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Sample records for vivo oxygen-sensing applications

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

    PubMed Central

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

    2014-01-01

    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

  2. Optical oxygen sensing systems for drug discovery applications: Respirometric Screening Technology (RST)

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitri B.; Hynes, James; Fernandes, Richard

    2005-11-01

    Quenched-fluorescence oxygen sensing allows non-chemical, reversible, real-time monitoring of molecular oxygen and rates of oxygen consumption in biological samples. Using this approach we have developed Respirometric Screening Technology (RST); a platform which facilitates the convenient analysis of cellular oxygen uptake. This in turn allows the investigation of compounds and processes which affect respiratory activity. The RST platform employs soluble phosphorescent oxygen-sensitive probes, which may be assessed in standard microtitter plates on a fluorescence plate reader. New formats of RST assays and time-resolved fluorescence detection instrumentation developed by Luxcel provide improvements in assay sensitivity, miniaturization and overall performance. RST has a diverse range of applications in drug discovery area including high throughput analysis of mitochondrial function; studies of mechanisms of toxicity and apoptosis; cell and animal based screening of compound libraries and environmental samples; and, sterility testing. RST has been successfully validated with a range of practical targets and adopted by several leading pharmaceutical companies.

  3. Early non-destructive biofouling detection and spatial distribution: Application of oxygen sensing optodes.

    PubMed

    Farhat, N M; Staal, M; Siddiqui, A; Borisov, S M; Bucs, Sz S; Vrouwenvelder, J S

    2015-10-15

    Biofouling is a serious problem in reverse osmosis/nanofiltration (RO/NF) applications, reducing membrane performance. Early detection of biofouling plays an essential role in an adequate anti-biofouling strategy. Presently, fouling of membrane filtration systems is mainly determined by measuring changes in pressure drop, which is not exclusively linked to biofouling. Non-destructive imaging of oxygen concentrations (i) is specific for biological activity of biofilms and (ii) may enable earlier detection of biofilm accumulation than pressure drop. The objective of this study was to test whether transparent luminescent planar O2 optodes, in combination with a simple imaging system, can be used for early non-destructive biofouling detection. This biofouling detection is done by mapping the two-dimensional distribution of O2 concentrations and O2 decrease rates inside a membrane fouling simulator (MFS). Results show that at an early stage, biofouling development was detected by the oxygen sensing optodes while no significant increase in pressure drop was yet observed. Additionally, optodes could detect spatial heterogeneities in biofouling distribution at a micro scale. Biofilm development started mainly at the feed spacer crossings. The spatial and quantitative information on biological activity will lead to better understanding of the biofouling processes, contributing to the development of more effective biofouling control strategies. PMID:26117369

  4. Oxygen sensing and signaling.

    PubMed

    van Dongen, Joost T; Licausi, Francesco

    2015-01-01

    Oxygen is an indispensable substrate for many biochemical reactions in plants, including energy metabolism (respiration). Despite its importance, plants lack an active transport mechanism to distribute oxygen to all cells. Therefore, steep oxygen gradients occur within most plant tissues, which can be exacerbated by environmental perturbations that further reduce oxygen availability. Plants possess various responses to cope with spatial and temporal variations in oxygen availability, many of which involve metabolic adaptations to deal with energy crises induced by low oxygen. Responses are induced gradually when oxygen concentrations decrease and are rapidly reversed upon reoxygenation. A direct effect of the oxygen level can be observed in the stability, and thus activity, of various transcription factors that control the expression of hypoxia-induced genes. Additional signaling pathways are activated by the impact of oxygen deficiency on mitochondrial and chloroplast functioning. Here, we describe the molecular components of the oxygen-sensing pathway. PMID:25580837

  5. 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

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

    2010-01-01

    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

  6. A miniature inexpensive, oxygen sensing element

    SciTech Connect

    Arenz, R.W.

    1991-10-07

    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.

  7. Oxygen sensing and signal transduction in hypoxic pulmonary vasoconstriction.

    PubMed

    Sommer, Natascha; Strielkov, Ievgen; Pak, Oleg; Weissmann, Norbert

    2016-01-01

    Hypoxic pulmonary vasoconstriction (HPV), also known as the von Euler-Liljestrand mechanism, is an essential response of the pulmonary vasculature to acute and sustained alveolar hypoxia. During local alveolar hypoxia, HPV matches perfusion to ventilation to maintain optimal arterial oxygenation. In contrast, during global alveolar hypoxia, HPV leads to pulmonary hypertension. The oxygen sensing and signal transduction machinery is located in the pulmonary arterial smooth muscle cells (PASMCs) of the pre-capillary vessels, albeit the physiological response may be modulated in vivo by the endothelium. While factors such as nitric oxide modulate HPV, reactive oxygen species (ROS) have been suggested to act as essential mediators in HPV. ROS may originate from mitochondria and/or NADPH oxidases but the exact oxygen sensing mechanisms, as well as the question of whether increased or decreased ROS cause HPV, are under debate. ROS may induce intracellular calcium increase and subsequent contraction of PASMCs via direct or indirect interactions with protein kinases, phospholipases, sarcoplasmic calcium channels, transient receptor potential channels, voltage-dependent potassium channels and L-type calcium channels, whose relevance may vary under different experimental conditions. Successful identification of factors regulating HPV may allow development of novel therapeutic approaches for conditions of disturbed HPV. PMID:26493804

  8. A rhenium complex doped in a silica molecular sieve for molecular oxygen sensing: Construction and characterization.

    PubMed

    Yang, Xiaozhou; Li, Yanxiao

    2016-01-15

    This paper reported a diamine ligand and its Re(I) complex for potential application in oxygen sensing. The novelty of this diamine ligand localized at its increased conjugation chain which had a typical electron-withdrawing group of 1,3,4-oxadiazole. Electronic distribution of excited electrons and their lifetime were supposed to be increased, favoring oxygen sensing collision. This hypothesis was confirmed by single crystal analysis, theoretical calculation and photophysical measurement. It was found that this Re(I) complex had a long-lived emission peaking at 545 nm, favoring sensing application. By doping this complex into a silica matrix MCM-41, oxygen sensing performance and mechanism of the resulting composites were discussed in detail. Non-linear Stern-Volmer working curves were observed with maximum sensitivity of 5.54 and short response time of ~6 s. PMID:26478986

  9. A rhenium complex doped in a silica molecular sieve for molecular oxygen sensing: Construction and characterization

    NASA Astrophysics Data System (ADS)

    Yang, Xiaozhou; Li, Yanxiao

    2016-01-01

    This paper reported a diamine ligand and its Re(I) complex for potential application in oxygen sensing. The novelty of this diamine ligand localized at its increased conjugation chain which had a typical electron-withdrawing group of 1,3,4-oxadiazole. Electronic distribution of excited electrons and their lifetime were supposed to be increased, favoring oxygen sensing collision. This hypothesis was confirmed by single crystal analysis, theoretical calculation and photophysical measurement. It was found that this Re(I) complex had a long-lived emission peaking at 545 nm, favoring sensing application. By doping this complex into a silica matrix MCM-41, oxygen sensing performance and mechanism of the resulting composites were discussed in detail. Non-linear Stern-Volmer working curves were observed with maximum sensitivity of 5.54 and short response time of ~ 6 s.

  10. Biosupercapacitors for powering oxygen sensing devices.

    PubMed

    Kizling, Michal; Draminska, Sylwia; Stolarczyk, Krzysztof; Tammela, Petter; Wang, Zhaohui; Nyholm, Leif; Bilewicz, Renata

    2015-12-01

    A biofuel cell comprising electrodes based on supercapacitive materials - carbon nanotubes and nanocellulose/polypyrrole composite was utilized to power an oxygen biosensor. Laccase Trametes versicolor, immobilized on naphthylated multi walled carbon nanotubes, and fructose dehydrogenase, adsorbed on a porous polypyrrole matrix, were used as the cathode and anode bioelectrocatalysts, respectively. The nanomaterials employed as the supports for the enzymes increased the surface area of the electrodes and provide direct contact with the active sites of the enzymes. The anode modified with the conducting polymer layer exhibited significant pseudocapacitive properties providing superior performance also in the high energy mode, e.g., when switching on/off the powered device. Three air-fructose biofuel cells connected in a series converted chemical energy into electrical giving 2 mW power and open circuit potential of 2V. The biofuel cell system was tested under various externally applied resistances and used as a powering unit for a laboratory designed two-electrode minipotentiostat and a laccase based sensor for oxygen sensing. Best results in terms of long time measurement of oxygen levels were obtained in the pulse mode -45 s for measurement and 15 min for self-recharging of the powering unit. PMID:25960258

  11. Evolution and physiology of neural oxygen sensing

    PubMed Central

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

    2014-01-01

    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

  12. Quality assessment of packaged foods by optical oxygen sensing

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitri B.; O'Mahony, Fiach C.; Kerry, Joe P.; Ogurtsov, Vladimir I.

    2005-11-01

    A phase-fluorometric oxygen sensor system has been developed, which allows non-destructive measurement of residual oxygen levels in sealed containers such as packaged foods. It operates with disposable solid-state sensors incorporated in each pack, and a portable detector which interrogates with the sensors through a (semi)transparent packaging material. The system has been optimized for packaging applications and validated in small and medium scale trials with different types of food, including MAP hams, cheese, convenience foods, smoked fish, bakery. It has demonstrated high efficiency in monitoring package integrity, oxygen profiles in packs, performance of packaging process and many other research and quality control tasks, allowing control of 100% of packs. The low-cost batch-calibrated sensors have demonstrated reliability, safety, stability including direct contact with food, high efficiency in the low oxygen range. Another system, which also employs the fluorescence-based oxygen sensing approach, provides rapid assessment of microbial contamination (total viable counts) in complex samples such as food homogenates, industrial waste, environmental samples, etc. It uses soluble oxygen-sensitive probes, standard microtitter plates and fluorescence measurements on conventional plate reader to monitor growth of aerobic bacteria in small test samples (e.g. food homogenates) via their oxygen respiration. The assay provides high sample through put, miniaturization, speed, and can serve as alternative to the established methods such as agar plate colony counts and turbidimetry.

  13. Morphology impact on oxygen sensing ability of Ru(dpp)3Cl2 containing biocompatible polymers.

    PubMed

    Zhao, Susan Y; Harrison, Benjamin S

    2015-08-01

    Especially for tissue engineering applications, the diffusion of oxygen is a critical factor affecting spatial distribution and migration of cells. The cellular oxygen demand also fluctuates depending on tissue type and growth phase. Sensors that determine dissolved oxygen levels under biological conditions provide critical metabolic information about the growing cells as well as the state of the tissue culture within the tissue scaffold. This work focused on the effect of the scaffold morphology on the oxygen sensing response time. It was found that electrospun scaffolds had a faster oxygen-sensing response time than their bulk film counterparts. Tris-(4,7-diphenyl-1,10-phenanthroline) ruthenium (II) dichloride doped electrospun fiber mats of polycaprolactone (PCL) were found to be the most responsive to the presence of oxygen, followed by polyethylene (PEO) glycol mats. Systems containing poly vinyl alcohol were found to be the least responsive. This would suggest that, out of all the polymers tested, PCL and PEO are the most suitable biomaterials for oxygen-sensing applications. PMID:26042716

  14. Ratiometric oxygen sensing using lanthanide luminescent emitting interfaces.

    PubMed

    Lehr, Joshua; Tropiano, Manuel; Beer, Paul D; Faulkner, Stephen; Davis, Jason J

    2015-11-14

    Herein we describe the first example of a ratiometric lanthanide luminescent oxygen sensing interface. Immobilisation of terbium and europium cyclen complexes on glass substrates was achieved by a novel aryl nitrene photografting approach. The resulting interfaces demonstrated a ratiometric oxygen response between 0 and 0.2 atm partial oxygen pressure. PMID:26376829

  15. Superhydrophobic porous surfaces: dissolved oxygen sensing.

    PubMed

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

    2015-02-18

    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

  16. Ceramide Mediates Acute Oxygen Sensing in Vascular Tissues

    PubMed Central

    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

    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, 114. PMID:23725018

  17. TwoPhoton Oxygen Sensing with Quantum DotPorphyrin Conjugates

    PubMed Central

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

    2013-01-01

    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 0160 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 selfassembled nanosensors. Appreciable overlap between QD emission and porphyrin absorption features results in efficient Frster resonance energy transfer (FRET) for signal transduction in these sensors. The QD serves as a photon antenna, enhancing porphyrin emission under both one and twophoton excitation, demonstrating that QDpalladium porphyrin conjugates may be used for oxygen sensing over physiological oxygen ranges. PMID:23978247

  18. The Regulation of Pulmonary Inflammation by the Hypoxia-Inducible Factor–Hydroxylase Oxygen-Sensing Pathway

    PubMed Central

    Walmsley, Sarah R.

    2014-01-01

    Although the hypoxia-inducible factor (HIF)–hydroxylase oxygen-sensing pathway has been extensively reviewed in the context of cellular responses to hypoxia and cancer biology, its importance in regulating innate immune biology is less well described. In this review, we focus on the role of the HIF-hydroxylase pathway in regulating myeloid cell responses and its relevance to inflammatory lung disease. The more specific roles of individual HIF/ prolyl hydroxylase pathway members in vivo are discussed in the context of lineage-specific rodent models of inflammation, with final reference made to the therapeutic challenges of targeting the HIF/hydroxylase pathway in immune cells. PMID:25525731

  19. Interaction of Hydrogen Sulfide with Oxygen Sensing under Hypoxia

    PubMed Central

    Wu, Bo; Teng, Huajian; Zhang, Li; Li, Hong; Li, Jing; Wang, Lina; Li, Hongzhu

    2015-01-01

    Based on the discovery of endogenous H2S production, many in depth studies show this gasotransmitter with a variety of physiological and pathological functions. Three enzymes, cystathionine ?-synthase (CBS), cystathionine ?-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (MST), are involved in enzymatic production of H2S. Emerging evidence has elucidated an important protective role of H2S in hypoxic conditions in many mammalian systems. However, the mechanisms by which H2S senses and responses to hypoxia are largely elusive. Hypoxia-inducible factors (HIFs) function as key regulators of oxygen sensing, activating target genes expression under hypoxia. Recent studies have shown that exogenous H2S regulates HIF action in different patterns. The activation of carotid bodies is a sensitive and prompt response to hypoxia, rapidly enhancing general O2 supply. H2S has been identified as an excitatory mediator of hypoxic sensing in the carotid bodies. This paper presents a brief review of the roles of these two pathways which contribute to hypoxic sensing of H2S. PMID:26078818

  20. Oxygen sensing coordinates photomorphogenesis to facilitate seedling survival.

    PubMed

    Abbas, Mohamad; Berckhan, Sophie; Rooney, Daniel J; Gibbs, Daniel J; Vicente Conde, Jorge; Sousa Correia, Cristina; Bassel, George W; Marn-de la Rosa, Nora; Len, Jos; Alabad, David; Blzquez, Miguel A; Holdsworth, Michael J

    2015-06-01

    Successful emergence from the soil is essential for plant establishment in natural and farmed systems. It has been assumed that the absence of light in the soil is the preeminent signal perceived during early seedling development, leading to a distinct morphogenic plan (skotomorphogenesis) [1], characterized by traits providing an adaptive advantage until emergence and photomorphogenesis. These traits include suppressed chlorophyll synthesis, promotion of hypocotyl elongation, and formation of a closed apical hook that protects the stem cell niche from damage [2, 3]. However, absence of light by itself is not a sufficient environmental signal for early seedling development [4, 5]. Reduced oxygen levels (hypoxia) can occur in water-logged soils [6-8]. We therefore hypothesized that below-ground hypoxia may be an important, but thus far undiscovered, ecological component regulating seedling development. Here, we show that survival and establishment of seedlings following darkness depend on their ability to sense hypoxia, through enhanced stability of group VII Ethylene Response Factor (ERFVII) transcription factors. Hypoxia is perceived as a positive environmental component in diverse taxa of flowering plants, promoting maintenance of skotomorphogenic traits. Hypoxia greatly enhances survival once light is perceived, while oxygen is necessary for the subsequent effective completion of photomorphogenesis. Together with light perception, oxygen sensing therefore allows an integrated response to the complex and changing physical microenvironment encountered during early seedling growth. We propose that plants monitor the soil's gaseous environment after germination, using hypoxia as a key external cue to protect the stem cell niche, thus ensuring successful rapid establishment upon emergence above ground. PMID:25981794

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

    PubMed

    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

    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

  2. Spatiotemporal Oxygen Sensing Using Dual Emissive Boron DyePolylactide Nanofibers

    PubMed Central

    2015-01-01

    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 dyepolymer 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

  3. Oxygen Sensing for Industrial Safety — Evolution and New Approaches

    PubMed Central

    Willett, Martin

    2014-01-01

    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

  4. Dissolved oxygen sensing based on fluorescence quenching of ceria nanoparticles

    NASA Astrophysics Data System (ADS)

    Shehata, Nader; Meehan, Kathleen; Leber, Donald

    2012-10-01

    The development of oxygen sensors has positively impacted the fields of medical science, bioengineering, environmental monitoring, solar cells, industrial process control, and a number of military applications. Fluorescent quenching sensors have an inherent high sensitivity, chemical selectivity, and stability when compared to other types of sensors. While cerium oxide thin films have been used to monitor oxygen in the gas phase, the potential of cerium oxide (ceria) nanoparticles as the active material in sensor for oxygen gas has only recently been investigated. Ceria nanoparticles are one of the most unique nanomaterials that are being studied today due to the diffusion and reactivity of its oxygen vacancies, which contributes to its high oxygen storage capability. The reactivity of the oxygen vacancies, which is also related to conversion of cerium ion from the Ce+4 to Ce+3 state, affects the fluorescence properties of the ceria nanoparticles. Our research demonstrates that the ceria nanoparticles (~7 nm in diameter) have application as a fluorescence quenching sensor to measure dissolved oxygen in water. We have found a strong inverse correlation between the amplitude of the fluorescence emission (?excitation = 430 nm and ?peak = 520 nm) and the dissolved oxygen concentration between 5 - 13 mg/L. The Stern-Volmer constant, which is an indication of the sensitivity of gas sensing is 184 M-1 for the ceria nanoparticles. The results show that ceria nanoparticles can be used in an improved, robust fluorescence sensor for dissolved oxygen in a liquid medium.

  5. Biosensors with modified electrodes for in vivo and ex vivo applications.

    PubMed

    Urban, G A; Jobst, G

    1997-01-01

    Integrated and miniaturized biosensor arrays were developed exhibiting outstanding performance. Biosensors with negligible sensitivity to interferences and high long-term stability were produced by modifying electrochemical transducers and utilizing photopatternable enzyme membranes. The use of appropriate miniaturization technology leads to mass producible devices for in vivo and ex vivo applications. PMID:9002203

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

    PubMed Central

    2010-01-01

    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

  7. Synthesis, structure and oxygen-sensing properties of iridium(III)-containing coordination polymers with different cations.

    PubMed

    Ho, Mei-Lin; Chen, Yi-An; Chen, Tsai-Chen; Chang, Pei-Jen; Yu, Yi-Ping; Cheng, Kum-Yi; Shih, Chien-Hung; Lee, Gene-Hsiang; Sheu, Hwo-Shuenn

    2012-03-01

    Four iridium(III)-containing coordination polymers 1-4 using Ir(ppy)(2)(H(2)dcbpy)PF(6) (L-H(2), ppy = 2-phenylpyridine, H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) as the bridging ligand, [ZnL(2)]3DMF5H(2)O (1), [CdL(2)(H(2)O)(2)]3DMF6H(2)O (2), [CoL(2)(H(2)O)(2)]2DMF8H(2)O (3) and [NiL(2)(H(2)O)(2)]3DMF6H(2)O (4), have been synthesized and structurally characterized. The emissions from 1-4 are ascribed to a metal-to-ligand charge transfer transition (MLCT). The absolute emission quantum yields for 1-4 in single crystals were measured in air to be 0.274, 0.193, 0.001 and 0.002, respectively. The noteworthy oxygen-sensing properties of 1-4 as well as L-H(2) in a single crystal were also evaluated. The Stern-Volmer quenching constant, K(SV) values, of 1-4 and L-H(2) can be deduced to be 0.834, 2.820, 1.328, 1.111 and 2.476, respectively. The results show promising K(SV) values (e.g.2) that are competitive or even larger than those of many known Ir-complexes. Moreover, the short response time (e.g. compound 2) and recovery times toward oxygen of 1-4 have been measured in their single crystal forms. The reversibility experiments for 1-4 were carried out for seven repeated cycles. As a result, >75% recovery of intensity for 1 and 2 on each cycle demonstrates a high degree of reproducibility during the sensing process. It should be noted that iridium(III)-containing coordination polymers with high emission intensity and notable oxygen sensing properties are obscure, especially in the single crystal form. This, in combination with its fine reversibility, leads to success in single crystal oxygen recognition based on photoluminescence imaging. The detection limit could be 0.50% for gaseous oxygen. Moreover, the temperature effect of compound 2 in a single crystal upon application as an oxygen sensor was expected. PMID:22222947

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

    PubMed

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

    2014-04-01

    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

  9. Natural variation in a neural globin tunes oxygen sensing in wild Caenorhabditis elegans.

    PubMed

    Persson, Annelie; Gross, Einav; Laurent, Patrick; Busch, Karl Emanuel; Bretes, Hugo; de Bono, Mario

    2009-04-23

    Behaviours evolve by iterations of natural selection, but we have few insights into the molecular and neural mechanisms involved. Here we show that some Caenorhabditis elegans wild strains switch between two foraging behaviours in response to subtle changes in ambient oxygen. This finely tuned switch is conferred by a naturally variable hexacoordinated globin, GLB-5. GLB-5 acts with the atypical soluble guanylate cyclases, which are a different type of oxygen binding protein, to tune the dynamic range of oxygen-sensing neurons close to atmospheric (21%) concentrations. Calcium imaging indicates that one group of these neurons is activated when oxygen rises towards 21%, and is inhibited as oxygen drops below 21%. The soluble guanylate cyclase GCY-35 is required for high oxygen to activate the neurons; GLB-5 provides inhibitory input when oxygen decreases below 21%. Together, these oxygen binding proteins tune neuronal and behavioural responses to a narrow oxygen concentration range close to atmospheric levels. The effect of the glb-5 gene on oxygen sensing and foraging is modified by the naturally variable neuropeptide receptor npr-1 (refs 4, 5), providing insights into how polygenic variation reshapes neural circuit function. PMID:19262507

  10. The human carotid body transcriptome with focus on oxygen sensing and inflammation--a comparative analysis.

    PubMed

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

    2012-08-15

    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

  11. Recombinant PAS-heme domains of oxygen sensing proteins: high level production and physical characterization.

    PubMed

    Suquet, Christine; Savenkova, Marina; Satterlee, James D

    2005-07-01

    Details of a high-level recombinant production method for the heme-PAS domains of heme oxygen sensing proteins from Sinorhizobium meliloti (Sm) (formerly Rhizobium meliloti, Rm), Bradyrhizobium japonicum (Bj), and Escherichia coli (Ec) are described. Using a newly proposed, concise, and unambiguous naming system (also described here) these proteins are: SmFixLH(128-264), BjFixLH(140-270), and EcDosH(1-147). In addition, high-level production of BjFixL(140-505), the soluble full-length protein containing both heme (oxygen sensing) and kinase (catalytic) domains is described. Using an IPTG-inducible pET/BL21 expression system and a rapid, two-column purification has resulted in increased yields of 3- to 17-fold over literature values. The recombinant proteins are highly pure as judged by SDS-PAGE, MALDI-TOF mass spectrometry, and a UV-visible purity index. To our knowledge, this work includes the first mass spectrometry analysis of any PAS-heme protein and provides high-resolution confirmation of each protein's identity. These production and characterization improvements make possible future spectroscopic and dynamics studies designed to elucidate the intramolecular/interdomain signal that follows heme-domain oxygen dissociation. PMID:15939306

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

    PubMed Central

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

    2012-01-01

    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

  13. Low oxygen sensing and balancing in plant seeds: a role for nitric oxide

    PubMed Central

    Borisjuk, Ljudmilla; Macherel, David; Benamar, Abdelilah; Wobus, Ulrich; Rolletschek, Hardy

    2007-01-01

    Storage product accumulation in seeds of major crop species is limited by their low internal oxygen concentration. Adjustment of energy and storage metabolism to oxygen deficiency (hypoxia) in seeds is highly relevant for agriculture and biotechnology. However, the mechanisms of low-oxygen sensing and balancing remain a mystery. Here, it is shown that normal hypoxia in seeds of soybean (Glycine max) and pea (Pisum sativum) triggers a nitrite-dependent increase in endogenous nitric oxide (NO) concentrations. NO, in turn, reduces the oxygen consumption of seeds, generating a localized decrease in both ATP availability and biosynthetic activity. Increasing oxygen availability reduces endogenous NO concentrations, thereby abolishing mitochondrial and metabolic inhibition. This auto-regulatory and reversible oxygen balancing, via NO, avoids seed anoxia and suggests a key role for NO in regulating storage activity. This hypothesis is reinforced by changes in energy status (ATP:ADP ratio), steady-state metabolite concentrations and biosynthetic fluxes under NO treatment. The proposed mechanism of low-oxygen sensing and balancing in plants offers the prospect of a new field of study in crop biotechnology. New Phytologist (2007) 176: 813823 PMID:17937762

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

    SciTech Connect

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

    2012-11-21

    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.

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

    PubMed

    Grate, Jay W; Kelly, Ryan T; Suter, Jonathan; Anheier, Norm C

    2012-11-21

    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 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 of oxygen concentration. Imaging with the opaque pillars in between the observation direction and the continuous fluorophore film yields images that retain defined spatial structure in the sensor image. PMID:22995983

  16. Handheld multispectral fluorescence lifetime imaging system for in vivo applications

    PubMed Central

    Cheng, Shuna; Cuenca, Rodrigo M.; Liu, Boang; Malik, Bilal H.; Jabbour, Joey M.; Maitland, Kristen C.; Wright, John; Cheng, Yi-Shing Lisa; Jo, Javier A.

    2014-01-01

    There is an increasing interest in the application of fluorescence lifetime imaging (FLIM) for medical diagnosis. Central to the clinical translation of FLIM technology is the development of compact and high-speed clinically compatible systems. We present a handheld probe design consisting of a small maneuverable box fitted with a rigid endoscope, capable of continuous lifetime imaging at multiple emission bands simultaneously. The system was characterized using standard fluorescent dyes. The performance was then further demonstrated by imaging a hamster cheek pouch in vivo, and oral mucosa tissue both ex vivo and in vivo, all using safe and permissible exposure levels. Such a design can greatly facilitate the evaluation of FLIM for oral cancer imaging in vivo. PMID:24688824

  17. Application of in vivo laser scanning microscope in dermatology

    NASA Astrophysics Data System (ADS)

    Lademann, Juergen; Richter, H.; Otberg, N.; Lawrenz, F.; Blume-Peytavi, U.; Sterry, W.

    2003-10-01

    The state of the art of in-vivo and in-vitro penetration measurements of topically applied substances is described. Only optical techniques represent online measuring methods based on the absorption or scattering properties of the topically applied substances. Laser scanning microscopy (LSM) has become a promising method for investigations in dermatology and skin physiology, after it was possible to analyze the skin surface on any body side in-vivo. In the present paper the application of a dermatological laser scanning microscope for penetration and distribution measurements of topically applied substances is described. The intercellular and follicular penetration pathways were studied.

  18. Optical oxygen-sensing properties of porphyrin derivatives anchored on ordered porous aluminium oxide plates.

    PubMed

    Araki, Naoko; Amao, Yutaka; Funabiki, Takuzo; Kamitakahara, Masanobu; Ohtsuki, Chikara; Mitsuo, Kazunori; Asai, Keisuke; Obata, Makoto; Yano, Shigenobu

    2007-07-01

    An optical oxygen-sensing activity of anchored porphyrin derivatives on ordered porous aluminium oxide plates was studied in relevance to development of new oxygen-sensing systems. Porphyrin derivatives, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrin, 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrin, 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrin, and their platinum complexes, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrinatoplatinum(II), 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrinatoplatinum(II), 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrinatoplatinum(II), were synthesized and anchored by an equilibrium adsorption method on aluminium oxide plates, which were prepared by an anodic oxidation. The excitation spectra of the porphyrin-anchored layers showed a broadened and blue-shifted Soret band compared with the corresponding porphyrins in DMSO. The luminescence intensity decreased with increasing oxygen concentrations. The oxygen-sensing ability estimated from I(0)/I(100) (I(0) and I(100) denote the luminescence intensity in 0 and 100% oxygen) was 9.08, 6.78, 8.71, 81.9, 35.5, and 39.1, which are greater than those of corresponding porphyrin derivatives in DMSO under the measured conditions, and indicates the remarkable enhancement effect of platinum(II). Non-linear Stern-Volmer plots were well fitted by the two component system to give the oxygen-sensitive constant (K(SV1)/%(-1)), the oxygen-insensitive constant (K(SV2)/%(-1)), and the former contribution (f(1)): 0.232, 3.32 x 10(-2), and 0.642; 0.141, 2.05 x 10(-2), and 0.687; 0.143, 1.05 x 10(-2), and 0.882; 17.3, 7.04 x 10(-3), and 0.980; 10.2, 1.43 x 10(-2), and 0.935; 16.3, 8.35 x 10(-3), and 0.954. The response time for the change of the atmospheric gas from argon to oxygen was 9.4 s, 12.5 s, 9.6 s, 5.0 s, 8.9 s, and 4.6 s, indicating the shortening effect of platinum. The reverse effect of platinum was observed in the change from oxygen to argon: 15.5 s, 17.0 s, 20.8 s, 667.4 s, 590.1 s, and 580.4 s, indicating the specific interaction of oxygen to the platinum(II) center. PMID:17609774

  19. Biodegradable luminescent porous silicon nanoparticles for in vivo applications

    NASA Astrophysics Data System (ADS)

    Park, Ji-Ho; Gu, Luo; von Maltzahn, Geoffrey; Ruoslahti, Erkki; Bhatia, Sangeeta N.; Sailor, Michael J.

    2009-04-01

    Nanomaterials that can circulate in the body hold great potential to diagnose and treat disease. For such applications, it is important that the nanomaterials be harmlessly eliminated from the body in a reasonable period of time after they carry out their diagnostic or therapeutic function. Despite efforts to improve their targeting efficiency, significant quantities of systemically administered nanomaterials are cleared by the mononuclear phagocytic system before finding their targets, increasing the likelihood of unintended acute or chronic toxicity. However, there has been little effort to engineer the self-destruction of errant nanoparticles into non-toxic, systemically eliminated products. Here, we present luminescent porous silicon nanoparticles (LPSiNPs) that can carry a drug payload and of which the intrinsic near-infrared photoluminescence enables monitoring of both accumulation and degradation in vivo. Furthermore, in contrast to most optically active nanomaterials (carbon nanotubes, gold nanoparticles and quantum dots), LPSiNPs self-destruct in a mouse model into renally cleared components in a relatively short period of time with no evidence of toxicity. As a preliminary in vivo application, we demonstrate tumour imaging using dextran-coated LPSiNPs (D-LPSiNPs). These results demonstrate a new type of multifunctional nanostructure with a low-toxicity degradation pathway for in vivo applications.

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

    SciTech Connect

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

    2006-01-01

    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.

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

    PubMed

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

    2015-01-01

    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. PMID:25082441

  2. Oxygen-sensing PHDs regulate bone homeostasis through the modulation of osteoprotegerin

    PubMed Central

    Wu, Colleen; Rankin, Erinn B.; Castellini, Laura; Fernandez-Alcudia, Javier; LaGory, Edward L.; Andersen, Rebecca; Rhodes, Steven D.; Wilson, Tremika L.S.; Mohammad, Khalid S.; Castillo, Alesha B.; Guise, Theresa A.; Schipani, Ernestina

    2015-01-01

    The bone microenvironment is composed of niches that house cells across variable oxygen tensions. However, the contribution of oxygen gradients in regulating bone and blood homeostasis remains unknown. Here, we generated mice with either single or combined genetic inactivation of the critical oxygen-sensing prolyl hydroxylase (PHD) enzymes (PHD13) in osteoprogenitors. Hypoxia-inducible factor (HIF) activation associated with Phd2 and Phd3 inactivation drove bone accumulation by modulating osteoblastic/osteoclastic cross-talk through the direct regulation of osteoprotegerin (OPG). In contrast, combined inactivation of Phd1, Phd2, and Phd3 resulted in extreme HIF signaling, leading to polycythemia and excessive bone accumulation by overstimulating angiogenicosteogenic coupling. We also demonstrate that genetic ablation of Phd2 and Phd3 was sufficient to protect ovariectomized mice against bone loss without disrupting hematopoietic homeostasis. Importantly, we identify OPG as a HIF target gene capable of directing osteoblast-mediated osteoclastogenesis to regulate bone homeostasis. Here, we show that coordinated activation of specific PHD isoforms fine-tunes the osteoblastic response to hypoxia, thereby directing two important aspects of bone physiology: cross-talk between osteoblasts and osteoclasts and angiogenicosteogenic coupling. PMID:25846796

  3. Reversed oxygen sensing using colloidal quantum wells towards highly emissive photoresponsive varnishes

    NASA Astrophysics Data System (ADS)

    Lorenzon, Monica; Christodoulou, Sotirios; Vaccaro, Gianfranco; Pedrini, Jacopo; Meinardi, Francesco; Moreels, Iwan; Brovelli, Sergio

    2015-03-01

    Colloidal quantum wells combine the advantages of size-tunable electronic properties with vast reactive surfaces that could allow one to realize highly emissive luminescent-sensing varnishes capable of detecting chemical agents through their reversible emission response, with great potential impact on life sciences, environmental monitoring, defence and aerospace engineering. Here we combine spectroelectrochemical measurements and spectroscopic studies in a controlled atmosphere to demonstrate the reversed oxygen-sensing capability of CdSe colloidal quantum wells, that is, the exposure to oxygen reversibly increases their luminescence efficiency. Spectroelectrochemical experiments allow us to directly relate the sensing response to the occupancy of surface states. Magneto-optical measurements demonstrate that, under vacuum, heterostructured CdSe/CdS colloidal quantum wells stabilize in their negative trion state. The high starting emission efficiency provides a possible means to enhance the oxygen sensitivity by partially de-passivating the particle surfaces, thereby enhancing the density of unsaturated sites with a minimal cost in term of luminescence losses.

  4. Thickness Dependency of Thin Film Samaria Doped Ceria for Oxygen Sensing

    SciTech Connect

    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

    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.

  5. Diversity of Magneto-Aerotactic Behaviors and Oxygen Sensing Mechanisms in Cultured Magnetotactic Bacteria

    PubMed Central

    Lefèvre, Christopher T.; Bennet, Mathieu; Landau, Livnat; Vach, Peter; Pignol, David; Bazylinski, Dennis A.; Frankel, Richard B.; Klumpp, Stefan; Faivre, Damien

    2014-01-01

    Microorganisms living in gradient environments affect large-scale processes, including the cycling of elements such as carbon, nitrogen or sulfur, the rates and fate of primary production, and the generation of climatically active gases. Aerotaxis is a common adaptation in organisms living in the oxygen gradients of stratified environments. Magnetotactic bacteria are such gradient-inhabiting organisms that have a specific type of aerotaxis that allows them to compete at the oxic-anoxic interface. They biomineralize magnetosomes, intracellular membrane-coated magnetic nanoparticles, that comprise a permanent magnetic dipole that causes the cells to align along magnetic field lines. The magnetic alignment enables them to efficiently migrate toward an optimal oxygen concentration in microaerobic niches. This phenomenon is known as magneto-aerotaxis. Magneto-aerotaxis has only been characterized in a limited number of available cultured strains. In this work, we characterize the magneto-aerotactic behavior of 12 magnetotactic bacteria with various morphologies, phylogenies, physiologies, and flagellar apparatus. We report six different magneto-aerotactic behaviors that can be described as a combination of three distinct mechanisms, including the reported (di-)polar, axial, and a previously undescribed mechanism we named unipolar. We implement a model suggesting that the three magneto-aerotactic mechanisms are related to distinct oxygen sensing mechanisms that regulate the direction of cells’ motility in an oxygen gradient. PMID:25028894

  6. Oxygen sensing and signaling: impact on the regulation of physiologically important genes

    PubMed Central

    Zhu, Hao; Bunn, H. Franklin

    2011-01-01

    A growing number of physiologically relevant genes are regulated in response to changes in intracellular oxygen tension. It is likely that cells from a wide variety of tissues share a common mechanism of oxygen sensing and signal transduction leading to the activation of the transcription factor hypoxia-inducible factor 1 (HIF-1). Besides hypoxia, transition metals (Co2+, Ni2+ and Mn2+) and iron chelation also promote activation of HIF-1. Induction of HIF-1 by hypoxia is blocked by the heme ligands carbon monoxide and nitric oxide. There is growing, albeit indirect, evidence that the oxygen sensor is a flavoheme protein and that the signal transduction pathway involves changes in the level of intracellular reactive oxygen intermediates. The activation of HIF-1 by hypoxia depends upon signaling-dependent rescue of its ?-subunit from oxygen-dependent degradation in the proteasome, allowing it to form a heterodimer with HIF-1? (ARNT), which then translocates to the nucleus and impacts on the transcription of genes whose cis-acting elements contain cognate hypoxia response elements. PMID:10385037

  7. Clinical applications of in vivo fluorescence confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Oh, Chilhwan; Park, Sangyong; Kim, Junhyung; Ha, Seunghan; Park, Gyuman; Lee, Gunwoo; Lee, Onseok; Chun, Byungseon; Gweon, Daegab

    2008-02-01

    Living skin for basic and clinical research can be evaluated by Confocal Laser Scanning Microscope (CLSM) non-invasively. CLSM imaging system can achieve skin image its native state either "in vivo" or "fresh biopsy (ex vivo)" without fixation, sectioning and staining that is necessary for routine histology. This study examines the potential fluorescent CLSM with a various exogenous fluorescent contrast agent, to provide with more resolution images in skin. In addition, in vivo fluorescent CLSM researchers will be extended a range of potential clinical application. The prototype of our CLSM system has been developed by Prof. Gweon's group. The operating parameters are composed of some units, such as illuminated wavelength 488 nm, argon illumination power up to 20mW on the skin, objective lens, 0.9NA oil immersion, axial resolution 1.0μm, field of view 200μm x 100μm (lateral resolution , 0.3μm). In human volunteer, fluorescein sodium was administrated topically and intradermally. Animal studies were done in GFP transgenic mouse, IRC mouse and pig skin. For imaging of animal skin, fluorescein sodium, acridine orange, and curcumine were used for fluorescein contrast agent. We also used the GFP transgenic mouse for fluorescein CLSM imaging. In intact skin, absorption of fluorescein sodium by individual corneocyte and hair. Intradermal administrated the fluorescein sodium, distinct outline of keratinocyte cell border could be seen. Curcumin is a yellow food dye that has similar fluorescent properties to fluorescein sodium. Acridin Orange can be highlight nuclei in viable keratinocyte. In vivo CLSM of transgenic GFP mouse enable on in vivo, high resolution view of GFP expressing skin tissue. GFP signals are brightest in corneocyte, kertinocyte, hair and eccrine gland. In intact skin, absorption of fluorescein sodium by individual corneocyte and hair. Intradermal administrated the fluorescein sodium, distinct outline of keratinocyte cell border could be seen. In papillary dermis, fluorescein distribution is more homogeneous. Curcumin is a yellow food dye that has similar fluorescent properties to fluorescein sodium. In vivo CLSM of transgenic GFP mouse enable on in vivo, high resolution view of GFP expressing skin tissue. GFP signals are brightest in corneocyte, kertinocyte, skin appendage and blood vessels. In conclusion, this study demonstrates the usefulness of CLSM as technique for imaging skin in vivo. In addition, CLSM is non-invasive, the same tissue site may be imaged over a period of time to monitor the various change such as wound healing, severity of skin diseases and effect of therapeutic management.

  8. Applications of nuclear technologies for in-vivo elemental analysis

    SciTech Connect

    Cohn, S.H.; Ellis, K.J.; Vartsky, D.; Wielopolski, L.

    1982-01-01

    Measurement facilities developed, to date, include a unique whole-body-counter, (WBC); a total-body neutron-activation facility (TBNAA); and a partial-body activation facility (PBNAA). A variation of the prompt-gamma neutron-activation technique for measuring total-body nitrogen was developed to study body composition of cancer patients and the effect of nutritional regimens on the composition. These new techniques provide data in numerous clinical studies not previously amenable to investigation. The development and perfection of these techniques provide unique applications of radiation and radioisotopes to the early diagnosis of certain diseases and the evaluation of therapeutic programs. The PBNAA technique has been developed and calibrated for in-vivo measurement of metals. Development has gone forward on prompt-gamma neutron activation for the measurement of cadmium, x-ray fluorescence (XRF) for measurement of iron. Other techniques are being investigated for in-vivo measurement of metals such as silicon and beryllium.

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

    SciTech Connect

    Zhou Minghua . E-mail: mzhou@nrcan.gc.ca; Ahmad, Aftab

    2006-04-13

    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.

  10. Vertically integrated human P450 and oxygen sensing film for the assays of P450 metabolic activities.

    PubMed

    Chang, Gang; Morigaki, Kenichi; Tatsu, Yoshiro; Hikawa, Takashi; Goto, Tatsushi; Imaishi, Hiromasa

    2011-04-15

    An assaying method of cytochrome P450 (P450 or CYP) monooxygenase activities for toxicological evaluation of drugs and environmental pollutants was developed by immobilizing P450 on an oxygen sensoring layer. Membrane fractions from E. coli expressing human P450 were entrapped in agarose or silica-based gels and immobilized on 96-well microarrays having an oxygen sensing film at the bottom. The oxygen sensing film was made of an organically modified silica film (ORMOSIL) doped with Tris(4,7-diphenyl-1,10-phenanthroline) ruthenium dichloride (Ru(dpp)(3)Cl(2)). P450 activity toward the substrates was monitored through the fluorescence intensity enhancement due to the oxygen consumption by the metabolic reactions. For the metabolism of chlortoluron, a selective herbicide used to control grass weeds, CYP1A1 immobilized in agarose gel showed a higher activity and stability compared with those in silica gels and free suspensions. The luminescence changing rate evaluated by the dynamic transient method (DTM) could be correlated with the substrate concentration. We also compared the metabolic responses of human P450s (CYP1A1,CYP2C8, CYP2E1, CYP3A4) toward various substances. The use of immobilized P450 on an oxygen sensing layer provides a versatile assaying platform owing to the following features. First, the oxygen sensor can detect metabolic reactions of any P450 species, in contrast with assays using fluorogenic substrates. Second, vertical integration of the oxygen sensor and immobilized P450 enhanced the sensitivity because of the effective depletion of oxygen in the vicinity of the oxygen sensing layer. Third, immobilization enables repeated use of P450 by replacing the substrate solutions using a flow cell. Furthermore, the activity of immobilized P450 was retained at least for 3 weeks at 4 C, suggesting its long-term stability, which is an additional attractive feature. PMID:21434664

  11. GAVA: Spectral Simulation for In Vivo MRS Applications

    PubMed Central

    Soher, Brian J.; Young, Karl; Bernstein, Aaron; Aygula, Zakaria; Maudsley, Andrew A.

    2007-01-01

    An application that provides a flexible and easy to use interface to the GAMMA spectral simulation package is described that is targeted at investigations using in vivo MR spectroscopic methods. The program makes available a number of widely used spatially-localized MRS pulse sequences and NMR parameters for commonly-observed tissue metabolites, enabling spectra to be simulated for any pulse sequence parameter and viewed in an integrated display. The application is interfaced with a database for storage of all simulation parameters and results of the simulations. This application provides a convenient method for generating a priori spectral information used in parametric spectral analyses and for visual examination of the effects of difference pulse sequences and parameter settings. PMID:17257868

  12. Microwave applicator for hyperthermia treatment on in vivo melanoma model.

    PubMed

    Togni, Paolo; Vrba, Jan; Vannucci, Luca

    2010-03-01

    In this article, we evaluated a planar microwave applicator for in vivo superficial hyperthermia treatments on small tumors in the mouse mimicking treatments for human neoplasms. The design of the applicator, was challenged by the small dimensions of the tumors and unwanted diffusion of heating in the tumor-bearing animals. The required solution was to limit the penetration of microwaves in the depth of the tissue maintaining the full efficacy of hyperthermia. The study was firstly performed by computer simulations of SAR distribution inside a flat homogeneous phantom, considering various thicknesses of the integrated water bolus. Simulations, validated by the measurements, were also used to evaluate the impedance matching. Further tests were performed on homogeneous agar phantom to simulate the temperature distribution in the biological tissue and to preliminary assess the possible modality and schedule of microwave hyperthermia delivery. The in vivo experiments showed the evidence of direct microwave-induced heating and damage of the melanoma tissue in a range of penetration coherent both with computer simulations and phantom studies. The described approach appears perspective for designing limited-microwave-delivery applicators tailored for treatments of human superficial tumors and pre-tumoral lesions. PMID:20033789

  13. In vitro - in vivo correlation: from theory to applications.

    PubMed

    Emami, Jaber

    2006-01-01

    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 vitro and in vivo drug release data has exceedingly increased. Such a tool shortens the drug development period, economizes the resources and leads to improved product quality. Increased activity in developing IVIVCs indicates the value of IVIVCs to the pharmaceutical industry. IVIVC can be used in the development of new pharmaceuticals to reduce the number of human studies during the formulation development as the main objective of an IVIVC is to serve as a surrogate for in vivo bioavailability and to support biowaivers. It supports and/or validates the use of dissolution methods and specification settings. This is because the IVIVC includes in vivo relevance to in vitro dissolution specifications. It can also assist in quality control for certain scale-up and post-approval changes (SUPAC). With the proliferation of modified-release products, it becomes necessary to examine the concept of IVIVC in greater depth. Investigations of IVIVC are increasingly becoming an integral part of extended release drug development. There must be some in vitro means of assuring that each batch of the same product will perform identically in vivo. This review article represents the FDA guidance, development, evaluation, and validation of an IVIVC to grant biowaivers, and to set dissolution specifications for oral dosage forms, biopharmaceutics classification systems (BCS), BCS biowaivers, application of BCS in IVIVC development and concept of mapping. The importance of dissolution media and methodology and pharmacokinetic studies in the context of IVIVC has been highlighted. The review also covers the literature examples of IVIVCs regarding internal and external validation, compendial dissolution assessment, formulation dependency of IVIVCs, and IVIVCs of pure enantiomers versus racemate drugs. The same principles of IVIVC used for oral extended release products may be applied for non-oral products such as parenteral depot formulations and novel drug delivery systems as well. PMID:16959187

  14. In vivo Coherent Raman Imaging for Neuroscience Applications

    NASA Astrophysics Data System (ADS)

    Cote, Daniel

    2010-08-01

    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.

  15. Therapeutic targeting of oxygen-sensing prolyl hydroxylases abrogates ATF4-dependent neuronal death and improves outcomes after brain hemorrhage in several rodent models.

    PubMed

    Karuppagounder, Saravanan S; Alim, Ishraq; Khim, Soah J; Bourassa, Megan W; Sleiman, Sama F; John, Roseleen; Thinnes, Cyrille C; Yeh, Tzu-Lan; Demetriades, Marina; Neitemeier, Sandra; Cruz, Dana; Gazaryan, Irina; Killilea, David W; Morgenstern, Lewis; Xi, Guohua; Keep, Richard F; Schallert, Timothy; Tappero, Ryan V; Zhong, Jian; Cho, Sunghee; Maxfield, Frederick R; Holman, Theodore R; Culmsee, Carsten; Fong, Guo-Hua; Su, Yijing; Ming, Guo-Li; Song, Hongjun; Cave, John W; Schofield, Christopher J; Colbourne, Frederick; Coppola, Giovanni; Ratan, Rajiv R

    2016-03-01

    Disability or death due to intracerebral hemorrhage (ICH) is attributed to blood lysis, liberation of iron, and consequent oxidative stress. Iron chelators bind to free iron and prevent neuronal death induced by oxidative stress and disability due to ICH, but the mechanisms for this effect remain unclear. We show that the hypoxia-inducible factor prolyl hydroxylase domain (HIF-PHD) family of iron-dependent, oxygen-sensing enzymes are effectors of iron chelation. Molecular reduction of the three HIF-PHD enzyme isoforms in the mouse striatum improved functional recovery after ICH. A low-molecular-weight hydroxyquinoline inhibitor of the HIF-PHD enzymes, adaptaquin, reduced neuronal death and behavioral deficits after ICH in several rodent models without affecting total iron or zinc distribution in the brain. Unexpectedly, protection from oxidative death in vitro or from ICH in vivo by adaptaquin was associated with suppression of activity of the prodeath factor ATF4 rather than activation of an HIF-dependent prosurvival pathway. Together, these findings demonstrate that brain-specific inactivation of the HIF-PHD metalloenzymes with the blood-brain barrier-permeable inhibitor adaptaquin can improve functional outcomes after ICH in several rodent models. PMID:26936506

  16. Engineered biocompatible nanoparticles for in vivo imaging applications.

    PubMed

    Chen, Shu; Wang, Lijun; Duce, Suzanne L; Brown, Stuart; Lee, Stephen; Melzer, Andreas; Cuschieri, Alfred; Andr, Pascal

    2010-10-27

    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

  17. Plant oxygen sensing is mediated by the N-end rule pathway: a milestone in plant anaerobiosis.

    PubMed

    Sasidharan, Rashmi; Mustroph, Angelika

    2011-12-01

    Like all aerobic organisms, plants require molecular oxygen for respiratory energy production. In plants, hypoxic conditions can occur during natural events (e.g., flooding), during developmental processes (e.g., seed germination), and in cells of compact tissues with high metabolic rates. Plant acclimation responses to hypoxia involve a modulation of gene expression leading to various biochemical, physiological, and morphological changes that stave off eventual anoxia. In contrast with the animal kingdom, a direct oxygen-sensing mechanism in plants has been elusive so far. However, two recent independent studies show that oxygen sensing in plants operates via posttranslational regulation of key hypoxia response transcription factors by the N-end rule pathway. The N-end rule is an evolutionarily conserved pathway for protein degradation that relates the fate of a protein with the identity of its N-terminal residues. Results from these studies demonstrate that oxygen-dependent modification and targeted proteolysis of members of the ethylene response factor group VII transcription factor family regulate hypoxia-responsive gene expression in Arabidopsis thaliana. The discovery of this plant hypoxia-sensing mechanism sets the stage for further research on plant homeostatic response to oxygen, which could be relevant to understanding plant distributions in flood-prone ecosystems and improving hypoxia tolerance of crops. PMID:22207573

  18. Plant Oxygen Sensing Is Mediated by the N-End Rule Pathway: A Milestone in Plant Anaerobiosis

    PubMed Central

    Sasidharan, Rashmi; Mustroph, Angelika

    2011-01-01

    Like all aerobic organisms, plants require molecular oxygen for respiratory energy production. In plants, hypoxic conditions can occur during natural events (e.g., flooding), during developmental processes (e.g., seed germination), and in cells of compact tissues with high metabolic rates. Plant acclimation responses to hypoxia involve a modulation of gene expression leading to various biochemical, physiological, and morphological changes that stave off eventual anoxia. In contrast with the animal kingdom, a direct oxygen-sensing mechanism in plants has been elusive so far. However, two recent independent studies show that oxygen sensing in plants operates via posttranslational regulation of key hypoxia response transcription factors by the N-end rule pathway. The N-end rule is an evolutionarily conserved pathway for protein degradation that relates the fate of a protein with the identity of its N-terminal residues. Results from these studies demonstrate that oxygen-dependent modification and targeted proteolysis of members of the ethylene response factor group VII transcription factor family regulate hypoxia-responsive gene expression in Arabidopsis thaliana. The discovery of this plant hypoxia-sensing mechanism sets the stage for further research on plant homeostatic response to oxygen, which could be relevant to understanding plant distributions in flood-prone ecosystems and improving hypoxia tolerance of crops. PMID:22207573

  19. Sol-gel-Derived highly sensitive optical oxygen sensing materials using Ru(II) complex via covalent grafting strategy.

    PubMed

    Zhang, Haoran; Lei, Bingfu; Liu, Yingliang; Liu, Xiaotang; Zheng, Mingtao; Dong, Hanwu; Xiao, Yong; Zhang, Jianying

    2014-06-01

    The preparation and oxygen sensing properties of Ru(ll) covalently-grafted and physically-incorporated silica based hybrid materials by sol-gel technique are described in this article. The Ru(II) complexes are successfully grafted onto the backbone of the silica via the condensation reaction of the tetraethoxysilane and the functionalized Ru(II) complex 2-[4'-{3-(Triethoxysilyl)propyl}phenyl]imidazo [4,5-f]-1,10-phenanthroline that contains the hydrolysable tri-alkoxylsilyl group. The luminescence quenching of Ru(II) complex by oxygen within the silica matrix is efficient. The oxygen quenching sensitivity of the covalently-grafted sample is higher than that of the physically-incorporated one due to the strong Si-CH2 bond that is useful to prolong the excited state lifetimes and enhance the photobleaching of the luminophore. The downward oxygen sensing Stern-Volmer plots can be well fitted using the Demas two-site model and the Lehrer model due to the heterogeneous distribution of the Ru(ll) complex within the sol-gel derived silica. PMID:24738438

  20. Click-assembled, oxygen sensing nanoconjugates for depth-resolved, near-infrared imaging in a 3D cancer model

    PubMed Central

    Nichols, Alexander J.; Roussakis, Emmanuel; Klein, Oliver J.

    2014-01-01

    Hypoxia is an important factor that contributes to the development of drug-resistant cancer, yet few non-perturbative tools exist for studying oxygen in tissue. While progress has been made in the development of chemical probes for optical oxygen mapping, penetration into poorly perfused or avascular tumor regions remains problematic. Here we report a Click-Assembled Oxygen Sensing (CAOS) nanoconjugate and demonstrate its properties in an in vitro 3D spheroid cancer model. Our synthesis relies on sequential click-based ligation of poly(amidoamine)-like subunits for rapid assembly. Using near-infrared confocal phosphorescence microscopy, we demonstrate the ability of CAOS nanoconjugates to penetrate hundreds of microns into spheroids within hours and show their sensitivity to oxygen changes throughout the nodule. This proof-of-concept study demonstrates a modular approach that is readily extensible to a wide variety of oxygen and cellular sensors for depth-resolved imaging in tissue and tissue models. PMID:24590700

  1. Redox-sensitive transient receptor potential channels in oxygen sensing and adaptation.

    PubMed

    Mori, Yasuo; Takahashi, Nobuaki; Polat, Onur Kerem; Kurokawa, Tatsuki; Takeda, Norihiko; Inoue, Masahiro

    2016-01-01

    Regulation of ion channels is central to the mechanisms that underlie immediate acute physiological responses to changes in the availability of molecular oxygen (O2). A group of cation-permeable channels that are formed by transient receptor potential (TRP) proteins have been characterized as exquisite sensors of redox reactive species and as efficient actuators of electric/ionic signals in vivo. In this review, we first discuss how redox-sensitive TRP channels such as TRPA1 have recently emerged as sensors of the relatively inert oxidant O2. With regard to the physiological significance of O2 sensor TRP channels, vagal TRPA1 channels are mainly discussed with respect to their role in respiratory regulation in comparison with canonical pathways in glomus cells of the carotid body, which is a well-established O2-sensing organ. TRPM7 channels are discussed regarding hypoxia-sensing function in ischemic cell death. Also, ubiquitous expression of TRPA1 and TRPM7 together with their physiological relevance in the body is examined. Finally, based upon these studies on TRP channels, we propose a hypothesis of "O2 remodeling." The hypothesis is that cells detect deviation of O2 availability from appropriate levels via sensors and adjust local O2 environments in vivo by controlling supply and consumption of O2 via pathways comprising cellular signals and transcription factors downstream of sensors, which consequently optimize physiological functions. This new insight into O2 adaptation through ion channels, particularly TRPs, may foster a paradigm shift in our understanding in the biological significance of O2. PMID:26149285

  2. 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)

    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

    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.

  3. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

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

    2004-10-01

    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. High temperature measurements of the emission of clusters in sol gel films show that the luminescence intensity from the films follow a 1/T relationship from room temperature to 150 C, and then declines at a slower rate at higher temperatures. The large number of photons available at 230 C is consistent with simple low cost optics for fiber optic probes based on the emission from clusters in sol gel films.

