Science.gov

Sample records for mesencephalic free-floating tissue

  1. Immunocytochemistry of formalin-fixed human brain tissues: microwave irradiation of free-floating sections.

    PubMed

    Shiurba, R A; Spooner, E T; Ishiguro, K; Takahashi, M; Yoshida, R; Wheelock, T R; Imahori, K; Cataldo, A M; Nixon, R A

    1998-01-01

    Formalin fixation, the chemical process in which formaldehyde binds to cells and tissues, is widely used to preserve human brain specimens from autolytic decomposition. Ultrastructure of cellular and mitochondrial membranes is markedly altered by vesiculation, but this does not interfere with diagnostic evaluation of neurohistology by light microscopy. Serious difficulties are encountered, however, when immunocytochemical staining is attempted. Antigens that are immunoreactive in unfixed frozen sections and protein extracts appear to be concealed or destroyed in formalin-fixed tissues. In dilute aqueous solution, formaldehyde is in equilibrium with methylene glycol and its polymeric hydrates, the balance by far in favor of methylene glyco. Carbonylic formaldehyde is a reactive electrophilic species well known for crosslinking functional groups in tissue proteins, nucleic acids, and polysaccharides. Some of its methylene crosslinks are readily hydrolyzed. Others are stable and irreversible. During immunostaining reactions, intra- and inter-molecular links between macromolecules limit antibody permeation of tissue sections, alter protein secondary structure, and reduce accessibility of antigenic determinants . Accordingly, immunoreactivity is diminished for many antigens. Tissues are rapidly penetrated by methylene glycol, but formaldehyde binding to cellular constituents is relatively slow, increasing progressively until equilibrium is reached. In addition, prolonged storage in formalin may result in acidification of human brain specimens. Low pH favors dissociation of methylene glycol into formaldehyde, further reducing both classical staining and antigen detectability. Various procedures have been devised to counter the antigen masking effects of formaldehyde. Examples include pretreatment of tissue sections with proteases, formic acid, or ultrasound. Recently, heating of mounted sections in ionic salt solution by microwave energy was found to restore many

  2. Vertical pump with free floating check valve

    DOEpatents

    Lindsay, Malcolm

    1980-01-01

    A vertical pump with a bottom discharge having a free floating check valve isposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions.

  3. Methylcellulose during cryopreservation of ventral mesencephalic tissue fragments fails to improve survival and function of cell suspension grafts.

    PubMed

    Sautter, J; Strecker, S; Kupsch, A; Oertel, W H

    1996-02-01

    Cryopreservation may allow long-term storage of fetal ventral mesencephalon (VM) for transplantation in patients suffering from Parkinson's disease (PD). We investigated whether the polymer methylcellulose protects fetal rat VM during cryopreservation in liquid nitrogen and improves survival and function of this tissue as intrastriatal suspension grafts in the 6-hydroxydopamine (6-OHDA) rat model. VM tissue fragments (E14-E15) were either immediately dissociated and grafted as a cell suspension (FRESH) or cryopreserved under controlled conditions for 7 days in a conventional cryoprotective medium (CRYO) or a medium containing 0.1% methylcellulose (mCRYO) and then dissociated and grafted. Rats from the cryo-groups showed only limited behavioral compensation in contrast to complete compensation observed in rats from the FRESH group. Cryopreservation of fetal rat VM decreased the viability of cell suspensions in vitro to about 70%, survival of grafted tyrosine hydroxylase-immunoreactive (TH-IR) neurons to 11% and 20%, and transplant volume to 8% and 17% (mCRYO and CRYO, respectively, compared to FRESH). The addition of 0.1% methylcellulose to tissue fragments during freezing did neither improve in vitro viability nor survival of TH-IR neurons nor behavioral compensation when compared to the control CRYO group. These results suggest that methylcellulose failed to improve survival of cryopreserved dopaminergic ventral mesencephalic neurons.

  4. Cryopreservation, Culture, and Transplantation of Human Fetal Mesencephalic Tissue into Monkeys

    NASA Astrophysics Data System (ADS)

    Redmond, D. E.; Naftolin, F.; Collier, T. J.; Leranth, C.; Robbins, R. J.; Sladek, C. D.; Roth, R. H.; Sladek, J. R.

