imaging with Raman spectroscopy can be used to detect turnover of axon and myelin in peripheral nerve regeneration. PMID:24281358

Morisaki, Shinsuke; Ota, Chikashi; Matsuda, Ken-ichi; Kaku, Natsuko; Fujiwara, Hiroyoshi; Oda, Ryo; Ishibashi, Hidenobu; Kubo, Toshikazu; Kawata, Mitsuhiro

2013-11-01

174

In vitro and in vivo studies on laser-activated gold nanorods for applications in photothermal therapies  

NASA Astrophysics Data System (ADS)

We review our experimental studies on near infrared laser-activated gold nanoparticles in the direct welding of connective tissues. In particular, we discuss the use of gold nanorods excited by diode laser radiation at 810 nm to mediate functional photothermal effects and weld eye's lens capsules and arteries. The preparation of biopolymeric matrices including gold nanorods is described as well, together with preliminary tests for their application in the closure of wounds in vessels and tendons. Finally we mention future perspectives on the use of these nanoparticles for applications in the therapy of cancer.

Pini, Roberto; Ratto, Fulvio; Matteini, Paolo; Centi, Sonia; Rossi, Francesca

2010-04-01

175

Application of an amine functionalized biopolymer in the colonic delivery of glycyrrhizin: a design and in vivo efficacy study.  

PubMed

In our current study, a newer amine functionalized guar gum derivative was studied for its efficacy in colonic drug delivery. Glycyrrhizic acid mono-ammonium salt was used as the model drug. Drug-loaded microparticles were formulated by ionic crosslinking using sodium tripolyphosphate. The Scanning Electron Microscopic study revealed spherical particles of sizes from 4.9 ± 3.8 ?m to 6.9 ± 3.9 ?m. The FT-IR studies presented a possible interaction between the drug and the polymer. The drug was encapsulated in amorphous form as observed from the powder X-Ray Diffraction studies. A cumulative drug release study was carried out in simulated gastric, intestinal, and colonic fluids. The cumulative drug release studies presented a burst release followed by a sustained release of the drug in simulated colonic fluid containing rat cecal contents. The drug-polymer ratio was optimised using a 3(2) factorial design by taking the amounts of glycyrrhizic acid (X1) and guar gum alkyl amine (X2) as the independant variables. The percent cumulative drug release at 240 mins (Q240), 720 mins (Q720), and at 1,440 mins (Q1440) were considered as the dependant variables. The efficacy of the optimized formulation was studied in a 2,4,6-trinitrobenzene sulfonic acid-induced rat colitis model. The tissue's nitric oxide, malondialdehyde, and myeloperoxidase activities were found to be much lower in the microparticle-treated group compared to free drug-treated group. The histology of the colonic tissue from the treated group of animals revealed almost no infiltration of inflammatory cells in the tissue for the microparticle-treated group of animals. The synthesized amine derivative of guar gum was found to be better in vitro with a better in vivo efficacy in the colonic delivery of glycyrrhizic acid monoammonium salt and can be considered as a newer modified biopolymer for colonic drug delivery. PMID:24482776

Kumar De, Amit; Datta, Sriparna; Mukherjee, Arup

2013-12-01

176

Application of an Amine Functionalized Biopolymer in the Colonic Delivery of Glycyrrhizin: A Design and In Vivo Efficacy Study  

PubMed Central

In our current study, a newer amine functionalized guar gum derivative was studied for its efficacy in colonic drug delivery. Glycyrrhizic acid mono-ammonium salt was used as the model drug. Drug-loaded microparticles were formulated by ionic crosslinking using sodium tripolyphosphate. The Scanning Electron Microscopic study revealed spherical particles of sizes from 4.9 ± 3.8 ?m to 6.9 ± 3.9 ?m. The FT-IR studies presented a possible interaction between the drug and the polymer. The drug was encapsulated in amorphous form as observed from the powder X-Ray Diffraction studies. A cumulative drug release study was carried out in simulated gastric, intestinal, and colonic fluids. The cumulative drug release studies presented a burst release followed by a sustained release of the drug in simulated colonic fluid containing rat cecal contents. The drug-polymer ratio was optimised using a 32 factorial design by taking the amounts of glycyrrhizic acid (X1) and guar gum alkyl amine (X2) as the independant variables. The percent cumulative drug release at 240 mins (Q240), 720 mins (Q720), and at 1,440 mins (Q1440) were considered as the dependant variables. The efficacy of the optimized formulation was studied in a 2,4,6-trinitrobenzene sulfonic acid-induced rat colitis model. The tissue’s nitric oxide, malondialdehyde, and myeloperoxidase activities were found to be much lower in the microparticle-treated group compared to free drug-treated group. The histology of the colonic tissue from the treated group of animals revealed almost no infiltration of inflammatory cells in the tissue for the microparticle-treated group of animals. The synthesized amine derivative of guar gum was found to be better in vitro with a better in vivo efficacy in the colonic delivery of glycyrrhizic acid monoammonium salt and can be considered as a newer modified biopolymer for colonic drug delivery. PMID:24482776

Kumar De, Amit; Datta, Sriparna; Mukherjee, Arup

2013-01-01

177

Clinical Application of In-Room Positron Emission Tomography for In Vivo Treatment Monitoring in Proton Radiation Therapy  

SciTech Connect

Purpose: The purpose of this study is to evaluate the potential of using in-room positron emission tomography (PET) for treatment verification in proton therapy and for deriving suitable PET scan times. Methods and Materials: Nine patients undergoing passive scattering proton therapy underwent scanning immediately after treatment with an in-room PET scanner. The scanner was positioned next to the treatment head after treatment. The Monte Carlo (MC) method was used to reproduce PET activities for each patient. To assess the proton beam range uncertainty, we designed a novel concept in which the measured PET activity surface distal to the target at the end of range was compared with MC predictions. The repositioning of patients for the PET scan took, on average, approximately 2 minutes. The PET images were reconstructed considering varying scan times to test the scan time dependency of the method. Results: The measured PET images show overall good spatial correlations with MC predictions. Some discrepancies could be attributed to uncertainties in the local elemental composition and biological washout. For 8 patients treated with a single field, the average range differences between PET measurements and computed tomography (CT) image-based MC results were <5 mm (<3 mm for 6 of 8 patients) and root-mean-square deviations were 4 to 11 mm with PET-CT image co-registration errors of approximately 2 mm. Our results also show that a short-length PET scan of 5 minutes can yield results similar to those of a 20-minute PET scan. Conclusions: Our first clinical trials in 9 patients using an in-room PET system demonstrated its potential for in vivo treatment monitoring in proton therapy. For a quantitative range prediction with arbitrary shape of target volume, we suggest using the distal PET activity surface.

Min, Chul Hee [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)] [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Zhu, Xuping [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States)] [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States); Winey, Brian A. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)] [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Grogg, Kira [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States)] [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States); Testa, Mauro [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)] [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); El Fakhri, Georges [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States)] [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States); Bortfeld, Thomas R.; Paganetti, Harald [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)] [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)

2013-05-01

178

Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study  

PubMed Central

Objective: Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters. Study Design: Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) on a surface of 4 cm2 with a Nd:YAG laser (VSP mode, 320 micrometer fiber, defocused mode) with different parameters. Temperatures were recorded before and after laser applications and after each pause in order to evaluate also the thermal relaxation of tissues. Results: At submucosal level, mean thermal increase was between 1.1°C and 13.2°C, at 1 mm depth between 1.1°C and 8.5°C, at 2 mm depth between 1.1°C and 6.8°C, at 4 mm depth between 1.0°C and 5.3°C. Temperature decrease during the rest time period was variable between 0°C and 2.5°C. Conclusions: Temperatures reached during clinical procedures with parameters reported in the literature in biostimulation protocols (1.25-2 Watts) for the five minutes of application are not dangerous for biological structures. The decrease in temperature during the rest time period is less considerable in the bone in comparison to oral mucosa. Key words:Nd:YAG laser, thermal increase, thermocouple, thermal camera, low level laser therapy. PMID:22322506

Vescovi, Paolo; Fornaini, Carlo; Rocca, Jean P.; Nammour, Samir

2012-01-01

179

The application of micro-CT in monitoring bone alterations in tail-suspended rats in vivo  

NASA Astrophysics Data System (ADS)

Osteopenia is a pathological process that affects human skeletal health not only on earth but also in long-time spaceflight. Micro-computed tomography (micro-CT) is a nondestructive method for assessing both bone quantity and bone quality. To investigate the characteristics of micro-CT on evaluating the microgravity-induced osteopenia (e.g. early detection time and the sensitive parameters), the bone loss process of tail-suspended rats was monitored by micro-CT in this study. 8-Week-old female Sprague Dawley rats were divided into two groups: tail suspension (TS) and control (CON). Volumetric bone mineral density (vBMD) and microstructure of the femur and tibia were evaluated in vivo by micro-CT at 0, 7, 14, 22 days. Biomechanical properties of the femur and tibia were determined by three-point bending test. The ash weight of bone was also investigated. The results showed that (1) bone loss in the proximal tibia appeared earlier than in the distal femur. (2) On day 7, the percent bone volume (BV/TV) of the tibia 15.44% decreased significantly, and the trabecular separation (Tb.Sp) 30.29% increased significantly in TS group, both of which were detected earlier than other parameters. (3) Biomechanical properties (e.g. femur, -22.4% maximum load and -23.75% Young’s modulus vs. CON) and ash weight of the femur and tibia decreased significantly in the TS group in comparison to CON group. (4) vBMD of the femur and tibia were clearly related to bone ash and dry weight (r = 0.75-0.87, p < 0.05). (5) BV/TV of both femur and tibia were clearly related to maximum load and Young’s modulus (r = 0.66-0.87, p < 0.05). Similarly, trabecular vBMD and BV/TV of the femur and tibia were clearly related to Young’s modulus (r = 0.73-0.89, p < 0.05). These indicated that BV/TV and Tb.Sp were more sensitive than other parameters for evaluating bone loss induced by tail suspension, moreover, trabecular vBMD and other parameters might be used to evaluate bone strength. Therefore, micro-CT is a reliable and sensitive method for predicting unloading-induced bone loss in small animals.

Luan, Hui-Qin; Sun, Lian-Wen; Huang, Yun-Fei; Wang, Ying; McClean, Colin J.; Fan, Yu-Bo

2014-06-01

180

Time-resolved singlet oxygen luminescence detection under photodynamic therapy relevant conditions: comparison of ex vivo application of two photosensitizer formulations  

NASA Astrophysics Data System (ADS)

Singlet oxygen plays a crucial role in photo-dermatology and photodynamic therapy (PDT) of cancer. Its direct observation by measuring the phosphorescence at 1270 nm, however, is still challenging due to the very low emission probability. It is especially challenging for the time-resolved detection of singlet oxygen kinetics in vivo which is of special interest for biomedical applications. Photosensitized generation of singlet oxygen, in pig ear skin as model for human skin, is investigated here. Two photosensitizers (PS) were topically applied to the pig ear skin and examined in a comparative study, which include the amphiphilic pheophorbide-a and the highly hydrophobic perfluoroalkylated zinc phthalocyanine (F64PcZn). Fluorescence microscopy indicates the exclusive accumulation of pheophorbide-a in the stratum corneum, while F64PcZn can also accumulate in deeper layers of the epidermis of the pig ear skin. The kinetics obtained with phosphorescence measurements show the singlet oxygen interaction with the PS microenvironment. Different generation sites of singlet oxygen correlate with the luminescence kinetics. The results show that singlet oxygen luminescence detection can be used as a diagnostic tool, not only for research, but also during treatment. The detection methodology is suitable for the monitoring of chemical quenchers' oxidation as well as O2 saturation at singlet oxygen concentration levels relevant to PDT treatment protocols.

Schlothauer, Jan C.; Hackbarth, Steffen; Jäger, Lutz; Drobniewski, Kai; Patel, Hemantbhai; Gorun, Sergiu M.; Röder, Beate

2012-11-01

181

Resistance after Chronic Application of the HDAC-Inhibitor Valproic Acid Is Associated with Elevated Akt Activation in Renal Cell Carcinoma In Vivo  

PubMed Central

Targeted drugs have significantly improved the therapeutic options for advanced renal cell carcinoma (RCC). However, resistance often develops, negating the benefit of these agents. In the present study, the molecular mechanisms of acquired resistance towards the histone deacetylase (HDAC) inhibitor valproic acid (VPA) in a RCC in vivo model were investigated. NMRI:nu/nu mice were transplanted with Caki-1 RCC cells and then treated with VPA (200 mg/kg/day). Controls remained untreated. Based on tumor growth dynamics, the mice were divided into “responders” and “non-responders” to VPA. Histone H3 and H4 acetylation and expression of cell signaling and cell cycle regulating proteins in the RCC mouse tumors were evaluated by Western blotting. Tumor growth of VPA responders was significantly diminished, whereas that of VPA non-responders even exceeded control values. Cdk1, 2 and 4 proteins were strongly enhanced in the non-responders. Importantly, Akt expression and activity were massively up-regulated in the tumors of the VPA non-responders. Chronic application (12 weeks) of VPA to Caki-1 cells in vitro evoked a distinct elevation of Akt activity and cancer cells no longer responded with cell growth reduction, compared to the short 2 week treatment. We assume that chronic use of an HDAC-inhibitor is associated with (re)-activation of Akt, which may be involved in resistance development. Consequently, combined blockade of both HDAC and Akt may delay or prevent drug resistance in RCC. PMID:23372654

Juengel, Eva; Makarevi?, Jasmina; Tsaur, Igor; Bartsch, Georg; Nelson, Karen; Haferkamp, Axel; Blaheta, Roman A.

2013-01-01

182

In vivo assessments of bioabsorbable AZ91 magnesium implants coated with nanostructured fluoridated hydroxyapatite by MAO/EPD technique for biomedical applications.  

PubMed

Although magnesium (Mg) is a unique biodegradable metal which possesses mechanical property similar to that of the natural bone and can be an attractive material to be used as orthopedic implants, its quick corrosion rate restricts its actual clinical applications. To control its rapid degradation, we have modified the surface of magnesium implant using fluoridated hydroxyapatite (FHA: Ca10(PO4)6OH2-xFx) through the combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) techniques, which was presented in our previous paper. In this article, the biocompatibility examinations were conducted on the coated AZ91 magnesium alloy by implanting it into the greater trochanter area of rabbits. The results of the in vivo animal test revealed a significant enhancement in the biocompatibility of FHA/MAO coated implant compared to the uncoated one. By applying the FHA/MAO coating on the AZ91 implant, the amount of weight loss and magnesium ion release in blood plasma decreased. According to the histological results, the formation of the new bone increased and the inflammation decreased around the implant. In addition, the implantation of the uncoated AZ91 alloy accompanied by the release of hydrogen gas around the implant; this release was suppressed by applying the coated implant. Our study exemplifies that the surface coating of magnesium implant using a bioactive ceramic such as fluoridated hydroxyapatite may improve the biocompatibility of the implant to make it suitable as a commercialized biomedical product. PMID:25579892

Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

2015-03-01

183

Universally applicable methods for monitoring response regulator aspartate phosphorylation both in vitro and in vivo using Phos-tag™ based reagents  

PubMed Central

Recent development of the phosphate chelator, Phos-tag™, together with Phos-tag™ pendant reagents, has provided new methods for detection of phosphorylated serine, threonine, tyrosine, and histidine residues in phosphoproteins. We have investigated the use of Phos-tag™ for detection and quantification of phospho-aspartate in response regulator proteins that function within two-component signaling systems. Alternative methods are especially important, as the labile nature of the acyl phosphate bond in response regulator proteins has restricted the application of many traditional methods of phosphoprotein analysis. We demonstrate that Phos-tag™ gel stain can be used to detect phospho-Asp in response regulators, and that Phos-tag™ acrylamide gel electrophoresis can be used to separate phosphorylated and unphosphorylated forms of response regulator proteins. The latter method, coupled to western blot analysis, enables detection of specific phosphorylated proteins in complex mixtures such as cell lysates. Standards of phosphorylated proteins can be used to correct for hydrolysis of the labile phospho-Asp bond that invariably occurs during analysis. We have employed Phos-tag™ methods to characterize the phosphorylation state of the Escherichia coli response regulator PhoB both in vitro, using purified protein, and in vivo, by analyzing lysates of cells grown under different conditions of induction of the PhoR/PhoB phosphate assimilation pathway. PMID:18328252

Barbieri, Christopher M.; Stock, Ann M.

2008-01-01

184

Expanding the Versatility of Mesoporous Silica Nanoparticles towards Drug Delivery for In-vitro, In-vivo and Clinical Applications  

NASA Astrophysics Data System (ADS)

The work covered in this thesis focuses on research developments in the mesoporous silica nanoparticle platform as a drug delivery vehicle for containment and controlled release of therapeutic agents to inhibit disease. Mesoporous silica is a very versatile material with a very robust structure that is easily modified both internally and externally to change its physical properties. Once modified, the silica nanoparticies can be loaded with therapeutic agents that can be isolated from interacting with their surroundings until an on command delivery signal is received. In this dissertation, first, application of a noninvasive externally controlled means of activation such as light activation and magnetically based heating have been investigated and achieved. Next, by altering the structure of rotaxanes based on azobenzene, steps towards a self-sealing light activated full rotaxane system have been developed. Then, through the manipulation of the particle structure as well as the internal pore environment of silica particle, the interaction between guest drug molecules and the particles has been better understood towards optimizing drug loading and release efficiency. Finally, surface modification of silica nanoparticles with biomolcules has been achieved and observed to increase the efficacy of the silica nanoparticle system in the cellular environment. A combination of all these areas of research results in the advancement of the mesoporous silica nanoparticle drug delivery system towards utilization within living organisms.

Ferris, Daniel Patrick

185

Ex vivo lung perfusion  

PubMed Central

Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. Its application in high-risk donor lungs has been successful and resulted in safe expansion of the donor pool. This article will: (I) review the technical details of EVLP; (II) the rationale behind the method; (III) report the worldwide clinical experience with the EVLP, including the Toronto technique and others; (IV) finally, discuss the growing literature on EVLP application for donation after cardiac death (DCD) lungs. PMID:25132972

Machuca, Tiago N.

2014-01-01

186

Clinical applications of a real-time scanning-slit confocal microscope designed for real-time observations of the in-vivo human cornea  

NASA Astrophysics Data System (ADS)

We describe a new, real-time, flying slit confocal microscope, that has unique features and imaging characteristics for in vivo human ocular imaging. In vivo real-time confocal microscopy is currently used to investigate the tear film, renewal of the ocular surface, the role of epithelial innervation in epithelial cell proliferation, wound healing, kinetics of drug penetration, the effects of laser refractive surgery on the keratocyte activation and distribution in the stroma, and the nature of endothelial defects. The following clinical examples will be presented and discussed: confocal microscopy of normal human basal and wing cells in the epithelium, confocal microscopy of lamellar and penetrating corneal grafts, confocal microscopy of corneal ulcer, confocal microscopy of scar formation after herpes keratitis, and confocal microscopy of corneal innervation. The use of scanning slit confocal microscopes has unique advantages over other instrumental systems based on pinhole-containing Nipkow disks (tandem-scanning confocal microscopes) for clinical in vivo confocal microscopy.

Masters, Barry R.

1995-05-01

187

Establishment of an Allo-Transplantable Hamster Cholangiocarcinoma Cell Line and Its Application for In Vivo Screening of Anti-Cancer Drugs  

PubMed Central

Opisthorchis viverrini (O. viverrini) is a well-known causative agent of cholangiocarcinoma (CCA) in humans. CCA is very resistant to chemotherapy and is frequently fatal. To understand the pathogenesis of CCA in humans, a rodent model was developed. However, the development of CCA in rodents is time-consuming and the xenograft-transplantation model of human CCA in immunodeficient mice is costly. Therefore, the establishment of an in vivo screening model for O. viverrini-associated CCA treatment was of interest. We developed a hamster CCA cell line, Ham-1, derived from the CCA tissue of O. viverrini-infected and N-nitrosodimethylamine-treated Syrian golden hamsters. Ham-1 has been maintained in Dulbecco's Modified Essential Medium supplemented with 10% fetal bovine serum for more than 30 subcultures. These cells are mostly diploid (2n=44) with some being polyploid. Tumorigenic properties of Ham-1 were demonstrated by allograft transplantation in hamsters. The transplanted tissues were highly proliferative and exhibited a glandular-like structure retaining a bile duct marker, cytokeratin 19. The usefulness of this for in vivo model was demonstrated by berberine treatment, a traditional medicine that is active against various cancers. Growth inhibitory effects of berberine, mainly by an induction of G1 cell cycle arrest, were observed in vitro and in vivo. In summary, we developed the allo-transplantable hamster CCA cell line, which can be used for chemotherapeutic drug testing in vitro and in vivo. PMID:24516278

Puthdee, Nattapong; Seubwai, Wunchana; Wonkchalee, Orasa; Kaewkong, Worasak; Juasook, Amornrat; Pinlaor, Somchai; Pairojkul, Chawalit; Wongkham, Chaisiri; Okada, Seiji; Boonmars, Thidarut; Wongkham, Sopit

2013-01-01

188

APPLICATION OF THE EPR SPIN-TRAPPING TECHNIQUE TO THE DETECTION OF RADICALS PRODUCED IN VIVO DURING INHALATION EXPOSURE OF RATS TO OZONE  

EPA Science Inventory

Ozone is known to induce lipid peroxidation of lung tissue, although no direct evidence of free radical formation has been reported. e have use the electron paramagnetic resonance (EPR) spin-trapping technique to search for free radicals produced in vivo by ozone exposure. he spi...

189

Behavior of Tip-Steerable Needles in ex vivo and in vivo Tissue  

PubMed Central

Robotic needle steering is a promising technique to improve the effectiveness of needle-based clinical procedures, such as biopsies and ablation, by computer-controlled, curved insertions of needles within solid organs. In this paper, we explore the capabilities, challenges, and clinical relevance of asymmetric-tip needle steering though experiments in ex vivo and in vivo tissue. We evaluate the repeatability of needle insertion in inhomogeneous biological tissue and compare ex vivo and in vivo needle curvature and insertion forces. Steerable needles curved more in kidney than in liver and prostate, likely due to differences in tissue properties. Pre-bent needles produced higher insertion forces in liver and more curvature in vivo than ex vivo. When compared to straight stainless steel needles, steerable needles did not cause a measurable increase in tissue damage and did not exert more force during insertion. The minimum radius of curvature achieved by pre-bent needles was 5.23 cm in ex vivo tissue, and 10.4 cm in in vivo tissue. The curvatures achieved by bevel tip needles were negligible for in vivo tissue. The minimum radius of curvature for bevel tip needles in ex vivo tissue was 16.4 cm; however, about half of the bevel tip needles had negligible curvatures. We also demonstrate a potential clinical application of needle steering by targeting and ablating overlapping regions of cadaveric canine liver. PMID:22711767

Majewicz, Ann; Marra, Steven P.; van Vledder, Mark G.; Lin, MingDe; Choti, Michael A.; Song, Danny Y.; Okamura, Allison M.

2012-01-01

190

Application of proteoglycan extracted from the nasal cartilage of salmon heads for ex vivo expansion of hematopoietic progenitor cells derived from human umbilical cord blood  

Microsoft Academic Search

Highly purified proteoglycan (PG) extracted from the nasal cartilage of salmon heads was applied to the ex vivo expansion of hematopoietic progenitor cells prepared from human umbilical cord blood in serum-free cultures supplemented\\u000a with the combination of early-acting cytokines, thrombopoietin (TPO), interleukin-3 (IL-3) and stem cell factor (SCF). PG\\u000a showed no promoting effects on the cell proliferation rate; however, they

Ikuo Kashiwakura; Kenji Takahashi; Keiichi Takagaki

2007-01-01

191

Application of biorelevant dissolution tests to the prediction of in vivo performance of diclofenac sodium from an oral modified-release pellet dosage form  

Microsoft Academic Search

In vitro biorelevant dissolution tests enabling the prediction of in vivo performance of an oral modified-release (MR) dosage form were developed in this study. In vitro dissolution of MR diclofenac sodium pellets containing 100mg active ingredient was evaluated under simulated pre- and postprandial conditions using USP Apparatus 3 (reciprocating cylinder, Bio-Dis) and 4 (flow-through cell) and results compared with compendial

Ekarat Jantratid; Vincenzo De Maio; Emanuela Ronda; Valentina Mattavelli; Maria Vertzoni; Jennifer B. Dressman

2009-01-01

192

Motion-artifact-robust, polarization-resolved second-harmonic-generation microscopy based on rapid polarization switching with electro-optic Pockells cell and its application to in vivo visualization of collagen fiber orientation in human facial skin  

PubMed Central

Polarization-resolved second-harmonic-generation (PR-SHG) microscopy is a powerful tool for investigating collagen fiber orientation quantitatively with low invasiveness. However, the waiting time for the mechanical polarization rotation makes it too sensitive to motion artifacts and hence has hampered its use in various applications in vivo. In the work described in this article, we constructed a motion-artifact-robust, PR-SHG microscope based on rapid polarization switching at every pixel with an electro-optic Pockells cell (PC) in synchronization with step-wise raster scanning of the focus spot and alternate data acquisition of a vertical-polarization-resolved SHG signal and a horizontal-polarization-resolved one. The constructed PC-based PR-SHG microscope enabled us to visualize orientation mapping of dermal collagen fiber in human facial skin in vivo without the influence of motion artifacts. Furthermore, it implied the location and/or age dependence of the collagen fiber orientation in human facial skin. The robustness to motion artifacts in the collagen orientation measurement will expand the application scope of SHG microscopy in dermatology and collagen-related fields. PMID:24761292

Tanaka, Yuji; Hase, Eiji; Fukushima, Shuichiro; Ogura, Yuki; Yamashita, Toyonobu; Hirao, Tetsuji; Araki, Tsutomu; Yasui, Takeshi

2014-01-01

193

Novel application of human periodontal ligament stem cells and water-soluble chitin for collagen tissue regeneration: in vitro and in vivo investigations.  

PubMed

Human periodontal ligament stem cells (hPDLSCs) have been proposed as an alternative to conventional cosmetic fillers because they display an innate ability to synthesize collagen. The aims of this study were to determine the effects of water-soluble chitin (WSC) on the proliferation and migration of hPDLSCs, and to quantify collagen synthesis in vitro and in vivo compared with human adipose-derived stem cell (hADSC)s. hPDLSCs were isolated from healthy extracted teeth, and the cell proliferation and cell migration capacities of untreated hPDLSCs (control group) and WSC-treated hPDLSCs (test group) were compared. Insoluble/soluble collagen synthesis were also assessed, and collagen related markers were evaluated including lysyl oxidase (LOX), lysyl oxidase like (LOXL)1, LOXL2, and hydroxyproline. In vivo collagen formation was examined by transplanting hyaluronic acid as a cell carrier into the subcutaneous pockets of immunocompromised mice in the control and test groups; histology and immunohistochemistry analyses were performed 4 (n=4) and 8 (n=4) weeks later. There was a dose-dependent enhancement of hPDLSCs proliferation in the test group, and a concomitant reduction in cell migration. The amount of insoluble collagen formed was greater in the test group than in the control group (p<0.05), whereas soluble collagen formation was significantly reduced in the test group (p<0.05). The histology and immunohistochemistry results revealed that the amount of collagen formed in vivo was greater in WSC-treated hPDLSCs than in the control cells at 4 and 8 weeks (p<0.05), and histometric analysis at 8 weeks revealed that enhancement of collagen formation by hPDLSCs was greater than by hADSCs. These results indicate that WSC modulates the properties of hPDLSCs, rendering them more suitable for cosmetic soft-tissue augmentation. PMID:21981356

Jung, Im Hee; Park, Jung Chul; Kim, Jane C; Jeon, Dong Won; Choi, Seong Ho; Cho, Kyoo Sung; Im, Gun Il; Kim, Byung Soo; Kim, Chang Sung

2012-03-01

194

Development of a disposable maglev centrifugal blood pump intended for one-month support in bridge-to-bridge applications: in vitro and initial in vivo evaluation.  

PubMed

MedTech Dispo, a disposable maglev centrifugal blood pump with two degrees of freedom magnetic suspension and radial magnetic coupling rotation, has been developed for 1-month extracorporeal circulatory support. As the first stage of a two-stage in vivo evaluation, 2-week evaluation of a prototype MedTech Dispo was conducted. In in vitro study, the pump could produce 5 L/min against 800 mm Hg and the normalized index of hemolysis was 0.0054 +/- 0.0008 g/100 L. In in vivo study, the pump, with its blood-contacting surface coated with biocompatible 2-methacryloyloxyethyl phosphorylcholine polymer, was implanted in seven calves in left heart bypass. Pump performance was stable with a mean flow of 4.49 +/- 0.38 L/min at a mean speed of 2072.1 +/- 64.5 rpm. The maglev control revealed its stability in rotor position during normal activity by the calves. During 2 weeks of operation in two calves which survived the intended study period, no thrombus formation was seen inside the pump and levels of plasma free hemoglobin were maintained below 4 mg/dL. Although further experiments are required, the pump demonstrated the potential for sufficient and reliable performance and biocompatibility in meeting the requirements for cardiopulmonary bypass and 1-week circulatory support. PMID:19775262

Someya, Takeshi; Kobayashi, Mariko; Waguri, Satoshi; Ushiyama, Tomohiro; Nagaoka, Eiki; Hijikata, Wataru; Shinshi, Tadahiko; Arai, Hirokuni; Takatani, Setsuo

2009-09-01

195

3D Compressed Sensing for Highly Accelerated Hyperpolarized 13C MRSI With In Vivo Applications to Transgenic Mouse Models of Cancer  

PubMed Central

High polarization of nuclear spins in liquid state through hyperpolarized technology utilizing dynamic nuclear polarization has enabled the direct monitoring of 13C metabolites in vivo at a high signal-to-noise ratio. Acquisition time limitations due to T1 decay of the hyperpolarized signal require accelerated imaging methods, such as compressed sensing, for optimal speed and spatial coverage. In this paper, the design and testing of a new echo-planar 13C three-dimensional magnetic resonance spectroscopic imaging (MRSI) compressed sensing sequence is presented. The sequence provides up to a factor of 7.53 in acceleration with minimal reconstruction artifacts. The key to the design is employing x and y gradient blips during a fly-back readout to pseudorandomly undersample kf-kx-ky space. The design was validated in simulations and phantom experiments where the limits of undersampling and the effects of noise on the compressed sensing nonlinear reconstruction were tested. Finally, this new pulse sequence was applied in vivo in preclinical studies involving transgenic prostate cancer and transgenic liver cancer murine models to obtain much higher spatial and temporal resolution than possible with conventional echo-planar spectroscopic imaging methods. PMID:20017160

Hu, Simon; Lustig, Michael; Balakrishnan, Asha; Larson, Peder E. Z.; Bok, Robert; Kurhanewicz, John; Nelson, Sarah J.; Goga, Andrei; Pauly, John M.; Vigneron, Daniel B.