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

    PubMed Central

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

    2012-01-01

    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

  5. Nanoscale Metal-Organic Frameworks for Ratiometric Oxygen Sensing in Live Cells.

    PubMed

    Xu, Ruoyu; Wang, Youfu; Duan, Xiaopin; Lu, Kuangda; Micheroni, Daniel; Hu, Aiguo; Lin, Wenbin

    2016-02-24

    We report the design of a phosphorescence/fluorescence dual-emissive nanoscale metal-organic framework (NMOF), R-UiO, as an intracellular oxygen (O2) sensor. R-UiO contains a Pt(II)-porphyrin ligand as an O2-sensitive probe and a Rhodamine-B isothiocyanate ligand as an O2-insensitive reference probe. It exhibits good crystallinity, high stability, and excellent ratiometric luminescence response to O2 partial pressure. In vitro experiments confirmed the applicability of R-UiO as an intracellular O2 biosensor. This work is the first report of a NMOF-based intracellular oxygen sensor and should inspire the design of ratiometric NMOF sensors for other important analytes in biological systems. PMID:26864385

  6. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

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

    2006-09-30

    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. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. Due to the improved mechanical properties of this approach high temperature sensor measurements were performed up to 100 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  7. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

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

    2006-06-30

    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. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. This particle-in-binder approach affords fibers with greatly improved mechanical properties, as compared to previous approaches. The sensor was characterized in 2-21% gas phase oxygen at 40, 70 and 100 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  8. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

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

    2004-07-01

    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. Alkali salts of Mo{sub 6}Cl{sub 12} were synthesized and heated to 280 C for one hour in air. Optical measurements of the thermally treated material confirm the potential of the salts as lumophores in high temperature fiber optic sensors. In addition sol-gel films containing Mo{sub 6}Cl{sub 12} were dip coated on quartz substrates and heated at 200 C for one hour. Conditions were developed for successfully immobilizing monomeric complexes that are compatible with sol-gel processing.

  9. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

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

    2006-09-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications has been developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. We report on a fiber optic technique for detection of gas phase oxygen up to 100 C based on the {sup 3}O{sub 2} quenching of the luminescence from molybdenum chloride clusters, K{sub 2}Mo{sub 6}Cl{sub 14}. The inorganic sensing film is a composite of sol-gel particles embedded in a thin, oxygen permeable sol-gel binder. The particles are comprised of thermally stable, luminescent K{sub 2}Mo{sub 6}Cl{sub 14} clusters dispersed in a fully equilibrated sol-gel matrix. From 40 to 100 C, the fiber sensor switches {approx}6x in intensity in response to alternating pulses of <0.001% O2 and 21% O{sub 2} between two well defined levels with a response time of 10 s. The sensor signal is a few nW for an input pump power of 250 {micro}W. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, sensitivity at 100 C is 160 [O{sub 2}]{sup -1}. These parameters are well suited for in-situ, real-time monitoring of oxygen for industrial process control applications.

  10. Study on a phosphorescent copper(I) complex and its oxygen-sensing performances upon polystyrene and MCM-41 matrixes.

    PubMed

    Xu, Xiao-yong; Xiao, Han-ning; Xu, Yi-ming; Zhang, Ming-jun

    2012-09-01

    In this paper, we synthesize a new ligand of 1-ethyl-2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (Phen-Np-Et) and its corresponding Cu(I) complex of [Cu(Phen-Np-Et)(POP)]BF(4), where POP is bis(2-(diphenylphosphanyl)phenyl) ether. The single-crystal structure, electronic nature and photophysical property of [Cu(Phen-Np-Et)(POP)]BF(4) are discussed in detail. It is found that the yellow emission from [Cu(Phen-Np-Et)(POP)]BF(4) owns a long excited state lifetime of 287 ?s under pure N(2) atmosphere. Theoretical calculation on [Cu(Phen-Np-Et)(POP)](+) suggests that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. Then, [Cu(Phen-Np-Et)(POP)]BF(4) are doped into two matrixes of polystyrene and MCM-41 to investigate the oxygen-sensing performance. Finally, sensitivity maxima of 9.6 and 3.6 are achieved by the composite nanofibers of [Cu(Phen-Np-Et)(POP)]BF(4)/polystyrene and the [Cu(Phen-Np-Et)(POP)]BF(4)/MCM-41, respectively. Both samples are highly sensitive toward molecular oxygen, owing to the large surface-area-to-volume ratios of nanofibrous membranes and MCM-41 matrix. PMID:22580147

  11. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

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

    2004-04-01

    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. The luminescence of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix was measured as a function of heater temperature up to 200 C, in an inert environment. While the luminescence decreased with temperature, the integrated intensity at 200 C should be sufficient to enable detection of the luminescence in a fiber geometry. Previously we found that aging Mo{sub 6}Cl{sub 12} at temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Optical and thermal aging experiments show that the alkali metal salts of Mo{sub 6}Cl{sub 12} have higher thermal stabilities and remain luminescent after aging at 280 C.

  12. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

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

    2005-04-01

    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. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potassium salt of the molybdenum clusters, K{sub 2}Mo{sub 6}Cl{sub 14}, we have established the conditions necessary for deposition of optical quality sol-gel films. From spectroscopic measurements of the film we have shown that the cluster luminescence is stable following heat cycling of 54 hours at 200 C. Quenching of a factor of 1.5X between pure nitrogen and 21% oxygen was observed from in-situ measurements of films heated directly at 200 C. An automated system for characterizing fiber optic oxygen sensors up to 220 C with a temporal resolution better than 10 s is under construction. We estimate a signal of 6 x 10{sup 8} photons/s after complete quenching in 21% oxygen. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  13. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

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

    2005-07-01

    A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the cluster's ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K{sub 2}Mo{sub 6}Cl{sub 14}) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175 C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection.

  14. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

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

    2005-01-01

    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. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potassium salt of the molybdenum clusters, K{sub 2}Mo{sub 6}Cl{sub 14}, we have established the conditions necessary for deposition of optical quality sol-gel films. From spectroscopic measurements of the film we have shown that the cluster luminescence is stable following heat cycling of 1 hour at 250 C. Quenching of a factor of 4X between pure nitrogen and 21% oxygen was observed for films cured directly at 200 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  15. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

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

    2006-05-01

    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 the 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. The response of the sensor to oxygen at 40, 70 and 100 C was measured in 2-21% gas phase oxygen. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, at 100 C the sensitivity is 160 [O{sub 2}]{sup -1}. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  16. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

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

    2006-01-01

    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.

  17. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

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

    2003-07-01

    Mo{sub 6}Cl{sub 12}, a cluster compound whose luminescence depends on the ambient concentration of oxygen, is the basis for a real-time oxygen sensor for combustion applications. Previously, the properties of Mo{sub 6}Cl{sub 12} have largely been studied at room temperature; these studies have now been extended to 200 C. Optical microscopy shows that Mo{sub 6}Cl{sub 12} undergoes a steady change in color as it is heated from room temperature to 200 C, changing from canary yellow to crimson and then back to canary yellow. Concurrent thermal gravimetric analyses show a small weight loss for Mo{sub 6}Cl{sub 12} that is consistent with loss of water or HCl from the clusters. These changes are reversible. Absorption and fluorescence emission spectroscopy of Mo{sub 6}Cl{sub 12} heated to 200 C for two hours shows no change in the photophysical parameters compared to the control sample that was not heat cycled.

  18. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

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

    2005-10-01

    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.

  19. Full-field OCT: ex vivo and in vivo biological imaging applications

    NASA Astrophysics Data System (ADS)

    Grieve, Katharine; Dubois, Arnaud; Moneron, Gael; Guyot, Elvire; Boccara, Albert C.

    2005-04-01

    We present results of studies in embryology and ophthalmology performed using our ultrahigh-resolution full-field OCT system. We also discuss recent developments to our ultrashort acquisition time full-field optical coherence tomography system designed to allow in vivo biological imaging. Preliminary results of high-speed imaging in biological samples are presented. The core of the experimental setup is the Linnik interferometer, illuminated by a white light source. En face tomographic images are obtained in real-time without scanning by computing the difference of two phase-opposed interferometric images recorded by high-resolution CCD cameras. An isotropic spatial resolution of ~1 μm is achieved thanks to the short source coherence length and the use of high numerical aperture microscope objectives. A detection sensitivity of ~90 dB is obtained by means of image averaging and pixel binning. In ophthalmology, reconstructed xz images from rat ocular tissue are presented, where cellular-level structures in the retina are revealed, demonstrating the unprecedented resolution of our instrument. Three-dimensional reconstructions of the mouse embryo allowing the study of the establishment of the anterior-posterior axis are shown. Finally we present the first results of embryonic imaging using the new rapid acquisition full-field OCT system, which offers an acquisition time of 10 μs per frame.

  20. In Vivo Application of Optogenetics for Neural Circuit Analysis

    PubMed Central

    2012-01-01

    Optogenetics combines optical and genetic methods to rapidly and reversibly control neural activities or other cellular functions. Using genetic methods, specific cells or anatomical pathways can be sensitized to light through exogenous expression of microbial light activated opsin proteins. Using optical methods, opsin expressing cells can be rapidly and reversibly controlled by pulses of light of specific wavelength. With the high spatial temporal precision, optogenetic tools have enabled new ways to probe the causal role of specific cells in neural computation and behavior. Here, we overview the current state of the technology, and provide a brief introduction to the practical considerations in applying optogenetics in vivo to analyze neural circuit functions. PMID:22896801

  1. Molybdenum chloride incorporated sol-gel materials for oxygen sensing above room temperature

    NASA Astrophysics Data System (ADS)

    Osborn, D. J., III

    Maximizing the efficiency of the combustion process requires the ability to sense oxygen levels over a broad range of concentrations with fast response times under rapidly varying conditions of pressure and temperature to maintain the correct fuel/oxygen ratio in real-time. Quenching of the luminescence from organometallic compounds by oxygen has been used to develop a number of fiber-based sensors. A major drawback of these organometallic indicators for combustion applications is that the chromophores degrade with time, have a limited operational temperature range, typically room temperature +/-25C, and lack long-term reliability. This work investigates luminescent molybdenum clusters based on Mo6Cl12 were as replacements for organometallic indicators. A study of the high temperature stability of Mo6Cl 12 in air revealed irreversible changes in the optical absorption spectrum at T >250C and a loss of the red luminescence characteristic of the pristine clusters. Thermal aging experiments run in air and under nitrogen point to oxidation of the clusters as the cause of the change in optical properties. X-ray powder diffraction measurements on samples annealed at 300C under controlled conditions are consistent with oxidation of Mo6Cl 12 to form MoO3. Optical and thermal aging experiments show that K2Mo6Cl141H2O, the alkali metal salt of Mo6Cl12, has higher thermal stability and remains luminescent after long-term aging in air at 280C. Methods were developed for depositing K2Mo6Cl141H 2O-incorporated sol--gel films on planar and optical fiber substrates by dip coating and spray coating. The mechanical properties of the films depended on the film thickness; thin films were stable, but cracks often formed in the thicker films needed for sensors. This problem was addressed using two strategies: altering the components of the sol--gel solutions used to embed the clusters and by devising a composite approach to sensing layers where a slurry of fully cured sol--gel particles containing K2Mo 6Cl141H2O in a sol--gel "binder" were deposited on substrates. The optical properties of a large number of fiber sensors were tested up to 102C, with the best results obtained using the K2Mo6Cl141H2O/sol--gel composite sensing film. Fiber M demonstrated quenching of 4--6x between <0.001% and 21.1% (v/v) oxygen at 23, 42, 60, 81 and 102C respectively. The sensor switches abruptly between two well defined levels with a response time of less than 10 s. Quenching of the cluster luminescence by oxygen obeys a two-site Stern-Volmer relationship based on measurements of fiber 121 at 42, 73, and 102C, with sensitivity decreasing as temperature increases. The cycle-cycle variations for six cycles between nitrogen and oxygen at 58C for fiber 45 corresponds to an uncertainty of +/-1% to +/-15% in oxygen concentration over the entire measurement range from 21.1% (v/v) to 2.1% (v/v) oxygen respectively. The long-term performance data from cycling fiber 70 between <0.001% (v/v) and 21.1% (v/v) oxygen for 14 hours was stable over the entire period and variations in sensor signal were found to be synchronous with the temperature fluctuations in the flow through cell. The magnitude of the sensor signal up to 102C is ~3-nW for ~300 microW of incident excitation power. For the current 15-cm long fiber sensor, the autofluorescence (0.011 nW) is 40x smaller than the signal (~ 0.4 nW) in 20% (v/v) oxygen.

  2. Clinical applications of in vivo neutron-activation analysis

    SciTech Connect

    Cohn, S.H.

    1982-01-01

    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.

  3. In-vivo neutron activation analysis: principles and clinical applications

    SciTech Connect

    Cohn, S.H.

    1982-01-01

    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. It seems likely that by the end of this century there will have been significant progress with this research tool, and exciting insights obtained into the nature and dynamics of human body composition.

  4. Endothelialized biomaterials for tissue engineering applications in vivo

    PubMed Central

    Khan, Omar F.; Sefton, Michael V.

    2011-01-01

    Rebuilding tissues involves the creation of a vasculature to supply nutrients and this in turn means that the endothelial cells (EC) of the resulting endothelium must be a quiescent, non- thrombogenic blood contacting surface. Such EC are deployed on biomaterials that are composed of natural materials such as extracellular matrix proteins or of synthetic polymers in the form of vascular grafts or tissue-engineered constructs. Because EC function is influenced by their origin, biomaterial surface chemistry and hemodynamics, these issues must be considered to optimize implant performance. This article reviews the recent in vivo use of endothelialized biomaterials and discusses the fundamental issues that must be considered when engineering functional vasculature. PMID:21549438

  5. High-speed multispectral fluorescence lifetime imaging implementation for in vivo applications

    PubMed Central

    Shrestha, Sebina; Applegate, Brian E.; Park, Jesung; Xiao, Xudong; Pande, Paritosh; Jo, Javier A.

    2016-01-01

    Fluorescence lifetime imaging microscopy (FLIM) offers a noninvasive approach for characterizing the biochemical composition of biological tissue. In recent years, there has been an increasing interest in the application of multispectral FLIM for medical diagnosis. Central to the clinical translation of FLIM technology is the development of robust, fast, and cost-effective FLIM instrumentation suitable for in vivo tissue imaging. Unfortunately, the predominant multispectral FLIM approaches suffer from limitations that impede the development of high-speed instruments for in vivo applications. We present a cost-effective scanning multispectral FLIM implementation capable of achieving pixel rates on the order of tens of kilohertz, which will facilitate the evaluation of FLIM for in vivo applications. PMID:20680057

  6. Stimuli-responsive photoacoustic nanoswitch for in vivo sensing applications.

    PubMed

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

    2014-08-26

    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

  7. Histotripsy for Pediatric Cardiac Applications: In Vivo Neonatal Pig Model

    NASA Astrophysics Data System (ADS)

    Miller, Ryan M.; Owens, Gabe; Ensing, Gregory; Ludomirsky, Achiau; Cain, Charles; Xu, Zhen

    2010-03-01

    This study investigated the in vivo feasibility of using histotripsy to non-invasively create a flow channel between the ventricles by generating a perforation of the ventricular septum, clinically referred to as a ventricular septum defect (VSD). The overall goal is to develop a non-invasive procedure to aid in the treatment of neonatal patients with complex congenital heart diseases such as Hypoplastic Left Heart Syndrome (HLHS). Histotripsy is a therapeutic ultrasound technique that produces mechanical fractionation of soft tissue through controlled cavitation. The study was conducted in a live and intact neonatal pig model. The ventricular septum in the neonatal pig heart was treated with histotripsy delivered by a spherically focused 1 MHz transducer positioned outside the chest wall. Histotripsy treatment was applied using 5-cycle ultrasound pulses at 1 kHz pulse repetition frequency with 12-18 MPa peak negative pressure. The treatment was guided and monitored with ultrasound imaging. In all nine subjects treated, a bubble cloud was generated on the ventricular septum using histotripsy, and visualized with ultrasound imaging. Within 20 seconds to 4 minutes following the initiation of a bubble cloud, a VSD was created in all nine pigs and confirmed by the detection of blood flow through the ventricular septum with color Doppler ultrasound. Gross morphology and histology on all hearts showed a demarcated perforation in the ventricular septum. This study shows that a VSD can be created in an intact neonatal animal using extracorporeal histotripsy under real-time ultrasound guidance.

  8. Optogenetic tools for in vivo applications in neonatal mice

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

    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.

  9. Deep tissue fluorescence imaging and in vivo biological applications

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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.

  10. A telemedicine application to schedule temperature in an in vivo sensor network for cancer treatment.

    PubMed

    Kamal, Rossi; Hong, Choong Seon; Lee, Seok-Geun

    2012-12-01

    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

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

    PubMed Central

    Kamal, Rossi; Lee, Seok-Geun

    2012-01-01

    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

  12. Carbon nanotubes from synthesis to in vivo biomedical applications.

    PubMed

    Sajid, Muhammad Imran; Jamshaid, Usama; Jamshaid, Talha; Zafar, Nadiah; Fessi, H; Elaissari, Abdelhamid

    2016-03-30

    Owing to their unique and interesting properties, extensive research round the globe has been carried out on carbon nanotubes and carbon nanotubes based systems to investigate their practical usefulness in biomedical applications. The results from these studies demonstrate a great promise in their use in targeted drug delivery systems, diagnostic techniques and in bio-analytical applications. Although, carbon nanotubes possess quite interesting properties, which make them potential candidates in the biomedical science, but they also have some inherent properties which arise great concern regarding their biosafety. In this comprehensive review, we have discussed different aspects of carbon nanotubes and carbon nanotube based systems related to biomedical applications. In the beginning, a short historical account of these tiny yet powerful particles is given followed by discussion regarding their types, properties, methods of synthesis, large scale production method, purification techniques and characterization aspects of carbon nanotubes. In the second part of the review, the functionalization of carbon nanotubes is reviewed in detail, which is not only important to make them biocompatible and stable in biological systems but also render them a great property of loading various biomolecules, diagnostic and therapeutic moieties resulting in diversified applications. In the final part of the review, emphasis is given on the pharmacokinetic aspects of carbon nanotubes including administration routes, absorption mechanisms, distribution and elimination of carbon nanotubes based systems. Lastly, a comprehensive account about the potential biomedical applications has been given followed by insights into the future. PMID:26827920

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    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.

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

    SciTech Connect

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

    2014-07-31

    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. (laser biophotonics)

  15. 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)

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

    2014-07-01

    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.

  16. Tracking of stem cells in vivo for cardiovascular applications

    PubMed Central

    2014-01-01

    In the past ten years, the concept of injecting stem and progenitor cells to assist with rebuilding damaged blood vessels and myocardial tissue after injury in the heart and peripheral vasculature has moved from bench to bedside. Non-invasive imaging can not only provide a means to assess cardiac repair and, thereby, cellular therapy efficacy but also a means to confirm cell delivery and engraftment after administration. In this first of a two-part review, we will review the different types of cellular labeling techniques and the application of these techniques in cardiovascular magnetic resonance and ultrasound. In addition, we provide a synopsis of the cardiac cellular clinical trials that have been performed to-date. PMID:24406054

  17. In vivo confocal microscopy in dermatology: from research to clinical application

    NASA Astrophysics Data System (ADS)

    Ulrich, Martina; Lange-Asschenfeldt, Susanne

    2013-06-01

    Confocal laser scanning microscopy (CLSM) represents an emerging technique for the noninvasive histomorphological analysis of skin in vivo and has shown its applicability for dermatological research as well as its value as an adjunct tool in the clinical management of skin cancer patients. Herein, we aim to give an overview on the current clinical indications for CLSM in dermatology and also highlight the diverse applications of CLSM in dermatological research.

  18. 21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... cell culture processing applications. 876.5885 Section 876.5885 Food and Drugs FOOD AND DRUG... DEVICES Therapeutic Devices § 876.5885 Tissue culture media for human ex vivo tissue and cell culture processing applications. (a) Identification. Tissue culture media for human ex vivo tissue and cell...

  19. 21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... cell culture processing applications. 876.5885 Section 876.5885 Food and Drugs FOOD AND DRUG... DEVICES Therapeutic Devices § 876.5885 Tissue culture media for human ex vivo tissue and cell culture processing applications. (a) Identification. Tissue culture media for human ex vivo tissue and cell...

  20. 21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... cell culture processing applications. 876.5885 Section 876.5885 Food and Drugs FOOD AND DRUG... DEVICES Therapeutic Devices § 876.5885 Tissue culture media for human ex vivo tissue and cell culture processing applications. (a) Identification. Tissue culture media for human ex vivo tissue and cell...

  1. In Vivo Application and Localization of Transcranial Focused Ultrasound Using Dual-Mode Ultrasound Arrays

    PubMed Central

    Haritonova, Alyona; Liu, Dalong; Ebbini, Emad S.

    2015-01-01

    Focused ultrasound (FUS) has been proposed for a variety of transcranial applications, including neuromodulation, tumor ablation, and blood brain barrier opening. A flurry of activity in recent years has generated encouraging results demonstrating its feasibility in these and other applications. To date, monitoring of FUS beams have been primarily accomplished using MR guidance, where both MR thermography and elastography have been used. The recent introduction of real-time dual-mode ultrasound array (DMUA) systems offers a new paradigm in transcranial focusing. In this paper, we present first experimental results of ultrasound-guided transcranial FUS (tFUS) application in a rodent brain, both ex vivo and in vivo. DMUA imaging is used for visualization of the treatment region for placement of the focal spot within the brain. This includes the detection and localization of pulsating blood vessels at or near the target point(s). In addition, DMUA imaging is used to monitor and localize the FUS-tissue interactions in real-time. In particular, a concave (40-mm radius of curvature), 32-element, 3.5 MHz DMUA prototype was used for imaging and tFUS application in ex vivo and in vivo rat model. The ex vivo experiments were used to evaluate the point spread function (psf) of the transcranial DMUA imaging at various points within the brain. In addition, DMUA-based transcranial ultrasound thermography measurements were compared with thermocouple measurements of subtherapeutic tFUS heating in rat brain ex vivo. The ex vivo setting was also used to demonstrate the DMUA capability to produce localized thermal lesions. The in vivo experiments were designed to demonstrate the ability of the DMUA to apply, monitor, and localize subtherapeutic tFUS patterns that could be beneficial in transient blood brain barrier opening. The results show that, while the DMUA focus is degraded due to the propagation through the skull, it still produces localized heating effects within sub-millimeter volume. In addition, DMUA transcranial echo data from brain tissue allow for reliable estimation of temperature change. PMID:26670845

  2. In Vivo application and localization of transcranial focused ultrasound using dual-mode ultrasound arrays.

    PubMed

    Haritonova, Alyona; Liu, Dalong; Ebbini, Emad S

    2015-12-01

    Focused ultrasound (FUS) has been proposed for a variety of transcranial applications, including neuromodulation, tumor ablation, and blood-brain barrier opening. A flurry of activity in recent years has generated encouraging results demonstrating its feasibility in these and other applications. To date, monitoring of FUS beams has been primarily accomplished using MR guidance, where both MR thermography and elastography have been used. The recent introduction of real-time dual-mode ultrasound array (DMUA) systems offers a new paradigm in transcranial focusing. In this paper, we present first experimental results of ultrasound-guided transcranial FUS (tFUS) application in a rodent brain, both ex vivo and in vivo. DMUA imaging is used for visualization of the treatment region for placement of the focal spot within the brain. This includes the detection and localization of pulsating blood vessels at or near the target point(s). In addition, DMUA imaging is used to monitor and localize the FUS-tissue interactions in real time. In particular, a concave (40 mm radius of curvature), 32-element, 3.5-MHz DMUA prototype was used for imaging and tFUS application in ex vivo and in vivo rat models. The ex vivo experiments were used to evaluate the point spread function of the transcranial DMUA imaging at various points within the brain. In addition, DMUA-based transcranial ultrasound thermography measurements were compared with thermocouple measurements of subtherapeutic tFUS heating in rat brain ex vivo. The ex vivo setting was also used to demonstrate the capability of DMUA to produce localized thermal lesions. The in vivo experiments were designed to demonstrate the ability of the DMUA to apply, monitor, and localize subtherapeutic tFUS patterns that could be beneficial in transient blood-brain barrier opening. The results show that although the DMUA focus is degraded due to the propagation through the skull, it still produces localized heating effects within a sub-millimeter volume. In addition, DMUA transcranial echo data from brain tissue allow for reliable estimation of temperature change. PMID:26670845

  3. Nanoparticle-based delivery system for application of siRNA in vivo.

    PubMed

    Wang, Yan; Li, Zhiguo; Han, Yee; Liang, Leo Hwa; Ji, Aimin

    2010-02-01

    Small interfering RNAs (siRNAs) silence the expression of specific target genes by mediating RNA interference (RNAi) in mammalian cells. siRNAs have not only been widely used as a valuable tool for functional genomics research, but they also have demonstrated great potential in biomedical therapeutic applications for diseases caused by abnormal gene overexpression or mutation. One of the most important issues to overcome before full clinical application is the development of effective administration methods for siRNAs to the target tissue or cells in vivo, which is highly dependent on the delivery system. Currently, there are two major kinds of in vivo delivery systems: viral or nonviral. As one of the nonviral carrier systems, nanoparticles, combinations of liposomes and cationic polymer complexes, have exhibited improved in vivo stability, target specificity, and cell/tissue uptake and internalization of the encapsulated RNAi oligos, which result in more effective silencing with less cellular toxicity and immune stimulation. This review will discuss the latest advancements in nanoparticle-mediated RNAi delivery systems, including nano-materials, preparation, and characteristics. In conjunction, the clinical trial cases related to the nanoparticle-siRNA complexes will be highlighted. The safety issues of nanoparticles used in vivo will also be mentioned. Finally, this review will summarize the perspectives for future applications of nanoparticle-mediated RNAi delivery systems. PMID:20359287

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

    PubMed Central

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

    2010-01-01

    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

  5. Application of in vivo measurements for the management of cyanobacteria breakthrough into drinking water treatment plants.

    PubMed

    Zamyadi, Arash; Dorner, Sarah; Ndong, Mouhamed; Ellis, Donald; Bolduc, Anouka; Bastien, Christian; Prvost, Michle

    2014-02-01

    The increasing presence of potentially toxic cyanobacterial blooms in drinking water sources and within drinking water treatment plants (DWTPs) has been reported worldwide. The objectives of this study are to validate the application of in vivo probes for the detection and management of cyanobacteria breakthrough inside DWTPs, and to verify the possibility of treatment adjustment based on intensive real-time monitoring. In vivo phycocyanin YSI probes were used to monitor the fate of cyanobacteria in raw water, clarified water, filtered water, and chlorinated water in a full scale DWTP. Simultaneous samples were also taken for microscopic enumeration. The in vivo probe was successfully used to detect the incoming densities of high cyanobacterial cell number into the clarification process and their breakthrough into the filtered water. In vivo probes were used to trace the increase in floating cells over the clarifier, a robust sign of malfunction of the coagulation-sedimentation process. Pre-emptive treatment adjustments, based on in vivo probe monitoring, resulted in successful removal of cyanobacterial cells. The field results on validation of the probes with cyanobacterial bloom samples showed that the probe responses are highly linear and can be used to trigger alerts to take action. PMID:24429778

  6. Applications of the direct photon absorption technique for measuring bone mineral content in vivo. Determination of body composition in vivo

    NASA Technical Reports Server (NTRS)

    Cameron, J. R.

    1972-01-01

    The bone mineral content, BMC, determined by monoenergetic photon absorption technique, of 29 different locations on the long bones and vertebral columns of 24 skeletons was measured. Compressive tests were made on bone from these locations in which the maximum load and maximum stress were measured. Also the ultimate strain, modulus of elasticity and energy absorbed to failure were determined for compact bone from the femoral diaphysis and cancellous bone from the eighth through eleventh thoracic vertebrae. Correlations and predictive relationships between these parameters were examined to investigate the applicability of using the BMC at sites normally measured in vivo, i.e. radius and ulna in estimating the BMC and/or strength of the spine or femoral neck. It was found that the BMC at sites on the same bone were highly correlated r = 0.95 or better; the BMC at sites on different bones were also highly interrelated, r = 0.85. The BMC at various sites on the long bones could be estimated to between 10 and 15 per cent from the BMC of sites on the radius or ulna.

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

    PubMed

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

    2010-10-01

    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

  8. Time-Resolved Microdialysis for In Vivo Neurochemical Measurements and Other Applications

    NASA Astrophysics Data System (ADS)

    Schultz, Kristin N.; Kennedy, Robert T.

    2008-07-01

    Monitoring changes in chemical concentrations over time in complex environments is typically performed using sensors and spectroscopic techniques. Another approach is to couple sampling methods, such as microdialysis, with chromatographic, electrophoretic, or enzymatic assays. Recent advances of such coupling have enabled improvements in temporal resolution, multianalyte capability, and automation. In a sampling and analysis method, the temporal resolution is set by the mass sensitivity of the analytical method, analysis time, and zone dispersion during sampling. Coupling methods with high speed and mass sensitivity to microdialysis sampling help to reduce some of these contributions to yield methods with temporal resolution of seconds. These advances have been primarily used in monitoring neurotransmitters in vivo. This review covers the problems associated with chemical monitoring in the brain, recent advances in using microdialysis for time-resolved in vivo measurements, sample applications, and other potential applications of the technology such as determining reaction kinetics and process monitoring.

  9. Hepatic ablation with multiple interstitial ultrasound applicators: initial ex vivo and computational studies

    NASA Astrophysics Data System (ADS)

    Prakash, Punit; Salgaonkar, Vasant A.; Burdette, E. Clif; Diederich, Chris J.

    2011-03-01

    Radiofrequency (RF) ablation has emerged as an effective method for treating liver tumors under 3 cm in diameter. Multiple applicator devices and techniques - using RF, microwave and other modalities - are under development for thermal ablation of large and irregularly-shaped liver tumors. Interstitial ultrasound (IUS) applicators, comprised of linear arrays of independently powered tubular transducers, enable 3D control of the spatial power deposition profile and simultaneous ablation with multiple applicators. We evaluated IUS applicator configurations (parallel, converging and diverging implants) suitable for percutaneous and laparascopic placement with experiments in ex vivo bovine tissue and computational models. Ex vivo ablation zones measured 4.6+/-0.5 x 4.2+/-0.5 3.3+/-0.5 cm3 and 5.6+/-0.5 4.9+/-0.5 x 2.8+/-0.3 cm3 using three parallel applicators spaced 2 and 3 cm apart, respectively, and 4.0+/-0.3 3.2+/-0.4 2.9+/-0.2 cm3 using two parallel applicators spaced 2 cm apart. Computational models indicate in vivo ablation zones up to 4.5 4.4 5.5 cm3 and 5.7 4.8 5.2 cm3, using three applicators spaced 2 and 3 cm apart, respectively. Converging and diverging implant patterns can also be employed for conformal ablation of irregularly-shaped tumor margins by tailoring power levels along each device. Simultaneously powered interstitial ultrasound devices can create tailored ablation zones comparable to currently available RF devices and similarly sized microwave antennas.

  10. Optical brain imaging in vivo: techniques and applications from animal to man

    PubMed Central

    Hillman, Elizabeth M. C.

    2008-01-01

    Optical brain imaging has seen 30 years of intense development, and has grown into a rich and diverse field. In-vivo imaging using light provides unprecedented sensitivity to functional changes through intrinsic contrast, and is rapidly exploiting the growing availability of exogenous optical contrast agents. Light can be used to image microscopic structure and function in vivo in exposed animal brain, while also allowing noninvasive imaging of hemodynamics and metabolism in a clinical setting. This work presents an overview of the wide range of approaches currently being applied to in-vivo optical brain imaging, from animal to man. Techniques include multispectral optical imaging, voltage sensitive dye imaging and speckle-flow imaging of exposed cortex, in-vivo two-photon microscopy of the living brain, and the broad range of noninvasive topography and tomography approaches to near-infrared imaging of the human brain. The basic principles of each technique are described, followed by examples of current applications to cutting-edge neuroscience research. In summary, it is shown that optical brain imaging continues to grow and evolve, embracing new technologies and advancing to address ever more complex and important neuroscience questions. PMID:17994863

  11. Techniques and applications of in vivo diffusion imaging of articular cartilage.

    PubMed

    Raya, Jos G

    2015-06-01

    Early in the process of osteoarthritis (OA) the composition (water, proteoglycan [PG], and collagen) and structure of articular cartilage is altered leading to changes in its mechanical properties. A technique that can assess the composition and structure of the cartilage in vivo can provide insight in the mechanical integrity of articular cartilage and become a powerful tool for the early diagnosis of OA. Diffusion tensor imaging (DTI) has been proposed as a biomarker for cartilage composition and structure. DTI is sensitive to the PG content through the mean diffusivity and to the collagen architecture through the fractional anisotropy. However, the acquisition of DTI of articular cartilage in vivo is challenging due to the short T2 of articular cartilage (?40 ms at 3 Tesla) and the high resolution needed (0.5-0.7 mm in plane) to depict the cartilage anatomy. We describe the pulse sequences used for in vivo DTI of articular cartilage and discus general strategies for protocol optimization. We provide a comprehensive review of measurements of DTI of articular cartilage from ex vivo validation experiments to its recent clinical applications. PMID:25865215

  12. Quantitative in vivo receptor binding. I. Theory and application to the muscarinic cholinergic receptor

    SciTech Connect

    Frey, K.A.; Ehrenkaufer, R.L.; Beaucage, S.; Agranoff, B.W.

    1985-02-01

    A novel approach to in vivo receptor binding experiments is presented which allows direct quantitation of binding site densities. The method is based on an equilibrium model of tracer uptake and is designed to produce a static distribution proportional to receptor density and to minimize possible confounding influences of regional blood flow, blood-brain barrier permeability, and nonspecific binding. This technique was applied to the measurement of regional muscarinic cholinergic receptor densities in rat brain using (/sup 3/H)scopolamine. Specific in vivo binding of scopolamine demonstrated saturability, a pharmacologic profile, and regional densities which are consistent with interaction of the tracer with the muscarinic receptor. Estimates of receptor density obtained with the in vivo method and in vitro measurements in homogenates were highly correlated. Furthermore, reduction in striatal muscarinic receptors following ibotenic acid lesions resulted in a significant decrease in tracer uptake in vivo, indicating that the correlation between scopolamine distribution and receptor density may be used to demonstrate pathologic conditions. We propose that the general method presented here is directly applicable to investigation of high affinity binding sites for a variety of radioligands.

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    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.

  14. Fast 3-D photoacoustic imaging in vivo with a high frequency ultrasound array toward clinical applications

    NASA Astrophysics Data System (ADS)

    Song, Liang; Maslov, Konstantin; Bitton, Rachel; Shung, K. Kirk; Wang, Lihong V.

    2009-02-01

    We present an in vivo reflection-mode photoacoustic microscopy system that performs B-scan imaging at 50 Hz with realtime beamforming and 3-D imaging of 166 B-scan frames at 1 Hz with post-beamforming. To our knowledge, this speed is currently the fastest in high frequency photoacoustic imaging. In addition, with a custom fiber based light delivery system, the imaging device is capable of performing handheld operation. Software for image processing and display with clinically user-friendly graphic user interface (GUI) is developed. The system has axial, lateral, and elevational resolutions of 25, 70, and 200 ?m, respectively, and can image 3 mm deep in scattering biological tissue. Volumetric images of subcutaneous vasculature in murine are demonstrated in vivo. The system is anticipated to have potential clinical applications in skin melanoma detection due to its unique ability to image in realtime and to image anatomical sites inaccessible to other imaging systems.

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

    PubMed

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

    2014-06-10

    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

  16. In vivo evaluation of drug delivery after ultrasound application: A new use for the photoacoustic technique

    NASA Astrophysics Data System (ADS)

    Barja, P. R.; Acosta-Avalos, D.; Rompe, P. C. B.; Dos Anjos, F. H.; Marciano, F. R.; da Silva, M. D.

    2005-06-01

    Ultrasound application is a therapeutical resource widely employed in physiotherapy. One of its applications is the phonophoresis, a technique in which the ultrasound radiation is utilized to deliver drugs through the skin to soft tissues. The proposal of our study was to employ the Photoacoustic Technique to evaluate the efficacy of such treatment, analyzing if phonophoresis could enhance drug delivery through skin when compared to the more traditional method of manual massage. The configuration of the system employed was such that it was possible to perform in vivo measurements, which is a pre-requisite for this kind of study. The changes observed in the photoacoustic signal amplitude after each form of drug application were attributed to changes in the thermal effusivity of the system, due to penetration of the drug. The technique was able to detect differences in drug delivery between the specified physiotherapy treatments, indicating that phonophoresis enhances drug absorption by tissue.

  17. Applications of In Vitro-In Vivo Correlations in Generic Drug Development: Case Studies.

    PubMed

    Kaur, Paramjeet; Jiang, Xiaojian; Duan, John; Stier, Ethan

    2015-07-01

    In vitro-in vivo correlation (IVIVC) is a predictive mathematical model describing the relationship between an in vitro property and a relevant in vivo response. The main objective of an IVIVC is to serve as a surrogate for human bioequivalence (BE) studies, which may reduce the number of BE studies performed during the initial approval process as well as with certain scale-up and postapproval changes. The US Food and Drug Administration (FDA) published a regulatory guidance related to development, evaluation, and applications of IVIVC for extended-release (ER) oral dosage forms in September 1997. Despite the publication of this guidance, the deficiencies related to IVIVC are still identified by the Division of Bioequivalence in the process of Abbreviated New Drug Application (ANDA) review. Thus, the main objective of this article is to present the most commonly occurring deficiencies associated with IVIVCs via selected case studies from the ANDAs for oral ER drug products only. We searched internal FDA databases from January 1996 to December 2014 to identify the ANDAs for proposed generic oral ER drug products containing IVIVC. Only 14 ANDA submissions had IVIVC data, and most were not acceptable. Only one ANDA submission included adequate information related to IVIVC data enabling the completion of BE review within first review cycle. It is hoped that awareness of the deficiencies presented in our article would help the generic drug applicants to submit complete and appropriate information related to IVIVC data, ultimately, resulting in a more timely approval of ANDAs. PMID:25896303

  18. Description and application of instrumented staples for measuring in vivo bone strain.

    PubMed

    Buttermann, G R; Janevic, J T; Lewis, J L; Lindquist, C M; Wood, K B; Schendel, M J

    1994-08-01

    In vivo bone strain measurements using strain gages cemented to bony surfaces with cyanoacrylate polymers are limited in duration due to debonding of the gages from bone. As an alternative to the bone bonded strain gages, a technique was developed in which strain gages were first bonded to miniature staples and then the staples embedded into bone. The instrumented staples may be calibrated so that staple strain is directly proportional to bone strain. The method was first validated by comparing the staple output with cemented surface strain gages. Comparison of instrumented staples to cemented strain gages revealed only a 3% deviation from linearity during longitudinal bending; the staples were insensitive to transverse loading. The instrumented staples were then applied to the in vitro canine lumbar spine to determine L2-3 facet loads. Load testing, repeatibility of facet calibration, and validity testing of the in vitro instrumented staples were found to be comparable to that of the previous cemented strain gage techniques. In vivo facet joint application of the instrumented staples for periods of greater than 5 weeks gave load measurements comparable to our previous short-term in vivo studies obtained with cemented strain gages. The advantages of the instrumented staples are a more secure bonding to the bone, and less traumatic surgery for fixation. PMID:8089163

  19. Applications of nuclear techniques for in vivo body composition studies at Brookhaven National Laboratory

    SciTech Connect

    Cohn, S.H.; Ellis, K.J.; Vartsky, D.; Vaswani, A.N.; Wielopolski, L.

    1981-01-01

    A series of technical developments and their clinical applications in various nuclear technologies at Brookhaven National Laboratory is described. These include the development of a portable neutron activation facility for measuring cadmium in vivo in kidney and liver, a technique for the measurement of body iron utilizing nuclear resonant scattering of gamma rays, a non-invasive measure of the skeletal levels of lead by an x-ray fluorescence technique, and the development of a pulsed Van de Graaff generator as a source of pulsed neutrons for the measurement of lung silicon. (ACR)

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

    PubMed

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

    2014-11-15

    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) M(-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

  1. Qualichem In Vivo: A Tool for Assessing the Quality of In Vivo Studies and Its Application for Bisphenol A

    PubMed Central

    Maxim, Laura; van der Sluijs, Jeroen P.

    2014-01-01

    In regulatory toxicology, quality assessment of in vivo studies is a critical step for assessing chemical risks. It is crucial for preserving public health studies that are considered suitable for regulating chemicals are robust. Current procedures for conducting quality assessments in safety agencies are not structured, clear or consistent. This leaves room for criticism about lack of transparency, subjective influence and the potential for insufficient protection provided by resulting safety standards. We propose a tool called Qualichem in vivo that is designed to systematically and transparently assess the quality of in vivo studies used in chemical health risk assessment. We demonstrate its use here with 12 experts, using two controversial studies on Bisphenol A (BPA) that played an important role in BPA regulation in Europe. The results obtained with Qualichem contradict the quality assessments conducted by expert committees in safety agencies for both of these studies. Furthermore, they show that reliance on standardized guidelines to ensure scientific quality is only partially justified. Qualichem allows experts with different disciplinary backgrounds and professional experiences to express their individual and sometimes divergent viewsan improvement over the current way of dealing with minority opinions. It provides a transparent framework for expressing an aggregated, multi-expert level of confidence in a study, and allows a simple graphical representation of how well the study integrates the best available scientific knowledge. Qualichem can be used to compare assessments of the same study by different health agencies, increasing transparency and trust in the work of expert committees. In addition, it may be used in systematic evaluation of in vivo studies submitted by industry in the dossiers that are required for compliance with the REACH Regulation. Qualichem provides a balanced, common framework for assessing the quality of studies that may or may not be following standardized guidelines. PMID:24489958

  2. Near-infrared fluorescence labeling of iron nanoparticles and applications for cell labeling and in vivo imaging.

    PubMed

    Wang, Jinke; Liu, Yingxun; Hou, Yong; Chen, Zhongpin; Gu, Ning

    2012-01-01

    In recent years, the near-infrared fluorescence (NIRF) labeled iron nanoparticles were synthesized and applied to labeling human cells for monitoring the engraftment process, imaging tumors, testing intracellular molecular environment surrounding the nanoparticles, and tracing biodistribution of nanoparticles in vivo. These studies demonstrated that the NIRF-labeled iron nanoparticles provided an excellent method not only for cell labeling but also for in vivo monitoring and tracing of iron nanoparticles due to the excellent in vivo imaging performance of the NIR fluorophores. However, the availability of commercial iron nanoparticles labeled with suitable NIRF dyes is limited. Optimal wavelength for in vivo imaging is centered at 800 nm, where tissue autofluorescence is minimal. Here we describe the manufacture of 12-nm 3-dimercaptosuccinic acid-coated Fe(3)O(4) magnetic nanoparticles, their labeling with a new near-infrared fluorophore, IRDye800CW (excitation/emission: 778/806 nm), and their applications for cell labeling and in vivo imaging. PMID:22791436

  3. Live cell in vitro and in vivo imaging applications: accelerating drug discovery.

    PubMed

    Isherwood, Beverley; Timpson, Paul; McGhee, Ewan J; Anderson, Kurt I; Canel, Marta; Serrels, Alan; Brunton, Valerie G; Carragher, Neil O

    2011-01-01

    Dynamic regulation of specific molecular processes and cellular phenotypes in live cell systems reveal unique insights into cell fate and drug pharmacology that are not gained from traditional fixed endpoint assays. Recent advances in microscopic imaging platform technology combined with the development of novel optical biosensors and sophisticated image analysis solutions have increased the scope of live cell imaging applications in drug discovery. We highlight recent literature examples where live cell imaging has uncovered novel insight into biological mechanism or drug mode-of-action. We survey distinct types of optical biosensors and associated analytical methods for monitoring molecular dynamics, in vitro and in vivo. We describe the recent expansion of live cell imaging into automated target validation and drug screening activities through the development of dedicated brightfield and fluorescence kinetic imaging platforms. We provide specific examples of how temporal profiling of phenotypic response signatures using such kinetic imaging platforms can increase the value of in vitro high-content screening. Finally, we offer a prospective view of how further application and development of live cell imaging technology and reagents can accelerate preclinical lead optimization cycles and enhance the in vitro to in vivo translation of drug candidates. PMID:24310493

  4. In vivo Raman spectroscopy of biochemical changes in human skin by cosmetic application

    NASA Astrophysics Data System (ADS)

    Tosato, Maira Gaspar; dos Santos, Edson Pereira; Alves, Rani de Souza; Raniero, Leandro; Menezes, Priscila Fernanda C.; Kruger, Odivnia; Praes, Carlos Eduardo O.; Martin, Airton Abraho

    2010-02-01

    The skin aging process is mainly accelerated by external agents such as sunlight, air humidity and surfactants action. Changes in protein structures and hydration during the aging process are responsible for skin morphological variations. In this work the human skin was investigated by in vivo Raman spectroscopy before and after the topical applications of a cosmetic on 17 healthy volunteers (age 60 to 75). In vivo Raman spectra of the skin were obtained with a Spectrometer SpectraPro- 2500i (Pi-Acton), CCD detector and a 785 nm laser excitation source, collected at the beginning of experiment without cream (T0), after 30 (T30) and 60 (T60) days using the product. The primary changes occurred in the following spectral regions: 935 cm-1 (?CC), 1060 cm-1 (lipids), 1174 to 1201 cm-1 (tryptofan, phenylalanine and tyrosine), 1302 cm-1 (phospholipids), 1520 to 1580 cm-1 (C=C) and 1650 cm-1 (amide I). These findings indicate that skin positive effects were enhanced by a continuous cream application.

  5. Live Cell in Vitro and in Vivo Imaging Applications: Accelerating Drug Discovery

    PubMed Central

    Isherwood, Beverley; Timpson, Paul; McGhee, Ewan J; Anderson, Kurt I; Canel, Marta; Serrels, Alan; Brunton, Valerie G; Carragher, Neil O

    2011-01-01

    Dynamic regulation of specific molecular processes and cellular phenotypes in live cell systems reveal unique insights into cell fate and drug pharmacology that are not gained from traditional fixed endpoint assays. Recent advances in microscopic imaging platform technology combined with the development of novel optical biosensors and sophisticated image analysis solutions have increased the scope of live cell imaging applications in drug discovery. We highlight recent literature examples where live cell imaging has uncovered novel insight into biological mechanism or drug mode-of-action. We survey distinct types of optical biosensors and associated analytical methods for monitoring molecular dynamics, in vitro and in vivo. We describe the recent expansion of live cell imaging into automated target validation and drug screening activities through the development of dedicated brightfield and fluorescence kinetic imaging platforms. We provide specific examples of how temporal profiling of phenotypic response signatures using such kinetic imaging platforms can increase the value of in vitro high-content screening. Finally, we offer a prospective view of how further application and development of live cell imaging technology and reagents can accelerate preclinical lead optimization cycles and enhance the in vitro to in vivo translation of drug candidates. PMID:24310493

  6. In vivo 783-channel diffuse reflectance imaging system and its application

    NASA Astrophysics Data System (ADS)

    Yang, Joon-Mo; Han, Yong-Hui; Yoon, Gilwon; Ahn, Byung Soo; Lee, Byung-Cheon; Soh, Kwang-Sup

    2007-08-01

    A fiber-based reflectance imaging system was constructed to produce in vivo absorption spectroscopic images of biological tissues with diffuse light in the cw domain. The principal part of this system is the 783-channel fiber probe, composed of 253 illumination fibers and 530 detection fibers distributed in a 2020 mm square region. During illumination with the 253 illumination fibers, diffuse reflected lights are collected by the 530 detection fibers and recorded simultaneously as an image with an electron multiplying CCD camera for fast data acquisition. After signal acquisition, a diffuse reflectance image was reconstructed by applying the spectral normalization method we devised. To test the applicability of the spectral normalization, we conducted two phantom experiments with chicken breast tissue and white Delrin resin by using animal blood as an optical inhomogeneity. In the Delrin phantom experiment, we present images produced by two methods, spectral normalization and reference signal normalization, along with a comparison of the two. To show the feasibility of our system for biomedical applications, we took images of a human vein in vivo with the spectral normalization method.

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

    PubMed Central

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

    2008-01-01

    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

  8. An electro-responsive hydrogel for intravascular applications: an in vitro and in vivo evaluation.

    PubMed

    Verbrugghe, Peter; Verhoeven, Jelle; Coudyzer, Walter; Verbeken, Eric; Dubruel, Peter; Mendes, Eduardo; Stam, Frank; Meuris, Bart; Herijgers, Paul

    2015-11-01

    There is a growing interest in using hydrogels for biomedical applications, because of more favourable characteristics. Some of these hydrogels can be activated by using particular stimuli, for example electrical fields. These stimuli can change the hydrogel shape in a predefined way. It could make them capable of adaptation to patient-specific anatomy even post-implantation. This is the first paper aiming to describe in vivo studies of an electro-responsive, Pluronic F127 based hydrogel, for intravascular applications. Pluronic methacrylic acid hydrogel (PF127/MANa) was in vitro tested for its haemolytic and cytotoxic effects. Minimal invasive implantation in the carotid artery of sheep was used to evaluate its medium-term biological effects, through biochemical, macroscopic, radiographic, and microscopic evaluation. Indirect and direct testing of the material gave no indication of the haemolytic effects of the material. Determination of fibroblast viability after 24 h of incubation in an extract of the hydrogel showed no cytotoxic effects. Occlusion was obtained within 1 h following in vivo implantation. Evaluation at time of autopsy showed a persistent occlusion with no systemic effects, no signs of embolization and mild effects on the arterial wall. An important proof-of-concept was obtained showing biocompatibility and effectiveness of a pluronic based electro-responsive hydrogel for obtaining an arterial occlusion with limited biological impact. So the selected pluronic-methacrylic acid based hydrogel can be used as an endovascular occlusion device. More importantly it is the first step in further development of electro-active hydrogels for a broad range of intra-vascular applications (e.g. system to prevent endoleakage in aortic aneurysm treatment, intra-vascular drug delivery). PMID:26474577

  9. Development and Applications of Laminar Optical Tomography for In Vivo Imaging

    NASA Astrophysics Data System (ADS)

    Burgess, Sean A.

    Laminar optical tomography (LOT) is an optical imaging technique capable of making depth-resolved measurements of absorption and fluorescence contrast in scattering tissue. LOT was first demonstrated in 2004 by Hillman et al [1]. The technique combines a non-contact laser scanning geometry, similar to a low magnification confocal microscope, with the imaging principles of diffuse optical tomography (DOT). This thesis describes the development and application of a second generation LOT system, which acquires both fluorescence and multi-wavelength measurements simultaneously and is better suited for in vivo measurements. Chapter 1 begins by reviewing the interactions of light with tissue that form the foundation of optical imaging. A range of related optical imaging techniques and the basic principles of LOT imaging are then described. In Chapter 2, the development of the new LOT imaging system is described including the implementation of a series of interfaces to allow clinical imaging. System performance is then evaluated on a range of imaging phantoms. Chapter 3 describes two in vivo imaging applications explored using the second generation LOT system, first in a clinical setting where skin lesions were imaged, and then in a laboratory setting where LOT imaging was performed on exposed rat cortex. The final chapter provides a brief summary and describes future directions for LOT. LOT has the potential to find applications in medical diagnostics, surgical guidance, and in-situ monitoring owing to its sensitivity to absorption and fluorescence contrast as well as its ability to provide depth sensitive measures. Optical techniques can characterize blood volume and oxygenation, two important biological parameters, through measurements at different wavelengths. Fluorescence measurements, either from autofluorescence or fluorescent dyes, have shown promise for identifying and analyzing lesions in various epithelial tissues including skin [2, 3], colon [4], esophagus [5, 6], oral mucosa [7, 8], and cervix [9]. The desire to capture these types of measurements with LOT motivated much of the work presented here.

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

    PubMed

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

    2014-10-27

    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 μm, 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. PMID:25422525

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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 μm, 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.

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

    SciTech Connect

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

    2014-10-27

    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 μm, 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.

  13. The application of quantum dots for the melanoma tumor in vivo imaging

    NASA Astrophysics Data System (ADS)

    Feng, Yayi; Zhai, Peng; Wang, Xiaomei; Ying, Ming; Wu, Jinbo; Zhu, Xiaomei; Lin, Guimiao; Chen, Qiang; Xu, Gaixia

    2014-09-01

    Objective: Over the past decade, fluorescent semiconductor nanocrystals, also known as quantum dots (QDs), have been applied in biomedical imaging in vitro and in vivo because of their fascinating optical properties. In this work, we investigated the application of CdTe QDs for tumor fluorescence in vivo imaging. Methods: The transparent dorsal skin fold window chamber (DSFC) was constructed on the 4~6 week-old BALB/c mice. The melanoma cells stably expressing green fluorescent protein ---ZsGreen were transplanted into the chamber and the melanoma DSFC model was established successfully. The water soluble CdTe QDs were synthesized and then administrated in the model through the tail intravenous injection. The fluorescent expression of B16 cells were assayed by fluorescent microscopy, the tumor growth, the blood capillaries distributions and its dynamic changes were observed by stereomicroscopy and laser scanning confocal microscopy. Results: The results demonstrated that the expression efficiency of ZsGreen was 41%, which met the experimental requirement. The tumors was visible inside the chamber after implantation of melanoma cells for 5~6 days, while no obvious changes in mice behaviors were found. After injection of the QDs, CdTe QDs accumulated at the invading edge of a range of solid tumor. We could also observe the tumor cells growth near the blood vessels, the angiogenesis occurred inside the tumor and the local blood capillaries increased. Conclusions: This work provided a new strategy for the tumor in vivo imaging and the development of targeted antineoplastic drugs.

  14. Quantitative analysis of bone and soft tissue by micro-computed tomography: applications to ex vivo and in vivo studies

    PubMed Central

    Campbell, Graeme M; Sophocleous, Antonia

    2014-01-01

    Micro-computed tomography (micro-CT) is a high-resolution imaging modality that is capable of analysing bone structure with a voxel size on the order of 10??m. With the development of in vivo micro-CT, where disease progression and treatment can be monitored in a living animal over a period of time, this modality has become a standard tool for preclinical assessment of bone architecture during disease progression and treatment. For meaningful comparison between micro-CT studies, it is essential that the same parameters for data acquisition and analysis methods be used. This protocol outlines the common procedures that are currently used for sample preparation, scanning, reconstruction and analysis in micro-CT studies. Scan and analysis methods for trabecular and cortical bone are covered for the femur, tibia, vertebra and the full neonate body of small rodents. The analysis procedures using the software provided by ScancoMedical and Bruker are discussed, and the routinely used bone architectural parameters are outlined. This protocol also provides a section dedicated to in vivo scanning and analysis, which covers the topics of anaesthesia, radiation dose and image registration. Because of the expanding research using micro-CT to study other skeletal sites, as well as soft tissues, we also provide a review of current techniques to examine the skull and mandible, adipose tissue, vasculature, tumour severity and cartilage. Lists of recommended further reading and literature references are included to provide the reader with more detail on the methods described. PMID:25184037

  15. Biomedical applications of polyhydroxyalkanoates: an overview of animal testing and in vivo responses.

    PubMed

    Valappil, Sabeel P; Misra, Superb K; Boccaccini, Aldo R; Roy, Ipsita

    2006-11-01

    Polyhydroxyalkanoates (PHAs) have been established as biodegradable polymers since the second half of the twentieth century. Altering monomer composition of PHAs allows the development of polymers with favorable mechanical properties, biocompatibility and desirable degradation rates, under specific physiological conditions. Hence, the medical applications of PHAs have been explored extensively in recent years. PHAs have been used to develop devices, including sutures, nerve repair devices, repair patches, slings, cardiovascular patches, orthopedic pins, adhesion barriers, stents, guided tissue repair/regeneration devices, articular cartilage repair devices, nerve guides, tendon repair devices, bone-marrow scaffolds, tissue engineered cardiovascular devices and wound dressings. So far, various tests on animal models have shown polymers, from the PHA family, to be compatible with a range of tissues. Often, pyrogenic contaminants copurified with PHAs limit their pharmacological application rather than the monomeric composition of the PHAs and thus the purity of the PHA material is critical. This review summarizes the animal testing, tissue response, in vivo molecular stability and challenges of using PHAs for medical applications. In future, PHAs may become the materials of choice for various medical applications. PMID:17280548

  16. An Alumina Toughened Zirconia Composite for Dental Implant Application: In Vivo Animal Results

    PubMed Central

    Schierano, Gianmario; Faga, Maria Giulia; Menicucci, Giulio; Sabione, Cristian; Genova, Tullio; von Degerfeld, Mitzy Mauthe; Peirone, Bruno; Cassenti, Adele; Cassoni, Paola; Carossa, Stefano

    2015-01-01

    Ceramic materials are widely used for biomedical applications because of their remarkable biological and mechanical properties. Composites made of alumina and zirconia are particularly interesting owing to their higher toughness with respect to the monolithic materials. On this basis, the present study is focused on the in vivo behavior of alumina toughened zirconia (ATZ) dental implants treated with a hydrothermal process. A minipig model was implemented to assess the bone healing through histology and mRNA expression at different time points (8, 14, 28, and 56 days). The novel ATZ implant was compared to a titanium clinical standard. The implants were analyzed in terms of microstructure and surface roughness before in vivo tests. The most interesting result deals with a statistically significant higher digital histology index for ATZ implants with respect to titanium standard at 56 days, which is an unprecedented finding, to the authors' knowledge. Even if further investigations are needed before proposing the clinical use in humans, the tested material proved to be a promising candidate among the possible ceramic dental implants. PMID:25945324

  17. Ex vivo evaluation of a microneedle array device for transdermal application.

    PubMed

    Indermun, Sunaina; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Modi, Girish; van Vuuren, Sandy; Luttge, Regina; Pillay, Viness

    2015-12-30

    A new approach of transdermal drug delivery is the use of microneedles. This promising technique offers the potential to be broadly used for drug administration as it enables the dramatic increase in permeation of medicaments across the stratum corneum. The potential of microneedles has evolved to spawn a plethora of potential transdermal applications. In order to advance the microneedle capabilities and possibly revolutionize advanced drug delivery, this study introduces a novel transdermal electro-modulated hydrogel-microneedle array (EMH-MNA) device composed of a nano-porous, embeddable ceramic microneedle array as well as an optimized EMH for the electro-responsive delivery of indomethacin through the skin. The ex vivo permeation as well as drug release experiments were performed on porcine skin tissue to ascertain the electro-responsive capabilities of the device. In addition, the microbial permeation ability of the microneedles across the viable epidermis in both microneedle-punctured skin as well as hypodermic needle-punctured skin was determined. Ex vivo evaluation of the EMH-MNA device across porcine skin demonstrated that without electro-stimulation, significantly less drug release was obtained (0.4540mg) as compared to electro-stimulation (2.93mg). PMID:26453791

  18. In vivo study of nanostructured akermanite/PEO coating on biodegradable magnesium alloy for biomedical applications.

    PubMed

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

    2015-05-01

    The major issue for biodegradable magnesium alloys is the fast degradation and release of hydrogen gas. In this article, we aim to overcome these disadvantages by using a surface modified magnesium implant. We have recently coated AZ91 magnesium implants by akermanite (Ca2 MgSi2 O7 ) through the combined electrophoretic deposition (EPD) and plasma electrolytic oxidation (PEO) methods. In this work, we performed the in vitro and in vivo examinations of these coated implants using L-929 cell line and rabbit animal model. The in vitro study confirmed the higher cytocompatibility of the coated implants compare to the uncoated ones. For the in vivo experiment, the rod samples were implanted into the greater trochanter of rabbits and monitored for two months. The results indicated a noticeable biocompatibility improvement of the coated implants which includes slower implant weight loss, reduction in Mg ion released from the coated samples in the blood plasma, lower release of hydrogen bubbles, increase in the amount of bone formation and ultimately lower bone inflammation after the surgery according to the histological images. Our data exemplifies that the proper surface treatment of the magnesium implants can improve their biocompatibility under physiological conditions to make them applicable in clinical uses. 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1798-1808, 2015. PMID:25203515

  19. An alumina toughened zirconia composite for dental implant application: in vivo animal results.

    PubMed

    Schierano, Gianmario; Mussano, Federico; Faga, Maria Giulia; Menicucci, Giulio; Manzella, Carlo; Sabione, Cristian; Genova, Tullio; von Degerfeld, Mitzy Mauthe; Peirone, Bruno; Cassenti, Adele; Cassoni, Paola; Carossa, Stefano

    2015-01-01

    Ceramic materials are widely used for biomedical applications because of their remarkable biological and mechanical properties. Composites made of alumina and zirconia are particularly interesting owing to their higher toughness with respect to the monolithic materials. On this basis, the present study is focused on the in vivo behavior of alumina toughened zirconia (ATZ) dental implants treated with a hydrothermal process. A minipig model was implemented to assess the bone healing through histology and mRNA expression at different time points (8, 14, 28, and 56 days). The novel ATZ implant was compared to a titanium clinical standard. The implants were analyzed in terms of microstructure and surface roughness before in vivo tests. The most interesting result deals with a statistically significant higher digital histology index for ATZ implants with respect to titanium standard at 56 days, which is an unprecedented finding, to the authors' knowledge. Even if further investigations are needed before proposing the clinical use in humans, the tested material proved to be a promising candidate among the possible ceramic dental implants. PMID:25945324

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

    PubMed Central

    Uusitalo, Larissa M.; Hempel, Nadine

    2012-01-01

    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

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

    PubMed Central

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

    2014-01-01

    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

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

    PubMed

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

    2014-01-01

    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

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

    SciTech Connect

    Palicz, Zoltn; Jenes, gnes; Gll, Tams; Miszti-Blasius, Kornl; Kollr, Sndor; Kovcs, Ilona; Emri, Mikls; Mrin, Terz; Leiter, va; Pcsi, Istvn; Cs?sz, va; Kall, Gerg?; Heged?s, Csaba; Virg, Lszl; Csernoch, Lszl; Szentesi, Pter

    2013-05-15

    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 ?gkg{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.