    1988-11-01

    Studies in animals suggest that fetal neural grafts might restore lost neurological function in Parkinson's disease. In monkeys, such grafts survive for many months and reverse signs of parkinsonism, without attendant graft rejection. The successful and reliable application of a similar transplantation procedure to human patients, however, will require neural tissue obtained from human fetal cadavers, with demonstrated cellular identity, viability, and biological safety. In this report, human fetal neural tissue was successfully grafted into the brains of monkeys. Neural tissue was collected from human fetal cadavers after 9 to 12 weeks of gestation and cryopreserved in liquid nitrogen. Viability after up to 2 months of storage was demonstrated by cell culture and by transplantation into monkeys. Cryopreservation and storage of human fetal neural tissue would allow formation of a tissue bank. The stored cells could then be specifically tested to assure their cellular identity, viability, and bacteriological and virological safety before clinical use. The capacity to collect and maintain viable human fetal neural tissue would also facilitate research efforts to understand the development and function of the human brain and provide opportunities to study neurological diseases.

  5. Free-floating dual-arm robots for space assembly

    NASA Technical Reports Server (NTRS)

    Agrawal, Sunil Kumar; Chen, M. Y.

    1994-01-01

    Freely moving systems in space conserve linear and angular momentum. As moving systems collide, the velocities get altered due to transfer of momentum. The development of strategies for assembly in a free-floating work environment requires a good understanding of primitives such as self motion of the robot, propulsion of the robot due to onboard thrusters, docking of the robot, retrieval of an object from a collection of objects, and release of an object in an object pool. The analytics of such assemblies involve not only kinematics and rigid body dynamics but also collision and impact dynamics of multibody systems. In an effort to understand such assemblies in zero gravity space environment, we are currently developing at Ohio University a free-floating assembly facility with a dual-arm planar robot equipped with thrusters, a free-floating material table, and a free-floating assembly table. The objective is to pick up workpieces from the material table and combine them into prespecified assemblies. This paper presents analytical models of assembly primitives and strategies for overall assembly. A computer simulation of an assembly is developed using the analytical models. The experiment facility will be used to verify the theoretical predictions.

  6. Using K2 To Find Free-floating Planets

    NASA Astrophysics Data System (ADS)

    Henderson, Calen

    2015-12-01

    K2's Campaign 9 (K2C9) will conduct a several square-degree microlensing survey toward the Galactic bulge to detect exoplanets simultaneously from the ground and from space. The ˜0.5 AU baseline between K2 and the Earth during C9 will facilitate satellite parallax measurements for hundreds of microlensing events, some with planetary signatures, allowing for the determination of the mass of and distance to the lens systems. For short timescale events, with durations of ˜1 day, a determination of the parallax will identify that the cause is in fact a very low-mass object, i.e., a free-floating planet. Subsquent high-resolution NIR photometric follow-up can then distinguish between a planet that is widely separated from but gravitationally bound to a host star and one that is truly free-floating.

  7. Using K2 to Find Free-floating Planets

    NASA Astrophysics Data System (ADS)

    Henderson, Calen B.

    2016-01-01

    In 2011, Sumi et al. announced the discovery of an excess of short-timescale microlensing events, which they inferred to be caused by a population of unbound planetary-mass objects. Their result implies that these free-floating planet candidates may constitute an overwhelming fraction of the mass budget for planet formation. K2's Campaign 9 (K2C9) will conduct a ~4 square-degree microlensing survey toward the Galactic bulge and is our first and potentially only opportunity to perform a synoptic survey to measure the masses of a substantial number of short-timescale events. The ˜0.5 AU baseline between K2 and the Earth during C9 will facilitate satellite parallax measurements for short-timescale events, with durations of ˜1 day, which will identify that the cause of the event is in fact a very low-mass object, i.e., a free-floating planet candidate. By taking near-infrared (NIR) photometry during the event and comparing to high-resolution NIR photometry after the event is over, we can then distinguish between a planet that is widely separated from but gravitationally bound to a host star and one that is truly free-floating. Here we overview this procedure, describe the resources available to accomplish it, and detail the expected yields.

  8. Microlensing by Kuiper, Oort, and Free-Floating Planets

    NASA Astrophysics Data System (ADS)

    Gould, Andrew

    2016-08-01

    Microlensing is generally thought to probe planetary systems only out to a few Einstein radii. Microlensing events generated by bound planets beyond about 10 Einstein radii generally do not yield any trace of their hosts, and so would be classified as free floating planets (FFPs). I show that it is already possible, using adaptive optics (AO), to constrain the presence of potential hosts to FFP candidates at separations comparable to the Oort Cloud. With next-generation telescopes, planets at Kuiper-Belt separations can be probed. Next generation telescopes will also permit routine vetting for all FFP candidates, simply by obtaining second epochs 4-8 years after the event.At present, the search for such hosts is restricted to within the ``confusion limit'' of θ_\\confus ˜ 0.25'' but future WFIRST (Wide Field Infrared Survey Telescope) observations will allow one to probe beyond this confusion limit as well.