2010-01-01

196

EDITORIAL: Nanotechnology in vivo Nanotechnology in vivo  

NASA Astrophysics Data System (ADS)

Since the development of x-rays the ability to image inside our bodies has provided medicine with a potent diagnostic tool, as well as fascinating us with the eerie evidence of our mechanistic mortality. In December 2008 Osamu Shimomura, Martin Chalfie and Roger Y Tsien received a Nobel Prize for the discovery and development of the green fluorescent protein. The award recognised a new discovery that further facilitated our abilities to follow cellular activities and delve deeper into the workings of living organisms. Since the first observation of green fluorescent protein in jelly fish over thirty years ago, quantum dots have emerged as a potential alternative tool for imaging [1]. The advantages of quantum dots over organic dyes and fluorescent proteins include intense luminescence, high molar extinction coefficient, resistance to photobleaching, and broad excitation with narrow emission bands. However, one drawback for biological applications has been the layer of hydrophobic organic ligands often present at the surface as a result of the synthesis procedures. One solution to improve the solubility of quantum dots has been to conjugate them with a hydrophilic substance, as reported by Nie et al [2]. Chitosan is a hydrophilic, non-toxic, biocompatible and biodegradable substance and has been conjugated with quantum dots such as CdSe-ZnS [2] for bioassays and intracellular labelling. As well as luminescence, different nanoparticles present a variety of exceptional properties that render them useful in a range of bio applications, including MRI, drug delivery and cancer hyperthermia therapy. The ability to harness these various attributes in one system was reported by researchers in China, who incorporated magnetic nanoparticles, fluorescent quantum dots and pharmaceutical drugs into chitosan nanoparticles for multifunctional smart drug delivery systems [3]. More recently silicon quantum dots have emerged as a less cytotoxic alternative to CdSe for bio-imaging labels [4]. A surface hydroxyl group renders silicon quantum dots soluble in water and the photoluminescence can be made stable with oxygen-passivation. In addition, researchers in Japan have demonstrated how the initially modest yield in the preparation of silicon quantum dots can be improved to tens of milligrams per batch, thus further promoting their application in bio-imaging [5]. In the search for non-toxic quantum dots, researchers at the Amrita Centre for Nanoscience in India have prepared heavy metal-free quantum dot bio-probes based on single phase ZnS [6]. The quantum dots are selectively doped with metals, transition metals and halides to provide tuneable luminescence properties, and they are surface conjugated with folic acid for cancer targeting. The quantum dots were demonstrated to be water-soluble, non-toxic in normal and cancer cell lines, and have bright, tuneable luminescence. So far most of the quantum dots developed for bio-imaging have had excitation and emission wavelengths in the visible spectrum, which is highly absorbed by tissue. This limits imaging with these quantum dots to superficial tissues. This week, researchers in China and the US reported work developing functionalized dots for in vivo tumour vasculature in the infrared part of the spectrum [7]. In addition the quantum dots were functionalised with glycine-aspartic acid (RGD) peptides, which target the vasculature of almost all types of growing tumours, unlike antibody- or aptamer-mediated targeting strategies that are specific to a particular cancer type. In this issue, researchers in China and the US demonstrate a novel type of contrast agent for ultrasonic tumour imaging [8]. Contrast-enhanced ultrasonic tumour imaging extends the diagnostic and imaging capabilities of traditional techniques. The use of nanoparticles as ultrasound contrast agents exploits the presence of open pores in the range of 380 to 780 nm in tumour blood vessels, which enhance the permeability and retention of nanoparticles in the tumour vasculature. However, previous reports on techniques to generate

Demming, Anna

2010-04-01

197

Visible light excitable Zn2+ fluorescent sensor derived from an intramolecular charge transfer fluorophore and its in vitro and in vivo application.  

PubMed

The UV- and sensor-induced interferences to living systems pose a barrier for in vivo Zn(2+) imaging. In this work, an intramolecular charge transfer (ICT) fluorophore of smaller aromatic plane, 4-amino-7-nitro-2,1,3-benzoxadiazole, was adopted to construct visible light excited fluorescent Zn(2+) sensor, NBD-TPEA. This sensor demonstrates a visible ICT absorption band, a large Stokes shift, and biocompatibility. It emits weakly (Phi = 0.003) without pH dependence at pH 7.1-10.1, and the lambda(ex) and lambda(em) are 469 (epsilon(469) = 2.1 x 10(4) M(-1) cm(-1)) and 550 nm, respectively. The NBD-TPEA displays distinct selective Zn(2+)-amplified fluorescence (Phi = 0.046, epsilon(469) = 1.4 x 10(4) M(-1) cm(-1)) with emission shift from 550 to 534 nm, which can be ascribed to the synergic Zn(2+) coordination by the outer bis(pyridin-2-ylmethyl)amine (BPA) and 4-amine. The Zn(2+) binding ratio of NBD-TPEA is 1:1. By comparison with its analogues NBD-BPA and NBD-PMA, which have no Zn(2+) affinity, the outer BPA in NBD-TPEA should be responsible for the Zn(2+)-induced photoinduced electron transfer blockage as well as for the enhanced Zn(2+) binding ability of 4-amine. Successful intracellular Zn(2+) imaging on living cells with NBD-TPEA staining exhibited a preferential accumulation at lysosome and Golgi with dual excitability at either 458 or 488 nm. The intact in vivo Zn(2+) fluorescence imaging on zebrafish embryo or larva stained with NBD-TPEA revealed two zygomorphic luminescent areas around its ventricle which could be related to the Zn(2+) storage for the zebrafish development. Moreover, high Zn(2+) concentration in the developing neuromasters of zebrafish can be visualized by confocal fluorescence imaging. This study demonstrates a novel strategy to construct visible light excited Zn(2+) fluorescent sensor based on ICT fluorophore other than xanthenone analogues. Current data show that NBD-TPEA staining can be a reliable approach for the intact in vivo Zn(2+) imaging of zebrafish larva as well as for the clarification of subcellular distribution of Zn(2+) in vitro. PMID:19138071

Qian, Fang; Zhang, Changli; Zhang, Yumin; He, Weijiang; Gao, Xiang; Hu, Ping; Guo, Zijian

2009-02-01

198

Patient-derived Models of Human Breast Cancer: Protocols for In vitro and In vivo Applications in Tumor Biology and Translational Medicine  

PubMed Central

Research models that replicate the diverse genetic and molecular landscape of breast cancer are critical for developing the next generation therapeutic entities that can target specific cancer subtypes. Patient-derived tumorgrafts, generated by transplanting primary human tumor samples into immune-compromised mice, are a valuable method to model the clinical diversity of breast cancer in mice, and are a potential resource in personalized medicine. Primary tumorgrafts also enable in vivo testing of therapeutics and make possible the use of patient cancer tissue for in vitro screens. Described in this unit are a variety of protocols including tissue collection, biospecimen tracking, tissue processing, transplantation, and 3-dimensional culturing of xenografted tissue, that enable use of bona fide uncultured human tissue in designing and validating cancer therapies. PMID:23456611

DeRose, Yoko S.; Gligorich, Keith M.; Wang, Guoying; Georgelas, Ann; Bowman, Paulette; Courdy, Samir J.; Welm, Alana L.; Welm, Bryan E.

2013-01-01

199

Application of proteoglycan extracted from the nasal cartilage of salmon heads for ex vivo expansion of hematopoietic progenitor cells derived from human umbilical cord blood.  

PubMed

Highly purified proteoglycan (PG) extracted from the nasal cartilage of salmon heads was applied to the ex vivo expansion of hematopoietic progenitor cells prepared from human umbilical cord blood in serum-free cultures supplemented with the combination of early-acting cytokines, thrombopoietin (TPO), interleukin-3 (IL-3) and stem cell factor (SCF). PG showed no promoting effects on the cell proliferation rate; however, they promoted the generation of progenitor cells for granulocyte-macrophages, erythrocytes and/or megakaryocytes in culture with TPO alone or SCF plus TPO. However, no promoting effect was observed in a combination of IL-3 plus SCF, which showed the highest cell proliferation rate. PG failed to promote the generation of mixed colony-forming units (i.e. the relatively immature cells in hematopoiesis). These results suggest that PG acts on the relatively mature stem/progenitor cells, and may function as a regulatory factor in the differentiation pathway of hematopoiesis. PMID:17393303

Kashiwakura, Ikuo; Takahashi, Kenji; Takagaki, Keiichi

2007-07-01

200

Development of a liquid chromatographic method for the quantification of paromomycin. Application to in vitro release and ex vivo permeation studies  

NASA Astrophysics Data System (ADS)

We have developed a reversed phase high performance liquid chromatography pulsed amperometric detection (RPHPLC-PAD) method for the determination of paromomycin. It is sensitive, repeatable, and selective without the pretreatment step. Trifluoroacetic acid-water was utilized as the eluent and detected by PAD under NaOH alkaline conditions. The paromomycin detection limit (S/N = 3.3) was 2 ?g mL-1 and the quantification limit (S/N = 10) was 6 ?g mL-1. Coefficients of linear regression were higher than 0.99 for concentrations between 6.25 and 200 ?g mL-1. The intra and inter-day precision (RSD) was less than 6.5%. The average recoveries were 97.53-102.01%. The proposed HPLC-PAD method presented advantageous performance characteristics and it can be considered suitable for the evaluation of paromomycin loaded nanogel formulation in ex vivo permeation and in vitro release studies.

Pujol-Brugués, A.; Calpena-Campmany, A. C.; Riera-Lizandra, C.; Halbaut-Bellowa, L.; Clares-Naveros, B.

2014-12-01

201

Detection of soluble co-factor dependent protein expression in vivo: application to the 4'-phosphopantetheinyl transferase PptT from Mycobacterium tuberculosis.  

PubMed

The need for early-on diagnostic tools to assess the folding and solubility of expressed protein constructs in vivo is of great interest when dealing with recalcitrant proteins. In this paper, we took advantage of the picomolar sensitivity of the bipartite GFP1-10/GFP11 system to investigate the solubility of the Mycobacterium tuberculosis 4'-phosphopantetheinyl transferase PptT, an enzyme essential for the viability of the tubercle bacillus. In vivo and in vitro complementation assays clearly showed the improved solubility of the full-length PptT compared to its N- and C-terminally truncated counterparts. However, initial attempts to purify the full-length enzyme overexpressed in Escherichia coli cells were hampered by aggregation issues overtime that caused the protein to precipitate within hours. The fact that the naturally occurring Coenzyme A and Mg(2+), essentials for PptT to carry out its function, could play a role in stabilizing the enzyme was confirmed using DSF experiments. In vitro activity assays were performed using the ACP substrate from the type I polyketide synthase PpsC from M. tuberculosis, a 2188 amino-acid enzyme that plays a major role in the virulence and pathogenicity of this microbial pathogen. We selected the most soluble and compact ACP fragment (2042-2188), identified by genetic selection of in-frame fragments from random library experiments, to monitor the transfer of the P-pant moiety from Coenzyme A onto a conserved serine residue of this ACP domain. PMID:23916562

Rottier, Karine; Faille, Alexandre; Prudhomme, Thomas; Leblanc, Cécile; Chalut, Christian; Cabantous, Stéphanie; Guilhot, Christophe; Mourey, Lionel; Pedelacq, Jean-Denis

2013-09-01

202

Effects of In Vitro Low Oxygen Tension Preconditioning of Adipose Stromal Cells on Their In Vivo Chondrogenic Potential: Application in Cartilage Tissue Repair  

PubMed Central

Purpose Multipotent stromal cell (MSC)-based regenerative strategy has shown promise for the repair of cartilage, an avascular tissue in which cells experience hypoxia. Hypoxia is known to promote the early chondrogenic differentiation of MSC. The aim of our study was therefore to determine whether low oxygen tension could be used to enhance the regenerative potential of MSC for cartilage repair. Methods MSC from rabbit or human adipose stromal cells (ASC) were preconditioned in vitro in control or chondrogenic (ITS and TGF-?) medium and in 21 or 5% O2. Chondrogenic commitment was monitored by measuring COL2A1 and ACAN expression (real-time PCR). Preconditioned rabbit and human ASC were then incorporated into an Si-HPMC hydrogel and injected (i) into rabbit articular cartilage defects for 18 weeks or (ii) subcutaneously into nude mice for five weeks. The newly formed tissue was qualitatively and quantitatively evaluated by cartilage-specific immunohistological staining and scoring. The phenotype of ASC cultured in a monolayer or within Si-HPMC in control or chondrogenic medium and in 21 or 5% O2 was finally evaluated using real-time PCR. Results/Conclusions 5% O2 increased the in vitro expression of chondrogenic markers in ASC cultured in induction medium. Cells implanted within Si-HPMC hydrogel and preconditioned in chondrogenic medium formed a cartilaginous tissue, regardless of the level of oxygen. In addition, the 3D in vitro culture of ASC within Si-HPMC hydrogel was found to reinforce the pro-chondrogenic effects of the induction medium and 5% O2. These data together indicate that although 5% O2 enhances the in vitro chondrogenic differentiation of ASC, it does not enhance their in vivo chondrogenesis. These results also highlight the in vivo chondrogenic potential of ASC and their potential value in cartilage repair. PMID:23638053

Gauthier, Olivier; Lesoeur, Julie; Sourice, Sophie; Masson, Martial; Fellah, Borhane Hakim; Geffroy, Olivier; Lallemand, Elodie; Weiss, Pierre

2013-01-01

203

FRET excited ratiometric oxygen sensing in living tissue  

PubMed Central

Dynamic analysis of oxygen (O2) has been limited by the lack of a real-time, quantitative, and biocompatible sensor. To address these demands, we designed a ratiometric optode matrix consisting of the phosphorescence quenching dye platinum (II) octaethylporphine ketone (PtOEPK) and nanocystal quantum dots (NQDs), which when embedded within an inert polymer matrix allows long-term pre-designed excitation through fluorescence resonance energy transfer (FRET). Depositing this matrix on various glass substrates allowed the development of a series of optical sensors able to measure interstitial oxygen concentration [O2] with several hundred millisecond temporal resolution in varying biological microdomains of active brain tissue. PMID:23333398

Ingram, Justin M.; Zhang, Chunfeng; Xu, Jian; Schiff, Steven J.

2013-01-01

204

Supramolecular quantum dot-porphyrin assemblies for biological oxygen sensing  

E-print Network

Generating metabolic profiles of tumors provides a spatiotemporal map of the concentration of key species to assess and quantify tumor growth, metabolism, and response to therapy. Because the tumor microenvironment is ...

Lemon, Christopher M. (Christopher Michael)

2013-01-01

205

Iron and oxygen sensing: a tale of 2 interacting elements?  

PubMed

Iron and oxygen metabolism are intimately linked with one another. A change in the level of either metabolite results in activation of common pathways. At the heart of these responses lies a group of iron and oxygen dependent enzymes called prolyl hydroxylases. Prolyl hydroxylases (PHDs) require both iron and oxygen for optimal activity and their biological activity is to carry out the critical post-translational modification of the addition of a hydroxyl group to specific proline residues within Hypoxia Inducible Factor (HIFs)-well known transcription factors originally thought to regulate responses to hypoxia but which are now known to regulate key iron metabolism proteins too. The addition of the hydroxyl group ultimately leads to the unbiquitylation and destruction of HIFs, thus PHDs control appropriate HIF transcriptional responses depending on cellular oxygen or iron levels. There are two major HIFs; HIF1? and HIF2?. In terms of responses to iron HIF2? is of major importance in key tissues such as the intestine where several iron transporters (Ferroportin, Dcytb) contain HREs within their promoters which bind HIF2?. Furthermore the recent discovery that HIF2? contains a 5' iron responsive element (IRE) has underlined the importance of HIF2? as a major player in iron metabolism. This review brings together recent findings with regard to the HIF2?/IRP network as well as other aspects of iron sensing in cells and tissues. PMID:25385426

Simpson, Robert J; McKie, Andrew T

2015-02-11

206

Oxygen-sensing persistent sodium channels in rat hippocampus  

PubMed Central

Persistent sodium channel activity was recorded before and during hypoxia from cell-attached and inside-out patches obtained from cultured hippocampal neurons at a pipette potential (Vp) of +30 mV. Average mean current (I?) of these channels was very low under normoxic conditions and was similar in cell-attached and excised inside-out patches (-0.018 ± 0.010 and -0.025 ± 0.008 pA, respectively, n = 24). Hypoxia increased the activity of persistent sodium channels in 10 cell-attached patches (I’ increased from -0.026 ± 0.016 pA in control to -0.156 ± 0.034 pA during hypoxia, n = 4, P = 0.013). The increased persistent sodium channel activity was most prominent at a VP between +70 and +30 mV (membrane potential, Vm = -70 to -30 mV) and could be blocked by lidocaine, TTX or R56865 (n = 5). Sodium cyanide (NaCN, 5 mM; 0.5-5 min) increased persistent sodium channel activity in cell-attached patches (n = 3) in a similar manner. Hypoxia also increased sodium channel activity in inside-out patches from hippocampal neurons. Within 2-4 min of exposure to hypoxia, I? had increased 9-fold to -0.18 ± 0.04 pA (n = 21, P = 0.001). Sodium channel activity increased further with longer exposures to hypoxia. The hypoxia-induced sodium channel activity in inside-out patches could be inhibited by exposure to 10-100 ?M lidocaine applied via the bath solution (I? = -0.03 ± 0.01 pA, n = 8) or by perfusion of the pipette tip with 1 ?M TTX (I? = -0.01 ± 0.01 pA, n = 3). The reducing agent dithiothreitol (DTT, 2-5 mM) rapidly abolished the increase in sodium channel activity caused by hypoxia in excised patches (I’ = -0.01 ± 0.01 pA, n = 4). Similarly, reduced glutathione (GSH, 5-20 mM) also reversed the hypoxia-induced increase in sodium channel activity (I’ = -0.02 ± 0.02 pA, n = 5). These results suggest that persistent sodium channels in neurons can sense O2 levels in excised patches of plasma membrane. Hypoxia triggers an increase in sodium channel activity. The redox reaction involved in increasing the sodium channel activity probably occurs in an auxiliary regulatory protein, co-localized in the plasma membrane. PMID:11080255

Hammarström, Anna K M; Gage, Peter W

2000-01-01

207

Hydroxylation of HIF-1: Oxygen Sensing at the Molecular Level  

NSDL National Science Digital Library

The ability to sense and respond to changes in oxygenation represents a fundamental property of all metazoan cells. The discovery of the transcription factor HIF-1 has led to the identification of protein hydroxylation as a mechanism by which changes in PO2 are transduced to effect changes in gene expression.

MD/PhD Gregg L. Semenza (Institute of Genetic Medicine, The Johns Hopkins University School of Medicine Departments of Pediatrics, Medicine, Oncology, and Radiation Oncology)

2004-08-01

208

Phosphorescent semiconductor nanocrystals and proteins for biological oxygen sensing  

E-print Network

Oxygen is required for cellular respiration by all complex life making it a key metabolic profiling factor in biological systems. Tumors are defined by hypoxia (low pO2), which has been shown to influence response to ...

McLaurin, Emily J. (Emily Jane)

2011-01-01

209

Multimodal Mn-doped I-III-VI quantum dots for near infrared fluorescence and magnetic resonance imaging: from synthesis to in vivo application  

NASA Astrophysics Data System (ADS)

The development of sensitive multimodal contrast agents is a key issue to provide better global, multi-scale images for diagnostic or therapeutic purposes. Here we present the synthesis of Zn-Cu-In-(S, Se)/Zn1-xMnxS core-shell quantum dots (QDs) that can be used as markers for both near-infrared fluorescence imaging and magnetic resonance imaging (MRI). We first present the synthesis of Zn-Cu-In-(S, Se) cores coated with a thick ZnS shell doped with various proportions of Mn. Their emission wavelengths can be tuned over the NIR optical window suitable for deep tissue imaging. The incorporation of manganese ions (up to a few thousand ions per QD) confers them a paramagnetic character, as demonstrated by structural analysis and electron paramagnetic resonance spectroscopy. These QDs maintain their optical properties after transfer to water using ligand exchange. They exhibit T1-relaxivities up to 1400 mM-1 [QD] s-1 at 7 T and 300 K. We finally show that these QDs are suitable multimodal in vivo probes and demonstrate MRI and NIR fluorescence detection of regional lymph nodes in mice.The development of sensitive multimodal contrast agents is a key issue to provide better global, multi-scale images for diagnostic or therapeutic purposes. Here we present the synthesis of Zn-Cu-In-(S, Se)/Zn1-xMnxS core-shell quantum dots (QDs) that can be used as markers for both near-infrared fluorescence imaging and magnetic resonance imaging (MRI). We first present the synthesis of Zn-Cu-In-(S, Se) cores coated with a thick ZnS shell doped with various proportions of Mn. Their emission wavelengths can be tuned over the NIR optical window suitable for deep tissue imaging. The incorporation of manganese ions (up to a few thousand ions per QD) confers them a paramagnetic character, as demonstrated by structural analysis and electron paramagnetic resonance spectroscopy. These QDs maintain their optical properties after transfer to water using ligand exchange. They exhibit T1-relaxivities up to 1400 mM-1 [QD] s-1 at 7 T and 300 K. We finally show that these QDs are suitable multimodal in vivo probes and demonstrate MRI and NIR fluorescence detection of regional lymph nodes in mice. Electronic supplementary information (ESI) available: Determination of Mn content; magnetization measurements; additional TEM and spectroscopic data; additional NIR fluorescence image; MTT assay results. See DOI: 10.1039/c4nr02239d

Sitbon, Gary; Bouccara, Sophie; Tasso, Mariana; Francois, Aurélie; Bezdetnaya, Lina; Marchal, Frédéric; Beaumont, Marine; Pons, Thomas

2014-07-01

210

Prediction of in vivo radiation dose status in radiotherapy patients using ex vivo and in vivo gene expression signatures.  

PubMed

After a large-scale nuclear accident or an attack with an improvised nuclear device, rapid biodosimetry would be needed for triage. As a possible means to address this need, we previously defined a gene expression signature in human peripheral white blood cells irradiated ex vivo that predicts the level of radiation exposure with high accuracy. We now demonstrate this principle in vivo using blood from patients receiving total-body irradiation (TBI). Whole genome microarray analysis has identified genes responding significantly to in vivo radiation exposure in peripheral blood. A 3-nearest neighbor classifier built from the TBI patient data correctly predicted samples as exposed to 0, 1.25 or 3.75 Gy with 94% accuracy (P < 0.001) even when samples from healthy donor controls were included. The same samples were classified with 98% accuracy using a signature previously defined from ex vivo irradiation data. The samples could also be classified as exposed or not exposed with 100% accuracy. The demonstration that ex vivo irradiation is an appropriate model that can provide meaningful prediction of in vivo exposure levels, and that the signatures are robust across diverse disease states and independent sample sets, is an important advance in the application of gene expression for biodosimetry. PMID:21388269

Paul, Sunirmal; Barker, Christopher A; Turner, Helen C; McLane, Amanda; Wolden, Suzanne L; Amundson, Sally A

2011-03-01

211

The application of hyaluronic acid-derivatized carbon nanotubes in hematoporphyrin monomethyl ether-based photodynamic therapy for in vivo and in vitro cancer treatment  

PubMed Central

Carbon nanotubes (CNTs) have shown great potential in both photothermal therapy and drug delivery. In this study, a CNT derivative, hyaluronic acid-derivatized CNTs (HA-CNTs) with high aqueous solubility, neutral pH, and tumor-targeting activity, were synthesized and characterized, and then a new photodynamic therapy agent, hematoporphyrin monomethyl ether (HMME), was adsorbed onto the functionalized CNTs to develop HMME-HA-CNTs. Tumor growth inhibition was investigated both in vivo and in vitro by a combination of photothermal therapy and photodynamic therapy using HMME-HA-CNTs. The ability of HMME-HA-CNT nanoparticles to combine local specific photodynamic therapy with external near-infrared photothermal therapy significantly improved the therapeutic efficacy of cancer treatment. Compared with photodynamic therapy or photothermal therapy alone, the combined treatment demonstrated a synergistic effect, resulting in higher therapeutic efficacy without obvious toxic effects to normal organs. Overall, it was demonstrated that HMME-HA-CNTs could be successfully applied to photodynamic therapy and photothermal therapy simultaneously in future tumor therapy. PMID:23843694

Shi, Jinjin; Ma, Rourou; Wang, Lei; Zhang, Jing; Liu, Ruiyuan; Li, Lulu; Liu, Yan; Hou, Lin; Yu, Xiaoyuan; Gao, Jun; Zhang, Zhenzhong

2013-01-01

212

The application of hyaluronic acid-derivatized carbon nanotubes in hematoporphyrin monomethyl ether-based photodynamic therapy for in vivo and in vitro cancer treatment.  

PubMed

Carbon nanotubes (CNTs) have shown great potential in both photothermal therapy and drug delivery. In this study, a CNT derivative, hyaluronic acid-derivatized CNTs (HA-CNTs) with high aqueous solubility, neutral pH, and tumor-targeting activity, were synthesized and characterized, and then a new photodynamic therapy agent, hematoporphyrin monomethyl ether (HMME), was adsorbed onto the functionalized CNTs to develop HMME-HA-CNTs. Tumor growth inhibition was investigated both in vivo and in vitro by a combination of photothermal therapy and photodynamic therapy using HMME-HA-CNTs. The ability of HMME-HA-CNT nanoparticles to combine local specific photodynamic therapy with external near-infrared photothermal therapy significantly improved the therapeutic efficacy of cancer treatment. Compared with photodynamic therapy or photothermal therapy alone, the combined treatment demonstrated a synergistic effect, resulting in higher therapeutic efficacy without obvious toxic effects to normal organs. Overall, it was demonstrated that HMME-HA-CNTs could be successfully applied to photodynamic therapy and photothermal therapy simultaneously in future tumor therapy. PMID:23843694

Shi, Jinjin; Ma, Rourou; Wang, Lei; Zhang, Jing; Liu, Ruiyuan; Li, Lulu; Liu, Yan; Hou, Lin; Yu, Xiaoyuan; Gao, Jun; Zhang, Zhenzhong

2013-01-01

213

Application of Escherichia coli phage K1E DNA-dependent RNA polymerase for in vitro RNA synthesis and in vivo protein production in Bacillus megaterium.  

PubMed

Gene "7" of Escherichia coli phage K1E was proposed to encode a novel DNA-dependent RNA polymerase (RNAP). The corresponding protein was produced recombinantly, purified to apparent homogeneity via affinity chromatography, and successfully employed for in vitro RNA synthesis. Optimal assay conditions (pH 8, 37 degrees C, 10 mM magnesium chloride and 1.3 mM spermidine) were established. The corresponding promoter regions were identified on the phage genome and summarized in a sequence logo. Surprisingly, next to K1E promoters, the SP6 promoter was also recognized efficiently in vitro by K1E RNAP, while the T7 RNAP promoter was not recognized at all. Based on these results, a system for high-yield in vitro RNA synthesis using K1E RNAP was established. The template plasmid is a pUC18 derivative, which enables blue/white screening for positive cloning of the target DNA. Production of more than 5 microg of purified RNA per microgram plasmid DNA was achieved. Finally, in vivo protein production systems for Bacillus megaterium were established based on K1E and SP6 phage RNAP transcription. Up to 61.4 mg g (CDW) (-1) (K1E RNAP) of the reporter protein Gfp was produced in shaking flask cultures of B. megaterium. PMID:20596705

Stammen, Simon; Schuller, Franziska; Dietrich, Sylvia; Gamer, Martin; Biedendieck, Rebekka; Jahn, Dieter

2010-09-01

214

In Vivo Application of Sub-Second Spiral Chemical Shift Imaging (CSI) to Hyperpolarized 13C Metabolic Imaging: Comparison with Phase-Encoded CSI  

PubMed Central

A fast spiral chemical shift imaging (CSI) has been developed to address the challenge of the limited acquisition window in hyperpolarized 13C metabolic imaging. The sequence exploits the sparsity of the spectra and prior knowledge of resonance frequencies to reduce the measurement time by undersampling the data in the spectral domain. As a consequence, multiple reconstructions are necessary for any given data set as only frequency components within a selected bandwidth are reconstructed “in-focus” while components outside that band are severely blurred (“spectral tomosynthesis”). A variable-flip-angle scheme was used for optimal use of the longitudinal magnetization. The sequence was applied to sub-second metabolic imaging of the rat in vivo after injection of hyperpolarized [1-13C]-pyruvate on a clinical 3T MR scanner. The comparison with conventional CSI based on phase encoding showed similar signal-to-noise ratio (SNR) and spatial resolution in metabolic maps for the substrate and its metabolic products lactate, alanine, and bicarbonate, despite a 50-fold reduction in scan time for the spiral CSI acquisition. The presented results demonstrate that dramatic reductions in scan time are feasible in hyperpolarized 13C metabolic imaging without a penalty in SNR or spatial resolution. PMID:20346717

Mayer, Dirk; Yen, Yi-Fen; Levin, Yakir S.; Tropp, James; Pfefferbaum, Adolf; Hurd, Ralph E.; Spielman, Daniel M.

2010-01-01

215

In vivo application of sub-second spiral chemical shift imaging (CSI) to hyperpolarized 13C metabolic imaging: comparison with phase-encoded CSI.  

PubMed

A fast spiral chemical shift imaging (CSI) has been developed to address the challenge of the limited acquisition window in hyperpolarized (13)C metabolic imaging. The sequence exploits the sparsity of the spectra and prior knowledge of resonance frequencies to reduce the measurement time by undersampling the data in the spectral domain. As a consequence, multiple reconstructions are necessary for any given data set as only frequency components within a selected bandwidth are reconstructed "in-focus" while components outside that band are severely blurred ("spectral tomosynthesis"). A variable-flip-angle scheme was used for optimal use of the longitudinal magnetization. The sequence was applied to sub-second metabolic imaging of the rat in vivo after injection of hyperpolarized [1-(13)C]-pyruvate on a clinical 3T MR scanner. The comparison with conventional CSI based on phase encoding showed similar signal-to-noise ratio (SNR) and spatial resolution in metabolic maps for the substrate and its metabolic products lactate, alanine, and bicarbonate, despite a 50-fold reduction in scan time for the spiral CSI acquisition. The presented results demonstrate that dramatic reductions in scan time are feasible in hyperpolarized (13)C metabolic imaging without a penalty in SNR or spatial resolution. PMID:20346717

Mayer, Dirk; Yen, Yi-Fen; Levin, Yakir S; Tropp, James; Pfefferbaum, Adolf; Hurd, Ralph E; Spielman, Daniel M

2010-06-01

216

Fluorescent Multiblock ?-Conjugated Polymer Nanoparticles for In Vivo Tumor Targeting  

PubMed Central

Highly fluorescent multiblock conjugated polymer nanoparticles with folic acid surface ligands are highly effective for bioimaging and in vivo tumor targeting. The targeted nanoparticles were preferentially localized in tumor cells in vivo, thereby illustrating their potential for diagnostic and therapeutic applications. PMID:23794490

Ahmed, Eilaf; Morton, Stephen W.

2014-01-01

217

Fluorescence Glucose Detection: Advances Toward the Ideal In Vivo Biosensor  

Microsoft Academic Search

The importance of glucose monitoring for in vivo as well as for ex vivo applications has driven a vast number of scientific groups to pursue the development of an advanced glucose sensor. Such a sensor must be robust, versatile, and capable of the long-term, accurate and reproducible detection of glucose levels in various testing media. Among the different configurations and

Elizabeth A. Moschou; Bethel V. Sharma; Sapna K. Deo; Sylvia Daunert

2004-01-01

218

Computational design of in vivo biomarkers.  

PubMed

Fluorescent semiconductor nanocrystals (or quantum dots) are very promising agents for bioimaging applications because their optical properties are superior compared to those of conventional organic dyes. However, not all the properties of these quantum dots suit the stringent criteria of in vivo applications, i.e. their employment in living organisms that might be of importance in therapy and medicine. In our review, we first summarize the properties of an 'ideal' biomarker needed for in vivo applications. Despite recent efforts, no such hand-made fluorescent quantum dot exists that may be considered as 'ideal' in this respect. We propose that ab initio atomistic simulations with predictive power can be used to design 'ideal' in vivo fluorescent semiconductor nanoparticles. We briefly review such ab initio methods that can be applied to calculate the electronic and optical properties of very small nanocrystals, with extra emphasis on density functional theory (DFT) and time-dependent DFT which are the most suitable approaches for the description of these systems. Finally, we present our recent results on this topic where we investigated the applicability of nanodiamonds and silicon carbide nanocrystals for in vivo bioimaging. PMID:24651562

Somogyi, Bálint; Gali, Adam

2014-04-01

219

In vivo RNAi: Today and Tomorrow  

PubMed Central

SUMMARY RNA interference (RNAi) provides a powerful reverse genetics approach to analyze gene functions both in tissue culture and in vivo. Because of its widespread applicability and effectiveness it has become an essential part of the tool box kits of model organisms such as Caenorhabditis elegans, Drosophila, and the mouse. In addition, the use of RNAi in animals in which genetic tools are either poorly developed or nonexistent enables a myriad of fundamental questions to be asked. Here, we review the methods and applications of in vivo RNAi to characterize gene functions in model organisms and discuss their impact to the study of developmental as well as evolutionary questions. Further, we discuss the applications of RNAi technologies to crop improvement, pest control and RNAi therapeutics, thus providing an appreciation of the potential for phenomenal applications of RNAi to agriculture and medicine. PMID:20534712

Perrimon, Norbert; Ni, Jian-Quan; Perkins, Lizabeth

2010-01-01

220

In vitro, ex vivo, in vivo veritas.  