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

    PubMed

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

    2010-03-01

    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

  5. Click-assembled, oxygen-sensing nanoconjugates for depth-resolved, near-infrared imaging in a 3D cancer model.

    PubMed

    Nichols, Alexander J; Roussakis, Emmanuel; Klein, Oliver J; Evans, Conor L

    2014-04-01

    Hypoxia is an important contributing factor to the development of drug-resistant cancer, yet few nonperturbative tools exist for studying oxygenation in tissues. While progress has been made in the development of chemical probes for optical oxygen mapping, penetration of such molecules into poorly perfused or avascular tumor regions remains problematic. A click-assembled oxygen-sensing (CAOS) nanoconjugate is reported and its properties demonstrated in an in?vitro 3D spheroid cancer model. The synthesis relies on the sequential click-based ligation of poly(amidoamine)-like subunits for rapid assembly. Near-infrared confocal phosphorescence microscopy was used to demonstrate the ability of the CAOS nanoconjugates to penetrate hundreds of micrometers into spheroids within hours and to show their sensitivity to oxygen changes throughout the nodule. This proof-of-concept study demonstrates a modular approach that is readily extensible to a wide variety of oxygen and cellular sensors for depth-resolved imaging in tissue and tissue models. PMID:24590700

  6. A computational atlas of the hippocampal formation using ex vivo, ultra-high resolution MRI: Application to adaptive segmentation of in vivo MRI.

    PubMed

    Iglesias, Juan Eugenio; Augustinack, Jean C; Nguyen, Khoa; Player, Christopher M; Player, Allison; Wright, Michelle; Roy, Nicole; Frosch, Matthew P; McKee, Ann C; Wald, Lawrence L; Fischl, Bruce; Van Leemput, Koen

    2015-07-15

    Automated analysis of MRI data of the subregions of the hippocampus requires computational atlases built at a higher resolution than those that are typically used in current neuroimaging studies. Here we describe the construction of a statistical atlas of the hippocampal formation at the subregion level using ultra-high resolution, ex vivo MRI. Fifteen autopsy samples were scanned at 0.13 mm isotropic resolution (on average) using customized hardware. The images were manually segmented into 13 different hippocampal substructures using a protocol specifically designed for this study; precise delineations were made possible by the extraordinary resolution of the scans. In addition to the subregions, manual annotations for neighboring structures (e.g., amygdala, cortex) were obtained from a separate dataset of in vivo, T1-weighted MRI scans of the whole brain (1mm resolution). The manual labels from the in vivo and ex vivo data were combined into a single computational atlas of the hippocampal formation with a novel atlas building algorithm based on Bayesian inference. The resulting atlas can be used to automatically segment the hippocampal subregions in structural MRI images, using an algorithm that can analyze multimodal data and adapt to variations in MRI contrast due to differences in acquisition hardware or pulse sequences. The applicability of the atlas, which we are releasing as part of FreeSurfer (version 6.0), is demonstrated with experiments on three different publicly available datasets with different types of MRI contrast. The results show that the atlas and companion segmentation method: 1) can segment T1 and T2 images, as well as their combination, 2) replicate findings on mild cognitive impairment based on high-resolution T2 data, and 3) can discriminate between Alzheimer's disease subjects and elderly controls with 88% accuracy in standard resolution (1mm) T1 data, significantly outperforming the atlas in FreeSurfer version 5.3 (86% accuracy) and classification based on whole hippocampal volume (82% accuracy). PMID:25936807

  7. An electrochemically driven poly(dimethylsiloxane) microfluidic actuator: oxygen sensing and programmable flows and pH gradients.

    PubMed

    Mitrovski, Svetlana M; Nuzzo, Ralph G

    2005-06-01

    We describe the fabrication and performance of an integrated microelectrochemical reactor-a design possessing utility for multiple applications that include electrochemical sensing, the generation and manipulation of in-channel microfluidic pH gradients, and fluid actuation and flow. The device architecture is based on a three-electrode electrochemical cell design that incorporates a Pt interdigitated array (IDA) working (WE), a Pt counter (CE), and Ag pseudo-reference (RE) electrodes within a microfluidic network in which the WE is fully immersed in a liquid electrolyte confined in the channels. The microchannels are made from a conventional poly(dimethylsiloxane)(PDMS) elastomer, which serves also as a thin gas-permeable membrane through which gaseous reactants in the external ambient environment are supplied to the working electrode by diffusion. Due to the high permeability of oxygen through PDMS, the microfluidic cell supports significantly (>order of magnitude) higher current densities in the oxygen reduction reaction (ORR) than those measured in conventional (quiescent) electrochemical cells for the same electrode areas. We demonstrate in this work that, when operated at constant potential under mass transport control, the device can be utilized as a membrane-covered oxygen sensor, the response of which can be tuned by varying the thickness of the PDMS membrane. Depending on the experimental conditions under which the electrochemical ORR is performed, the data establish that the device can be operated as both a programmable pH gradient generator and a microfluidic pump. PMID:15915256

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

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

    PubMed

    Benayahu, Dafna; Socher, Rina; Shur, Irena

    2008-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

    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.

  12. 21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Tissue culture media for human ex vivo tissue and cell culture processing applications. 876.5885 Section 876.5885 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5885...

  13. 21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Tissue culture media for human ex vivo tissue and cell culture processing applications. 876.5885 Section 876.5885 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5885...

  14. In vivo bio-safety evaluations and diagnostic/therapeutic applications of chemically designed mesoporous silica nanoparticles.

    PubMed

    Chen, Yu; Chen, Hangrong; Shi, Jianlin

    2013-06-18

    The remarkable progress of nanotechnology and its application in biomedicine have greatly expanded the ranges and types of biomaterials from traditional organic material-based nanoparticles (NPs) to inorganic biomaterials or organic/inorganic hybrid nanocomposites due to the unprecedented advantages of the engineered inorganic material-based NPs. Colloidal mesoporous silica NPs (MSNs), one of the most representative and well-established inorganic materials, have been promoted into biology and medicine, and shifted from extensive in vitro research towards preliminary in vivo assays in small-animal disease models. In this comprehensive review, the recent progresses in chemical design and engineering of MSNs-based biomaterials for in vivo biomedical applications has been detailed and overviewed. Due to the intrinsic structural characteristics of elaborately designed MSNs such as large surface area, high pore volume and easy chemical functionalization, they have been extensively investigated for therapeutic, diagnostic and theranostic (concurrent diagnosis and therapy) purposes, especially in oncology. Systematic in vivo bio-safety evaluations of MSNs have revealed the evidences that the in vivo bio-behaviors of MSNs are strongly related to their preparation prodecures, particle sizes, geometries, surface chemistries, dosing parameters and even administration routes. In vivo pharmacokinetics and pharmacodynamics further demonstrated the effectiveness of MSNs as the passively and/or actively targeted drug delivery systems (DDSs) for cancer chemotherapy. Especially, the advance of nano-synthetic chemistry enables the production of composite MSNs for advanced in vivo therapeutic purposes such as gene delivery, stimuli-responsive drug release, photothermal therapy, photodynamic therapy, ultrasound therapy, or anti-bacteria in tissue engineering, or as the contrast agents for biological and diagnostic imaging. Additionally, the critical issues and potential challenges related to the chemical design/synthesis of MSNs-based "magic bullet" by advanced nano-synthetic chemistry and in vivo evaluation have been discussed to highlight the issues scientists face in promoting the translation of MSNs-based DDSs into clinical trials. PMID:23681931

  15. In vitro and in vivo characterization of novel biomaterial for transdermal application.

    PubMed

    Mundada, Atish S; Avari, Jasmine G

    2011-09-01

    Polymers have become an indispensable part in the design of a conventional as well as novel drug delivery system. Gum Copal (GC), a novel biomaterial obtained from Agathis species, is evaluated in the present study for its potential application as a matrix former in transdermal drug delivery systems. GC was initially characterized for various physicochemical properties and then mechanical characterization of the Plasticized films of GC was investigated. Verapamil hydrochloride (VH), owing to its pharmacokinetic properties, was selected as the model drug for the present work. Matrix type transdermal films of VH with GC, alone and in combination with polyvinyl pyrrolidone (PVP K-30), were developed and evaluated for various physicochemical properties. In-vitro drug release study was carried out using paddle over disk method and in-vitro skin permeation study was performed using human cadaver skin. On the basis of physicochemical properties, in-vitro drug release study and permeation performance, formulation F5 containing GC: PVP K-30 (60:40) was selected as an optimized formulation for in vivo study. Animal studies were carried out using Dawley rats and the data obtained from the plasma drug analysis showed that peak drug concentration of about 244.94 1.25 ng/mL was achieved in 6 h after the application of the patch and plasma drug concentration was maintained till 24 h. Skin irritancy test results proved the suitability of the biomaterial for transdermal application. The drug polymer interaction studies carried out using UV, FTIR and TLC analysis indicated that drug and polymer were compatible. Due to reasonably good mechanical properties, low water vapor transmission and sustained release capability, GC seems to be a promising film former for transdermal drug delivery. PMID:21696352

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

    NASA Astrophysics Data System (ADS)

    Sun, Conroy Ghin Chee

    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.

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

    PubMed Central

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

    2012-01-01

    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

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

    PubMed Central

    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

    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

  19. In vivo selection to identify bacterial strains with enhanced ecological performance in synbiotic applications.

    PubMed

    Krumbeck, Janina A; Maldonado-Gomez, Mara X; Martnez, Ins; Frese, Steven A; Burkey, Thomas E; Rasineni, Karuna; Ramer-Tait, Amanda E; Harris, Edward N; Hutkins, Robert W; Walter, Jens

    2015-04-01

    One strategy for enhancing the establishment of probiotic bacteria in the human intestinal tract is via the parallel administration of a prebiotic, which is referred to as a synbiotic. Here we present a novel method that allows a rational selection of putative probiotic strains to be used in synbiotic applications: in vivo selection (IVS). This method consists of isolating candidate probiotic strains from fecal samples following enrichment with the respective prebiotic. To test the potential of IVS, we isolated bifidobacteria from human subjects who consumed increasing doses of galactooligosaccharides (GOS) for 9 weeks. A retrospective analysis of the fecal microbiota of one subject revealed an 8-fold enrichment in Bifidobacterium adolescentis strain IVS-1 during GOS administration. The functionality of GOS to support the establishment of IVS-1 in the gastrointestinal tract was then evaluated in rats administered the bacterial strain alone, the prebiotic alone, or the synbiotic combination. Strain-specific quantitative real-time PCR showed that the addition of GOS increased B. adolescentis IVS-1 abundance in the distal intestine by nearly 2 logs compared to rats receiving only the probiotic. Illumina 16S rRNA sequencing not only confirmed the increased establishment of IVS-1 in the intestine but also revealed that the strain was able to outcompete the resident Bifidobacterium population when provided with GOS. In conclusion, this study demonstrated that IVS can be used to successfully formulate a synergistic synbiotic that can substantially enhance the establishment and competitiveness of a putative probiotic strain in the gastrointestinal tract. PMID:25616794

  20. In Vivo Selection To Identify Bacterial Strains with Enhanced Ecological Performance in Synbiotic Applications

    PubMed Central

    Krumbeck, Janina A.; Maldonado-Gomez, María X.; Martínez, Inés; Frese, Steven A.; Burkey, Thomas E.; Rasineni, Karuna; Ramer-Tait, Amanda E.; Harris, Edward N.; Hutkins, Robert W.

    2015-01-01

    One strategy for enhancing the establishment of probiotic bacteria in the human intestinal tract is via the parallel administration of a prebiotic, which is referred to as a synbiotic. Here we present a novel method that allows a rational selection of putative probiotic strains to be used in synbiotic applications: in vivo selection (IVS). This method consists of isolating candidate probiotic strains from fecal samples following enrichment with the respective prebiotic. To test the potential of IVS, we isolated bifidobacteria from human subjects who consumed increasing doses of galactooligosaccharides (GOS) for 9 weeks. A retrospective analysis of the fecal microbiota of one subject revealed an 8-fold enrichment in Bifidobacterium adolescentis strain IVS-1 during GOS administration. The functionality of GOS to support the establishment of IVS-1 in the gastrointestinal tract was then evaluated in rats administered the bacterial strain alone, the prebiotic alone, or the synbiotic combination. Strain-specific quantitative real-time PCR showed that the addition of GOS increased B. adolescentis IVS-1 abundance in the distal intestine by nearly 2 logs compared to rats receiving only the probiotic. Illumina 16S rRNA sequencing not only confirmed the increased establishment of IVS-1 in the intestine but also revealed that the strain was able to outcompete the resident Bifidobacterium population when provided with GOS. In conclusion, this study demonstrated that IVS can be used to successfully formulate a synergistic synbiotic that can substantially enhance the establishment and competitiveness of a putative probiotic strain in the gastrointestinal tract. PMID:25616794

  1. Osteogenic biphasic calcium sulphate dihydrate/iron-modified alpha-tricalcium phosphate bone cement for spinal applications: in vivo study.

    PubMed

    Vlad, M D; Sindilar, E V; Marioso, M L; Poeat?, I; Torres, R; Lpez, J; Barrac, M; Fernndez, E

    2010-02-01

    In this study, the biocompatibility and the osteogenic features of a new iron-modified alpha-tricalcium phosphate (IM/alpha-TCP) and calcium sulphate dihydrate (CSD) biphasic cement (IM/alpha-TCP/CSD-BC) have been investigated in terms of the in vivo cement resorption, bone tissue formation and host tissue response on sheep animal model. Histological evaluation performed on undecalcified cement-bone specimens assessed the in vivo behaviour. It has been shown that the new IM/alpha-TCP/CSD-BC has the ability to produce firm bone binding in vivo (i.e. bioactivity). Qualitative histology proved cement biocompatibility, osteoconduction and favourable resorption, mainly through a macrophage-mediated mechanism. The results showed that the new cements have biocompatible and osteogenic features of interest as possible cancellous bone replacement biomaterial for minimally invasive spinal surgery applications. PMID:19607944

  2. In vivo pH monitoring using boron doped diamond microelectrode and silver needles: Application to stomach disorder diagnosis

    NASA Astrophysics Data System (ADS)

    Fierro, Stphane; Seishima, Ryo; Nagano, Osamu; Saya, Hideyuki; Einaga, Yasuaki

    2013-11-01

    This study presents the in vivo electrochemical monitoring of pH using boron doped diamond (BDD) microelectrode and silver needles for potential application in medical diagnosis. Accurate calibration curve for pH determination were obtained through in vitro electrochemical measurements. The increase induced in stomach pH by treatment with pantoprazole was used to demonstrate that it is possible to monitor the pH in vivo using the simple and noninvasive system proposed herein. Using the results of the in vivo and in vitro experiments, a quantitative analysis of the increase in stomach pH is also presented. It is proposed that the catheter-free pH monitoring system presented in this study could be potentially employed in any biological environment.

  3. In vivo pH monitoring using boron doped diamond microelectrode and silver needles: application to stomach disorder diagnosis.

    PubMed

    Fierro, Stphane; Seishima, Ryo; Nagano, Osamu; Saya, Hideyuki; Einaga, Yasuaki

    2013-01-01

    This study presents the in vivo electrochemical monitoring of pH using boron doped diamond (BDD) microelectrode and silver needles for potential application in medical diagnosis. Accurate calibration curve for pH determination were obtained through in vitro electrochemical measurements. The increase induced in stomach pH by treatment with pantoprazole was used to demonstrate that it is possible to monitor the pH in vivo using the simple and noninvasive system proposed herein. Using the results of the in vivo and in vitro experiments, a quantitative analysis of the increase in stomach pH is also presented. It is proposed that the catheter-free pH monitoring system presented in this study could be potentially employed in any biological environment. PMID:24247214

  4. Combining whispering gallery mode lasers and microstructured optical fibers for in-vivo biosensing applications

    NASA Astrophysics Data System (ADS)

    François, A.; Rowland, K. J.; Reynolds, T.; Nicholls, S. J.; Monro, T. M.

    2013-10-01

    Whispering Gallery Modes (WGMs) have been widely studied for the past 20 years for various applications, including biological sensing. While the different WGM-based sensing approaches reported in the literature enable useful sensor characteristics, at present this technology is not yet mature, mainly for practical reasons. Our work has been focused on developing a simple, yet efficient, WGM-based sensing platform capable of being used as a dip sensor for in-vivo biosensing applications. We recently demonstrated that a dye-doped polymer microresonator, supporting WGMs, positioned onto the tip of a suspended core Microstructured Optical Fiber can be used as a dip sensor. In this architecture, the resonator is located on an air hole next to the fiber core at the fiber's tip, enabling a significant portion of the sphere to overlap with the guided light emerging from the fiber tip. This architecture offers significant benefits that have never been reported in the literature in terms of radiation efficiency, compared to the standard freestanding resonators, which arise from breaking the symmetry of the resonator. In addition to providing the remote excitation and collection of the WGMs' signal, the fiber also allows easy manipulation of the microresonator and the use this sensor in a dip sensing architecture, alleviating the need for a complex microfluidic interface. Here, we present our recent results on the microstructured fiber tip WGM-based sensor, including its lasing behavior and enhancement of the radiation efficiency as a function of the position of the resonator on the fiber tip. We also show that this platform can be used for clinical diagnostics and applying this technology to the detection of Troponin T, an acute myocardial infarction biomarker, down to a concentration of 7.4 pg/mL.

  5. Skin imaged by femtosecond laser irradiation: a risk assessment for in vivo applications

    NASA Astrophysics Data System (ADS)

    Fischer, F.; Volkmer, B.; Puschmann, S.; Greinert, R.; Breitbart, W.; Kiefer, J.; Wepf, R.

    2006-04-01

    During the last couple of years new imaging techniques using femtosecond lasers (fs-lasers) in the near infrared spectral range evolved for a variety of in vitro applications. We wanted to know, whether fs-lasers have a non-invasive imaging potential for in vivo applications for human skin. So far, little is known about possible risks of this irradiation type. To estimate the risk of irradiation damage in human skin we used a "biological dosimeter" in this investigation. We irradiated fresh human skin samples with both an fs-laser and a solar simulator (UV-source) for comparison. DNA damage introduced in the epidermis was evaluated using fluorescent antibodies against cyclobutane-pyrimidin-dimers (CPDs) in combination with immuno-fluorescence image analysis. Various fs-irradiation regimes were evaluated differing in laser power and step width of horizontal irradiation scans. When using 15 mW or 30 mW fs-laser power combined with horizontal irradiation scans applied every 5 mm in depth around the epidermal-dermal junction no induction of CPDs was found. However, induction of CPDs could be seen using 60 mW laser power and 5 ?m step width. Narrowing the step width to 1 mm and using increasing laser power (up to 35 mW) from the surface of the skin to the epidermis led to CPD formation, too. Quantitative comparison of CPD production at various laser regimes with CPD production using a solar simulator was done. We could show that the number of CPDs formed by the 60 mW laser irradiation regime is comparable to an UV-irradiation giving 0.6 MED (minimal erythemal dose). The smaller step width laser irradiation regime (1 ?m step width and up to 35 mW) was comparable to a UV-irradiation regime resulting in 0.45 MED.

  6. Application of synthetic photostable retinoids induces novel limb and facial phenotypes during chick embryogenesis in vivo

    PubMed Central

    Lopez-Real, R E; Budge, J J R; Marder, T B; Whiting, A; Hunt, P N; Przyborski, S A

    2014-01-01

    We have recently developed a range of synthetic retinoid analogues which include the compounds EC23 and EC19. They are stable on exposure to light and are predicted to be resistant to the normal metabolic processes involved in the inactivation of retinoids in vivo. Based on the position of the terminal carboxylic acid groups in the compounds we suggest that EC23 is a structural analogue of all-trans retinoic acid (ATRA), and EC19 is an analogue of 13-cis retinoic acid. Their effects on the differentiation of pluripotent stem cells has been previously described in vitro and are consistent with this hypothesis. We present herein the first description of the effects of these molecules in vivo. Retinoids were applied to the anterior limb buds of chicken embryos in ovo via ion-exchange beads. We found that retinoid EC23 produces effects on the wing digits similar to ATRA, but does so at two orders of magnitude lower concentration. When larger quantities of EC23 are applied, a novel phenotype is obtained involving production of multiple digit 1s on the anterior limb. This corresponds to differential effects of ATRA and EC23 on sonic hedgehog (shh) expression in the developing limb bud. With EC23 application we also find digit 1 phenotypes similar to thumb duplications described in the clinical literature. EC23 and ATRA are shown to have effects on the entire proximaldistal axis of the limb, including hitherto undescribed effects on the scapula. This includes suppression of expression of the scapula marker Pax1. EC23 also produces effects similar to those of ATRA on the developing face, producing reductions of the upper beak at concentrations two orders of magnitude lower than ATRA. In contrast, EC19, which is structurally very similar to EC23, has novel, less severe effects on the face and rarely alters limb development. EC19 and ATRA are effective at similar concentrations. These results further demonstrate the ability of retinoids to influence embryonic development. Moreover, EC23 represents a useful new tool to investigate developmental processes and probe the mechanisms underlying congenital abnormalities in vertebrates including man. PMID:24303996

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

    NASA Astrophysics Data System (ADS)

    Patel, Shreyas J.

    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.

  8. Characterization of in vivo strain in the rat tibia during external application of a four-point bending load.

    PubMed

    Akhter, M P; Raab, D M; Turner, C H; Kimmel, D B; Recker, R R

    1992-10-01

    This paper describes a technique for characterizing strains and stresses induced in vivo in the rat tibia during application of an external four-point bending load. An external load was applied through the muscle and soft tissue with a four-point bending device, to induce strain in a 11 mm section of the right tibiae of ten adult female Sprague-Dawley rats. Induced strains were measured in vivo on the lateral surface of the tibia. Inter-rat difference, leg positioning and strain gage placement were evaluated as sources of variability of applied strains. Beam bending theory was used to predict externally induced in vivo strains. Finite element analysis was used to quantify the magnitude of shear stresses induced by this type of loading. There was a linear relationship between applied load and induced in vivo strains. In vivo strains induced by external loading were linearly correlated (R2 = 0.87) with the strains calculated using beam bending theory. The finite element analysis predicted shear stresses at less than 10% of the longitudinal stresses resulting from four-point bending. Strains predicted along the tibia by finite element analysis and beam bending theory were well-correlated. Inter-rat variability due to tibia size and shape difference was the most important source of variation in induced strain (CV = 21.6%). Leg positioning was less important (CV = 9.5%). PMID:1400526

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

    PubMed Central

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

    2015-01-01

    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

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

    PubMed

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

    2015-01-01

    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

  11. Synthesis of luminescent near-infrared AgInS2 nanocrystals as optical probes for in vivo applications.

    PubMed

    Liu, Liwei; Hu, Rui; Roy, Indrajit; Lin, Guimiao; Ye, Ling; Reynolds, Jessica L; Liu, Jianwei; Liu, Jing; Schwartz, Stanley A; Zhang, Xihe; Yong, Ken-Tye

    2013-01-01

    Near infrared quantum dots have been receiving great attention as fluorescent optical probes for in vivo imaging applications. In this contribution, we report the synthesis and surface functionalization of cadmium free ternary AgInS2 nanocrystals emitting in the near infrared range for successful in vitro and in vivo bioimaging applications. The FDA approved triblock copolymer Pluronic F127 was used to encapsulate the nanocrystals and made them dispersible in aqueous solution. By employing a whole body small animal optical imaging setup, we were able to use the AgInS2 nanocrystals formulation for passive targeted delivery to the tumor site. The ultra-small crystal size, near-infrared emitting luminescence, and high quantum yield make the AgInS2 nanocrystals an attractive candidate as a biological contrast agent for cancer sensing and imaging. PMID:23422953

  12. A Multimode Optical Imaging System for Preclinical Applications In Vivo: Technology Development, Multiscale Imaging, and Chemotherapy Assessment

    PubMed Central

    Hwang, Jae Youn; Wachsmann-Hogiu, Sebastian; Ramanujan, V. Krishnan; Ljubimova, Julia; Gross, Zeev; Gray, Harry B.; Medina-Kauwe, Lali K.; Farkas, Daniel L.

    2012-01-01

    Purpose Several established optical imaging approaches have been applied, usually in isolation, to preclinical studies; however, truly useful in vivo imaging may require a simultaneous combination of imaging modalities to examine dynamic characteristics of cells and tissues. We developed a new multimode optical imaging system designed to be application-versatile, yielding high sensitivity, and specificity molecular imaging. Procedures We integrated several optical imaging technologies, including fluorescence intensity, spectral, lifetime, intravital confocal, two-photon excitation, and bioluminescence, into a single system that enables functional multiscale imaging in animal models. Results The approach offers a comprehensive imaging platform for kinetic, quantitative, and environmental analysis of highly relevant information, with micro-to-macroscopic resolution. Applied to small animals in vivo, this provides superior monitoring of processes of interest, represented here by chemo-/nanoconstruct therapy assessment. Conclusions This new system is versatile and can be optimized for various applications, of which cancer detection and targeted treatment are emphasized here. PMID:21874388

  13. Selective perturbation of in vivo linear energy transfer using high- Z vaginal applicators for Cf-252 brachytherapy

    NASA Astrophysics Data System (ADS)

    Rivard, M. J.; Evans, K. E.; Leal, L. C.; Kirk, B. L.

    2004-01-01

    Californium-252 ( 252Cf) brachytherapy sources emit both neutrons and photons, and have the potential to vastly improve the current standard-of-practice for brachytherapy. While hydrogenous materials readily attenuate the 252Cf fission energy neutrons, high- Z materials are utilized to attenuate the 252Cf gamma-rays. These differences in shielding materials may be exploited when treating with a vaginal applicator to possibly improve patient survival through perturbation of the in vivo linear energy transfer radiation.

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

    NASA Astrophysics Data System (ADS)

    Ispas, Cristina R.

    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.

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

    SciTech Connect

    Rempp, Hansjoerg; Scharpf, Marcus; Voigtlaender, Matthias; Schraml, Christina; Schmidt, Diethard; Fend, Falko; Claussen, Claus D.; Enderle, Markus D.; Pereira, Philippe L.; Clasen, Stephan

    2011-02-15

    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.

  16. 3D in vivo imaging of rat hearts by high frequency ultrasound and its application in myofiber orientation wrapping

    NASA Astrophysics Data System (ADS)

    Qin, Xulei; Wang, Silun; Shen, Ming; Zhang, Xiaodong; Lerakis, Stamatios; Wagner, Mary B.; Fei, Baowei

    2015-03-01

    Cardiac ultrasound plays an important role in the imaging of hearts in basic cardiovascular research and clinical examinations. 3D ultrasound imaging can provide the geometry or motion information of the heart. Especially, the wrapping of cardiac fiber orientations to the ultrasound volume could supply useful information on the stress distributions and electric action spreading. However, how to acquire 3D ultrasound volumes of the heart of small animals in vivo for cardiac fiber wrapping is still a challenging problem. In this study, we provide an approach to acquire 3D ultrasound volumes of the rat hearts in vivo. The comparison between both in vivo and ex vivo geometries indicated 90.1% Dice similarity. In this preliminary study, the evaluations of the cardiac fiber orientation wrapping errors were 24.7° for the acute angle error and were 22.4° for the inclination angle error. This 3D ultrasound imaging and fiber orientation estimation technique have potential applications in cardiac imaging.

  17. 3D in vivo imaging of rat hearts by high frequency ultrasound and its application in myofiber orientation wrapping

    PubMed Central

    Qin, Xulei; Wang, Silun; Shen, Ming; Zhang, Xiaodong; Lerakis, Stamatios; Wagner, Mary B.; Fei, Baowei

    2015-01-01

    Cardiac ultrasound plays an important role in the imaging of hearts in basic cardiovascular research and clinical examinations. 3D ultrasound imaging can provide the geometry or motion information of the heart. Especially, the wrapping of cardiac fiber orientations to the ultrasound volume could supply useful information on the stress distributions and electric action spreading. However, how to acquire 3D ultrasound volumes of the heart of small animals in vivo for cardiac fiber wrapping is still a challenging problem. In this study, we provide an approach to acquire 3D ultrasound volumes of the rat hearts in vivo. The comparison between both in vivo and ex vivo geometries indicated 90.1% Dice similarity. In this preliminary study, the evaluations of the cardiac fiber orientation wrapping errors were 24.7 for the acute angle error and were 22.4 for the inclination angle error. This 3D ultrasound imaging and fiber orientation estimation technique have potential applications in cardiac imaging. PMID:26412926

  18. Application of electrical stimulation for functional tissue engineering in vitro and in vivo

    NASA Technical Reports Server (NTRS)

    Radisic, Milica (Inventor); Park, Hyoungshin (Inventor); Langer, Robert (Inventor); Freed, Lisa (Inventor); Vunjak-Novakovic, Gordana (Inventor)

    2013-01-01

    The present invention provides new methods for the in vitro preparation of bioartificial tissue equivalents and their enhanced integration after implantation in vivo. These methods include submitting a tissue construct to a biomimetic electrical stimulation during cultivation in vitro to improve its structural and functional properties, and/or in vivo, after implantation of the construct, to enhance its integration with host tissue and increase cell survival and functionality. The inventive methods are particularly useful for the production of bioartificial equivalents and/or the repair and replacement of native tissues that contain electrically excitable cells and are subject to electrical stimulation in vivo, such as, for example, cardiac muscle tissue, striated skeletal muscle tissue, smooth muscle tissue, bone, vasculature, and nerve tissue.

  19. Assessment of the Therapeutic Potential of Metallothionein-II Application in Focal Cerebral Ischemia In Vitro and In Vivo

    PubMed Central

    Freyer, Dorette; Trendelenburg, George

    2015-01-01

    Metallothionein-II (MT-II) is an ubiquitously expressed small-molecular-weight protein and highly induced in various species and tissues upon stress, inflammation, and ischemia. MT-deficiency exacerbates ischemic injury in rodent stroke models in vitro and in vivo. However, there is conflicting data on the potential neuroprotective effect of exogenously applied metallothionein. Thus, we applied MT-II in an in vitro stroke model and intraperitoneally (i.p.) in two in vivo standard models of transient middle cerebral artery occlusion (MCAO) (a stringent one [60min MCAO/48h reperfusion] and a mild one [30min MCAO/72h reperfusion]), as well as i.v. together with recombinant tissue plasminogen activator (rtPA) to evaluate if exogenous MT-II-application protects against ischemic stroke. Whereas MT-II did not protect against 60min MCAO, there was a significant reduction of direct and indirect infarct volumes and neurological deficit in the MT-II (i.p.) treated animals in the mild model at 3d after MCAO. Furthermore, MT-II also improved survival of the mice after MCAO, suppressed TNF-? mRNA induction in ischemic brain tissue, and protected primary neuronal cells against oxygen-glucose-deprivation in vitro. Thus, exogenous application of MT-II protects against ischemic injury in vitro and in vivo. However, long-term studies with different species and larger sampling sizes are required before a clinical use can be envisaged. PMID:26658636

  20. In vitro topical application and in vivo pharmacodynamic evaluation of nonivamide hydrogels using Wistar rat as an animal model.

    PubMed

    Fang, Jia-You; Leu, Yann-Lii; Wang, Ying-Yue; Tsai, Yi-Hung

    2002-06-01

    Nonivamide, a so-called synthetic capsaicin, is a substitute for capsaicin which has a similar chemical structure and pharmacological activities as those of capsaicin. The purposes of this study were to explore the in vivo pharmacodynamic responses of nonivamide in hydrogels using Wistar rat as an animal model and to correlate the in vivo results with in vitro topical application. The incorporation of Pluronic F-127 polymer into hydrogels resulted in retarded release of nonivamide. Chitosan and carboxymethylcellulose hydrogels produced higher levels of in vitro nonivamide permeation and skin distribution. The in vivo effects of nonivamide on skin perturbation and vasodilation were found to differ depending on dose and duration after topical application. Quantification of transepidermal water loss was demonstrated to correlate with the measured in vitro skin distribution of nonivamide. The various doses of nonivamide in the hydrogels did not markedly influence erythematous reactions of skin as determined by colorimetric measurements. Hydrogel formulations of nonivamide delivered more drug to the skin and produced greater pharmacodynamic activities than did cream bases of capsaicin. PMID:12036718

  1. Application of the front detection photopiroelectric configuration to the study of in vivo human skin

    NASA Astrophysics Data System (ADS)

    Gutierrez-Juarez, G.; Pichardo-Molina, J. L.; Rocha-Osornio, L. N.; Huerta-Franco, R.; Ivanov, R.; Huerta-Franco, B.; Cordova-Fraga, T.; Vargas-Luna, M.

    2005-06-01

    We report a novel method for measurements in vivo of the penetration of topically applied substances by inverse photopyroelectric configuration. This configuration was used to obtain the thermal effusivity, as a function of time, of in vivo human skin with ointments. This thermal magnitude was employed to characterize the penetration on the anterior-face of the volunteers forearm. This thermal effusivity was fitted with an exponential function in order to obtain a parameter (characteristic time) for the penetration. The substances used were a sunscreen and Vick Vaporub ointment. We found that the sunscreen have a characteristic time bigger that the Vick Vaporub ointment. The feasibility of skin hydration studies are discussed.

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

    PubMed Central

    2013-01-01

    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 mouses 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 mouses breathing and movements, meanwhile, using less sampling data than FBP while maintaining the same high quality. PMID:23898866

  3. 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...

  4. Applications of stable, nonradioactive isotope tracers in in vivo human metabolic research.

    PubMed

    Kim, Il-Young; Suh, Sang-Hoon; Lee, In-Kyu; Wolfe, Robert R

    2016-01-01

    The human body is in a constant state of turnover, that is, being synthesized, broken down and/or converted to different compounds. The dynamic nature of in vivo kinetics of human metabolism at rest and in stressed conditions such as exercise and pathophysiological conditions such as diabetes and cancer can be quantitatively assessed with stable, nonradioactive isotope tracers in conjunction with gas or liquid chromatography mass spectrometry and modeling. Although measurements of metabolite concentrations have been useful as general indicators of one's health status, critical information on in vivo kinetics of metabolites such as rates of production, appearance or disappearance of metabolites are not provided. Over the past decades, stable, nonradioactive isotope tracers have been used to provide information on dynamics of specific metabolites. Stable isotope tracers can be used in conjunction with molecular and cellular biology tools, thereby providing an in-depth dynamic assessment of metabolic changes, as well as simultaneous investigation of the molecular basis for the observed kinetic responses. In this review, we will introduce basic principles of stable isotope methodology for tracing in vivo kinetics of human or animal metabolism with examples of quantifying certain aspects of in vivo kinetics of carbohydrate, lipid and protein metabolism. PMID:26795236

  5. Applications of stable, nonradioactive isotope tracers in in vivo human metabolic research

    PubMed Central

    Kim, Il-Young; Suh, Sang-Hoon; Lee, In-Kyu; Wolfe, Robert R

    2015-01-01

    The human body is in a constant state of turnover, that is, being synthesized, broken down and/or converted to different compounds. The dynamic nature of in vivo kinetics of human metabolism at rest and in stressed conditions such as exercise and pathophysiological conditions such as diabetes and cancer can be quantitatively assessed with stable, nonradioactive isotope tracers in conjunction with gas or liquid chromatography mass spectrometry and modeling. Although measurements of metabolite concentrations have been useful as general indicators of one's health status, critical information on in vivo kinetics of metabolites such as rates of production, appearance or disappearance of metabolites are not provided. Over the past decades, stable, nonradioactive isotope tracers have been used to provide information on dynamics of specific metabolites. Stable isotope tracers can be used in conjunction with molecular and cellular biology tools, thereby providing an in-depth dynamic assessment of metabolic changes, as well as simultaneous investigation of the molecular basis for the observed kinetic responses. In this review, we will introduce basic principles of stable isotope methodology for tracing in vivo kinetics of human or animal metabolism with examples of quantifying certain aspects of in vivo kinetics of carbohydrate, lipid and protein metabolism. PMID:26795236

  6. A new strategy for in vivo spectral editing. Application to GABA editing using selective homonuclear polarization transfer spectroscopy

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Yang, Jehoon; Choi, In-Young; Li, Shizhe Steve; Chen, Zhengguang

    2004-10-01

    A novel single-shot in vivo spectral editing method is proposed in which the signal to be detected, is regenerated anew from the thermal equilibrium magnetization of a source to which it is J-coupled. The thermal equilibrium magnetization of the signal to be detected together with those of overlapping signals are suppressed by single-shot gradient dephasing prior to the signal regeneration process. Application of this new strategy to in vivo GABA editing using selective homonuclear polarization transfer allows complete suppression of overlapping creatine and glutathione while detecting the GABA-4 methylene resonance at 3.02 ppm with an editing yield similar to that of conventional editing methods. The NAA methyl group at 2.02 ppm was simultaneously detected and can be used as an internal navigator echo for correcting the zero order phase and frequency shifts and as an internal reference for concentration. This new method has been demonstrated for robust in vivo GABA editing in the rat brain and for study of GABA synthesis after acute vigabatrin administration.

  7. Synthesis, characterization, and application of reversible PDLLA-PEG-PDLLA copolymer thermogels in vitro and in vivo.

    PubMed

    Shi, Kun; Wang, Ya-Li; Qu, Ying; Liao, Jin-Feng; Chu, Bing-Yang; Zhang, Hua-Ping; Luo, Feng; Qian, Zhi-Yong

    2016-01-01

    In this study, a series of injectable thermoreversible and thermogelling PDLLA-PEG-PDLLA copolymers were developed and a systematic evaluation of the thermogelling system both in vitro and in vivo was performed. The aqueous PDLLA-PEG-PDLLA solutions above a critical gel concentration could transform into hydrogel spontaneously within 2?minutes around the body temperature in vitro or in vivo. Modulating the molecular weight, block length and polymer concentration could adjust the sol-gel transition behavior and the mechanical properties of the hydrogels. The gelation was thermally reversible due to the physical interaction of copolymer micelles and no crystallization formed during the gelation. Little cytotoxicity and hemolysis of this polymer was found, and the inflammatory response after injecting the hydrogel to small-animal was acceptable. In vitro and in vivo degradation experiments illustrated that the physical hydrogel could retain its integrity as long as several weeks and eventually be degraded by hydrolysis. A rat model of sidewall defect-bowel abrasion was employed, and a significant reduction of post-operative adhesion has been found in the group of PDLLA-PEG-PDLLA hydrogel-treated, compared with untreated control group and commercial hyaluronic acid (HA) anti-adhesion hydrogel group. As such, this PDLLA-PEG-PDLLA hydrogel might be a promising candidate of injectable biomaterial for medical applications. PMID:26752008

  8. Synthesis, characterization, and application of reversible PDLLA-PEG-PDLLA copolymer thermogels in vitro and in vivo

    PubMed Central

    Shi, Kun; Wang, Ya-Li; Qu, Ying; Liao, Jin-Feng; Chu, Bing-Yang; Zhang, Hua-Ping; Luo, Feng; Qian, Zhi-Yong

    2016-01-01

    In this study, a series of injectable thermoreversible and thermogelling PDLLA-PEG-PDLLA copolymers were developed and a systematic evaluation of the thermogelling system both in vitro and in vivo was performed. The aqueous PDLLA-PEG-PDLLA solutions above a critical gel concentration could transform into hydrogel spontaneously within 2 minutes around the body temperature in vitro or in vivo. Modulating the molecular weight, block length and polymer concentration could adjust the sol-gel transition behavior and the mechanical properties of the hydrogels. The gelation was thermally reversible due to the physical interaction of copolymer micelles and no crystallization formed during the gelation. Little cytotoxicity and hemolysis of this polymer was found, and the inflammatory response after injecting the hydrogel to small-animal was acceptable. In vitro and in vivo degradation experiments illustrated that the physical hydrogel could retain its integrity as long as several weeks and eventually be degraded by hydrolysis. A rat model of sidewall defect-bowel abrasion was employed, and a significant reduction of post-operative adhesion has been found in the group of PDLLA-PEG-PDLLA hydrogel-treated, compared with untreated control group and commercial hyaluronic acid (HA) anti-adhesion hydrogel group. As such, this PDLLA-PEG-PDLLA hydrogel might be a promising candidate of injectable biomaterial for medical applications. PMID:26752008

  9. A novel in vivo inducible expression system in Edwardsiella tarda for potential application in bacterial polyvalence vaccine.

    PubMed

    Mu, Wei; Guan, Lingyu; Yan, Yijian; Liu, Qin; Zhang, Yuanxing

    2011-12-01

    Recombinant bacterial vector vaccine is an attractive vaccination strategy to induce the immune response to a carried protective antigen, and the main concern of bacterial vector vaccine is to establish a stable antigen expression system in vector bacteria. Edwardsiella tarda is an important facultative intracellular pathogen of both animals and humans, and its attenuated derivates are excellent bacterial vectors for use in recombinant vaccine design. In this study, we design an in vivo inducible expression system in E. tarda and establish potential recombinant E. tarda vector vaccines. With wild type strain E. tarda EIB202 as a vector, 53 different bacteria-originated promoters were examined for iron-responsive transcription in vitro, and the promoters P(dps) and P(yncE) showed high transcription activity. The transcription profiles in vivo of two promoters were further assayed, and P(dps) revealed an enhanced in vivo inducible transcription in macrophage, larvae and adult zebra fish. The gapA34 gene, encoding the protective antigen GAPDH from the fish pathogen Aeromonas hydrophila LSA34, was introduced into the P(dps)-based protein expression system, and transformed into attenuated E. tarda strains. The resultant recombinant vector vaccine WED/pUTDgap was evaluated in turbot (Scophtalmus maximus). Over 60% of the vaccinated fish survived under the challenge with A. hydrophila LSA34 and E. tarda EIB202, suggesting that the P(dps)-based antigen delivery system had great potential in bacterial vector vaccine application. PMID:21964456

  10. In vivo elemental analysis by counting neutron-induced gamma rays for medical and biological applications

    NASA Astrophysics Data System (ADS)

    Kehayias, Joseph J.; Ma, Ruimei; Zhuang, Hong; Moore, Robert; Dowling, Lisa

    1995-03-01

    Non-invasive in vivo elemental analysis is a technique used to assess human body composition which is indicative of nutritional status and health condition. The in vivo measurement of the body's major elements is used for a variety of medical studies requiring the determination of the body's compartments (protein, fat, water, bone). Whole body gamma-ray counters, consisting of Nal(Tl) crystal detectors in a shielded room, are used for measuring in vivo the body's Ca, Cl, Na and P by delayed neutron activation analysis. Thermal neutrons from a moderated 238Pu-Be source are used for the measurement of total body nitrogen (and thus protein) and chlorine at low radiation exposure (0.80 mSv). The resulting high energy prompt gamma-rays from nitrogen (10.83 MeV) and chlorine (6.11 MeV) are detected simultaneously with the irradiation. Body fat (the main energy store) and fat distribution (which relates to risk for cardiovascular disease) are measured by detecting C and O in vivo through fast neutron inelastic scattering. A small sealed D-T neutron generator is used for the pulsed (4 - 8 KHz) production of fast neutrons. Carbon and oxygen are detected by counting the 4.44 and 6.13 MeV gamma-rays resulting from the inelastic scattering of the fast neutrons from the 12C and 16O nuclei, respectively. One use of this method is the systematic study of the mechanisms driving the age-associated depletion of the metabolizing, oxygen-consuming cellular compartment of the body. The understanding of this catabolism may suggest ways to maintain lean tissue and thus to preserve quality of life for the very old.

  11. Application of XRF to measure strontium in human bone in vivo

    SciTech Connect

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

    1982-01-01

    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.

  12. Miniature Uncooled Infrared Sensitive Detectors for in Vivo Biomedical Imaging Applications

    SciTech Connect

    Datskos, P. G.; Demos, S. G.; Rajic, S.

    1998-06-01

    Broadband infrared (OR) radiation detectors have been developed using miniature, inexpensive, mass produced microcantilevers capable of detecting temperature differences as small as lea(-6) K. Microcantilevers made out of semiconductor materials can be used either as uncurled photon or thermal detectors. Mounted on a probe mm in diameter a number of microcantilevers can be accommodated in the working channel of existing endoscopes for in vivo proximity focus measurements inside the human body.

  13. Two-photon excited fluorescence microscopy application for ex vivo investigation of ocular fundus samples

    NASA Astrophysics Data System (ADS)

    Peters, Sven; Hammer, Martin; Schweitzer, Dietrich

    2011-07-01

    Two-photon excited fluorescence (TPEF) imaging of ocular tissue has recently become a promising tool in ophthalmology for diagnostic and research purposes. The feasibility and the advantages of TPEF imaging, namely deeper tissue penetration and improved high-resolution imaging of microstructures, have been demonstrated lately using human ocular samples. The autofluorescence properties of endogenous fluorophores in ocular fundus tissue are well known from spectrophotometric analysis. But fluorophores, especially when it comes to fluorescence lifetime, typically display a dependence of their fluorescence properties on local environmental parameters. Hence, a more detailed investigation of ocular fundus autofluorescence ideally in vivo is of utmost interest. The aim of this study is to determine space-resolved the stationary and time-resolved fluorescence properties of endogenous fluorophores in ex vivo porcine ocular fundus samples by means of two-photon excited fluorescence spectrum and lifetime imaging microscopy (FSIM/FLIM). By our first results, we characterized the autofluorescence of individual anatomical structures of porcine retina samples excited at 760 nm. The fluorescence properties of almost all investigated retinal layers are relatively homogenous. But as previously unknown, ganglion cell bodies show a significantly shorter fluorescence lifetime compared to the adjacent mueller cells. Since all retinal layers exhibit bi-exponential autofluorescence decays, we were able to achieve a more precise characterization of fluorescence properties of endogenous fluorophores compared to a present in vivo FLIM approach by confocal scanning laser ophthalmoscope (cSLO).

  14. Measurement of passive skeletal muscle mechanical properties in vivo: recent progress, clinical applications, and remaining challenges.

    PubMed

    Bilston, Lynne E; Tan, Kristy

    2015-02-01

    The ability to measure and quantify the properties of skeletal muscle in vivo as a method for understanding its complex physiological and pathophysiological behavior is important in numerous clinical settings, including rehabilitation. However, this remains a challenge to date due to the lack of a "gold standard" technique. Instead, there are a myriad of measuring techniques each with its own set of pros and cons. This review discusses the current state-of-the-art in elastography imaging techniques, i.e., ultrasound and magnetic resonance elastography, as applied to skeletal muscle, and briefly reviews other methods of measuring muscle mechanical behavior in vivo. While in vivo muscle viscoelastic properties can be measured, these techniques are largely limited to static or quasistatic measurements. Emerging elastography techniques are able to quantify muscle anisotropy and large deformation effects on stiffness, but, validation and optimization of these newer techniques is required. The development of reliable values for the mechanical properties of muscle across the population using these techniques are required to enable them to become more useful in rehabilitation and other clinical settings. PMID:25404536

  15. In-vitro Optimization of Nanoparticle-Cell Labeling Protocols for In-vivo Cell Tracking Applications

    PubMed Central

    Betzer, Oshra; Meir, Rinat; Dreifuss, Tamar; Shamalov, Katerina; Motiei, Menachem; Shwartz, Amit; Baranes, Koby; Cohen, Cyrille J.; Shraga-Heled, Niva; Ofir, Racheli; Yadid, Gal; Popovtzer, Rachela

    2015-01-01

    Recent advances in theranostic nanomedicine can promote stem cell and immune cell-based therapy. Gold nanoparticles (GNPs) have been shown to be promising agents for in-vivo cell-tracking in cell-based therapy applications. Yet a crucial challenge is to develop a reliable protocol for cell upload with, on the one hand, sufficient nanoparticles to achieve maximum visibility of cells, while on the other hand, assuring minimal effect of particles on cell function and viability. Previous studies have demonstrated that the physicochemical parameters of GNPs have a critical impact on their efficient uptake by cells. In the current study we have examined possible variations in GNP uptake, resulting from different incubation period and concentrations in different cell-lines. We have found that GNPs effectively labeled three different cell-lines - stem, immune and cancer cells, with minimal impairment to cell viability and functionality. We further found that uptake efficiency of GNPs into cells stabilized after a short period of time, while GNP concentration had a significant impact on cellular uptake, revealing cell-dependent differences. Our results suggest that while heeding the slight variations within cell lines, modifying the loading time and concentration of GNPs, can promote cell visibility in various nanoparticle-dependent in-vivo cell tracking and imaging applications. PMID:26507853

  16. Simple and effective exercise design for assessing in vivo mitochondrial function in clinical applications using 31P magnetic resonance spectroscopy

    PubMed Central

    Sleigh, Alison; Lupson, Victoria; Thankamony, Ajay; Dunger, David B.; Savage, David B.; Carpenter, T. Adrian; Kemp, Graham J.

    2016-01-01

    The growing recognition of diseases associated with dysfunction of mitochondria poses an urgent need for simple measures of mitochondrial function. Assessment of the kinetics of replenishment of the phosphocreatine pool after exercise using 31P magnetic resonance spectroscopy can provide an in vivo measure of mitochondrial function; however, the wider application of this technique appears limited by complex or expensive MR-compatible exercise equipment and protocols not easily tolerated by frail participants or those with reduced mental capacity. Here we describe a novel in-scanner exercise method which is patient-focused, inexpensive, remarkably simple and highly portable. The device exploits an MR-compatible high-density material (BaSO4) to form a weight which is attached directly to the ankle, and a one-minute dynamic knee extension protocol produced highly reproducible measurements of post-exercise PCr recovery kinetics in both healthy subjects and patients. As sophisticated exercise equipment is unnecessary for this measurement, our extremely simple design provides an effective and easy-to-implement apparatus that is readily translatable across sites. Its design, being tailored to the needs of the patient, makes it particularly well suited to clinical applications, and we argue the potential of this method for investigating in vivo mitochondrial function in new cohorts of growing clinical interest. PMID:26751849

  17. Simple and effective exercise design for assessing in vivo mitochondrial function in clinical applications using (31)P magnetic resonance spectroscopy.

    PubMed

    Sleigh, Alison; Lupson, Victoria; Thankamony, Ajay; Dunger, David B; Savage, David B; Carpenter, T Adrian; Kemp, Graham J

    2016-01-01

    The growing recognition of diseases associated with dysfunction of mitochondria poses an urgent need for simple measures of mitochondrial function. Assessment of the kinetics of replenishment of the phosphocreatine pool after exercise using (31)P magnetic resonance spectroscopy can provide an in vivo measure of mitochondrial function; however, the wider application of this technique appears limited by complex or expensive MR-compatible exercise equipment and protocols not easily tolerated by frail participants or those with reduced mental capacity. Here we describe a novel in-scanner exercise method which is patient-focused, inexpensive, remarkably simple and highly portable. The device exploits an MR-compatible high-density material (BaSO4) to form a weight which is attached directly to the ankle, and a one-minute dynamic knee extension protocol produced highly reproducible measurements of post-exercise PCr recovery kinetics in both healthy subjects and patients. As sophisticated exercise equipment is unnecessary for this measurement, our extremely simple design provides an effective and easy-to-implement apparatus that is readily translatable across sites. Its design, being tailored to the needs of the patient, makes it particularly well suited to clinical applications, and we argue the potential of this method for investigating in vivo mitochondrial function in new cohorts of growing clinical interest. PMID:26751849

  18. Glycine enhances extracellular 45Ca2+ response to NMDA application investigated with microdialysis of rabbit hippocampus in vivo.

    PubMed

    Lazarewicz, J W; Sali?ska, E; Puka, M

    1992-01-01

    This study evaluates the role of glycine in in vivo modulation of the activity of excitatory amino acid receptors sensitive to N-methyl-D-aspartate (NMDA) in the rabbit hippocampus. Changes of extracellular calcium concentration were studied by the microdialysis technique combined with 45Ca-utilizing clearance method. The steady state level of amino acids in the dialysate was analyzed with HPLC. Pharmacologically active substances were applied directly to the hippocampus via the dialysis medium. Glycine concentration in the extracellular fluid of the hippocampus was in the range of 10(-5) M. Application of NMDA induced a drop of calcium concentration in the extracellular compartment of the hippocampus. This effect was inhibited by 7-Cl-kynurenic acid, an antagonist of glycine binding site on the NMDA receptors. Application of glycine and D-serine to the dialysis medium did not interfere with the basal level of extracellular calcium in the hippocampus, but resulted in an enhancement of the NMDA-induced decrease of calcium concentration. These results indicate that in the hippocampus the NMDA receptors are under constant positive modulation by endogenous glycine. Since glycine binding sites on the NMDA receptors are not saturated by an endogenous ligand, glycine may play a role in regulation of the NMDA receptor activity in the hippocampus in vivo. PMID:1414510

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

    PubMed

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

    2010-01-01

    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

  20. In vivo assessment of neurotransmitters and modulators with magnetic resonance spectroscopy: application to schizophrenia.