PubMed

In vitro assessments of inhaler performance are important in product development and quality control, but are not, as such, good predictors of performance in vivo. It is, however, possible to modify in vitro techniques so that they more closely resemble the in vivo situation. Measurements of fine-particle dose (defined as the amount of drug with an aerodynamic diameter less than 5 microm) by cascade impactor have shown that the measured fine-particle dose in vitro is highly dependent on the geometry of the inlet to the impactor, the fine-particle dose being considerably lower when the cast of a human throat (an "anatomical throat") is used than when a standard glass inlet is used. This difference is, however, less with a dry-powder inhaler such as Turbuhaler than with a pressurized metered-dose inhaler (pMDI). Furthermore, there is a good correlation between fine-particle dose measured in vitro and in vivo lung deposition, provided that an anatomically correct inlet is used for the in vitro determination. Studies in children have shown that the degree of lung deposition of budesonide, delivered via Turbuhaler, is of the same order of size as the in vitro fine-particle dose. No comparable data are available for pMDIs; however, since children are smaller than adults, it is likely that differences in lung deposition between Turbuhaler and pMDIs are probably greater in children than in adults. PMID:10422754

Borgström, L

1999-01-01

221

In Vivo skin hydration and anti-erythema effects of Aloe vera, Aloe ferox and Aloe marlothii gel materials after single and multiple applications  

PubMed Central

Objective: To investigate the skin hydrating and anti-erythema activity of gel materials from Aloe marlothii A. Berger and A. ferox Mill. in comparison to that of Aloe barbadensis Miller (Aloe vera) in healthy human volunteers. Materials and Methods: Aqueous solutions of the polisaccharidic fractions of the selected aloe leaf gel materials were applied to the volar forearm skin of female subjects. The hydration effect of the aloe gel materials were measured with a Corneometer® CM 825, Visioscan® VC 98 and Cutometer® dual MPA 580 after single and multiple applications. The Mexameter® MX 18 was used to determine the anti-erythema effects of the aloe material solutions on irritated skin areas. Results: The A. vera and A. marlothii gel materials hydrated the skin after a single application, whereas the A. ferox gel material showed dehydration effects compared to the placebo. After multiple applications all the aloe materials exhibited dehydration effects on the skin. Mexameter® readings showed that A. vera and A. ferox have anti-erythema activity similar to that of the positive control group (i.e. hydrocortisone gel) after 6 days of treatment. Conclusion: The polysaccharide component of the gel materials from selected aloe species has a dehydrating effect on the skin after multiple applications. Both A. vera and A. ferox gel materials showed potential to reduce erythema on the skin similar to that of hydrocortisone gel. PMID:24991119

Fox, Lizelle T.; du Plessis, Jeanetta; Gerber, Minja; van Zyl, Sterna; Boneschans, Banie; Hamman, Josias H.

2014-01-01

222

Elastography Using Multi-Stream GPU: An Application to Online Tracked Ultrasound Elastography, In-Vivo and the da Vinci Surgical System  

PubMed Central

A system for real-time ultrasound (US) elastography will advance interventions for the diagnosis and treatment of cancer by advancing methods such as thermal monitoring of tissue ablation. A multi-stream graphics processing unit (GPU) based accelerated normalized cross-correlation (NCC) elastography, with a maximum frame rate of 78 frames per second, is presented in this paper. A study of NCC window size is undertaken to determine the effect on frame rate and the quality of output elastography images. This paper also presents a novel system for Online Tracked Ultrasound Elastography (O-TRuE), which extends prior work on an offline method. By tracking the US probe with an electromagnetic (EM) tracker, the system selects in-plane radio frequency (RF) data frames for generating high quality elastograms. A novel method for evaluating the quality of an elastography output stream is presented, suggesting that O-TRuE generates more stable elastograms than generated by untracked, free-hand palpation. Since EM tracking cannot be used in all systems, an integration of real-time elastography and the da Vinci Surgical System is presented and evaluated for elastography stream quality based on our metric. The da Vinci surgical robot is outfitted with a laparoscopic US probe, and palpation motions are autonomously generated by customized software. It is found that a stable output stream can be achieved, which is affected by both the frequency and amplitude of palpation. The GPU framework is validated using data from in-vivo pig liver ablation; the generated elastography images identify the ablated region, outlined more clearly than in the corresponding B-mode US images. PMID:25541954

Deshmukh, Nishikant P.; Kang, Hyun Jae; Billings, Seth D.; Taylor, Russell H.; Hager, Gregory D.; Boctor, Emad M.

2014-01-01

223

One-pot hydrothermal synthesis of lanthanide ions doped one-dimensional upconversion submicrocrystals and their potential application in vivo CT imaging.  

PubMed

Multi-functional rare-earth Yb(3+) and Ln(3+) (Ln = Er, Tm and Ho) ions doped one-dimensional (1-D) upconversion submicrocrystals (NaYF(4) and NaGdF(4)) possessing upconversion luminescence, biocompatibility and magnetic properties have been synthesized by a one-pot hydrothermal method. Rare-earth Yb(3+) and Ln(3+) ions doped NaYF(4) microrods (~1 ?m in diameter, 3-5 ?m in length) exhibit porous properties, and the average pore sizes are ~28.2 nm. They show paramagnetism in the magnetic range of -60 to -2 kOe and 2 to 60 kOe at 300 K, and exhibit near superparamagnetic behaviour at the magnetic range of -2 to 2 kOe. Saturation magnetization was ~12.1 emu g(-1) at 2 K. The Yb(3+) and Ln(3+) ions doped NaGdF(4) submicrocrystals (~100 nm in diameter, 200-300 nm in length) show paramagnetism at 300 K, and exhibit superparamagnetic behaviour with a saturation magnetization of 129.2 emu g(-1) at 2 K. The magnetic properties of Yb(3+) and Ln(3+) ions doped 1-D upconversion submicrocrystals indicate they can be used for drug targeting under a magnetic field. Their unique upconversion emission (green for Yb(3+)/Er(3+) and blue for Yb(3+)/Tm(3+)) under 980 nm laser excitation indicate that they could be used for specific luminescent immunolabeling and imaging. MTT assays reveal that 1-D upconversion submicrocrystals have satisfactory bio-affinity, where the viability keeps in good state even at a concentration of 500 ?g mL(-1), which is much higher than the concentration usually used in cell labelling. Luminescent microscopy images show that the morphologies of the cytoskeleton and cell nucleus are well maintained after incubating different concentrations of 1-D upconversion submicrocrystals. After injecting upconversion submicrocrystals into the mice (tumor sites or back normal tissue), a clearly distinguished CT signal was observed, indicating the synthesized 1-D submicrocrystals are effective for CT imaging in vivo. PMID:23168841

Gao, Guo; Zhang, Chunlei; Zhou, Zhijun; Zhang, Xin; Ma, Jiebing; Li, Chao; Jin, Weilin; Cui, Daxiang

2013-01-01

224

One-pot hydrothermal synthesis of lanthanide ions doped one-dimensional upconversion submicrocrystals and their potential application in vivo CT imaging  

NASA Astrophysics Data System (ADS)

Multi-functional rare-earth Yb3+ and Ln3+ (Ln = Er, Tm and Ho) ions doped one-dimensional (1-D) upconversion submicrocrystals (NaYF4 and NaGdF4) possessing upconversion luminescence, biocompatibility and magnetic properties have been synthesized by a one-pot hydrothermal method. Rare-earth Yb3+ and Ln3+ ions doped NaYF4 microrods (~1 ?m in diameter, 3-5 ?m in length) exhibit porous properties, and the average pore sizes are ~28.2 nm. They show paramagnetism in the magnetic range of -60 to -2 kOe and 2 to 60 kOe at 300 K, and exhibit near superparamagnetic behaviour at the magnetic range of -2 to 2 kOe. Saturation magnetization was ~12.1 emu g-1 at 2 K. The Yb3+ and Ln3+ ions doped NaGdF4 submicrocrystals (~100 nm in diameter, 200-300 nm in length) show paramagnetism at 300 K, and exhibit superparamagnetic behaviour with a saturation magnetization of 129.2 emu g-1 at 2 K. The magnetic properties of Yb3+ and Ln3+ ions doped 1-D upconversion submicrocrystals indicate they can be used for drug targeting under a magnetic field. Their unique upconversion emission (green for Yb3+/Er3+ and blue for Yb3+/Tm3+) under 980 nm laser excitation indicate that they could be used for specific luminescent immunolabeling and imaging. MTT assays reveal that 1-D upconversion submicrocrystals have satisfactory bio-affinity, where the viability keeps in good state even at a concentration of 500 ?g mL-1, which is much higher than the concentration usually used in cell labelling. Luminescent microscopy images show that the morphologies of the cytoskeleton and cell nucleus are well maintained after incubating different concentrations of 1-D upconversion submicrocrystals. After injecting upconversion submicrocrystals into the mice (tumor sites or back normal tissue), a clearly distinguished CT signal was observed, indicating the synthesized 1-D submicrocrystals are effective for CT imaging in vivo.Multi-functional rare-earth Yb3+ and Ln3+ (Ln = Er, Tm and Ho) ions doped one-dimensional (1-D) upconversion submicrocrystals (NaYF4 and NaGdF4) possessing upconversion luminescence, biocompatibility and magnetic properties have been synthesized by a one-pot hydrothermal method. Rare-earth Yb3+ and Ln3+ ions doped NaYF4 microrods (~1 ?m in diameter, 3-5 ?m in length) exhibit porous properties, and the average pore sizes are ~28.2 nm. They show paramagnetism in the magnetic range of -60 to -2 kOe and 2 to 60 kOe at 300 K, and exhibit near superparamagnetic behaviour at the magnetic range of -2 to 2 kOe. Saturation magnetization was ~12.1 emu g-1 at 2 K. The Yb3+ and Ln3+ ions doped NaGdF4 submicrocrystals (~100 nm in diameter, 200-300 nm in length) show paramagnetism at 300 K, and exhibit superparamagnetic behaviour with a saturation magnetization of 129.2 emu g-1 at 2 K. The magnetic properties of Yb3+ and Ln3+ ions doped 1-D upconversion submicrocrystals indicate they can be used for drug targeting under a magnetic field. Their unique upconversion emission (green for Yb3+/Er3+ and blue for Yb3+/Tm3+) under 980 nm laser excitation indicate that they could be used for specific luminescent immunolabeling and imaging. MTT assays reveal that 1-D upconversion submicrocrystals have satisfactory bio-affinity, where the viability keeps in good state even at a concentration of 500 ?g mL-1, which is much higher than the concentration usually used in cell labelling. Luminescent microscopy images show that the morphologies of the cytoskeleton and cell nucleus are well maintained after incubating different concentrations of 1-D upconversion submicrocrystals. After injecting upconversion submicrocrystals into the mice (tumor sites or back normal tissue), a clearly distinguished CT signal was observed, indicating the synthesized 1-D submicrocrystals are effective for CT imaging in vivo. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr32850j

Gao, Guo; Zhang, Chunlei; Zhou, Zhijun; Zhang, Xin; Ma, Jiebing; Li, Chao; Jin, Weilin; Cui, Daxiang

2012-12-01

225

Bioluminescence imaging of myeloperoxidase activity in vivo.  

PubMed

The myeloperoxidase (MPO) system of activated phagocytes is central to normal host defense mechanisms, and dysregulated MPO contributes to the pathogenesis of inflammatory disease states ranging from atherosclerosis to cancer. Here we show that upon systemic administration, the small molecule luminol enables noninvasive bioluminescence imaging (BLI) of MPO activity in vivo. Luminol-BLI allowed quantitative longitudinal monitoring of MPO activity in animal models of acute dermatitis, mixed allergic contact hypersensitivity, focal arthritis and spontaneous large granular lymphocytic tumors. Bioluminescence colocalized with histological sites of inflammation and was totally abolished in gene-deleted Mpo(-/-) mice, despite massive tissue infiltration of neutrophils and activated eosinophils, indicating that eosinophil peroxidase did not contribute to luminol-BLI in vivo. Thus, luminol-BLI provides a noninvasive, specific and highly sensitive optical readout of phagocyte-mediated MPO activity in vivo and may enable new diagnostic applications in a wide range of acute and chronic inflammatory conditions. PMID:19305414

Gross, Shimon; Gammon, Seth T; Moss, Britney L; Rauch, Daniel; Harding, John; Heinecke, Jay W; Ratner, Lee; Piwnica-Worms, David

2009-04-01

226

Application of Carbon-Ion Beams or Gamma-Rays on Primary Tumors Does Not Change the Expression Profiles of Metastatic Tumors in an In Vivo Murine Model  

SciTech Connect

Purpose: To clarify how carbon-ion radiotherapy (C-ion) on primary tumors affects the characteristics of subsequently arising metastatic tumor cells. Methods and Materials: Mouse squamous cell carcinomas, NR-S1, in synergic C3H/HeMsNrs mice were irradiated with a single dose of 5-50 Gy of C-ion (290 MeV per nucleon, 6-cm spread-out Bragg peak) or {gamma}-rays ({sup 137}Cs source) as a reference beam. The volume of the primary tumors and the number of metastatic nodules in lung were studied, and histologic analysis and microarray analysis of laser-microdissected tumor cells were also performed. Results: Including 5 Gy of C-ion and 8 Gy of {gamma}-rays, which did not inhibit the primary tumor growth, all doses used in this study inhibited lung metastasis significantly. Pathologic findings showed no difference among the metastatic tumor nodules in the nonirradiated, C-ion-irradiated, and {gamma}-ray-irradiated groups. Clustering analysis of expression profiles among metastatic tumors and primary tumors revealed a single cluster consisting of metastatic tumors different from their original primary tumors, indicating that the expression profiles of the metastatic tumor cells were not affected by the local application of C-ion or {gamma}-ray radiotherapy. Conclusion: We found no difference in the incidence and histology, and only small differences in expression profile, of distant metastasis between local C-ion and {gamma}-ray radiotherapy. The application of local radiotherapy per se or the type of radiotherapy applied did not influence the transcriptional changes caused by metastasis in tumor cells.

Tamaki, Tomoaki [RadGenomics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi, Gunma (Japan); Iwakawa, Mayumi [RadGenomics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)], E-mail: mayumii@nirs.go.jp; Ohno, Tatsuya; Imadome, Kaori; Nakawatari, Miyako; Sakai, Minako; Tsujii, Hirohiko [RadGenomics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Nakano, Takashi [Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi, Gunma (Japan); Imai, Takashi [RadGenomics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan)

2009-05-01

227

Application of the Principles of Systems Biology and Wiener’s Cybernetics for Analysis of Regulation of Energy Fluxes in Muscle Cells in Vivo  

PubMed Central

The mechanisms of regulation of respiration and energy fluxes in the cells are analyzed based on the concepts of systems biology, non-equilibrium steady state kinetics and applications of Wiener’s cybernetic principles of feedback regulation. Under physiological conditions cardiac function is governed by the Frank-Starling law and the main metabolic characteristic of cardiac muscle cells is metabolic homeostasis, when both workload and respiration rate can be changed manifold at constant intracellular level of phosphocreatine and ATP in the cells. This is not observed in skeletal muscles. Controversies in theoretical explanations of these observations are analyzed. Experimental studies of permeabilized fibers from human skeletal muscle vastus lateralis and adult rat cardiomyocytes showed that the respiration rate is always an apparent hyperbolic but not a sigmoid function of ADP concentration. It is our conclusion that realistic explanations of regulation of energy fluxes in muscle cells require systemic approaches including application of the feedback theory of Wiener’s cybernetics in combination with detailed experimental research. Such an analysis reveals the importance of limited permeability of mitochondrial outer membrane for ADP due to interactions of mitochondria with cytoskeleton resulting in quasi-linear dependence of respiration rate on amplitude of cyclic changes in cytoplasmic ADP concentrations. The system of compartmentalized creatine kinase (CK) isoenzymes functionally coupled to ANT and ATPases, and mitochondrial-cytoskeletal interactions separate energy fluxes (mass and energy transfer) from signalling (information transfer) within dissipative metabolic structures – intracellular energetic units (ICEU). Due to the non-equilibrium state of CK reactions, intracellular ATP utilization and mitochondrial ATP regeneration are interconnected by the PCr flux from mitochondria. The feedback regulation of respiration occurring via cyclic fluctuations of cytosolic ADP, Pi and Cr/PCr ensures metabolic stability necessary for normal function of cardiac cells. PMID:20479996

Guzun, Rita; Saks, Valdur

2010-01-01

228

In-vivo optical investigation of psoriasis  

NASA Astrophysics Data System (ADS)

Psoriasis is an autoimmune disease of the skin characterized by hyperkeratosis, hyperproliferation of the epidermis, inflammatory cell accumulation and increased dilatation of dermal papillary blood vessels. Cases of psoriasis were investigated in vivo with optical means in order to evaluate the potential of in vivo optical biopsy. A Polarization Multispectral Dermoscope was employed for the macroscopic observation. Features such as the 'dotted' blood vessels pattern was observed with high contrast. The average size of dot vessels in Psoriasis was measured to be 974 ?m2 which is much higher compared to healthy skin. High resolution image sections of the epidermis and the dermis were produced with a custom made Multiphoton Microscope. Imaging extended from the surface of the lesion down to the papillary dermis, at a depth of 200 ?m. In the epidermis, a characteristic morphology of the stratum corneum found only in Psoriasis was revealed. Additionally, the cytoplasmic area of the cells in the stratum spinosum layer was found to be smaller than normal. In the dermis the morphological features were more pronounced, where the elongated dermal papillae dominated the papillary layer. Their length exceeds 100?m, which is a far greater value compared to that of healthy skin. These in vivo observations are consistent with the ex vivo histopathological observations, supporting both the applicability and potentiality of multispectral dermoscopy and multiphoton microscopy in the field of in vivo optical investigation and biopsy of skin.

Kapsokalyvas, Dimitrios; Cicchi, Riccardo; Bruscino, Nicola; Alfieri, Domenico; Massi, Daniela; Lotti, Torello; Pavone, Francesco S.

2011-03-01

229

A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo  

PubMed Central

Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42?nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully. PMID:25640000

Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

2015-01-01

230

A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo.  

PubMed

Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42?nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully. PMID:25640000

Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

2015-01-01

231

Biocatalyst Engineering by Assembly of Fatty Acid Transport and Oxidation Activities for In Vivo Application of Cytochrome P-450BM-3 Monooxygenase  

PubMed Central

The application of whole cells containing cytochrome P-450BM-3 monooxygenase [EC 1.14.14.1] for the bioconversion of long-chain saturated fatty acids to ?-1, ?-2, and ?-3 hydroxy fatty acids was investigated. We utilized pentadecanoic acid and studied its conversion to a mixture of 12-, 13-, and 14-hydroxypentadecanoic acids by this monooxygenase. For this purpose, Escherichia coli recombinants containing plasmid pCYP102 producing the fatty acid monooxygenase cytochrome P-450BM-3 were used. To overcome inefficient uptake of pentadecanoic acid by intact E. coli cells, we made use of a cloned fatty acid uptake system from Pseudomonas oleovorans which, in contrast to the common FadL fatty acid uptake system of E. coli, does not require coupling by FadD (acyl-coenzyme A synthetase) of the imported fatty acid to coenzyme A. This system from P. oleovorans is encoded by a gene carried by plasmid pGEc47, which has been shown to effect facilitated uptake of oleic acid in E. coli W3110 (M. Nieboer, Ph.D. thesis, University of Groningen, Groningen, The Netherlands, 1996). By using a double recombinant of E. coli K27, which is a fadD mutant and therefore unable to consume substrates or products via the ?-oxidation cycle, a twofold increase in productivity was achieved. Applying cytochrome P-450BM-3 monooxygenase as a biocatalyst in whole cells does not require the exogenous addition of the costly cofactor NADPH. In combination with the coenzyme A-independent fatty acid uptake system from P. oleovorans, cytochrome P-450BM-3 recombinants appear to be useful alternatives to the enzymatic approach for the bioconversion of long-chain fatty acids to subterminal hydroxylated fatty acids. PMID:9758800

Schneider, Silke; Wubbolts, Marcel G.; Sanglard, Dominique; Witholt, Bernard

1998-01-01

232

Towards an in vivo wireless mobile robot for surgical assistance.  

PubMed

The use of miniature in vivo robots that fit entirely inside the peritoneal cavity represents a novel approach to laparoscopic surgery. Previous work has demonstrated that mobile and fixed-base in vivo robots can be used to improve visualization of the surgical field and perform surgical tasks such as collecting biopsy tissue samples. All of these robots used tethers to provide for power and data transmission. This paper describes recent work focused on developing a modular wireless mobile platform that could be used for in vivo robotic sensing and manipulation applications. One vision for these types of self-contained in vivo robotic devices is that they could be easily carried and deployed by non-medical personnel at the site of an injury. Such wireless in vivo robots are much more transportable and lower cost than current robotic surgical assistants, and could ultimately allow a surgeon to become a remote first responder irrespective of the location of the patient. PMID:18391277

Hawks, Jeff A; Rentschler, Mark E; Redden, Lee; Infanger, Roger; Dumpert, Jason; Farritor, Shane; Oleynikov, Dmitry; Platt, Stephen R

2008-01-01

233

Rapid multiplexed molecular phenotyping of ex vivo and in vivo tissues with targeted SERS NPs  

NASA Astrophysics Data System (ADS)

We are developing a miniature fiber-optic spectral-detection device and topical-staining protocol to rapidly detect multiplexed surface-enhanced Raman scattering (SERS) nanoparticles (NPs) targeted to cell-surface biomarkers in fresh tissues. Ex vivo and in vivo experiments were performed to optimize our strategy for the rapid detection of multiple cell-surface biomarkers following a brief (5 min) topical application of SERS NPs on tissues. The simultaneous detection and ratiometric quantification of targeted and nontargeted NPs allows for an unambiguous assessment of molecular expression that is insensitive to nonspecific variations in NP concentrations, potentially enabling point-of-care surgical guidance or early disease detection.

Wang, Yu; Khan, Altaz; Som, Madhura; Leigh, Steven Y.; Wang, Danni; Chen, Ye; McVeigh, Patrick; Wilson, Brian C.; Liu, Jonathan T. C.

2014-05-01

234

Mycoplasma biofilms ex vivo and in vivo.  

PubMed

Biofilms are communities of microorganisms that are encased in polymeric matrixes and grow attached to biotic or abiotic surfaces. Despite their enhanced ability to resist antimicrobials and components of the immune system in vitro, few studies have addressed the interactions of biofilms with the host at the organ level. Although mycoplasmas have been shown to form biofilms on glass and plastic surfaces, it has not been determined whether they form biofilms on the tracheal epithelium. We developed a tracheal organ-mounting system that allowed the entire surface of the tracheal lumen to be scanned using fluorescence microscopy. We observed the biofilms formed by the murine respiratory pathogen Mycoplasma pulmonis on the epithelium of trachea in tracheal organ culture and in experimentally infected mice and found similar structure and biological characteristics as biofilms formed in vitro. This tracheal organ-mounting system can be used to study interactions between biofilms formed by respiratory pathogens and the host epithelium and to identify the factors that contribute to biofilm formation in vivo. PMID:19473253

Simmons, Warren L; Dybvig, Kevin

2009-06-01

235

Bi-layer composite dressing of gelatin nanofibrous mat and poly vinyl alcohol hydrogel for drug delivery and wound healing application: in-vitro and in-vivo studies.  

PubMed

Present investigation involves the development of a bi-layer dressing of gelatin nanofibrous mat loaded with epigallocatechin gallate (EGCG)/poly vinyl alcohol (PVA) hydrogel and its in-vivo evaluation on full-thickness excision wounds in experimental Wistar rats. Nanomorphological observation, porosity, effect of crosslinking on tensile strength, physical stability and drug release profile in phosphate buffer and biocompatibility aspects of electrospun nanomat were investigated by various physico-chemical tools. EGCGa release profile was found to increase from 2-4 days with decreasing crosslinking time from 15 to 5 min. PVA hydrogels were prepared by freeze-thaw method and has been utilized as a protective and hydrating outer layer of the bi-layer dressing. Topical application of bi-layer composite dressing loaded with EGCG improve the healing rate in experimental rats as acute wounds model which was evidenced by significant increase in DNA (approximately 42%), total protein (approximately 32%), hydroxyproline (approximately 26%) and hexosamine approximately 24%) contents. A faster wound contraction was observed in wounds treated with composite dressing from approximately 14% to 47%. Histopathological examination revealed significant improvement in angiogenesis, re-epithelialization and less inflammatory response in comparison to control. Van-Gieson's collagen stains revealed matured, compact and parallel deposition of collagen fibrils on day 12. These results were supported by up-regulated expressions of matrix metalloproteinase (MMPs-2 and 9) by gelatin zymography. Control release of EGCG, 3D porous architecture of nanofibrous scaffolds as well as moist microenvironment provides ideal conditions for uninterrupted wound healing. PMID:23980498

Jaiswal, Maneesh; Gupta, Asheesh; Agrawal, Ashwini K; Jassal, Manjeet; Dinda, Amit Kr; Koul, Veena

2013-09-01

236

In vivo Noninvasive Small Animal Molecular Imaging  

PubMed Central

The remarkable efforts that are made on molecular imaging technologies demonstrate its potential importance and range of applications. The generation of disease-specific animal models, and the developments of target-specific probes and genetically encoded reporters are another important component. Continued improvements in the instrumentation, the identification of novel targets and genes, and the availability of improved imaging probes should be made. Multimodal imaging probes should provide easier transitions between laboratory studies, including small animal studies and clinical applications. Here, we reviewed basic strategies of noninvasive in vivo imaging methods in small animals to introducing the concept of molecular imaging. PMID:24159487

Youn, Hyewon; Hong, Kee-Jong

2012-01-01

237

Light dosimetry in vivo  

NASA Astrophysics Data System (ADS)

This paper starts with definitions of radiance, fluence (rate) and other quantities that are important with regard to in vivo light dosimetry. The light distribution in mammalian tissues can be estimated from model calculations using measured optical properties or from direct measurements of fluence rate using a suitable detector. A historical introduction is therefore followed by a brief discussion of tissue optical properties and of calculations using diffusion theory, the -approximation or Monte Carlo simulations. In particular the form of the scattering function is considered in relation to the fluence rate close to the tissue boundary, where light is incident. Non-invasive measurements of optical properties yield the absorption coefficient and , where is the scattering coefficient and g is the mean cosine of the scattering angle. An important question is whether this combination is sufficient, or whether g itself must be known. It appears that for strongly forward scattering, as in mammalian tissues, rather detailed knowledge of the scattering function is needed to reliably calculate the fluence rate close to the surface. Deeper in the tissue is sufficient. The construction, calibration and use of fibre-optic probes for measurements of fluence rate in tissues or optical phantoms is discussed. At present, minimally invasive absolute fluence (rate) measurements seem to be possible with an accuracy of 10 - 20%. Examples are given of in vivo measurements in animal experiments and in humans during clinical treatments. Measurements in mammalian tissues, plant leaves and marine sediments are compared and similarities and differences pointed out. Most in vivo light fluence rate measurements have been concerned with photodynamic therapy (PDT). Optical properties of the same normal tissue may differ between patients. Tumours of the same histological type may even show different optical properties in a single patient. Treatment-induced changes of optical properties may also occur. Scattered light appears to contribute substantially to the light dose. All these phenomena emphasize the importance of in situ light measurements. Another important dosimetric parameter in PDT is the concentration and distribution of the photosensitizer. Apart from in vivo fluorescence monitoring, the photosensitizer part of in vivo PDT dosimetry is still in its infancy.

Star, Willem M.

1997-05-01

238

Electrodeposition of platinum-iridium coatings and nanowires for neurostimulating applications: Fabrication, characterization and in-vivo retinal stimulation/recording. EIS studies of hexavalent and trivalent chromium based military coating systems  

NASA Astrophysics Data System (ADS)

The studies presented in this thesis are composed of two different projects demonstrated in two different parts. The first part of this thesis represents an electrochemical approach to possible improvements of the interface between an implantable device and biological tissue. The second part of this thesis represents electrochemical impedance spectroscopy (EIS) studies on the corrosion resistance behavior of different types of polymer coated Al2024 alloys. In the first part of this thesis, a broad range of investigations on the development of an efficient and reproducible electrochemical deposition method for fabrication of thin-film platinum-iridium alloys were performed. The developed method for production of dense films was then modified to produce very high surface area coatings with ultra-low electrochemical impedance characteristics. The high-surface area platinum-iridium coating was applied on microelectrode arrays for chronic in-vitro stimulation. Using the same method of producing dense films, platinum-iridium nanowires were fabricated using Anodized Aluminum Oxide (AAO) templates for hermetic packaging applications to be used in implantable microelectronics. The implantable microelectronics will be used to perform data reception and transmission management, power recovery, digital processing and analog output of stimulus current. Finally, in-vivo electrical stimulation tests were performed on an animal retina using high surface-area platinum-iridium coated single microelectrodes to verify the charge transfer characteristics of the coatings. In the second part of this thesis, three different sets of samples with different combinations of pretreatments, primers with the same type of topcoat were tested in 0.5 N NaCl for period of 30 days. The surface changes measured by EIS as a function of time were then analyzed. The analysis of the fit parameters of the impedance spectra showed that the different primers had the most effect on the corrosion protection properties of the coatings in which the primers with hexavalent chromium ions (Cr6+) provided better corrosion protection compared to primers with trivalent chromium ions (Cr3+). After 30 days of the exposure of the samples in 0.5 N NaCl, one sample from each set of samples was scribed and exposed to 0.5 N NaCl for 3 days. Analysis of the impedance spectra revealed that the samples with chromium conversion coating pretreatment and hexavalent chromium primer showed "self healing" characteristics and provided better corrosion protection on the scribed areas compared to the scribed samples with trivalent chromium pretreatment and non-hexavalent chromium primer.

Petrossians, Artin

239

A method to study in vivo stability of DNA nanostructures?  

PubMed Central

DNA nanostructures are rationally designed, synthetic, nanoscale assemblies obtained from one or more DNA sequences by their self-assembly. Due to the molecularly programmable as well as modular nature of DNA, such designer DNA architectures have great potential for in cellulo and in vivo applications. However, demonstrations of functionality in living systems necessitates a method to assess the in vivo stability of the relevant nanostructures. Here, we outline a method to quantitatively assay the stability and lifetime of various DNA nanostructures in vivo. This exploits the property of intact DNA nanostructures being uptaken by the coelomocytes of the multicellular model organism Caenorhabditis elegans. These studies reveal that the present fluorescence based assay in coelomocytes of C. elegans is an useful in vivo test bed for measuring DNA nanostructure stability. PMID:23623822

Surana, Sunaina; Bhatia, Dhiraj; Krishnan, Yamuna

2013-01-01

240

Therapeutic face of RNAi: in vivo challenges.  

PubMed

Introduction: RNA interference is a sequence-specific gene silencing phenomenon in which small interfering RNAs (siRNAs) can trigger gene transcriptional and post-transcriptional silencing. This phenomenon represents an emerging therapeutic approach for in vivo studies by efficient delivery of specific synthetic siRNAs against diseases. Therefore, simultaneous development of synthetic siRNAs along with novel delivery techniques is considered as novel and interesting therapeutic challenges. Areas covered: This review provides a basic explanation to siRNA signaling pathways and their therapeutic challenges. Here, we provide a comprehensive explanation to failed and successful trials and their in vivo challenges. Expert opinion: Specific, efficient and targeted delivery of siRNAs is the major concern for their in vivo administrations. Also, anatomical barriers, drug stability and availability, immunoreactivity and existence of various delivery routes, different genetic backgrounds are major clinical challenges. However, successful administration of siRNA-based drugs is expected during foreseeable features. But, their systemic applications will depend on strong targeted drug delivery strategies. PMID:25399911

Borna, Hojat; Imani, Saber; Iman, Maryam; Azimzadeh Jamalkandi, Sadegh

2014-11-15

241

Type I cell ROS kinetics under hypoxia in the intact mouse carotid body ex vivo: a FRET-based study.  

PubMed

Reactive oxygen species (ROS) mainly originating from NADPH oxidases have been shown to be involved in the carotid body (CB) oxygen-sensing cascade. For measuring ROS kinetics, type I cells of the mouse CB in an ex vivo preparation were transfected with the ROS sensor construct FRET-HSP33. After 2 days of tissue culture, type I cells expressed FRET-HSP33 as shown by immunohistochemistry. In one population of CBs, 5 min of hypoxia induced a significant and reversible decrease of type I cell ROS levels (n = 9 CBs; P < 0.015), which could be inhibited by 4-(2-aminoethyl)benzensulfonylfluorid (AEBSF), a highly specific inhibitor of the NADPH oxidase subunits p47phox and p67phox. In another population of CBs, however, 5 min of hypoxia induced a significant and reversible increase of ROS levels in type I cells (n = 8 CBs; P < 0.05), which was slightly enhanced by administration of 3 mM AEBSF. These different ROS kinetics seemed to coincide with different mice breeding conditions. Type I cells of both populations showed a typical hypoxia-induced membrane potential (MP) depolarization, which could be inhibited by 3 mM AEBSF. ROS and MP closely followed the hypoxic decrease in CB tissue oxygen as measured with an O2-sensitive dye. We conclude that attenuated p47phox subunit activity of the NADPH oxidase under hypoxia is the physiological trigger for type I cell MP depolarization probably due to ROS decrease, whereas the observed ROS increase has no influence on type I cell MP kinetics under hypoxia. PMID:25318107

Bernardini, A; Brockmeier, U; Metzen, E; Berchner-Pfannschmidt, U; Harde, E; Acker-Palmer, A; Papkovsky, D; Acker, H; Fandrey, J

2015-01-01

242

[In vivo NMR spectroscopy of the liver].  