    PubMed

    Wijtenburg, S Andrea; Yang, Shaolin; Fischer, Bernard A; Rowland, Laura M

    2015-04-01

    In vivo measurement of neurotransmitters and modulators is now feasible with advanced proton magnetic resonance spectroscopy ((1)H MRS) techniques. This review provides a basic tutorial of MRS, describes the methods available to measure brain glutamate, glutamine, γ-aminobutyric acid, glutathione, N-acetylaspartylglutamate, glycine, and serine at magnetic field strengths of 3T or higher, and summarizes the neurochemical findings in schizophrenia. Overall, (1)H MRS holds great promise for producing biomarkers that can serve as treatment targets, prediction of disease onset, or illness exacerbation in schizophrenia and other brain diseases. PMID:25614132

  1. Windows on the Human Body – in Vivo High-Field Magnetic Resonance Research and Applications in Medicine and Psychology

    PubMed Central

    Moser, Ewald; Meyerspeer, Martin; Fischmeister, Florian Ph. S.; Grabner, Günther; Bauer, Herbert; Trattnig, Siegfried

    2010-01-01

    Analogous to the evolution of biological sensor-systems, the progress in “medical sensor-systems”, i.e., diagnostic procedures, is paradigmatically described. Outstanding highlights of this progress are magnetic resonance imaging (MRI) and spectroscopy (MRS), which enable non-invasive, in vivo acquisition of morphological, functional, and metabolic information from the human body with unsurpassed quality. Recent achievements in high and ultra-high field MR (at 3 and 7 Tesla) are described, and representative research applications in Medicine and Psychology in Austria are discussed. Finally, an overview of current and prospective research in multi-modal imaging, potential clinical applications, as well as current limitations and challenges is given. PMID:22219684

  2. Luminescent magnetic quantum dots for in vitro/in vivo imaging and applications in therapeutics.

    PubMed

    Acharya, Amitabha

    2013-06-01

    The quest for design of newer/advanced methods for medical diagnosis and targeted therapeutics are of utmost interest and challenging too, because of its importance in clinical diagnosis. Currently available diagnosis methodologies have their own disadvantages. These shortcomings can be overcome by using multimodal imaging systems where two or more imaging modalities may be coupled. Nanoparticles being widely studied for targeted drug delivery and as biological contrasting agents, might play a decisive role in such findings. This review is focused towards the ongoing research in the area of hybrid nanocomposites which can be used for both as MRI contrasting agent (magnetic nanoparticles) and molecular imaging studies (using fluorescent quantum dots) at in vitro and in vivo level. Though several reports are available in literature for such bimodal imaging systems, their clinical trials are very restricted, possibly because of the lack of communication between the in vitro and in vivo studies. This review is expected to bridge the gap between such studies. PMID:23862405

  3. Application of laser scan microscopy in vivo for wound healing characterization

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

    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.

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

    PubMed Central

    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

    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

  5. In vivo application of poly-3-hydroxyoctanoate as peripheral nerve graft

    PubMed Central

    Hazer, D. Burcu; Bal, Ercan; Nurlu, Gülay; Benli, Kemal; Balci, Serdar; Öztürk, Feral; Hazer, Baki

    2013-01-01

    Objective: This study aims to investigate the degree of biocompatibility and neuroregeneration of a polymer tube, poly-3-hydroxyoctanoate (PHO) in nerve gap repair. Methods: Forty Wistar Albino male rats were randomized into two groups: autologous nerve gap repair group and PHO tube repair group. In each group, a 10-mm right sciatic nerve defect was created and reconstructed accordingly. Neuroregeneration was studied by sciatic function index (SFI), electromyography, and immunohistochemical studies on Days 7, 21, 45 and 60 of implantation. Biocompatibility was analyzed by the capsule formation around the conduit. Biodegradation was analyzed by the molecular weight loss in vivo. Results: Electrophysiological and histomorphometric assessments demonstrated neuroregeneration in both groups over time. In the experimental group, a straight alignment of the Schwann cells parallel to the axons was detected. However, autologous nerve graft seems to have a superior neuroregeneration compared to PHO grafts. Minor biodegradation was observed in PHO conduit at the end of 60 d. Conclusions: Although neuroregeneration is detected in PHO grafts with minor degradation in 60 d, autologous nerve graft is found to be superior in axonal regeneration compared to PHO nerve tube grafts. PHO conduits were found to create minor inflammatory reaction in vivo, resulting in good soft tissue response. PMID:24190445

  6. Anti-Bladder-Tumor Effect of Baicalein from Scutellaria baicalensis Georgi and Its Application In Vivo.

    PubMed

    Wu, Jin-Yi; Tsai, Kun-Wei; Li, Yi-Zhen; Chang, Yi-Sheng; Lai, Yi-Chien; Laio, Yu-Han; Wu, Jiann-Der; Liu, Yi-Wen

    2013-01-01

    Some phytochemicals with the characteristics of cytotoxicity and/or antimetastasis have generated intense interest among the anticancer studies. In this study, a natural flavonoid baicalein was evaluated in bladder cancer in vitro and in vivo. Baicalein inhibits 5637 cell proliferation. It arrests cells in G1 phase at 100? ? M and in S phase below 75? ? M. The protein expression of cyclin B1 and cyclin D1 is reduced by baicalein. Baicalein-induced p-ERK plays a minor role in cyclin B1 reduction. Baicalein-inhibited p65NF- ? B results in reduction of cell growth. Baicalein-induced pGSK(ser9) has a little effect in increasing cyclin B1/D1 expression instead. The translation inhibitor cycloheximide blocks baicalein-reduced cyclin B1, suggesting that the reduction is caused by protein synthesis inhibition. On the other hand, neither cycloheximide nor proteasome inhibitor MG132 completely blocks baicalein-reduced cyclin D1, suggesting that baicalein reduces cyclin D1 through protein synthesis inhibition and proteasomal degradation activation. In addition, baicalein also inhibits cell invasion by inhibiting MMP-2 and MMP-9 mRNA expression and activity. In mouse orthotopic bladder tumor model, baicalein slightly reduces tumor size but with some hepatic toxicity. In summary, these results demonstrate the anti-bladder-tumor properties of the natural compound baicalein which shows a slight anti-bladder-tumor effect in vivo. PMID:23573134

  7. Anti-Bladder-Tumor Effect of Baicalein from Scutellaria baicalensis Georgi and Its Application In Vivo

    PubMed Central

    Wu, Jin-Yi; Li, Yi-Zhen; Chang, Yi-Sheng; Lai, Yi-Chien; Laio, Yu-Han; Wu, Jiann-Der; Liu, Yi-Wen

    2013-01-01

    Some phytochemicals with the characteristics of cytotoxicity and/or antimetastasis have generated intense interest among the anticancer studies. In this study, a natural flavonoid baicalein was evaluated in bladder cancer in vitro and in vivo. Baicalein inhibits 5637 cell proliferation. It arrests cells in G1 phase at 100??M and in S phase below 75??M. The protein expression of cyclin B1 and cyclin D1 is reduced by baicalein. Baicalein-induced p-ERK plays a minor role in cyclin B1 reduction. Baicalein-inhibited p65NF-?B results in reduction of cell growth. Baicalein-induced pGSK(ser9) has a little effect in increasing cyclin B1/D1 expression instead. The translation inhibitor cycloheximide blocks baicalein-reduced cyclin B1, suggesting that the reduction is caused by protein synthesis inhibition. On the other hand, neither cycloheximide nor proteasome inhibitor MG132 completely blocks baicalein-reduced cyclin D1, suggesting that baicalein reduces cyclin D1 through protein synthesis inhibition and proteasomal degradation activation. In addition, baicalein also inhibits cell invasion by inhibiting MMP-2 and MMP-9 mRNA expression and activity. In mouse orthotopic bladder tumor model, baicalein slightly reduces tumor size but with some hepatic toxicity. In summary, these results demonstrate the anti-bladder-tumor properties of the natural compound baicalein which shows a slight anti-bladder-tumor effect in vivo. PMID:23573134

  8. Novel system for in vivo biotinylation and its application to crab antimicrobial protein scygonadin

    PubMed Central

    Sousa, Rui

    2015-01-01

    BirA is a biotin ligase from Escherichia coli that specifically biotinylates a lysine side-chain within a 15-amino acid acceptor peptide (also known as Avi-tag). We developed a protocol for producing recombinant BirA ligase in E. coli for in vitro biotinylation (Li and Sousa, Prot Expr Purif, 82:162167, 2012) in which the target protein was expressed as both thioredoxin and MBP fusions, and was released by TEV protease-mediated cleavage. The liberated ligase and the fusion proteins were enzymatically active. Based on that observation, we have now developed a novel system for in vivo biotinylation by co-expressing the Avi-tagged target protein with the MBPBirA fusion. The effectiveness of this system was demonstrated by the successful in vivo labeling of antimicrobial protein, scygonadin. This new system shows improved efficiency compared with pre-existing one and this is likely attributed to the high expression level and solubility of the co-expressed MBPBirA. PMID:22566209

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

    SciTech Connect

    Thor, A.D.; Edgerton, S.M. )

    1989-10-01

    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.

  10. In-vivo high resolution corneal imaging and analysis on animal models for clinical applications

    NASA Astrophysics Data System (ADS)

    Hong, Jesmond; Shinoj, V. K.; Murukeshan, V. M.; Baskaran, M.; Aung, Tin

    2015-07-01

    A simple and low cost optical probe system for the high resolution imaging of the cornea is proposed, based on a Gaussian beam epi-illumination configuration. Corneal topography is obtained by moving the scanning spot across the eye in a raster fashion whereas pachymetry data is achieved by reconstructing the images obtained at different depths. The proposed prototype has been successfully tested on porcine eye samples ex vivo and subsequently on laboratory animals, such as the New Zealand White Rabbit, in vivo. This proposed system and methodology pave the way for realizing a simple and inexpensive optical configuration for pachymetry and keratometry readings, with achievable resolution up to the cellular level. This novel and non-contact high resolution imaging modality demonstrates high intraobserver reproducibility and repeatability. Together with its sophisticated data analysis strategies and safety profile, it is believed to complement existing imaging modalities in the assessment and evaluation of corneal diseases, which enable a decrease in morbidity and improvement in the effectiveness of subsequent treatment.

  11. Intelligent spectral signature bio-imaging in vivo for surgical applications

    NASA Astrophysics Data System (ADS)

    Jeong, Jihoon; Frykman, Philip K.; Gaon, Mark; Chung, Alice P.; Lindsley, Erik H.; Hwang, Jae Y.; Farkas, Daniel L.

    2007-02-01

    Multi-spectral imaging provides digital images of a scene or object at a large, usually sequential number of wavelengths, generating precise optical spectra at every pixel. We use the term "spectral signature" for a quantitative plot of optical property variations as a function of wavelengths. We present here intelligent spectral signature bio-imaging methods we developed, including automatic signature selection based on machine learning algorithms and database search-based automatic color allocations, and selected visualization schemes matching these approaches. Using this intelligent spectral signature bio-imaging method, we could discriminate normal and aganglionic colon tissue of the Hirschsprung's disease mouse model with over 95% sensitivity and specificity in various similarity measure methods and various anatomic organs such as parathyroid gland, thyroid gland and pre-tracheal fat in dissected neck of the rat in vivo.

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

    PubMed

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

    2013-02-21

    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

  13. Application Of Micro-Highspeed Flow Visualization In Study Of Blood Cells Rheology In Vivo

    NASA Astrophysics Data System (ADS)

    Gui-shah, Li; Ni, Liang; Yu-ju, Lin; Jian, Zhang; Qiang, Wang

    1990-01-01

    A new experimental method has been developed in study of rheological behaviour of single red blood cell (RBC) in passing through the capillaries in vivo, using the technique of micro-highspeed cinecamera and micro-highspeed video system. It is one of the most important topics in the study of microcirculatory theories that fur-ther understand the deformability of RBC, flow states, velocities and dynamic mechanimi. A micro-highspeed flow visualization system consisted of essential elements: a biological microscope, a highspeed cinecmera with 35 mm film, a highspeed motion analysis system SP2000 (Kodak U.S.A) and a cold-light source etc. We have investigated the rheological parameters of single RBC in vivo in single capillaries which are about 3.3 to 6.9 um in diameters. The RBCs velocities are 0.1 to 0.25 mm/sec, and maximum shear stress on the outside surface of RBC is 13.8 dyn/cml, and maximum extension of RBC is 10.3 um. In aforementioned experiment, the highspeed flow visualization system frequency at 530 frames/sec and 200 frames/sec were used respectively. In addition, the vasomotion of precapillary sphincters have been measured and a complicated coupling phenomena between the RBC and sphincter have also been recorded and analysed. The experiment were performed with intravital hamsters and frogs. The results obtained by this system shown that the method designed by us are an effective tool in the study of rheological behaviour of single RBC in passing through the blood capillaries in vivoz.

  14. A Neutralizing Prolactin Receptor Antibody Whose In Vivo Application Mimics the Phenotype of Female Prolactin Receptor-Deficient Mice.

    PubMed

    Otto, Christiane; Srneflt, Anna; Ljungars, Anne; Wolf, Siegmund; Rohde-Schulz, Beate; Fuchs, Iris; Schkoldow, Jenny; Mattsson, Mikael; Vonk, Richardus; Harrenga, Axel; Freiberg, Christoph

    2015-11-01

    The prolactin receptor (PRLR) has been implicated in a variety of physiological processes (lactation, reproduction) and diseases (breast cancer, autoimmune diseases). Prolactin synthesis in the pituitary and extrapituitary sites is regulated by different promoters. Dopamine receptor agonists such as bromocriptine can only interfere with pituitary prolactin synthesis and thus do not induce a complete blockade of PRLR signaling. Here we describe the identification of a human monoclonal antibody 005-C04 that blocks PRLR-mediated signaling at nanomolar concentrations in vitro. In contrast to a negative control antibody, the neutralizing PRLR antibody 005-C04 inhibits signal transducer and activator of transcription 5 phosphorylation in T47D cells and proliferation of BaF3 cells stably expressing murine or human PRLRs in a dose-dependent manner. In vivo application of this new function-blocking PRLR antibody reflects the phenotype of PRLR-deficient mice. After antibody administration female mice become infertile in a reversible manner. In lactating dams, the antibody induces mammary gland involution and negatively interferes with lactation capacity as evidenced by reduced milk protein expression in mammary glands and impaired litter weight gain. Antibody-mediated blockade of the PRLR in vivo stimulates hair regrowth in female mice. Compared with peptide-derived PRLR antagonists, the PRLR antibody 005-C04 exhibits several advantages such as higher potency, noncompetitive inhibition of PRLR signaling, and a longer half-life, which allows its use as a tool compound also in long-term in vivo studies. Therefore, we suggest that this antibody will help to further our understanding of the role of auto- and paracrine PRLR signaling in health and disease. PMID:26284426

  15. In vivo determination of the diclofenac skin reservoir: comparison between passive, occlusive, and iontophoretic application

    PubMed Central

    Clijsen, Ron; Baeyens, Jean Pierre; Barel, André Odilon; Clarys, Peter

    2015-01-01

    Aim There is scarce information concerning the pharmacodynamic behavior of topical substances used in the physiotherapy setting. The aim of the present study was to estimate the formation and emptying of the diclofenac (DF) skin reservoir after passive, semiocclusive, and electrically assisted applications of DF. Subjects and methods Five different groups of healthy volunteers (ntotal=60, 23 male and 37 female), participated in this study. A 1% DF (Voltaren Emulgel) formulation (12 mg) was applied on the volar forearms on randomized defined circular skin areas of 7 cm2. DF was applied for 20 minutes under three different conditions at the same time. The presence of DF in the skin results in a reduction of the methyl nicotinate (MN) response. To estimate the bioavailability of DF in the skin, MN responses at different times following initial DF application (1.5, 6, 24, 32, 48, 72, 96, and 120 hours) were analyzed. Results At 1.5 hours after the initial DF application, a significant decrease in MN response was detected for the occluded and iontophoretic delivery. Passive application resulted in a decrease of the MN response from 6 hours post-DF application. The inhibition remained up to 32 hours post-DF application for the iontophoretic delivery, 48 hours for the occluded application, and 72 hours for the passive delivery. At 96 and 120 hours post-DF application none of the MN responses was inhibited. Conclusion The formation and emptying of a DF skin reservoir was found to be dependent on the DF-application mode. Penetration-enhanced delivery resulted in a faster emptying of the reservoir. PMID:25709408

  16. 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)

    Kehayias, J. J.

    2001-07-01

    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.

  17. Optically deviated focusing method based high-speed SD-OCT for in vivo retinal clinical applications

    NASA Astrophysics Data System (ADS)

    Wijesinghe, Ruchire Eranga; Park, Kibeom; Kim, Pilun; Oh, Jaeryung; Kim, Seong-Woo; Kim, Kwangtae; Kim, Beop-Min; Jeon, Mansik; Kim, Jeehyun

    2015-11-01

    The aim of this study is to provide accurately focused, high-resolution in vivo human retinal depth images using an optically deviated focusing method with spectral-domain optical coherence tomography (SD-OCT) system. The proposed method was applied to increase the retinal diagnosing speed of patients with various values of retinal distances (i.e., the distance between the crystalline eye lens and the retina). The increased diagnosing speed was facilitated through an optical modification in the OCT sample arm configuration. Moreover, the optical path length matching process was compensated using the proposed optically deviated focusing method. The developed system was mounted on a bench-top cradle to overcome the motion artifacts. Further, we demonstrated the capability of the system by carrying out in vivo retinal imaging experiments. The clinical trials confirmed that the system was effective in diagnosing normal and abnormal retinal layers as several retinal abnormalities were identified using non-averaged single-shot OCT images, which demonstrate the feasibility of the method for clinical applications.

  18. Programmable oligonucleotide probes design and applications for in situ and in vivo RNA imaging in cells

    NASA Astrophysics Data System (ADS)

    Cheglakov, Zoya

    Unequal spreading of mRNA is a frequent experience observed in varied cell lines. The study of cellular processes dynamics and precise localization of mRNAs offers a vital toolbox to target specific proteins in precise cytoplasmic areas and provides a convenient instrument to uncover their mechanisms and functions. Latest methodological innovations have allowed imaging of a single mRNA molecule in situ and in vivo. Today, Fluorescent In Situ Hybridization (FISH) methods allow the studying of mRNA expression and offer a vital toolbox for accurate biological models. Studies enable analysis of the dynamics of an individual mRNA, have uncovered the multiplex RNA transport systems. With all current approaches, a single mRNA tracking in the mammalian cells is still challenging. This thesis describes mRNA detection methods based on programmable fluorophore-labeled DNA structures complimentary to native targets providing an accurate mRNA imaging in mammalian cells. First method represents beta-actin (ACTB) transcripts in situ detection in human cells, the technique strategy is based on programmable DNA probes, amplified by rolling circle amplification (RCA). The method reports precise localization of molecule of interest with an accuracy of a single-cell. Visualization and localization of specific endogenous mRNA molecules in real-time in vivo has the promising to innovate cellular biology studies, medical analysis and to provide a vital toolbox in drugs invention area. Second method described in this thesis represents miR-21 miRNA detection within a single live-cell resolution. The method using fluorophore-labeled short synthetic DNAs probes forming a stem-loop shape and generating Fluorescent Resonance Energy Transfer (FRET) as a result of target-probes hybridization. Catalytic nucleic acid (DNAzymes) probes are cooperative tool for precise detection of different mRNA targets. With assistance of a complementary fluorophore-quencher labeled substrate, the DNAzymes provide a beneficial strategy for simultaneous tracking readily accomplished by multicolor imaging with diverse fluorescent tags. The third method in this thesis will demonstrate the advantage of DNAzymes probes amplification, and offers potential strategy to monitor miRNAs in mammalian live cells.

  19. Temperature dependence of the optoacoustic transformation efficiency in ex vivo tissues for application in monitoring thermal therapies

    NASA Astrophysics Data System (ADS)

    Nikitin, Sergey M.; Khokhlova, Tatiana D.; Pelivanov, Ivan M.

    2012-06-01

    The calibration dependencies of the optoacoustic (OA) transformation efficiency on tissue temperature are obtained for the application in OA temperature monitoring during thermal therapies. Accurate measurement of the OA signal amplitude versus temperature is performed in different ex vivo tissues in the temperature range 25C to 80C. The investigated tissues were selected to represent different structural components: chicken breast (skeletal muscle), porcine lard (fatty tissue), and porcine liver (richly perfused tissue). Backward mode of the OA signal detection and a narrow probe laser beam were used in the experiments to avoid the influence of changes in light scattering with tissue coagulation on the OA signal amplitude. Measurements were performed in heating and cooling regimes. Characteristic behavior of the OA signal amplitude temperature dependences in different temperature ranges were described in terms of changes in different structural components of the tissue samples. The accuracy of temperature reconstruction from the obtained calibration dependencies for the investigated tissue types is evaluated.

  20. Propagation of normal human epithelial cell populations using an in vivo culture system: description and applications

    SciTech Connect

    Klein-Szanto, A.J.P.; Terzaghi, M.; Mirkin, L.D.; Martin, D.; Shiba, M.

    1982-08-01

    A new model using xenotransplanted human epithelia was developed for the study of toxic and carcinogenic effects of chemicals. Epithelial cells from the respiratory tract of 4 male and 3 female premature and full-term fetuses were enzymatically removed and inoculated into deepithelialized rat tracheas. These were sealed at both ends and transplanted subcutaneously into nude mice. After 3 to 4 weeks, a normal mucociliary epithelium covered the tracheal lumen. At this stage the epithelial cells could be isolated again and transplanted into new denuded rat tracheas. This passaging could be repeated up to six times, each permitting an amplification factor of approximately 3. Tracheal transplants containing cells of human origin (in vivo Passages 2 to 4) were treated with 7,120dimethylbenz(a)anthracene. Hyperplasias, squamous metaplasias, and dysplasias were seen 1 to 8 weeks after initiation of treatment, indicating that the responses of human and rodent epithelial cells to polycyclic aromatic hydrocarbons are similar. Initial experiments with skin and esophageal epithelia suggest that other covering epithelia could also be used in this fashion for evaluation of toxicants and carcinogens that are likely to come into contact with these tissues.

  1. Application of a Bioinformatics-Based Approach to Identify Novel Putative in vivo BACE1 Substrates

    PubMed Central

    Johnson, Joseph L; Chambers, Emily; Jayasundera, Keerthi

    2013-01-01

    BACE1, a membrane-bound aspartyl protease that is implicated in Alzheimers disease, is the first protease to cut the amyloid precursor protein resulting in the generation of amyloid-? and its aggregation to form senile plaques, a hallmark feature of the disease. Few other native BACE1 substrates have been identified despite its relatively loose substrate specificity. We report a bioinformatics approach identifying several putative BACE1 substrates. Using our algorithm, we successfully predicted the cleavage sites for 70% of known BACE1 substrates and further validated our algorithm output against substrates identified in a recent BACE1 proteomics study that also showed a 70% success rate. Having validated our approach with known substrates, we report putative cleavage recognition sequences within 962 proteins, which can be explored using in vivo methods. Approximately 900 of these proteins have not been identified or implicated as BACE1 substrates. Gene ontology cluster analysis of the putative substrates identified enrichment in proteins involved in immune system processes and in cell surface protein-protein interactions. PMID:25288897

  2. In-vivo continuous measurement of interstitial pH for intensive care applications

    NASA Astrophysics Data System (ADS)

    Baldini, F.; Ellmerer, M.; Giannetti, A.; Koehler, H.; Mencaglia, A. A.; Pieber, T.

    2007-02-01

    An optical sensor for the continuous detection of pH in the interstitial fluid was developed. The pH sensing layer is immobilised on the internal wall of a glass capillary which is in series with the microdialysis catheter. Phenol red is the pH indicator and is covalently bound directly to the glass surface by means of the Mannich reaction. An optoelectronic unit, which makes use of a light emitting diode at 590 nm as source and a photodiode as detector, is used for the interrogation of the glass capillary. Optical fibres (core diameter: 200 μm) are used to couple the sensing capillary with the unit. Effect of the ionic strength was studied and the performance of the sensor in contact with dialysed blood was carefully investigated. Particular attention was given also to the pH recovery rate, which is given by the ratio between the hydrogen ion concentration in the perfusate and the hydrogen ion concentration in the analysed medium. The pH sensor works in the range 6-8 pH units and it is characterised by an accuracy of 0.07 pH units and a response time of the order of the minute. Long term stability was checked and the sensor is perfectly working for a period of three days, when exposed to dialysed blood. In vivo tests on animals and on volunteers are described.

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

    PubMed Central

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

    2012-01-01

    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

  4. In vivo biochemistry: Applications for small molecule biosensors in plant biology

    PubMed Central

    Jones, Alexander; Grossmann, Guido; Danielson, Jonas Å.H.; Sosso, Davide; Chen, Li-Qing; Ho, Cheng Hsun; Frommer, Wolf B.

    2013-01-01

    Summary Revolutionary new technologies, namely in the areas of DNA sequencing and molecular imaging, continue to impact new discoveries in plant science and beyond. For decades we have been able to determine properties of enzymes, receptors and transporters in vitro or in heterologous systems, and more recently been able to analyze their regulation at the transcriptional level, use GFP reporters to obtain insights into cellular and subcellular localization, and measure ion and metabolite levels with unprecedented precision using mass spectrometry. However, we lack key information on location and dynamics of the substrates of enzymes, receptors and transporters, and on the regulation of these proteins in their cellular environment. Such information can now be obtained by transitioning from in vitro to in vivo biochemistry using biosensors. Genetically encoded fluorescent protein-based sensors for ion and metabolite dynamics provide highly resolved spatial and temporal information, and are complemented by sensors for pH, redox, voltage, and tension. They serve as powerful tools for identifying missing processes (e.g. glucose transport across ER membranes), components (e.g. SWEET sugar transporters for cellular sugar efflux), and signaling networks (e.g. from systematic screening of mutants that affect sugar transport or cytosolic and vacuolar pH). Combined with the knowledge of properties of enzymes and transporters and their interactions with the regulatory machinery, biosensors promise to be key diagnostic tools for systems and synthetic biology. PMID:23587939

  5. In vivo efficacy and bioavailability of lumefantrine: Evaluating the application of Pheroid technology.

    PubMed

    du Plessis, Lissinda H; Govender, Katya; Denti, Paolo; Wiesner, Lubbe

    2015-11-01

    The oral absorption of compounds with low aqueous solubility, such as lumefantrine, is typically limited by the dissolution rate in the gastro-intestinal tract, resulting in erratic absorption and highly variable bioavailability. In previous studies we reported on the ability of Pheroid vesicles to improve the bioavailability of poorly soluble drugs. In the present study a Pro-Pheroid formulation, a modification of the previous formulation, was applied to improve the solubility of lumefantrine after oral administration and compared to lumefantrine in DMSO:water (1:9v/v) solution (reference solution). A bioavailability study of lumefantrine was conducted in a mouse model in fed and fasted states. When using the reference solution, the bioavailability of the lumefantrine heavily depended on food intake, resulting in a 2.7 times higher bioavailability in the fed state when compared to the fasted state. It also showed large between-subject variability. When formulated using Pro-Pheroid, the bioavailability of lumefantrine was 3.5 times higher as compared to lumefantrine in the reference solution and fasting state. Pro-Pheroid also dramatically reduced the effects of food intake and the between-subject variability for bioavailability observed with the reference. In vivo antimalarial efficacy was also evaluated with lumefantrine formulated using Pro-Pheroid technology compared to the reference solution. The results indicated that lumefantrine in Pro-Pheroid formulation exhibited improved antimalarial activity in vitro by 46.8%, when compared to the reference. The results of the Peters' 4-day suppressive test indicated no significant difference in the efficacy or mean survival time of the mice in the Pro-Pheroid formulation and reference test groups when compared to the positive control, chloroquine. These findings suggest that using the Pro-Pheroid formulation improves the bioavailability of lumefantrine, eliminates the food effect associated with lumefantrine as well as significantly reduces the between subject variability in bioavailability when compared to the reference solution. PMID:26478276

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

    PubMed Central

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

    2014-01-01

    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

  7. Simultaneous Determination of 11 Illicit Phenethylamines in Hair by LC-MS-MS: In Vivo Application.

    PubMed

    Nieddu, Maria; Burrai, Lucia; Demontis, Maria Piera; Varoni, Maria Vittoria; Baralla, Elena; Trignano, Claudia; Boatto, Gianpiero

    2015-09-01

    Existing phenethylamines are a class of synthetic compounds that differ from each other only in small changes to a largely conserved chemical structure. The recreational and illicit use of phenethylamines is a widespread problem. A simple procedure for the simultaneous quantitative determination in hair of 11 phenethylamines that are officially recognized as illicit by Italian legislation (p-methoxyamphetamine; p-methoxymethamphetamine; 3,4,5-trimethoxyamphetamine; 2,5-dimethoxyamphetamine; 2,5-dimethoxy-4-methylamphetamine; 2,5-dimethoxy-4-ethylamphetamine; 2,5-dimethoxy-4-bromoamphetamine; 2,5-dimethoxy-4-bromophenethylamine; 2,5-dimethoxy-4-iodophenethylamine; 2,5-dimethoxy-4-ethylthiophenethylamine and 2,5-dimethoxy-4-n-propylthiophenethylamine) has been developed and validated. Extraction from the matrix was performed after incubation in methanolic HCl and filtered reconstituted extracts were injected into a liquid chromatography/tandem mass spectrometry system (LC-MS-MS) without any further purification steps. This validated LC-MS-MS method has been used to determine the in vivo accumulation/retention of the above target analytes in hair after repeat oral administration to rats. This experiment further permitted investigation of the effect of pigmentation on the uptake of these phenethylamines by hair and the effect of hair pigmentation. The developed method could potentially be used for forensic and toxicological purposes, in the detection and quantitation of these illicit substances in human hair in workplace drug testing; drug-facilitated crime investigation; driver re-licensing; determining drug abuse history and postmortem toxicology. PMID:26025163

  8. Fabrication of Large Size Ex Vivo-Produced Oral Mucosal Equivalents for Clinical Application.

    PubMed

    Kato, Hiroko; Marcelo, Cynthia L; Washington, James B; Bingham, Eve L; Feinberg, Stephen E

    2015-09-01

    The soft tissue reconstruction of significant avulsed and/or surgically created tissue defects requires the ability to manufacture substantial soft tissue constructs for repair of the resulting wounds. In this study, we detail the issues that need to be addressed in upsizing the manufacture of larger tissue-engineered devices (ex vivo-produced oral mucosa equivalent [EVPOME]) in vitro from a methodology previously used for smaller constructs. The larger-sized EVPOME, consisting of autologous human oral keratinocytes and a dermal substitute, AlloDerm(®), was fabricated for the purpose of reconstructing large clinical defects. Regulated as an autologous somatic cell therapy product, the fabrication process abided by current Good Manufacturing Practices and current Good Tissue Practices as required by the Center for Biologics Evaluation and Research (CBER) of the United States Food and Drug Administration (FDA). Successful fabrication of large EVPOMEs utilized a higher cell seeding density (5.3×10(5) cells/cm(2)) with a relatively thinner AlloDerm, ranging from 356.6 to 508.0 μm in thickness. During the air-liquid interface culture, the thickness of the scaffold affected the medium diffusion rate, which, in turn, resulted in changes of epithelial stratification. Histologically, keratinocyte progenitor (p63), proliferation (Ki-67), and late differentiation marker (filaggrin) expression showed differences correlating with the expression of glucose transporter-1 (GLUT1) in the EVPOMEs from the thickest (550-1020 μm) to the thinnest (228.6-330.2 μm) AlloDerm scaffold. Glucose consumption and 2-deoxyglucose (2DG) uptake showed direct correlation with scaffold thickness. The scaffold size and thickness have an impact on the cellular phenotype and epithelial maturation in the manufacturing process of the EVPOME due to the glucose accessibility influenced by the diffusion rate. These outcomes provide basic strategies to manufacture a large-sized, healthy EVPOME graft for reconstructing large mucosa defects. PMID:25760802

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

    NASA Astrophysics Data System (ADS)

    Kennedy, Laura Carpin

    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.

  10. Conditional expression of Lodavin, an avidin-tagged LDL receptor, for biotin-mediated applications in vivo.

    PubMed

    Murugan, Subramanian; Saarela, Ulla; Airenne, Kari; Shan, Jingdong; Skovorodkin, Ilya; Yl-Herttuala, Seppo; Vainio, Seppo J

    2012-09-01

    Lodavin represents an engineered fusion protein that consists of a cytoplasmic and a transmembrane domain of the human low-density lipoprotein receptor coupled to an extracellular avidin monomer. Biotinylated compounds have been successfully targeted to Lodavin-expressing cells that have been transduced by a Lodavin-containing virus, and the targeting is based on the high affinity between biotin and avidin. We engineered a Rosa26 (R26R) knock-in Lodavin mouse to develop biotin-based applications such as targeted drug delivery, cell purification, and tissue imaging in vivo. A cDNA encoding Lodavin was inserted downstream of a floxed ?geo resistance gene in the R26R locus in embryonic stem cells, and a germ line-derived R26RLodavin mouse line was generated. Efficient removal of the floxed ?geo cassette and conditional activation of Lodavin expression was achieved as a result of crossing the R26RLodavin mice with HoxB7-Cre, Wnt4-Cre, or Tie1-Cre mice. In summary, the R26RLodavin mouse line may provide a useful tool for testing and developing applications with the aid of avidin and biotin interaction. PMID:22467513

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

    PubMed Central

    2014-01-01

    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

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

    PubMed

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

    2008-05-01

    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

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

    SciTech Connect

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

    2008-05-15

    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.

  14. Sodium-22-radiolabeled silica nanoparticles as new radiotracer for biomedical applications: in vivo positron emission tomography imaging, biodistribution, and biocompatibility

    PubMed Central

    Al Faraj, Achraf; Alotaibi, Basem; Shaik, Abjal Pasha; Shamma, Khaled Z; Al Jammaz, Ibrahim; Gerl, Jrgen

    2015-01-01

    Despite their advantageous chemical properties for nuclear imaging, radioactive sodium-22 (22Na) tracers have been excluded for biomedical applications because of their extremely long lifetime. In the current study, we proposed, for the first time, the use of 22Na radiotracers for pre-clinical applications by efficiently loading with silica nanoparticles (SiNPs) and thus offering a new life for this radiotracer. Crown-ether-conjugated SiNPs (300 nm; ?0.180.1 mV) were successfully loaded with 22Na with a loading efficacy of 98.1%1.4%. Noninvasive positron emission tomography imaging revealed a transient accumulation of 22Na-loaded SiNPs in the liver and to a lower extent in the spleen, kidneys, and lung. However, the signal gradually decreased in a time-dependent manner to become not detectable starting from 2 weeks postinjection. These observations were confirmed ex vivo by quantifying 22Na radioactivity using ?-counter and silicon content using inductively coupled plasma-mass spectrometry in the blood and the different organs of interest. Quantification of Si content in the urine and feces revealed that SiNPs accumulated in the organs were cleared from the body within a period of 2 weeks and completely in 1 month. Biocompatibility evaluations performed during the 1-month follow-up study to assess the possibility of synthesized nanocarriers to induce oxidative stress or DNA damage confirmed their safety for pre-clinical applications. 22Na-loaded nanocarriers can thus provide an innovative diagnostic agent allowing ultra-sensitive positron emission tomography imaging. On the other hand, with its long lifetime, onsite generators or cyclotrons will not be required as 22Na can be easily stored in the nuclear medicine department and be used on-demand. PMID:26504381

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

    NASA Astrophysics Data System (ADS)

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

    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.

  16. In vitro and in vivo degradation evaluation of novel iron-bioceramic composites for bone implant applications.

    PubMed

    Ulum, M F; Arafat, A; Noviana, D; Yusop, A H; Nasution, A K; Abdul Kadir, M R; Hermawan, H

    2014-03-01

    Biodegradable metals such as magnesium, iron and their alloys have been known as potential materials for temporary medical implants. However, most of the studies on biodegradable metals have been focusing on optimizing their mechanical properties and degradation behavior with no emphasis on improving their bioactivity behavior. We therefore investigated the possibility of improving iron biodegradation rate and bioactivity by incorporating various bioactive bioceramics. The iron-based bioceramic (hydroxyapatite, tricalcium phosphate and biphasic calcium phosphate) composites were prepared by mechanical mixing and sintering process. Degradation studies indicated that the addition of bioceramics lowered the corrosion potential of the composites and slightly increased their corrosion rate compared to that of pure iron. In vitro cytotoxicity results showed an increase of cellular activity when rat smooth muscle cells interacted with the degrading composites compared to pure iron. X-ray radiogram analysis showed a consistent degradation progress with that found in vivo and positive tissue response up to 70 days implantation in sheep animal model. Therefore, the iron-based bioceramic composites have the potential to be used for biodegradable bone implant applications. PMID:24433920

  17. Construction of Chinese adult male phantom library and its application in the virtual calibration of in vivo measurement

    NASA Astrophysics Data System (ADS)

    Chen, Yizheng; Qiu, Rui; Li, Chunyan; Wu, Zhen; Li, Junli

    2016-03-01

    In vivo measurement is a main method of internal contamination evaluation, particularly for large numbers of people after a nuclear accident. Before the practical application, it is necessary to obtain the counting efficiency of the detector by calibration. The virtual calibration based on Monte Carlo simulation usually uses the reference human computational phantom, and the morphological difference between the monitored personnel with the calibrated phantom may lead to the deviation of the counting efficiency. Therefore, a phantom library containing a wide range of heights and total body masses is needed. In this study, a Chinese reference adult male polygon surface (CRAM_S) phantom was constructed based on the CRAM voxel phantom, with the organ models adjusted to match the Chinese reference data. CRAMS phantom was then transformed to sitting posture for convenience in practical monitoring. Referring to the mass and height distribution of the Chinese adult male, a phantom library containing 84 phantoms was constructed by deforming the reference surface phantom. Phantoms in the library have 7 different heights ranging from 155 cm to 185 cm, and there are 12 phantoms with different total body masses in each height. As an example of application, organ specific and total counting efficiencies of Ba-133 were calculated using the MCNPX code, with two series of phantoms selected from the library. The influence of morphological variation on the counting efficiency was analyzed. The results show only using the reference phantom in virtual calibration may lead to an error of 68.9% for total counting efficiency. Thus the influence of morphological difference on virtual calibration can be greatly reduced using the phantom library with a wide range of masses and heights instead of a single reference phantom.

  18. Gellan gum injectable hydrogels for cartilage tissue engineering applications: in vitro studies and preliminary in vivo evaluation.

    PubMed

    Oliveira, João T; Santos, Tírcia C; Martins, Luís; Picciochi, Ricardo; Marques, Alexandra P; Castro, António G; Neves, Nuno M; Mano, João F; Reis, Rui L

    2010-01-01

    Gellan gum is a polysaccharide that we have previously proposed for applications in the cartilage tissue engineering field. In this work, gellan gum hydrogels were tested for their ability to be used as injectable systems using simple processing methods, able to deliver and maintain chondrocytes by in situ gelation, and support cell viability and production of extracellular matrix (ECM). Rheological measurements determined that the sol-gel transition occurred near the body temperature at 39 degrees C, upon temperature decrease, in approximately 20 s. Gellan gum discs shows a storage compression modulus of around 80 kPa at a frequency of 1 Hz by dynamic mechanical analysis. Human articular chondrocytes were encapsulated in the gels, cultured in vitro for total periods of 56 days, and analyzed for cell viability and ECM production. Calcein AM staining showed that cell kept viable after 14 days and the histological analysis and real-time quantitative polymerase chain reaction revealed that hyaline-like cartilage ECM was synthesized. Finally, the in vivo performance of the gellan gum hydrogels, in terms of induced inflammatory reaction and integration into the host tissue, was evaluated by subcutaneous implantation in Balb/c mice for 21 days. Histological analysis showed a residual fibrotic capsule at the end of the experiments. Dynamic mechanical analysis revealed that the gels were stable throughout the experiments while evidencing a tendency for decreasing mechanical properties, which was consistent with weight measurements. Altogether, the results demonstrate the adequacy of gellan gum hydrogels processed by simple methods for noninvasive injectable applications toward the formation of a functional cartilage tissue-engineered construct and originally report the preliminary response of a living organism to the subcutaneous implantation of the gellan gum hydrogels. These are the two novel features of this work. PMID:19702512

  19. Construction of Chinese adult male phantom library and its application in the virtual calibration of in vivo measurement.

    PubMed

    Chen, Yizheng; Qiu, Rui; Li, Chunyan; Wu, Zhen; Li, Junli

    2016-03-01

    In vivo measurement is a main method of internal contamination evaluation, particularly for large numbers of people after a nuclear accident. Before the practical application, it is necessary to obtain the counting efficiency of the detector by calibration. The virtual calibration based on Monte Carlo simulation usually uses the reference human computational phantom, and the morphological difference between the monitored personnel with the calibrated phantom may lead to the deviation of the counting efficiency. Therefore, a phantom library containing a wide range of heights and total body masses is needed. In this study, a Chinese reference adult male polygon surface (CRAM_S) phantom was constructed based on the CRAM voxel phantom, with the organ models adjusted to match the Chinese reference data. CRAM_S phantom was then transformed to sitting posture for convenience in practical monitoring. Referring to the mass and height distribution of the Chinese adult male, a phantom library containing 84 phantoms was constructed by deforming the reference surface phantom. Phantoms in the library have 7 different heights ranging from 155 cm to 185 cm, and there are 12 phantoms with different total body masses in each height. As an example of application, organ specific and total counting efficiencies of Ba-133 were calculated using the MCNPX code, with two series of phantoms selected from the library. The influence of morphological variation on the counting efficiency was analyzed. The results show only using the reference phantom in virtual calibration may lead to an error of 68.9% for total counting efficiency. Thus the influence of morphological difference on virtual calibration can be greatly reduced using the phantom library with a wide range of masses and heights instead of a single reference phantom. PMID:26894453

  20. In vivo skin irritation potential of a Castanea sativa (Chestnut) leaf extract, a putative natural antioxidant for topical application.

    PubMed

    Almeida, Isabel F; Valentão, Patrícia; Andrade, Paula B; Seabra, Rosa M; Pereira, Teresa M; Amaral, M Helena; Costa, Paulo C; Bahia, M Fernanda

    2008-11-01

    Topical application of natural antioxidants has proven to be effective in protecting the skin against ultraviolet-mediated oxidative damage and provides a straightforward way to strengthen the endogenous protection system. However, natural products can provoke skin adverse effects, such as allergic and irritant contact dermatitis. Skin irritation potential of Castanea sativa leaf ethanol:water (7:3) extract was investigated by performing an in vivo patch test in 20 volunteers. Before performing the irritation test, the selection of the solvent and extraction method was guided by the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging test and polyphenols extraction (measured by the Folin Ciocalteu assay). Iron-chelating activity and the phenolic composition (high performance liquid chromatography/diode array detection) were evaluated for the extract obtained under optimized conditions. The extraction method adopted consisted in 5 short extractions (10 min.) with ethanol:water (7:3), performed at 40 degrees. The IC(50) found for the iron chelation and DPPH scavenging assays were 132.94 +/- 9.72 and 12.58 +/- 0.54 microg/ml (mean +/- S.E.M.), respectively. The total phenolic content was found to be 283.8 +/- 8.74 mg GAE/g extract (mean +/- S.E.M.). Five phenolic compounds were identified in the extract, namely, chlorogenic acid, ellagic acid, rutin, isoquercitrin and hyperoside. The patch test carried out showed that, with respect to irritant effects, this extract can be regarded as safe for topical application. PMID:18793273

  1. Preparation, characterization, and in vitro testing of poly(lactide-co-glycolide) and dextran magnetic microspheres for in vivo applications

    NASA Astrophysics Data System (ADS)

    Leamy, Patrick J.

    Many research groups are investigating degradable magnetic particles for magnetic resonance imaging (MRI) contrast agents and as carriers for magnetic drug guidance. These particles are composite materials with a degradable polymer matrix and iron oxide nanoparticles for magnetic properties. The degradable polymer matrix acts to provide colloidal stability and, for drug delivery applications, provides a reservoir for the storage and release of drugs. Natural polymers, like albumin and dextran, which degrade by the action of enzymes; have been used for the polymer matrix. Iron oxide nanoparticles are used for magnetic properties since they can be digested in vivo and have low toxicities. Polylactic acid (PLA) and its copolymers with polyglycolic acid (PLGA) are versatile polymers that degrade by simple hydrolysis without the aid of enzymes. Microspheres are easily formed using the solvent extraction/evaporation method and a wide range of drugs can be encapsulated in them. Magnetic PLGA microspheres suitable for applications were synthesized for the first time in this dissertation. This was accomplished by coating iron oxide nanoparticles with oleic acid to make them dispersible in the organic solvents used in the extraction/evaporation microsphere preparation method. In addition to the magnetic PLGA microspheres, a novel all-aqueous method for preparing crosslinked dextran magnetic microspheres was developed in this dissertation. This method uses free radical polymerization for crosslinking and does not require the use of flammable and harmful solvents. For efficient MRI contrast and magnetic drug guidance, maximized iron oxide content of microspheres is desirable. The two different microsphere preparation methods were optimized for iron oxide content. The effect of iron oxide content on microsphere size and morphology was studied. In addition, an in vitro circulation model was used to evaluate the ability of magnetic microspheres to be guided at physiologic blood flow velocities. The MRI contrast effect was studied as a function of microsphere concentration.

  2. Portable semiconductor disk laser for in vivo tissue monitoring: a platform for the development of clinical applications

    NASA Astrophysics Data System (ADS)

    Aviles-Espinosa, Rodrigo; Filippidis, George; Hamilton, Craig; Malcolm, Graeme; Weingarten, Kurt J.; Sdmeyer, Thomas; Barbarin, Yohan; Keller, Ursula; Artigas, David; Loza-Alvarez, Pablo

    2011-07-01

    Long term in vivo observations at large penetration depths and minimum sample disturbance are some of the key factors that have enabled the study of different cellular and tissue mechanisms. The continuous optimization of these aspects is the main driving force for the development of advanced microscopy techniques such as those based on nonlinear effects. Its wide implementation for general biomedical applications is however, limited as the currently used nonlinear microscopes are based on bulky, maintenance-intensive and expensive excitation sources such as Ti:sapphire ultrafast lasers. We present the suitability of a portable (140x240x70 mm) ultrafast semiconductor disk laser (SDL) source, to be used in nonlinear microscopy. The SDL is modelocked by a quantum-dot semiconductor saturable absorber mirror (SESAM). This enables the source to deliver an average output power of 287 mW with 1.5 ps pulses at 500 MHz, corresponding to a peak power of 0.4 kW. The laser center wavelength (965 nm) virtually matches the two-photon absorption cross-section of the widely used Green Fluorescent Protein (GFP). This property greatly relaxes the required peak powers, thus maximizing sample viability. This is demonstrated by presenting two-photon excited fluorescence images of GFP labeled neurons and second-harmonic generation images of pharyngeal muscles in living C. elegans nematodes. Our results also demonstrate that this compact laser is well suited for efficiently exciting different biological dyes. Importantly this non expensive, turn-key, compact laser system could be used as a platform to develop portable nonlinear bio-imaging devices, facilitating its widespread adoption in biomedical applications.

  3. Probe depth matters in dermal microdialysis sampling of benzoic acid after topical application: an ex vivo study in human skin.

    PubMed

    Holmgaard, R; Benfeldt, E; Bangsgaard, N; Sorensen, J A; Brosen, K; Nielsen, F; Nielsen, J B

    2012-01-01

    Microdialysis (MD) in the skin - dermal microdialysis (DMD) - is a unique technique for sampling of topically as well as systemically administered drugs at the site of action, e.g. sampling of dermatological drug concentrations in the dermis. Debate has concerned the existence of a correlation between the depth of the sampling device - the probe - in the dermis and the amount of drug sampled following topical drug administration. This study evaluates the relation between probe depth and drug sampling using dermal DMD sampling ex vivo in human skin. We used superficial (<1 mm), intermediate (1-2 mm) and deep (>2 mm) positioning of the linear MD probe in the dermis of human abdominal skin, followed by topical application of 4 mg/ml of benzoic acid (BA) in skin chambers overlying the probes. Dialysate was sampled every hour for 12 h and analysed for BA content by high-performance liquid chromatography. Probe depth was measured by 20-MHz ultrasound scanning. The area under the time-versus-concentration curve (AUC) describes the drug exposure in the tissue during the experiment and is a relevant parameter to compare for the 3 dermal probe depths investigated. The AUC(0-12) were: superficial probes: 3,335 ± 1,094 μg·h/ml (mean ± SD); intermediate probes: 2,178 ± 1,068 μg·h/ml, and deep probes: 1,159 ± 306 μg·h/ml. AUC(0-12) sampled by the superficial probes was significantly higher than that of samples from the intermediate and deeply positioned probes (p value <0.05). There was a significant inverse correlation between probe depth and AUC(0-12) sampled by the same probe (p value <0.001, r(2) value = 0.5). The mean extrapolated lag-times (±SD) for the superficial probes were 0.8 ± 0.1 h, for the intermediate probes 1.7 ± 0.5 h, and for the deep probes 2.7 ± 0.5 h, which were all significantly different from each other (p value <0.05). In conclusion, this paper demonstrates that there is an inverse relationship between the depth of the probe in the dermis and the amount of drug sampled following topical penetration ex vivo. The result is of relevance to the in vivo situation, and it can be predicted that the differences in sampling at different probe depths will have a more significant impact in the beginning of a study or in studies of short duration. Based on this study it can be recommended that studies of topical drug penetration using DMD sampling should include measurements of probe depth and that efforts should be made to minimize probe depth variability. PMID:21849814

  4. Application of C60 Fullerene-Doxorubicin Complex for Tumor Cell Treatment In Vitro and In Vivo.

    PubMed

    Panchuk, R R; Prylutska, S V; Chumakl, V V; Skorokhyd, N R; Lehka, L V; Evstigneev, M P; Prylutskyy, Yu I; Berger, W; Heffeter, P; Scharff, P; Ritter, U; Stoika, R S

    2015-07-01

    Development of nanocarriers for effective drug delivery to molecular targets in tumor cells is a real problem in modern pharmaceutical chemistry. In the present work we used pristine C60 fullerene as a platform for delivery of anticancer drug doxorubicin (Dox) to its biological targets. The formation of a complex of C60 fullerene with Dox (C60 + Dox) is described and physico-chemical characteristics of such complex are presented. It was found that Dox conjugation with C60 fullerene leads to 1.5-2-fold increase in Dox toxicity towards various human tumor cell lines, compared with such effect when the drug is used alone. Cytotoxic activity of C60 + Dox complex is accompanied by an increased level of cell produced hydrogen peroxide at early time point (3 h) after its addition to cultured cells. At the same time, cellular production of superoxide radicals does not change in comparison with the effect of Dox alone. Cytomorphological studies have demonstrated that C60 + Dox complexes kill tumor cells by apoptosis induction. The results of in vivo experiments using Lewis lung carcinoma in mice confirmed the enhancement of the Dox toxicity towards tumor cells after drug complexation with C60 fullerene. The effect of such complex towards tumor-bearing mice was even more pronounced than that in the in vitro experiment with targeting human tumor cells. The tumor volume decreased by 2.5 times compared with the control, and an average life span of treated animals increased by 63% compared with control. The obtained results suggest a great perspective of application of C60 + Dox complexes for chemotherapy of malignant tumors. PMID:26307837

  5. In vitro and in vivo corrosion properties of new iron-manganese alloys designed for cardiovascular applications.

    PubMed

    Drynda, Andreas; Hassel, Thomas; Bach, Friedrich Wilhelm; Peuster, Matthias

    2015-04-01

    The principle of biodegradation for the production of temporary implant materials (e.g. stents) plays an important role in the treatment of congenital heart defects. In the last decade several attempts have been made with different alloy materials-mainly based on iron and magnesium. None of the currently available materials in this field have demonstrated satisfying results and have therefore not found entry into broad clinical practice. While magnesium or magnesium alloy systems corrode too fast, the corrosion rate of pure iron-stents is too slow for cardiovascular applications. In the last years FeMn alloy systems were developed with the idea that galvanic effects, caused by different electrochemical properties of Fe and Mn, would increase the corrosion rate. In vitro tests with alloys containing up to 30% Mn showed promising results in terms of biocompatibility. This study deals with the development of new FeMn alloy systems with lower Mn concentrations (FeMn 0.5 wt %, FeMn 2.7 wt %, FeMn 6.9 wt %) to avoid Mn toxicity. Our results show, that these alloys exhibit good mechanical features as well as suitable in vitro biocompatibility and corrosion properties. In contrast, the evaluation of these alloys in a mouse model led to unexpected results-even after 9 months no significant corrosion was detectable. Preliminary SEM investigations showed that passivation layers (FeMn phosphates) might be the reason for corrosion resistance. If this can be proved in further experiments, strategies to prevent or dissolve those layers need to be developed to expedite the in vivo corrosion of FeMn alloys. PMID:24976236

  6. Preparation and in vitro/in vivo evaluation of cyclosporin A-loaded nanodecorated ocular implants for subconjunctival application.

    PubMed

    Pehlivan, Sibel Bozdağ; Yavuz, Burçin; Çalamak, Semih; Ulubayram, Kezban; Kaffashi, Abbas; Vural, İmran; Çakmak, Hasan Basri; Durgun, Meltem Ezgi; Denkbaş, Emir Baki; Ünlü, Nurşen

    2015-05-01

    In terms of ocular drug delivery, biodegradable implant systems have several advantages including the ability to provide constant drug concentration at the target site, no necessity for surgical removal, and minimum systemic side effects. Cyclosporin A (CsA) is a neutral, hydrophobic, cyclic peptide of amino acids that frequently used for dry eye disease treatment. The aim of this study was to develop a nanoparticle-loaded implant system for sustained-release CsA delivery following subconjunctival implantation. Poly(lactide-co-glycolide) (85:15) or poly-ε-caprolactone (PCL) were used to prepare two different nanoparticle formulations. These nanoparticles loaded into PCL or poly(lactide-co-caprolactone) implant formulations were prepared by two different methods, which were molding and electrospinning. Size and zeta potential of nanoparticles were determined and the morphology of the formulations were investigated by scanning electron microscopy. CsA-loading efficiencies were calculated and the in vitro degradation and in vitro release studies were performed. MTT test was also performed using L929 fibroblast cells to evaluate the cytotoxicity of the formulations. PCL-PCL-NP-I formulation was implanted to Swiss Albino mice with induced dry eye syndrome to evaluate the efficacy. In vitro release studies showed that the release from the formulations continues between 30 and 60 days, and the cell viability was found to be 77.4%-99.0%. In vivo studies showed that healing is significantly faster in the presence of the selected implant formulation. Results indicated that nanodecorated implants are promising ocular carriers for controlled-release CsA application. PMID:25716582

  7. 4D dosimetry and its applications to pre-treatment quality control and real-time in vivo dosimetry of VMAT treatments

    NASA Astrophysics Data System (ADS)

    Nordstrm, F.; Wetterstedt, S. af; Bck, S. . J.

    2013-06-01

    In this study, a 4D dosimetry concept was developed. This concept included a method for calculation of 3D reference absorbed dose matrices at every control point of the delivery using a clinical treatment planning system (TPS). Further, the gamma evaluation method was extended to incorporate the 4th dimension of the TPS calculated dose distributions. The applications of the 4D dosimetry concept on pre-treatment quality control and real-time in vivo dosimetry were investigated.

  8. Line selection and sensitivity analysis for oxygen sensing in the 1.26-1.27 micron spectral band for the ASCENDS mission

    NASA Astrophysics Data System (ADS)

    Prasad, N.; Browell, E. V.; Zaccheo, T. S.; Karpowicz, B.

    2010-12-01

    The National Research Councils (NRC) Decadal Survey (DS) of Earth Science and Applications from Space has identified the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as an important atmospheric science mission. The CO2 mixing ratio needs to be measured to a precision of 0.5 percent of background or better (slightly less than 2 ppm) at 100-km horizontal resolution overland and 200-km resolution over oceans. To meet this goal, the ASCENDS mission requires simultaneous laser remote sensing of CO2 and O2 in order to convert CO2 column number densities to average column CO2 mixing ratios (XCO2). As such, the CO2 column number density and the O2 column number density will be utilized to derive the average XCO2 column. NASA Langley Research Center, working with its partners, is developing O2 lidar technology in the 1.26-1.27-?m band for surface pressure measurements. To obtain XCO2 with LAS technique the simultaneous measurement of the CO2 column number density, the O2 column number density for converting the CO2 column number density to XCO2 and the total path length of the measurement are required. The O2 LAS operating at 1.26 ?m will be used to convert CO2 number density to mixing ratio. The 1.26-?m spectral band was chosen due to architectural advantage from wavelengths being close to 1.57-?m CO2 LAS column measurements and the favorable spectroscopic characteristics of the O2 absorption line parameters. Furthermore, the surface and atmospheric scattering characteristics from aerosols and thin clouds are nearly the same as for 1.26-?m O2 measurements and the 1.57-?m CO2 measurements. One or more "on-line" wavelengths in the 1.26-?m O2 absorption band have to be carefully chosen to eliminate ambient influences on them when used in conjunction with the integrated path differential absorption (IPDA) technique. The O2 model optical depth calculation is very sensitive to knowledge of the transmitted wavelengths and to the choice of Voigt input parameters. Uncertainties in atmospheric profiles of temperature, pressure and relative humidity can cause ~0.5 % errors in model optical depths. Uncertainties at line center and offset wavelengths of the candidate on-line wavelengths have to be precisely known to reduce uncertainties in O2 concentration measurements from airborne and space based platforms. In this paper, we evaluate systematic relative errors related to uncertainties in O2 absorption line pressure shifts and atmospheric temperature for selected O2 absorption lines suitable for making high precision O2 and XCO2 measurements based on HITRAN database and O2 absorption line measurements.

  9. Laguerre-based method for analysis of time-resolved fluorescence data: application to in-vivo characterization and diagnosis of atherosclerotic lesions

    NASA Astrophysics Data System (ADS)

    Jo, Javier A.; Fang, Qiyin; Papaioannou, Thanassis; Baker, J. Dennis; Dorafshar, Amir; Reil, Todd; Qiao, Jianhua; Fishbein, Michael C.; Freischlag, Julie A.; Marcu, Laura

    2006-03-01

    We report the application of the Laguerre deconvolution technique (LDT) to the analysis of in-vivo time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) data and the diagnosis of atherosclerotic plaques. TR-LIFS measurements were obtained in vivo from normal and atherosclerotic aortas (eight rabbits, 73 areas), and subsequently analyzed using LDT. Spectral and time-resolved features were used to develop four classification algorithms: linear discriminant analysis (LDA), stepwise LDA (SLDA), principal component analysis (PCA), and artificial neural network (ANN). Accurate deconvolution of TR-LIFS in-vivo measurements from normal and atherosclerotic arteries was provided by LDT. The derived Laguerre expansion coefficients reflected changes in the arterial biochemical composition, and provided a means to discriminate lesions rich in macrophages with high sensitivity (>85%) and specificity (>95%). Classification algorithms (SLDA and PCA) using a selected number of features with maximum discriminating power provided the best performance. This study demonstrates the potential of the LDT for in-vivo tissue diagnosis, and specifically for the detection of macrophages infiltration in atherosclerotic lesions, a key marker of plaque vulnerability.

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

    PubMed Central

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

    2015-01-01

    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

  11. A Novel Micro-Linear Vector for In Vitro and In Vivo Gene Delivery and Its Application for EBV Positive Tumors

    PubMed Central

    Zhang, Ge; Ou, Xue-Ling; Yang, Xiang-Ling; Wong, Chris K. C.; Giesy, John P.; Du, Jun; Chen, Shou-Yi

    2012-01-01

    Background The gene delivery vector for DNA-based therapy should ensure its transfection efficiency and safety for clinical application. The Micro-Linear vector (MiLV) was developed to improve the limitations of traditional vectors such as viral vectors and plasmids. Methods The MiLV which contained only the gene expression cassette was amplified by polymerase chain reaction (PCR). Its cytotoxicity, transfection efficiency in vitro and in vivo, duration of expression, pro-inflammatory responses and potential application for Epstein-Barr virus (EBV) positive tumors were evaluated. Results Transfection efficiency for exogenous genes transferred by MiLV was at least comparable with or even greater than their corresponding plasmids in eukaryotic cell lines. MiLV elevated the expression and prolonged the duration of genes in vitro and in vivo when compared with that of the plasmid. The in vivo pro-inflammatory response of MiLV group was lower than that of the plasmid group. The MEKK1 gene transferred by MiLV significantly elevated the sensitivity of B95-8 cells and transplanted tumor to the treatment of Ganciclovir (GCV) and sodium butyrate (NaB). Conclusions The present study provides a safer, more efficient and stable MiLV gene delivery vector than plasmid. These advantages encourage further development and the preferential use of this novel vector type for clinical gene therapy studies. PMID:23077563

  12. Synthesis and in vivo evaluation of the biodistribution of a 18F-labeled conjugate gold-nanoparticle-peptide with potential biomedical application.

    PubMed

    Guerrero, Simon; Herance, José Raul; Rojas, Santiago; Mena, Juan F; Gispert, Juan Domingo; Acosta, Gerardo A; Albericio, Fernando; Kogan, Marcelo J

    2012-03-21

    Gold nanoparticles (AuNPs) have been extensively used in biological applications because of their biocompatibility, size, and ease of characterization, as well as an extensive knowledge of their surface chemistry. These features make AuNPs readily exploitable for biomedical applications, including drug delivery and novel diagnostic and therapeutic approaches. In a previous work, we studied ex vivo distribution of the conjugate C(AuNP)-LPFFD for its potential uses in the treatment of Alzheimer's disease. In this study, we covalently labeled the conjugate with [(18)F]-fluorobenzoate to study the in vivo distribution of the AuNP by positron emission tomography (PET). After intravenous administration in rat, the highest concentration of the radiolabeled conjugate was found in the bladder and urine with a lower proportion in the intestine, demonstrating progressive accumulation compatible with biliary excretion of the conjugate. The conjugate also accumulated in the liver and spleen. PET imaging allowed us to study the in vivo biodistribution of the AuNPs in a noninvasive and sensitive way using a reduced number of animals. Our results show that AuNPs can be covalently and radioactively labeled for PET biodistribution studies. PMID:22284226

  13. Oxygen Sensing Strategies in Mammals and Bacteria

    PubMed Central

    Taabazuing, Cornelius Y.; Hangasky, John A.; Knapp, Michael J.

    2014-01-01

    The ability to sense and adapt to changes in pO2 is crucial for basic metabolism in most organisms, leading to elaborate pathways for sensing hypoxia (low pO2). This review focuses on the mechanisms utilized by mammals and bacteria to sense hypoxia. While responses to acute hypoxia in mammalian tissues lead to altered vascular tension, the molecular mechanism of signal transduction is not well understood. In contrast, chronic hypoxia evokes cellular responses that lead to transcriptional changes mediated by the hypoxia inducible factor (HIF), which is directly controlled by post-translational hydroxylation of HIF by the non-heme Fe(II)/αKG-dependent enzymes FIH and PHD2. Research on PHD2 and FIH is focused on developing inhibitors and understanding the links between HIF binding and the O2 reaction in these enzymes. Sulfur speciation is a putative mechanism for acute O2-sensing, with special focus on the role of H2S. This sulfur-centered model is discussed, as are some of the directions for further refinement of this model. In contrast to mammals, bacterial O2-sensing relies on protein cofactors that either bind O2 or oxidatively decompose. The sensing modality for bacterial O2-sensors is either via altered DNA binding affinity of the sensory protein, or else due to the actions of a two-component signaling cascade. Emerging data suggests that proteins containing a hemerythrin-domain, such as FBXL5, may serve to connect iron sensing to O2-sensing in both bacteria and humans. As specific molecular machinery becomes identified, these hypoxia sensing pathways present therapeutic targets for diseases including ischemia, cancer, or bacterial infection. PMID:24468676

  14. Oxygen sensing in intestinal mucosal inflammation.

    PubMed

    Flck, Katharina; Fandrey, Joachim

    2016-01-01

    Hypoxia is a hallmark of chronically inflamed tissue. Hypoxia develops from vascular dysfunction and increased oxygen consumption by infiltrating leukocytes. With respect to inflammatory bowel disease (IBD), hypoxia is likely to be of particular importance: Impairment of the intestinal barrier during IBD allows anoxia from the lumen of the gut to spread to formerly normoxic tissue. In addition, disturbed perfusion of inflamed tissue and a higher oxygen demand of infiltrating immune cells lead to low oxygen levels in inflamed mucosal tissue. Here, cells become hypoxic and must now adapt to this condition. The hypoxia inducible factor (HIF)-1 complex is a key transcription factor for cellular adaption to low oxygen tension. HIF-1 is a heterodimer formed by two subunits: HIF-? (either HIF-1? or HIF-2?) and HIF-1?. Under normoxic conditions, hydroxylation of the HIF-? subunit by specific oxygen-dependent prolyl hydroxylases (PHDs) leads to ubiquitin proteasome-dependent degradation. Under hypoxic conditions, however, PHD activity is inhibited; thus, HIF-? can translocate into the nucleus, dimerize with HIF-1?, and bind to hypoxia-responsive elements of HIF-1 target genes. So far, most studies have addressed the function of HIF-1? in intestinal epithelial cells and the effect of HIF stabilization by PHD inhibitors in murine models of colitis. Furthermore, the role of HIF-1? in immune cells becomes more and more important as T cells or dendritic cells for which HIF-1 is of critical importance are highly involved in the pathogenesis of IBD. This review will summarize the function of HIF-1? and the therapeutic prospects for targeting the HIF pathway in intestinal mucosal inflammation. PMID:26206140

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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.

  16. 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

    Qian, Chunqi; Masad, Ihssan S.; Rosenberg, Jens T.; Elumalai, Malathy; Brey, William W.; Grant, Samuel C.; Gorkov, Peter L.

    2012-01-01

    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

  17. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  19. Application of Fluorescent Protein Expressing Strains to Evaluation of Anti-Tuberculosis Therapeutic Efficacy In Vitro and In Vivo

    PubMed Central

    Kong, Ying; Yang, Dong; Cirillo, Suat L. G.; Li, Shaoji; Akin, Ali; Francis, Kevin P.; Maloney, Taylor; Cirillo, Jeffrey D.

    2016-01-01

    The slow growth of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), hinders development of new diagnostics, therapeutics and vaccines. Using non-invasive real-time imaging technologies to monitor the disease process in live animals would facilitate TB research in all areas. We developed fluorescent protein (FP) expressing Mycobacterium bovis BCG strains for in vivo imaging, which can be used to track bacterial location, and to quantify bacterial load in live animals. We selected an optimal FP for in vivo imaging, by first cloning six FPs: tdTomato, mCherry, mPlum, mKate, Katushka and mKeima, into mycobacteria under either a mycobacterial Hsp60 or L5 promoter, and compared their fluorescent signals in vitro and in vivo. Fluorescence from each FP-expressing strain was measured with a multimode reader using the optimal excitation and emission wavelengths for the FP. After normalizing bacterial numbers with optical density, the strain expressing L5-tdTomato displayed the highest fluorescence. We used the tdTomato-labeled M. bovis BCG to obtain real-time images of pulmonary infections in living mice and rapidly determined the number of bacteria present. Further comparison between L5-tdTomato and Hsp60-tdTomato revealed that L5-tdTomato carried four-fold more tdTomato gene copies than Hsp60-tdTomato, which eventually led to higher protein expression of tdTomato. Evaluating anti-TB efficacy of rifampicin and isoniazid therapy in vitro and in vivo using the L5-tdTomato strain demonstrated that this strain can be used to identify anti-TB therapeutic efficacy as quickly as 24 h post-treatment. These M. bovis BCG reporter strains represent a valuable new tool for evaluation of therapeutics, vaccines and virulence. PMID:26934495

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

    PubMed Central

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

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    1999-01-01

    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.

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

    PubMed

    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

    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

  3. A Robust Algorithm for Thickness Computation at Low Resolution and Its Application to In Vivo Trabecular Bone CT Imaging

    PubMed Central

    Liu, Yinxiao; Jin, Dakai; Li, Cheng; Janz, Kathleen F.; Burns, Trudy L.; Torner, James C.; Levy, Steven M.; Saha, Punam K.

    2015-01-01

    Adult bone diseases, especially osteoporosis, lead to increased risk of fracture which in turn is associated with substantial morbidity, mortality, and financial costs. Clinically, osteoporosis is defined by low bone mineral density; however, increasing evidence suggests that the microarchitectural quality of trabecular bone (TB) is an important determinant of bone strength and fracture risk. Accurate measures of TB thickness and marrow spacing is of significant interest for early diagnosis of osteoporosis or treatment effects. Here, we present a new robust algorithm for computing TB thickness and marrow spacing at a low resolution achievable in vivo. The method uses a star-line tracing technique that effectively deals with partial voluming effects of in vivo imaging with voxel size comparable to TB thickness. Also, the method avoids the problem of digitization associated with conventional algorithms based on sampling distance transform along skeletons. Accuracy of the method was examined using computer-generated phantom images, while the robustness of the method was evaluated on human ankle specimens in terms of stability across a wide range of voxel sizes, repeat scan reproducibility under in vivo conditions, and correlation between thickness values computed at ex vivo and in vivo imaging resolutions. Also, the sensitivity of the method was examined by evaluating its ability to predict the bone strength of cadaveric specimens. Finally, the method was evaluated in a human study involving 40 healthy young-adult volunteers (age: 1921 years; 20 males and 20 females) and ten athletes (age: 1921 years; six males and four females). Across a wide range of voxel sizes, the new method is significantly more accurate and robust as compared to conventional methods. Both TB thickness and marrow spacing measures computed using the new method demonstrated strong associations (R2 ? [0.83, 0.87]) with bone strength. Also, the TB thickness and marrow spacing measures allowed discrimination between male and female volunteers (p ? [0.01, 0.04]) as well as between athletes and nonathletes (p ? [0.005, 0.03]). PMID:24686226

  4. A robust algorithm for thickness computation at low resolution and its application to in vivo trabecular bone CT imaging.

    PubMed

    Liu, Yinxiao; Jin, Dakai; Li, Cheng; Janz, Kathleen F; Burns, Trudy L; Torner, James C; Levy, Steven M; Saha, Punam K

    2014-07-01

    Adult bone diseases, especially osteoporosis, lead to increased risk of fracture which in turn is associated with substantial morbidity, mortality, and financial costs. Clinically, osteoporosis is defined by low bone mineral density; however, increasing evidence suggests that the microarchitectural quality of trabecular bone (TB) is an important determinant of bone strength and fracture risk. Accurate measures of TB thickness and marrow spacing is of significant interest for early diagnosis of osteoporosis or treatment effects. Here, we present a new robust algorithm for computing TB thickness and marrow spacing at a low resolution achievable in vivo. The method uses a star-line tracing technique that effectively deals with partial voluming effects of in vivo imaging with voxel size comparable to TB thickness. Also, the method avoids the problem of digitization associated with conventional algorithms based on sampling distance transform along skeletons. Accuracy of the method was examined using computer-generated phantom images, while the robustness of the method was evaluated on human ankle specimens in terms of stability across a wide range of voxel sizes, repeat scan reproducibility under in vivo conditions, and correlation between thickness values computed at ex vivo and in vivo imaging resolutions. Also, the sensitivity of the method was examined by evaluating its ability to predict the bone strength of cadaveric specimens. Finally, the method was evaluated in a human study involving 40 healthy young-adult volunteers (age: 19-21 years; 20 males and 20 females) and ten athletes (age: 19-21 years; six males and four females). Across a wide range of voxel sizes, the new method is significantly more accurate and robust as compared to conventional methods. Both TB thickness and marrow spacing measures computed using the new method demonstrated strong associations (R2 ? [0.83, 0.87]) with bone strength. Also, the TB thickness and marrow spacing measures allowed discrimination between male and female volunteers (p ? [0.01, 0.04]) as well as between athletes and nonathletes (p ? [0.005, 0.03]). PMID:24686226

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

    SciTech Connect

    Rah, Jeong-Eun; Oh, Do Hoon; Kim, Jong Won; Kim, Dae-Hyun; Suh, Tae-Suk; Ji, Young Hoon; Shin, Dongho; Lee, Se Byeong; Kim, Dae Yong; Park, Sung Yong

    2012-10-01

    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.

  6. Estimation of Drug Binding to Brain Tissue: Methodology and in Vivo Application of a Distribution Assay in Brain Polar Lipids.

    PubMed

    Belli, Sara; Assmus, Frauke; Wagner, Bjoern; Honer, Michael; Fischer, Holger; Schuler, Franz; Alvarez-Snchez, Rubn

    2015-12-01

    The unbound drug concentration-effect relationship in brain is a key aspect in CNS drug discovery and development. In this work, we describe an in vitro high-throughput distribution assay between an aqueous buffer and a microemulsion of porcine brain polar lipids (BPL). The derived distribution coefficient LogDBPL was applied to the prediction of unbound drug concentrations in brain (Cu,b) and nonspecific binding to brain tissue. The in vivo relevance of the new assay was assessed for a large set of proprietary drug candidates and CNS drugs by (1) comparing observed compound concentrations in rat CSF with Cu,b calculated using the LogDBPL assay in combination with total drug brain concentrations, (2) comparing Cu,b derived from LogDBPL and total drug brain concentrations to Cu,b estimated using in vitro P-glycoprotein efflux ratio data and unbound drug plasma levels, and (3) comparing tissue nonspecific binding data from human brain autoradiography studies for 17 PET tracer candidates to distribution in BPL. In summary, the LogDBPL assay provides a predicted drug fraction unbound in brain tissue that is nearly identical to brain homogenate equilibrium dialysis with an estimation of in vivo Cu,b that is superior to LogD in octanol. LogDBPL complements the approach for predicting Cu,b based on in vitro P-glycoprotein efflux ratio and in vivo unbound plasma concentration and stands as a fast and cost-effective tool for nonspecific brain binding optimization of PET ligand candidates. PMID:26560069

  7. Magnetic resonance imaging of Fe3O4 nanoparticles embedded in living magnetotactic bacteria for potential use as carriers for in vivo applications.

    PubMed

    Felfoul, Ouajdi; Mohammadi, Mahmood; Martel, Sylvain

    2007-01-01

    MC-1 Magnetotactic Bacteria (MTB) are studied for their potential use as bio-carriers for drug delivery. The exploitation of the flagella combined with nanoparticles magnetite or magnetosomes chain embedded in each bacterium and used to change the swimming direction of each MTB through magnetotaxis provide both propulsion and steering in small diameters blood vessels. But for guiding these MTB towards a target, being capable to image these living bacteria in vivo using an existing medical imaging modality is essential. Here, it is shown that the magnetosomes embedded in each MTB can be used to track the displacement of these bacteria using an MRI system. In fact, these magnetosomes disturb the local magnetic field affecting T1 and T2-relaxation times during MRI. MR T1-weighted and T2-weighted images as well as T2-relaxivity of MTB are studied in order to validate the possibility of monitoring MTB drug delivery operations using a clinical MR scanner. This study proves that MTB affect much more the T2-relaxation than T1-relaxation rate and can be though as a negative contrast agent. The signal decay in the T2-weighted images is found to change proportionally to the bacterial concentration. These results show that a bacterial concentration of 2.2x10(7) cells/mL can be detected using a T2-weighted image, which is very encouraging to further investigate the application of MTB for in vivo applications. PMID:18002242

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

    NASA Astrophysics Data System (ADS)

    Sato, Manabu; Nishidate, Izumi

    2014-05-01

    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.

  9. Morphofunctional Merits of an In Vivo Cryotechnique for Living Animal Organs: Challenges of Clinical Applications from Basic Medical Research

    PubMed Central

    Ohno, Shinichi

    2016-01-01

    Recent advances in molecular and genetic techniques have led to establishment of new biomedical fields; however, morphological techniques are still required for a more precise understanding of functioning cells and tissues. Conventional preparation procedures involve a series of chemical fixation, alcohol dehydration, paraffin or epoxy resin embedding, sectioning, and staining steps. In these steps, technical artifacts modify original morphologies of the cells being examined. Furthermore, difficulties are associated with capturing dynamic images in vivo using conventional chemical fixation. Therefore, a quick-freezing (QF) method was introduced for biological specimens in the 20th century. However, specimens have to be resected from living animal organs with blood supply, and their dynamical morphologies have not been investigated in detail using the QF method. In order to overcome these issues, the tissue resection step of organs had to be avoided and samples needed to be frozen under blood circulation. Our in vivo cryotechnique (IVCT) was an original technique to cryofix samples without resecting their tissues. The most significant merit of IVCT is that blood circulation into organs is preserved at the exact moment of freezing, which has been useful for arresting transient physiological processes of cells and tissues and maintaining their components in situ. PMID:27006516

  10. Evaluation of nano-biphasic calcium phosphate ceramics for bone tissue engineering applications: in vitro and preliminary in vivo studies.

    PubMed

    Reddy, Sujatha; Wasnik, Samiksha; Guha, Avijit; Kumar, Jerald Mahesh; Sinha, Arvind; Singh, Shashi

    2013-01-01

    Reconstruction of critical sized bone injuries is a major problem that continues to inspire the design of new materials and grafts. Natural ceramics (hydroxyapatite (HA) coralline HA, or synthetic HA) and ?-tricalcium phosphate (?-TCP) are being explored for use as scaffolds in bone tissue engineering, among several other materials. The present study evaluated the bone forming capacity of nanosize bioceramics synthesized in situ in poly-vinyl alcohol (PVA) with different ratios of HA and ?-TCP; the Ca/P ratio was 1.62 for bioceramic P1, 1.60 for P2 and 1.58 for P3. Further osteogenesis in vitro with mesenchymal stem cells (MSC) acquired from different sources for osteogenesis in vitro and their bone healing properties in vivo were also evaluated. MSC isolated from human placenta, Wharton's jelly from umbilical cord, fetal bone marrow and adipose tissue, cultured in the presence of nanosize bioceramic particles, were monitored for osteogenic differentiation. Placental cells showed the best osteogenic potential of the different MSC studied on the basis of expression of osteogenic markers. Complete regeneration of the damaged region was observed in vivo when MSC derived from placenta were used with nanoceramic (Ca/P ratio 1.58) in the experimental defect created in the femur of Wistar rats. Even small variation in the Ca/P ratio can alter the outcome of tissue constructs. PMID:22286210

  11. Application of Hyperpolarized [1-13C]Lactate for the In Vivo Investigation of Cardiac Metabolism

    PubMed Central

    Mayer, Dirk; Yen, Yi-Fen; Josan, Sonal; Park, Jae Mo; Pfefferbaum, Adolf; Hurd, Ralph E.; Spielman, Daniel M.

    2012-01-01

    In addition to cancer imaging, 13C-MRS of hyperpolarized pyruvate also has demonstrated utility for the investigation of cardiac metabolism and ischemic heart disease. Although no adverse effects have yet been reported for doses commonly used in vivo, high substrate concentrations lead to supraphysiological pyruvate levels that can affect the underlying metabolism and have to be taken into account when interpreting the results. With lactate serving as an important energy source for the heart and with physiological lactate levels one to two orders of magnitude higher than for pyruvate, hyperpolarized lactate could potentially be used as an alternative to pyruvate for probing cardiac metabolism. In this study, hyperpolarized [1-13C]lactate was used to acquire time-resolved spectra from the healthy rat heart in vivo and to measure dichloroacetate (DCA)-modulated changes in flux through pyruvate dehydrogenase (PDH). Both the primary oxidation of lactate to pyruvate and the subsequent conversion of pyruvate to alanine and bicarbonate could reliably be detected. As DCA stimulates the activity of PDH through inhibition of PDH kinase, a more than 2.5-fold increase in bicarbonate-to-substrate ratio was found after administration of DCA similar to the effect when using [1-13C]pyruvate as the substrate. PMID:22278751

  12. In vitro and in vivo characterization and strain safety of Lactobacillus reuteri NCIMB 30253 for probiotic applications.

    PubMed

    Sulemankhil, Imran; Parent, Mathieu; Jones, Mitchell Lawrence; Feng, Zhenqian; Labb, Alain; Prakash, Satya

    2012-06-01

    Lactobacillus reuteri NCIMB 30253 was shown to have potential as a probiotic by reducing the proinflammatory chemokine interleukin-8. Moreover, this strain was evaluated, by in vitro and in vivo techniques, for its safety for human consumption. The identity of the strain was investigated by metabolic profiling and 16S rRNA gene sequencing, and in vitro safety evaluations were performed by molecular and metabolic techniques. Genetic analysis was confirmed by assessing the minimum inhibitory concentration to a panel of antibiotics, showing that the strain was susceptible to 8 antibiotics tested. The ability of the strain to produce potentially harmful by-products and antimicrobial compounds was evaluated, showing that the strain does not produce biogenic amines and does not show bacteriocin activity or reuterin production. A 28-day repeated oral dose study was conducted in normal Sprague-Dawley rats to support the in vivo strain safety. Oral administration of the strain resulted in no changes in general condition and no clinically significant changes to biochemical and haematological markers of safety relative to vehicle control treated animals. This comprehensive assessment of safety of L.reuteri NCIMB 30253 supports the safety of the strain for use as a probiotic. PMID:22642667

  13. Application of Antrodia camphorata Promotes Rat's Wound Healing In Vivo and Facilitates Fibroblast Cell Proliferation In Vitro

    PubMed Central

    Amin, Zahra A.; Ali, Hapipah M.; Alshawsh, Mohammed A.; Darvish, Pouya H.; Abdulla, Mahmood A.

    2015-01-01

    Antrodia camphorata is a parasitic fungus from Taiwan, it has been documented to possess a variety of pharmacological and biological activities. The present study was undertaken to evaluate the potential of Antrodia camphorata ethanol extract to accelerate the rate of wound healing closure and histology of wound area in experimental rats. The safety of Antrodia camphorata was determined in vivo by the acute toxicity test and in vitro by fibroblast cell proliferation assay. The scratch assay was used to evaluate the in vitro wound healing in fibroblast cells and the excision model of wound healing was tested in vivo using four groups of adult Sprague Dawley rats. Our results showed that wound treated with Antrodia camphorata extract and intrasite gel significantly accelerates the rate of wound healing closure than those treated with the vehicle. Wounds dressed with Antrodia camphorata extract showed remarkably less scar width at wound closure and granulation tissue contained less inflammatory cell and more fibroblast compared to wounds treated with the vehicle. Masson's trichrom stain showed granulation tissue containing more collagen and less inflammatory cell in Antrodia camphorata treated wounds. In conclusion, Antrodia camphorata extract significantly enhanced the rate of the wound enclosure in rats and promotes the in vitro healing through fibroblast cell proliferation. PMID:26557855

  14. Application of Antrodia camphorata Promotes Rat's Wound Healing In Vivo and Facilitates Fibroblast Cell Proliferation In Vitro.

    PubMed

    Amin, Zahra A; Ali, Hapipah M; Alshawsh, Mohammed A; Darvish, Pouya H; Abdulla, Mahmood A

    2015-01-01

    Antrodia camphorata is a parasitic fungus from Taiwan, it has been documented to possess a variety of pharmacological and biological activities. The present study was undertaken to evaluate the potential of Antrodia camphorata ethanol extract to accelerate the rate of wound healing closure and histology of wound area in experimental rats. The safety of Antrodia camphorata was determined in vivo by the acute toxicity test and in vitro by fibroblast cell proliferation assay. The scratch assay was used to evaluate the in vitro wound healing in fibroblast cells and the excision model of wound healing was tested in vivo using four groups of adult Sprague Dawley rats. Our results showed that wound treated with Antrodia camphorata extract and intrasite gel significantly accelerates the rate of wound healing closure than those treated with the vehicle. Wounds dressed with Antrodia camphorata extract showed remarkably less scar width at wound closure and granulation tissue contained less inflammatory cell and more fibroblast compared to wounds treated with the vehicle. Masson's trichrom stain showed granulation tissue containing more collagen and less inflammatory cell in Antrodia camphorata treated wounds. In conclusion, Antrodia camphorata extract significantly enhanced the rate of the wound enclosure in rats and promotes the in vitro healing through fibroblast cell proliferation. PMID:26557855

  15. In vivo fluence rate measurements during Foscan-mediated photodynamic therapy of persistent and recurrent nasopharyngeal carcinomas using a dedicated light applicator

    NASA Astrophysics Data System (ADS)

    van Veen, R. L. P.; Nyst, H.; Indrasari, S. R.; Yudharto, M. A.; Robinson, D. J.; Tan, I. B.; Meewis, C.; Peters, R.; Spaniol, Stefan B.; Stewart, Fiona A.; Levendag, P. C.; Sterenborg, Henricus J. C. M.

    2006-07-01

    The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy-induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan absorption.

  16. Adhesive strength of bone-implant interfaces and in-vivo degradation of PHB composites for load-bearing applications.

    PubMed

    Meischel, M; Eichler, J; Martinelli, E; Karr, U; Weigel, J; Schmller, G; Tschegg, E K; Fischerauer, S; Weinberg, A M; Stanzl-Tschegg, S E

    2016-01-01

    Aim of this study was to evaluate the response of bone to novel biodegradable polymeric composite implants in the femora of growing rats. Longitudinal observation of bone reaction at the implant site (BV/TV) as well as resorption of the implanted pins were monitored using in vivo micro-focus computed tomography (CT). After 12, 24 and 36 weeks femora containing the implants were explanted, scanned with high resolution ex vivo CT, and the surface roughness of the implants was measured to conclude on the ingrowth capability for bone tissue. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to observe changes on the surface of Polyhydroxybutyrate (PHB) during degradation and cell ingrowth. Four different composites with zirconium dioxide (ZrO2) and Herafill() were compared. After 36 weeks in vivo, none of the implants did show significant degradation. The PHB composite with ZrO2 and a high percentage (30%) of Herafill as well as the Mg-alloy WZ21 showed the highest values of bone accumulation (increased BV/TV) around the implant. The lowest value was measured in PHB with 3% ZrO2 containing no Herafill. Roughness measurements as well as EDX and SEM imaging could not reveal any changes on the PHB composites? surfaces. Biomechanical parameters, such as the adhesion strength between bone and implant were determined by measuring the shear strength as well as push-out energy of the bone-implant interface. The results showed that improvement of these mechanical properties of the studied PHBs P3Z, P3Z10H and P3Z30H is necessary in order to obtain appropriate load-bearing material. The moduli of elasticity, tensile strength and strain properties of the PHB composites are close to that of bone and thus promising. Compared to clinically used PLGA, PGA and PLA materials, their additional benefit is an unchanged local pH value during degradation, which makes them well tolerated by cells and immune system. They might be used successfully for personalized 3D printed implants or as coatings of rapidly dissolving implants. PMID:26318571

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

    PubMed

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

    2011-12-01

    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

  18. 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)

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

    2014-02-01

    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.

  19. In Vivo Noninvasive Analysis of Human Forearm Muscle Function and Fatigue: Applications to EVA Operations and Training Maneuvers

    NASA Technical Reports Server (NTRS)

    Fotedar, L. K.; Marshburn, T.; Quast, M. J.; Feeback, D. L.

    1999-01-01

    Forearm muscle fatigue is one of the major limiting factors affecting endurance during performance of deep-space extravehicular activity (EVA) by crew members. Magnetic resonance (MR) provides in vivo noninvasive analysis of tissue level metabolism and fluid exchange dynamics in exercised forearm muscles through the monitoring of proton magnetic resonance imaging (MRI) and phosphorus magnetic resonance spectroscopy (P-31-MRS) parameter variations. Using a space glove box and EVA simulation protocols, we conducted a preliminary MRS/MRI study in a small group of human test subjects during submaximal exercise and recovery and following exhaustive exercise. In assessing simulated EVA-related muscle fatigue and function, this pilot study revealed substantial changes in the MR image longitudinal relaxation times (T2) as an indicator of specific muscle activation and proton flux as well as changes in spectral phosphocreatine-to-phosphate (PCr/Pi) levels as a function of tissue bioenergetic potential.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    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.

  1. Application of both a physical theory and statistical procedure in the analyses of an in vivo study of aerosol deposition

    SciTech Connect

    Cheng, K.H.; Swift, D.L.; Yang, Y.H.

    1995-12-01

    Regional deposition of inhaled aerosols in the respiratory tract is a significant factor in assessing the biological effects from exposure to a variety of environmental particles. Understanding the deposition efficiency of inhaled aerosol particles in the nasal and oral airways can help evaluate doses to the extrathoracic region as well as to the lung. Dose extrapolation from laboratory animals to humans has been questioned due to significant physiological and anatomical variations. Although human studies are considered ideal for obtaining in vivo toxicity information important in risk assessment, the number of subjects in the study is often small compared to epidemiological and animal studies. This study measured in vivo the nasal airway dimensions and the extrathoracic deposition of ultrafine aerosols in 10 normal adult males. Variability among individuals was significant. The nasal geometry of each individual was characterized at a resolution of 3 mm using magnetic resonance imaging (MRI) and acoustic rhinometry (AR). The turbulent diffusion theory was used to describe the nonlinear nature of extrathoracic aerosol deposition. To determine what dimensional features of the nasal airway were responsible for the marked differences in particle deposition, the MIXed-effects NonLINear Regression (MIXNLIN) procedure was used to account for the random effort of repeated measurements on the same subject. Using both turbulent diffusion theory and MIXNLIN, the ultrafine particle deposition is correlated with nasal dimensions measured by the surface area, minimum cross-sectional area, and complexity of the airway shape. The combination of MRI and AR is useful for characterizing both detailed nasal dimensions and temporal changes in nasal patency. We conclude that a suitable statistical procedure incorporated with existing physical theories must be used in data analyses for experimental studies of aerosol deposition that involve a relatively small number of human subjects.

  2. Dynamic in vivo imaging of dual-triggered microspheres for sustained release applications: synthesis, characterization and cytotoxicity study.

    PubMed

    Efthimiadou, Eleni K; Tapeinos, Christos; Chatzipavlidis, Alexandros; Boukos, Nikos; Fragogeorgi, Eirini; Palamaris, Lazaros; Loudos, George; Kordas, George

    2014-01-30

    This paper deals with the synthesis, characterization and property evaluation of drug-loaded magnetic microspheres with pH-responsive cross-linked polymer shell. The synthetic procedure consists of 3 steps, of which the first two comprise the synthesis of a poly methyl methacrylate (PMMA) template and the synthesis of a shell by using acrylic acid (AA) and methyl methacrylate (MMA) as monomers, and divinyl benzene (DVB) as cross-linker. The third step of the procedure refers to the formation of magnetic nanoparticles on the microsphere's surface. AA that attaches pH-sensitivity in the microspheres and magnetic nanoparticles in the inner and the outer surface of the microspheres, enhance the efficacy of this intelligent drug delivery system (DDS), which constitutes a promising approach toward cancer therapy. A number of experimental techniques were used to characterize the resulting microspheres. In order to investigate the in vitro controlled release behavior of the synthesized microspheres, we studied the Dox release percentage under different pH conditions and under external magnetic field. Hyperthermia caused by an alternating magnetic field (AFM) is used in order to study the doxorubicin (Dox) release behavior from microspheres with pH functionality. The in vivo fate of these hybrid-microspheres was tracked by labeling them with the ?-emitting radioisotope (99m)Tc after being intravenously injected in normal mice. According to our results, microsphere present a pH depending and a magnetic heating, release behavior. As expected, labeled microspheres were mainly found in the mononuclear phagocyte system (MPS). The highlights of the current research are: (i) to illustrate the advantages of controlled release by combining hyperthermia and pH-sensitivity and (ii) to provide noninvasive, in vivo information on the spatiotemporal biodistribution of these microsphere by dynamic ?-imaging. PMID:24286923

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

    PubMed Central

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

    2012-01-01

    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

  4. Aptamer photoregulation in vivo

    PubMed Central

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

    2014-01-01

    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

  5. 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

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

    2013-04-01

    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

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

    SciTech Connect

    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. Sandoz Research Inst., Berne Dr. Daniel den Hoed Cancer Centre, Rotterdam Sandoz Pharma AG, Basel )

    1991-01-01

    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.

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

    PubMed

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

    2013-09-01

    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 330-760nm. 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

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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

  9. Special conference of the American Association for Cancer Research on molecular imaging in cancer: linking biology, function, and clinical applications in vivo.

    PubMed

    Luker, Gary D

    2002-04-01

    The AACR Special Conference on Molecular Imaging in Cancer: Linking Biology, Function, and Clinical Applications In Vivo, was held January 23-27, 2002, at the Contemporary Hotel, Walt Disney World, Orlando, FL. Co-Chairs David Piwnica-Worms, Patricia Price and Thomas Meade brought together researchers with diverse expertise in molecular biology, gene therapy, chemistry, engineering, pharmacology, and imaging to accelerate progress in developing and applying technologies for imaging specific cellular and molecular signals in living animals and humans. The format of the conference was the presentation of research that focused on basic and translational biology of cancer and current state-of-the-art techniques for molecular imaging in animal models and humans. This report summarizes the special conference on molecular imaging, highlighting the interfaces of molecular biology with animal models, instrumentation, chemistry, and pharmacology that are essential to convert the dreams and promise of molecular imaging into improved understanding, diagnosis, and management of cancer. PMID:11929844

  10. Comparison of a novel adaptive lens with deformable mirrors and its application in high-resolution in-vivo OCT imaging

    NASA Astrophysics Data System (ADS)

    Rizzotto, Luca; Bonora, Stefano; Jian, Yifan; Zhang, Pengfei; Zam, Azhar; Pugh, Edward N.; Mammano, F.; Zawadzki, Robert J.; Sarunic, Marinko V.

    2015-03-01

    We present a novel adaptive lens that can correct high order aberrations, and which has the potential to increase the diffusion of adaptive optics to many new applications by simplifying the integration of a wavefront corrector inside existing systems. The adaptive lens design that we present can correct for Zernike wavefront aberrations up to the 4th order. The adaptive lens performance are compared with the one of a membrane and bimorph deformable mirrors used together in a wide field microscope setup, using a Shack-Hartmann wavefront sensor for closed loop control. The adaptive lens was also integrated with Fourier Domain Optical Coherence Tomography for in-vivo imaging of mouse retinal structures using an image based wavefront sensorless control.

  11. Characterization of soy polysaccharide and its in vitro and in vivo evaluation for application in colon drug delivery.

    PubMed

    Ursekar, B M; Soni, P S; Date, Abhijit A; Nagarsenker, M S

    2012-09-01

    The objective of the present investigation was to establish potential of commercially available soy polysaccharide (Emcosoy) for colon drug delivery. The soy polysaccharide-ethyl cellulose films were fabricated and characterized. The effect of the pectinase enzyme on the tensile strength and surface morphology of the film was evaluated. The permeation of chlorpheniramine maleate (CPM), a model hydrophilic drug from pectinase enzyme treated and untreated films was measured in pH 7.4 buffer. The soy polysaccharide-ethyl cellulose films were also incubated with Lactobacillus sp. culture for a specific duration, and effect on the CPM permeation was evaluated. The CPM capsules were coated with the soy polysaccharide-ethyl cellulose mixture, and Eudragit S100 was applied as a secondary coat. The coated CPM capsules were radiolabelled, and their in vivo transit was evaluated in human volunteers on oral administration. The pectinase enzyme had a significant influence on the tensile strength and surface morphology of the soy polysaccharide-ethyl cellulose films. The permeability of pectinase enzyme-treated and Lactobacillus sp.-treated films was significantly higher than that of untreated films. The CPM capsules were coated with the soy polysaccharide-ethyl cellulose mixture and Eudragit S100 and were successfully radiolabelled by a simple method. Gamma scintigraphic studies in human volunteers showed that the radiolabelled capsules maintained integrity for at least 9 h after oral administration. Thus, the soy polysaccharide has a potential in colon drug delivery. PMID:22739785

  12. Evaluating the in vitro and in vivo efficacy of nano-structured polymers for bladder tissue replacement applications.

    PubMed

    Pattison, Megan; Webster, Thomas J; Leslie, Jeffrey; Kaefer, Martin; Haberstroh, Karen M

    2007-05-10

    Bladder cancers requiring radical cystectomy, along with congenital and acquired disorders which result in obstruction of the bladder, necessitate surgical measures (including augmentation); such diagnoses bring a clinical need for effective bladder replacement implant designs. Many recent approaches for the design of soft tissue replacement materials have relied on the use of synthetic polymeric substances; unfortunately, the optimal soft tissue implant material is yet to be found. This may, in part, be because current polymeric formulations fail to sufficiently biomimic the neighboring bladder tissue. This study took a brand new approach in designing the next generation of tissue-engineered bladder constructs through the use of nanotechnology, or materials with nanometer (less than 100 nm) surface features. Results provided evidence that nano-structured polymeric scaffolds (specifically, PLGA and PU) created using chemical etching techniques are capable of enhancing the human bladder smooth muscle cell adhesion, proliferation, and the production of extracellular matrix (ECM) proteins. Preliminary in vivo results also speak to the usefulness of such nano-structured materials. In combination, these findings suggest that nano-dimensional PLGA and PU scaffolds are promising replacement materials for the human bladder wall. PMID:17477448

  13. In vivo validation of the design rules of the coronary arteries and their application in the assessment of diffuse disease

    NASA Astrophysics Data System (ADS)

    Zhou, Yifang; Kassab, Ghassan S.; Molloi, Sabee

    2002-03-01

    The conventional rationale that uses per cent diameter reduction to assess diffuse coronary artery disease is not appropriate because no normal reference segments exist. In a recent publication, we have proposed a theoretical model based on physical principles that relate the various morphological and haemodynamic parameters (cross-sectional area, length, volume and flow) of the normal coronary arterial tree. The model was validated using haemodynamic simulations based on detailed morphological data of the pig coronary arterial tree. This paper extends the model validation to in vivo swine studies. Coronary arteriography was performed in five swine (15-18 kg body weight) after power injection of contrast material into the coronary artery. Coronary arterial length was obtained using a 3D reconstruction technique. The arterial volume, cross-sectional area and blood flow were measured using videodensitometry. The proposed relationships between these quantities were validated. Furthermore, a sensitivity analysis was demonstrated based on a simulation of diffuse coronary artery disease (approximately 40% reduction in cross-sectional area). The results of a sensitivity analysis based on a simulation of diffuse coronary artery disease suggest that the relationships between arterial volume, cross-sectional area, blood flow and the distal arterial length can be utilized to quantify moderate levels of diffuse coronary artery disease.

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

    PubMed

    Mudgil, Meetali; Pawar, Pravin K

    2013-06-01

    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

  15. In Vivo Application of Tissue-Engineered Veins Using Autologous Peripheral Whole Blood: A Proof of Concept Study

    PubMed Central

    Olausson, Michael; Kuna, Vijay Kumar; Travnikova, Galyna; Bäckdahl, Henrik; Patil, Pradeep B.; Saalman, Robert; Borg, Helena; Jeppsson, Anders; Sumitran-Holgersson, Suchitra

    2014-01-01

    Vascular diseases are increasing health problems affecting > 25 million individuals in westernized societies. Such patients could benefit from transplantation of tissue-engineered vascular grafts using autologous cells. One challenge that has limited this development is the need for cell isolation, and risks associated with ex vivo expanded stem cells. Here we demonstrate a novel approach to generate transplantable vascular grafts using decellularized allogeneic vascular scaffolds, repopulated with peripheral whole blood (PWB) in vitro in a bioreactor. Circulating, VEGFR-2 +/CD45 + and a smaller fraction of VEGFR-2 +/CD14 + cells contributed to repopulation of the graft. SEM micrographs showed flat cells on the luminal surface of the grafts consistent with endothelial cells. For clinical validation, two autologous PWB tissue-engineered vein conduits were prepared and successfully used for by-pass procedures in two pediatric patients. These results provide a proof of principle for the generation of transplantable vascular grafts using a simple autologous blood sample, making it clinically feasible globally. PMID:26137509

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

    PubMed Central

    Mudgil, Meetali; Pawar, Pravin K.

    2013-01-01

    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 164490 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

  17. In Vivo Osseointegration Performance of Titanium Dioxide Coating Modified Polyetheretherketone Using Arc Ion Plating for Spinal Implant Application

    PubMed Central

    Tsou, Hsi-Kai; Chi, Meng-Hui; Hung, Yi-Wen; Chung, Chi-Jen; He, Ju-Liang

    2015-01-01

    Polyetheretherketone (PEEK), which has biomechanical performance similar to that of human cancellous bone, is used widely as a spinal implant material. However, its bioinertness and hydrophobic surface properties result in poor osseointegration. This study applies a novel modification method, arc ion plating (AIP), that produces a highly osteoblast compatible titanium dioxide (TiO2) coatings on a PEEK substrate. This PEEK with TiO2 coating (TiO2/PEEK) was implanted into the femurs of New Zealand white male rabbits to evaluate its in vivo performance by the push-out test and histological observation. Analytical results show that AIP can prepare TiO2 coatings on bullet-shaped PEEK substrates as implant materials. After prolonged implantation in rabbits, no signs of inflammation existed. Newly regenerated bone formed more prominently with the TiO2/PEEK implant by histological observation. The shear strength of the bone/implant interface increases as implantation period increases. Most importantly, bone bonding performance of the TiO2/PEEK implant was superior to that of bare PEEK. The rutile-TiO2 coatings achieved better osseointegration than the anatase-TiO2 coatings. Therefore, AIP-TiO2 can serve as a novel surface modification method on PEEK for spinal interbody fusion cages. PMID:26504800

  18. Fluorescent Leishmania species: development of stable GFP expression and its application for in vitro and in vivo studies.

    PubMed

    Bolhassani, Azam; Taheri, Tahereh; Taslimi, Yasaman; Zamanilui, Soheila; Zahedifard, Farnaz; Seyed, Negar; Torkashvand, Fatemeh; Vaziri, Behrouz; Rafati, Sima

    2011-03-01

    Reporter genes have proved to be an excellent tool for studying disease progression. Recently, the green fluorescent protein (GFP) ability to quantitatively monitor gene expression has been demonstrated in different organisms. This report describes the use of Leishmania tarentolae (L. tarentolae) expression system (LEXSY) for high and stable levels of GFP production in different Leishmania species including L. tarentolae, L. major and L. infantum. The DNA expression cassette (pLEXSY-EGFP) was integrated into the chromosomal ssu locus of Leishmania strains through homologous recombination. Fluorescent microscopic image showed that GFP transgenes can be abundantly and stably expressed in promastigote and amastigote stages of parasites. Furthermore, flow cytometry analysis indicated a clear quantitative distinction between wild type and transgenic Leishmania strains at both promastigote and amastigote forms. Our data showed that the footpad lesions with GFP-transfected L. major are progressive over time by using fluorescence small-animal imaging system. Consequently, the utilization of stable GFP-transfected Leishmania species will be appropriate for in vitro and in vivo screening of anti-leishmanial drugs and vaccine development as well as understanding the biology of the host-parasite interactions at the cellular level. PMID:21187086

  19. In Vivo Osseointegration Performance of Titanium Dioxide Coating Modified Polyetheretherketone Using Arc Ion Plating for Spinal Implant Application.

    PubMed

    Tsou, Hsi-Kai; Chi, Meng-Hui; Hung, Yi-Wen; Chung, Chi-Jen; He, Ju-Liang

    2015-01-01

    Polyetheretherketone (PEEK), which has biomechanical performance similar to that of human cancellous bone, is used widely as a spinal implant material. However, its bioinertness and hydrophobic surface properties result in poor osseointegration. This study applies a novel modification method, arc ion plating (AIP), that produces a highly osteoblast compatible titanium dioxide (TiO2) coatings on a PEEK substrate. This PEEK with TiO2 coating (TiO2/PEEK) was implanted into the femurs of New Zealand white male rabbits to evaluate its in vivo performance by the push-out test and histological observation. Analytical results show that AIP can prepare TiO2 coatings on bullet-shaped PEEK substrates as implant materials. After prolonged implantation in rabbits, no signs of inflammation existed. Newly regenerated bone formed more prominently with the TiO2/PEEK implant by histological observation. The shear strength of the bone/implant interface increases as implantation period increases. Most importantly, bone bonding performance of the TiO2/PEEK implant was superior to that of bare PEEK. The rutile-TiO2 coatings achieved better osseointegration than the anatase-TiO2 coatings. Therefore, AIP-TiO2 can serve as a novel surface modification method on PEEK for spinal interbody fusion cages. PMID:26504800

  20. High-resolution quantitative whole-breast ultrasound: in vivo application using frequency-domain waveform tomography

    NASA Astrophysics Data System (ADS)

    Sandhu, Gursharan Y. S.; Li, Cuiping; Roy, Olivier; Schmidt, Steven; Duric, Neb

    2015-03-01

    Ultrasound tomography is a promising modality for breast imaging. Many current ultrasound tomography imaging algorithms are based on ray theory and assume a homogeneous background which is inaccurate for complex heterogeneous regions. They fail when the size of lesions approaches the wavelength of ultrasound used. Therefore, to accurately image small lesions, wave theory must be used in ultrasound imaging algorithms to properly handle the heterogeneous nature of breast tissue and the diffraction effects that it induces. Using frequency-domain ultrasound waveform tomography, we present sound speed reconstructions of both a tissue-mimicking breast phantom and in vivo data sets. Significant improvements in contrast and resolution are made upon the previous ray based methods. Where it might have been difficult to differentiate a high sound speed tumor from bulk breast parenchyma using ray based methods, waveform tomography improves the shape and margins of a tumor to help more accurately differentiate it from the bulk breast tissue. Waveform tomography sound speed imaging might improve the ability of finding lesions in very dense tissues, a difficult environment for mammography. By comparing the sound speed images produced by waveform tomography to MRI, we see that the complex structures in waveform tomography are consistent with those in MRI. The robustness of the method is established by reconstructing data acquired by two different ultrasound tomography prototypes.

  1. Topical application of bleaching phenols; in-vivo studies and mechanism of action relevant to melanoma treatment.

    PubMed

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

    2011-04-01

    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 such as 4-tertiary butyl phenol (4-TBP) or monobenzyl ether of hydroquinone (MBEH) showed a significant increase in the migration of Langerhans cells toward the dermis only upon treatment with MBEH, 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 was not observed upon treatment with 4-TBP. Cytokine expression patterns in skin treated with MBEH 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

  2. In Vivo Application of Tissue-Engineered Veins Using Autologous Peripheral Whole Blood: A Proof of Concept Study.

    PubMed

    Olausson, Michael; Kuna, Vijay Kumar; Travnikova, Galyna; Bckdahl, Henrik; Patil, Pradeep B; Saalman, Robert; Borg, Helena; Jeppsson, Anders; Sumitran-Holgersson, Suchitra

    2014-11-01

    Vascular diseases are increasing health problems affecting >25million individuals in westernized societies. Such patients could benefit from transplantation of tissue-engineered vascular grafts using autologous cells. One challenge that has limited this development is the need for cell isolation, and risks associated with ex vivo expanded stem cells. Here we demonstrate a novel approach to generate transplantable vascular grafts using decellularized allogeneic vascular scaffolds, repopulated with peripheral whole blood (PWB) in vitro in a bioreactor. Circulating, VEGFR-2+/CD45+ and a smaller fraction of VEGFR-2+/CD14+ cells contributed to repopulation of the graft. SEM micrographs showed flat cells on the luminal surface of the grafts consistent with endothelial cells. For clinical validation, two autologous PWB tissue-engineered vein conduits were prepared and successfully used for by-pass procedures in two pediatric patients. These results provide a proof of principle for the generation of transplantable vascular grafts using a simple autologous blood sample, making it clinically feasible globally. PMID:26137509

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

    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.

  4. In vivo application of beta amyloid oligomers: a simple tool to evaluate mechanisms of action and new therapeutic approaches.

    PubMed

    Balducci, Claudia; Forloni, Gianluigi

    2014-01-01

    Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cerebral accumulation of extracellular amyloid β (Aβ) and neurofibrillary tangles made of hyperphosphorylated tau protein, two main lesions which appear sequentially during the disease progression. In the last decade numerous studies have proposed small soluble aggregates of Aβ, known as oligomers, as the species responsible for synaptic dysfunction, memory loss and neurodegeneration typical of AD. In vitro and in vivo experiments have identified Aβ oligomers as the elements that can alter synaptic function by a reversible mechanism, which gradually becomes permanent when exposure is continuous. Here we show that intracerebroventricular (ICV) injection in mice of a solution containing specifically Aβ1-42 oligomers substantially affects their memory when tested in the novel object recognition task. This acute mouse model enabled us to distinguish whether oligomers were affecting specific phases of the memory processing. A single injection of Aβ1-42 oligomers before memory consolidation abolished information processing, leading to memory impairment, whereas no such effects were observed when the injection was done once the information had been processed, indicating that the oligomers affect memory consolidation rather than retrieval. Beside Aβ1-42, Aβ1-40 oligomers also impaired memory, and both isoforms were antagonized by the anti-Aβ4G8 monoclonal antibody. This simple and reliable paradigm is useful to investigate the mechanisms through which Aβ oligomers interfere with neuronal processes and to test the efficacy of new therapeutic approaches specifically against these species. We tested several molecules by direct coincubation with Aβ oligomers, ICV injections preceding Aβ oligomers, and the systemic treatment with drugs that cross the blood brain barrier. We also examined the proposed involvement of cellular prion protein as a mediator of the oligomer-induced memory impairment. PMID:23859553

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

    SciTech Connect

    Min, Chul Hee; Zhu, Xuping; Winey, Brian A.; Grogg, Kira; Testa, Mauro; El Fakhri, Georges; Bortfeld, Thomas R.; Paganetti, Harald; Shih, Helen A.

    2013-05-01

    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.

  6. Controlled feeding trials with ungulates: a new application of in vivo dental molding to assess the abrasive factors of microwear.

    PubMed

    Hoffman, Jonathan M; Fraser, Danielle; Clementz, Mark T

    2015-05-15

    Microwear, the quantification of microscopic scratches and pits on the occlusal surfaces of tooth enamel, is commonly used as a paleodietary proxy. For ungulates (hoofed mammals), scratch-dominant microwear distinguishes modern grazers from browsers, presumably as a result of abrasion from grass phytoliths (biogenic silica). However, it is also likely that exogenous grit (i.e. soil, dust) is a contributing factor to these scratch-dominant patterns, which may reflect soil ingestion that varies with feeding height and/or environmental conditions (e.g. dust production in open and/or arid habitats). This study assessed the contribution of exogenous grit to tooth wear by measuring the effects of fine- and medium-grained silica sand on tooth enamel using a novel live-animal tooth-molding technique. It therefore constitutes the first controlled feeding experiment using ungulates and the first in vivo experiment using abrasives of different sizes. Four sheep were fed three diet treatments: (1) a mixture of Garrison and Brome hay (control), (2) hay treated with fine-grained silica sand (180-250 µm) and (3) hay treated with medium-grained silica sand (250-425 µm). We found a significant increase in pit features that was correlated with an increase in grain size of grit, corroborating earlier chewing simulation experiments that produced pits through grit-induced abrasion (i.e. the 'grit effect'). Our results support an interpretation of large silica grains fracturing to create smaller, more abundant angular particles capable of abrasion, with jaw movement defining feature shape (i.e. scratch or pit). PMID:25852070

  7. Metabolism of nitrosamines in vivo IV. Isolation of 3-hydroxy-1-nitrosopyrrolidine from rat urine after application of 1-nitrosopyrrolidine.

    PubMed

    Krger, F W; Bertram, B

    1975-01-01

    After i. p. application of 6 mg/30 muCi/kg 2,5- and 3,4--14C-nitrosopyrrolidine about 20% of the radioactivity is exhaled as 14-CO2 and about 7% is found in the urine. One of the urinary metabolites was identified by thin layer chromatography, combined GC/MS spectrometry and ultraviolet absorption as 3-hydroxy-1-nitrosopyrrolidine. PMID:125015

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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% Youngs 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 Youngs modulus (r = 0.66-0.87, p < 0.05). Similarly, trabecular vBMD and BV/TV of the femur and tibia were clearly related to Youngs 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.

  9. Application of Wnt Pathway Inhibitor Delivering Scaffold for Inhibiting Fibrosis in Urethra Strictures: In Vitro and in Vivo Study

    PubMed Central

    Zhang, Kaile; Guo, Xuran; Zhao, Weixin; Niu, Guoguang; Mo, Xiumei; Fu, Qiang

    2015-01-01

    Objective: To evaluate the mechanical property and biocompatibility of the Wnt pathway inhibitor (ICG-001) delivering collagen/poly(l-lactide-co-caprolactone) (P(LLA-CL)) scaffold for urethroplasty, and also the feasibility of inhibiting the extracellular matrix (ECM) expression in vitro and in vivo. Methods: ICG-001 (1 mg (2 mM)) was loaded into a (P(LLA-CL)) scaffold with the co-axial electrospinning technique. The characteristics of the mechanical property and drug release fashion of scaffolds were tested with a mechanical testing machine (Instron) and high-performance liquid chromatography (HPLC). Rabbit bladder epithelial cells and the dermal fibroblasts were isolated by enzymatic digestion method. (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay) and scanning electron microscopy (SEM) were used to evaluate the viability and proliferation of the cells on the scaffolds. Fibrolasts treated with TGF-β1 and ICG-001 released medium from scaffolds were used to evaluate the anti-fibrosis effect through immunofluorescence, real time PCR and western blot. Urethrography and histology were used to evaluate the efficacy of urethral implantation. Results: The scaffold delivering ICG-001 was fabricated, the fiber diameter and mechanical strength of scaffolds with inhibitor were comparable with the non-drug scaffold. The SEM and MTT assay showed no toxic effect of ICG-001 to the proliferation of epithelial cells on the collagen/P(LLA-CL) scaffold with ICG-001. After treatment with culture medium released from the drug-delivering scaffold, the expression of Collagen type 1, 3 and fibronectin of fibroblasts could be inhibited significantly at the mRNA and protein levels. In the results of urethrography, urethral strictures and fistulas were found in the rabbits treated with non-ICG-001 delivering scaffolds, but all the rabbits treated with ICG-001-delivering scaffolds showed wide caliber in urethras. Histology results showed less collagen but more smooth muscle and thicker epithelium in urethras repaired with ICG-001 delivering scaffolds. Conclusion: After loading with the Wnt signal pathway inhibitor ICG-001, the Collagen/P(LLA-CL) scaffold could facilitate a decrease in the ECM deposition of fibroblasts. The ICG-001 delivering Collagen/P(LLA-CL) nanofibrous scaffold seeded with epithelial cells has the potential to be a promising substitute material for urethroplasty. Longer follow-up study in larger animals is needed in the future. PMID:26610467

  10. Temperature monitoring and lesion volume estimation during double-applicator laser-induced thermotherapy in ex vivo swine pancreas: a preliminary study.