PubMed

The application of in vivo MR spectroscopy to the study of the liver is currently an expanding field of research. Owing to technical difficulties, the results obtained thus far were mainly those of animal observations. Several nuclei have been considered: hydrogen, phosphorus, carbon or fluorine. This non-traumatic method allows following and quantifying the various metabolic pathways, especially during hepatic diseases. The major metabolic pathways, i.e. neoglycogenesis, glycogenolysis, Krebs' cycle, etc., are studied, as well as their alterations during diseases such as ischemia, diabetes or alcoholism. The development of this promising technique requires the cooperation of various clinical and fundamental disciplines. PMID:2677330

Jehenson, P; Cuenod, C A; Syrota, A

1989-01-01

243

Application  

Cancer.gov

Application To apply, either email, fax, or mail the following information postmarked by December 31, 2008 to the address below: Curriculum Vitae (that includes complete address, street address, telephone, fax and e-mail) or resume; Two (2) letters

244

Cerenkov Luminescence Tomography for In Vivo Radiopharmaceutical Imaging  

PubMed Central

Cerenkov luminescence imaging (CLI) is a cost-effective molecular imaging tool for biomedical applications of radiotracers. The introduction of Cerenkov luminescence tomography (CLT) relative to planar CLI can be compared to the development of X-ray CT based on radiography. With CLT, quantitative and localized analysis of a radiopharmaceutical distribution becomes feasible. In this contribution, a feasibility study of in vivo radiopharmaceutical imaging in heterogeneous medium is presented. Coupled with a multimodal in vivo imaging system, this CLT reconstruction method allows precise anatomical registration of the positron probe in heterogeneous tissues and facilitates the more widespread application of radiotracers. Source distribution inside the small animal is obtained from CLT reconstruction. The experimental results demonstrated that CLT can be employed as an available in vivo tomographic imaging of charged particle emitters in a heterogeneous medium. PMID:21747821

Zhong, Jianghong; Qin, Chenghu; Yang, Xin; Zhu, Shuping; Zhang, Xing; Tian, Jie

2011-01-01

245

Cerenkov luminescence tomography for in vivo radiopharmaceutical imaging.  

PubMed

Cerenkov luminescence imaging (CLI) is a cost-effective molecular imaging tool for biomedical applications of radiotracers. The introduction of Cerenkov luminescence tomography (CLT) relative to planar CLI can be compared to the development of X-ray CT based on radiography. With CLT, quantitative and localized analysis of a radiopharmaceutical distribution becomes feasible. In this contribution, a feasibility study of in vivo radiopharmaceutical imaging in heterogeneous medium is presented. Coupled with a multimodal in vivo imaging system, this CLT reconstruction method allows precise anatomical registration of the positron probe in heterogeneous tissues and facilitates the more widespread application of radiotracers. Source distribution inside the small animal is obtained from CLT reconstruction. The experimental results demonstrated that CLT can be employed as an available in vivo tomographic imaging of charged particle emitters in a heterogeneous medium. PMID:21747821

Zhong, Jianghong; Qin, Chenghu; Yang, Xin; Zhu, Shuping; Zhang, Xing; Tian, Jie

2011-01-01

246

Nanocrystal targeting in vivo  

NASA Astrophysics Data System (ADS)

Inorganic nanostructures that interface with biological systems have recently attracted widespread interest in biology and medicine. Nanoparticles are thought to have potential as novel intravascular probes for both diagnostic (e.g., imaging) and therapeutic purposes (e.g., drug delivery). Critical issues for successful nanoparticle delivery include the ability to target specific tissues and cell types and escape from the biological particulate filter known as the reticuloendothelial system. We set out to explore the feasibility of in vivo targeting by using semiconductor quantum dots (qdots). Qdots are small (<10 nm) inorganic nanocrystals that possess unique luminescent properties; their fluorescence emission is stable and tuned by varying the particle size or composition. We show that ZnS-capped CdSe qdots coated with a lung-targeting peptide accumulate in the lungs of mice after i.v. injection, whereas two other peptides specifically direct qdots to blood vessels or lymphatic vessels in tumors. We also show that adding polyethylene glycol to the qdot coating prevents nonselective accumulation of qdots in reticuloendothelial tissues. These results encourage the construction of more complex nanostructures with capabilities such as disease sensing and drug delivery.

Åkerman, Maria E.; Chan, Warren C. W.; Laakkonen, Pirjo; Bhatia, Sangeeta N.; Ruoslahti, Erkki

2002-10-01

247

Split GFP IN VIVO Not 4 Profit BMTA LANL Agreement Number: LOS ALAMOS NATIONAL SECURITY, LLC  

E-print Network

Split GFP IN VIVO Not 4 Profit BMTA LANL Agreement Number: LOS ALAMOS NATIONAL SECURITY, LLC/25/07 1 Print Form #12;Split GFP IN VIVO Not 4 Profit BMTA LANL Agreement Number: U.S. Application Serial of the PROVIDER and is made available as a service to the research community and will be used for teaching or not-for-profit

248

Development and Application of a dapB-Based In Vivo Expression Technology System To Study Colonization of Rice by the Endophytic Nitrogen-Fixing Bacterium Pseudomonas stutzeri A15  

Microsoft Academic Search

Pseudomonas stutzeri A15 is a nitrogen-fixing bacterium isolated from paddy rice. Strain A15 is able to colonize and infect rice roots. This strain may provide rice plants with fixed nitrogen and hence promote plant growth. In this article, we describe the use of dapB-based in vivo expression technology to identify P. stutzeri A15 genes that are specifically induced during colonization

Hans Rediers; Victoria Bonnecarrere; Paul B. Rainey; Kelly Hamonts; J. Vanderleyden; R. De Mot

2003-01-01

249

Multicontrast photoacoustic in vivo imaging using near-infrared fluorescent  

E-print Network

Multicontrast photoacoustic in vivo imaging using near-infrared fluorescent proteins Arie Krumholz1 the application of two spectrally distinct near-infrared fluorescent proteins, iRFP670 and iRFP720, engineered-tissue PAT, probes absorbing in the near-infrared (NIR) spectral range are desirable. In the NIR optical

Verkhusha, Vladislav V.

250

In vivo burn imaging using Mueller optical coherence tomography  

E-print Network

-based Mueller-matrix optical coherence tomography system with continuous source-polarization modulation-sensitive Mueller- matrix optical coherence tomography and application in burn imaging," Appl. Opt. 42, 5191In vivo burn imaging using Mueller optical coherence tomography Milos Todorovi, 1,2 Shuliang Jiao

Wang, Lihong

251

Recommendations for conducting the in vivo alkaline Comet assay  

Microsoft Academic Search

The in vivo alkaline single cell gel electrophoresis assay, hereafter the Comet assay, can be used to investigate the genotoxicity of industrial chemicals, biocides, agrochem- icals and pharmaceuticals. The major advantages of this assay include the relative ease of application to any tissue of interest, the detection of multiple classes of DNA damage and the generation of data at the

A. Hartmann; E. Agurell; C. Beevers; S. Brendler-Schwaab; B. Burlinson; P. Clay; A. Collins; A. Smith; G. Speit; V. Thybaud; R. R. Tice

2003-01-01

252

Programmable nanoparticle functionalization for in vivo targeting  

PubMed Central

The emerging demand for programmable functionalization of existing base nanocarriers necessitates development of an efficient approach for cargo loading that avoids nanoparticle redesign for each individual application. Herein, we demonstrate in vivo a postformulation strategy for lipidic nanocarrier functionalization with the use of a linker peptide, which rapidly and stably integrates cargos into lipidic membranes of nanocarriers after simple mixing through a self-assembling process. We exemplified this strategy by generating a VCAM-1-targeted perfluorocarbon nanoparticle for in vivo targeting in atherosclerosis (ApoE-deficient) and breast cancer (STAT-1-deficient) models. In the atherosclerotic model, a 4.1-fold augmentation in binding to affected aortas was observed for targeted vs. nontargeted nanoparticles (P<0.0298). Likewise, in the breast cancer model, a 4.9-fold increase in the nanoparticle signal from tumor vasculature was observed for targeted vs. nontargeted nanoparticles (P<0.0216). In each case, the nanoparticle was registered with fluorine (19F) magnetic resonance spectroscopy of the nanoparticle perfluorocarbon core, yielding a quantitative estimate of the number of tissue-bound nanoparticles. Because other common nanocarriers with lipid coatings (e.g., liposomes, micelles, etc.) can employ this strategy, this peptide linker postformulation approach is applicable to more than half of the available nanosystems currently in clinical trials or clinical uses.—Pan, H., Myerson, J. W., Hu, L., Marsh, J. N., Hou K., Scott, M. J., Allen, J. S., Hu, G., San Roman, S., Lanza, G. M., Schreiber, R. D., Schlesinger, P. H., Wickline, S. A. Programmable nanoparticle functionalization for in vivo targeting. PMID:23047896

Pan, Hua; Myerson, Jacob W.; Hu, Lingzhi; Marsh, Jon N.; Hou, Kirk; Scott, Michael J.; Allen, John S.; Hu, Grace; San Roman, Susana; Lanza, Gregory M.; Schreiber, Robert D.; Schlesinger, Paul H.; Wickline, Samuel A.

2013-01-01

253

Split GFP Foreign IN VIVO Not 4 Profit BMTA LANL Agreement Number: LOS ALAMOS NATIONAL SECURITY, LLC  

E-print Network

Split GFP Foreign IN VIVO Not 4 Profit BMTA LANL Agreement Number: LOS ALAMOS NATIONAL SECURITY/13087; and associated priority application(s). Rev. 6/25/07 1 Print Form #12;Split GFP Foreign IN VIVO Not 4 Profit BMTA and will be used for teaching or not-for-profit research purposes only. The RECIPIENT does not acquire any property

254

Development of a low SWaP laser transmitter for atmospheric lidar applications  

NASA Astrophysics Data System (ADS)

NASA Langley Research Center (LaRC) is working on a prototype laser system for simultaneous measurement of CO2 and O2 for planned Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission application. For this purpose, 1571 nm spectral band for CO2 sensing and 1262 nm spectral band for oxygen sensing have been selected. In this paper, we discuss recent progress made in the development of single mode, compact and stable, seed laser technologies for CO2 and O2 transmitters. In particular, the development of an advanced distributed feedback laser (DFB) module master oscillator operating at 1571 nm, that is efficiently coupled to drive electronics and nano-cooling scheme in a single hermetically sealed package of volume less than 2" x 2" x 0.5", is presented.

Prasad, Narasimha S.; Rosiewicz, Alex; Coleman, Steven M.

2011-02-01

255

Application  

Microsoft Academic Search

\\u000a This chapter serves two major purposes. First of all it outlines general usage domains for the enMedia framework that has\\u000a been presented in this book. The second purpose is to demonstrate in detail the application of the enMedia framework and its\\u000a prototype implementation, SilkRoad, through a sequence of electronic negotiation scenario cases. In these cases, specific emphasis is set on

Michael Ströbel

256

Photoacoustic Tomography of a Rat Cerebral Cortex in vivo with Au  

E-print Network

be better suited for in vivo applications. We sequentially injected Au nanocages into the circulatory system to dysfunctional anatomi- cal conditions such as localized leaky circulatory and lymphatic systems. This feature

Wang, Lihong

257

Progress Toward In Vivo Use of siRNAs-II  

PubMed Central

RNA interference (RNAi) has been extensively employed for in vivo research since its use was first demonstrated in mammalian cells 10 years ago. Design rules have improved, and it is now routinely possible to obtain reagents that suppress expression of any gene desired. At the same time, increased understanding of the molecular basis of unwanted side effects has led to the development of chemical modification strategies that mitigate these concerns. Delivery remains the single greatest hurdle to widespread adoption of in vivo RNAi methods. However, exciting advances have been made and new delivery systems under development may help to overcome these barriers. This review discusses advances in RNAi biochemistry and biology that impact in vivo use and provides an overview of select publications that demonstrate interesting applications of these principles. Emphasis is placed on work with synthetic, small interfering RNAs (siRNAs) published since the first installment of this review which appeared in 2006. PMID:22186795

Rettig, Garrett R; Behlke, Mark A

2012-01-01

258

In vivo imaging of elastic fibers using sulforhodamine B.  

PubMed

Until now, the imaging of elastic fibers was restricted to tissue sections using the endofluorescence properties of elastin or histological dyes. Methods to study their morphology in vivo and in situ have been lacking. We present and characterize a new application of a fluorescent dye for two-photon microscopy: sulforhodamine B (SRB), which is shown to specifically stain elastic fibers in vivo. SRB staining of elastic fibers is demonstrated to be better than using elastin endofluorescence for two-photon microscopy. Our imaging method of elastic fibers is shown to be suitable for simultaneous imaging with both other fluorescent intravital dyes and second-harmonic generation (SHG). We illustrate these findings with intravital imaging of elastic and collagen fibers in muscle epimysium and endomysium and in blood vessel walls. We expect SRB staining to become a key method to study elastic fibers in vivo. PMID:18163833

Ricard, Clément; Vial, Jean-Claude; Douady, Julien; van der Sanden, Boudewijn

2007-01-01

259

In vivo Raman spectroscopy of cervix cancers  

NASA Astrophysics Data System (ADS)

Cervix-cancer is the third most common female cancer worldwide. It is the leading cancer among Indian females with more than million new diagnosed cases and 50% mortality, annually. The high mortality rates can be attributed to late diagnosis. Efficacy of Raman spectroscopy in classification of normal and pathological conditions in cervix cancers on diverse populations has already been demonstrated. Our earlier ex vivo studies have shown the feasibility of classifying normal and cancer cervix tissues as well as responders/non-responders to Concurrent chemoradiotherapy (CCRT). The present study was carried out to explore feasibility of in vivo Raman spectroscopic methods in classifying normal and cancerous conditions in Indian population. A total of 182 normal and 132 tumor in vivo Raman spectra, from 63 subjects, were recorded using a fiberoptic probe coupled HE-785 spectrometer, under clinical supervision. Spectra were acquired for 5 s and averaged over 3 times at 80 mW laser power. Spectra of normal conditions suggest strong collagenous features and abundance of non-collagenous proteins and DNA in case of tumors. Preprocessed spectra were subjected to Principal Component-Linear Discrimination Analysis (PCLDA) followed by leave-one-out-cross-validation. Classification efficiency of ~96.7% and 100% for normal and cancerous conditions respectively, were observed. Findings of the study corroborates earlier studies and suggest applicability of Raman spectroscopic methods in combination with appropriate multivariate tool for objective, noninvasive and rapid diagnosis of cervical cancers in Indian population. In view of encouraging results, extensive validation studies will be undertaken to confirm the findings.

Rubina, S.; Sathe, Priyanka; Dora, Tapas Kumar; Chopra, Supriya; Maheshwari, Amita; Krishna, C. Murali

2014-03-01

260

In-vivo morphologic and spectroscopic investigation of Psoriasis  

NASA Astrophysics Data System (ADS)

Psoriasis is an autoimmune disease of the skin characterized by hyperkeratosis, hyperproliferation of the epidermis, inflammatory cell accumulation and increased dilatation of dermal papillary blood vessels. Cases of psoriasis were investigated in vivo with optical means in order to evaluate the potential of in vivo optical biopsy. A Polarization Multispectral Dermoscope was employed for the macroscopic observation. Features such as the 'dotted' blood vessels pattern was observed with high contrast. High resolution image sections of the epidermis and the dermis were produced with a custom made Multiphoton Microscope. Imaging extended from the surface of the lesion down to the papillary dermis, at a depth of 200 ?m. In the epidermis, a characteristic morphology of the stratum corneum found only in Psoriasis was revealed. Additionally, the cytoplasmic area of the cells in the stratum spinosum layer was found to be smaller than normal. In the dermis the morphological features were more pronounced, where the elongated dermal papillae dominated the papillary layer. Their length exceeds 100?m, which is a far greater value compared to that of healthy skin. These in vivo observations are consistent with the ex vivo histopathological observations, supporting both the applicability and potentiality of multispectral dermoscopy and multiphoton microscopy in the field of in vivo optical investigation and biopsy of skin.

Kapsokalyvas, Dimitrios; Cicchi, Riccardo; Bruscino, Nicola; Alfieri, Domenico; Massi, Daniela; Lotti, Torello; Pavone, Francesco S.

2011-07-01

261

Experimental Cryosurgery Investigations In Vivo  

PubMed Central

Cryosurgery is the use of freezing temperatures to elicit an ablative response in a targeted tissue. This review provides a global overview of experimentation in vivo which has been the basis of advancement of this widely applied therapeutic option. The cellular and tissue-related events that underlie the mechanisms of destruction, including direct cell injury (cryolysis), vascular stasis, apoptosis and necrosis, are described and are related to the optimal methods of technique of freezing to achieve efficacious therapy. In vivo experiments with major organs, including wound healing, the putative immunological response following thawing, and the use of cryoadjunctive strategies to enhance cancer cell sensitivity to freezing, are described. PMID:19833119

Gage, A.A.; Baust, J.M.; Baust, J.G.

2009-01-01

262

The in vivo activation of persistent nanophosphors for optical imaging of vascularization, tumours and grafted cells  

NASA Astrophysics Data System (ADS)

Optical imaging for biological applications requires more sensitive tools. Near-infrared persistent luminescence nanoparticles enable highly sensitive in vivo optical detection and complete avoidance of tissue autofluorescence. However, the actual generation of persistent luminescence nanoparticles necessitates ex vivo activation before systemic administration, which prevents long-term imaging in living animals. Here, we introduce a new generation of optical nanoprobes, based on chromium-doped zinc gallate, whose persistent luminescence can be activated in vivo through living tissues using highly penetrating low-energy red photons. Surface functionalization of this photonic probe can be adjusted to favour multiple biomedical applications such as tumour targeting. Notably, we show that cells can endocytose these nanoparticles in vitro and that, after intravenous injection, we can track labelled cells in vivo and follow their biodistribution by a simple whole animal optical detection, opening new perspectives for cell therapy research and for a variety of diagnosis applications.

Maldiney, Thomas; Bessière, Aurélie; Seguin, Johanne; Teston, Eliott; Sharma, Suchinder K.; Viana, Bruno; Bos, Adrie J. J.; Dorenbos, Pieter; Bessodes, Michel; Gourier, Didier; Scherman, Daniel; Richard, Cyrille

2014-04-01

263

Development and Application of a dapB-Based In Vivo Expression Technology System To Study Colonization of Rice by the Endophytic Nitrogen-Fixing Bacterium Pseudomonas stutzeri A15  

PubMed Central

Pseudomonas stutzeri A15 is a nitrogen-fixing bacterium isolated from paddy rice. Strain A15 is able to colonize and infect rice roots. This strain may provide rice plants with fixed nitrogen and hence promote plant growth. In this article, we describe the use of dapB-based in vivo expression technology to identify P. stutzeri A15 genes that are specifically induced during colonization and infection (cii). We focused on the identification of P. stutzeri A15 genes that are switched on during rice root colonization and are switched off during free-living growth on synthetic medium. Several transcriptional fusions induced in the rice rhizosphere were isolated. Some of the corresponding genes are involved in the stress response, chemotaxis, metabolism, and global regulation, while others encode putative proteins with unknown functions or without significant homology to known proteins. PMID:14602651

Rediers, Hans; Bonnecarrère, Victoria; Rainey, Paul B.; Hamonts, Kelly; Vanderleyden, Jos; De Mot, René

2003-01-01

264

Non-Invasive in vivo Mapping and Long-Term Monitoring of Magnetic Nanoparticles in Different Organs of Animals  

NASA Astrophysics Data System (ADS)

Quantitative detection of magnetic nanoparticles (MP) in vivo is very important for various biomedical applications. Our original detection method based on non-linear MP magnetization has been modified for non-invasive in vivo mapping of the MP distribution among different organs of rats. A novel highly sensitive room-temperature device equipped with an external probe has been designed and tested for quantification of MP within 20-mm depth from the animal skin. Results obtained by external in vivo scanning of rats by the probe and ex vivo MP quantification in different organs of rats well correlated. The method allows long-term in vivo study of MP evolution, clearance and redistribution among different organs of the animal. Experiments showed that dynamics in vivo strongly depend on MP characteristics (size, material, coatings, etc.), site of injection and dose. The developed detection method combined with the magnetic nanolabels can substitute the radioactive labeling in many applications.

Nikitin, Maxim; Yuriev, Mikhail; Brusentsov, Nikolai; Vetoshko, Petr; Nikitin, Petr

2010-12-01

265

Respiratory Rhythm Generation In Vivo  

PubMed Central

The cellular and circuit mechanisms generating the rhythm of breathing in mammals have been under intense investigation for decades. Here, we try to integrate the key discoveries into an updated description of the basic neural processes generating respiratory rhythm under in vivo conditions. PMID:24382872

Richter, Diethelm W.; Smith, Jeffrey C.

2014-01-01

266

In aqua vivo EPID dosimetry  

SciTech Connect

Purpose: At the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital in vivo dosimetry using an electronic portal imaging device (EPID) has been implemented for almost all high-energy photon treatments of cancer with curative intent. Lung cancer treatments were initially excluded, because the original back-projection dose-reconstruction algorithm uses water-based scatter-correction kernels and therefore does not account for tissue inhomogeneities accurately. The aim of this study was to test a new method, in aqua vivo EPID dosimetry, for fast dose verification of lung cancer irradiations during actual patient treatment. Methods: The key feature of our method is the dose reconstruction in the patient from EPID images, obtained during the actual treatment, whereby the images have been converted to a situation as if the patient consisted entirely of water; hence, the method is termed in aqua vivo. This is done by multiplying the measured in vivo EPID image with the ratio of two digitally reconstructed transmission images for the unit-density and inhomogeneous tissue situation. For dose verification, a comparison is made with the calculated dose distribution with the inhomogeneity correction switched off. IMRT treatment verification is performed for each beam in 2D using a 2D {gamma} evaluation, while for the verification of volumetric-modulated arc therapy (VMAT) treatments in 3D a 3D {gamma} evaluation is applied using the same parameters (3%, 3 mm). The method was tested using two inhomogeneous phantoms simulating a tumor in lung and measuring its sensitivity for patient positioning errors. Subsequently five IMRT and five VMAT clinical lung cancer treatments were investigated, using both the conventional back-projection algorithm and the in aqua vivo method. The verification results of the in aqua vivo method were statistically analyzed for 751 lung cancer patients treated with IMRT and 50 lung cancer patients treated with VMAT. Results: The improvements by applying the in aqua vivo approach are considerable. The percentage of {gamma} values {<=}1 increased on average from 66.2% to 93.1% and from 43.6% to 97.5% for the IMRT and VMAT cases, respectively. The corresponding mean {gamma} value decreased from 0.99 to 0.43 for the IMRT cases and from 1.71 to 0.40 for the VMAT cases, which is similar to the accepted clinical values for the verification of IMRT treatments of prostate, rectum, and head-and-neck cancers. The deviation between the reconstructed and planned dose at the isocenter diminished on average from 5.3% to 0.5% for the VMAT patients and was almost the same, within 1%, for the IMRT cases. The in aqua vivo verification results for IMRT and VMAT treatments of a large group of patients had a mean {gamma} of approximately 0.5, a percentage of {gamma} values {<=}1 larger than 89%, and a difference of the isocenter dose value less than 1%. Conclusions: With the in aqua vivo approach for the verification of lung cancer treatments (IMRT and VMAT), we can achieve results with the same accuracy as obtained during in vivo EPID dosimetry of sites without large inhomogeneities.

Wendling, Markus; McDermott, Leah N.; Mans, Anton; Olaciregui-Ruiz, Igor; Pecharroman-Gallego, Raul; Sonke, Jan-Jakob; Stroom, Joep; Herk, Marcel J.; Mijnheer, Ben van [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)

2012-01-15

267

In vivo nanotoxicity assays in plant models.  

PubMed

Increasing application of silver nanoparticles (SNPs) and zinc oxide nanoparticles (nZnO) in consumer products like textiles, cosmetics, washing machines and other household products increases their chance to reach the environment. Intensive research is required to assess the nanoparticles' toxicity to the environmental system. The toxicological effect of nanoparticles has been studied at the miniscule scale and requires intensive research to be conducted to assess its unknown effects. Plants are the primary target species which need to be included to develop a comprehensive toxicity profile for nanoparticles. So far, the mechanisms of toxicity of nanoparticles to the plant system remains largely unknown and little information on the potential uptake of nanoparticles by plants and their subsequent fate within the food chain is available. The phytoxicological behaviour of silver and zinc oxide nanoparticles on Allium cepa and seeds of Zea mays (maize), Cucumis sativus (cucumber) and Lycopersicum esculentum (tomato) was done. The in vitro studies on A. cepa have been done to check the cytotoxicological effects including mitotic index, chromosomal aberrations, vagrant chromosomes, sticky chromosomes, disturbed metaphase, breaks and formation of micronucleus. In vitro and in vivo studies on seed systems exposed to different concentration of nanoparticles dispersion to check phytotoxicity end point as root length, germination effect, adsorption and accumulation of nanoparticles (uptake studies) into the plant systems. In vivo studies in a seed system was done using phytagel medium. Biochemical studies were done to check effect on protein, DNA and thiobarbituric acid reactive species concentration. FT-IR studies were done to analyze the functional and conformational changes in the treated and untreated samples. The toxicological effects of nanoparticles had to be studied at the miniscule scale to address existing environment problems or prevent future problems. The findings suggest that the engineered nanoparticles, though having significant advantages in research and medical applications, requires a great deal of toxicity database to ascertain the biosafety and risk of using engineered nanoparticles in consumer products. PMID:22975978

Kumari, Mamta; Ernest, Vinita; Mukherjee, Amitava; Chandrasekaran, Natarajan

2012-01-01

268

3D ultrafast ultrasound imaging in vivo  

NASA Astrophysics Data System (ADS)

Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32? × ?32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.

Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

2014-10-01

269

3D ultrafast ultrasound imaging in vivo.  

PubMed

Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32? × ?32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability. PMID:25207828

Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

2014-10-01

270

In vivo imaging of Drosophila melanogaster  

E-print Network

-expressing salivary glands and wing imaginal discs in living Drosophila melanogaster pupae in vivo and over timeIn vivo imaging of Drosophila melanogaster pupae with mesoscopic fluorescence tomography Claudio

Perrimon, Norbert

271

Near-infrared Molecular Probes for In Vivo Imaging  

PubMed Central

Cellular and tissue imaging in the near-infrared (NIR) wavelengths between 700 and 900 nm is advantageous for in vivo because of the low absorption of biological molecules in this region. This Unit presents protocols for small animal imaging using planar and fluorescence lifetime imaging techniques. Included is an overview of NIR fluorescence imaging of cells and small animals using NIR organic fluorophores, nanoparticles, and multimodal imaging probes. The development, advantages, and application of NIR fluorescent probes that have been used for in vivo imaging are also summarized. The use of NIR agents in conjunction with visible dyes and considerations in selecting imaging agents are discussed. We conclude with practical considerations for the use of these dyes in cell and small animal imaging applications. PMID:22470154

Zhang, Xuan; Bloch, Sharon; Akers, Walter; Achilefu, Samuel

2012-01-01

272

19F MRI for quantitative in vivo cell tracking  

PubMed Central

Cellular therapy, including stem cell transplants and dendritic cell vaccines, is typically monitored for dosage optimization, accurate delivery and localization using non-invasive imaging, of which magnetic resonance imaging (MRI) is a key modality. 19F MRI retains the advantages of MRI as an imaging modality, while allowing direct detection of labelled cells for unambiguous identification and quantification, unlike typical metal-based contrast agents. Recent developments in 19F MRI-based in vivo cell quantification, the existing clinical use of 19F compounds and current explosive interest in cellular therapeutics have brought 19F imaging technology closer to clinical application. We review the application of 19F MRI to cell tracking, discussing intracellular 19F labels, cell labelling and in vivo quantification, as well as the potential clinical use of 19F MRI. PMID:20427096

Srinivas, Mangala; Heerschap, Arend; Ahrens, Eric T.; Figdor, Carl G.; de Vries, I. Jolanda M.

2010-01-01

273

Rapid and simultaneous measurement of midazolam, 1'-hydroxymidazolam and digoxin by liquid chromatography/tandem mass spectrometry: application to an in vivo study to simultaneously measure P-glycoprotein and cytochrome P450 3A activity.  

PubMed

In order to simultaneously determine in vivo P-glycoprotein (P-gp) and Cytochrome P450 3A (CYP3A) activity, a new, rapid and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been developed and fully validated to simultaneously determine midazolam (MDZ, as CYP3A substrate), 1'-hydroxymidazolam (1'-OHMDZ) and digoxin (DG, as P-gp substrate) in rat plasma using digitoxin as the internal standard (IS). After a single step liquid-liquid extraction with tert-butyl methyl ether/dichloromethane (75:25, v/v), analytes were subjected to LC-MS/MS analysis using positive electro-spray ionization (ESI(+)) under selected reaction monitoring mode (SRM). Chromatographic separation was performed on an XTerra MS C18 column (50mm×2.1mm, i.d. 3.5?m). The MS/MS detection was conducted by monitoring the fragmentation of 326.05 ? 244.00 (m/z) for MDZ, 342.02 ?168.01 (m/z) for 1'-OHMDZ, 798.33 ? 651.36(m/z) for DG and 782.67 ? 635.24 (m/z) for IS. The method had a chromatographic running time of 3min and linear calibration curves over the concentrations of 2-400ng/mL for MDZ and 1'-OHMDZ and 0.5-100ng/mL for DG. The recoveries of the method were 86.8-96.3% for MDZ, 84.6-86.4% for 1'-OH MDZ, and 81.7-85.1% for DG. The lower limit of quantification (LLOQ) of the method was 2ng/mL for MDZ and 1'-OHMDZ and 0.5ng/mL for DG. The intra- and inter-batch precision were less than 15% for all quality control samples at concentrations of 5, 50 and 320ng/mL for MDZ and 1'-OHMDZ and 1, 10 and 80ng/mL for DG. The validated LC-MS/MS method has been successfully used to analyze the concentrations of MDZ, 1'-OH MDZ and DG in rat plasma for simultaneous measurement of in vivo P-gp and CYP 3A activity. PMID:21316177

Xue, Xinping; Huang, Min; Xiao, Huanyu; Qin, Xiaoling; Huang, Ling; Zhong, Guoping; Bi, Huichang

2011-04-28

274

Ultra-performance liquid chromatography tandem mass spectrometry method for the determination of AZ66, a sigma receptor ligand, in rat plasma and its application to in vivo pharmacokinetics.  

PubMed

Methamphetamine abuse continues as a major problem in the USA owing to its powerful psychological addictive properties. AZ66, 3-[4-(4-cyclohexylpiperazine-1-yl)pentyl]-6-fluorobenzo[d]thiazole-2(3H)-one, an optimized sigma receptor ligand, is a promising therapeutic agent against methamphetamine. To study the in vivo pharmacokinetics of this novel sigma receptor ligand in rats, a sensitive ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) method was developed in rat plasma and validated. The developed method requires a small volume of plasma (100 ?L) and a simple liquid-liquid extraction. The chromatographic separations were achieved in 3.3 min using an Acquity UPLC BEH Shield RP18 column. The mass spectrophotometric detection was carried out using a Waters Micromass Quattro MicroTM triple-quadrupole system. Multiple reaction monitoring was used for the quantitation with transitions m/z 406 ? m/z 181 for AZ66 and m/z 448 ? m/z 285 for aripiprazole. The method was validated over a concentration range of 1-3500 ng/mL and the lower limit of quantitation was determined to be 1 ng/mL. Validation of the assay demonstrated that the developed UPLC/MS/MS method was sensitive, accurate and selective for the determination of AZ66 in rat plasma. The present method has been successfully applied to an i.v. pharmacokinetic study in Sprague-Dawley rats. PMID:23558564

Jamalapuram, Seshulatha; Vuppala, Pradeep Kumar; Abdelazeem, Ahmed H; McCurdy, Christopher R; Avery, Bonnie A

2013-08-01

275

In Vivo and Ex Vivo Transcutaneous Glucose Detection Using Surface-Enhanced Raman Spectroscopy  

NASA Astrophysics Data System (ADS)

Diabetes mellitus is widely acknowledged as a large and growing health concern. The lack of practical methods for continuously monitoring glucose levels causes significant difficulties in successful diabetes management. Extensive validation work has been carried out using surface-enhanced Raman spectroscopy (SERS) for in vivo glucose sensing. This dissertation details progress made towards a Raman-based glucose sensor for in vivo, transcutaneous glucose detection. The first presented study combines spatially offset Raman spectroscopy (SORS) with SERS (SESORS) to explore the possibility of in vivo, transcutaneous glucose sensing. A SERS-based glucose sensor was implanted subcutaneously in Sprague-Dawley rats. SERS spectra were acquired transcutaneously and analyzed using partial least-squares (PLS). Highly accurate and consistent results were obtained, especially in the hypoglycemic range. Additionally, the sensor demonstrated functionality at least17 days after implantation. A subsequent study further extends the application of SESORS to the possibility of in vivo detection of glucose in brain through skull. Specifically, SERS nanoantennas were buried in an ovine tissue behind a bone with 8 mm thickness and detected by using SESORS. In addition, quantitative detection through bones by using SESORS was also demonstrated. A device that could measure glucose continuously as well as noninvasively would be of great use to patients with diabetes. The inherent limitation of the SESORS approach may prevent this technique from becoming a noninvasive method. Therefore, the prospect of using normal Raman spectroscopy for glucose detection was re-examined. Quantitative detection of glucose and lactate in the clinically relevant range was demonstrated by using normal Raman spectroscopy with low power and short acquisition time. Finally, a nonlinear calibration method called least-squares support vector machine regression (LS-SVR) was investigated for analyzing spectroscopic data sets of glucose detection. Comparison studies were demonstrated between LS-SVR and PLS. LS-SVR demonstrated significant improvements in accuracy over PLS for glucose detection, especially when a global calibration model was required. The improvements imparted by LS-SVR open up the possibility of developing an accurate prediction algorithm for Raman-based glucose sensing applicable to a large human population. Overall, these studies show the high promise held by the Raman-based sensor for the challenge of optimal glycemic control.

Ma, Ke

276

In vivo dosimetry with silicon diodes in total body irradiation  

NASA Astrophysics Data System (ADS)

The aim of this work is the characterization and application of silicon diode detectors for in vivo dosimetry in total body irradiation (TBI) treatments. It was evaluated the diode response with temperature, dose rate, gantry angulations and field size. A maximum response variation of 2.2% was obtained for temperature dependence. The response variation for dose rate and angular was within 1.2%. For field size dependence, the detector response increased with field until reach a saturation region, where no more primary radiation beam contributes for dose. The calibration was performed in a TBI setup. Different lateral thicknesses from one patient were simulated and then the calibration factors were determined by means of maximum depth dose readings. Subsequent to calibration, in vivo dosimetry measurements were performed. The response difference between diode readings and the prescribed dose for all treatments was below 4%. This difference is in agreement as recommended by the International Commission on Radiation Units and Measurements (ICRU), which is ±5%. The present work to test the applicability of a silicon diode dosimetry system for performing in vivo dose measurements in TBI techniques presented good results. These measurements demonstrated the value of diode dosimetry as a treatment verification method and its applicability as a part of a quality assurance program in TBI treatments.

Oliveira, F. F.; Amaral, L. L.; Costa, A. M.; Netto, T. G.

2014-02-01

277

Computacion inteligente con organismos vivos  

E-print Network

resoluci´on. 2 / 37 #12;Computaci´on y M´aquinas ... VIVAS e INTELIGENTES 3 / 37 #12;Modelo de computaci tediosas... ... y otras tareas inteligentes. 7 / 37 #12;M´aquinas de prop´osito espec´ifico Desde el ´abacoComputaci´on inteligente con organismos vivos Mario de Jes´us P´erez Jim´enez Grupo de Investigaci

Jiménez, Mario de J. Pérez

278

Multimodal In Vivo Skin Imaging with Integrated Optical Coherence and Multiphoton Microscopy  

PubMed Central

In this paper, we demonstrate high-resolution, multimodal in vivo imaging of human skin using optical coherence (OCM) and multiphoton microscopy (MPM). These two modalities are integrated into a single instrument to enable simultaneous acquisition and coregistration. The system design and the OCM image processing architecture enable sufficient performance of both modalities for in vivo imaging of human skin. Examples of multimodal in vivo imaging are presented as well as time lapse imaging of blood flow in single capillary loops. By making use of multiple intrinsic contrast mechanisms this integrated technique improves the ability to noninvasively visualize living tissue. Integrated OCM and MPM has potential applications for in vivo diagnosis of various pathological skin conditions, such as skin cancer, as well as potential pharmaceutical and cosmetic research applications.

Graf, Benedikt W.; Boppart, Stephen A.

2014-01-01

279

In vivo MRI cell tracking using perfluorocarbon probes and fluorine-19 detection  

PubMed Central

This article is a brief survey of preclinical in vivo cell tracking methods and applications using perfluorocarbon (PFC) probes and fluorine-19 (19F) MRI detection. Detection of the 19F signal offers high cell specificity and quantification abilities in spin-density weighted MR images. We discuss the compositions of matter, methods, and applications of PFC-based cell tracking using ex vivo and in situ PFC labeling in preclinical studies of inflammation and cellular therapeutics. We will also address potential applicability of 19F cell tracking to clinical trials. PMID:23606473

Ahrens, Eric T.; Zhong, Jia

2013-01-01

280

Wide-field in vivo background free imaging by selective magnetic modulation of nanodiamond fluorescence  

PubMed Central

The sensitivity and resolution of fluorescence-based imaging in vivo is often limited by autofluorescence and other background noise. To overcome these limitations, we have developed a wide-field background-free imaging technique based on magnetic modulation of fluorescent nanodiamond emission. Fluorescent nanodiamonds are bright, photo-stable, biocompatible nanoparticles that are promising probes for a wide range of in vitro and in vivo imaging applications. Our readily applied background-free imaging technique improves the signal-to-background ratio for in vivo imaging up to 100-fold. This technique has the potential to significantly improve and extend fluorescent nanodiamond imaging capabilities on diverse fluorescence imaging platforms. PMID:24761300

Sarkar, Susanta K.; Bumb, Ambika; Wu, Xufeng; Sochacki, Kem A.; Kellman, Peter; Brechbiel, Martin W.; Neuman, Keir C.

2014-01-01

281

Multiphoton polarization imaging of the stratum corneum and the dermis in ex-vivo human skin  

Microsoft Academic Search

In this work, we demonstrate the application of multiphoton polarization imaging in resolving the structures in surface stratum corneum and dermal layers of ex-vivo human skin. By varying the excitation and emission polarizations, we characterized the structural features in both Laurdan labeled stratum corneum and dermal fibers. The results presented here have important consequences in bioimaging applications of the skin.

Yen Sun; Jiunn-Wen Su; Wen Lo; Sun-Jan Lin; Shiou-Hwa Jee; Chen-Yuan Dong

2003-01-01

282

On-chip immobilization of planarians for in vivo imaging  

PubMed Central

Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra. PMID:25227263

Dexter, Joseph P.; Tamme, Mary B.; Lind, Christine H.; Collins, Eva-Maria S.

2014-01-01

283

On-chip immobilization of planarians for in vivo imaging.  

PubMed

Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra. PMID:25227263

Dexter, Joseph P; Tamme, Mary B; Lind, Christine H; Collins, Eva-Maria S

2014-01-01

284

Spatial light modulator based active wide-field illumination for ex vivo and in vivo quantitative NIR FRET imaging  

PubMed Central

Fluorescence lifetime imaging is playing an increasing role in drug development by providing a sensitive method to monitor drug delivery and receptor-ligand interactions. However, the wide dynamic range of fluorescence intensity emitted by ex vivo and in vivo samples presents challenges in retrieving information over the whole subject accurately and quantitatively. To overcome this challenge, we developed an active wide-field illumination (AWFI) strategy based on a spatial light modulator that acquires optimal fluorescence signals by enhancing the dynamic range, signal to noise ratio, and estimation of lifetime-based parameters. We demonstrate the ability of AWFI to estimate Förster resonance energy transfer (FRET) donor fraction from dissected organs with high accuracy (standard deviation <6%) over the whole field of view, in contrast with the homogenous wide-field illumination. We further report its successful application to quantitative FRET imaging in a live mouse. AWFI allows improved detection of weak signals and enhanced quantitative accuracy in ex vivo and in vivo molecular fluorescence quantitative imaging. The technique allows for robust quantitative estimation of the bio-distribution of molecular probes and lifetime-based parameters over an extended imaging field exhibiting a large range of fluorescence intensities and at a high acquisition speed (less than 1 min). PMID:24688826

Zhao, Lingling; Abe, Ken; Rajoria, Shilpi; Pian, Qi; Barroso, Margarida; Intes, Xavier

2014-01-01

285

Design of meloxicam and lornoxicam transdermal patches: Preparation, physical characterization, ex vivo and in vivo studies.  

PubMed

Transdermal patches of meloxicam (MX) and lornoxicam (LX) were aimed to be prepared in order to overcome their side effects by oral application. The strategy was formulation of optimized films to prepare transdermal patches by determination of physical properties and investigation of drug-excipient compatibility. As the next step, in vitro drug release, assesment of anti-inflammatory effect on Wistar Albino rats, ex vivo skin penetration and investigation of factors on drug release from transdermal patches were studied. Hydroxypropyl methylcellulose (HPMC) was concluded to be suitable polymer for formulation of MX and LX transdermal films indicating pharmaceutical quality required. MX and LX transdermal patches gave satisfactory results regarding to the edema inhibition in the assessment of anti-inflammatory effect. MX was found out to be more effective compared to LX on relieving of edema and swelling. These results were supported by data obtained from ex vivo penetration experiments of drug through rat skin. Indicative parameters like log P, molecular weight and solubility constraint on penetration rate of drugs also indicated good skin penetration. Transdermal patches of MX and LX can be suggested to be used especially for the immediate treatment of inflammated area since it displays anti-inflammatory effect, soon. PMID:21048338

Yener, Gülgün; Üner, Melike; Gönüllü, Ümit; Yildirim, Sinem; Kiliç, P?nar; Aslan, Serap Sa?lik; Barla, Asl?

2010-11-01

286

Biophotonics techniques for structural and functional imaging, in vivo  

PubMed Central

In vivo optical imaging is being conducted in a variety of medical applications, including optical breast cancer imaging, functional brain imaging, endoscopy, exercise medicine, and monitoring the photodynamic therapy and progress of neoadjuvant chemotherapy. In the past three decades, in vivo diffuse optical breast cancer imaging has shown promising results in cancer detection, and monitoring the progress of neoadjuvant chemotherapy. The use of near infrared spectroscopy for functional brain imaging has been growing rapidly. In fluorescence imaging, the difference between autofluorescence of cancer lesions compared to normal tissues were used in endoscopy to distinguish malignant lesions from normal tissue or inflammation and in determining the boarders of cancer lesions in surgery. Recent advances in drugs targeting specific tumor receptors, such as AntiBodies (MAB), has created a new demand for developing non-invasive in vivo imaging techniques for detection of cancer biomarkers, and for monitoring their down regulations during therapy. Targeted treatments, combined with new imaging techniques, are expected to potentially result in new imaging and treatment paradigms in cancer therapy. Similar approaches can potentially be applied for the characterization of other disease-related biomarkers. In this chapter, we provide a review of diffuse optical and fluorescence imaging techniques with their application in functional brain imaging and cancer diagnosis. PMID:22433452

Ardeshirpour, Yasaman; Gandjbakhche, Amir H.; Najafizadeh, Laleh

2014-01-01

287

Blind-deconvolution optical-resolution photoacoustic microscopy in vivo.  

PubMed

Optical-resolution photoacoustic microscopy (OR-PAM) is becoming a vital tool for studying the microcirculation system in vivo. By increasing the numerical aperture of optical focusing, the lateral resolution of OR-PAM can be improved; however, the depth of focus and thus the imaging range will be sacrificed correspondingly. In this work, we report our development of blind-deconvolution optical-resolution photoacoustic microscopy (BD-PAM) that can provide a lateral resolution ~2-fold finer than that of conventional OR-PAM (3.04 vs. 5.78?m), without physically increasing the system's numerical aperture. The improvement achieved with BD-PAM is demonstrated by imaging graphene nanoparticles and the microvasculature of mice ears in vivo. Our results suggest that BD-PAM may become a valuable tool for many biomedical applications that require both fine spatial resolution and extended depth of focus. PMID:23546115

Chen, Jianhua; Lin, Riqiang; Wang, Huina; Meng, Jing; Zheng, Hairong; Song, Liang

2013-03-25

288

In vivo photoacoustic imaging of model of port wine stains.  

PubMed

Port wine stains are categorized as a benign capillary vascular malformation, which is hard to cure. In this paper, a photoacoustic microscopy system, which integrated a two-dimensional scanning galvanometer, an objective lens and a focused ultrasound transducer, was designed for noninvasive imaging of blood vessels of port wine stains model in vivo. Cock comb was chosen as the port wine stains model in the experiment. The blood vessels in x-y plane and x-z plane were imaged clearly. Experimental results demonstrate that photoacoustic microscopy can image the blood vessels of port wine stains model in vivo with high contrast and high resolution. It has the potential for clinical applications in detecting the blood vessels in port wine stains skin. PMID:22635179

Yuan, Kaihua; Yuan, Yi; Gu, Ying; Gao, Jianhua; Xing, Da

2012-01-01

289

In vivo recordings of brain activity using organic transistors  

PubMed Central

In vivo electrophysiological recordings of neuronal circuits are necessary for diagnostic purposes and for brain-machine interfaces. Organic electronic devices constitute a promising candidate because of their mechanical flexibility and biocompatibility. Here we demonstrate the engineering of an organic electrochemical transistor embedded in an ultrathin organic film designed to record electrophysiological signals on the surface of the brain. The device, tested in vivo on epileptiform discharges, displayed superior signal-to-noise ratio due to local amplification compared with surface electrodes. The organic transistor was able to record on the surface low-amplitude brain activities, which were poorly resolved with surface electrodes. This study introduces a new class of biocompatible, highly flexible devices for recording brain activity with superior signal-to-noise ratio that hold great promise for medical applications. PMID:23481383

Khodagholy, Dion; Doublet, Thomas; Quilichini, Pascale; Gurfinkel, Moshe; Leleux, Pierre; Ghestem, Antoine; Ismailova, Esma; Hervé, Thierry; Sanaur, Sébastien; Bernard, Christophe; Malliaras, George G.

2013-01-01

290

In vivo biodistribution and clearance of peptide amphiphile micelles.  

PubMed

Peptide amphiphiles (PAs) are promising biomaterials for medical applications. To translate the use of PAs successfully from laboratories to clinics, in vivo studies regarding the safety of these nanomaterials are required. To examine the toxicity and clearance of PA biomaterials, we intravenously administered cy7-labeled, spherical PA micelles, control micelles without a peptide sequence, or PBS in a murine model and investigated biocompatibility, biodistribution, and clearance. Both peptide and non-peptide labeled micelles were approximately 8nm in diameter, but of opposite surface charge. Neither micelle type caused aggregation or hemolysis of red blood cells. All micelles primarily accumulated in the bladder and were present in urine samples confirming elimination through renal clearance. Ex vivo imaging showed that micelles were also found in the liver suggesting some involvement of the reticuloendothelial system. However, no evidence of toxicity was found within the liver, spleen, kidney, bladder, intestines, lung, and heart. PMID:25194999

Chung, Eun Ji; Mlinar, Laurie B; Sugimoto, Matthew J; Nord, Kathryn; Roman, Brian B; Tirrell, Matthew

2014-09-01

291

Manganese ferrite-based nanoparticles induce ex vivo, but not in vivo, cardiovascular effects  

PubMed Central

Magnetic nanoparticles (MNPs) have been used for various biomedical applications. Importantly, manganese ferrite-based nanoparticles have useful magnetic resonance imaging characteristics and potential for hyperthermia treatment, but their effects in the cardiovascular system are poorly reported. Thus, the objectives of this study were to determine the cardiovascular effects of three different types of manganese ferrite-based magnetic nanoparticles: citrate-coated (CiMNPs); tripolyphosphate-coated (PhMNPs); and bare magnetic nanoparticles (BaMNPs). The samples were characterized by vibrating sample magnetometer, X-ray diffraction, dynamic light scattering, and transmission electron microscopy. The direct effects of the MNPs on cardiac contractility were evaluated in isolated perfused rat hearts. The CiMNPs, but not PhMNPs and BaMNPs, induced a transient decrease in the left ventricular end-systolic pressure. The PhMNPs and BaMNPs, but not CiMNPs, induced an increase in left ventricular end-diastolic pressure, which resulted in a decrease in a left ventricular end developed pressure. Indeed, PhMNPs and BaMNPs also caused a decrease in the maximal rate of left ventricular pressure rise (+dP/dt) and maximal rate of left ventricular pressure decline (?dP/dt). The three MNPs studied induced an increase in the perfusion pressure of isolated hearts. BaMNPs, but not PhMNPs or CiMNPs, induced a slight vasorelaxant effect in the isolated aortic rings. None of the MNPs were able to change heart rate or arterial blood pressure in conscious rats. In summary, although the MNPs were able to induce effects ex vivo, no significant changes were observed in vivo. Thus, given the proper dosages, these MNPs should be considered for possible therapeutic applications. PMID:25031535

Nunes, Allancer DC; Ramalho, Laylla S; Souza, Álvaro PS; Mendes, Elizabeth P; Colugnati, Diego B; Zufelato, Nícholas; Sousa, Marcelo H; Bakuzis, Andris F; Castro, Carlos H

2014-01-01

292

Determination of the in vivo degradation mechanism of PEGDA hydrogels.  

PubMed

Poly(ethylene glycol) (PEG) hydrogels are one of the most extensively utilized biomaterials systems due to their established biocompatibility and highly tunable properties. It is widely acknowledged that traditional acrylate-derivatized PEG (PEGDA) hydrogels are susceptible to slow degradation in vivo and are therefore unsuitable for long-term implantable applications. However, there is speculation whether the observed degradation is due to hydrolysis of endgroup acrylate esters or oxidation of the ether backbone, both of which are possible in the foreign body response to implanted devices. PEG diacrylamide (PEGDAA) is a polyether-based hydrogel system with similar properties to PEGDA but with amide linkages in place of the acrylate esters. This provides a hydrolytically-stable control that can be used to isolate the relative contributions of hydrolysis and oxidation to the in vivo degradation of PEGDA. Here we show that PEGDAA hydrogels remained stable over 12 weeks of subcutaneous implantation in a rat model while PEGDA hydrogels underwent significant degradation as indicated by both increased swelling ratio and decreased modulus. As PEGDA and PEGDAA have similar susceptibility to oxidation, these results demonstrate for the first time that the primary in vivo degradation mechanism of PEGDA is hydrolysis of the endgroup acrylate esters. Additionally, the maintenance of PEGDAA hydrogel properties in vivo indicates their suitability for long-term implants. These studies serve to elucidate key information about a widely used biomaterial system to allow for better implantable device design and to provide a biostable replacement option for PEGDA in applications that require long-term stability. PMID:24464985

Browning, M B; Cereceres, S N; Luong, P T; Cosgriff-Hernandez, E M

2014-12-01

293

Oxygen sensing glucose biosensors based on alginate nano-micro systems  

NASA Astrophysics Data System (ADS)

Clinically glucose monitoring in diabetes management is done by point-measurement. However, an accurate, continuous glucose monitoring, and minimally invasive method is desirable. The research aims at developing fluorescence-mediated glucose detecting biosensors based on near-infrared radiation (NIR) oxygen sensitive dyes. Biosensors based on Glucose oxidase (GOx)-Rudpp loaded alginate microspheres (GRAM) and GOx-Platinum-octaethylporphyrin (PtOEP)-PLAalginate microsphere system (GPAM) were developed using air-driven atomization and characterized using optical microscopy, CLSM, fluorescence spectro-photometry etc. Biosensing studies were performed by exposing standard solutions of glucose. Uniform sized GRAM and GPAM with size 50+/-10?m were formed using atomization. CLSM imaging of biosensors suggests that Rudpp and PtOEP nanoparticles are uniformly distributed in alginate microspheres. The GRAM and GPAM showed a good regression constant of 0.974 and of 0.9648 over a range of 0-10 mM of glucose with a high sensitivity of 3.349%/mM (625 nm) and 2.38%/mM (645 nm) at 10 mM of glucose for GRAM and GPAM biosensor. GRAM and GPAM biosensors show great potential in development of an accurate and minimally invasive glucose biosensor. NIR dye based assays can aid sensitive, minimally-invasive and interference-free detection of glucose in diabetic patients.

Chaudhari, Rashmi; Joshi, Abhijeet; Srivastava, Rohit

2014-04-01

294

Mechanisms of acute oxygen sensing by the carotid body: Lessons from genetically modified animals  

Microsoft Academic Search

We have studied carotid body (CB) glomus cell sensitivity to changes in O2 tension in three different genetically engineered animals models using thin CB slices and monitoring the secretory response to hypoxia by amperometry. Glomus cells from partially HIF-1? deficient mice exhibited a normal sensitivity to hypoxia. Animals with complete deletion of the small membrane anchoring subunit of succinate dehydrogenase

Patricia Ortega-Sáenz; Alberto Pascual; José I. Piruat; José López-Barneo

2007-01-01

295

Global Oxygen Sensing and Visualization in Water using Luminescent Probe on Anodized Aluminum  

NASA Astrophysics Data System (ADS)

The extension of pressure-sensitive paint (PSP) technique as a wind tunnel technology to a global oxygen visualization and detection in water is presented. The topic includes the development of anodized-aluminum pressure-sensitive paint (AA-PSP) as a global oxygen sensor in water as well as its calibration and demonstration. Based on the luminophore study, platinum porphyrin is selected as a luminophore, because it is not dissolved in water. It is found that the luminescent increase is over 20 percent after 8 days immersed in water. Even though the signal increases after water immersion, its oxygen sensitivity is the same, which is 0.4. This AA-PSP is used to visualize oxygen rich water (20 mg/l) impinged in less oxygen water (3 mg/l). Even though the difference of water is only the amount of oxygen, we can visualize the water jet with its mixing process using a fast frame rate camera at the frame rate of 100 Hz. In the final version, we will include the oxygen map combined with the visualization result.

Ozaki, Tatsuya; Ishikawa, Hitoshi; Iijima, Yoshimi; Sakaue, Hirotaka

2008-11-01

296

HIF-1? in epidermis: oxygen sensing, cutaneous angiogenesis, cancer, and non-cancer disorders.  

PubMed

Besides lung, postnatal human epidermis is the only epithelium in direct contact with atmospheric oxygen. Skin epidermal oxygenation occurs mostly through atmospheric oxygen rather than tissue vasculature, resulting in a mildly hypoxic microenvironment that favors increased expression of hypoxia-inducible factor-1? (HIF-1?). Considering the wide spectrum of biological processes, such as angiogenesis, inflammation, bioenergetics, proliferation, motility, and apoptosis, that are regulated by this transcription factor, its high expression level in the epidermis might be important to HIF-1? in skin physiology and pathophysiology. Here, we review the role of HIF-1? in cutaneous angiogenesis, skin tumorigenesis, and several skin disorders. PMID:21633368

Rezvani, Hamid R; Ali, Nsrein; Nissen, Lars J; Harfouche, Ghida; de Verneuil, Hubert; Taïeb, Alain; Mazurier, Frédéric

2011-09-01

297

The effect of high light intensities on luminescence lifetime based oxygen sensing.  

PubMed

This study highlights possible errors in luminescence lifetime measurements when using bright optical oxygen sensors with high excitation light intensities. An analysis of the sensor with a mathematical model shows that high light intensities will cause a depopulation of the ground state of the luminophore, which results in a non-linear behaviour of the luminescence emission light with respect to the excitation light. The effect of this non-linear behaviour on different lifetime determination methods, including phase-fluorometry, is investigated and in good agreement with the output of the model. Furthermore, the consequences of increasingly high light intensities on phase fluorometric lifetime measurements are illustrated for different oxygen sensors based on benzoporphyrin indicators. For the specific case of PdTPTBPF-based sensors an error as high as 50% is possible under high light conditions (0.25 mol m(-2) s(-1) ? 50 mW mm(-2)). A threshold of applied excitation light intensity is derived, thus enabling the point at which errors become significant to be estimated. Strategies to further avoid such errors are presented. The model also predicts a similar depopulation of the ground state of the quencher; however, the effect of this process was not seen in lab measurements. Possible explanations for this deviation are discussed. PMID:25364788

Larndorfer, Christoph; Borisov, Sergey M; Lehner, Philipp; Klimant, Ingo

2014-12-21

298

Enhanced performance from a hybrid quenchometric deoxyribonucleic acid (DNA) silica xerogel gaseous oxygen sensing platform.  

PubMed

A complex of salmon milt deoxyribonucleic acid (DNA) and the cationic surfactant cetyltrimethylammonium (CTMA) forms an organic-soluble biomaterial that can be readily incorporated within an organically modified silane-based xerogel. The photoluminescence (PL) intensity and excited-state luminescence lifetime of tris(4,7'-diphenyl-1,10'-phenanathroline) ruthenium(II) [(Ru(dpp)3](2+), a common O2 responsive luminophore, increases in the presence of DNA-CTMA within the xerogel. The increase in the [Ru(dpp)3](2+)excited-state lifetime in the presence of DNA-CTMA arises from DNA intercalation that attenuates one or more non-radiative processes, leading to an increase in the [Ru(dpp)3](2+) excited-state lifetime. Prospects for the use of these materials in an oxygen sensor are demonstrated. PMID:25280266

Zhou, Bin; Liu, Ke; Liu, Xin; Yung, Ka Yi; Bartsch, Carrie M; Heckman, Emily M; Bright, Frank V; Swihart, Mark T; Cartwright, Alexander N

2014-01-01

299

Chromatin and oxygen sensing in the context of JmjC histone demethylases  

PubMed Central

Responding appropriately to changes in oxygen availability is essential for multicellular organism survival. Molecularly, cells have evolved intricate gene expression programmes to handle this stressful condition. Although it is appreciated that gene expression is co-ordinated by changes in transcription and translation in hypoxia, much less is known about how chromatin changes allow for transcription to take place. The missing link between co-ordinating chromatin structure and the hypoxia-induced transcriptional programme could be in the form of a class of dioxygenases called JmjC (Jumonji C) enzymes, the majority of which are histone demethylases. In the present review, we will focus on the function of JmjC histone demethylases, and how these could act as oxygen sensors for chromatin in hypoxia. The current knowledge concerning the role of JmjC histone demethylases in the process of organism development and human disease will also be reviewed. PMID:25145438

Shmakova, Alena; Batie, Michael; Druker, Jimena; Rocha, Sonia

2014-01-01

300

Chromatin and oxygen sensing in the context of JmjC histone demethylases.  

PubMed

Responding appropriately to changes in oxygen availability is essential for multicellular organism survival. Molecularly, cells have evolved intricate gene expression programmes to handle this stressful condition. Although it is appreciated that gene expression is co-ordinated by changes in transcription and translation in hypoxia, much less is known about how chromatin changes allow for transcription to take place. The missing link between co-ordinating chromatin structure and the hypoxia-induced transcriptional programme could be in the form of a class of dioxygenases called JmjC (Jumonji C) enzymes, the majority of which are histone demethylases. In the present review, we will focus on the function of JmjC histone demethylases, and how these could act as oxygen sensors for chromatin in hypoxia. The current knowledge concerning the role of JmjC histone demethylases in the process of organism development and human disease will also be reviewed. PMID:25145438

Shmakova, Alena; Batie, Michael; Druker, Jimena; Rocha, Sonia

2014-09-15

301

Human oxygen sensing may have origins in prokaryotic elongation factor Tu prolyl-hydroxylation.  

PubMed

The roles of 2-oxoglutarate (2OG)-dependent prolyl-hydroxylases in eukaryotes include collagen stabilization, hypoxia sensing, and translational regulation. The hypoxia-inducible factor (HIF) sensing system is conserved in animals, but not in other organisms. However, bioinformatics imply that 2OG-dependent prolyl-hydroxylases (PHDs) homologous to those acting as sensing components for the HIF system in animals occur in prokaryotes. We report cellular, biochemical, and crystallographic analyses revealing that Pseudomonas prolyl-hydroxylase domain containing protein (PPHD) contain a 2OG oxygenase related in structure and function to the animal PHDs. A Pseudomonas aeruginosa PPHD knockout mutant displays impaired growth in the presence of iron chelators and increased production of the virulence factor pyocyanin. We identify elongation factor Tu (EF-Tu) as a PPHD substrate, which undergoes prolyl-4-hydroxylation on its switch I loop. A crystal structure of PPHD reveals striking similarity to human PHD2 and a Chlamydomonas reinhardtii prolyl-4-hydroxylase. A crystal structure of PPHD complexed with intact EF-Tu reveals that major conformational changes occur in both PPHD and EF-Tu, including a >20-Å movement of the EF-Tu switch I loop. Comparison of the PPHD structures with those of HIF and collagen PHDs reveals conservation in substrate recognition despite diverse biological roles and origins. The observed changes will be useful in designing new types of 2OG oxygenase inhibitors based on various conformational states, rather than active site iron chelators, which make up most reported 2OG oxygenase inhibitors. Structurally informed phylogenetic analyses suggest that the role of prolyl-hydroxylation in human hypoxia sensing has ancient origins. PMID:25197067

Scotti, John S; Leung, Ivanhoe K H; Ge, Wei; Bentley, Michael A; Paps, Jordi; Kramer, Holger B; Lee, Joongoo; Aik, WeiShen; Choi, Hwanho; Paulsen, Steinar M; Bowman, Lesley A H; Loik, Nikita D; Horita, Shoichiro; Ho, Chia-hua; Kershaw, Nadia J; Tang, Christoph M; Claridge, Timothy D W; Preston, Gail M; McDonough, Michael A; Schofield, Christopher J

2014-09-16

302

Two-Photon Oxygen Sensing with Quantum Dot-Porphyrin Conjugates  

E-print Network

Supramolecular assemblies of a quantum dot (QD) associated to palladium(II) porphyrins have been developed to detect oxygen (pO[subscript 2]) in organic solvents. Palladium porphyrins are sensitive in the 0–160 Torr range, ...

Lemon, Christopher M.

303

Uncoupling hypoxia signaling from oxygen sensing in the liver results in hypoketotic hypoglycemic death  

Microsoft Academic Search

As the ultimate electron acceptor in oxidative phosphorylation, oxygen plays a critical role in metabolism. When oxygen levels drop, heterodimeric hypoxia-inducible factor (Hif) transcription factors become active and facilitate adaptation to hypoxia. Hif regulation by oxygen requires the protein von Hippel-Lindau (pVhl) and pVhl disruption results in constitutive Hif activation. The liver is a critical organ for metabolic homeostasis, and

B Kucejova; N E Sunny; A D Nguyen; R Hallac; X Fu; S Peña-Llopis; R P Mason; R J DeBerardinis; X-J Xie; R DeBose-Boyd; V D Kodibagkar; S C Burgess; J Brugarolas

2011-01-01

304

Development of an integrated microfluidic platform for oxygen sensing and delivery  

E-print Network

Treatment for end stage lung disease has failed to benefit from advances in medical technology that have produced new treatments for cardiovascular disease, certain cancers, and other major illnesses in recent years. As a ...

Vollmer, Adam P

2005-01-01

305

Optical stimulation of peripheral nerves in vivo  

NASA Astrophysics Data System (ADS)

This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

Wells, Jonathon D.

306

PEI protected aptamer molecular probes for contrast-enhanced in vivo cancer imaging.  

PubMed

Aptamers have emerged as promising molecular probes for cancer diagnosis. However, their application for in vivo cancer imaging remains limitation due to the poor stability in blood and the degradation by nucleases. In the present study, we generated PEI/aptamer molecular complexes for cancer imaging in vivo by using deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) to monitor DNA degradation. The results showed that the complexes with PEI at the N/P ratio from 3.8 to 15 effectively prevented the degradation of DFProbes both in vitro and in vivo. Moreover, PEI successfully protected TD05 aptamers from DNase degradation without affecting its specific recognition of Ramos cells. In tumor bearing mice, PEI/aptamer molecular complexes further demonstrated superior passive tumor targeting and extended circulation time as compared with free aptamer. Hence, the well-defined PEI/aptamer probe is a novel strategy to deliver targeted aptamer for tumor diagnosis and imaging in vivo. PMID:22835645

Gong, Ping; Shi, Bihua; Zheng, Mingbin; Wang, Bi; Zhang, Pengfei; Hu, Dehong; Gao, Duyang; Sheng, Zonghai; Zheng, Cuifang; Ma, Yifan; Cai, Lintao

2012-11-01

307

In vivo dosimetry in brachytherapy  

SciTech Connect

In vivo dosimetry (IVD) has been used in brachytherapy (BT) for decades with a number of different detectors and measurement technologies. However, IVD in BT has been subject to certain difficulties and complexities, in particular due to challenges of the high-gradient BT dose distribution and the large range of dose and dose rate. Due to these challenges, the sensitivity and specificity toward error detection has been limited, and IVD has mainly been restricted to detection of gross errors. Given these factors, routine use of IVD is currently limited in many departments. Although the impact of potential errors may be detrimental since treatments are typically administered in large fractions and with high-gradient-dose-distributions, BT is usually delivered without independent verification of the treatment delivery. This Vision 20/20 paper encourages improvements within BT safety by developments of IVD into an effective method of independent treatment verification.