    PubMed

    Saccomandi, Paola; Schena, Emiliano; Giurazza, Francesco; Del Vescovo, Riccardo; Caponero, Michele A; Mortato, Luca; Panzera, Francesco; Cazzato, Roberto L; Grasso, Francesco R; Di Matteo, Francesco M; Silvestri, Sergio; Zobel, Bruno B

    2014-03-01

    Tissue temperature distribution plays a crucial role in the outcome of laser-induced thermotherapy (LITT), a technique employed for neoplasias removal. Since recent studies proposed LITT for pancreatic tumors treatment, assessment of temperature and of its effects around the laser applicator could be useful to define optimal laser settings. The aims of this work are temperature monitoring and measurement of ablated tissue volume in an ex vivo porcine pancreas undergoing double-applicator LITT. A three-dimensional numerical model is implemented to predict temperature rise and volumes of ablated tissue in treated pancreas. Experiments are performed to validate the model, with two modalities: (1) 12-fiber Bragg grating sensors are adopted to monitor the heating and cooling during LITT at several distances from the applicators tip, and (2) 1.5-T MR imaging is used to estimate the ablated volume. Experimental data agree with theoretical ones: at 2mm from both applicators tips, the maximum temperature increase is approximately 60C downward from the tips, while it increases of about 40C and 30C, respectively, at the level and upward from the tips. This behavior occurs also at other distances, proving that the tissue downward from the tip is mostly heated. Furthermore, the estimated volume with MRI agrees with theoretical one (i.d., 0.91??0.09 vs. 0.95cm(3)). The encouraging results indicate that the model could be a suitable tool to choose the optimal laser settings, in order to control the volume of ablated tissue. PMID:23780709

  11. Comparison of doses to the rectum derived from treatment planning system with in-vivo dose values in vaginal vault brachytherapy using cylinder applicators

    PubMed Central

    Obed, Rachel Ibhade; Akinlade, Bidemi Idayat; Ntekim, Atara

    2015-01-01

    Purpose In-vivo measurements to determine doses to organs-at-risk can be an essential part of brachytherapy quality assurance (QA). This study compares calculated doses to the rectum with measured dose values as a means of QA in vaginal vault brachytherapy using cylinder applicators. Material and methods At the Department of Radiotherapy, University College Hospital (UCH), Ibadan, Nigeria, intracavitary brachytherapy (ICBT) was delivered by a GyneSource high-dose-rate (HDR) unit with 60Co. Standard 2D treatment plans were created with HDR basic 2.6 software for prescription doses 5-7 Gy at points 5 mm away from the posterior surface of vaginal cylinder applicators (20, 25, and 30 mm diameters). The LiF:Mg, Ti thermoluminescent dosimeter rods (1 x 6 mm) were irradiated to a dose of 7 Gy on Theratron 60Co machine for calibration purpose prior to clinical use. Measurements in each of 34 insertions involving fourteen patients were performed with 5 TLD-100 rods placed along a re-usable rectal marker positioned in the rectum. The dosimeters were read in Harshaw 3500 TLD reader and compared with doses derived from the treatment planning system (TPS) at 1 cm away from the dose prescription points. Results The mean calculated and measured doses ranged from 2.1-3.8 Gy and 1.2-5.6 Gy with averages of 3.0 ± 0.5 Gy and 3.1 ± 1.1 Gy, respectively, for treatment lengths 2-8 cm along the cylinder-applicators. The mean values correspond to 48.9% and 50.8% of the prescribed doses, respectively. The deviations of the mean in-vivo doses from the TPS values ranged from –1.9 to 2.1 Gy with a p-value of 0.427. Conclusions This study was part of efforts to verify rectal dose obtained from the TPS during vaginal vault brachytherapy. There was no significant difference in the dose to the rectum from the two methods of measurements. PMID:26816506

  12. In vitro and preliminary in vivo toxicity screening of high-surface-area TiO2-chondroitin-4-sulfate nanocomposites for bone regeneration application.

    PubMed

    Kandiah, Kavitha; Venkatachalam, Rajendran; Wang, Chunyan; Valiyaveettil, Suresh; Ganesan, Kumaresan

    2015-04-01

    The goal of this study was to prepare nontoxic, biomimetic TiO2/chondroitin-4-sulfate nanocomposites with osteointegration ability for biomedical applications. Nanocomposites with higher surface area were subjected to bioactivity study and obtained bone-like layer with stoichiometric Ca/P ratio of 1.64 and 1.66. The susceptibility of nanocomposites against Staphylococcus aureus (?16 mm) and Escherichia coli (?12 mm) is favorable in preventing the risk of bone diseases and postoperative infections. Adequate swelling and degradations properties were favorably achieved to reduce the risk of nanoparticle accumulation in cell organelles. Moreover, the toxicity in AGS cell line and biocompatibility in osteoblast-like MG-63 cell line showed no significant mitochondrial damage. In addition, the in vitro expression of osteoblast inducing genes (OCN, OPN, ALP and COL 1) and their up-regulation, and 20% of increased hatching rate in preliminary in vivo (zebrafish) analysis were favorable for the nanocomposite at the ratio of 2:0.50 than pure TiO2. Hence, it can be concluded that among the prepared nanocomposites TCs.5 is a promising biomimetic biomaterial that can be used for advanced orthopedic research and other applications. PMID:25752961

  13. In vitro and in vivo application of pH-sensitive colon-targeting polysaccharide hydrogel used for ulcerative colitis therapy.

    PubMed

    You, Yu Cui; Dong, Ling Ya; Dong, Kai; Xu, Wei; Yan, Yan; Zhang, Lu; Wang, Ke; Xing, Feng Jian

    2015-10-01

    The aim of this study was to prepare, characterize novel types of pH-sensitive konjac gum-xanthan gum-glycerol-sodium alginate hydrogel (KGM-XG-GLY-SA hydrogel) allowing for the site-specific delivering of drugs to the colon and evaluate its colon-targeting characteristic. In this study, hydrophilic drug of hydrocortisone sodium succinate (HSS) was chosen as a model drug and successfully loaded in hydrogel without any organic solvent. In vitro investigations were carried out to evaluate its release process. The drug-loaded hydrogel shown good sustained release property that drugs release from test hydrogel was minimal at pH 1.2 (2h, 23.40%), pH 6.8 (4h, 25.88%), and significantly higher (4h, 70.20%) at pH 7.4. It is clear that adding glycerol in hydrogel as hysteresis preparation prevented the rapid dissolution of material in the higher pH of the intestine. Thus ensuring a controlled release of the entrapped drug. We studied the colonic-targeting behavior, in vivo toxicity test, pharmacokinetic study, features to reduce drug toxicity, and therapeutic effect of experimental UC of this preparation. All the results in vitro were shown that the K (KGM-XG-GLY-SA) hydrogels with glycerol had a good colon-targeting characteristic. In addition, results in vivo were indicated that K (KGM-XG-GLY-SA) hydrogel were nontoxic, reduced the spleen and thymus index, and had an obvious effect on the treatment of UC. Therefore, all results suggested that the developed HSS/KGM-XG-GLY-SA hydrogel (HSS-GEL) with glycerol as a colon-targeting vector might have greatly potential application in the UC healing. PMID:26076623

  14. In vitro percutaneous absorption and in vivo protoporphyrin IX accumulation in skin and tumors after topical 5-aminolevulinic acid application with enhancement using an erbium:YAG laser.

    PubMed

    Shen, Shing-Chuan; Lee, Woan-Ruoh; Fang, Yi-Ping; Hu, Chung-Hong; Fang, Jia-You

    2006-04-01

    5-aminolevulinic acid (ALA) is used as a precursor of protoporphyrin IX (PpIX) for photodynamic therapy (PDT) of superficial skin cancers and subcutaneous metastases of internal malignancies. The permeability of ALA across intact skin is always low, making it difficult to achieve the desired therapeutic benefits. Hence new methods for enhancing ALA permeation are urgently needed. The aim of this study was to determine the in vivo kinetics of PpIX generation in mouse tissues after topical ALA application enhanced by an erbium (Er):yttrium-aluminum-garnet (YAG) laser. The in vitro permeation of ALA was also used to screen the optimal method for the in vivo study. The efficacy of the improved drug delivery was determined as a function of various laser fluences and cancer models. ALA applied to laser-treated skin produced a higher accumulations of PpIX within superficial skin and subcutaneous tumors as compared to those of the non-treated group (t-test, p < 0.05). The enhancement ratios (ER) of laser-treated skin ranged from 1.7 to 4.9 times as compared to the control depending to the fluences used. The enhanced PpIX level of laser-treated skin was generally more pronounced in normal and lesional skin than in subcutaneous nodular tumors. Confocal laser scanning microscopy (CLSM) of laser-treated skin revealed intense red fluorescence within the epidermis and upper dermis, and a much-weaker fluorescence within the bottom layers of the skin. On the other hand, the fluorescence intensity of the control group was much lower than that of laser-treated group. The barrier properties of the skin irradiated by the laser had completely recovered within 3 days. Pretreatment of skin using an Er:YAG laser was useful in increasing the amount of Pp IX within skin tumors. PMID:16493590

  15. Photoactivatable Nanostructured Surfaces for Biomedical Applications.

    PubMed

    Mosinger, Ji?; Lang, Kamil; Kubt, Pavel

    2016-01-01

    This review aims to summarize the current status of photoactivatable nanostructured film and polymeric nanofiber surfaces used in biomedical applications with emphasis on their photoantimicrobial activity, oxygen-sensing in biological media, light-triggered release of drugs, and physical or structural transformations. Many light-responsive functions have been considered as novel ways to alter surfaces, i.e., in terms of their reactivities and structures. We describe the design of surfaces, nano/micro-fabrication, the properties affected by light, and the application principles. Additionally, we compare the various approaches reported in the literature. PMID:26589508

  16. Intermolecular double-quantum coherence imaging without coherence selection gradients and its application in in vivo MRI.

    PubMed

    Shen, Guiping; Cai, Congbo; Chen, Zhong; Cai, Shuhui

    2013-05-01

    In the COSY Revamped with Asymmetric Z-gradient Echo Detection (CRAZED) experiments, magnetization is modulated by the distant dipolar field (DDF) generated by coherence selection gradient (CSG) commonly in sinusoidal wave-form and results in detectable intermolecular multiple-quantum coherence (iMQC) signal. IMQCs have some attractive features, but their intrinsic weak signal intensity prevents their widespread applications. In this paper, a new phase cycling scheme was applied to obtain intermolecular double-quantum coherence (iDQC) signal. It is found that DDF can arise from nonspherical sample geometry or background inhomogeneous field in the absence of CSGs, which is more efficient than that created from CSGs. The experimental results show that the resulting DDF can refocus the iDQC signals simultaneously and thus enhance the signal intensity to about two folds of that from the conventional CRAZED sequence. Theoretical prediction and experiments give coincident results. PMID:23473838

  17. Optical imaging in vivo with a focus on paediatric disease: technical progress, current preclinical and clinical applications and future perspectives

    PubMed Central

    Napp, Joanna; Mathejczyk, Julia E.

    2011-01-01

    To obtain information on the occurrence and location of molecular events as well as to track target-specific probes such as antibodies or peptides, drugs or even cells non-invasively over time, optical imaging (OI) technologies are increasingly applied. Although OI strongly contributes to the advances made in preclinical research, it is so far, with the exception of optical coherence tomography (OCT), only very sparingly applied in clinical settings. Nevertheless, as OI technologies evolve and improve continuously and represent relatively inexpensive and harmful methods, their implementation as clinical tools for the assessment of children disease is increasing. This review focuses on the current preclinical and clinical applications as well as on the future potential of OI in the clinical routine. Herein, we summarize the development of different fluorescence and bioluminescence imaging techniques for microscopic and macroscopic visualization of microstructures and biological processes. In addition, we discuss advantages and limitations of optical probes with distinct mechanisms of target-detection as well as of different bioluminescent reporter systems. Particular attention has been given to the use of near-infrared (NIR) fluorescent probes enabling observation of molecular events in deeper tissue. PMID:21221568

  18. Theory and application of optimal linear resolution to MRI truncation artifacts, multiexponential decays and in vivo multiple sclerosis pathology

    NASA Astrophysics Data System (ADS)

    Cover, Keith S.

    It is widely believed that one of the best way to proceed when analysing data is to generate estimates which fit the data. However, when the relationship between the unknown model and data is linear for highly underdetermined systems, is it common practice to find estimates with good linear resolution with no regard for fitting the data. For example, windowed Fourier transforms produces estimates that have good linear resolution but do not fit the data. Surprisingly, many researchers do not seem to be explicitly aware of this fact. This thesis presents a theoretical basis for the linear resolution which demonstrates that, for a wide range of problems, algorithms which produce estimates with good linear resolution can be a more powerful and convenient way of presenting the information in the data, than models that fit the data. Linear resolution was also applied to two outstanding problems in linear inverse theory. The first was the problem of truncation artifacts in magnetic resonance imaging (MRI). Truncation artifacts were heavily suppressed or eliminated by the choice of one of two novel Fourier transform windows. Complete elimination of truncation artifacts generally led to unexpectedly blurry images. Heavy suppression seemed to be the best compromise between truncation artifacts and blurriness. The second problem was estimating the relaxation distribution of a multiexponential system from its decay curve. This is an example where hundreds of papers have been written on the subject, yet almost no one has made a substantial effort to apply linear resolution. I found the application to be very successful. As an example, the algorithm was applied to the decay of MRI data from multiple sclerosis patients in an attempt to differentiate between various pathologies.

  19. 3D reconstruction of 2D fluorescence histology images and registration with in vivo MR images: application in a rodent stroke model.

    PubMed

    Stille, Maik; Smith, Edward J; Crum, William R; Modo, Michel

    2013-09-30

    To validate and add value to non-invasive imaging techniques, the corresponding histology is required to establish biological correlates. We present an efficient, semi-automated image-processing pipeline that uses immunohistochemically stained sections to reconstruct a 3D brain volume from 2D histological images before registering these with the corresponding 3D in vivo magnetic resonance images (MRI). A multistep registration procedure that first aligns the "global" volume by using the centre of mass and then applies a rigid and affine alignment based on signal intensities is described. This technique was applied to a training set of three rat brain volumes before being validated on three normal brains. Application of the approach to register "abnormal" images from a rat model of stroke allowed the neurobiological correlates of the variations in the hyper-intense MRI signal intensity caused by infarction to be investigated. For evaluation, the corresponding anatomical landmarks in MR and histology were defined to measure the registration accuracy. A registration error of 0.249 mm (approximately one in-plane voxel dimension) was evident in healthy rat brains and of 0.323 mm in a rodent model of stroke. The proposed reconstruction and registration pipeline allowed for the precise analysis of non-invasive MRI and corresponding microstructural histological features in 3D. We were thus able to interrogate histology to deduce the cause of MRI signal variations in the lesion cavity and the peri-infarct area. PMID:23816399

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

    PubMed

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

    2015-03-01

    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

  1. Resistance after chronic application of the HDAC-inhibitor valproic acid is associated with elevated Akt activation in renal cell carcinoma in vivo.

    PubMed

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

    2013-01-01

    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

  2. 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)

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

    2012-11-01

    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.

  3. Two-Photon Absorbing Dyes with Minimal Autofluorescence in Tissue Imaging: Application to in Vivo Imaging of Amyloid-? Plaques with a Negligible Background Signal.

    PubMed

    Kim, Dokyoung; Moon, Hyunsoo; Baik, Sung Hoon; Singha, Subhankar; Jun, Yong Woong; Wang, Taejun; Kim, Ki Hean; Park, Byung Sun; Jung, Junyang; Mook-Jung, Inhee; Ahn, Kyo Han

    2015-06-01

    Fluorescence imaging of tissues offer an essential means for studying biological systems. Autofluorescence becomes a serious issue in tissue imaging under excitation at UV-vis wavelengths where biological molecules compete with the fluorophore. To address this critical issue, a novel class of fluorophores that can be excited at ?900 nm under two-photon excitation conditions and emits in the red wavelength region (?600 nm) has been disclosed. The new ?-extended dipolar dye system shows several advantageous features including minimal autofluorescence in tissue imaging and pronounced solvent-sensitive emission behavior, compared with a widely used two-photon absorbing dye, acedan. As an important application of the new dye system, one of the dyes was developed into a fluorescent probe for amyloid-? plaques, a key biomarker of Alzheimer's disease. The probe enabled in vivo imaging of amyloid-? plaques in a disease-model mouse, with negligible background signal. The new dye system has great potential for the development of other types of two-photon fluorescent probes and tags for imaging of tissues with minimal autofluorescence. PMID:25951499

  4. Mathematical models to describe iontophoretic transport in vitro and in vivo and the effect of current application on the skin barrier.

    PubMed

    Gratieri, Tas; Kalia, Yogeshvar N

    2013-02-01

    The architecture and composition of the stratum corneum make it a particularly effective barrier against the topical and transdermal delivery of hydrophilic molecules and ions. As a result, different strategies have been explored in order to expand the range of therapeutic agents that can be administered by this route. Iontophoresis involves the application of a small electric potential to increase transport into and across the skin. Since current flow is preferentially via transport pathways with at least some aqueous character, it is ideal for hydrosoluble molecules containing ionisable groups. Hence, the physicochemical properties that limit partitioning and passive diffusion through the intercellular lipid matrix are beneficial for electrically-assisted delivery. The presence of fixed ionisable groups in the skin (pI 4-4.5) means that application of the electric field results in a convective solvent flow (i.e., electroosmosis) in the direction of ion motion so as to neutralise membrane charge. Hence, under physiological conditions, cation electrotransport is due to both electromigration and electroosmosis-their relative contribution depends on the formulation conditions and the physicochemical properties of the permeant. Different mathematical models have been developed to provide a theoretical framework in order to explain iontophoretic transport kinetics. They usually involve solutions of the Nernst-Planck equation - using either the constant field (Goldman) or electroneutrality (Nernst) approximations - with or without terms for the convective solvent flow component. Investigations have also attempted to elucidate the nature of ion transport pathways and to explain the effect of current application on the electrical properties of the skin-more specifically, the stratum corneum. These studies have led to the development of different equivalent circuit models. These range from simple parallel arrangements of a resistor and a capacitor to the inclusion of the more esoteric "constant phase element"; the latter provides a better mathematical description of the "non-ideal" behaviour of skin impedance. However, in addition to simply providing a "mathematical" fit of the observed data, it is essential to relate these circuit elements to biological structures present in the skin. More recently, attention has also turned to what happens when the permeant crosses the epidermis and reaches the systemic circulation and pharmacokinetic models have been proposed to interpret data from iontophoretic delivery studies in vivo. Here, we provide an overview of mathematical models that have been proposed to describe (i) the effect of current application on the skin and the implications for potential iontophoretic transport pathways, (ii) electrotransport kinetics and (iii) the fate of iontophoretically delivered drugs once they enter the systemic circulation. PMID:22626977

  5. Effects of fluoride-ion-implanted titanium surface on the cytocompatibility in vitro and osseointegatation in vivo for dental implant applications.

    PubMed

    Wang, Xue-Jin; Liu, Hui-Ying; Ren, Xiang; Sun, Hui-Yan; Zhu, Li-Ying; Ying, Xiao-Xia; Hu, Shu-Hai; Qiu, Ze-Wen; Wang, Lang-Ping; Wang, Xiao-Feng; Ma, Guo-Wu

    2015-12-01

    As an attractive technique for the improvement of biomaterials, Plasma immersion ion implantation (PIII) has been applied to modifying the titanium material for dental implant application. The present study investigated the cytocompatibility and early osseointegration of fluoride-ion-implanted titanium (F-Ti) surface and implants, both characterizing in their composition of titanium oxide and titanium fluoride. The cytocompatibility of F-Ti was evaluated in vitro by using scanning electron microscope, Cell Counting Kit-8 assay, alkaline phosphatase activity assay, and quantitative real-time polymerase chain reaction. The results showed that the F-Ti weakened the effects that Porphyromonas gingivalis exerted on the MG-63 cells in terms of morphology, proliferation, differentiation, and genetic expression when MG-63 cells and Porphyromonas gingivalis were co-cultured on the surface of F-Ti. Meanwhile, the osteogenic activity of F-Ti implants was assessed in vivo via evaluating the histological morphology and estimating histomorphometric parameters. The analysis of toluidine blue staining indicated that the new bone was more mature in subjects with F-Ti group, which exhibited the Haversian system, and the mean bone-implant contact value of F-Ti group was slightly higher than that of cp-Ti group (p>0.05). Fluorescence bands were wider and brighter in the F-Ti group, and the intensity of fluorochromes deposited at the sites of mineralized bone formation was significantly higher for F-Ti surfaces than for cp-Ti surfaces, within the 2nd, 3rd and 4th weeks (p<0.05). An indication is that the fluoride modified titanium can promote cytocompatibility and early osseointegration, thus providing a promising alternative for clinical use. PMID:26519937

  6. ITRAQ MASS SPECTROMETRIC PROTEOMIC APPLICATIONS FOR IN VIVO TOXICOLOGY STUDIES OF AMPHIBIAN SPECIES: DATA HANDLING AND INTERPRETATION USING PEPTIDE-TAGGING SOFTWARE

    EPA Science Inventory

    This addresses the USEPA's need for a cost effective, non-mammalian screening assay for thyroid axis disrupting chemicals; a multi-endpoint strategy combining molecular and in vivo protocols in an amphibian model is being applied at MED Duluth.

  7. Ex vivo lung perfusion

    PubMed Central

    Machuca, Tiago N.

    2014-01-01

    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

  8. 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)

    Masters, Barry R.

    1995-05-01

    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.

  9. Synthesis, radiolabeling with fluorine-18 and preliminary in vivo evaluation of a heparan sulphate mimetic as potent angiogenesis and heparanase inhibitor for cancer applications.

    PubMed

    Kuhnast, B; El Hadri, A; Boisgard, R; Hinnen, F; Richard, S; Caravano, A; Nancy-Portebois, V; Petitou, M; Tavitian, B; Doll, F

    2016-02-01

    Heparan Sulfate (HS) mimetics are able to block crucial interactions of the components of the extracellular matrix in angiogenic processes and as such, represent a valuable class of original candidates for cancer therapy. Here we first report the synthesis and in vitro angiogenic inhibition properties of a conjugated, novel and rationally-designed octasaccharide-based HS mimetic. We also herein report its labeling with fluorine-18 and present the preliminary in vivo Positron Emission Tomography imaging data in rats. This constitutes one of the rare examples of labeling and in vivo evaluation of a synthetic, polysaccharide-based, macromolecule. PMID:26757783

  10. In vivo biotinylated recombinant antibodies: high efficiency of labelling and application to the cloning of active anti-human IgG1 Fab fragments.

    PubMed

    Sibler, A P; Kempf, E; Glacet, A; Orfanoudakis, G; Bourel, D; Weiss, E

    1999-04-22

    In vivo biotinylation of antibody fragments with a gene fusion approach is a realistic alternative to conventional in vitro chemical labelling. We have previously reported the construction of a vector system suitable for the bacterial expression of the binding fragment of antibody (Fab) genetically linked to the C-terminal domain of Escherichia Coli biotin carboxy carrier protein (BCCP*). A minor fraction of the expressed hybrids was biotinylated in vivo and therefore able to interact with streptavidin. We now show that the large majority of bacterially-expressed Fab-BCCP* fusions are labelled with biotin when plasmid-encoded biotin holoenzyme synthetase (BirA) is co-expressed. The yield of biotinylated Fab is maximal when overexpression of BirA is driven by a second compatible plasmid. We took advantage of this property to develop a novel filter assay for the rapid identification of recombinant Fab reacting with immunoglobulin. Starting with total RNA of two newly established murine hybridoma cell lines producing anti-human IgG1 antibodies, we selected in a single experiment the bacterial clones that expressed in vivo biotinylated anti-IgG1 Fab. Sequence analysis of the isolated Fabs showed that they did not derive from a single B clone. In addition, we found that these recombinant Fabs labelled with biotin in vivo are useful for the specific detection of human IgG1 by a solid-phase immunoassay. PMID:10357213

  11. A fluorescent switchable AIE probe for selective imaging of dipeptidyl peptidase-4 in vitro and in vivo and its application in screening DPP-4 inhibitors.

    PubMed

    Wang, Yi; Wu, Xueli; Cheng, Yiyu; Zhao, Xiaoping

    2016-02-28

    A novel fluorescent probe for in vitro and in vivo imaging of dipeptidyl peptidase-4 (DPP-4) was designed and synthesized. This probe is successfully utilized to screen DPP-4 inhibitors in living 3T3-L1 cells and zebrafish, which provides a novel approach for the discovery of anti-diabetes drugs. PMID:26812581

  12. Application of a convective-dispersion model to predict in vivo hepatic clearance from in vitro measurements utilizing cryopreserved human hepatocytes.

    PubMed

    Niro, Ryan; Byers, James P; Fournier, Ronald L; Bachmann, Kenneth

    2003-10-01

    Growing interest in the prediction of in vivo pharmacokinetic data from purely in vitro data has grown into a process known as the in vitro-in vivo correlation (IVIC). IVIC can be used to determine the viability of new chemical entities in the early drug development phases, leading to a reduction of resource spending by many large pharmaceutical companies. Here, a convective-dispersion model was developed to predict the total hepatic clearance of six drugs using pharmacokinetic data obtained from in vitro metabolism studies in which the drug disappearance from suspensions of human cryopreserved hepatocytes was measured. Predicted in vivo hepatic clearances estimated by the convective-dispersion model were ultimately compared to the actual clearance values and to in vivo hepatic clearances that were scaled based on the well-stirred model. Finally, sensitivity studies were performed to determine the dependence of hepatic clearance on a number of physiological model parameters. Results reaffirmed that low clearance drugs exhibit rate-limited metabolism, and their hepatic clearances are thus independent of blood flow characteristics, whereas drugs with relatively higher clearance values show a more pronounced dependence on the flood flow properties of dispersion and convection. Absent a priori knowledge about the flow-dependent properties of a drug's clearance, the convective dispersion model applied to disappearance data acquired from cryopreserved human hepatocytes is likely to provide satisfactory estimates of hepatic drug clearance. PMID:14529368

  13. 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...

  14. Feasibility and application of a retronasal aroma-trapping device to study in vivo aroma release during the consumption of model wine-derived beverages

    PubMed Central

    Muoz-Gonzlez, Carolina; Rodrguez-Bencomo, Juan Jos; Moreno-Arribas, Maria Victoria; Pozo-Bayn, Maria ngeles

    2014-01-01

    New types of wine-derived beverages are now in the market. However, little is known about the impact of ingredient formulation on aroma release during consumption, which is directly linked to consumer preferences and liking. In this study, the optimization and validation of a retronasal aroma-trapping device (RATD) for the in vivo monitoring of aroma release was carried out. This device was applied to assess the impact of two main ingredients (sugar and ethanol) in these types of beverages on in vivo aroma release. Two aroma-trapping materials (Lichrolut and Tenax) were firstly assayed. Tenax provided higher recovery and lower intra- and inter-trap variability. In in vivo conditions, RATD provided an adequate linear range (R2 > 0.91) between 0 and 50 mg L?1 of aroma compounds. Differences in the total aroma release were observed in equally trained panelists. It was proven that the addition of sugar (up to 150 mg kg?1) did not have effect on aroma release, while ethanol (up to 40 mg L?1) enhanced the aroma release during drinking. The RATD is a useful tool to collect real in vivo data to extract reliable conclusions about the effect of beverage components on aroma release during consumption. The concentration of ethanol should be taken into consideration for the formulation of wine-derived beverages. PMID:25473493

  15. Six DOF in vivo kinematics of the ankle joint complex: Application of a combined dual-orthogonal fluoroscopic and magnetic resonance imaging technique.

    PubMed

    de Asla, Richard J; Wan, Lu; Rubash, Harry E; Li, Guoan

    2006-05-01

    Accurate knowledge of in vivo ankle joint complex (AJC) biomechanics is critical for understanding AJC disease states and for improvement of surgical treatments. This study investigated 6 degrees-of-freedom (DOF) in vivo kinematics of the human AJC using a combined dual-orthogonal fluoroscopic and magnetic resonance imaging (MRI) technique. Five healthy ankles of living subjects were studied during three in vivo activities of the foot, including maximum plantarflexion and dorsiflexion, maximum supination and pronation, and three weight-bearing positions in simulated stance phases of walking. A three-dimensional (3D) computer model of the AJC (including tibia, fibula, talus, and calcaneus) was constructed using 3D MR images of the foot. The in vivo AJC position at each selected position of the foot was captured using two orthogonally positioned fluoroscopes. In vivo AJC motion could then be reproduced by coupling the orthogonal images with the 3D AJC model in a virtual dual-orthogonal fluoroscopic system. From maximum dorsiflexion to plantarflexion, the arc of motion of the talocrural joint (47.5 +/- 2.2 degrees) was significantly larger than that of the subtalar joint (3.1 +/- 6.8 degrees). Both joints showed similar degrees of internal-external and inversion-eversion rotation. From maximum supination to pronation, all rotations and translations of the subtalar joint were significantly larger than those of the talocrural joint. From heel strike to midstance, the plantarflexion contribution from the talocrural joint (9.1 +/- 5.3 degrees) was significantly larger than that of the subtalar joint (-0.9 +/- 1.2 degrees). From midstance to toe off, internal rotation and inversion of the subtalar joint (12.3 +/- 8.3 degrees and -10.7 +/- 3.8 degrees, respectively) were significantly larger than those of the talocrural joint (-1.6 +/- 5.9 degrees and -1.7 +/- 2.7 degrees). Strong kinematic coupling between the talocrural and subtalar joints was observed during in vivo AJC activities. The contribution of the talocrural joint to active dorsi-plantarflexion was higher than that of the subtalar joint, whereas the contribution of the subtalar joint to active supination-pronation was higher than that of the talocrural joint. In addition, the talocrural joint demonstrated larger motion during the early part of stance phase while the subtalar joint contributes more motion during the later part of stance phase. The results add quantitative data to an in vivo database of normals that can be used in clinical diagnosis, treatment, and evaluation of the AJC after injuries. PMID:16609963

  16. In vivo imaging flow cytometer

    NASA Astrophysics Data System (ADS)

    Lee, Ho; Alt, Clemens; Pitsillides, Costas M.; Puoris'haag, Mehron; Lin, Charles P.

    2006-08-01

    We introduce an in vivo imaging flow cytometer, which provides fluorescence images simultaneously with quantitative information on the cell population of interest in a live animal. As fluorescent cells pass through the slit of light focused across a blood vessel, the excited fluorescence is confocally detected. This cell signal triggers a strobe beam and a high sensitivity CCD camera that captures a snapshot image of the cell as it moves down-stream from the slit. We demonstrate that the majority of signal peaks detected in the in vivo flow cytometer arise form individual cells. The instruments capability to image circulating T cells and measure their speed in the blood vessel in real time in vivo is demonstrated. The cell signal irradiance variation, clustering percentage, and potential applications in biology and medicine are discussed.

  17. Successful application of serum shift prediction models to the design of dual targeting inhibitors of bacterial gyrase B and topoisomerase IV with improved in vivo efficacy.

    PubMed

    Perola, Emanuele; Stamos, Dean; Grillot, Anne-Laure; Ronkin, Steven; Wang, Tiansheng; LeTiran, Arnaud; Tang, Qing; Deininger, David D; Liao, Yusheng; Tian, Shi-Kai; Drumm, Joseph E; Nicolau, David P; Tessier, Pamela R; Mani, Nagraj; Grossman, Trudy H; Charifson, Paul S

    2014-05-01

    A series of dual targeting inhibitors of bacterial gyrase B and topoisomerase IV were identified and optimized to mid-to-low nanomolar potency against a variety of bacteria. However, in spite of seemingly adequate exposure achieved upon IV administration, the in vivo efficacy of the early lead compounds was limited by high levels of binding to serum proteins. To overcome this limitation, targeted serum shift prediction models were generated for each subclass of interest and were applied to the design of prospective analogs. As a result, numerous compounds with comparable antibacterial potency and reduced protein binding were generated. These efforts culminated in the synthesis of compound 10, a potent inhibitor with low serum shift that demonstrated greatly improved in vivo efficacy in two distinct rat infection models. PMID:24685546

  18. Method for the analysis of contribution of sliding and hopping to a facilitated diffusion of DNA-binding protein: Application to in vivo data

    NASA Astrophysics Data System (ADS)

    Tabaka, Marcin; Burdzy, Krzysztof; Ho?yst, Robert

    2015-08-01

    DNA-binding protein searches for its target, a specific site on DNA, by means of diffusion. The search process consists of many recurrent steps of one-dimensional diffusion (sliding) along the DNA chain and three-dimensional diffusion (hopping) after dissociation of a protein from the DNA chain. Here we propose a computational method that allows extracting the contribution of sliding and hopping to the search process in vivo from the measurements of the kinetics of the target search by the lac repressor in Escherichia coli [P. Hammar et al., Science 336, 1595 (2012), 10.1126/science.1221648]. The method combines lattice Monte Carlo simulations with the Brownian excursion theory and includes explicitly steric constraints for hopping due to the helical structure of DNA. The simulation results including all experimental data reveal that the in vivo target search is dominated by sliding. The short-range hopping to the same base pair interrupts one-dimensional sliding while long-range hopping does not contribute significantly to the kinetics of the search of the target in vivo.

  19. A functional radioreceptor assay of alpha-V-beta-3 (alphavbeta3) inhibitors in plasma: application as an ex vivo pharmacodynamic model.

    PubMed

    Chaikin, Margery A; Marugan, Jan Jos; De Vries, Gerald W; Baciu, Peter; Edelman, Jeffrey; Ni, Ming; Tomczuk, Bruce E; Pan, Wenxi; Guo, Zihong; Anaclerio, Beth; Leonard, Kristi; Eisennagel, Stephen H; Molloy, Christopher J; Manthey, Carl L

    2005-12-31

    Development of alphavbeta3-integrin inhibitors has been hampered by a lack of pharmacodynamic endpoints to identify doses that inhibit alphavbeta3 in vivo. To address this need, we developed an alphavbeta3 radioreceptor assay (RRA) that could be performed in 100% plasma. The RRA was based on 125I-echistatin binding to plate-immobilized alphavbeta3. Small molecule alphavbeta3 inhibitors efficiently competed echistatin binding to alphavbeta3 when the assay was carried out in buffer. However, when carried out in 100% plasma, the RRA revealed a 45 to >3000-fold loss in compound potencies. The losses in potency reflected, in part, the high plasma protein binding by the compounds examined. The RRA was adapted as an ex vivo pharmacodynamic model. Echistatin binding was measured in the presence of plasma harvested at timed intervals from rats dosed with select compounds. Using this pharmacodynamic model, compound and dose selection was optimized for further testing in models of corneal angiogenesis. Moderate anti-angiogenic activity was achieved when rats were dosed sufficient to achieve sustained (>50%) plasma inhibition through the trough interval. Thus, the RRA provided a simple technique to rank order compound potency in plasma, and could find general use as an ex vivo pharmacodynamic assay to select compounds and doses for preclinical and clinical proof-of-principle studies. PMID:16325916

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

    PubMed

    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

    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

  1. PK/PD assessment in CNS drug discovery: Prediction of CSF concentration in rodents for P-glycoprotein substrates and application to in vivo potency estimation.

    PubMed

    Caruso, Antonello; Alvarez-Snchez, Ruben; Hillebrecht, Alexander; Poirier, Agns; Schuler, Franz; Lav, Thierry; Funk, Christoph; Belli, Sara

    2013-06-01

    The unbound drug concentration in brain parenchyma is considered to be the relevant driver for interaction with central nervous system (CNS) biological targets. Drug levels in cerebrospinal fluid (C_CSF) are frequently used surrogates for the unbound concentrations in brain. For drugs actively transported across the blood-brain barrier (BBB), C_CSF differs from unbound plasma concentration (Cu_p) to an extent that is commonly unknown. In this study, the relationship between CSF-to-unbound plasma drug partitioning in rats and the mouse Pgp (Mdr1a) efflux ratio (ER) obtained from in vitro transcellular studies has been investigated for a set of 61 CNS compounds exhibiting substantial diversity in chemical structure and physico-chemical properties. In order to understand the in vitro-in vivo extrapolation of Pgp efflux, a mechanistic model was derived relating in vivo CNS distribution kinetics to in vitro active transport. The model was applied to predict C_CSF from Cu_p and ER data for 19 proprietary Roche CNS drug candidates. The calculated CSF concentrations were correlated with CNS pharmacodynamic responses observed in rodent models. The correlation between in vitro and in vivo potency for different pharmacological endpoints indicated that the predicted C_CSF is a valuable surrogate of the concentration at the target site. Overall, C_CSF proved superior description of PK/PD data than unbound plasma or total brain concentration for Mdr1a substrates. Predicted C_CSF can be used as a default approach to understand the PK/PD relationships in CNS efficacy models and can support the extrapolation of efficacious brain exposure for new drug candidates from rodent to man. PMID:23454189

  2. The application of anti-ESAT-6 monoclonal antibody fluorescent probe in ex vivo near-infrared fluorescence imaging in mice with pulmonary tuberculosis.

    PubMed

    Feng, Feng; Zhang, Haoling; Zhu, Zhaoqin; Li, Cong; Shi, Yuxin; Zhang, Zhiyong

    2014-09-01

    Here, we aimed to assess the feasibility of anti-ESAT-6 monoclonal antibody (mAb) coupling with IR783 and rhodamine fluorescent probe in the detection of ESAT-6 expression in tuberculosis tissue of mice using near-infrared fluorescence imaging. IR783 and rhodamine were conjugated to the anti-ESAT-6 mAb or IgG. Mice in the experimental group were injected with fluorescence-labeled mAb probe, and mice in the control group were injected with fluorescence-labeled non-specific IgG antibody. Twenty-four hours later, the lung tissue of mice was examined using ex vivo near-infrared fluorescence imaging. In addition, the contrast-to-noise ratio (CNR) was calculated by measuring the signal intensities of the pulmonary lesions, normal lung tissue and background noise. The frozen lung tissue section was examined under fluorescence microscopy and compared with hemoxylin and eosin (HE) staining. The ex vivo near-infrared fluorescence imaging showed that the fluorescence signal in the lung tuberculosis lesions in the experimental group was significantly enhanced, whereas there was only a weak fluorescence signal or even no fluorescence signal in the control group. CNR values were 64.40 ± 7.02 (n = 6) and 8.75 ± 3.87 (n = 6), respectively (t = 17.01, p < 0.001). The fluorescence accumulation distribution detected under fluorescence microscopy was consistent with HE staining of the tuberculosis region. In conclusion, anti-ESAT-6 mAb fluorescent probe could target and be applied in specific ex vivo imaging of mice tuberculosis, and may be of further use in tuberculosis in living mice. PMID:24170605

  3. Optimisations and Challenges Involved in the Creation of Various Bioluminescent and Fluorescent Influenza A Virus Strains for In Vitro and In Vivo Applications

    PubMed Central

    Herfst, Sander; Bestebroer, Theo M.; Vaes, Vincent P.; van der Hoeven, Barbara; Koster, Abraham J.; Kremers, Gert-Jan; Scott, Dana P.; Gultyaev, Alexander P.; Sorell, Erin M.; de Graaf, Miranda; Bárcena, Montserrat; Rimmelzwaan, Guus F.; Fouchier, Ron A.

    2015-01-01

    Bioluminescent and fluorescent influenza A viruses offer new opportunities to study influenza virus replication, tropism and pathogenesis. To date, several influenza A reporter viruses have been described. These strategies typically focused on a single reporter gene (either bioluminescent or fluorescent) in a single virus backbone. However, whilst bioluminescence is suited to in vivo imaging, fluorescent viruses are more appropriate for microscopy. Therefore, the idea l reporter virus varies depending on the experiment in question, and it is important that any reporter virus strategy can be adapted accordingly. Herein, a strategy was developed to create five different reporter viruses in a single virus backbone. Specifically, enhanced green fluorescent protein (eGFP), far-red fluorescent protein (fRFP), near-infrared fluorescent protein (iRFP), Gaussia luciferase (gLUC) and firefly luciferase (fLUC) were inserted into the PA gene segment of A/PR/8/34 (H1N1). This study provides a comprehensive characterisation of the effects of different reporter genes on influenza virus replication and reporter activity. In vivo reporter gene expression, in lung tissues, was only detected for eGFP, fRFP and gLUC expressing viruses. In vitro, the eGFP-expressing virus displayed the best reporter stability and could be used for correlative light electron microscopy (CLEM). This strategy was then used to create eGFP-expressing viruses consisting entirely of pandemic H1N1, highly pathogenic avian influenza (HPAI) H5N1 and H7N9. The HPAI H5N1 eGFP-expressing virus infected mice and reporter gene expression was detected, in lung tissues, in vivo. Thus, this study provides new tools and insights for the creation of bioluminescent and fluorescent influenza A reporter viruses. PMID:26241861

  4. Insight into the efficient transfection activity of a designed low aggregated magnetic polyethyleneimine/DNA complex in serum-containing medium and the application in vivo.

    PubMed

    Xie, Li; Jiang, Qian; He, Yiyan; Nie, Yu; Yue, Dong; Gu, Zhongwei

    2015-03-01

    A designed low aggregated magnetic polyethyleneimine/DNA (MPD-cc) complex showed efficient transfection in serum-containing medium for PEI-mediated gene transfection in vitro and in vivo, but the mechanism remains unclear. The present study provides an insight into the extracellular and intracellular fates of the magnetic gene complexes, evaluates their transfection efficiency and body distribution after systemic administration assisted by fluorescent imaging technology. The PEI cationic complexes in our study switched to be negatively charged in the serum-containing medium due to protein corona formation, and the complexes displayed negligible aggregation from transmission electron microscopy observation and dynamic light scattering analysis. However, the SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed that less protein was adsorbed on the magnetic gene complexes during a 10 min magnetofection compared with that associated with traditional polyethyleneimine/DNA (PD) complexes after a long-term (4 h) incubation. In terms of cellular uptake and internalization evaluation by flow cytometry, magnetofection with our designed MPD-cc complexes showed obvious superiority in the presence of serum, compared to traditional transfection (PD complexes). Moreover, confocal laser scanning microscopy revealed that after internalization, fewer MPD-cc with magnetofection were trapped in the endosome and more found in the nucleus compared to the PD and MPD-cc without the magnetic field. Putting these facts together, we conclude that magnetofection by the designed MPD-cc complexes facilitates many processes of transfection, including less protein adsorption, efficient cellular sedimentation and internalization, as well as endosomal escape and nuclear import. In the near infrared imaging study, it was observed that the accumulation of complexes in tumors by magnetic capture was enhanced in vivo. All of these improved in vitro and in vivo functions contributed to a 5-fold enhancement in magnetofection via intravenous delivery. PMID:26222288

  5. A new ex vivo beating heart model to investigate the application of heart valve performance tools with a high-speed camera.

    PubMed

    Kondruweit, Markus; Friedl, Sven; Heim, Christian; Wittenberg, Thomas; Weyand, Michael; Harig, Frank

    2014-01-01

    High-speed camera examination of heart valves is an established technique to examine heart valve prosthesis. The aim of this study was to examine the possibility to transmit new tools for high-speed camera examination of heart valve behavior under near-physiological conditions in a porcine ex vivo beating heart model. After explantation of the piglet heart, main coronary arteries were cannulated and the heart was reperfused with the previously collected donor blood. When the heart started beating in sinus rhythm again, the motion of the aortic and mitral valve was recorded using a digital high-speed camera system (recording rate 2,000 frames/sec). The image sequences of the mitral valve were analyzed, and digital kymograms were calculated at different angles for the exact analysis of the different closure phases. The image sequence of the aortic valve was analyzed, and several snakes were performed to analyze the effective orifice area over the time. Both processing tools were successfully applied to examine heart valves in this ex vivo beating heart model. We were able to investigate the exact open and closure time of the mitral valve, as well as the projected effective orifice area of the aortic valve over the time. The high-speed camera investigation in an ex vivo beating heart model of heart valve behavior is feasible and also reasonable because of using processing feature such as kymography for exact analysis. These analytical techniques might help to optimize reconstructive surgery of the mitral valve and the development of heart valve prostheses in future. PMID:24270227

  6. 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

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

    2014-01-01

    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

  7. Applicability of the Rayleigh equation for enantioselective metabolism of chiral xenobiotics by microsomes, hepatocytes and in-vivo retention in rabbit tissues.

    PubMed

    Jammer, Shifra; Gelman, Faina; Lev, Ovadia

    2016-01-01

    In this study we propose a new approach for analyzing the enantioselective biodegradation of some antidepressant drugs mediated by human and rat liver microsomes by using the Rayleigh equation to describe the enantiomeric enrichment-conversion dependencies. Analysis of reported degradation data of additional six pesticides, an alpha blocker and a flame retardant by microsomes or hepatocytes in vitro reaffirmed the universality of the approach. In all the in vitro studied cases that involved enantioselective degradation, a Rayleigh dependence of the enantiomeric enrichment was observed. Published data regarding in vivo retention of myclobutanil in liver, kidney, muscle and brain tissues of rabbits following injection of the racemate were remodeled showing prevalence of the Rayleigh law for the chiral enrichment of the fungicide in the various tissues. This approach will revolutionize data organization in metabolic pathway research of target xenobiotics by either liver microsomes, hepatocytes or their organ-specific in vivo retention. The fact that the enantiomeric enrichment as a function of the conversion can be described by a single quantifier, will pave the road for the use of structure activity predictors of the enantiomeric enrichment and for mechanistic discrimination based on parametric dependence of the quantifier. PMID:27021918

  8. Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application.

    PubMed

    Tegafaw, Tirusew; Xu, Wenlong; Ahmad, Md Wasi; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

    2015-09-11

    A new type of dual-mode T1 and T2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd(3+) ((8)S7/2) plays an important role in T1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy(3+) ((6)H15/2) has the potential to be used in T2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy2O3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd(3+) and Dy(3+) and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T1 and T2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (davg=1.0 nm) showed large r1 and r2 values (r2/r1?6.6) and as a result clear dose-dependent contrast enhancements in R1 and R2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T1 and T2 MR images. PMID:26291827

  9. Application of time-resolved autofluorescence to label-free in vivo optical mapping of changes in tissue matrix and metabolism associated with myocardial infarction and heart failure

    PubMed Central

    Lagarto, Joo; Dyer, Benjamin T.; Talbot, Clifford; Sikkel, Markus B.; Peters, Nicholas S.; French, Paul M. W.; Lyon, Alexander R.; Dunsby, Chris

    2015-01-01

    We investigate the potential of an instrument combining time-resolved spectrofluorometry and diffuse reflectance spectroscopy to measure structural and metabolic changes in cardiac tissue in vivo in a 16 week post-myocardial infarction heart failure model in rats. In the scar region, we observed changes in the fluorescence signal that can be explained by increased collagen content, which is in good agreement with histology. In areas remote from the scar tissue, we measured changes in the fluorescence signal (p < 0.001) that cannot be explained by differences in collagen content and we attribute this to altered metabolism within the myocardium. A linear discriminant analysis algorithm was applied to the measurements to predict the tissue disease state. When we combine all measurements, our results reveal high diagnostic accuracy in the infarcted area (100%) and border zone (94.44%) as well as in remote regions from the scar (> 77%). Overall, our results demonstrate the potential of our instrument to characterize structural and metabolic changes in a failing heart in vivo without using exogenous labels. PMID:25780727

  10. Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

    NASA Astrophysics Data System (ADS)

    Tegafaw, Tirusew; Xu, Wenlong; Wasi Ahmad, Md; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

    2015-09-01

    A new type of dual-mode T1 and T2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd3+ (8S7/2) plays an important role in T1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy3+ (6H15/2) has the potential to be used in T2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy2O3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd3+ and Dy3+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T1 and T2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (davg = 1.0 nm) showed large r1 and r2 values (r2/r1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R1 and R2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T1 and T2 MR images.

  11. 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

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

    2009-09-01

    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

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

    PubMed Central

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

    2012-01-01

    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

  13. Biocompatible nanogenerators through high piezoelectric coefficient 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 nanowires for in-vivo applications.

    PubMed

    Yuan, Miaomiao; Cheng, Li; Xu, Qi; Wu, Weiwei; Bai, Suo; Gu, Long; Wang, Zhe; Lu, Jun; Li, Huanping; Qin, Yong; Jing, Tao; Wang, Zhong Lin

    2014-11-26

    Lead-free BZT-BCT (0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3) nanowires with a high piezoelectric coefficient are synthesized and nanogenerators (NGs) composed of them are successfully developed. The studied in vitro and in vivo biocompatibility of the NGs shows great potential for their application as in vivo power sources. PMID:25257019

  14. Regulation of cellular gas exchange, oxygen sensing, and metabolic control.

    PubMed

    Clanton, T L; Hogan, M C; Gladden, L B

    2013-07-01

    Cells must continuously monitor and couple their metabolic requirements for ATP utilization with their ability to take up O2 for mitochondrial respiration. When O2 uptake and delivery move out of homeostasis, cells have elaborate and diverse sensing and response systems to compensate. In this review, we explore the biophysics of O2 and gas diffusion in the cell, how intracellular O2 is regulated, how intracellular O2 levels are sensed and how sensing systems impact mitochondrial respiration and shifts in metabolic pathways. Particular attention is paid to how O2 affects the redox state of the cell, as well as the NO, H2S, and CO concentrations. We also explore how these agents can affect various aspects of gas exchange and activate acute signaling pathways that promote survival. Two kinds of challenges to gas exchange are also discussed in detail: when insufficient O2 is available for respiration (hypoxia) and when metabolic requirements test the limits of gas exchange (exercising skeletal muscle). This review also focuses on responses to acute hypoxia in the context of the original "unifying theory of hypoxia tolerance" as expressed by Hochachka and colleagues. It includes discourse on the regulation of mitochondrial electron transport, metabolic suppression, shifts in metabolic pathways, and recruitment of cell survival pathways preventing collapse of membrane potential and nuclear apoptosis. Regarding exercise, the issues discussed relate to the O2 sensitivity of metabolic rate, O2 kinetics in exercise, and influences of available O2 on glycolysis and lactate production. PMID:23897683

  15. Oxygen-sensing by arterial chemoreceptors: Mechanisms and medical translation.

    PubMed

    Lpez-Barneo, Jos; Ortega-Senz, Patricia; Gonzlez-Rodrguez, Patricia; Fernndez-Agera, M Carmen; Macas, David; Pardal, Ricardo; Gao, Lin

    2016-01-01

    Acute O2 sensing is necessary for the activation of cardiorespiratory reflexes (hyperventilation and sympathetic activation), which permit the survival of individuals under hypoxic environments (e.g. high altitude) or medical conditions presenting with reduced capacity for gas exchange between the lung alveoli and the blood. Changes in blood O2 tension are detected by the arterial chemoreceptors, in particular the carotid body (CB), which act in concert with the adrenal medulla (AM) to facilitate rapid adaptations to hypoxia. The field of arterial chemoreception has undergone a considerable expansion in recent years, with many of the fundamental observations made at the molecular and cellular levels serving to improve our understanding of the pathogenesis of numerous medical disorders, and even to propose advances in the treatment strategies. In this review, after a short historical preface, we describe the current model of chemosensory transduction based on the modulation of membrane K(+) channels by O2 in specialized chemoreceptor cells. Recent progress in elucidating the molecular mechanisms underlying the modulation of ion channels by O2 tension, which involves mitochondrial complex I, is also discussed. The discovery in the last few years of a specific population of neural crest-derived stem cells in the CB explains the reversible growth of this organ, an intriguing and unusual property of this type of neuronal tissue that contributes to acclimatization under chronic hypoxia. The essential homeostatic role of the CB-AM axis is clearly evident in newly generated mouse models that reach adulthood, albeit with CB and AM atrophy. These animals exhibit a marked intolerance to even mild hypoxia. CB inhibition or over-activation can have important medical consequences. Respiratory depression by general anesthetics or by opioid use is a common clinical condition that frequently causes death in susceptible individuals. An exaggerated sympathetic outflow due to over-activation of the CB-AM axis may contribute to the pathogenesis of several highly prevalent medical conditions, such as chronic heart failure, obstructive sleep apnea, obesity, metabolic syndrome, and diabetes. A detailed understanding of the molecular mechanisms underlying acute O2 sensing may help in the design of more efficient therapeutic approaches to combat these disorders. PMID:26709054

  16. A Pyrene@Micelle Sensor for Fluorescent Oxygen Sensing

    PubMed Central

    Yuan, Yan-xia; Peng, Hong-shang; Ping, Jian-tao; Wang, Xiao-hui; You, Fang-tian

    2015-01-01

    For most fluorescent oxygen sensors developed today, their fabrication process is either time-consuming or needs specialized knowledge. In this work, a robust fluorescent oxygen sensor is facilely constructed by dissolving pyrene molecules into CTAB aqueous solution. The as-prepared pyrene@micelle sensors have submicron-sized diameter, and the concentration of utilized pyrene can be reduced as low as 0.8?mM but still can exhibit dominant excimer emission. The excimer fluorescence is sensitive to dissolved oxygen in both intensity and lifetime, and the respective Stern-Volmer plot follows a nonlinear behavior justified by a two-site model. Because of the merits of large Stokes shift (~140?nm), easy fabrication, and robustness, the pyrene@micelle sensors are very attractive for practical determination of oxygen. PMID:26539471

  17. Carotid body oxygen sensing and adaptation to hypoxia.

    PubMed

    Lpez-Barneo, Jos; Macas, David; Platero-Luengo, Aida; Ortega-Senz, Patricia; Pardal, Ricardo

    2016-01-01

    The carotid body (CB) is the principal arterial chemoreceptor that mediates the hyperventilatory response to hypoxia. Our understanding of CB function and its role in disease mechanisms has progressed considerably in the last decades, particularly in recent years. The sensory elements of the CB are the neuron-like glomus cells, which contain numerous transmitters and form synapses with afferent sensory fibers. The activation of glomus cells under hypoxia mainly depends on the modulation of O2-sensitive K(+) channels which leads to cell depolarization and the opening of Ca(2+) channels. This model of sensory transduction operates in all mammalian species studied thus far, including man. However, the molecular mechanisms underlying the modulation of ion channel function by changes in the O2 level are as yet unknown. The CB plays a fundamental role in acclimatization to sustained hypoxia. Mice with CB atrophy or patients who have undergone CB resection due to surgical treatments show a marked intolerance to even mild hypoxia. CB growth under hypoxia is supported by the existence of a resident population of neural crest-derived stem cells of glia-like phenotype. These stem cells are not highly affected by exposure to low O2 tension; however, there are abundant synapse-like contacts between the glomus cells and stem cells (chemoproliferative synapses), which may be needed to trigger progenitor cell proliferation and differentiation under hypoxia. CB hypo- or hyper-activation may also contribute to the pathogenesis of several prevalent human diseases. PMID:26373853

  18. In Vivo and In Vitro Detection of Luminescent and Fluorescent Lactobacillus reuteri and Application of Red Fluorescent mCherry for Assessing Plasmid Persistence.

    PubMed

    Karimi, Shokoufeh; Ahl, David; Vågesjö, Evelina; Holm, Lena; Phillipson, Mia; Jonsson, Hans; Roos, Stefan

    2016-01-01

    Lactobacillus reuteri is a symbiont that inhabits the gastrointestinal (GI) tract of mammals, and several strains are used as probiotics. After introduction of probiotic strains in a complex ecosystem like the GI tract, keeping track of them is a challenge. The main objectives of this study were to introduce reporter proteins that would enable in vivo and in vitro detection of L. reuteri and increase knowledge about its interactions with the host. We describe for the first time cloning of codon-optimized reporter genes encoding click beetle red luciferase (CBRluc) and red fluorescent protein mCherry in L. reuteri strains ATCC PTA 6475 and R2LC. The plasmid persistence of mCherry-expressing lactobacilli was evaluated by both flow cytometry (FCM) and conventional plate count (PC), and the plasmid loss rates measured by FCM were lower overall than those determined by PC. Neutralization of pH and longer induction duration significantly improved the mCherry signal. The persistency, dose-dependent signal intensity and localization of the recombinant bacteria in the GI tract of mice were studied with an in vivo imaging system (IVIS), which allowed us to detect fluorescence from 6475-CBRluc-mCherry given at a dose of 1×1010 CFU and luminescence signals at doses ranging from 1×105 to 1×1010 CFU. Both 6475-CBRluc-mCherry and R2LC-CBRluc were localized in the colon 1 and 2 h after ingestion, but the majority of the latter were still found in the stomach, possibly reflecting niche specificity for R2LC. Finally, an in vitro experiment showed that mCherry-producing R2LC adhered efficiently to the intra cellular junctions of cultured IPEC-J2 cells. In conclusion, the two reporter genes CBRluc and mCherry were shown to be suitable markers for biophotonic imaging (BPI) of L. reuteri and may provide useful tools for future studies of in vivo and in vitro interactions between the bacteria and the host. PMID:27002525

  19. Clinical application of in vivo treatment delivery verification based on PET/CT imaging of positron activity induced at high energy photon therapy.

    PubMed

    Janek Strt, Sara; Andreassen, Bjrn; Jonsson, Cathrine; Noz, Marilyn E; Maguire, Gerald Q; Nfstadius, Peder; Nslund, Ingemar; Schoenahl, Frederic; Brahme, Anders

    2013-08-21

    The purpose of this study was to investigate in vivo verification of radiation treatment with high energy photon beams using PET/CT to image the induced positron activity. The measurements of the positron activation induced in a preoperative rectal cancer patient and a prostate cancer patient following 50 MV photon treatments are presented. A total dose of 5 and 8 Gy, respectively, were delivered to the tumors. Imaging was performed with a 64-slice PET/CT scanner for 30 min, starting 7 min after the end of the treatment. The CT volume from the PET/CT and the treatment planning CT were coregistered by matching anatomical reference points in the patient. The treatment delivery was imaged in vivo based on the distribution of the induced positron emitters produced by photonuclear reactions in tissue mapped on to the associated dose distribution of the treatment plan. The results showed that spatial distribution of induced activity in both patients agreed well with the delivered beam portals of the treatment plans in the entrance subcutaneous fat regions but less so in blood and oxygen rich soft tissues. For the preoperative rectal cancer patient however, a 2 (0.5) cm misalignment was observed in the cranial-caudal direction of the patient between the induced activity distribution and treatment plan, indicating a beam patient setup error. No misalignment of this kind was seen in the prostate cancer patient. However, due to a fast patient setup error in the PET/CT scanner a slight mis-position of the patient in the PET/CT was observed in all three planes, resulting in a deformed activity distribution compared to the treatment plan. The present study indicates that the induced positron emitters by high energy photon beams can be measured quite accurately using PET imaging of subcutaneous fat to allow portal verification of the delivered treatment beams. Measurement of the induced activity in the patient 7 min after receiving 5 Gy involved count rates which were about 20 times lower than that of a patient undergoing standard (18)F-FDG treatment. When using a combination of short lived nuclides such as (15)O (half-life: 2 min) and (11)C (half-life: 20 min) with low activity it is not optimal to use clinical reconstruction protocols. Thus, it might be desirable to further optimize reconstruction parameters as well as to address hardware improvements in realizing in vivo treatment verification with PET/CT in the future. A significant improvement with regard to (15)O imaging could also be expected by having the PET/CT unit located close to the radiation treatment room. PMID:23880661

  20. Clinical application of in vivo treatment delivery verification based on PET/CT imaging of positron activity induced at high energy photon therapy

    NASA Astrophysics Data System (ADS)

    Janek Strååt, Sara; Andreassen, Björn; Jonsson, Cathrine; Noz, Marilyn E.; Maguire, Gerald Q., Jr.; Näfstadius, Peder; Näslund, Ingemar; Schoenahl, Frederic; Brahme, Anders

    2013-08-01

    The purpose of this study was to investigate in vivo verification of radiation treatment with high energy photon beams using PET/CT to image the induced positron activity. The measurements of the positron activation induced in a preoperative rectal cancer patient and a prostate cancer patient following 50 MV photon treatments are presented. A total dose of 5 and 8 Gy, respectively, were delivered to the tumors. Imaging was performed with a 64-slice PET/CT scanner for 30 min, starting 7 min after the end of the treatment. The CT volume from the PET/CT and the treatment planning CT were coregistered by matching anatomical reference points in the patient. The treatment delivery was imaged in vivo based on the distribution of the induced positron emitters produced by photonuclear reactions in tissue mapped on to the associated dose distribution of the treatment plan. The results showed that spatial distribution of induced activity in both patients agreed well with the delivered beam portals of the treatment plans in the entrance subcutaneous fat regions but less so in blood and oxygen rich soft tissues. For the preoperative rectal cancer patient however, a 2 ± (0.5) cm misalignment was observed in the cranial-caudal direction of the patient between the induced activity distribution and treatment plan, indicating a beam patient setup error. No misalignment of this kind was seen in the prostate cancer patient. However, due to a fast patient setup error in the PET/CT scanner a slight mis-position of the patient in the PET/CT was observed in all three planes, resulting in a deformed activity distribution compared to the treatment plan. The present study indicates that the induced positron emitters by high energy photon beams can be measured quite accurately using PET imaging of subcutaneous fat to allow portal verification of the delivered treatment beams. Measurement of the induced activity in the patient 7 min after receiving 5 Gy involved count rates which were about 20 times lower than that of a patient undergoing standard 18F-FDG treatment. When using a combination of short lived nuclides such as 15O (half-life: 2 min) and 11C (half-life: 20 min) with low activity it is not optimal to use clinical reconstruction protocols. Thus, it might be desirable to further optimize reconstruction parameters as well as to address hardware improvements in realizing in vivo treatment verification with PET/CT in the future. A significant improvement with regard to 15O imaging could also be expected by having the PET/CT unit located close to the radiation treatment room.

  1. In Vivo and In Vitro Detection of Luminescent and Fluorescent Lactobacillus reuteri and Application of Red Fluorescent mCherry for Assessing Plasmid Persistence

    PubMed Central

    Karimi, Shokoufeh; Ahl, David; Vågesjö, Evelina; Holm, Lena; Phillipson, Mia; Jonsson, Hans; Roos, Stefan

    2016-01-01

    Lactobacillus reuteri is a symbiont that inhabits the gastrointestinal (GI) tract of mammals, and several strains are used as probiotics. After introduction of probiotic strains in a complex ecosystem like the GI tract, keeping track of them is a challenge. The main objectives of this study were to introduce reporter proteins that would enable in vivo and in vitro detection of L. reuteri and increase knowledge about its interactions with the host. We describe for the first time cloning of codon-optimized reporter genes encoding click beetle red luciferase (CBRluc) and red fluorescent protein mCherry in L. reuteri strains ATCC PTA 6475 and R2LC. The plasmid persistence of mCherry-expressing lactobacilli was evaluated by both flow cytometry (FCM) and conventional plate count (PC), and the plasmid loss rates measured by FCM were lower overall than those determined by PC. Neutralization of pH and longer induction duration significantly improved the mCherry signal. The persistency, dose-dependent signal intensity and localization of the recombinant bacteria in the GI tract of mice were studied with an in vivo imaging system (IVIS), which allowed us to detect fluorescence from 6475-CBRluc-mCherry given at a dose of 1×1010 CFU and luminescence signals at doses ranging from 1×105 to 1×1010 CFU. Both 6475-CBRluc-mCherry and R2LC-CBRluc were localized in the colon 1 and 2 h after ingestion, but the majority of the latter were still found in the stomach, possibly reflecting niche specificity for R2LC. Finally, an in vitro experiment showed that mCherry-producing R2LC adhered efficiently to the intra cellular junctions of cultured IPEC-J2 cells. In conclusion, the two reporter genes CBRluc and mCherry were shown to be suitable markers for biophotonic imaging (BPI) of L. reuteri and may provide useful tools for future studies of in vivo and in vitro interactions between the bacteria and the host. PMID:27002525

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

    PubMed Central

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

    2013-01-01

    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

  3. In vivo measurement of the shape of the tissue-refractive-index correlation function and its application to detection of colorectal field carcinogenesis.

    PubMed

    Gomes, Andrew J; Ruderman, Sarah; DelaCruz, Mart; Wali, Ramesh K; Roy, Hemant K; Backman, Vadim

    2012-04-01

    Polarization-gated spectroscopy is an established method to depth-selectively interrogate the structural properties of biological tissue. We employ this method in vivo in the azoxymethane (AOM)-treated rat model to monitor the morphological changes that occur in the field of a tumor during early carcinogenesis. The results demonstrate a statistically significant change in the shape of the refractive-index correlation function for AOM-treated rats versus saline-treated controls. Since refractive index is linearly proportional to mass density, these refractive-index changes can be directly linked to alterations in the spatial distribution patterns of macromolecular density. Furthermore, we found that alterations in the shape of the refractive-index correlation function shape were an indicator of both present and future risk of tumor development. These results suggest that noninvasive measurement of the shape of the refractive-index correlation function could be a promising marker of early cancer development. PMID:22559696

  4. 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

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

    2013-01-01

    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

  5. A Hybrid Peptide PTS that Facilitates Transmembrane Delivery and Its Application for the Rapid In vivo Imaging via Near-Infrared Fluorescence Imaging

    PubMed Central

    Yan, Xuejiao; Wu, Guoqiu; Qu, Qingrong; Fan, Xiaobo; Xu, Xudong; Liu, Naifeng

    2016-01-01

    Background and purpose: Intravital imaging provides invaluable readouts for clinical diagnoses and therapies and shows great potential in the design of individualized drug dosage regimes. Ts is a mammalian free cell membrane-penetrating peptide. This study aimed to introduce a novel approach to the design of a cancer-selective peptide on the basis of a membrane-penetrating peptide and to explore its potential as a carrier of medical substances. Experimental approach:Ts was linked with a αvβ3-binding peptide P1c to create a hybrid referred to as PTS. The hybrid was labeled with an FITC or Cy5.5 as an imaging indicator to evaluate its in vitro and in vivo bioactivity. Key results:Hemolysis tests proved that in comparison with Ts, PTS caused similar or even less leakage of human erythrocytes at concentrations of up to 1 mmol/L. Flow cytometry assay and confocal microscopy demonstrated the following. (1) P1c alone could target and mostly halt at the cancer cell membrane. (2) Ts alone could not bind to the membrane sufficiently. (3) P1c greatly enhanced the binding affinity of PTS with MDA-MB-231 breast cancer cells that upregulated αvβ3. (4) Ts conferred PTS with the ability to traverse a cell membrane and thus facilitate the transmembrane delivery of imaging probes. In vivo near-infrared fluorescence (NIRF) imaging demonstrated that the imaging probes were rapidly concentrated in a MDA-MB-231 tumor tissue within 1 h after intravenous injection. Conclusions and implications:PTS exhibited the capability of targeting specific tumors and greatly facilitating the transmembrane delivery of imaging probes. PMID:27014065

  6. Redox imaging of skeletal muscle using in vivo DNP-MRI and its application to an animal model of local inflammation.

    PubMed

    Eto, Hinako; Hyodo, Fuminori; Kosem, Nutavutt; Kobayashi, Ryoma; Yasukawa, Keiji; Nakao, Motonao; Kiniwa, Mamoru; Utsumi, Hideo

    2015-12-01

    Disorders of skeletal muscle are often associated with inflammation and alterations in redox status. A non-invasive technique that could localize and evaluate the severity of skeletal muscle inflammation based on its redox environment would be useful for disease identification and monitoring, and for the development of treatments; however, no such technique currently exists. We describe a method for redox imaging of skeletal muscle using dynamic nuclear polarization magnetic resonance imaging (DNP-MRI), and apply this method to an animal model of local inflammation. Female C57/BL6 mice received injections of 0.5% bupivacaine into their gastrocnemius muscles. Plasma biomarkers, myeloperoxidase activity, and histological sections were assessed at 4 and 24h after bupivacaine injection to measure the inflammatory response. In vivo DNP-MRI was performed with the nitroxyl radicals carbamoyl-PROXYL (cell permeable) and carboxy-PROXYL (cell impermeable) as molecular imaging probes at 4 and 24h after bupivacaine administration. The images obtained after carbamoyl-PROXYL administration were confirmed with the results of L-band EPR spectroscopy. The plasma biomarkers, myeloperoxidase activity, and histological findings indicated that bupivacaine injection caused acute muscle damage and inflammation. DNP-MRI images of mice treated with carbamoyl-PROXYL or carboxy-PROXYL at 4 and 24h after bupivacaine injection showed similar increases in image intensity and decay rate was significantly increased at 24h. In addition, reduction rates in individual mice at 4h and 24h showed faster trends with bupivacaine injection than in their contralateral sides by image-based analysis. These findings indicate that in vivo DNP-MRI with nitroxyl radicals can non-invasively detect changes in the focal redox status of muscle resulting from locally-induced inflammation. PMID:26505925

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

    PubMed

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

    2013-09-01

    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

  8. The Antisense RNA Approach: a New Application for In Vivo Investigation of the Stress Response of Oenococcus oeni, a Wine-Associated Lactic Acid Bacterium.

    PubMed

    Darsonval, Maud; Msadek, Tarek; Alexandre, Hervé; Grandvalet, Cosette

    2015-01-01

    Oenococcus oeni is a wine-associated lactic acid bacterium mostly responsible for malolactic fermentation in wine. In wine, O. oeni grows in an environment hostile to bacterial growth (low pH, low temperature, and ethanol) that induces stress response mechanisms. To survive, O. oeni is known to set up transitional stress response mechanisms through the synthesis of heat stress proteins (HSPs) encoded by the hsp genes, notably a unique small HSP named Lo18. Despite the availability of the genome sequence, characterization of O. oeni genes is limited, and little is known about the in vivo role of Lo18. Due to the lack of genetic tools for O. oeni, an efficient expression vector in O. oeni is still lacking, and deletion or inactivation of the hsp18 gene is not presently practicable. As an alternative approach, with the goal of understanding the biological function of the O. oeni hsp18 gene in vivo, we have developed an expression vector to produce antisense RNA targeting of hsp18 mRNA. Recombinant strains were exposed to multiple stresses inducing hsp18 gene expression: heat shock and acid shock. We showed that antisense attenuation of hsp18 affects O. oeni survival under stress conditions. These results confirm the involvement of Lo18 in heat and acid tolerance of O. oeni. Results of anisotropy experiments also confirm a membrane-protective role for Lo18, as previous observations had already suggested. This study describes a new, efficient tool to demonstrate the use of antisense technology for modulating gene expression in O. oeni. PMID:26452552

  9. The design of a double-tuned two-port surface resonator and its application to in vivo Hydrogen- and Sodium-MRI

    NASA Astrophysics Data System (ADS)

    Wetterling, Friedrich; Hgler, Miroslav; Molkenthin, Ute; Junge, Sven; Gallagher, Lindsay; Mhairi Macrae, I.; Fagan, Andrew J.

    2012-04-01

    The design and construction of a two-port surface transceiver resonator for both 1H- and 23Na-MRI in the rodent brain at 7 T is described. Double-tuned resonators are required for accurately co-registering multi-nuclei data sets, especially when the time courses of 1H and 23Na signals are of interest as, for instance, when investigating the pathological progression of ischaemic stroke tissue in vivo. In the current study, a single-element two-port surface resonator was developed wherein both frequency components were measured with the same detector element but with each frequency signal routed along different output channels. This was achieved by using the null spot technique, allowing for optimal variable tuning and matching of each channel in situ within the MRI scanner. The 23Na signal to noise ratio, measured in the ventricles of the rat brain, was increased by a factor of four compared to recent state-of-the-art rat brain studies reported in the literature. The resonator's performance was demonstrated in an in vivo rodent stroke model, where regional variations in 1H apparent diffusion coefficient maps and the 23Na signal were recorded in an interleaved fashion as a function of time in the acute phase of the stroke without having to exchange, re-adjust, or re-connect resonators between scans. Using the practical construction steps described in this paper, this coil design can be easily adapted for MRI of other X-nuclei, such as 17O, 13C, 39K, and 43Ca at various field strengths.

  10. Terahertz pulsed imaging in vivo

    NASA Astrophysics Data System (ADS)

    Pickwell-MacPherson, E.

    2011-03-01

    Terahertz (1012 Hz) pulsed imaging is a totally non-destructive and non-ionising imaging modality and thus potential applications in medicine are being investigated. In this paper we present results using our hand-held terahertz probe that has been designed for in vivo use. In particular, we use the terahertz probe to perform reflection geometry in vivo measurements of human skin. The hand-held terahertz probe gives more flexibility than a typical flat-bed imaging system, but it also results in noisier data and requires existing processing methods to be improved. We describe the requirements and limitations of system geometry, data acquisition rate, image resolution and penetration depth and explain how various factors are dependent on each other. We show how some of the physical limitations can be overcome using novel data processing methods.

  11. 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)

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

    2014-07-01

    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

  12. Tropisms of AAV for Subretinal Delivery to the Neonatal Mouse Retina and Its Application for In Vivo Rescue of Developmental Photoreceptor Disorders

    PubMed Central

    Watanabe, Satoshi; Sanuki, Rikako; Ueno, Shinji; Koyasu, Toshiyuki; Hasegawa, Toshiaki; Furukawa, Takahisa

    2013-01-01

    Background Adeno-associated virus (AAV) is well established as a vehicle for in vivo gene transfer into the mammalian retina. This virus is promising not only for gene therapy of retinal diseases, but also for in vivo functional analysis of retinal genes. Previous reports have shown that AAV can infect various cell types in the developing mouse retina. However, AAV tropism in the developing retina has not yet been examined in detail. Methodology/Principal Findings We subretinally delivered seven AAV serotypes (AAV2/1, 2/2, 2/5, 2/8, 2/9, 2/10, and 2/11) of AAV-CAG-mCherry into P0 mouse retinas, and quantitatively evaluated the tropisms of each serotype by its infecting degree in retinal cells. After subretinal injection of AAV into postnatal day 0 (P0) mouse retinas, various retinal cell types were efficiently transduced with different AAVs. Photoreceptor cells were efficiently transduced with AAV2/5. Retinal cells, except for bipolar and Müller glial cells, were efficiently transduced with AAV2/9. Horizontal and/or ganglion cells were efficiently transduced with AAV2/1, AAV2/2, AAV2/8, AAV2/9 and AAV2/10. To confirm the usefulness of AAV-mediated gene transfer into the P0 mouse retina, we performed AAV-mediated rescue of the Cone-rod homeobox gene knockout (Crx KO) mouse, which exhibits an outer segment formation defect, flat electroretinogram (ERG) responses, and photoreceptor degeneration. We injected an AAV expressing Crx under the control of the Crx 2kb promoter into the neonatal Crx KO retina. We showed that AAV mediated-Crx expression significantly decreased the abnormalities of the Crx KO retina. Conclusion/Significance In the current study, we report suitable AAV tropisms for delivery into the developing mouse retina. Using AAV2/5 in photoreceptor cells, we demonstrated the possibility of gene replacement for the developmental disorder and subsequent degeneration of retinal photoreceptors caused by the absence of Crx. PMID:23335994

  13. Umbilical cord mesenchymal stem cells labeled with multimodal iron oxide nanoparticles with fluorescent and magnetic properties: application for in vivo cell tracking.

    PubMed

    Sibov, Tatiana T; Pavon, Lorena F; Miyaki, Liza A; Mamani, Javier B; Nucci, Leopoldo P; Alvarim, Larissa T; Silveira, Paulo H; Marti, Luciana C; Gamarra, Lf

    2014-01-01

    Here we describe multimodal iron oxide nanoparticles conjugated to Rhodamine-B (MION-Rh), their stability in culture medium, and subsequent validation of an in vitro protocol to label mesenchymal stem cells from umbilical cord blood (UC-MSC) with MION-Rh. These cells showed robust labeling in vitro without impairment of their functional properties, the viability of which were evaluated by proliferation kinetic and ultrastructural analyzes. Thus, labeled cells were infused into striatum of adult male rats of animal model that mimic late onset of Parkinson's disease and, after 15 days, it was observed that cells migrated along the medial forebrain bundle to the substantia nigra as hypointense spots in T2 magnetic resonance imaging. These data were supported by short-term magnetic resonance imaging. Studies were performed in vivo, which showed that about 5 × 10(5) cells could be efficiently detected in the short term following infusion. Our results indicate that these labeled cells can be efficiently tracked in a neurodegenerative disease model. PMID:24531365

  14. 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

    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

    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

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

    PubMed

    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

    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

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

    PubMed Central

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

    2010-01-01

    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

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

    PubMed

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

    2014-12-10

    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 2μgmL(-1) and the quantification limit (S/N=10) was 6μgmL(-1). Coefficients of linear regression were higher than 0.99 for concentrations between 6.25 and 200μgmL(-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. PMID:24992924

  18. Cultivation of Keratinocytes and Fibroblasts in a Three-Dimensional Bovine Collagen-Elastin Matrix (Matriderm) and Application for Full Thickness Wound Coverage in Vivo

    PubMed Central

    Killat, Jasper; Reimers, Kerstin; Choi, Claudia Y.; Jahn, Sabrina; Vogt, Peter M.; Radtke, Christine

    2013-01-01

    New skin substitutes for burn medicine or reconstructive surgery pose an important issue in plastic surgery. Matriderm is a clinically approved three-dimensional bovine collagen-elastin matrix which is already used as a dermal substitute of full thickness burn wounds. The drawback of an avital matrix is the limited integration in full thickness skin defects, depending on the defect size. To further optimize this process, Matriderm has also been studied as a matrix for tissue engineering of skin albeit long-term cultivation of the matrix with cells has been difficult. Cells have generally been seeded onto the matrix with high cell loss and minimal time-consuming migration. Here we developed a cell seeded skin equivalent after microtransfer of cells directly into the matrix. First, cells were cultured, and microinjected into Matriderm. Then, cell viability in the matrix was determined by histology in vitro. As a next step, the skin substitute was applied in vivo into a full thickness rodent wound model. The wound coverage and healing was observed over a period of two weeks followed by histological examination assessing cell viability, proliferation and integration into the host. Viable and proliferating cells could be found throughout the entire matrix. The presented skin substitute resembles healthy skin in morphology and integrity. Based on this study, future investigations are planned to examine behaviour of epidermal stem cells injected into a collagen-elastin matrix under the aspects of establishment of stem cell niches and differentiation. PMID:23852021

  19. Frog volatile compounds: application of in vivo SPME for the characterization of the odorous secretions from two species of Hypsiboas treefrogs.

    PubMed

    Brunetti, Andrés E; Merib, Josias; Carasek, Eduardo; Caramão, Elina B; Barbará, Janaina; Zini, Claudia A; Faivovich, Julián

    2015-04-01

    A novel in vivo design was used in combination with solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) to characterize the volatile compounds from the skin secretion of two species of tree frogs. Conventional SPME-GC/MS also was used for the analysis of volatiles present in skin samples and for the analysis of volatiles present in the diet and terraria. In total, 40 and 37 compounds were identified in the secretion of Hypsiboas pulchellus and H. riojanus, respectively, of which, 35 were common to both species. Aliphatic aldehydes, a low molecular weight alkadiene, an aromatic alcohol, and other aromatics, ketones, a methoxy pyrazine, sulfur containing compounds, and hemiterpenes are reported here for the first time in anurans. Most of the aliphatic compounds seem to be biosynthesized by the frogs following different metabolic pathways, whereas aromatics and monoterpenes are most likely sequestered from environmental sources. The characteristic smell of the secretion of H. pulchellus described by herpetologists as skunk-like or herbaceous is explained by a complex blend of different odoriferous components. The possible role of the volatiles found in H. pulchellus and H. riojanus is discussed in the context of previous hypotheses about the biological function of volatile secretions in frogs (e.g., sex pheromones, defense secretions against predators, mosquito repellents). PMID:25912225

  20. Umbilical cord mesenchymal stem cells labeled with multimodal iron oxide nanoparticles with fluorescent and magnetic properties: application for in vivo cell tracking

    PubMed Central

    Sibov, Tatiana T; Pavon, Lorena F; Miyaki, Liza A; Mamani, Javier B; Nucci, Leopoldo P; Alvarim, Larissa T; Silveira, Paulo H; Marti, Luciana C; Gamarra, LF

    2014-01-01

    Here we describe multimodal iron oxide nanoparticles conjugated to Rhodamine-B (MION-Rh), their stability in culture medium, and subsequent validation of an in vitro protocol to label mesenchymal stem cells from umbilical cord blood (UC-MSC) with MION-Rh. These cells showed robust labeling in vitro without impairment of their functional properties, the viability of which were evaluated by proliferation kinetic and ultrastructural analyzes. Thus, labeled cells were infused into striatum of adult male rats of animal model that mimic late onset of Parkinsons disease and, after 15 days, it was observed that cells migrated along the medial forebrain bundle to the substantia nigra as hypointense spots in T2 magnetic resonance imaging. These data were supported by short-term magnetic resonance imaging. Studies were performed in vivo, which showed that about 5 105 cells could be efficiently detected in the short term following infusion. Our results indicate that these labeled cells can be efficiently tracked in a neurodegenerative disease model. PMID:24531365

  1. Very small embryonic-like stem-cell optimization of isolation protocols: an update of molecular signatures and a review of current in vivo applications

    PubMed Central

    Shin, Dong-Myung; Suszynska, Malwina; Mierzejewska, Kasia; Ratajczak, Janina; Ratajczak, Mariusz Z

    2013-01-01

    As the theory of stem cell plasticity was first proposed, we have explored an alternative hypothesis for this phenomenon: namely that adult bone marrow (BM) and umbilical cord blood (UCB) contain more developmentally primitive cells than hematopoietic stem cells (HSCs). In support of this notion, using multiparameter sorting we were able to isolate small Sca1+Lin−CD45− cells and CD133+Lin−CD45− cells from murine BM and human UCB, respectively, which were further enriched for the detection of various early developmental markers such as the SSEA antigen on the surface and the Oct4 and Nanog transcription factors in the nucleus. Similar populations of cells have been found in various organs by our team and others, including the heart, brain and gonads. Owing to their primitive cellular features, such as the high nuclear/cytoplasm ratio and the presence of euchromatin, they are called very small embryonic-like stem cells (VSELs). In the appropriate in vivo models, VSELs differentiate into long-term repopulating HSCs, mesenchymal stem cells (MSCs), lung epithelial cells, cardiomyocytes and gametes. In this review, we discuss the most recent data from our laboratory and other groups regarding the optimal isolation procedures and describe the updated molecular characteristics of VSELs. PMID:24232255

  2. Determination of 3-methoxysalicylamine levels in mouse plasma and tissue by liquid chromatography-tandem mass spectrometry: application to in vivo pharmacokinetics studies.

    PubMed

    Zagol-Ikapitte, Irene; Amarnath, Venkataraman; Jadhav, Satyawan; Oates, John A; Boutaud, Olivier

    2011-05-01

    We report the development of a sensitive liquid chromatography-tandem mass spectrometric assay to quantitate 3-methoxysalicylamine (3-MoSA) in biological samples. Derivatization with 1,1'-thiocarbonyldiimidazole followed by C(18) reverse-phase chromatography allowed the detection of both analyte and internal standard (hexylsalicylamine) using electrospray ionization and selected reaction monitoring (SRM) in positive ion mode. We monitored the transitions from m/z 196.7 to 65.1 and from m/z 250.1 to 77.1 for 3-MoSA and HxSA, respectively. The method is validated with respect to linearity (r(2)=0.995), precision (<17% RSD), recovery (100% for 3-MoSA and HxSA), and stability (77% after storage up to 7 month at -80C). The LOD and LOQ were 16.12 and 48.87 ?g/l, respectively and the LLOQ of 1 pg/ml. In addition, we used this assay to analyze the pharmacokinetics of 3-MoSA in mouse plasma and tissues following both intraperitoneal and oral administration, providing new information regarding the distribution of this compound in vivo. PMID:21489890

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

    PubMed

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

    2010-06-01

    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

  4. In vivo biotinylated recombinant antibodies: construction, characterization, and application of a bifunctional Fab-BCCP fusion protein produced in Escherichia coli.

    PubMed

    Weiss, E; Chatellier, J; Orfanoudakis, G

    1994-10-01

    We describe a novel vector system suitable for the efficient preparation of in vivo biotinylated antibody Fab fragments in Escherichia coli. The previously described pGE20 vector used for the functional expression of truncated heavy (Fd) and light (L) chains of Fab into the bacterial culture medium was modified by inserting the C-terminal 101-amino-acid polypeptide of the biotin carboxyl carrier protein subunit of E. coli acetyl-CoA carboxylase (BCCP*). The secreted Fd-BCCP* fusion and L chain proteins were found to be disulfide linked and Fab-BCCP* complexes of an IgG1 antibody (Mab4) to human tumor necrosis factor alpha (TNF) were shown to retain both antigen and streptavidin-binding activities. The capacity of the Fab4 linked to BCCP* to bind TNF was identical to that observed with unmodified Fab4. Up to 15% of the expressed hybrids were able to interact with streptavidin when exogeneous d-biotin was added into the bacterial culture medium. The Fab4-BCCP* molecules were found to be more efficient than Fab4 linked to an engineered streptavidin-affinity tag for the detection of antigen on solid phase. In addition, we show here that the bacterially expressed Fab4-BCCP* complexes, adsorbed to streptavidin-agarose beads, can be used for the one-step purification of recombinant TNF by immunoaffinity chromatography. PMID:7827508

  5. Novel estimation of the electrical bioimpedance using the local polynomial method. Application to in vivo real-time myocardium tissue impedance characterization during the cardiac cycle.

    PubMed

    Sanchez, Benjamin; Schoukens, Johan; Bragos, Ramon; Vandersteen, Gerd

    2011-12-01

    Classical measurements of myocardium tissue electrical impedance for characterizing the morphology of myocardium cells, as well as cell membranes integrity and intra/extra cellular spaces, are based on the frequency-sweep electrical impedance spectroscopy (EIS) technique. In contrast to the frequency-sweep EIS approach, measuring with broadband signals, i.e., multisine excitations, enables to collect, simultaneously, multiple myocardium tissue impedance data in a short measuring time. However, reducing the measuring time makes the measurements to be prone to the influence of the transients introduced by noise and the dynamic time-varying properties of tissue. This paper presents a novel approach for the impedance-frequency-response estimation based on the local polynomial method (LPM). The fast LPM version presented rejects the leakage error's influence on the impedance frequency response when measuring electrical bioimpedance in a short time. The theory is supported by a set of validation measurements. Novel preliminary experimental results obtained from real-time in vivo healthy myocardium tissue impedance characterization within the cardiac cycle using multisine excitation are reported. PMID:21878408

  6. 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

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

    2014-01-01

    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

  7. Dissolution DNP for in vivo preclinical studies.

    PubMed

    Comment, Arnaud

    2016-03-01

    The tremendous polarization enhancement afforded by dissolution dynamic nuclear polarization (DNP) can be taken advantage of to perform preclinical in vivo molecular and metabolic imaging. Following the injection of molecules that are hyperpolarized via dissolution DNP, real-time measurements of their biodistribution and metabolic conversion can be recorded. This technology therefore provides a unique and invaluable tool for probing cellular metabolism in vivo in animal models in a noninvasive manner. It gives the opportunity to follow and evaluate disease progression and treatment response without requiring ex vivo destructive tissue assays. Although its considerable potential has now been widely recognized, hyperpolarized magnetic resonance by dissolution DNP remains a challenging method to implement for routine in vivo preclinical measurements. The aim of this article is to provide an overview of the current state-of-the-art technology for preclinical applications and the challenges that need to be addressed to promote it and allow its wider dissemination in the near future. PMID:26920829

  8. Dissolution DNP for in vivo preclinical studies

    NASA Astrophysics Data System (ADS)

    Comment, Arnaud

    2016-03-01

    The tremendous polarization enhancement afforded by dissolution dynamic nuclear polarization (DNP) can be taken advantage of to perform preclinical in vivo molecular and metabolic imaging. Following the injection of molecules that are hyperpolarized via dissolution DNP, real-time measurements of their biodistribution and metabolic conversion can be recorded. This technology therefore provides a unique and invaluable tool for probing cellular metabolism in vivo in animal models in a noninvasive manner. It gives the opportunity to follow and evaluate disease progression and treatment response without requiring ex vivo destructive tissue assays. Although its considerable potential has now been widely recognized, hyperpolarized magnetic resonance by dissolution DNP remains a challenging method to implement for routine in vivo preclinical measurements. The aim of this article is to provide an overview of the current state-of-the-art technology for preclinical applications and the challenges that need to be addressed to promote it and allow its wider dissemination in the near future.

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

    PubMed Central

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

    2014-01-01

    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

  10. Predicting surface strains at the human distal radius during an in vivo loading task--finite element model validation and application.

    PubMed

    Bhatia, Varun A; Edwards, W Brent; Troy, Karen L

    2014-08-22

    Bone strains resulting from physical activity are thought to be a primary driver of bone adaptation, but cannot be directly noninvasively measured. Because bone adapts nonuniformly, physical activity may make an important independent structural contribution to bone strength that is independent of bone mass and density. Our objective was to create and validate methods for subject-specific finite element (FE) model generation that would accurately predict the surface strains experienced by the distal radius during an in vivo loading task, and to apply these methods to a group of 23 women aged 23-35 to examine variations in strain, bone mass and density, and physical activity. Four cadaveric specimens were experimentally tested and specimen-specific FE models were developed to accurately predict periosteal surface strains (root mean square error=16.3%). In the living subjects, when 300 N load was simulated, mean strains were significantly inversely correlated with BMC (r=-0.893), BMD (r=-0.892) and physical activity level (r=-0.470). Although the group of subjects was relatively homogenous, BMD varied by two-fold (range: 0.19-0.40 g/cm(3)) and mean energy-equivalent strain varied by almost six-fold (range: 226.79-1328.41 με) with a simulated 300 N load. In summary, we have validated methods for estimating surface strains in the distal radius that occur while leaning onto the palm of the hand. In our subjects, strain varied widely across individuals, and was inversely related to bone parameters that can be measured using clinical CT, and inversely related to physical activity history. PMID:24882740

  11. In vitro and in vivo experiments with iron oxide nanoparticles functionalized with DEXTRAN or polyethylene glycol for medical applications: magnetic targeting.

    PubMed

    Mojica Pisciotti, M L; Lima, E; Vasquez Mansilla, M; Tognoli, V E; Troiani, H E; Pasa, A A; Creczynski-Pasa, T B; Silva, A H; Gurman, P; Colombo, L; Goya, G F; Lamagna, A; Zysler, R D

    2014-05-01

    In this research work, DEXTRAN- and polyethylene glycol (PEG)-coated iron-oxide superparamagnetic nanoparticles were synthetized and their cytotoxicity and biodistribution assessed. Well-crystalline hydrophobic Fe3 O4 SPIONs were formed by a thermal decomposition process with d = 18 nm and ? = 2 nm; finally, the character of SPIONs was changed to hydrophilic by a post-synthesis procedure with the functionalization of the SPIONs with PEG or DEXTRAN. The nanoparticles present high saturation magnetization and superparamagnetic behavior at room temperature, and the hydrodynamic diameters of DEXTRAN- and PEG-coated SPIONs were measured as 170 and 120 nm, respectively. PEG- and DEXTRAN-coated SPIONs have a Specific Power Absorption SPA of 320 and 400 W/g, respectively, in an ac magnetic field with amplitude of 13 kA/m and frequency of 256 kHz. In vitro studies using VERO and MDCK cell lineages were performed to study the cytotoxicity and cell uptake of the SPIONs. For both cell lineages, PEG- and DEXTRAN-coated nanoparticles presented high cell viability for concentrations as high as 200 ?g/mL. In vivo studies were conducted using BALB/c mice inoculating the SPIONs intravenously and exposing them to the presence of an external magnet located over the tumour. It was observed that the amount of PEG-coated SPIONs in the tumor increased by up to 160% when using the external permanent magnetic as opposed to those animals that were not exposed to the external magnetic field. PMID:24458920

  12. Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation.

    PubMed

    Fu, Qiang; Rahaman, Mohamed N; Bal, B Sonny; Bonewald, Lynda F; Kuroki, Keiichi; Brown, Roger F

    2010-10-01

    In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects. PMID:20540099

  13. Characterization of Fast-Scan Cyclic Voltammetric Electrodes Using Paraffin as an Effective Sealant with In Vitro and In Vivo Applications.

    PubMed

    Ramsson, Eric S; Cholger, Daniel; Dionise, Albert; Poirier, Nicholas; Andrus, Avery; Curtiss, Randi

    2015-01-01

    Fast-scan cyclic voltammetry (FSCV) is a powerful technique for measuring sub-second changes in neurotransmitter levels. A great time-limiting factor in the use of FSCV is the production of high-quality recording electrodes; common recording electrodes consist of cylindrical carbon fiber encased in borosilicate glass. When the borosilicate is heated and pulled, the molten glass ideally forms a tight seal around the carbon fiber cylinder. It is often difficult, however, to guarantee a perfect seal between the glass and carbon. Indeed, much of the time spent creating electrodes is in an effort to find a good seal. Even though epoxy resins can be useful in this regard, they are irreversible (seals are permanent), wasteful (epoxy cannot be reused once hardener is added), hazardous (hardeners are often caustic), and require curing. Herein we characterize paraffin as an electrode sealant for FSCV microelectrodes. Paraffin boasts the advantages of near-immediate curing times, simplicity in use, long shelf-life and stable waterproof seals capable of withstanding extended cycling. Borosilicate electrode tips were left intact or broken and dipped in paraffin embedding wax. Excess wax was removed from the carbon surface with xyelenes or by repeated cycling at an extended waveform (-0.4 to 1.4V, 400 V/s, 60 Hz). Then, the waveform was switched to a standard waveform (-0.4 to 1.3V, 400 V/s, 10 Hz) and cycled until stable. Wax-sealing does not inhibit electrode sensitivity, as electrodes detected linear changes in dopamine before and after wax (then xylenes) exposure. Paraffin seals are intact after 11 days of implantation in the mouse, and still capable of measuring transient changes in in vivo dopamine. From this it is clear that paraffin wax is an effective sealant for FSCV electrodes that provides a convenient substitute to epoxy sealants. PMID:26505195

  14. Inhibition of hen brain acetylcholinesterase and neurotoxic esterase by chlorpyrifos in vivo and kinetics of inhibition by chlorpyrifos oxon in vitro: application to assessment of neuropathic risk.

    PubMed

    Richardson, R J; Moore, T B; Kayyali, U S; Fowke, J H; Randall, J C

    1993-04-01

    Chlorpyrifos (CPS; O,O-diethyl 3,5,6-trichloro-2-pyridyl phosphorothionate; Dursban) is a widely used broad-spectrum organophosphorus (OP) insecticide. Because some OP compounds can cause a sensory-motor distal axonopathy called OP compound-induced delayed neurotoxicity (OPIDN), CPS has been evaluated for this paralytic effect. Early studies of the neurotoxicity of CPS in young and adult hens reported reversible leg weakness but failed to detect OPIDN. More recently, a human case of mild OPIDN was reported to result from ingestion of a massive dose (about 300 mg/kg) in a suicide attempt. Subsequent experiments in adult hens (the currently accepted animal model of choice for studies of OPIDN) showed that doses of CPS in excess of the LD50 in atropine-treated animals inhibited brain neurotoxic esterase (NTE) and produced mild to moderate ataxia. Considering the extensive use of CPS and its demonstrated potential for causing OPIDN at supralethal doses, additional data are needed to enable quantitative estimates to be made of the neuropathic risk of this compound. Previous work has shown that the ability of OP insecticides to cause acute cholinergic toxicity versus OPIDN can be predicted from their relative tendency to inhibit the intended target, acetylcholinesterase (AChE), versus the putative neuropathic target, NTE, in brain tissue. The present study was designed to clarify the magnitude of neuropathic risk associated with CPS exposures by measuring hen brain AChE and NTE inhibition following dosing in vivo and determining the bimolecular rate constant of inhibition (ki) for each enzyme by the active metabolite, CPS oxon (CPO), in vitro.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7684990

  15. Characterization of Fast-Scan Cyclic Voltammetric Electrodes Using Paraffin as an Effective Sealant with In Vitro and In Vivo Applications

    PubMed Central

    Ramsson, Eric S.; Cholger, Daniel; Dionise, Albert; Poirier, Nicholas; Andrus, Avery; Curtiss, Randi

    2015-01-01

    Fast-scan cyclic voltammetry (FSCV) is a powerful technique for measuring sub-second changes in neurotransmitter levels. A great time-limiting factor in the use of FSCV is the production of high-quality recording electrodes; common recording electrodes consist of cylindrical carbon fiber encased in borosilicate glass. When the borosilicate is heated and pulled, the molten glass ideally forms a tight seal around the carbon fiber cylinder. It is often difficult, however, to guarantee a perfect seal between the glass and carbon. Indeed, much of the time spent creating electrodes is in an effort to find a good seal. Even though epoxy resins can be useful in this regard, they are irreversible (seals are permanent), wasteful (epoxy cannot be reused once hardener is added), hazardous (hardeners are often caustic), and require curing. Herein we characterize paraffin as an electrode sealant for FSCV microelectrodes. Paraffin boasts the advantages of near-immediate curing times, simplicity in use, long shelf-life and stable waterproof seals capable of withstanding extended cycling. Borosilicate electrode tips were left intact or broken and dipped in paraffin embedding wax. Excess wax was removed from the carbon surface with xyelenes or by repeated cycling at an extended waveform (-0.4 to 1.4V, 400 V/s, 60 Hz). Then, the waveform was switched to a standard waveform (-0.4 to 1.3V, 400 V/s, 10 Hz) and cycled until stable. Wax-sealing does not inhibit electrode sensitivity, as electrodes detected linear changes in dopamine before and after wax (then xylenes) exposure. Paraffin seals are intact after 11 days of implantation in the mouse, and still capable of measuring transient changes in in vivo dopamine. From this it is clear that paraffin wax is an effective sealant for FSCV electrodes that provides a convenient substitute to epoxy sealants. PMID:26505195

  16. EDITORIAL: Nanotechnology in vivo Nanotechnology in vivo

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2010-04-01

    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 nanobubbles have either been slow or problematic due to the resulting development of cardiac dimension reduction, hypotension and tachycardia. Xing and colleagues have now demonstrated the use of polyoxyethylene 40 stearate, which is known to be biocompatible, degradable and non-toxic, as an alternative surfactant for generating nanobubbles. In the early 1980s scanning probe micrographs of nanosized features unleashed the power of imaging to push forward the science of structures and mechanisms at the nanoscale. The continued development of new and increasingly sophisticated nanoparticles and systems looks set to empower medicine in the same way, providing further means to exploit the mechanistic nature of biological organisms for better health and longevity. References [1] Leon R, Petroff P M, Leonard D and Fafard S 1995 Science 267 1966-8 [2] Nie Q, Tan W B and Zhang Y 2006 Nanotechnology 17 140-4 [3] Li L, Chen D, Zhang Y, Deng Z, Ren X, Meng X, Tang F, Ren J and Zhang L 2007 Nanotechnology 18 405102 [4] Fujioka K et al 2008 Nanotechnology 19 415102 [5] Shinoda K, Yangisawa S, Sato K amd Hirakuri K 2006 J. Cryst. Growth 288 84-6 [6] Manzoor K, Johny S, Thomas D, Setua S, Menon D and Nair S 2009 Nanotechnology 20 065102 [7] Hu R, Yong K-T, Roy I, Ding H, Law W-C, Cai H, Zhang X, Vathy L A, Bergey E J and Prasad P N 2010 Nanotechnology 21 145105 [8] Xing, Z, Ke H, Wang J, Zhao B, Yue X, Dai Z and Liu J 2010 Nanotechnology 21 145607

  17. New applications boost VCSEL quantities: recent developments at Philips

    NASA Astrophysics Data System (ADS)

    Grabherr, Martin

    2015-03-01

    Besides the mature and steadily growing datacom market for which VCSELs are key components in Transceivers, Active Optical Cables (AOC), Mid Board Optical Modules (MBOM) or Embedded Optical Modules (EOM), VCSELs have proven to be key components also for other volume applications. Laser mice emerged 2004, just after the burst of the dotcom bubble and the related downturn in the Datacom industry, and dominated the shipped quantities for some years, accompanied by various smaller applications like atomic clock, oxygen sensing, encoders, and many more. Over the past years, two other major applications came into focus: optical interconnects in high performance computers or datacenters and smart sensors for mobile devices. In addition, VCSELs are penetrating into more and more power applications, primarily for illumination or IR heating. We present recent developments in technology, products, and addressed market segments that will have a major impact on the VCSEL industry.

  18. Quantitative determination of zolmitriptan in rat blood and cerebrospinal fluid by reversed phase HPLC-ESI-MS/MS analysis: application to in vivo preclinical pharmacokinetic study.

    PubMed

    Dalpiaz, Alessandro; Marchetti, Nicola; Cavazzini, Alberto; Pasti, Luisa; Velaga, Sitaram; Gavini, Elisabetta; Beggiato, Sarah; Ferraro, Luca

    2012-07-15

    A fast HPLC-ESI-MS/MS method has been developed and validated for the quantification of the potent and selective antimigraine zolmitriptan in rat blood and cerebrospinal fluid (CSF). The assay has been then applied for in vivo preclinical studies. The analytical determination has been used to obtain pharmacokinetics of zolmitriptan in the two biological matrices after its intravenous or nasal administration. Liquid-liquid extraction of zolmitriptan was performed from 100 ?L rat blood samples in the presence of N(6)-cyclopentyladenosine (internal standard) with the employment of ethyl acetate. Calibration standards were prepared by using blood matrix and following the same liquid-liquid extraction procedure. CSF samples were analyzed without any pre-treatment steps and by using an external calibration method in pure water matrix. Chromatographic separation was performed under reversed phase and a gradient elution condition on a C18 packed column (100 2.0 mm, 2.5 ?m particles diameter). The mobile phase was a mixture between acetonitrile, water and formic acid (0.1% v/v). The applied HPLC-MS/MS method allowed low limits of detection, as calculated from calibration curves, of 6.6 and 24.4 ng/mL for water matrix and rat blood extracts, respectively. Linearity of the calibration curves was established up to 5 ?M (1.44 ?g/mL), as well as good assay accuracy. The intravenous infusion of 20 ?g zolmitriptan to male Sprague-Dawley rats produced blood concentrations ranging from 9.40.7 to 1.240.07 ?g/mL within 10 h, with a terminal half-life of 3.40.2h. The nasal administration of a water suspension of 20 ?g zolmitriptan produced blood concentrations ranging from 2.920.21 to 0.850.07 ?g/mL within 6h. One hour after zolmitriptan intravenous infusion or nasal administration, its CSF concentrations were 0.05390.0016 and 0.04530.0012 ?g/mL, respectively. This study determined the suitability of the herein proposed method to investigate the pharmacokinetics of zolmitriptan after its administration by means of novel formulations and, hence, to evaluate the efficacy of innovative nose-to-brain drug delivery in preclinical studies. PMID:22743338

  19. The application of the linear quadratic model to compensate the effects of prolonged fraction delivery time on a Balb/C breast adenocarcinoma tumor: An in vivo study.

    PubMed

    Nikzad, Safoora; Hashemi, Bijan; Hasan, Zuhair Saraf; Mozdarani, Hossein; Baradaran-Ghahfarokhi, Milad; Amini, Payam

    2016-02-01

    Purpose To investigate the effect of increasing the overall treatment time as well as delivering the compensating doses on the Balb/c breast adenocarcinoma (4T1) tumor. Materials and methods A total of 72 mice were divided into two aliquots (classes A and B) based on the initial size of their induced tumor. Each class was divided into a control and several treatment groups. Among the treatment groups, group 1 was continuously exposed to 2 Gy irradiation, and groups 2 and 3 received two subfractions of 1 Gy over the total treatment times of 30 and 60 min, respectively. To investigate the effect of compensating doses, calculated based on the developed linear quadratic model (LQ) model, the remaining two groups (groups 4 and 5) received two subfractions of 1.16 and 1.24 Gy over the total treatment times of 30 and 60 min, respectively. The growing curves, Tumor Growth Time (TGT), Tumor Growth Delay Time (TGDT) and the survival of the animals were studied. Results For class A (tumor size ≤ 30 mm(3)), the average tumor size in the irradiated groups 1-5 was considerably different compared to the control group as one unit (day) change in time, by amount of -160.8, -158.9, +39.4 and +44.0, respectively. While these amounts were +22.0, +17.9, -21.7 and -0.1 for class B (tumor size ≥ 400 mm(3)). For the class A of animals, the TGT and TGDT parameters were significantly lower (0 ≤ 0.05) for the groups 2 and 3, compared to group 1. There was no significant difference (p > 0.05) between groups 1, 4 and 5 in this class. There was no significant difference (p > 0.05) between all the treated groups in class B. Conclusions Increasing total treatment time affects the radiobiological efficiency of treatment especially in small-sized tumor. The compensating doses derived from the LQ model can be used to compensate the effects of prolonged treatment times at in vivo condition. PMID:26630280

  20. Ex vivo optical metabolic measurements from cultured tissue reflect in vivo tissue status

    NASA Astrophysics Data System (ADS)

    Walsh, Alex J.; Poole, Kristin M.; Duvall, Craig L.; Skala, Melissa C.

    2012-11-01

    Optical measurements of metabolism are ideally acquired in vivo; however, intravital measurements are often impractical. Accurate ex vivo assessments would greatly broaden the applicability of optical measurements of metabolism. We investigate the use of live tissue culture experiments to serve as a surrogate for in vivo metabolic measurements. To validate this approach, NADH and FAD fluorescence intensity and lifetime images were acquired with a two-photon microscope from hamster cheek pouch epithelia in vivo, from biopsies maintained in live tissue culture up to 48 h, and from flash-frozen and thawed biopsies. We found that the optical redox ratio (fluorescence intensity of NADH/FAD) of the cultured biopsy was statistically identical to the in vivo measurement until 24 h, while the redox ratio of the frozen-thawed samples decreased by 15% (p<0.01). The NADH mean fluorescence lifetime (?m) remained unchanged (p>0.05) during the first 8 h of tissue culture, while the NADH ?m of frozen-thawed samples increased by 13% (p<0.001). Cellular morphology did not significantly change between in vivo, cultured, and frozen-thawed tissues (p>0.05). All results were consistent across multiple depth layers in this stratified squamous epithelial tissue. Histological markers for proliferation and apoptosis also confirm the viability of tissues maintained in culture. This study suggests that short-term ex vivo tissue culture may be more appropriate than frozen-thawed tissue for optical metabolic and morphologic measurements that approximate in vivo status.

  1. An In Vivo Study of Low-Dose Intra-Articular Tranexamic Acid Application with Prolonged Clamping Drain Method in Total Knee Replacement: Clinical Efficacy and Safety.

    PubMed

    Sa-Ngasoongsong, Paphon; Chanplakorn, Pongsthorn; Wongsak, Siwadol; Uthadorn, Krisorn; Panpikoon, Tanapong; Jittorntam, Paisan; Aryurachai, Katcharin; Angchaisukisiri, Pantap; Kawinwonggowit, Viroj

    2015-01-01

    Background. Recently, combined intra-articular tranexamic acid (IA-TXA) injection with clamping drain method showed efficacy for blood loss and transfusion reduction in total knee replacement (TKR). However, until now, none of previous studies revealed the effect of this technique on pharmacokinetics, coagulation, and fibrinolysis. Materials and Methods. An experimental study was conducted, during 2011-2012, in 30 patients undergoing unilateral TKR. Patients received IA-TXA application and then were allocated into six groups regarding clamping drain duration (2-, 4-, 6-, 8-, 10-, and 12-hours). Blood and drainage fluid were collected to measure tranexamic acid (TXA) level and related coagulation and fibrinolytic markers. Postoperative complication was followed for one year. Results. There was no significant difference of serum TXA level at 2 hour and 24 hour among groups (p < 0.05). Serum TXA level at time of clamp release was significantly different among groups with the highest level at 2 hour (p < 0.0001). There was no significant difference of TXA level in drainage fluid, postoperative blood loss, blood transfusion, and postoperative complications (p < 0.05).??Conclusions. Low-dose IA-TXA application in TKR with prolonged clamping drain method is a safe and effective blood conservative technique with only minimal systemic absorption and without significant increase in systemic absorption over time. PMID:26583092

  2. An In Vivo Study of Low-Dose Intra-Articular Tranexamic Acid Application with Prolonged Clamping Drain Method in Total Knee Replacement: Clinical Efficacy and Safety

    PubMed Central

    Sa-ngasoongsong, Paphon; Chanplakorn, Pongsthorn; Wongsak, Siwadol; Uthadorn, Krisorn; Panpikoon, Tanapong; Jittorntam, Paisan; Aryurachai, Katcharin; Angchaisukisiri, Pantap; Kawinwonggowit, Viroj

    2015-01-01

    Background. Recently, combined intra-articular tranexamic acid (IA-TXA) injection with clamping drain method showed efficacy for blood loss and transfusion reduction in total knee replacement (TKR). However, until now, none of previous studies revealed the effect of this technique on pharmacokinetics, coagulation, and fibrinolysis. Materials and Methods. An experimental study was conducted, during 2011-2012, in 30 patients undergoing unilateral TKR. Patients received IA-TXA application and then were allocated into six groups regarding clamping drain duration (2-, 4-, 6-, 8-, 10-, and 12-hours). Blood and drainage fluid were collected to measure tranexamic acid (TXA) level and related coagulation and fibrinolytic markers. Postoperative complication was followed for one year. Results. There was no significant difference of serum TXA level at 2 hour and 24 hour among groups (p < 0.05). Serum TXA level at time of clamp release was significantly different among groups with the highest level at 2 hour (p < 0.0001). There was no significant difference of TXA level in drainage fluid, postoperative blood loss, blood transfusion, and postoperative complications (p < 0.05).  Conclusions. Low-dose IA-TXA application in TKR with prolonged clamping drain method is a safe and effective blood conservative technique with only minimal systemic absorption and without significant increase in systemic absorption over time. PMID:26583092

  3. Photothermal image flow cytometry in vivo

    NASA Astrophysics Data System (ADS)

    Zharov, Vladimir P.; Galanzha, Ekaterina I.; Tuchin, Valery V.

    2005-03-01

    The capability of photothermal (PT) microscopy to image moving, unlabeled cells in real time in vivo is demonstrated in a study of circulating red and white blood cells in blood and lymph microvessels of rat mesentery. Potential applications of this optical tool, called PT flow cytometry, are discussed.

  4. 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

    Tamaki, Tomoaki; Iwakawa, Mayumi Ohno, Tatsuya; Imadome, Kaori; Nakawatari, Miyako; Sakai, Minako; Tsujii, Hirohiko; Nakano, Takashi; Imai, Takashi

    2009-05-01

    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.

  5. In vivo RNAi: Today and Tomorrow

    PubMed Central

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

    2010-01-01

    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

  6. THz Medical Imaging: in vivo Hydration Sensing

    PubMed Central

    Taylor, Zachary D.; Singh, Rahul S.; Bennett, David B.; Tewari, Priyamvada; Kealey, Colin P.; Bajwa, Neha; Culjat, Martin O.; Stojadinovic, Alexander; Lee, Hua; Hubschman, Jean-Pierre; Brown, Elliott R.; Grundfest, Warren S.

    2015-01-01

    The application of THz to medical imaging is experiencing a surge in both interest and federal funding. A brief overview of the field is provided along with promising and emerging applications and ongoing research. THz imaging phenomenology is discussed and tradeoffs are identified. A THz medical imaging system, operating at ~525 GHz center frequency with ~125 GHz of response normalized bandwidth is introduced and details regarding principles of operation are provided. Two promising medical applications of THz imaging are presented: skin burns and cornea. For burns, images of second degree, partial thickness burns were obtained in rat models in vivo over an 8 hour period. These images clearly show the formation and progression of edema in and around the burn wound area. For cornea, experimental data measuring the hydration of ex vivo porcine cornea under drying is presented demonstrating utility in ophthalmologic applications. PMID:26085958

  7. Radical protection in the visible and infrared by a hyperforin-rich cream--in vivo versus ex vivo methods.

    PubMed

    Arndt, Sophia; Haag, Stefan F; Kleemann, Anke; Lademann, Juergen; Meinke, Martina C

    2013-05-01

    The formation of radicals plays an important role in the development of atopic eczema or barrier-disrupted skin. We evaluated the radical scavenging effect of a cream containing a Hypericum perforatum extract rich in hyperforin in a double-blind placebo-controlled study on 11 healthy volunteers. Electron paramagnetic resonance spectroscopy was applied to determine radical formation during VIS/NIR irradiation of the inner forearm. The results were compared to ex vivo investigations on excised porcine ear skin after a single application of the creams. The non-treated skin was measured as control. The absolute values and the kinetics are not comparable for ex vivo and in vivo radical formation. Whereas in vivo, the radical production decreases with time, it remains stable ex vivo over the investigated timescale. Nevertheless, ex vivo methods could be developed to estimate the protection efficiency of creams. In vivo as well as ex vivo, the radical formation could be reduced by almost 80% when applying the hyperforin-rich cream onto the skin, whereas placebo resulted in about 60%. In vivo, a daylong protection effect could be validated after a 4-week application time of the cream indicating that a regular application is necessary to obtain the full effect. PMID:23614743

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

    PubMed Central

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

    2015-01-01

    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

  9. Long-Term Cultures of Human Cornea Limbal Explants Form 3D Structures Ex Vivo – Implications for Tissue Engineering and Clinical Applications

    PubMed Central

    Nagymihály, Richárd; Josifovska, Natasha; Andjelic, Sofija; Veréb, Zoltán; Facskó, Andrea; Moe, Morten C.; Petrovski, Goran

    2015-01-01

    Long-term cultures of cornea limbal epithelial stem cells (LESCs) were developed and characterized for future tissue engineering and clinical applications. The limbal tissue explants were cultivated and expanded for more than 3 months in medium containing serum as the only growth supplement and without use of scaffolds. Viable 3D cell outgrowth from the explants was observed within 4 weeks of cultivation. The outgrowing cells were examined by immunofluorescent staining for putative markers of stemness (ABCG2, CK15, CK19 and Vimentin), proliferation (p63α, Ki-67), limbal basal epithelial cells (CK8/18) and differentiated cornea epithelial cells (CK3 and CK12). Morphological and immunostaining analyses revealed that long-term culturing can form stratified 3D tissue layers with a clear extracellular matrix deposition and organization (collagen I, IV and V). The LESCs showed robust expression of p63α, ABCG2, and their surface marker fingerprint (CD117/c-kit, CXCR4, CD146/MCAM, CD166/ALCAM) changed over time compared to short-term LESC cultures. Overall, we provide a model for generating stem cell-rich, long-standing 3D cultures from LESCs which can be used for further research purposes and clinical transplantation. PMID:26580800

  10. Long-Term Cultures of Human Cornea Limbal Explants Form 3D Structures Ex Vivo - Implications for Tissue Engineering and Clinical Applications.