Tanderup, Kari [Department of Oncology, Aarhus University Hospital, Aarhus 8000 (Denmark); Department of Clinical Medicine, Aarhus University, Aarhus 8000 (Denmark); Beddar, Sam [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Andersen, Claus E.; Kertzscher, Gustavo [Center of Nuclear Technologies, Technical University of Denmark, Roskilde 4000 (Denmark); Cygler, Joanna E. [Department of Physics, Ottawa Hospital Cancer Centre, Ottawa, Ontario K1H 8L6 (Canada)

2013-07-15

308

In vivo correlates of altered blood rheology  

Microsoft Academic Search

It is has been known for more than 80 years that compared to in vitro determinations, blood behaves as a less viscous fluid under in vivo flow conditions. The experiments of Whittaker and Winton were among the first dealing with the in vivo effects of altered blood rheology, and experimental studies during the second half of 20th century have provided

Oguz K. Baskurt

2008-01-01

309

Imaging axonal transport of mitochondria in vivo  

E-print Network

Imaging axonal transport of mitochondria in vivo Thomas Misgeld1,2,5, Martin Kerschensteiner1,3,5, Florence M Bareyre1,3, Robert W Burgess4 & Jeff W Lichtman1 Neuronal mitochondria regulate synaptic and sustained changes in anterograde and retrograde transport. In vivo imaging of mitochondria will be a useful

Cai, Long

310

Optical techniques for tracking cells in vivo  

Microsoft Academic Search

I will focus on tracking cancer cells, immune cells, and stem cells in vivo using (i) intravital microscopy for 3D tissue imaging, and (ii) in vivo flow cytometry for detection and quantification of circulating cells. Cell tracking is the process of monitoring how certain cell populations move, or \\

Charles P. Lin

2011-01-01

311

In-vivo photoacoustic microscopy of nanoshell  

E-print Network

In-vivo photoacoustic microscopy of nanoshell extravasation from solid tumor vasculature Meng extravasation and accumulation of nanoshells within a solid tumor in vivo. PAM takes advan- tage of the strong near-infrared absorption of nanoshells and their extravasation tendency from leaky tumor vascu- latures

Wang, Lihong

312

Computer simulation of cardiac cryoablation: comparison with in vivo data.  

PubMed

Simulation of cardiac cryoablation by the finite element method can contribute to optimizing ablation results and understanding the effects of modifications prior to time-consuming and expensive experiments. In this work an intervention scenario using a 9 Fr 8 mm tip applicator applied to ventricular tissue was simulated using the effective heat capacity model based on Pennes' bioheat equation. Using experimentally obtained refrigerant flow rates and temperature profiles recorded by a thermocouple located at the tip of the applicator the cooling performance of the refrigerant was estimated and integrated by time and temperature dependent boundary conditions based on distinct phases of a freeze-thaw cycle. Our simulations exhibited a mean difference of approximately 6°C at the applicator tip compared to temperature profiles obtained during in vivo experiments. The presented model is a useful tool for simulation and validation of new developments in clinical cardiac cryoablation. PMID:23972331

Handler, Michael; Fischer, Gerald; Seger, Michael; Kienast, Roland; Nowak, Claudia-Nike; Pehböck, Daniel; Hintringer, Florian; Baumgartner, Christian

2013-12-01

313

Quantum Dot-Based Nanoprobes for In Vivo Targeted Imaging  

PubMed Central

Fluorescent semiconductor quantum dots (QDs) have attracted tremendous attention over the last decade. The superior optical properties of QDs over conventional organic dyes make them attractive labels for a wide variety of biomedical applications, whereas their potential toxicity and instability in biological environment has puzzled scientific researchers. Much research effort has been devoted to surface modification and functionalization of QDs to make them versatile probes for biomedical applications, and significant progress has been made over the last several years. This review article aims to describe the current state-of-the-art of the synthesis, modification, bioconjugation, and applications of QDs for in vivo targeted imaging. In addition, QD-based multifunctional nanoprobes are also summarized. PMID:24206136

Zhu, Yian; Hong, Hao; Xu, Zhi Ping; Li, Zhen; Cai, Weibo

2013-01-01

314

In vitro and in vivo genotoxicity of silver nanoparticles.  

PubMed

The biocidal effect of silver nanoparticles (Ag-np) has resulted in their incorporation into consumer products. While the population exposed to Ag-np continues to increase with ever new applications, Ag-np remains a controversial research area with regard to their toxicity in biological systems. Here a genotoxic and cytotoxic approach was employed to elucidate the activity of Ag-np in vitro and in vivo. Characterization of Ag-np using scanning electron microscopy revealed a size range of 90-180nm. Cytotoxic potential of Ag-np was evaluated in human lymphocytes via cell viability assay (Trypan blue dye exclusion method, MTT and WST assay). The uptake and incorporation of Ag-np into the lymphocytes was confirmed by flow cytometry. Additionally apoptosis (AnnexinV-FITC-PI staining) and DNA strand breaks (comet assay) in human lymphocytes revealed that Ag-np at concentration 25?g/ml can cause genotoxicity. In vivo experiments on plants (Allium cepa and Nicotiana tabacum) and animal (Swiss albino male mice) showed impairment of nuclear DNA. Induction of oxidative stress was also studied. The DNA damage and chromosomal aberrations raise the concern about the safety associated with applications of the Ag-np. A single ip administration of Ag-np gave a significant (P?0.05) increase in the frequency of aberrant cells and Tail DNA percent at concentrations 10mg/kg body weight and above. Results of comet assay in A. cepa and N. tabacum demonstrated that the genotoxic effect of Ag-np was more pronounced in root than shoot/leaf of the plants. The present study indicated a good correlation between the in vitro and in vivo experiments. Therefore the biological applications employing Ag-np should be given special attention besides adapting the antimicrobial potential. PMID:22960309

Ghosh, Manosij; J, Manivannan; Sinha, Sonali; Chakraborty, Anirban; Mallick, Sanjaya Kumar; Bandyopadhyay, Maumita; Mukherjee, Anita

2012-12-12

315

Viscous optical clearing agent for in vivo optical imaging  

NASA Astrophysics Data System (ADS)

By allowing more photons to reach deeper tissue, the optical clearing agent (OCA) has gained increasing attention in various optical imaging modalities. However, commonly used OCAs have high fluidity, limiting their applications in in vivo studies with oblique, uneven, or moving surfaces. In this work, we reported an OCA with high viscosity. We measured the properties of this viscous OCA, and tested its successful performances in the imaging of a living animal's skin with two optical imaging modalities: photoacoustic microscopy and optical coherence tomography. Our results demonstrated that the viscous OCA has a great potential in the study of different turbid tissues using various optical imaging modalities.

Deng, Zijian; Jing, Lijia; Wu, Ning; lv, Pengyu; Jiang, Xiaoyun; Ren, Qiushi; Li, Changhui

2014-07-01

316

In-vivo Reflectance Measurements from Human Skin  

NASA Astrophysics Data System (ADS)

We evaluate the potential of using a standard commercial spectrophotometer, specifically designed to meet the growing requirement for color control in the digital-imaging application field, to perform in-vivo diffuse reflectance measurements from adult human skin. We report and discuss diffuse reflectance spectra for three practical situations: a) reflectance versus skin type, b) reflectance from normal skin with different grade of solar exposition, c) reflectance from normal skin versus reflectance from seborrheic keratosis. Results show, that using the above spectrophotometer we can easily differentiate two sites of different solar exposition. Besides, significant differences are found in the normal skin diffuse reflectance for patients with different skin types.

Delgado, J. A.; Cornejo, A.; Cunill, M.; Báez, J. J.; Matos, R.; Anasagasti, L.; Santiago, C.

2006-09-01

317

Bone marrow stromal cell assays – in vitro and in vivo  

PubMed Central

Summary Populations of bone marrow stromal cells (BMSCs, also known as bone marrow-derived “mesenchymal stem cells”) contain a a subset of cells that are able to recapitulate the formation of a bone/marrow organ (skeletal stem cells, SSCs). The biological properties of BMSC cultures are assessed by a variety of assays, both in vitro and in vivo. Application of these assays in an appropriate fashion provide a great deal of information on the role of BMSCs, and the subset of SSCs, in health and in disease. PMID:24482181

Robey, Pamela Gehron; Kuznetsov, Sergei A.; Riminucci, Mara; Bianco, Paolo

2014-01-01

318

Fructation In Vivo: Detrimental and Protective Effects of Fructose  

PubMed Central

There is compelling evidence that long-term intake of excessive fructose can have deleterious side effects in different experimental models. However, the role of fructose in vivo remains controversial, since acute temporary application of fructose is found to protect yeast as well as animal tissues against exogenous oxidative stress. This review suggests the involvement of reactive carbonyl and oxygen species in both the cytotoxic and defensive effects of fructose. Potential mechanisms of the generation of reactive species by fructose in the nonenzymatic reactions, their implication in the detrimental and protective effects of fructose are discussed. PMID:23984346

Semchyshyn, H. M.

2013-01-01

319

Technical development of a new semispherical radiofrequency bipolar device (RONJA): ex vivo and in vivo studies.  

PubMed

The aim of this study is to inform about the development of a new semispherical surgical instrument for the bipolar multielectrode radiofrequency liver ablation. Present tools are universal; however they have several disadvantages such as ablation of healthy tissue, numerous needle punctures, and, therefore, longer operating procedure. Our newly designed and tested semispherical surgical tool can solve some of these disadvantages. By conducting an in vivo study on a set of 12 pigs, randomly divided into two groups, we have compared efficiency of the newly developed instrument with the commonly used device. Statistical analysis showed that there were no significant differences between the groups. On average, the tested instrument RONJA had shorter ablation time in both liver lobes and reduced the total operating time. The depth of the thermal alteration was on average 4 mm larger using the newly tested instrument. The new radiofrequency method described in this study could be used in open liver surgery for the treatment of small liver malignancies (up to 2 cm) in a single application with the aim of saving healthy liver parenchyma. Further experimental studies are needed to confirm these results before clinical application of the method in the treatment of human liver malignancies. PMID:24812620

Vavra, Petr; Penhaker, Marek; Grepl, Jan; Jurcikova, Jana; Palecek, Jiri; Crha, Michal; Nowakova, Jana; Hasal, Martin; Skrobankova, Martina; Ostruszka, Petr; Ihnat, Peter; Delongova, Patricie; Salounova, Dana; Habib, Nagy A; Zonca, Pavel

2014-01-01

320

Use of an optical clearing agent during noninvasive laser coagulation of the canine vas deferens, ex vivo and in vivo  

NASA Astrophysics Data System (ADS)

Development of a noninvasive vasectomy technique may eliminate male fear of complications and result in a more popular procedure. This study explores application of an optical clearing agent (OCA) to the scrotal skin to reduce both the laser power necessary for successful noninvasive laser vasectomy and the probability of scrotal skin burns. A mixture of DMSO/glycerol was noninvasively delivered into the scrotal skin using a Madajet. Near-infrared laser radiation with a range of average powers (7.0-11.7 W) was delivered in conjunction with a range of cryogen spray cooling rates (0.20-0.33 Hz) to the skin surface in a canine model, ex vivo and in vivo. Burst pressure (BP) measurements were conducted to quantify the strength of vas closure. A 30-min application of the OCA improved skin transparency by 26 +/- 5 %, reducing the average power necessary for successful noninvasive laser vasectomy from 9.2 W without OCA (BP = 291 +/- 31 mmHg) to 7.0 W with OCA (BP = 292 +/- 19 mmHg). Control studies without OCA at 7.0 W failed to coagulate the vas with burst pressures (82 +/- 28 mmHg) significantly below typical ejaculation pressures (136 +/- 29 mmHg). Application of an optical clearing agent reduced the laser power necessary for successful noninvasive thermal coagulation of the vas by approximately 25%. This technique may result in the use of a less expensive laser system and eliminate the formation of scrotal skin burns during the procedure.

Cilip, Christopher M.; Ross, Ashley E.; Jarow, Jonathan P.; Fried, Nathaniel M.

2010-02-01

321

Toward lower contrast computer vision in vivo flow cytometry.  

PubMed

There are many applications in biomedical research where detection and enumeration of circulating cells (CCs) is important. Existing techniques involve drawing and enriching blood samples and analyzing them ex vivo. More recently, small animal "in vivo flow cytometry" (IVFC) techniques have been developed, where fluorescently-labeled cells flowing through small arterioles (ear, retina) are detected and counted. We recently developed a new high-sensitivity IVFC technique termed "Computer Vision(CV)-IVFC". Here, large circulating blood volumes were monitored in the ears of mice with a wide-field video-rate near-infrared (NIR) fluorescent camera. Cells were labeled with a membrane dye and were detected and tracked in noisy image sequences. This technique allowed enumeration of CCs in vivo with overall sensitivity better than 10 cells/mL. However, an ongoing area of interest in our lab is optimization of the system for lower-contrast imaging conditions, e.g. when CCs are weakly labeled, or in the case higher background autofluorescence with visible dyes. To this end, we developed a new optical flow phantom model to control autofluorescence intensity and physical structure to better mimic conditions observed in mice. We acquired image sequences from a series of phantoms with varying levels of contrast and analyzed the distribution of pixel intensities, and showed that we could generate similar conditions to those in vivo. We characterized the performance of our CV-IVFC algorithm in these phantoms with respect to sensitivity and false-alarm rates. Use of this phantom model in optimization of the instrument and algorithm under lower-contrast conditions is the subject of ongoing work in our lab. PMID:25570932

Markovic, Stacey; Siyuan Li; Tianxue Zhang; Niedre, Mark

2014-08-01

322

Multidimensional custom-made non-linear microscope: from ex-vivo to in-vivo imaging  

NASA Astrophysics Data System (ADS)

We have built a custom-made multidimensional non-linear microscope equipped with a combination of several non-linear laser imaging techniques involving fluorescence lifetime, multispectral two-photon and second-harmonic generation imaging. The optical system was mounted on a vertical honeycomb breadboard in an upright configuration, using two galvo-mirrors relayed by two spherical mirrors as scanners. A double detection system working in non-descanning mode has allowed both photon counting and a proportional regime. This experimental setup offering high spatial (micrometric) and temporal (sub-nanosecond) resolution has been used to image both ex-vivo and in-vivo biological samples, including cells, tissues, and living animals. Multidimensional imaging was used to spectroscopically characterize human skin lesions, as malignant melanoma and naevi. Moreover, two-color detection of two photon excited fluorescence was applied to in-vivo imaging of living mice intact neocortex, as well as to induce neuronal microlesions by femtosecond laser burning. The presented applications demonstrate the capability of the instrument to be used in a wide range of biological and biomedical studies.

Cicchi, R.; Sacconi, L.; Jasaitis, A.; O'Connor, R. P.; Massi, D.; Sestini, S.; de Giorgi, V.; Lotti, T.; Pavone, F. S.

2008-09-01

323

In vivo generator for radioimmunotherapy  

DOEpatents

The present invention involves labeling monoclonal antibodies with intermediate half-life radionuclides which decay to much shorter half-life daughters with desirable high energy beta emissions. Since the daughter will be in equilibrium with the parent, it can exert an in-situ tumoricidal effect over a prolonged period in a localized fashion, essentially as an "in-vivo generator". This approach circumvents the inverse relationship between half-life and beta decay energy. Compartmental modeling was used to determine the relative distribution of dose from both parent and daughter nuclei in target and non-target tissues. Actual antibody biodistribution data have been used to fit realistic rate constants for a model containing tumor, blood, and non-tumor compartments. These rate constants were then used in a variety of simulations for two generator systems, Ba-128/Cs-128 (t.sub.1/2 =2.4d/3.6m) and Pd-112/Ag-112 (t.sub.1/2 =0.9d/192m). The results show that higher tumor/background dose ratios may be achievable by virtue of the rapid excretion of a chemically different daughter during the uptake and clearance phases. This modeling also quantitatively demonstrates the favorable impact on activity distribution of a faster monoclonal antibody tumor uptake, especially when the antibody is labeled with a radionuclide with a comparable half-life.

Mausner, Leonard F. (Stony Brook, NY); Srivastava, Suresh G. (Setauket, NY); Straub, Rita F. (Brookhaven, NY)

1988-01-01

324

[Estimation on ethanol content measured in vivo].  

PubMed

Recently the cases after drinking are increasing, but the systematic studys on ethanol content in vivo and correlative problems are still absent. According to the measured results of ethanol content in vivo, ethanol metabolic distributed rules, mechanisms of ethanol toxicological effect and its production in vivo, this study analysed systematically the time after drinking, total quantity of absorbed ethanol, psychological situations, behavioral dominated ability, death causes and manners in order to find out the implied forensic medical information and provide the reference for colleague. PMID:16524198

Zhu, De-quan; Pang, Hua; Li, Jin-rong

2006-02-01

325

Novel peptides functionally targeting in vivo human lung cancer discovered by in vivo peptide displayed phage screening.  

PubMed

Discovery of the cancer-specific peptidic ligands have been emphasized for active targeting drug delivery system and non-invasive imaging. For the discovery of useful and applicable peptidic ligands, in vivo peptide-displayed phage screening has been performed in this study using a xenograft mouse model as a mimic microenvironment to tumor. To seek human lung cancer-specific peptides, M13 phage library displaying 2.9 × 10(9) random peptides was intravenously injected into mouse model bearing A549-derived xenograft tumor through the tail vein. Then the phages emerged from a course of four rounds of biopanning in the xenograft tumor tissue. Novel peptides were categorized into four groups according to a sequence-homology phylogenicity, and in vivo tumor-targeting capacity of these peptides was validated by whole body imaging with Cy5.5-labeled phages in various cancer types. The result revealed that novel peptides accumulated only in adenocarcinoma lung cancer cell-derived xenograft tissue. For further confirmation of the specific targeting ability, in vitro cell-binding assay and immunohistochemistry in vivo tumor tissue were performed with a selected peptide. The peptide was found to bind intensely to lung cancer cells both in vitro and in vivo, which was efficiently compromised with unlabeled phages in an in vitro competition assay. In conclusion, the peptides specifically targeting human lung cancer were discovered in this study, which is warranted to provide substantive feasibilities for drug delivery and imaging in terms of a novel targeted therapeutics and diagnostics. PMID:25366491

Lee, Kyoung Jin; Lee, Jae Hee; Chung, Hye Kyung; Choi, Jinhyang; Park, Jaesook; Park, Seok Soon; Ju, Eun Jin; Park, Jin; Shin, Seol Hwa; Park, Hye Ji; Ko, Eun Jung; Suh, Nayoung; Kim, InKi; Hwang, Jung Jin; Song, Si Yeol; Jeong, Seong-Yun; Choi, Eun Kyung

2015-02-01

326

Gravitational physiology of human immune cells: a review of in vivo, ex vivo and in vitro studies  

NASA Technical Reports Server (NTRS)

The study of the function of immune cells in microgravity has been studied for more than 20 years in several laboratories. It is clear today that the immune system is depressed in more than 50% of the astronauts during and after space flight and that the activation of T lymphocytes by mitogens in vitro changes dramatically. This article gives an overview of the gravitational studies conducted by our laboratory in Spacelab, in MIR station, in sounding rockets and on the ground in the clinostat and the centrifuge. Three experimental approaches are followed in our work: (i) Ex vivo studies are performed with blood samples drawn from astronauts; (ii) in vivo studies are based on the application of seven antigens to the skin of the astronauts; (iii) in vitro studies are carried out with immune cells purified from the blood of healthy donors (not astronauts). The data from our in vivo and ex vivo studies are in agreement with those of other laboratories and show that the immunological function is depressed in the majority of astronauts as a consequence of the stress of space flight rather than by a direct influence of gravity on the cell. Immune depression may become a critical hazard on long duration flights on space stations or to other planets. In vitro experiments show that cultures of free-floating lymphocytes and monocytes undergo a dramatic depression of activation by the mitogen concanavalin A, while activation is more than doubled when the cells are attached to microcarrier beads. Such effects may be attributed to both direct and indirect effects of gravitational unloading on basic biological mechanisms of the cell. While the in vitro data are very important to clarify certain aspects of the biological mechanism of T cells activation, they are not descriptive of the changes of the immunological function of the astronauts.

Cogoli, A.

1996-01-01

327

Gravitational physiology of human immune cells: a review of in vivo, ex vivo and in vitro studies.  

PubMed

The study of the function of immune cells in microgravity has been studied for more than 20 years in several laboratories. It is clear today that the immune system is depressed in more than 50% of the astronauts during and after space flight and that the activation of T lymphocytes by mitogens in vitro changes dramatically. This article gives an overview of the gravitational studies conducted by our laboratory in Spacelab, in MIR station, in sounding rockets and on the ground in the clinostat and the centrifuge. Three experimental approaches are followed in our work: (i) Ex vivo studies are performed with blood samples drawn from astronauts; (ii) in vivo studies are based on the application of seven antigens to the skin of the astronauts; (iii) in vitro studies are carried out with immune cells purified from the blood of healthy donors (not astronauts). The data from our in vivo and ex vivo studies are in agreement with those of other laboratories and show that the immunological function is depressed in the majority of astronauts as a consequence of the stress of space flight rather than by a direct influence of gravity on the cell. Immune depression may become a critical hazard on long duration flights on space stations or to other planets. In vitro experiments show that cultures of free-floating lymphocytes and monocytes undergo a dramatic depression of activation by the mitogen concanavalin A, while activation is more than doubled when the cells are attached to microcarrier beads. Such effects may be attributed to both direct and indirect effects of gravitational unloading on basic biological mechanisms of the cell. While the in vitro data are very important to clarify certain aspects of the biological mechanism of T cells activation, they are not descriptive of the changes of the immunological function of the astronauts. PMID:11539302

Cogoli, A

1996-04-01

328

Use of a Single Hybrid Imaging Agent for Integration of Target Validation with In Vivo and Ex Vivo Imaging of Mouse Tumor Lesions Resembling Human DCIS  

PubMed Central

Screening of biomarker expression levels in tumor biopsy samples not only provides an assessment of prognostic and predictive factors, but may also be used for selection of biomarker-specific imaging strategies. To assess the feasibility of using a biopsy specimen for a personalized selection of an imaging agent, the chemokine receptor 4 (CXCR4) was used as a reference biomarker. Methods A hybrid CXCR4 targeting peptide (MSAP-Ac-TZ14011) containing a fluorescent dye and a chelate for radioactive labeling was used to directly compare initial flow cytometry–based target validation in fresh tumor tissue to in vivo single photon emission computed tomography (SPECT) imaging and in vivo and ex vivo fluorescence imaging. Results Flow cytometric analysis of mouse tumor derived cell suspensions enabled discrimination between 4T1 control tumor lesions (with low levels of CXCR4 expression) and CXCR4 positive early, intermediate and late stage MIN-O lesions based on their CXCR4 expression levels; CXCR4basal, CXCR4+ and CXCR4++ cell populations could be accurately discriminated. Mean fluorescent intensity ratios between expression in MIN-O and 4T1 tissue found with flow cytometry were comparable to ratios obtained with in vivo SPECT/CT and fluorescence imaging, ex vivo fluorescence evaluation and standard immunohistochemistry. Conclusion The hybrid nature of a targeting imaging agent like MSAP-Ac-TZ14011 enables integration of target selection, in vivo imaging and ex vivo validation using a single agent. The use of biopsy tissue for biomarker screening can readily be expanded to other targeting hybrid imaging agents and can possibly help increase the clinical applicability of tumor-specific imaging approaches. PMID:23326303

Buckle, Tessa; Kuil, Joeri; van den Berg, Nynke S.; Bunschoten, Anton; Lamb, Hildo J.; Yuan, Hushan; Josephson, Lee; Jonkers, Jos; Borowsky, Alexander D.; van Leeuwen, Fijs W. B.

2013-01-01

329

In vivo hyperpolarized 13C MR spectroscopic imaging with 1H decoupling.  

PubMed

Application of (13)C MRS in vivo on whole body MR system has been limited due to the low static field (and consequent low signal to noise ratio-SNR) of these scanners; thus there have been few reports of (1)H decoupled (13)C MRS in vivo using a clinical MR platform. The recent development of techniques to retain highly polarized spins in solution following DNP in a solid matrix has provided a mechanism to use endogenous pre-polarized (13)C labeled substrates to study real time cellular metabolism in vivo with high SNR. In a recent in vivo hyperpolarized metabolic imaging study using (13)C pyruvate, it has been demonstrated that the line shape (signal decay) of the resonances observed are greatly affected by J(CH) coupling in addition to inhomogeneous broadening. This study demonstrates the feasibility of improving hyperpolarized (13)C metabolic imaging in vivo by incorporating (1)H decoupling on a clinical whole body 3T MR scanner. No reduction of T1 of a pre-polarized (13)C substrate ([1-(13)C] lactate) in solution was observed when (1)H decoupling was applied with WALTZ16 sequence. Narrower linewidth for the [1-(13)C] lactate resonance was observed in hyperpolarized (13)C MRSI data in vivo with (1)H decoupling. PMID:19112035

Chen, Albert P; Tropp, James; Hurd, Ralph E; Van Criekinge, Mark; Carvajal, Lucas G; Xu, Duan; Kurhanewicz, John; Vigneron, Daniel B

2009-03-01

330

Long-term in vivo glucose monitoring using fluorescent hydrogel fibers.  

PubMed

The use of fluorescence-based sensors holds great promise for continuous glucose monitoring (CGM) in vivo, allowing wireless transdermal transmission and long-lasting functionality in vivo. The ability to monitor glucose concentrations in vivo over the long term enables the sensors to be implanted and replaced less often, thereby bringing CGM closer to practical implementation. However, the full potential of long-term in vivo glucose monitoring has yet to be realized because current fluorescence-based sensors cannot remain at an implantation site and respond to blood glucose concentrations over an extended period. Here, we present a long-term in vivo glucose monitoring method using glucose-responsive fluorescent hydrogel fibers. We fabricated glucose-responsive fluorescent hydrogels in a fibrous structure because this structure enables the sensors to remain at the implantation site for a long period. Moreover, these fibers allow easy control of the amount of fluorescent sensors implanted, simply by cutting the fibers to the desired length, and facilitate sensor removal from the implantation site after use. We found that the polyethylene glycol (PEG)-bonded polyacrylamide (PAM) hydrogel fibers reduced inflammation compared with PAM hydrogel fibers, transdermally glowed, and continuously responded to blood glucose concentration changes for up to 140 days, showing their potential application for long-term in vivo continuous glucose monitoring. PMID:21808049

Heo, Yun Jung; Shibata, Hideaki; Okitsu, Teru; Kawanishi, Tetsuro; Takeuchi, Shoji

2011-08-16

331

Long Fluorescence Lifetime Molecular Probes Based on Near Infrared Pyrrolopyrrole Cyanine Fluorophores for In Vivo Imaging  

E-print Network

Long Fluorescence Lifetime Molecular Probes Based on Near Infrared Pyrrolopyrrole Cyanine of organic molecules provide a new reporting strategy for molecular imaging in the near infrared (NIR of near-infrared (NIR) fluorescent molecular probes have been developed for in vivo imaging applications

Larson-Prior, Linda

332

SQUID-Based Microtesla MRI for In Vivo Relaxometry of the Human Brain  

Microsoft Academic Search

SQUID-based MRI (magnetic resonance imaging) at microtesla fields has developed significantly over the past few years. Here we describe application of this method for magnetic relaxation measurements in the living human brain. We report values of the longitudinal relaxation time T1 for brain tissues, measured in vivo for the first time at microtesla fields. The experiments were performed at 46

Vadim S. Zotev; Andrei N. Matlashov; Igor M. Savukov; Tuba Owens; Petr L. Volegov; John J. Gomez; Michelle A. Espy

2009-01-01

333

Intracellular and Computational Characterization of the Intracortical Inhibitory Control of Synchronized Thalamic Inputs In Vivo  

E-print Network

inputs in vivo. J. Neuro- On the other hand, topical application of penicillin on physiol. 78: 335 to the hypothesisdles or following thalamic stimulation; 2) reversed IPSPs with that, in the penicillin epilepsy model the penicillin studies would be that during spindles, thalamic on reconstructed pyramidal cells constrained

Destexhe, Alain

334

In vivo molecular-genetic imaging: multi-modality nuclear and optical combinations  

Microsoft Academic Search

Multi-modality, noninvasive in vivo imaging is increasingly being used in molecular-genetic studies and will soon become the standard approach for reporter gene imaging studies in small animals. The coupling of nuclear and optical reporter genes, as described here, represents only the beginning of a far wider application of this technology in the future. Optical imaging and optical reporter systems are

Ronald G. Blasberg

2003-01-01

335

REVIEW ARTICLE: Nuclear-based techniques for the in vivo study of human body composition  

Microsoft Academic Search

A variety of nuclear-based techniques for the in vivo study of human body decomposition is now available for clinical diagnosis and research, and the number of centres where such work is performed is likely to grow substantially in the next few years. Their most important applications at present are in the measurement of bone mineral mass (calcium), body protein (nitrogen)

S. H. Cohn; R. M. Parr

1985-01-01

336

Nuclear-based techniques for the in vivo study of human body composition  

Microsoft Academic Search

A variety of nuclear-based techniques for the in vivo study of human body decomposition is now available for clinical diagnosis and research, and the number of centres where such work is performed is likely to grow substantially in the next few years. Their most important applications at present are in the measurement of bone mineral mass (calcium), body protein (nitrogen)

S H Cohn; R M Parr

1985-01-01

337

In vivo photoacoustic mapping of lymphatic systems with plasmon-resonant Chulhong Kim,xac  

E-print Network

In vivo photoacoustic mapping of lymphatic systems with plasmon-resonant nanostars Chulhong Kim, with direct application toward lymphangiography. Noninvasive medical imaging systems have been widely used://www.nanospectra.com). From a clinical perspective, conventional US array systems can be easily adapted to perform both PA

Wang, Lihong

338

Psychological Stress Exerts an Adjuvant Effect on Skin Dendritic Cell Functions In Vivo1  

Microsoft Academic Search

Psychological stress affects the pathophysiology of infectious, inflammatory, and autoimmune diseases. However, the mechanisms by which stress could modulate immune responses in vivo are poorly understood. In this study, we report that application of a psychological stress before immunization exerts an adjuvant effect on dendritic cell (DC), resulting in increased primary and memory Ag-specific T cell immune responses. Acute stress

Pierre Saint-Mezard; Cyril Chavagnac; Sophie Bosset; Marius Ionescu; Eric Peyron; Dominique Kaiserlian; Jean-Francois Nicolas; Frederic Berard

2003-01-01

339

In Vivo Gene Therapy of Hemophilia B: Sustained Partial Correction in Factor IX-Deficient Dogs  

Microsoft Academic Search

The liver represents a model organ for gene therapy. A method has been developed for hepatic gene transfer in vivo by the direct infusion of recombinant retroviral vectors into the portal vasculature, which results in the persistent expression of exogenous genes. To determine if these technologies are applicable for the treatment of hemophilia B patients, preclinical efficacy studies were done

Mark A. Kay; Steven Rothenberg; Charles N. Landen; Dwight A. Bellinger; Frances Leland; Carol Toman; Milton Finegold; Arthur R. Thompson; M. S. Read; Kenneth M. Brinkhous; Savio L. C. Woo

1993-01-01

340

Using a priori knowledge to classify in vivo images of the lung  

E-print Network

Using a priori knowledge to classify in vivo images of the lung Chesner D´esir1 , Caroline perspectives for this very challenging medical application. 1 Introduction The lungs are the essential, that includes the trachea, bronchi, and bronchioles, and (ii) the gas-exchange region, or lung parenchyma, made

Paris-Sud XI, Université de

341

Quantitative Evaluation of Liver-Specific Promoters From Retroviral Vectors After In Vivo Transduction of Hepatocytes  

E-print Network

Quantitative Evaluation of Liver-Specific Promoters From Retroviral Vectors After In Vivo of inherited blood diseases such ashemophilia or thrombophi- lia. Although liver-directed retroviral its clinical application, We reasoned that the insertion of liver-specific promoters into retroviral

Ponder, Katherine P.

342

COMPARABILITY OF IN VITRO AND IN VIVO METHODS FOR THE DETERMINATION OF ALTERATIONS IN DRUG METABOLISM  

EPA Science Inventory

The article reviews the use of model substrates to assess the capacity of the liver to metabolize xenobiotics via the myriad of drug metabolizing pathways available to it. The applicability of model compounds to act as predictors of in vivo drug metabolism in man and animals was ...

343

Ginkgo biloba extract EGb ® 761 increases endothelial nitric oxide production in vitro and in vivo  

Microsoft Academic Search

.  Beneficial effects of Ginkgo biloba on peripheral arterial occlusive disease have been repeatedly shown in clinical trials, especially after use of EGb 761, a standardized special extract. Since the underlying mechanisms are widely unknown, we aimed to elucidate the molecular\\u000a basis on which EGb 761 protects against endothelial dysfunction in vitro and in vivo. Application of therapeutically feasible doses of

A. Koltermann; A. Hartkorn; E. Koch; R. Fürst; A. M. Vollmar; S. Zahler

2007-01-01

344

Engineering intracellular active transport systems as in vivo biomolecular tools.  

SciTech Connect

Active transport systems provide essential functions in terms of cell physiology and metastasis. These systems, however, are also co-opted by invading viruses, enabling directed transport of the virus to and from the cell's nucleus (i.e., the site of virus replication). Based on this concept, fundamentally new approaches for interrogating and manipulating the inner workings of living cells may be achievable by co-opting Nature's active transport systems as an in vivo biomolecular tool. The overall goal of this project was to investigate the ability to engineer kinesin-based transport systems for in vivo applications, specifically the collection of effector proteins (e.g., transcriptional regulators) within single cells. In the first part of this project, a chimeric fusion protein consisting of kinesin and a single chain variable fragment (scFv) of an antibody was successfully produced through a recombinant expression system. The kinesin-scFv retained both catalytic and antigenic functionality, enabling selective capture and transport of target antigens. The incorporation of a rabbit IgG-specific scFv into the kinesin established a generalized system for functionalizing kinesin with a wide range of target-selective antibodies raised in rabbits. The second objective was to develop methods of isolating the intact microtubule network from live cells as a platform for evaluating kinesin-based transport within the cytoskeletal architecture of a cell. Successful isolation of intact microtubule networks from two distinct cell types was demonstrated using glutaraldehyde and methanol fixation methods. This work provides a platform for inferring the ability of kinesin-scFv to function in vivo, and may also serve as a three-dimensional scaffold for evaluating and exploiting kinesin-based transport for nanotechnological applications. Overall, the technology developed in this project represents a first-step in engineering active transport system for in vivo applications. Further development could potentially enable selective capture of intracellular antigens, targeted delivery of therapeutic agents, or disruption of the transport systems and consequently the infection and pathogenesis cycle of biothreat agents.

Bachand, George David; Carroll-Portillo, Amanda

2006-11-01

345

Pharmaceutical applications of chitosan  

Microsoft Academic Search

Considerable research efforts have been directed towards the development of safe and efficient chitosan-based drug delivery systems. In this review, the authors outline the major new approaches to the pharmaceutical applications of chitosan and discuss its mechanisms of action in various in vitro and in vivo models.

Valérie Dodane; Vinod D Vilivalam

1998-01-01

346

Development of the in vivo flow cytometer  

E-print Network

An in vivo flow cytometer has been developed that allows the real-time detection and quantification of circulating cells containing fluorescent proteins or labeled with fluorochrome molecules in live animals, without the ...

Novak, John P. (John Peter), 1957-

2004-01-01

347

In Vivo Imaging of Tissue Physiological Function  

Cancer.gov

The National Cancer Institute's Radiation Biology Branch is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize methods for in vivo imaging.

348

High-throughput in vivo vertebrate screening  

E-print Network

We demonstrate a high-throughput platform for cellular-resolution in vivo chemical and genetic screens on zebrafish larvae. The system automatically loads zebrafish from reservoirs or multiwell plates, and positions and ...

Pardo-Martin, Carlos

349

Increased in vivo stability and functional lifetime of an implantable glucose sensor through platinum catalysis.  

PubMed

Understanding and improving in vivo materials related to signal stability and preservation for active chemical sensor and biosensor transduction systems is critical in achieving implantable medical sensors for long-term in vivo applications. During human in vivo clinical testing of an implantable glucose sensor based on a glucose sensitive hydrogel, post-explant analysis showed that the boronate recognition element had been oxidized from the fluorescent indicator, causing a rapid loss of signal within hours after implant. Additional wet-bench analytical evidence and reproduction in vitro suggests reactive oxygen species, particularly hydrogen peroxide (H2O2), stemming from natural inflammatory response to the material, to be the cause of the observed oxidative de-boronation. A 3-nm thick deposition of metallic platinum (Pt) placed by plasma sputtering onto the porous surface of the hydrogel, showed immediate protection from sensor signal loss due to oxidation both in vitro and in vivo, greatly extending the useful lifetime of the implantable glucose sensor from 1 day to an expected ?6 months. This finding may represent a new strategy to protect an implanted material and/or device from in vivo oxidative damage, leading to much improved overall stability and reliability for long-term applications. PMID:23071075

Colvin, Arthur E; Jiang, Hui

2013-05-01

350

The potential of photoacoustic microscopy as a tool to characterize the in vivo degradation of surgical sutures.  

PubMed

The ex vivo and in vivo imaging, and quantitative characterization of the degradation of surgical sutures (?500 ?m diameter) up to ?1cm depth is demonstrated using a custom dark-field photo-acoustic microscope (PAM). A practical algorithm is developed to accurately measure the suture diameter during the degradation process. The results from tissue simulating phantoms and mice are compared to ex vivo measurements with an optical microscope demonstrating that PAM has a great deal of potential to characterize the degradation process of surgical sutures. The implications of this work for industrial applications are discussed. PMID:25136508

Aguirre, Juan; Morales-Dalmau, Jordi; Funk, Lutz; Jara, Francesc; Turon, Pau; Durduran, Turgut

2014-08-01

351

The potential of photoacoustic microscopy as a tool to characterize the in vivo degradation of surgical sutures  

PubMed Central

The ex vivo and in vivo imaging, and quantitative characterization of the degradation of surgical sutures (?500 ?m diameter) up to ?1cm depth is demonstrated using a custom dark-field photo-acoustic microscope (PAM). A practical algorithm is developed to accurately measure the suture diameter during the degradation process. The results from tissue simulating phantoms and mice are compared to ex vivo measurements with an optical microscope demonstrating that PAM has a great deal of potential to characterize the degradation process of surgical sutures. The implications of this work for industrial applications are discussed. PMID:25136508

Aguirre, Juan; Morales-Dalmau, Jordi; Funk, Lutz; Jara, Francesc; Turon, Pau; Durduran, Turgut

2014-01-01

352

Pumilio-based RNA in vivo imaging.  

PubMed

Subcellular, sequence-specific detection of RNA in vivo is a powerful tool to study the macromolecular transport that occurs through plasmodesmata. The RNA-binding domain of Pumilio proteins can be engineered to bind RNA sequences of choice and fused to fluorescent proteins for RNA imaging. This chapter describes the construction of a Pumilio-based imaging system to track the RNA of Tobacco mosaic virus in vivo, and practical aspects of RNA live-cell imaging. PMID:25287212

Tilsner, Jens

2015-01-01

353

In Vivo Response to Dynamic Hyaluronic Acid Hydrogels  

PubMed Central

Tissue-specific elasticity arises in part from developmental changes in extracellular matrix over time, e.g. ~ 10-fold myocardial stiffening in the chicken embryo. When this time-dependent stiffening is mimicked in vitro with thiolated hyaluronic acid (HA-SH) hydrogels, improved cardiomyocyte maturation has been observed. However, host interactions, matrix polymerization, and stiffening kinetics remain uncertain in vivo, and each plays a critical role in therapeutic applications using HA-SH. Hematological and histological analysis of subcutaneously injected HA-SH hydrogels showed minimal systemic immune response and host cell infiltration. Most importantly, subcutaneously injected HA-SH hydrogels exhibited time dependent porosity and stiffness changes at a rate similar to hydrogels polymerized in vitro. When injected intramyocardially, host cells begin to actively degrade HA-SH hydrogels within 1-week post-injection, continuing this process while producing matrix to nearly replace the hydrogel within 1 month post-injection. While non-thiolated HA did not degrade after injection into the myocardium, it also did not elicit an immune response, unlike HA-SH, where visible granulomas and macrophage infiltration were present at 1 month post-injection, likely due to reactive thiol groups. Altogether, these data suggest that the HA-SH hydrogel responds appropriately in a less vascularized niche and stiffens as had been demonstrated in vitro, but in more vascularized tissues, in vivo applicability appears limited. PMID:23523533

Young, Jennifer L.; Tuler, Jeremy; Braden, Rebecca; Schüp-Magoffin, Pamela; Schaefer, Jacquelyn; Kretchmer, Kyle; Christman, Karen L.; Engler, Adam J.

2013-01-01

354

Quantum Dots for Live Cell and In Vivo Imaging  

PubMed Central

In the past few decades, technology has made immeasurable strides to enable visualization, identification, and quantitation in biological systems. Many of these technological advancements are occurring on the nanometer scale, where multiple scientific disciplines are combining to create new materials with enhanced properties. The integration of inorganic synthetic methods with a size reduction to the nano-scale has lead to the creation of a new class of optical reporters, called quantum dots. These semiconductor quantum dot nanocrystals have emerged as an alternative to organic dyes and fluorescent proteins, and are brighter and more stable against photobleaching than standard fluorescent indicators. Quantum dots have tunable optical properties that have proved useful in a wide range of applications from multiplexed analysis such as DNA detection and cell sorting and tracking, to most recently demonstrating promise for in vivo imaging and diagnostics. This review provides an in-depth discussion of past, present, and future trends in quantum dot use with an emphasis on in vivo imaging and its related applications. PMID:19333416

Walling, Maureen A; Novak, Jennifer A; Shepard, Jason R. E

2009-01-01

355

Synergy between in situ cryoablation and TLR9 stimulation results in a highly effective in vivo dendritic cell vaccine  

Microsoft Academic Search

Dendritic cells (DC) are professional antigen-presenting cells that play a pivotal role in the induction of immunity. Ex vivo-generated, tumor antigen-loaded mature DC are currently exploited as cancer vaccines in clinical studies. However, antigen loading and maturation of DC directly in vivo would greatly facilitate the application of DC-based vaccines. We have previously shown that in situ tumor destruction by

M. H. M. G. M. den Brok; R. P. M. Sutmuller; S. Nierkens; E. J. Bennink; L. W. J. Toonen; C. G. Figdor; T. J. M. Ruers; G. J. Adema

2006-01-01

356

Blood flow and blood velocity measurement in vivo by electromagnetic induction  

Microsoft Academic Search

The application of electromagnetic induction to the measurement of blood flow and blood velocityin vivo is reviewed. The electronics requirements are discussed and the associated problems are surveyed. An account is given of\\u000a Bevir's virtual-current theory and its application to various flow and velocity measuring devices. The devices at present\\u000a known to be in use or under development are reviewed

D. G. Wyatt

1984-01-01

357

Ex Vivo and In Vivo Models for Endoscopic Submucosal Dissection Training  

PubMed Central

Endoscopic submucosal dissection is a technically challenging but highly effective technique for the treatment of well selected early neoplasms in the digestive tract. Although it is frequently performed in East Asian countries, the Western world has not adopted this technique yet, probably due in part to the difficulty to learn it. Ex vivo and in vivo animal models are invaluable tools to overcome at least the beginning of the learning curve, although the initial step is the acquisition of basic knowledge about early diagnosis of neoplasias, and observing real procedures in expert centers. The practical issues, advantages, and disadvantages of the ex vivo and in vivo models are discussed. PMID:23251881

Gonzalez, Nicolas; Arnau, Maria Rosa

2012-01-01

358

Endodontic photodynamic therapy ex vivo  

PubMed Central

Objective To evaluate the anti-microbial effects of photodynamic therapy (PDT) on infected human teeth ex vivo. Materials and Methods Fifty-two freshly extracted teeth with pulpal necrosis and associated periradicular radiolucencies were obtained from 34 subjects. Twenty-six teeth with 49 canals received chemomechanical debridement (CMD) with 6% NaOCl and twenty-six teeth with 52 canals received CMD plus PDT. For PDT, root canal systems were incubated with methylene blue (MB) at concentration of 50 µg/ml for 5 minutes followed by exposure to red light at 665 nm with an energy fluence of 30 J/cm2. The contents of root canals were sampled by flushing the canals at baseline and following CMD alone or CMD+PDT and were serially diluted and cultured on blood agar. Survival fractions were calculated by counting colony-forming units (CFU). Partial characterization of root canal species at baseline and following CMD alone or CMD+PDT was performed using DNA probes to a panel of 39 endodontic species in the checkerboard assay. Results The Mantel-Haenszel chi-square test for treatment effects demonstrated the better performance of CMD+PDT over CMD (P=0.026). CMD+PDT significantly reduced the frequency of positive canals relative to CMD alone (P=0.0003). Following CMD+PDT, 45 of 52 canals (86.5%) had no CFU as compared to 24 of 49 canals (49%) treated with CMD (canal flush samples). The CFU reductions were similar when teeth or canals were treated as independent entities. Post-treatment detection levels for all species were markedly lower for canals treated by CMD+PDT than were for those treated by CMD alone. Bacterial species within dentinal tubules were detected in 17/22 (77.3%) and 15/29 (51.7%) of canals in the CMD and CMD+PDT group, respectively (P= 0.034). Conclusion Data indicate that PDT significantly reduces residual bacteria within the root canal system, and that PDT, if further enhanced by technical improvements, holds substantial promise as an adjunct to CMD. PMID:21238805

Ng, Raymond; Singh, Fiza; Papamanou, Despoina A.; Song, Xiaoqing; Patel, Chitrang; Holewa, Colleen; Patel, Niraj; Klepac-Ceraj, Vanja; Fontana, Carla R.; Kent, Ralph; Pagonis, Tom C.; Stashenko, Philip P.; Soukos, Nikolaos S.

2010-01-01

359

High-resolution optical coherence microscopy for high-speed, in vivo cellular imaging  

NASA Astrophysics Data System (ADS)

Optical coherence microscopy (OCM) is demonstrated with a high-speed, broadband, reflective-grating phase modulator and a femtosecond Ti:Al2O3 laser. The novel system design permits high-resolution OCM imaging in a new operating regime in which a short coherence gate is used to relax the requirement for high-numerical-aperture confocal axial sectioning. In vivo cellular imaging is demonstrated in the Xenopus laevis tadpole and in human skin with a 3-?m coherence gate and a 30-?m confocal gate. The ability to achieve cellular imaging with a lower numerical aperture should facilitate the development of miniaturized probes for in vivo imaging applications.

Aguirre, A. D.; Hsiung, P.; Ko, T. H.; Hartl, I.; Fujimoto, J. G.

2003-11-01

360

Direct determination of the redox status of cysteine residues in proteins in vivo.  

PubMed

The redox states of proteins in cells are key factors in many cellular processes. To determine the redox status of cysteinyl thiol groups in proteins in vivo, we developed a new maleimide reagent, a photocleavable maleimide-conjugated single stranded DNA (DNA-PCMal). The DNA moiety of DNA-PCMal is easily removed by UV-irradiation, allowing DNA-PCMal to be used in Western blotting applications. Thereby the state of thiol groups in intracellular proteins can be directly evaluated. This new maleimide compound can provide information concerning redox proteins in vivo, which is important for our understanding of redox networks in the cell. PMID:25436431

Hara, Satoshi; Tatenaka, Yuki; Ohuchi, Yuya; Hisabori, Toru

2015-01-01

361

Extradiscal ultrasound thermal therapy (ExDUSTT): evaluation in ex vivo and in vivo spine models (Invited Paper)  

NASA Astrophysics Data System (ADS)

The application of heat to intervertebral discs is being clinically investigated for the treatment of discogenic back pain. The purpose of this study was to develop and test the feasibility of small ultrasound applicators that can be endoscopically placed adjacent to the disc, and deliver heating energy into the disc without puncturing the annular wall. Prototype devices were fabricated using curvilinear transducers (2.5-3.5 mm wide x 10 mm long, 5.4 - 6.5 MHz) that produce a narrow penetrating beam extending along the length of the ultrasound element. The transducer was affixed to either a flexible or rigid delivery catheter, and enclosed within an asymmetric coupling balloon with water-cooling flow. Bench measurements demonstrated 35-60% acoustic efficiencies, high-power output capabilities, and lightly focused beam patterns. The heating characteristics of these devices were evaluated with ex vivo and in vivo experiments within lumbar and cervical spine segments from sheep models and human cadaveric spine. The applicators were positioned adjacent to the annular wall of the surgically exposed discs. Ultrasound energy was focused directly into the disc to avoid heating the vertebral bodies. Multi-point thermocouple probes were placed throughout the disc to characterize the resultant temperature distributions. These studies demonstrated that ultrasound energy from these applicators penetrated the annular wall of the disc, and produced thermal coagulative temperatures of >60-65°C as far as 10 mm into the tissue. This study also showed that lower power levels and temperatures delivered for 10 minutes can generate a cytotoxic thermal dose of t43°C >240 min penetrating 5-10 mm from the annular wall.

Diederich, Chris J.; Kinsey, Adam; Nau, William H.; Shu, Richard; Lotz, Jeffrey C.

2005-04-01

362

In vivo mitochondrial oxygen tension measured by a delayed fluorescence lifetime technique.  

PubMed

Mitochondrial oxygen tension (mitoPO(2)) is a key parameter for cellular function, which is considered to be affected under various pathophysiological circumstances. Although many techniques for assessing in vivo oxygenation are available, no technique for measuring mitoPO(2) in vivo exists. Here we report in vivo measurement of mitoPO(2) and the recovery of mitoPO(2) histograms in rat liver by a novel optical technique under normal and pathological circumstances. The technique is based on oxygen-dependent quenching of the delayed fluorescence lifetime of protoporphyrin IX. Application of 5-aminolevulinic acid enhanced mitochondrial protoporphyrin IX levels and induced oxygen-dependent delayed fluorescence in various tissues, without affecting mitochondrial respiration. Using fluorescence microscopy, we demonstrate in isolated hepatocytes that the signal is of mitochondrial origin. The delayed fluorescence lifetime was calibrated in isolated hepatocytes and isolated perfused livers. Ultimately, the technique was applied to measure mitoPO(2) in rat liver in vivo. The results demonstrate mitoPO(2) values of approximately 30-40 mmHg. mitoPO(2) was highly sensitive to small changes in inspired oxygen concentration around atmospheric oxygen level. Ischemia-reperfusion interventions showed altered mitoPO(2) distribution, which flattened overall compared to baseline conditions. The reported technology is scalable from microscopic to macroscopic applications, and its reliance on an endogenous compound greatly enhances its potential field of applications. PMID:18641065

Mik, Egbert G; Johannes, Tanja; Zuurbier, Coert J; Heinen, Andre; Houben-Weerts, Judith H P M; Balestra, Gianmarco M; Stap, Jan; Beek, Johan F; Ince, Can

2008-10-01

363

In Vivo Mitochondrial Oxygen Tension Measured by a Delayed Fluorescence Lifetime Technique  

PubMed Central

Mitochondrial oxygen tension (mitoPO2) is a key parameter for cellular function, which is considered to be affected under various pathophysiological circumstances. Although many techniques for assessing in vivo oxygenation are available, no technique for measuring mitoPO2 in vivo exists. Here we report in vivo measurement of mitoPO2 and the recovery of mitoPO2 histograms in rat liver by a novel optical technique under normal and pathological circumstances. The technique is based on oxygen-dependent quenching of the delayed fluorescence lifetime of protoporphyrin IX. Application of 5-aminolevulinic acid enhanced mitochondrial protoporphyrin IX levels and induced oxygen-dependent delayed fluorescence in various tissues, without affecting mitochondrial respiration. Using fluorescence microscopy, we demonstrate in isolated hepatocytes that the signal is of mitochondrial origin. The delayed fluorescence lifetime was calibrated in isolated hepatocytes and isolated perfused livers. Ultimately, the technique was applied to measure mitoPO2 in rat liver in vivo. The results demonstrate mitoPO2 values of ?30–40 mmHg. mitoPO2 was highly sensitive to small changes in inspired oxygen concentration around atmospheric oxygen level. Ischemia-reperfusion interventions showed altered mitoPO2 distribution, which flattened overall compared to baseline conditions. The reported technology is scalable from microscopic to macroscopic applications, and its reliance on an endogenous compound greatly enhances its potential field of applications. PMID:18641065

Mik, Egbert G.; Johannes, Tanja; Zuurbier, Coert J.; Heinen, Andre; Houben-Weerts, Judith H. P. M.; Balestra, Gianmarco M.; Stap, Jan; Beek, Johan F.; Ince, Can

2008-01-01

364

In vivo studies of opiate receptors  

SciTech Connect

To study opiate receptors noninvasively in vivo using positron emission tomography, techniques for preferentially labeling opiate receptors in vivo can be used. The rate at which receptor-bound ligand clears from the brain in vivo can be predicted by measuring the equilibrium dissociation constant (KD) at 37 degrees C in the presence of 100 mM sodium chloride and 100 microM guanyl-5'-imidodiphosphate, the drug distribution coefficient, and the molecular weight. A suitable ligand for labeling opiate receptors in vivo is diprenorphine, which binds to mu, delta, and kappa receptors with approximately equal affinity in vitro. However, in vivo diprenorphine may bind predominantly to one opiate receptor subtype, possibly the mu receptor. To predict the affinity for binding to the opiate receptor, a Hansch correlation was determined between the 50% inhibitory concentration for a series of halogen-substituted fentanyl analogs and electronic, lipophilic, and steric parameters. Radiochemical methods for the synthesis of carbon-11-labeled diprenorphine and lofentanil are presented.

Frost, J.J.; Dannals, R.F.; Duelfer, T.; Burns, H.D.; Ravert, H.T.; Langstroem, B.; Balasubramanian, V.; Wagner, H.N. Jr.

1984-01-01

365

The challenges facing block copolymer micelles for cancer therapy: In vivo barriers and clinical translation.  

PubMed

The application of block copolymer micelles (BCMs) in oncology has benefitted from advances in polymer chemistry, drug formulation and delivery as well as in vitro and in vivo biological models. While great strides have been made in each of these individual areas, there remains some disappointment overall, citing, in particular, the absence of more BCM formulations in clinical evaluation and practice. In this review, we aim to provide an overview of the challenges presented by in vivo systems to the effective design and development of BCMs. In particular, the barriers posed by systemic administration and tumor properties are examined. The impact of critical features, such as the size, stability and functionalization of BCMs is discussed, while key pre-clinical endpoints and models are critiqued. Given clinical considerations, we present this work as a means to stimulate a renewed focus on the unique chemical versatility bestowed by BCMs and a measured grasp of representative in vitro and in vivo models. PMID:25308250

Eetezadi, Sina; Ekdawi, Sandra N; Allen, Christine

2014-10-13

366

In vivo assessment of cancerous tumors using boron doped diamond microelectrode  

PubMed Central

The in vitro and in vivo electrochemical detection of the reduced form of glutathione (L-?-glutamyl-L-cysteinyl-glycine, GSH) using boron doped diamond (BDD) microelectrode for potential application in the assessment of cancerous tumors is presented. Accurate calibration curve for the determination of GSH could be obtained by the in vitro electrochemical measurements. Additionally, it was shown that it was possible to separate the detection of GSH from the oxidized form of glutathione (GSSG) using chronoamperometry measurements. In vivo GSH detection measurements have been performed in human cancer cells inoculated in immunodeficient mice. These measurements have shown that the difference of GSH level between cancerous and normal tissues can be detected. Moreover, GSH detection measurements carried out before and after X-ray irradiation have proved that it is possible to assess in vivo the decrease in GSH concentration in the tumor after a specific treatment. PMID:23198091

Fierro, Stéphane; Yoshikawa, Momoko; Nagano, Osamu; Yoshimi, Kenji; Saya, Hideyuki; Einaga, Yasuaki

2012-01-01

367

Non-selective action of 4-hydroxyanisole on melanoma cells in vivo.  

PubMed

In order to clarify the role of tyrosinase (E.C. 1.14.18.1) in the cytotoxicity of 4-hydroxyanisole (4HA) in vivo, we have compared the therapeutic effects of 4HA on the B16 melanoma and Harding-Passey melanoma, which differ significantly in their tyrosinase content. The observed therapeutic effects are moderate and similar in both tumors. Therefore, there is no evidence for an increase of the cytotoxic effect of 4HA by tyrosinase in vivo. Application of 4HA to mice carrying B16 melanoma and Harding-Passey melanoma results in an inhibition of [3H]-TdR incorporation into melanoma DNA as well as into DNA of liver, intestine, kidney, and spleen. There is no selective activity on melanoma cells by 4HA in vivo. Therefore, in the therapy of human melanoma by 4HA, side effects on normal tissues cannot be excluded. PMID:2116000

Schwabe, K; Fichtner, I; Tschiersch, B

1990-01-01

368

Real time monitoring of superoxide dynamics in vivo through fluorescent proteins using a sensitive fiber probe  

NASA Astrophysics Data System (ADS)

Superoxide anion is the primary oxygen free radical generated in mitochondria that causes intracellular oxidative stress. The lack of a method to directly monitor superoxide concentration in vivo in real time has severely hindered our understanding on its pathophysiology. We made transgenic zebrafish to specifically express fluorescent proteins, which are recently developed as reversible superoxide-specific indicators, in the liver. A fiber-optic fluorescent probe was used to noninvasively monitor superoxide generation in the liver in real time. The fish were placed in microfluidic channels for manipulation and reagents administration. Several superoxide-inducing and scavenging reagents were administrated onto the fish to investigate their effects on superoxide anion balancing. The biochemical dynamics of superoxide due to the application reagents were revealed in the transient behaviors of fluorescence time courses. With the ability to monitor superoxide dynamics in vivo in real time, this method can be used as an in vivo pharmaceutical screening platform.

Chang, Yu-Chung; Ken, Chuian-Fu; Hsu, Che-Wei; Liu, Ya-Ging

2014-03-01

369

In Vivo Gene Therapy of Hemophilia B: Sustained Partial Correction in Factor IX-Deficient Dogs  

NASA Astrophysics Data System (ADS)

The liver represents a model organ for gene therapy. A method has been developed for hepatic gene transfer in vivo by the direct infusion of recombinant retroviral vectors into the portal vasculature, which results in the persistent expression of exogenous genes. To determine if these technologies are applicable for the treatment of hemophilia B patients, preclinical efficacy studies were done in a hemophilia B dog model. When the canine factor IX complementary DNA was transduced directly into the hepatocytes of affected dogs in vivo, the animals constitutively expressed low levels of canine factor IX for more than 5 months. Persistent expression of the clotting. factor resulted in reductions of whole blood clotting and partial thromboplastin times of the treated animals. Thus, long-term treatment of hemophilia B patients may be feasible by direct hepatic gene therapy in vivo.

Kay, Mark A.; Rothenberg, Steven; Landen, Charles N.; Bellinger, Dwight A.; Leland, Frances; Toman, Carol; Finegold, Milton; Thompson, Arthur R.; Read, M. S.; Brinkhous, Kenneth M.; Woo, Savio L. C.

1993-10-01

370

Combining pharmacology and whole-cell patch recording from CNS neurons, in vivo  

PubMed Central

Whole-cell patch neurophysiology and pharmacological manipulations have provided unprecedented insight into the functions of central neurons, but their combined use has been largely restricted to in vitro preparations. We describe a method for performing whole-cell patch recording and focal application of pharmacological agents in vivo. A key feature of this technique involves iontophoresis of glutamate to establish proximity of drug and recording pipettes. We show data from iontophoresis of glutamate during extracellular and whole-cell recordings made in vivo from auditory neurons in the midbrain of the leopard frog, Rana pipiens, and the effects of blocking GABAA receptors while making a whole-cell recording. This methodology should accelerate our understanding of the roles of particular neurotransmitter systems in normal and pathological conditions, and facilitate investigation of the in vivo effects of drugs and the mechanisms underlying computations. PMID:23261772

Rose, Gary J.; Alluri, Rishi K.; Vasquez-Opazo, Gustavo A.; Odom, Stephen E.; Graham, Jalina A.; Leary, Christopher J.

2013-01-01

371

In vivo assessment of cancerous tumors using boron doped diamond microelectrode  

NASA Astrophysics Data System (ADS)

The in vitro and in vivo electrochemical detection of the reduced form of glutathione (L-?-glutamyl-L-cysteinyl-glycine, GSH) using boron doped diamond (BDD) microelectrode for potential application in the assessment of cancerous tumors is presented. Accurate calibration curve for the determination of GSH could be obtained by the in vitro electrochemical measurements. Additionally, it was shown that it was possible to separate the detection of GSH from the oxidized form of glutathione (GSSG) using chronoamperometry measurements. In vivo GSH detection measurements have been performed in human cancer cells inoculated in immunodeficient mice. These measurements have shown that the difference of GSH level between cancerous and normal tissues can be detected. Moreover, GSH detection measurements carried out before and after X-ray irradiation have proved that it is possible to assess in vivo the decrease in GSH concentration in the tumor after a specific treatment.

Fierro, Stéphane; Yoshikawa, Momoko; Nagano, Osamu; Yoshimi, Kenji; Saya, Hideyuki; Einaga, Yasuaki

2012-11-01

372

In Vivo Imaging of Human Cone Photoreceptor Inner Segments  

PubMed Central

Purpose. An often overlooked prerequisite to cone photoreceptor gene therapy development is residual photoreceptor structure that can be rescued. While advances in adaptive optics (AO) retinal imaging have recently enabled direct visualization of individual cone and rod photoreceptors in the living human retina, these techniques largely detect strongly directionally-backscattered (waveguided) light from normal intact photoreceptors. This represents a major limitation in using existing AO imaging to quantify structure of remnant cones in degenerating retina. Methods. Photoreceptor inner segment structure was assessed with a novel AO scanning light ophthalmoscopy (AOSLO) differential phase technique, that we termed nonconfocal split-detector, in two healthy subjects and four subjects with achromatopsia. Ex vivo preparations of five healthy donor eyes were analyzed for comparison of inner segment diameter to that measured in vivo with split-detector AOSLO. Results. Nonconfocal split-detector AOSLO reveals the photoreceptor inner segment with or without the presence of a waveguiding outer segment. The diameter of inner segments measured in vivo is in good agreement with histology. A substantial number of foveal and parafoveal cone photoreceptors with apparently intact inner segments were identified in patients with the inherited disease achromatopsia. Conclusions. The application of nonconfocal split-detector to emerging human gene therapy trials will improve the potential of therapeutic success, by identifying patients with sufficient retained photoreceptor structure to benefit the most from intervention. Additionally, split-detector imaging may be useful for studies of other retinal degenerations such as AMD, retinitis pigmentosa, and choroideremia where the outer segment is lost before the remainder of the photoreceptor cell. PMID:24906859

Scoles, Drew; Sulai, Yusufu N.; Langlo, Christopher S.; Fishman, Gerald A.; Curcio, Christine A.; Carroll, Joseph; Dubra, Alfredo

2014-01-01

373

In vivo safety evaluation of polyarginine coated magnetic nanovectors.  