    PubMed

    Szab, Dra Jlia; Noer, Agate; Nagymihly, Richrd; Josifovska, Natasha; Andjelic, Sofija; Verb, Zoltn; Facsk, Andrea; Moe, Morten C; Petrovski, Goran

    2015-01-01

    Long-term cultures of cornea limbal epithelial stem cells (LESCs) were developed and characterized for future tissue engineering and clinical applications. The limbal tissue explants were cultivated and expanded for more than 3 months in medium containing serum as the only growth supplement and without use of scaffolds. Viable 3D cell outgrowth from the explants was observed within 4 weeks of cultivation. The outgrowing cells were examined by immunofluorescent staining for putative markers of stemness (ABCG2, CK15, CK19 and Vimentin), proliferation (p63?, Ki-67), limbal basal epithelial cells (CK8/18) and differentiated cornea epithelial cells (CK3 and CK12). Morphological and immunostaining analyses revealed that long-term culturing can form stratified 3D tissue layers with a clear extracellular matrix deposition and organization (collagen I, IV and V). The LESCs showed robust expression of p63?, ABCG2, and their surface marker fingerprint (CD117/c-kit, CXCR4, CD146/MCAM, CD166/ALCAM) changed over time compared to short-term LESC cultures. Overall, we provide a model for generating stem cell-rich, long-standing 3D cultures from LESCs which can be used for further research purposes and clinical transplantation. PMID:26580800

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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.

  12. Preliminary in vivo breast vibro-acoustography results with a quasi 2-dimensional array transducer: a step forward towards clinical applications

    PubMed Central

    Mehrmohammadi, Mohammad; Fazzio, Robert T.; Whaley, Dana H.; Pruthi, Sandhya; Kinnick, Randall R.; Fatemi, Mostafa; Alizad, Azra

    2014-01-01

    We have previously investigated the application of a novel imaging modality, vibro-acoustography (VA) using an annular confocal transducer (confocal VA), integrated into a clinical prone stereotactic mammography system to detect various breast abnormalities. To shorten the scanning time and provide improved coverage of the breast, we have evolved our imaging system by implementing VA on a clinical ultrasound scanner equipped with a “quasi-2-dimensional” array transducer. We call this technique “quasi-2D vibro-acoustography” (Q2DVA). A clinical ultrasound scanner (GE Vivid 7) was modified to perform both ultrasound (US) imaging and VA using an array transducer consisting of a matrix of 12 rows by 70 columns of ultrasound elements. The newly designed system was used to perform VA on patients with either benign or cancerous lesions. Our results indicate that benign and malignant solid breast lesions were easily detected using our newly modified VA system. It was also possible to detect micro-calcifications within the breast. Our results suggest that with further development, Q2DVA could provide high-resolution diagnostic information in the clinical setting and may be used either as a stand-alone or as a complementary tool in support of other clinical imaging modalities. PMID:25438862

  13. Synthesis, Characterization, and Nanoencapsulation of Tetrathiatriarylmethyl and Tetrachlorotriarylmethyl (Trityl) Radical DerivativesA Study To Advance Their Applicability as in Vivo EPR Oxygen Sensors.

    PubMed

    Frank, Juliane; Elewa, Marwa; Said, Mohamed M; El Shihawy, Hosam A; El-Sadek, Mohamed; Mller, Diana; Meister, Annette; Hause, Gerd; Drescher, Simon; Metz, Hendrik; Imming, Peter; Mder, Karsten

    2015-07-01

    Tissue oxygenation plays an important role in the pathophysiology of various diseases and is often a marker of prognosis and therapeutic response. EPR (ESR) is a suitable noninvasive oximetry technique. However, to reliably deploy soluble EPR probes as oxygen sensors in complex biological systems, there is still a need to investigate and improve their specificity, sensitivity, and stability. We reproducibly synthesized various derivatives of tetrathiatriarylmethyl and tetrachlorotriarylmethyl (trityl) radicals. Hydrophilic radicals were investigated in aqueous solution mimicking physiological conditions by, e.g., variation of viscosity and ionic strength. Their specificity was satisfactory, but the oxygen sensitivity was low. To enhance the capability of trityl radicals as oxygen sensors, encapsulation into oily core nanocapsules was performed. Thus, different lipophilic triesters were prepared and characterized in oily solution employing oils typically used in drug formulations, i.e., middle-chain triglycerides and isopropyl myristate. Our screening identified the deuterated ethyl ester of D-TAM (radical 13) to be suitable. It had an extremely narrow single EPR line under anoxic conditions and excellent oxygen sensitivity. After encapsulation, it retained its oxygen responsiveness and was protected against reduction by ascorbic acid. These biocompatible and highly sensitive nanosensors offer great potential for future EPR oximetry applications in preclinical research. PMID:26020133

  14. Ex Vivo Application of Secreted Metabolites Produced by Soil-Inhabiting Bacillus spp. Efficiently Controls Foliar Diseases Caused by Alternaria spp.

    PubMed

    Ali, Gul Shad; El-Sayed, Ashraf S A; Patel, Jaimin S; Green, Kari B; Ali, Mohammad; Brennan, Mary; Norman, David

    2015-01-01

    Bacterial biological control agents (BCAs) are largely used as live products to control plant pathogens. However, due to variable environmental and ecological factors, live BCAs usually fail to produce desirable results against foliar pathogens. In this study, we investigated the potential of cell-free culture filtrates of 12 different bacterial BCAs isolated from flower beds for controlling foliar diseases caused by Alternaria spp. In vitro studies showed that culture filtrates from two isolates belonging to Bacillus subtilis and Bacillus amyloliquefaciens displayed strong efficacy and potencies against Alternaria spp. The antimicrobial activity of the culture filtrate of these two biological control agents was effective over a wider range of pH (3.0 to 9.0) and was not affected by autoclaving or proteolysis. Comparative liquid chromatography-mass spectrometry (LC-MS) analyses showed that a complex mixture of cyclic lipopeptides, primarily of the fengycin A and fengycin B families, was significantly higher in these two BCAs than inactive Bacillus spp. Interaction studies with mixtures of culture filtrates of these two species revealed additive activity, suggesting that they produce similar products, which was confirmed by LC-tandem MS analyses. In in planta pre- and postinoculation trials, foliar application of culture filtrates of B. subtilis reduced lesion sizes and lesion frequencies caused by Alternaria alternata by 68 to 81%. Taken together, our studies suggest that instead of live bacteria, culture filtrates of B. subtilis and B. amyloliquefaciens can be applied either individually or in combination for controlling foliar diseases caused by Alternaria species. PMID:26519395

  15. Ex vivo lung perfusion.

    PubMed

    Reeb, Jeremie; Cypel, Marcelo

    2016-03-01

    Lung transplantation is an established life-saving therapy for patients with end-stage lung disease. Unfortunately, greater success in lung transplantation is hindered by a shortage of lung donors and the relatively poor early-, mid-, and long-term outcomes associated with severe primary graft dysfunction. Ex vivo lung perfusion has emerged as a modern preservation technique that allows for a more accurate lung assessment and improvement in lung quality. This review outlines the: (i) rationale behind the method; (ii) techniques and protocols; (iii) Toronto ex vivo lung perfusion method; (iv) devices available; and (v) clinical experience worldwide. We also highlight the potential of ex vivo lung perfusion in leading a new era of lung preservation. PMID:26700566

  16. Ex vivo DNA Assembly.

    PubMed

    Fisher, Adam B; Canfield, Zachary B; Hayward, Laura C; Fong, Stephen S; McArthur, George H

    2013-01-01

    Even with decreasing DNA synthesis costs there remains a need for inexpensive, rapid, and reliable methods for assembling synthetic DNA into larger constructs or combinatorial libraries. Advances in cloning techniques have resulted in powerful in vitro and in vivo assembly of DNA. However, monetary and time costs have limited these approaches. Here, we report an ex vivo DNA assembly method that uses cellular lysates derived from a commonly used laboratory strain of Escherichia coli for joining double-stranded DNA with short end homologies embedded within inexpensive primers. This method concurrently shortens the time and decreases costs associated with current DNA assembly methods. PMID:25024067

  17. In vivo and ex vivo imaging with ultrahigh resolution full-field OCT

    NASA Astrophysics Data System (ADS)

    Grieve, Kate; Moneron, Gael; Schwartz, Wilfrid; Boccara, Albert C.; Dubois, Arnaud

    2005-08-01

    Imaging of in vivo and ex vivo biological samples using full-field optical coherence tomography is demonstrated. Three variations on the original full-field optical coherence tomography instrument are presented, and evaluated in terms of performance. The instruments are based on the Linnik interferometer illuminated by a white light source. Images in the en face orientation are obtained in real-time without scanning by using a two-dimensional parallel detector array. An isotropic resolution capability better than 1 μm is achieved thanks to the use of a broad spectrum source and high numerical aperture microscope objectives. Detection sensitivity up to 90 dB is demonstrated. Image acquisition times as short as 10 μs per en face image are possible. A variety of in vivo and ex vivo imaging applications is explored, particularly in the fields of embryology, ophthalmology and botany.

  18. Noninvasive photoacoustic microscopy of methemoglobin in vivo

    NASA Astrophysics Data System (ADS)

    Tang, Min; Zhou, Yong; Zhang, Ruiying; Wang, Lihong V.

    2015-03-01

    Various causes can lead to methemoglobinemia, and it has the potential to be confused with other diseases. In vivo measurements of methemoglobin have significant applications in the clinics. We quantified the average and the distributed percentage of methemoglobin both in vitro and in vivo using photoacoustic microscopy (PAM). Based on the absorption spectra of methemoglobin, oxyhemoglobin, and deoxyhemoglobin, three wavelengths were chosen to differentiate methemoglobin from the others. We imaged the methemoglobin percentage in microtubes that mimicked blood vessels as a phantom experiment. The methemoglobin concentrations calculated from the photoacoustic signals were in accordance with the preset concentrations. We also demonstrated the ability of PAM to quantitatively image methemoglobin distribution in vivo in a mouse ear.

  19. Improving in vivo calibration phantoms

    SciTech Connect

    Lynch, T.P.; Olsen, P.C.

    1991-10-01

    Anthropomorphic phantoms have been the basis for quantification of radioactive material in the body using in vivo measurements. The types of phantoms used and the degree of anthropomorphic detail vary depending on the counting application, the radioactive material to be measured, phantom availability and cost. Consequently, measurement results for the same types of radioactive material from different facilities are not always comparable. At a February 1990 meeting at the National Institute of Standards and Technology (NIST) the need to develop the gold standards'' or primary reference standards for in vivo phantoms was discussed in detail. The consensus of the attendees at the meeting was that the state of the art in phantoms was adequate as a starting point and that there was no need to start phantom development from scratch. In particular, the torso phantom developed at the Lawrence Livermore National Laboratory (LLNL) and its commercial progeny, the bottle manikin absorption (BOMAB) phantom and the American National Standards Institute (ANSI) Standard N44.3 thyroid phantom, were identified as the starting points for the development of the primary reference standards. Working groups at the meeting subsequently recommended design improvements for the existing phantom designs. The implementation of these recommendations is the subject of this paper.

  20. Nonimmune Chemotaxis In Vivo

    PubMed Central

    Wiener, Stanley; Lendvai, Sarai; Rogers, Brad; Urivetzky, Morton; Meilman, Edward

    1973-01-01

    Wistar rats were depleted of complement components using purified cobra venom factor (CoF) administered over a 30-hour period by intraperitoneal injection. Complement depletion was confirmed by immunodiffusion assay, hemolytic assay and inhibition of the reverse Arthus reaction. Rats depleted to below 3% of their normal serum complement level showed marked inhibition of chemotaxis into inflammatory fluid produced in polyvinyl sponges 24 hours after implantation into the dorsal subcutaneous region. Subsequent studies were done to test the effect of high local concentrations of CoF on the microcirculation, the neutrophil and the connective tissue. Local exposure of these tissues and cells to CoF in vivo had no inhibiting effect on chemotaxis. Cobra venom factor did not affect neutrophil survival in vitro or in vivo. The most likely hypothesis is that CoF works by depleting complement and that in vivo chemotaxis of the nonbacterial, nonimmune type is complement dependent to the extent of 60 to 80%. The system described allows for quantitative determination of chemotaxis in vivo. PMID:4767264

  1. In vivo radioadaptive response

    PubMed Central

    Wang, B; Vares, G

    2015-01-01

    Radioadaptive response (RAR) describes phenomena where small conditioning doses of ionizing radiation (IR) reduce detrimental effects of subsequent higher IR doses. Current radiation protection regulations do not include RAR because of the large variability in expression among individuals and uncertainties of the mechanism. However, RAR should be regarded as an indispensable factor for estimation and control of individual IR sensitivity. In this article, RAR studies relevant to individual cancer risk are reviewed. Using various stains of mice, carcinogenic RAR has been demonstrated. Consistently much in vivo evidence for RAR with end points of DNA and chromosome damage is reported. Most in vivo RAR studies revealed efficient induction of RAR by chronic or repeated low-dose priming irradiation. Chronic IR-induced RAR was observed also in human individuals after environmental, occupational, and nuclear accident radiation exposure. These observations may be associated with an intrinsically distinct feature of in vivo experimental systems that mainly consist of nonproliferating mature cells. Alternatively, induction of RAR by gap junction-mediated bystander effects suggests that multicellular systems comprising densely communicating cells may be capable of responding to long-lasting low-dose-rate priming irradiation. Regulation by endocrine factors is also a plausible mechanism for RAR at an individual level. Emerging evidence suggests that glucocorticoids, known as stress hormones, participate in in vivo RAR induction following long-term low-dose-rate exposure to IR. PMID:24925363

  2. In-vivo optical investigation of psoriasis

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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 μm2 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 μm. 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 100μm, 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.

  3. 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

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

    2013-09-01

    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

  4. Preliminary results of development of a single-mode Q-switched Nd: YAG ring laser at 213 nm and its application for the microsurgical dissection of retinal tissue ex vivo.

    PubMed

    Yasukawa, Tsutomu; Yafai, Yousef; Wang, Yu-sheng; Dietz, Hartmut; Molotkov, Dimitry; Kongratyuk, Nikolai; Hillrichs, Georg; Wiedemann, Peter; Schastak, Stanislaw I

    2005-01-01

    The Nd: YAG laser family offers wide possibilities for surgery applications in medicine. The radiation at 213 nm provides similar tissue effects as compared to 193 nm excimer lasers, but offers considerable practical advantages in the operating room. As such, it is of considerable interest to create single-mode Q-switched fifth harmonic Nd: YAG pulsed lasers with a high coefficient of efficiency and low divergence. Parameters of the ring three-mirror anisotropic cavity TEM00-Nd: YAG laser were calculated on the basis of the analysis of Gaussian beam behavior in the three-mirror ring cavity, with one convex spherical mirror and one intracavity positive lens. On the hand of numerical calculations a prototype of a single-mode Q-switched Nd: YAG-213 nm laser with an output energy of 4 mJ and a beam divergence of 1 mrad has been developed. At a pulse repetition rate of 50 Hz, it has a generation efficiency in the Q-switched mode of 0,6%. A hollow core wave guide is used in combination with a short length of a special fused silica optical fiber to guide the laser beam. Full-depth dissection of rabbit retina ex vivo was achieved at the intensities of 0.18-0.05 J/cm2 and a repetition rate of 50 Hz, with a linear cutting rate of 6 mm/s. Although the retina was completely cut, heat necrosis of the choroid did not occur. We are currently in the process of testing the dissection of retinal tissue during retinotomy, and the formation of holes in the trabecular meshwork in glaucoma surgery. PMID:15714260

  5. Light dosimetry in vivo.

    PubMed

    Star, W M

    1997-05-01

    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 P3-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 mu a and mu s(1 - g), where mu s 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 mu s (1 - g) 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. PMID:9172258

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  7. Dendritic function in vivo.

    PubMed

    Grienberger, Christine; Chen, Xiaowei; Konnerth, Arthur

    2015-01-01

    Dendrites are the predominant entry site for excitatory synaptic potentials in most types of central neurons. There is increasing evidence that dendrites are not just passive transmitting devices but play active roles in synaptic integration through linear and non-linear mechanisms. Frequently, excitatory synapses are formed on dendritic spines. In addition to relaying incoming electrical signals, spines can play important roles in modifying these signals through complex biochemical processes and, thereby, determine learning and memory formation. Here, we review recent advances in our understanding of the function of spines and dendrites in central mammalian neurons in vivo by focusing particularly on insights obtained from Ca(2+) imaging studies. PMID:25432423

  8. In vivo Noninvasive Small Animal Molecular Imaging

    PubMed Central

    Youn, Hyewon; Hong, Kee-Jong

    2012-01-01

    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

  9. 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)

    Petrossians, Artin

    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.

  10. Applications

    NASA Astrophysics Data System (ADS)

    Stern, Arthur M.

    1986-07-01

    Economic incentives have spurred numerous applications of genetically engineered organisms in manufacture of pharmaceuticals and industrial chemicals. These successes, involving a variety of methods of genetic manipulation, have dispelled early fears that genetic engineering could not be handled safely, even in the laboratory. Consequently, the potential for applications in the wider environment without physical containment is being considered for agriculture, mining, pollution control, and pest control. These proposed applications range from modest extensions of current plant breeding techniques for new disease-resistant species to radical combinations of organisms (for example, nitrogen-fixing corn plants). These applications raise concerns about potential ecological impacts (see chapter 5), largely because of adverse experiences with both deliberate and inadvertent introductions of nonindigenous species.

  11. In vivo dosimetry for IMRT

    SciTech Connect

    Vial, Philip

    2011-05-05

    In vivo dosimetry has a well established role in the quality assurance of 2D radiotherapy and 3D conformal radiotherapy. The role of in vivo dosimetry for IMRT is not as well established. IMRT introduces a range of technical issues that complicate in vivo dosimetry. The first decade or so of IMRT implementation has largely relied upon pre-treatment phantom based dose verification. During that time, several new devices and techniques for in vivo dosimetry have emerged with the promise of providing the ultimate form of IMRT dose verification. Solid state dosimeters continue to dominate the field of in vivo dosimetry in the IMRT era. In this report we review the literature on in vivo dosimetry for IMRT, with an emphasis on clinical evidence for different detector types. We describe the pros and cons of different detectors and techniques in the IMRT setting and the roles that they are likely to play in the future.

  12. Ex vivo expansion of hematopoietic stem cells.

    PubMed

    Xie, JingJing; Zhang, ChengCheng

    2015-09-01

    Ex vivo expansion of hematopoietic stem cells (HSCs) would benefit clinical applications in several aspects, to improve patient survival, utilize cord blood stem cells for adult applications, and selectively propagate stem cell populations after genetic manipulation. In this review we summarize and discuss recent advances in the culture systems of mouse and human HSCs, which include stroma/HSC co-culture, continuous perfusion and fed-batch cultures, and those supplemented with extrinsic ligands, membrane transportable transcription factors, complement components, protein modification enzymes, metabolites, or small molecule chemicals. Some of the expansion systems have been tested in clinical trials. The optimal condition for ex vivo expansion of the primitive and functional human HSCs is still under development. An improved understanding of the mechanisms for HSC cell fate determination and the HSC culture characteristics will guide development of new strategies to overcome difficulties. In the future, development of a combination treatment regimen with agents that enhance self-renewal, block differentiation, and improve homing will be critical. Methods to enhance yields and lower cost during collection and processing should be employed. The employment of an efficient system for ex vivo expansion of HSCs will facilitate the further development of novel strategies for cell and gene therapies including genome editing. PMID:26246379

  13. In vivo and ex vivo evaluation of cosmetic properties of seedcakes.

    PubMed

    Ratz-Łyko, Anna; Arct, Jacek; Pytkowska, Katarzyna; Majewski, Sławomir

    2015-04-01

    The seedcakes are a potential source of natural bioactive substances: antioxidants, protein, and carbohydrates. Thus, they may scavenge free radicals and have an effect on the stratum corneum hydration and epidermal barrier function. The aim of the study was to evaluate the in vivo and ex vivo properties of emulsions with the seedcake extracts using the pH meter, corneometer, tewameter, methyl nicotinate model of micro-inflammation in human skin, and tape stripping of the stratum corneum. The in vivo and ex vivo studies showed that the emulsions with Oenothera biennis, Borago officinalis, and Nigella sativa seedcake extracts have anti-inflammatory and antioxidant activity. The 6-week topical application of the emulsions with the B. officinalis and N. sativa seedcakes significantly reduced skin irritation and influenced the improvement of the skin hydration and epidermal barrier function compared with placebo. The seedcakes due to their antioxidant and anti-inflammatory activities have potential application in anti-aging, moisturizing, mitigating, and protective cosmetics. PMID:25415370

  14. In vivo and ex vivo analysis of tubule function.

    PubMed

    Stockand, James D; Vallon, Volker; Ortiz, Pablo

    2012-10-01

    Analysis of tubule function with in vivo and ex vivo approaches has been instrumental in revealing renal physiology. This work allows assignment of functional significance to known gene products expressed along the nephron, primary of which are proteins involved in electrolyte transport and regulation of these transporters. Not only we have learned much about the key roles played by these transport proteins and their proper regulation in normal physiology but also the combination of contemporary molecular biology and molecular genetics with in vivo and ex vivo analysis opened a new era of discovery informative about the root causes of many renal diseases. The power of in vivo and ex vivo analysis of tubule function is that it preserves the native setting and control of the tubule and proteins within tubule cells enabling them to be investigated in a "real-life" environment with a high degree of precision. In vivo and ex vivo analysis of tubule function continues to provide a powerful experimental outlet for testing, evaluating, and understanding physiology in the context of the novel information provided by sequencing of the human genome and contemporary genetic screening. These tools will continue to be a mainstay in renal laboratories as this discovery process continues and as we continue to identify new gene products functionally compromised in renal disease. PMID:23720256

  15. Manipulating megakaryocytes to manufacture platelets ex vivo

    PubMed Central

    Karagiannis, P; Eto, K

    2015-01-01

    Historically, platelet transfusion has proven a reliable way to treat patients suffering from thrombocytopenia or similar ailments. An undersupply of donors, however, has demanded alternative platelet sources. Scientists have therefore sought to recapitulate the biological events that convert hematopoietic stem cells into platelets in the laboratory. Such platelets have shown good function and potential for treatment. Yet the number manufactured ex vivo falls well short of clinical application. Part of the reason is the remarkable gaps in our understanding of the molecular mechanisms driving platelet formation. Using several stem cell sources, scientists have progressively clarified the chemical signaling and physical microenvironment that optimize ex vivo platelets and reconstituted them in synthetic environments. Key advances in cell reprogramming and the ability to propagate self-renewal have extended the lifetime of megakaryocytes to increase the pool of platelet progenitors. PMID:26149050

  16. Profiling constitutive proteolytic events in vivo

    PubMed Central

    Timmer, JohnC.; Enoksson, Mari; Wildfang, Eric; Zhu, Wenhong; Igarashi, Yoshinobu; Denault, Jean-Benard; Ma, Yuliang; Dummitt, Benjamin; Chang, Yie-Hwa; Mast, AlanE.; Eroshkin, Alexey; Smith, JeffreyW.; Tao, W.Andy; Salvesen, GuyS.

    2007-01-01

    Most known organisms encode proteases that are crucial for constitutive proteolytic events. In the present paper, we describe a method to define these events in proteomes from Escherichia coli to humans. The method takes advantage of specific N-terminal biotinylation of protein samples, followed by affinity enrichment and conventional LC (liquid chromatography)MS/MS (tandem mass spectrometry) analysis. The method is simple, uses conventional and easily obtainable reagents, and is applicable to most proteomics facilities. As proof of principle, we demonstrate profiles of proteolytic events that reveal exquisite in vivo specificity of methionine aminopeptidase in E. coli and unexpected processing of mitochondrial transit peptides in yeast, mouse and human samples. Taken together, our results demonstrate how to rapidly distinguish real proteolysis that occurs in vivo from the predictions based on in vitro experiments. PMID:17650073

  17. Advanced tools for in vivo skin analysis.

    PubMed

    Cal, Krzysztof; Zakowiecki, Daniel; Stefanowska, Justyna

    2010-05-01

    A thorough examination of the skin is essential for accurate disease diagnostics, evaluation of the effectiveness of topically applied drugs and the assessment of the results of dermatologic surgeries such as skin grafts. Knowledge of skin parameters is also important in the cosmetics industry, where the effects of skin care products are evaluated. Due to significant progress in the electronics and computer industries, sophisticated analytic devices are increasingly available for day-to-day diagnostics. The aim of this article is to review several advanced methods for in vivo skin analysis in humans: magnetic resonance imaging, electron paramagnetic resonance, laser Doppler flowmetry and time domain reflectometry. The molecular bases of these techniques are presented, and several interesting applications in the field are discussed. Methods for in vivo assessment of the biomechanical properties of human skin are also reviewed. PMID:20534081

  18. Evaluation of dermal extracellular matrix and epidermal-dermal junction modifications using matrix-assisted laser desorption/ionization mass spectrometric imaging, in vivo reflectance confocal microscopy, echography, and histology: effect of age and peptide applications.

    PubMed

    Mondon, Philippe; Hillion, Mlanie; Peschard, Olivier; Andre, Nada; Marchand, Thibault; Doridot, Emmanuel; Feuilloley, Marc Gj; Pionneau, Cdric; Chardonnet, Solenne

    2015-06-01

    This study was conducted to establish a new methodology for evaluating elements of dermal extracellular matrix (ECM), of epidermal-dermal junction (EDJ), and effects of molecules which can modulate their synthesis. This methodology is based on matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI). In vivo reflectance confocal microscopy (in vivo RCM) and echography were also used. Using immunohistochemistry methods on explants, age-related modification data were obtained for selected dermal ECM and EDJ proteins (collagen I, collagen IV, collagen VII, collagen XVII, nidogen I, decorin/decorunt) and used as reference for MALDI-MSI studies. A methodology was developed with MALDI-MSI to map epidermis and dermis proteins. Then MALDI-MSI was used to study age modifications. In vivo RCM and high-frequency ultrasounds were used to evaluate ECM and EDJ undulation modifications caused by aging. Anti-aging molecule evaluations were performed with a blend of palmitoyl oligopeptide and palmitoyl tetrapeptide-7. Immunohistochemistry studies demonstrated that the selected proteins were found to be less abundant in aged group explants vs. young group except for decorin. MALDI-MSI studies correlated the results obtained for decorin. In vivo RCM measurements indicated a decrease of EDJ undulation depth with age and ECM modifications in the upper part of dermis. Echography demonstrated that the peptide blend reduced subepidermal low-echogenic band thickness and improved its density. In vivo RCM studies indicated that the peptides improved the ECM structure vs. placebo. This preliminary MALDI-MSI study raised some technical difficulties that were overcome. Further studies will be conducted to identify more proteins and to demonstrate the interest of this method for cosmetic evaluations. PMID:25817264

  19. Imaging schistosomes in vivo

    PubMed Central

    Krautz-Peterson, Greice; Ndegwa, David; Vasquez, Kristine; Korideck, Houari; Zhang, Jun; Peterson, Jeffrey D.; Skelly, Patrick J.

    2009-01-01

    Schistosomes are intravascular, parasitic helminths that cause a chronic, often debilitating disease afflicting over 200 million people in over 70 countries. Here we describe novel imaging methods that, for the first time, permit visualization of live schistosomes within their living hosts. The technology centers on fluorescent agent uptake and activation in the parasites gut, and subsequent detection and signal quantitation using fluorescence molecular tomography (FMT). There is a strong positive correlation between the signal detected and parasite number. Schistosoma mansoni parasites of both sexes recovered from infected experimental animals exhibit vivid fluorescence throughout their intestines. Likewise, the remaining important human schistosome parasites, S. japonicum and S. hematobium, also exhibit gut fluorescence when recovered from infected animals. Imaging has been used to efficiently document the decline in parasite numbers in infected mice treated with the antischistosome drug praziquantel. This technology will provide a unique opportunity both to help rapidly identify much-needed, novel antischistosome therapies and to gain direct visual insight into the intravascular lives of the major schistosome parasites of humans.Krautz-Peterson, G., Ndegwa, D., Vasquez, K., Korideck, H., Zhang, J., Peterson, J. D., Skelly, P. J. Imaging schistosomes in vivo. PMID:19346298

  20. Nanocrystal targeting in vivo

    NASA Astrophysics Data System (ADS)

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

    2002-10-01

    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.

  1. Cystoscopic optical coherence tomography for urinary bladder imaging in vivo

    NASA Astrophysics Data System (ADS)

    Wang, Z. G.; Adler, H.; Chan, D.; Jain, A.; Xie, H. K.; Wu, Z. L.; Pan, Y. T.

    2006-02-01

    This paper summarizes the development of new 2D MEMS mirrors and the pertinent modification to improve OCT endoscopic catheter packaging suitable for in vivo imaging diagnosis of bladder cancers. Comparative study of the newly developed endocopic OCT versus the bench-top OCT is presented. Results of in vivo OCT cystoscopy based on a porcine acute inflammation model are presented to compare time-domain OCT and spectral-domain OCT for in vivo imaging. In addition, results of spectral-domain Doppler OCT are presented to image blood flow in the lamina propria of the bladder. The results of our in vivo animal study using the presented OCT endoscope are discussed for potential problems in the future clinical applications.

  2. A method to study in vivo stability of DNA nanostructures?

    PubMed Central

    Surana, Sunaina; Bhatia, Dhiraj; Krishnan, Yamuna

    2013-01-01

    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

  3. Endocavitary in vivo Dosimetry for IMRT Treatments of Gynecologic Tumors

    SciTech Connect

    Cilla, Savino; Macchia, Gabriella; Digesu, Cinzia; Deodato, Francesco; Sabatino, Domenico; Morganti, Alessio G.; Piermattei, Angelo

    2011-01-01

    The accuracy and reproducibility of endometrial carcinoma treatment with intensity-modulated radiotherapy (IMRT) was assessed by means of in vivo dosimetry. Six patients who had previously undergone radical hysterectomy for endometrial carcinoma were treated with IMRT using a vaginal applicator with radio-opaque fiducial markers. An ion-chamber inserted into the applicator supplied an endocavitary in vivo dosimetry for quality assurance purposes. The ratio R = D/D{sub TPS} between the in vivo measured dose D and the predicted dose by the treatment planning system D{sub TPS} was determined for every fraction of the treatment. Results showed that 90% and 100% of the ratios resulted equal to 1 within 5% and 10%, respectively. The mean value of the ratios distribution for the 6 patients was R = 0.995 and the SD = 0.034. The ratio R* between the measured and predicted total doses for each patient was near to 1, within 2%. The dosimetric results suggest that the use of a vaginal applicator in an image-guided approach could make the interfractions target position stable and reproducible, allowing a safe use of the IMRT technique in the treatment of postoperative vaginal vault. In vivo dosimetry may supply useful information about the discrimination of random vs. systematic errors. The workload is minimum and this in vivo dosimetry can be applied also in the clinical routine.

  4. In Vivo Treg Suppression Assays

    PubMed Central

    Workman, Creg J.; Collison, Lauren W.; Bettini, Maria; Pillai, Meenu R.; Rehg, Jerold E.; Vignali, Dario A.A.

    2011-01-01

    To fully examine the functionality of a regulatory T cell (Treg) population, one needs to assess their ability to suppress in a variety of in vivo models. We describe five in vivo models that examine the suppressive capacity of Tregs upon different target cell types. The advantages and disadvantages of each model includ ing resources, time, and technical expertise required to execute each model are also described. PMID:21287333

  5. In vivo bioresponses to silk proteins.

    PubMed

    Thurber, Amy E; Omenetto, Fiorenzo G; Kaplan, David L

    2015-12-01

    Silks are appealing materials for numerous biomedical applications involving drug delivery, tissue engineering, or implantable devices, because of their tunable mechanical properties and wide range of physical structures. In addition to the functionalities needed for specific clinical applications, a key factor necessary for clinical success for any implanted material is appropriate interactions with the body invivo. This review summarizes our current understanding of the invivo biological responses to silks, including degradation, the immune and inflammatory response, and tissue remodeling with particular attention to vascularization. While we focus in this review on silkworm silk fibroin protein due to the large quantity of invivo data thanks to its widespread use in medical materials and consumer products, spider silk information is also included if available. Silk proteins are degraded in the body on a time course that is dependent on the method of silk fabrication and can range from hours to years. Silk protein typically induces a mild inflammatory response that decreases within a few weeks of implantation. The response involves recruitment and activation of macrophages and may include activation of a mild foreign body response with the formation of multinuclear giant cells, depending on the material format and location of implantation. The number of immune cells present decreases with time and granulation tissue, if formed, is replaced by endogenous, not fibrous, tissue. Importantly, silk materials have not been demonstrated to induce mineralization, except when used in calcified tissues. Due to its ability to be degraded, silk can be remodeled in the body allowing for vascularization and tissue ingrowth with eventual complete replacement by native tissue. The degree of remodeling, tissue ingrowth, or other specific cell behaviors can be modulated with addition of growth or other signaling factors. Silk can also be combined with numerous other materials including proteins, synthetic polymers, and ceramics to enhance its characteristics for a particular function. Overall, the diverse array of silk materials shows excellent bioresponses invivo with low immunogenicity and the ability to be remodeled and replaced by native tissue making it suitable for numerous clinical applications. PMID:26322725

  6. In vivo hepatic gene therapy.

    PubMed

    Ni, Y H

    2001-01-01

    Gene therapy is intended to treat diseases at the gene level by replacing a missense gene with a normal gene or repairing a mutated gene and letting right gene function normally. Hepatic gene therapy applies this idea to the areas of inherited and metabolic liver disease, liver cancer, viral hepatitis, or even the systemic diseases, like hemophilia A and B. The strategies of hepatic gene therapy can be divided into two categories: ex vivo and in vivo. The ex vivo method has to harvest the hepatocytes from the hosts and introduce the gene of interest into the hepatocytes and retransplant the cells back to the liver. The in vivo method constitutes either a local delivery method or a systemic administration. The vectors for in vivo gene transfer include viral or non-viral methods. For the viral methods, retrovirus, lentivirus, adenovirus, adeno-associated virus, or baculovirus had been tried. For the non-viral methods, liposome, liver-specific ligand, or even naked nucleotide had been attempted to achieve the goal of liver-directed gene transfer. Up to now, neither viral nor non-viral vector is perfect. A further modification of the current vectors may improve a new generation of liver-directed gene transfer. PMID:11550406

  7. Spectral characteristics of two-photon autofluorescence and second harmonic generation from human skin in vivo

    NASA Astrophysics Data System (ADS)

    Breunig, Hans G.; König, Karsten

    2011-03-01

    We performed multiphoton imaging of human skin and recorded in combination the complete spectral content of the signals in vivo. The spectra represent the integration of multiphoton signals over the investigated regions of the epidermis and dermis. They are used to study depth-resolved in vivo emission characteristics of main endogenous skin fluorophores like keratin, NAD(P)H, collagen and elastin. The identification of the specific fluorophores is supported by analysis of additional in vivo fluorescence lifetime imaging. Furthermore, as a potential application of spectrally selective imaging the possibility to investigate the penetration of nanoparticles from sunscreen lotion into skin in vivo is discussed.

  8. 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

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

    2003-01-01

    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

  9. Human skin levels of retinoic acid and cytochrome P-450-derived 4-hydroxyretinoic acid after topical application of retinoic acid in vivo compared to concentrations required to stimulate retinoic acid receptor-mediated transcription in vitro.

    PubMed Central

    Duell, E A; Astrm, A; Griffiths, C E; Chambon, P; Voorhees, J J

    1992-01-01

    Metabolism of retinoic acid to a less active metabolite, 4-hydroxyretinoic acid, occurs via cytochrome P-450 isozyme(s). Effect of a pharmacological dose of retinoic acid on the level of retinoic acid in skin and on cytochrome P-450 activity was investigated. A cream containing 0.1% retinoic acid or cream alone was applied topically to adult human skin for four days under occlusion. Treated areas were removed by a keratome and a microsomal fraction was isolated from each biopsy. In vitro incubation of 3H-retinoic acid with microsomes from in vivo retinoic acid treated sites resulted in a 4.5-fold increase (P = 0.0001, n = 13) in its transformation to 4-hydroxyretinoic acid in comparison to in vitro incubations with microsomes from in vivo cream alone treated sites. This cytochrome P-450 mediated activity was oxygen- and NADPH-dependent and was inhibited 68% by 5 microM ketoconazole (P = 0.0035, n = 8) and 51% by carbon monoxide (P = 0.02, n = 6). Cotransfection of individual retinoic acid receptors (RARs) or retinoid X receptor-alpha (RXR-alpha) and a chloramphenicol acetyl transferase (CAT) reporter plasmid containing a retinoic acid responsive element into CV-1 cells was used to determine the ED50 values for stimulation of CAT activity by retinoic acid and its metabolites. Levels of all trans and 13-cis RA in RA-treated tissues were greater than the ED50 values determined for all three RARs with these compounds. Furthermore, the level of all trans RA was greater than the ED50 for RXR-alpha whereas the 4-OH RA level was greater than the ED50 for RAR-beta and RAR-gamma but less than for RAR-alpha and RXR-alpha. These data suggest that there are sufficient amounts of retinoic acid in treated skin to activate gene transcription over both RARs and RXR-alpha. PMID:1328295

  10. Design, synthesis and binding properties of a fluorescent α₉β₁/α₄β₁ integrin antagonist and its application as an in vivo probe for bone marrow haemopoietic stem cells.

    PubMed

    Cao, Benjamin; Hutt, Oliver E; Zhang, Zhen; Li, Songhui; Heazlewood, Shen Y; Williams, Brenda; Smith, Jessica A; Haylock, David N; Savage, G Paul; Nilsson, Susan K

    2014-02-14

    The α9β1 and α4β1 integrin subtypes are expressed on bone marrow haemopoietic stem cells and have important roles in stem cell regulation and trafficking. Although the roles of α4β1 integrin have been thoroughly investigated with respect to HSC function, the role of α9β1 integrin remains poorly characterised. Small molecule fluorescent probes are useful tools for monitoring biological processes in vivo, to determine cell-associated protein localisation and activation, and to elucidate the mechanism of small molecule mediated protein interactions. Herein, we report the design, synthesis and integrin-dependent cell binding properties of a new fluorescent α9β1 integrin antagonist (R-BC154), which was based on a series of N-phenylsulfonyl proline dipeptides and assembled using the Cu(I)-catalyzed azide alkyne cycloaddition (CuAAC) reaction. Using transfected human glioblastoma LN18 cells, we show that R-BC154 exhibits high nanomolar binding affinities to α9β1 integrin with potent cross-reactivity against α4β1 integrin under physiological mimicking conditions. On-rate and off-rate measurements revealed distinct differences in the binding kinetics between α9β1 and α4β1 integrins, which showed faster binding to α4β1 integrin relative to α9β1, but more prolonged binding to the latter. Finally, we show that R-BC154 was capable of binding rare populations of bone marrow haemopoietic stem and progenitor cells when administered to mice. Thus, R-BC154 represents a useful multi-purpose fluorescent integrin probe that can be used for (1) screening small molecule inhibitors of α9β1 and α4β1 integrins; (2) investigating the biochemical properties of α9β1 and α4β1 integrin binding and (3) investigating integrin expression and activation on defined cell phenotypes in vivo. PMID:24363056

  11. Tailoring vessel morphology in vivo

    NASA Astrophysics Data System (ADS)

    Gould, Daniel Joseph

    Tissue engineering is a rapidly growing field which seeks to provide alternatives to organ transplantation in order to address the increasing need for transplantable tissues. One huge hurdle in this effort is the provision of thick tissues; this hurdle exists because currently there is no way to provide prevascularized or rapidly vascularizable scaffolds. To design thick, vascularized tissues, scaffolds are needed that can induce vessels which are similar to the microvasculature found in normal tissues. Angiogenic biomaterials are being developed to provide useful scaffolds to address this problem. In this thesis angiogenic and cell signaling and adhesion factors were incorporated into a biomimetic poly(ethylene glycol) (PEG) hydrogel system. The composition of these hydrogels was precisely tuned to induce the formation of differing vessel morphology. To sensitively measure induced microvascular morphology and to compare it to native microvessels in several tissues, this thesis developed an image-based tool for quantification of scale invariant and classical measures of vessel morphology. The tool displayed great utility in the comparison of native vessels and remodeling vessels in normal tissues. To utilize this tool to tune the vessel response in vivo, Flk1::myr-mCherry fluorescently labeled mice were implanted with Platelet Derived Growth Factor-BB (PDGF-BB) and basic Fibroblast Growth Factor (FGF-2) containing PEG-based hydrogels in a modified mouse corneal angiogenesis assay. Resulting vessels were imaged with confocal microscopy, analyzed with the image based tool created in this thesis to compare morphological differences between treatment groups, and used to create a linear relationship between space filling parameters and dose of growth factor release. Morphological parameters of native mouse tissue vessels were then compared to the linear fit to calculate the dose of growth factors needed to induce vessels similar in morphology to native vessels. Resulting induced vessels did match in morphology to the target vessels. Several other covalently bound signals were then analyzed in the assay and resulting morphology of vessels was compared in several studies which further highlighted the utility of the micropocket assay in conjunction with the image based tool for vessel morphological quantification. Finally, an alternative method to provide rapid vasculature to the constructs, which relied on pre-seeded hydrogels encapsulated endothelial cells was also developed and shown to allow anastamosis between induced host vessels and the implanted construct within 48 hours. These results indicate great promise in the rational design of synthetic, bioactive hydrogels, which can be used as a platform to study microvascular induction for regenerative medicine and angiogenesis research. Future applications of this research may help to develop therapeutic strategies to ameliorate human disease by replacing organs or correcting vessel morphology in the case of ischemic diseases and cancer.

  12. In vivo glucose measurement by surface-enhanced Raman spectroscopy.

    PubMed

    Stuart, Douglas A; Yuen, Jonathan M; Shah, Nilam; Lyandres, Olga; Yonzon, Chanda R; Glucksberg, Matthew R; Walsh, Joseph T; Van Duyne, Richard P

    2006-10-15

    This paper presents the first in vivo application of surface-enhanced Raman scattering (SERS). SERS was used to obtain quantitative in vivo glucose measurements from an animal model. Silver film over nanosphere surfaces were functionalized with a two-component self-assembled monolayer, and subcutaneously implanted in a Sprague-Dawley rat such that the glucose concentration of the interstitial fluid could be measured by spectroscopically addressing the sensor through an optical window. The sensor had relatively low error (RMSEC = 7.46 mg/dL (0.41 mM) and RMSEP = 53.42 mg/dL (2.97 mM). PMID:17037923

  13. Modeling Disease In Vivo With CRISPR/Cas9.

    PubMed

    Dow, Lukas E

    2015-10-01

    The recent advent of CRISPR/Cas9-mediated genome editing has created a wave of excitement across the scientific research community, carrying the promise of simple and effective genomic manipulation of nearly any cell type. CRISPR has quickly become the preferred tool for genetic manipulation, and shows incredible promise as a platform for studying gene function in vivo. I discuss the current application of CRISPR technology to create new in vivo disease models, with a particular focus on how these tools, derived from an adaptive bacterial immune system, are helping us to better model the complexity of human cancer. PMID:26432018

  14. Experimental Cryosurgery Investigations In Vivo

    PubMed Central

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

    2009-01-01

    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

  15. In vivo Raman spectroscopy of cervix cancers

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  16. In vivo dosimetry with thermoluminescent dosimeters in external photon beam radiotherapy.

    PubMed

    Costa, Alessandro M; Barbi, Gustavo L; Bertucci, Edenyse C; Ferreira, Heberton; Sansavino, Simone Z; Colenci, Beatriz; Caldas, Linda V E

    2010-01-01

    The ultimate check of the actual dose delivered to a patient in radiotherapy can only be achieved by using in vivo dosimetry. This work reports a pilot study to test the applicability of a thermoluminescent dosimetric system for performing in vivo entrance dose measurements in external photon beam radiotherapy. The measurements demonstrated the value of thermoluminescent dosimetry as a treatment verification method and its applicability as a part of a quality assurance program in radiotherapy. PMID:19819151

  17. Progress Toward In Vivo Use of siRNAs-II

    PubMed Central

    Rettig, Garrett R; Behlke, Mark A

    2012-01-01

    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

  18. Tracking immune cells in vivo using magnetic resonance imaging

    PubMed Central

    Ahrens, Eric T.; Bulte, Jeff W. M.

    2013-01-01

    The increasing complexity of in vivo imaging technologies, coupled with the development of cell therapies, has fuelled a revolution in immune cell tracking in vivo. Powerful magnetic resonance imaging (MRI) methods are now being developed that use iron oxide- and 19F-based probes. These MRI technologies can be used for image-guided immune cell delivery and for the visualization of immune cell homing and engraftment, inflammation, cell physiology and gene expression. MRI-based cell tracking is now also being applied to evaluate therapeutics that modulate endogenous immune cell recruitment and to monitor emerging cellular immunotherapies. These recent uses show that MRI has the potential to be developed in many applications to follow the fate of immune cells in vivo. PMID:24013185

  19. In Vivo Bioluminescence Imaging of Intratumoral Bacteria.

    PubMed

    Cronin, Michelle; Akin, Ali R; Francis, Kevin P; Tangney, Mark

    2016-01-01

    This chapter describes the use of whole-body bioluminescent imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of bacteria in therapy of cancer. Bacteria present an attractive class of vector for cancer therapy, possessing a natural ability to grow preferentially within tumors following systemic administration. Bacteria engineered to express the lux gene cassette permit BLI detection of the bacteria and tumor sites concurrently. The location and levels of bacteria within tumors over time can be readily examined, visualized in two or three dimensions. The method is applicable to a wide range of bacterial species and tumor xenograft types. This article describes the protocol for analysis of bioluminescent bacteria within subcutaneous tumor-bearing mice. This powerful, and inexpensive, real-time imaging strategy represents an ideal method for the study of bacteria in vivo in the context of cancer research. This protocol outlines the procedure for studying lux-tagged Escherichia coli and Bifidobacterium breve in mice, demonstrating the spatial and temporal readout from 2D and 3D BLI achievable with whole-body in vivo luminescence imaging. PMID:26846803

  20. In vivo orthodontic retainer survival - a review

    PubMed Central

    LABUNET, ANCA VICTORIA; BADEA, MÎNDRA

    2015-01-01

    Background Relapse following orthodontic treatment is a constant concern of orthodontists. Fixed retention is preferred especially for the lower arch by most orthodontists. Objectives This review focuses on in vivo studies. The main objective is to determine the survival rates of different types of retainer: glass-fiber reinforced composite resin, polyethylene or multistrand stainless steel wire bonded to each tooth from canine to canine in the mandibular arch. A second objective is to assess which of these types is less likely to cause additional problems and the third objective is to evaluate the factors that may influence retainer survival. Results and conclusions There were 8 studies identified that matched the objectives stated. Current in vivo studies on survival rate take little notice of the role of the material used for bonding of the fixed retainer. It is not possible to draw a conclusion on reliability of new types of retainers glass fiber reinforced composite resin or polyethylene compared to multistrand stainless steel wire. The multistrand wire remains the gold standard for fixed retention. Although it is a logical outcome that retainer survival is dependent on the application technique, there seems to be no research outcome proving that operator experience, moisture control are essential, nor does patient age or sex have statistically proven effects on survival rates. Adequate studies that involve such aspects should be performed. PMID:26609260

  1. Confocal photothermal flow cytometry in vivo

    NASA Astrophysics Data System (ADS)

    Zharov, Vladimir P.; Galanzha, Ekaterina I.; Ferguson, Scott; Tuchin, Valery V.

    2005-04-01

    The new experimental design of an integrated flow cytometry (FC) is presented, combining high-resolution transmission digital microscopy (TDM) with photothermal (PT), photoacoustic (PA), and fluorescence techniques. We used phantom in vitro to verify this concept with moving living cells, and micro- and nanoparticles. The transistion in vivo study was realized by using unique rat mesentery model for real-time detection of circulating red and white blood cells. The adaptation of confocal schematics to PT microscopy to provide 3-D measurement is discussed. We demonstrated that simulataneous transmission, PT and fluorescent imaging provide the basis for nanodiagnostics and nanotherpeutics in vivo with gold nanoparticles as PT probes and sensitizers as well as identification cells with specific absorbing endogenous and exogenous structures. First attempt to use in parallel PA methods with detection PA signals from single live cells are presented. Potential applications of integrated FC are discussed, including identification of selected cells with different natural absorptive properties, characterization of bioflow (e.g., velocity profile), and PT nanotherapeutics and nanodiagnostics of metastatic cells with gold nanoparticles.

  2. In aqua vivo EPID dosimetry

    SciTech Connect

    Wendling, Markus; McDermott, Leah N.; Mans, Anton; Olaciregui-Ruiz, Igor; Pecharroman-Gallego, Raul; Sonke, Jan-Jakob; Stroom, Joep; Herk, Marcel J.; Mijnheer, Ben van

    2012-01-15

    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.

  3. In-vivo morphologic and spectroscopic investigation of Psoriasis

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

    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 μm. 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 100μm, 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.

  4. Circumferentially aligned fibers guided functional neoartery regeneration invivo.

    PubMed

    Zhu, Meifeng; Wang, Zhihong; Zhang, Jiamin; Wang, Lina; Yang, Xiaohu; Chen, Jingrui; Fan, Guanwei; Ji, Shenglu; Xing, Cheng; Wang, Kai; Zhao, Qiang; Zhu, Yan; Kong, Deling; Wang, Lianyong

    2015-08-01

    An ideal vascular graft should have the ability to guide the regeneration of neovessels with structure and function similar to those of the native blood vessels. Regeneration of vascular smooth muscle cells (VSMCs) with circumferential orientation within the grafts is crucial for functional vascular reconstruction invivo. To date, designing and fabricating a vascular graft with well-defined geometric cues to facilitate simultaneously VSMCs infiltration and their circumferential alignment remains a great challenge and scarcely reported invivo. Thus, we have designed a bi-layered vascular graft, of which the internal layer is composed of circumferentially aligned microfibers prepared by wet-spinning and an external layer composed of random nanofibers prepared by electrospinning. While the internal circumferentially aligned microfibers provide topographic guidance for invivo regeneration of circumferentially aligned VSMCs, the external random nanofibers can offer enhanced mechanical property and prevent bleeding during and after graft implantation. VSMCs infiltration and alignment within the scaffold was then evaluated invitro and in vivo. Our results demonstrated that the circumferentially oriented VSMCs and longitudinally aligned ECs were successfully regenerated invivo after the bi-layered vascular grafts were implanted in rat abdominal aorta. No formation of thrombosis or intimal hyperplasia was observed up to 3 month post implantation. Further, the regenerated neoartery exhibited contraction and relaxation property in response to vasoactive agents. This new strategy may bring cell-free small diameter vascular grafts closer to clinical application. PMID:26001073

  5. In Vivo Programmed Gene Expression Based on Artificial Quorum Networks

    PubMed Central

    Chu, Teng; Huang, Yajun; Hou, Mingyu; Wang, Qiyao; Xiao, Jingfan; Zhang, Yuanxing

    2015-01-01

    The quorum sensing (QS) system, as a well-functioning population-dependent gene switch, has been widely applied in many gene circuits in synthetic biology. In our work, an efficient cell density-controlled expression system (QS) was established via engineering of the Vibrio fischeri luxI-luxR quorum sensing system. In order to achieve in vivo programmed gene expression, a synthetic binary regulation circuit (araQS) was constructed by assembling multiple genetic components, including the quorum quenching protein AiiA and the arabinose promoter ParaBAD, into the QS system. In vitro expression assays verified that the araQS system was initiated only in the absence of arabinose in the medium at a high cell density. In vivo expression assays confirmed that the araQS system presented an in vivo-triggered and cell density-dependent expression pattern. Furthermore, the araQS system was demonstrated to function well in different bacteria, indicating a wide range of bacterial hosts for use. To explore its potential applications in vivo, the araQS system was used to control the production of a heterologous protective antigen in an attenuated Edwardsiella tarda strain, which successfully evoked efficient immune protection in a fish model. This work suggested that the araQS system could program bacterial expression in vivo and might have potential uses, including, but not limited to, bacterial vector vaccines. PMID:25979894

  6. Comparative real-time study of cellular uptake of a formulated conjugated linolenic acid rich nano and conventional macro emulsions and their bioactivity in ex vivo models for parenteral applications.

    PubMed

    Paul, Debjyoti; Mukherjee, Sayani; Chakraborty, Rajarshi; Mallick, Sanjaya K; Dhar, Pubali

    2015-02-01

    The objective of the present study was to fabricate and monitor real-time, impact of a stable conjugated linolenic acid, ?-eleostearic acid (ESA) rich nanoemulsion (NE) formulation (d < 200 nm) vis--vis ESA conventional emulsion (CE) system in ex vivo systems against both endogenous and exogenous reactive oxygen species (ROS). Accordingly, stable nanoemulsion formulation of ESA was engineered with the aid of bitter melon seed oil and non-toxic excipients. Morphology and particle size of the emulsion formulations were studied to validate stability. The real-time rapid uptake of the ESA NE and its increased prophylactic efficacy against induced endogenous and exogenous ROS in terms of cell viability and membrane integrity was evaluated flow-cytometrically and with fluorescence microscopic analysis of different primary cells. It was found that the fabricated non-toxic ESA NE had stable parameters (hydrodynamic mean diameter, particle size distribution and zeta potential) for over 12 weeks. Further, ESA NE at a concentration of ? 70 ?M exhibited maximum efficacy in protecting cells from oxidative damage against both endogenous and exogenous ROS in lymphocytes and hepatocytes as compared to its corresponding presence in the CE formulation. This study provides a real-time empirical evidence on the influence of nano formulation in enhancing bioavailability and antioxidative properties of ESA. PMID:25579219

  7. Development of a method to quantify clindamycin in vitreous humor of rabbits' eyes by UPLC-MS/MS: application to a comparative pharmacokinetic study and in vivo ocular biocompatibility evaluation.

    PubMed

    Fernandes-Cunha, Gabriella M; Gouvea, Dayana Rubio; Fulgncio, Gustavo de Oliveira; Rezende, Cntia M F; da Silva, Gisele Rodrigues; Bretas, Juliana M; Fialho, Slvia Ligrio; Lopes, Norberto Peporine; Silva-Cunha, Armando

    2015-01-01

    Ocular toxoplasmosis may result in uveitis in the posterior segment of the eye, leading to severe visual complications. Clindamycin-loaded poly(lactide-co-glycolide) (PLGA) implants could be applied to treat the ocular toxoplasmosis. In this study, the pharmacokinetic profiles of the drug administrated by PLGA implants and by intravitreal injections in rabbits' eyes were evaluated. The implant released the drug for 6 weeks while the drug administrated by intravitreal injections remained in the vitreous cavity for 2 weeks. Compared to the injected drug, the implants containing clindamycin had higher values of area under the curve (AUC) (39.2 vs 716.7 ng week mL(-1)) and maximum vitreous concentration (Cmax) (8.7 vs 13.83 ng mL(-1)). The implants prolonged the delivery of clindamycin and increased the contact of the drug with the eyes' tissues. Moreover, the in vivo ocular biocompatibility of the clindamycin-loaded PLGA implants was evaluated regarding to the clinical examination of the eyes and the measurement of the intraocular pressure (IOP) during 6 weeks. The implantable devices caused no ocular inflammatory process and induced the increase of the IOP in the fourth week of the study. The IOP augmentation could be related to the maximum concentration of clindamycin released from the implants. In conclusion, the PLGA implants based on clindamycin may be a therapeutic alternative to treat ocular toxoplasmosis. PMID:25459934

  8. Coronary thrombosis: In vivo, ex vivo and in vitro.

    PubMed

    Gorog, Diana A; Saraf, Smriti; Markides, Vias

    2009-01-01

    Acute stent thrombosis remains one of the most important concerns in clinical cardiology. The mechanism is not fully understood but a prothrombotic state is a key component. We describe a case of acute stent thrombosis, within an hour of rescue angioplasty, despite use of full dose fibrinolytic (reteplase) and antiplatelet therapy (aspirin and clopidogrel). Risk of acute stent thrombosis was predicted an hour earlier, when the patient was clinically well, by a novel near-patient test of thrombotic and thrombolytic status (in vitro). Subsequent stent thrombosis was visualised angiographically (in vivo) and confirmed by extraction of the thrombus (ex vivo). The near-patient test sensitively detected reversal of the prothrombotic state after abciximab treatment. We believe this is the first description of the clinical use of a near-patient test within the cardiac catheterisation laboratory to predict risk of imminent stent thrombosis. PMID:21686525

  9. In vivo nanotoxicity assays in plant models.

    PubMed

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

    2012-01-01

    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

  10. 3D ultrafast ultrasound imaging in vivo