PubMed

Safety and efficacy are of critical importance to any nanomaterial-based diagnostic and therapy. The innocuity and functionality of a nanomaterial in vivo is largely dependent on the physicochemical properties of the material, particularly its surface coating. Here, we evaluated the influence of polycationic coating on the efficacy, clearance organ uptake, and safety of magnetic nanovectors designed for siRNA delivery. Polyethylene glycol (PEG) coated superparamagnetic iron oxide nanoparticles (NPs) of 12 nm in core diameter were modified with a polycationic coating of either poly-l-arginine (pArg) or polyethylenimine (PEI) and further covalently functionalized with siRNA oligonucleotides. The produced NP-pArg-siRNA and NP-PEI-siRNA nanovectors were similar in hydrodynamic size (21 and 22 nm, respectively) but significantly differed in zeta potentials (+2.1 mV and +29.8 mV, respectively). Fluorescence quantification assays revealed that the NP-pArg-siRNA nanovector was 3-fold more potent than NP-PEI-siRNA in delivering siRNA and 1.8-fold more effective in gene silencing when tested in rat C6 glioblastoma cells. In vivo, both nanovector formulations were similarly taken up by the spleen and liver as determined by histopathological and hemopathological assays. However, PEI coated nanovectors elicited severe hemoincompatibility and damage to the liver and spleen, while pArg coated nanovectors were found to be safe and tolerable. Combined, our findings suggest that polycationic coatings of pArg were more effective and safer than commonly used PEI coatings for preparation of nanovectors. The NP-pArg-siRNA nanovector formulation developed here shows great potential for in vivo based biomedical applications. PMID:24099143

Veiseh, Omid; Kievit, Forrest M; Liu, Vicki; Fang, Chen; Stephen, Zachary R; Ellenbogen, Richard G; Zhang, Miqin

2013-11-01

374

In Vivo Ultrasonic Detection of Polyurea Crosslinked Silica Aerogel Implants  

PubMed Central

Background Polyurea crosslinked silica aerogels are highly porous, lightweight, and mechanically strong materials with great potential for in vivo applications. Recent in vivo and in vitro studies have demonstrated the biocompatibility of this type of aerogel. The highly porous nature of aerogels allows for exceptional thermal, electric, and acoustic insulating capabilities that can be taken advantage of for non-invasive external imaging techniques. Sound-based detection of implants is a low cost, non-invasive, portable, and rapid technique that is routinely used and readily available in major clinics and hospitals. Methodology In this study the first in vivo ultrasound response of polyurea crosslinked silica aerogel implants was investigated by means of a GE Medical Systems LogiQe diagnostic ultrasound machine with a linear array probe. Aerogel samples were inserted subcutaneously and sub-muscularly in a) fresh animal model and b) cadaveric human model for analysis. For comparison, samples of polydimethylsiloxane (PDMS) were also imaged under similar conditions as the aerogel samples. Conclusion/significance Polyurea crosslinked silica aerogel (X-Si aerogel) implants were easily identified when inserted in either of the regions in both fresh animal model and cadaveric model. The implant dimensions inferred from the images matched the actual size of the implants and no apparent damage was sustained by the X-Si aerogel implants as a result of the ultrasonic imaging process. The aerogel implants demonstrated hyperechoic behavior and significant posterior shadowing. Results obtained were compared with images acquired from the PDMS implants inserted at the same location. PMID:23799093

Sabri, Firouzeh; Sebelik, Merry E.; Meacham, Ryan; Boughter, John D.; Challis, Mitchell J.; Leventis, Nicholas

2013-01-01

375

In vivo safety evaluation of polyarginine coated magnetic nanovectors  

PubMed Central

Safety and efficacy are of critical importance to any nanomaterial-based diagnostic and therapy. The innocuity and functionality of a nanomaterial in vivo is largely dependent on the physicochemical properties of the material, particularly its surface coating. Here, we evaluated the influence of polycationic coating on the efficacy, clearance organ uptake, and safety of magnetic nanovectors designed for siRNA delivery. Polyethylene glycol (PEG) coated superparamagnetic iron oxide nanoparticles (NPs) of 12 nm in core diameter were modified with a polycationic coating of either poly-L-arginine (pArg) or polyethylenimine (PEI) and further covalently functionalized with siRNA oligonucleotides. The produced NP-pArg-siRNA and NP-PEI-siRNA nanovectors were similar in hydrodynamic size (21 nm and 22 nm, respectively), but significantly differed in zeta potentials (+2.1 mV and +29.8 mV, respectively). Fluorescence quantification assays revealed that the NP-pArg-siRNA nanovector was 3-fold more potent than NP-PEI-siRNA in delivering siRNA, and 1.8-fold more effective in gene silencing when tested in rat C6 glioblastoma cells. In vivo, both nanovector formulations were similarly taken up by the spleen and liver as determined by histopathological and hemopathological assays. However, PEI coated nanovectors elicited severe hemoincompatibility and damage to the liver and spleen while pArg coated nanovectors were found to be safe and tolerable. Combined, our findings suggest that polycationic coatings of pArg were more effective and safer than commonly used PEI coatings for preparation of nanovectors. The NP-pArg-siRNA nanovector formulation developed here shows great potential for in vivo based biomedical applications. PMID:24099143

Veiseh, Omid; Kievit, Forrest M.; Liu, Vicki; Fang, Chen; Stephen, Zachary R.; Ellenbogen, Richard G.; Zhang, Miqin

2013-01-01

376

In vivo imaging of rat cortical bone porosity by synchrotron phase contrast micro computed tomography  

NASA Astrophysics Data System (ADS)

Cortical bone is a dynamic tissue which undergoes adaptive and pathological changes throughout life. Direct longitudinal tracking of this remodeling process holds great promise for improving our understanding of bone development, maintenance and senescence. The application of in vivo micro-computed tomography (micro-CT) has enabled longitudinal tracking of trabecular bone microarchitecture with commercially available scanners generally operating in the 10–20?µm voxel range with absorbed doses reported between 0.5 and 1?Gy. Imaging of cortical bone microarchitecture (porosity) requires higher resolution and thus in vivo imaging of these structures has not been achieved due to excessive radiation dose. In this study we tested the hypothesis that synchrotron propagation phase contrast micro-CT can enable in vivo imaging of cortical porosity in rats at doses comparable to those currently employed for trabecular bone imaging. Synchrotron imaging experiments were conducted at the Canadian Light Source using the bending magnet beamline of the BioMedical Imaging and Therapy (BMIT) facility. Protocol optimization (propagation distance, projection number) was conducted ex vivo on rat (Sprague-Dawley) forelimbs with dose determined by ion chamber and lithium fluoride crystal thermoluminescent dosimeters. Comparative ex vivo imaging was performed using laboratory in vivo scanning systems, identifying a range of doses between 1.2–3.6?Gy for common protocols. A final in vivo synchrotron protocol involving a 2.5?Gy dose was implemented with live rats. The resulting images demonstrated improved delineation of cortical porosity through the improved edge enhancement effect of phase contrast, opening the door to novel experimental studies involving the longitudinal tracking of remodeling.

Pratt, I. V.; Belev, G.; Zhu, N.; Chapman, L. D.; Cooper, D. M. L.

2015-01-01

377

In vivo imaging of rat cortical bone porosity by synchrotron phase contrast micro computed tomography.  

PubMed

Cortical bone is a dynamic tissue which undergoes adaptive and pathological changes throughout life. Direct longitudinal tracking of this remodeling process holds great promise for improving our understanding of bone development, maintenance and senescence. The application of in vivo micro-computed tomography (micro-CT) has enabled longitudinal tracking of trabecular bone microarchitecture with commercially available scanners generally operating in the 10-20?µm voxel range with absorbed doses reported between 0.5 and 1?Gy. Imaging of cortical bone microarchitecture (porosity) requires higher resolution and thus in vivo imaging of these structures has not been achieved due to excessive radiation dose. In this study we tested the hypothesis that synchrotron propagation phase contrast micro-CT can enable in vivo imaging of cortical porosity in rats at doses comparable to those currently employed for trabecular bone imaging. Synchrotron imaging experiments were conducted at the Canadian Light Source using the bending magnet beamline of the BioMedical Imaging and Therapy (BMIT) facility. Protocol optimization (propagation distance, projection number) was conducted ex vivo on rat (Sprague-Dawley) forelimbs with dose determined by ion chamber and lithium fluoride crystal thermoluminescent dosimeters. Comparative ex vivo imaging was performed using laboratory in vivo scanning systems, identifying a range of doses between 1.2-3.6?Gy for common protocols. A final in vivo synchrotron protocol involving a 2.5?Gy dose was implemented with live rats. The resulting images demonstrated improved delineation of cortical porosity through the improved edge enhancement effect of phase contrast, opening the door to novel experimental studies involving the longitudinal tracking of remodeling. PMID:25489926

Pratt, I V; Belev, G; Zhu, N; Chapman, L D; Cooper, D M L

2015-01-01

378

Outer Hair Cell Electromotility in vivo  

NASA Astrophysics Data System (ADS)

The effectiveness of outer hair cell (OHC) electro-motility in vivo has been challenged by the expected low-pass filtering of the transmembrane potential due to the cell's own capacitance. The OHC electromotility is characterized here by an electromechanical ratio defined as the ratio of the OHC contraction to the transmembrane potential. This ratio has been measured in isolated cells to be approximately 26 nm/mV. We estimate the OHC electromechanical ratio in vivo from the recently measured displacements of the reticular lamina and the basilar membrane near the 19 kHz characteristic frequency in the basal region of guinea pig cochlea. Our analysis strongly suggests OHC electromotility process is effective for cochlear amplification in vivo at least around the characteristic frequency of the basal location in spite of the low-pass filtering.

Ramamoorthy, Sripriya; Nuttall, Alfred L.

2011-11-01

379

In vivo absorption spectroscopy for absolute measurement  

PubMed Central

In in vivo spectroscopy, there are differences between individual subjects in parameters such as tissue scattering and sample concentration. We propose a method that can provide the absolute value of a particular substance concentration, independent of these individual differences. Thus, it is not necessary to use the typical statistical calibration curve, which assumes an average level of scattering and an averaged concentration over individual subjects. This method is expected to greatly reduce the difficulties encountered during in vivo measurements. As an example, for in vivo absorption spectroscopy, the method was applied to the reflectance measurement in retinal vessels to monitor their oxygen saturation levels. This method was then validated by applying it to the tissue phantom under a variety of absorbance values and scattering efficiencies. PMID:23082298

Furukawa, Hiromitsu; Fukuda, Takashi

2012-01-01

380

In vivo magnetic resonance spectroscopy of liver tumors and metastases  

PubMed Central

Primary liver cancer is the fifth most common malignancy in men and the eighth in women worldwide. The liver is also the second most common site for metastatic spread of cancer. To assist in the diagnosis of these liver lesions non-invasive advanced imaging techniques are desirable. Magnetic resonance (MR) is commonly used to identify anatomical lesions, but it is a very versatile technique and also can provide specific information on tumor pathophysiology and metabolism, in particular with the application of MR spectroscopy (MRS). This may include data on the type, grade and stage of tumors, and thus assist in further management of the disease. The purpose of this review is to summarize and discuss the available literature on proton, phosphorus and carbon-13-MRS as performed on primary liver tumors and metastases, with human applications as the main perspective. Upcoming MRS approaches with potential applications to liver tumors are also included. Since knowledge of some technical background is indispensable to understand the results, a basic introduction of MRS and some technical issues of MRS as applied to tumors and metastases in the liver are described as well. In vivo MR spectroscopy of tumors in a metabolically active organ such as the liver has been demonstrated to provide important information on tumor metabolism, but it also is challenging as compared to applications on some other tissues, in particular in humans, mostly because of its abdominal location where movement may be a disturbing factor. PMID:22215937

ter Voert, EGW; Heijmen, L; van Laarhoven, HWM; Heerschap, A

2011-01-01

381

In vivo high-resolution structural imaging of large arteries in small rodents using two-photon laser scanning microscopy  

NASA Astrophysics Data System (ADS)

In vivo (molecular) imaging of the vessel wall of large arteries at subcellular resolution is crucial for unraveling vascular pathophysiology. We previously showed the applicability of two-photon laser scanning microscopy (TPLSM) in mounted arteries ex vivo. However, in vivo TPLSM has thus far suffered from in-frame and between-frame motion artifacts due to arterial movement with cardiac and respiratory activity. Now, motion artifacts are suppressed by accelerated image acquisition triggered on cardiac and respiratory activity. In vivo TPLSM is performed on rat renal and mouse carotid arteries, both surgically exposed and labeled fluorescently (cell nuclei, elastin, and collagen). The use of short acquisition times consistently limit in-frame motion artifacts. Additionally, triggered imaging reduces between-frame artifacts. Indeed, structures in the vessel wall (cell nuclei, elastic laminae) can be imaged at subcellular resolution. In mechanically damaged carotid arteries, even the subendothelial collagen sheet (~1 ?m) is visualized using collagen-targeted quantum dots. We demonstrate stable in vivo imaging of large arteries at subcellular resolution using TPLSM triggered on cardiac and respiratory cycles. This creates great opportunities for studying (diseased) arteries in vivo or immediate validation of in vivo molecular imaging techniques such as magnetic resonance imaging (MRI), ultrasound, and positron emission tomography (PET).

Megens, Remco T. A.; Reitsma, Sietze; Prinzen, Lenneke; Oude Egbrink, Mirjam G. A.; Engels, Wim; Leenders, Peter J. A.; Brunenberg, Ellen J. L.; Reesink, Koen D.; Janssen, Ben J. A.; Ter Haar Romeny, Bart M.; Slaaf, Dick W.; van Zandvoort, Marc A. M. J.

2010-01-01

382

In vivo detection of magnetic labeled oxidized multi-walled carbon nanotubes by magnetic resonance imaging  

NASA Astrophysics Data System (ADS)

Functionalized carbon nanotubes (f-CNTs) have been widely used in bio-medicine as drug carriers, bio-sensors, imaging agents and tissue engineering additives, which demands better understanding of their in vivo behavior because of the increasing exposure potential to humans. However, there are limited studies to investigate the in vivo biodistribution and elimination of f-CNTs. In this study, superparamagnetic iron oxides (SPIOs) were used to label oxidized multiwalled carbon nanotubes (o-MWCNTs) for in vivo distribution study of o-MWCNTs by magnetic resonance imaging (MRI). SPIO labeled o-MWCNTs ((SPIO)o-MWCNTs) were prepared by a hydrothermal reaction process, and characterized by TEM, XRD and magnetometer. (SPIO)o-MWCNTs exhibited superparamagnetic property, excellent biocompatibility and stability. The intravenously injected (SPIO)o-MWCNTs were observed in liver, kidney and spleen, while the subcutaneously injected (SPIO)o-MWCNTs could be only detected in sub mucosa. Most of the intravenously injected (SPIO)o-MWCNTs could be eliminated from liver, spleen, kidney and sub mucosa on 4 d post injection (P.I.). However, the residual o-MWCNTs could induce 30–40% MRI signal-to-noise ratio changes in these tissues even on 30 d P.I. This in vivo biodistribution and elimination information of o-MWCNTs will greatly facilitate the application of f-CNT based nanoproducts in biomedicine. In addition, the magnetic labeling method provides an approach to investigate the in vivo biodistribution and clearance of other nanomaterials.

Li, Ruibin; Wu, Ren’an; Zhao, Liang; Qin, Hongqiang; Wu, Jianlin; Zhang, Jingwen; Bao, Ruyi; Zou, Hanfa

2014-12-01

383

In vivo molecular and morphological imaging by real time confocal mini-microscopy  

NASA Astrophysics Data System (ADS)

We evaluated a newly developed miniaturized confocal laser microscopy probe for real-time in vivo molecular and morphological imaging of normal, inflammatory, and malignant tissue in rodents. In the rigid mini-microscopy probe (diameter 7 mm), a single line laser delivers an excitation wavelength of 488 nm. Optical slice thickness is 7 ?m, lateral resolution 0.7 ?m. The range of the z-axis is 0 - 250 ?m below the tissue surface. Organ systems were examined in vivo in rodent models of human diseases. FITC-labeled Lycopersion esculentum lectin was injected or selected cell populations stained for molecular targeting. Morphological imaging was performed using fluorescein sodium, FITC-labeled dextran, and/or acriflavine hydrochloride. Cellular and subcellular details could be readily visualised in vivo at high resolution. Tissue characteristics of different organs were rendered at real time. Selective blood cell staining allowed observation of blood flow and cell migration. Inflammatory diseases such as hepatitis were diagnosed, and tumors were characterized under microscopic control in vivo. Confocal mini-microscopy allows real time in vivo molecular and morphological histologic imaging at high resolution of normal and diseased tissue. Since confocal microscopy is applicable to humans, this technology will have a high impact on different faculties in medicine.

Goetz, Martin; Gregor, Sebastian; Fottner, Christian; Garcia-Lazaro, Jose; Schirrmacher, Esther; Kempski, Oliver; Bartenstein, Peter; Weber, Mathias; Biesterfeld, Stefan; Galle, Peter R.; Neurath, Markus F.; Kiesslich, Ralf

2006-02-01

384

Fiber-optic multiphoton flow cytometry in whole blood and in vivo  

NASA Astrophysics Data System (ADS)

Circulating tumor cells in the bloodstream are sensitive indicators for metastasis and disease prognosis. Circulating cells have usually been monitored via extraction from blood, and more recently in vivo using free-space optics; however, long-term intravital monitoring of rare circulating cells remains a major challenge. We demonstrate the application of a two-photon-fluorescence optical fiber probe for the detection of cells in whole blood and in vivo. A double-clad fiber was used to enhance the detection sensitivity. Two-channel detection was employed to enable simultaneous measurement of multiple fluorescent markers. Because the fiber probe circumvents scattering and absorption from whole blood, the detected signal strength from fluorescent cells was found to be similar in phosphate-buffered saline (PBS) and in whole blood. The detection efficiency of cells labeled with the membrane-binding dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindoldicarbocyanine, 4-chlorobenzenesulfonate (DiD) was demonstrated to be the same in PBS and in whole blood. A high detection efficiency of green fluorescent protein (GFP)-expressing cells in whole blood was also demonstrated. To characterize in vivo detection, DiD-labeled untransfected and GFP-transfected cells were injected into live mice, and the cell circulation dynamics was monitored in real time. The detection efficiency of GFP-expressing cells in vivo was consistent with that observed ex vivo in whole blood.

Chang, Yu-Chung; Ye, Jing Yong; Thomas, Thommey P.; Cao, Zhengyi; Kotlyar, Alina; Tkaczyk, Eric R.; Baker, James R.; Norris, Theodore B.

2010-07-01

385

In Vivo Imaging of ParaCEST Agents Using Frequency Labeled Exchange Transfer (FLEX) MRI  

PubMed Central

Purpose A main obstacle to in vivo applications of paramagnetic chemical exchange saturation transfer (paraCEST) is interference from endogenous tissue magnetization transfer contrast (MTC). The suitability of excitation-based frequency labeled exchange transfer (FLEX) to separate out such MTC effects in vivo was tested. Methods The FLEX sequence measures modulation of the water signal based on the chemical shift evolution of solute proton magnetization as a function of evolution time. Time-domain analysis of this water signal allows identification of different solute components and provides a mechanism to separate out the rapidly decaying MTC components with short T2* values. Results FLEX imaging of paraCEST agents was possible in vitro in phantoms and in vivo in mouse kidneys and bladder. The results demonstrated that FLEX is capable of separating out the MTC signal from tissues in vivo while providing a quantitative exchange rate for the rapidly exchanging paraCEST water protons by fitting the FLEX time-domain signal to FLEX theory. Conclusions The first in vivo FLEX images of a paraCEST agent were acquired, which allowed separation out the tissue MTC components. These results show that FLEX imaging has potential for imaging the distribution of functional paraCEST agents in biological tissues. PMID:23468384

Lin, Chien-Yuan; Yadav, Nirbhay N.; Ratnakar, James; Sherry, A. Dean; van Zijl, Peter C. M.

2013-01-01

386

In vivo virtual intraoperative surgical photoacoustic microscopy  

SciTech Connect

We developed a virtual intraoperative surgical photoacoustic microscopy system by combining with a commercial surgical microscope and photoacoustic microscope (PAM). By sharing the common optical path in the microscope and PAM system, we could acquire the PAM and microscope images simultaneously. Moreover, by employing a beam projector to back-project 2D PAM images onto the microscope view plane as augmented reality, the conventional microscopic and 2D cross-sectional PAM images are concurrently mapped on the plane via an ocular lens of the microscope in real-time. Further, we guided needle insertion into phantom ex vivo and mice skins in vivo.

Han, Seunghoon, E-mail: hsh860504@gmail.com; Kim, Sehui, E-mail: sehui0916@nate.com; Kim, Jeehyun, E-mail: jeehk@knu.ac.kr, E-mail: chulhong@postech.edu [School of Electrical Engineering and Computer Science, Kyungpook National University, Daegu 702-701 (Korea, Republic of)] [School of Electrical Engineering and Computer Science, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Lee, Changho, E-mail: ch31037@postech.edu; Jeon, Mansik, E-mail: msjeon@postech.edu [Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of)] [Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Kim, Chulhong, E-mail: jeehk@knu.ac.kr, E-mail: chulhong@postech.edu [Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of) [Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Department of Biomedical Engineering, The State University of New York at Buffalo, Buffalo, New York 14221 (United States)

2013-11-11

387

In vivo virtual intraoperative surgical photoacoustic microscopy  

PubMed Central

We developed a virtual intraoperative surgical photoacoustic microscopy system by combining with a commercial surgical microscope and photoacoustic microscope (PAM). By sharing the common optical path in the microscope and PAM system, we could acquire the PAM and microscope images simultaneously. Moreover, by employing a beam projector to back-project 2D PAM images onto the microscope view plane as augmented reality, the conventional microscopic and 2D cross-sectional PAM images are concurrently mapped on the plane via an ocular lens of the microscope in real-time. Further, we guided needle insertion into phantom ex vivo and mice skins in vivo. PMID:24343135

Han, Seunghoon; Lee, Changho; Kim, Sehui; Jeon, Mansik; Kim, Jeehyun; Kim, Chulhong

2013-01-01

388

Vitamin E Reverses Multidrug Resistance In Vitro and In Vivo  

PubMed Central

Multidrug resistance (MDR) is a major obstacle to successful and effective chemotherapeutic treatments of cancers. This study explored the reversal effects of vitamin E on MDR tumor cells in vitro and in vivo, elucidating the potential mechanism of this reversal. VE at a concentration of 50 ?M exhibited a significant reversal of the MDR effect (compared to only PTX in DMSO, p < 0.05) in two human MDR cell lines (H460/taxR and KB-8-5). The MDR cell xenograft model was established to investigate the effect of VE on reversing MDR in vivo. Mice intravenously injected with Taxol (10 mg/kg) with VE (500 mg/kg, IP) showed an ability to overcome the MDR. VE and its derivatives can significantly increase intracellular accumulation of rhodamine 123 and doxorubicin (P-gp substrate), but not alter the levels of P-gp expression. These treatments also did not decrease the levels of intracellular ATP, but were still able to inhibit the verapamil-induced ATPase activity of P-gp. The new application of VE as an MDR sensitizer will be attractive due to the safety of this treatment. PMID:23624302

Tang, Jingling; Fu, Qiang; Wang, Yongjun; Racette, Kelly; Wang, Dun; Liu, Feng

2013-01-01

389

Metabolic Flux and Compartmentation Analysis in the Brain In vivo  

PubMed Central

Through significant developments and progresses in the last two decades, in vivo localized nuclear magnetic resonance spectroscopy (MRS) became a method of choice to probe brain metabolic pathways in a non-invasive way. Beside the measurement of the total concentration of more than 20 metabolites, 1H MRS can be used to quantify the dynamics of substrate transport across the blood-brain barrier by varying the plasma substrate level. On the other hand, 13C MRS with the infusion of 13C-enriched substrates enables the characterization of brain oxidative metabolism and neurotransmission by incorporation of 13C in the different carbon positions of amino acid neurotransmitters. The quantitative determination of the biochemical reactions involved in these processes requires the use of appropriate metabolic models, whose level of details is strongly related to the amount of data accessible with in vivo MRS. In the present work, we present the different steps involved in the elaboration of a mathematical model of a given brain metabolic process and its application to the experimental data in order to extract quantitative brain metabolic rates. We review the recent advances in the localized measurement of brain glucose transport and compartmentalized brain energy metabolism, and how these reveal mechanistic details on glial support to glutamatergic and GABAergic neurons. PMID:24194729

Lanz, Bernard; Gruetter, Rolf; Duarte, João M. N.

2013-01-01

390

In vivo transcostal histotripsy therapy without aberration correction  

NASA Astrophysics Data System (ADS)

This study investigates the in vivo therapeutic capabilities of transcostal histotripsy without using aberration correction mechanisms and its thermal impact on overlying tissues. Non-invasive liver treatments were conducted in eight pigs, with four lesions generated through transcostal windows with full ribcage obstruction and four lesions created through transabdominal windows without rib coverage. Treatments were performed by a 750 kHz focused transducer using 5 cycle pulses at 200 Hz PRF, with estimated in situ peak negative pressures of 13-17 MPa. Temperatures on overlying tissues including the ribs were measured with needle thermocouples inserted superficially beneath the skin. Treatments of approximately 40 min were applied, allowing overlying tissue temperatures to reach saturation. Lesions yielded statistically comparable ablation volumes of 3.6 ± 1.7 cm3 and 4.5 ± 2.0 cm3 in transcostal and transabdominal treatments, respectively. The average temperature increase observed in transcostal treatments was 3.9 ± 2.1 °C, while transabdominal treatments showed an increase of 1.7 ± 1.3 °C. No damage was seen on the ribcage or other overlying tissues. These results indicate that histotripsy can achieve effective treatment through the ribcage in vivo without requiring correction mechanisms, while inducing no substantial thermal effects or damage to overlying tissues. Such capabilities could benefit several non-invasive therapy applications involving transcostal treatment windows.

Kim, Y.; Vlaisavljevich, E.; Owens, G. E.; Allen, S. P.; Cain, C. A.; Xu, Z.

2014-06-01

391

Biodegradable optode-based nanosensors for in vivo monitoring  

PubMed Central

Optode-based fluorescent nanosensors are being developed for monitoring important diseased states such as hyponatremia and diabetes. However, traditional optode-based sensors are composed of nonbiodegradable polymers such as polyvinyl chloride (PVC) raising toxicity concerns for long-term in vivo use. Here, we report the development of the first biodegradable optode-based nanosensors that maintain sensing characteristics identical to traditional optode sensors. The polymer matrix of these sensors is composed of polycaprolactone (PCL) and a citric acid ester plasticizer. The PCL-based nanosensors yielded a dynamic and reversible response to sodium, were tuned to respond to extracellular sodium concentrations, and had a lifetime of at least 14 days at physiological temperature. When in the presence of lipase, the nanosensors degraded within 4 hours at lipase concentrations found in the liver but were present after 3 days at lipase concentrations found in serum. This development of biodegradable nanosensors is not only necessary for future in vivo applications, but it has also created a new sensor platform that can be extended to other sensing mechanisms such as for small molecules or enzymes. PMID:22725692

Balaconis, Mary K.; Clark, Heather A.

2012-01-01

392

In vivo cell tracking and quantification method in adult zebrafish  

NASA Astrophysics Data System (ADS)

Zebrafish have become a powerful vertebrate model organism for drug discovery, cancer and stem cell research. A recently developed transparent adult zebrafish using double pigmentation mutant, called casper, provide unparalleled imaging power in in vivo longitudinal analysis of biological processes at an anatomic resolution not readily achievable in murine or other systems. In this paper we introduce an optical method for simultaneous visualization and cell quantification, which combines the laser scanning confocal microscopy (LSCM) and the in vivo flow cytometry (IVFC). The system is designed specifically for non-invasive tracking of both stationary and circulating cells in adult zebrafish casper, under physiological conditions in the same fish over time. The confocal imaging part in this system serves the dual purposes of imaging fish tissue microstructure and a 3D navigation tool to locate a suitable vessel for circulating cell counting. The multi-color, multi-channel instrument allows the detection of multiple cell populations or different tissues or organs simultaneously. We demonstrate initial testing of this novel instrument by imaging vasculature and tracking circulating cells in CD41: GFP/Gata1: DsRed transgenic casper fish whose thrombocytes/erythrocytes express the green and red fluorescent proteins. Circulating fluorescent cell incidents were recorded and counted repeatedly over time and in different types of vessels. Great application opportunities in cancer and stem cell researches are discussed.

Zhang, Li; Alt, Clemens; Li, Pulin; White, Richard M.; Zon, Leonard I.; Wei, Xunbin; Lin, Charles P.

2012-03-01

393

Neurovascular coupling: in vivo optical techniques for functional brain imaging  

PubMed Central

Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology. PMID:23631798

2013-01-01

394

SQUID-Detected In Vivo MRI at Microtesla Magnetic Fields  

SciTech Connect

We use a low transition temperature (T{sub c}) Super-conducting Quantum Interference Device (SQUID) to perform in vivo magnetic resonance imaging (MRI) at magnetic fields around 100 microtesla, corresponding to proton Larmor frequencies of about 5 kHz. In such low fields, broadening of the nuclear magnetic resonance lines due to inhomogeneous magnetic fields and susceptibility variations of the sample are minimized, enabling us to obtain high quality images. To reduce environmental noise the signal is detected by a second-order gradiometer, coupled to the SQUID, and the experiment is surrounded by a 3-mm thick Al shield. To increase the signal-to-noise ratio (SNR), we prepolarize the samples in a field up to 100 mT. Three-dimensional images are acquired in less than 6 minutes with a standard spin-echo phase-encoding sequence. Using encoding gradients of {approx}100 {micro}T/m we obtain three-dimensional images of bell peppers with a resolution of 2 x 2 x 8 mm{sup 3}. Our system is ideally suited to acquiring images of small, peripheral parts of the human body such as hands and arms. In vivo images of an arm, acquired at 132 {micro}T, show 24-mm sections of the forearm with a resolution of 3 x 3 mm{sup 2} and a SNR of 10. We discuss possible applications of MRI at these low magnetic fields.

Moble, Michael; Myers, Whittier R; Lee, SeungKyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

2005-06-01

395

In vivo immobilization of D-hydantoinase in Escherichia coli.  

PubMed

D-P-Hydroxyphenylglycine (D-HPG) is a precursor required for the synthesis of semi-synthetic antibiotics. This unnatural amino acid can be produced by a transformation reaction mediated by D-hydantoinase (D-HDT) and d-amidohydrolase. In this study, a method was developed to integrate production and immobilization of recombinant D-HDT in vivo. This was approached by first fusion of the gene encoding D-HDT with phaP (encoding phasin) of Ralstonia eutropha H16. The fusion gene was then expressed in the Escherichia coli strain that carried a heterologous synthetic pathway for polyhydroxyalkanoate (PHA). As a result, d-HDT was found to associate with isolated PHA granules. Further characterization illustrated that D-HDT immobilized on PHA exhibited the maximum activity at pH 9 and 60°C and had a half-life of 95 h at 40°C. Moreover, PHA-bound d-HDT could be reused for 8 times with the conversion yield exceeding 90%. Overall, it illustrates the feasibility of this approach to facilitate in vivo immobilization of enzymes in heterologous E. coli strain, which may open a new avenue of enzyme application in industry. PMID:24508023

Chen, Shan-Yu; Chien, Yi-Wen; Chao, Yun-Peng

2014-07-01

396

Thermostabilization of firefly luciferase by in vivo directed evolution.  

PubMed

Firefly luciferase is widely used in a number of areas of biotechnology and molecular biology. However, rapid inactivation of wild-type (WT) luciferases at elevated temperatures often hampers their application. A simple non-lethal in vivo screening scheme was used to identify thermostable mutants of luciferase in Escherichia coli colonies. This scheme allowed carrying out each cycle of mutagenesis in a rapid and efficient manner. Four rounds of directed evolution were conducted on a part of the gene coding for amino acid residues 130-390 of Luciola mingrelica luciferase. The resultant mutant designated 4TS had a half-life of 10 h at 42°C, which is 65-fold higher compared with the WT luciferase. Moreover, the mutant 4TS showed a 1.9-fold increase in specific activity, 5.7-fold reduction of K(m) for ATP and a higher-temperature optimum compared with the WT enzyme. 4TS contains eight mutations, four of which are suggested to be mainly responsible for the enhancement of thermostability: R211L, A217V, E356K and S364C. Thus, directed evolution with non-lethal colony screening for in vivo bioluminescence activity proved to be an effective and efficient approach for increasing thermal stability of luciferase while retaining high catalytic activity. PMID:21900306

Koksharov, Mikhail I; Ugarova, Natalia N

2011-11-01

397

In vivo bone aluminum measurements in patients with renal disease  

SciTech Connect

Contamination of the dialysis solution with trace amounts of aluminum and long-term use of aluminum-based phosphate binders have led to increased body burden of aluminum in patients with end-stage renal disease. A significant clinical problem associated with aluminum-overload is the early diagnosis of aluminum-induced dialysis dementia and osteomalacic osteodystrophy. There are few, if any, blood or urine indices that provide an early monitor of this bone disease, especially in the asymptomatic patient. Although a bone biopsy is usually the basis for the final clinical diagnosis, this procedure is not recommended for routine monitoring of patients. The present technique demonstrates the direct in vivo measurement of bone aluminum levels in patients with renal failure. The interference normally present from activation of bone phosphorus is eliminated by using a thermal/epithermal neutron beam. For the clinical management of the patients, the Al/Ca ratio for the hand may be more useful than an absolute measurement of the total body or skeletal aluminum burden. The relationship between the increased serum Al levels following disferrioxamine infusion and the direct in vivo measurement of bone aluminum using the Al/Ca ratio are currently un