  9. Free-floating synthetic nanosheets by atomic layer deposition.

    PubMed

    Lee, Kyoungmi; Kim, Do Han; Parsons, Gregory N

    2014-07-23

    Two-dimensional (2D) nanosheets with distinctive properties are often fabricated by exfoliation, hydrothermal synthesis, or vapor-phase reaction. While these approaches are useful to generate nanosheets, we show that free-floating 2D metal oxide flakes with nanometer-scale thickness can also be formed by atomic layer deposition (ALD), where the ALD process allows the thickness and composition to be precisely tuned. In this work, we describe in detail the ALD nanosheet fabrication process and demonstrate how the choice of the sacrificial substrate affects the subsequent ALD processing and the resulting nanosheet thickness and surface structure. In addition, we introduce the fabrication of organic/inorganic bilayer nanosheets with unique potential applications. PMID:24979745

  10. Exometeorology: Characterizing Weather on a Young Free-Floating Planet

    NASA Astrophysics Data System (ADS)

    Biller, Beth

    2015-10-01

    Variability attributed to cloud structure is a persistent feature for L and T type field brown dwarfs. Directly imaged planets occupy the same temperature regime as L and T type brown dwarfs and are likely to be equally variable. As part of our ongoing NTT SOFI survey for variability in young free-floating planets and low mass brown dwarfs, we detect significant variability in a young, free-floating planetary mass object, likely due to rotational modulation of inhomogeneous cloud cover. This is the first such detection in a bonafide planetary mass object -- here we propose for HST and Spitzer followup to pinpoint the source of the observed variability and determine the rotational period of the object. Due to its low surface gravity, while this object has a late L spectral type, it has an ``early/mid T'' Teff<1200 K. We will directly test the effect of low surface gravity on observed variability. If variability matches that found in objects with similar spectral type but higher surface gravity -- i.e. high-level hazes observed in mid L dwarfs by Yang et al. 2015 -- we expect similar variability amplitudes in all bands. If variability is due to inhomogeneous clouds as found in higher gravity T dwarfs with similar Teff (Buenzli et al. 2015, Apai et al. 2013), we expect variability to be strongest in broadband J and H and have lower amplitudes within the 1.4 um water absorption feature (only observable from space). As ground-based searches for brown dwarf variability only have sensitivities to >2-3% variability, we require the proven photometric stability of HST and Spitzer (sensitivity down to <0.5% variability) to be sensitive to small differences between bands.

  11. Constraints on the free-floating planets supporting aqueous life

    NASA Astrophysics Data System (ADS)

    Badescu, Viorel

    2011-11-01

    Optically thick atmospheres provide conditions for life on free-floating planets (FFPs). These atmospheres may ensure conservation of energy released by radio-nuclides and the long-term thermal stability of a necessary life-supporting liquid solvent (e.g. water) on the surface. Not all atmospheric gases allow “reasonable” large opacities. The list of candidate atmospheric gases considered in this paper consists of nitrogen, carbon dioxide, methane and ethane. We show that bodies with water oceans are possible in interstellar space. This may happen on FFPs of (significantly) smaller or larger mass than the Earth. Generally, in case of FFP smaller in size than the Earth, the atmosphere exhibits a mixing layer near the surface and a radiative layer at higher altitudes while the atmosphere of FFPs larger in size than Earth does not exhibit a mixing layer. The prescribed thermodynamic state of water on the surface has some influence on the features of the atmosphere. The atmosphere mass of a life-hosting FFP of Earth size is two or three orders of magnitude larger that the mass of Earth atmosphere. For FFPs larger than the Earth and specific values of surface pressure and temperature, there are conditions for condensation (in the ethane atmosphere) or condensation and deposition (in the carbon dioxide atmosphere). Some arguments induce the conclusion than the associated surface pressures and temperatures should be treated with caution as appropriate life conditions.

  12. Investigating the free-floating planet mass by Euclid observations

    NASA Astrophysics Data System (ADS)

    Hamolli, Lindita; Hafizi, Mimoza; De Paolis, Francesco; Nucita, Achille A.

    2016-08-01

    The detection of anomalies in gravitational microlensing events is nowadays one of the main goals among the microlensing community. In the case of single-lens events, these anomalies can be caused by the finite source effects, that is when the source disk size is not negligible, and by the Earth rotation around the Sun (the so-called parallax effect). The finite source and parallax effects may help to define the mass of the lens, uniquely. Free-floating planets (FFPs) are extremely dim objects, and gravitational microlensing provides at present the exclusive method to investigate these bodies. In this work, making use of a synthetic population algorithm, we study the possibility of detecting the finite source and parallax effects in simulated microlensing events caused by FFPs towards the Galactic bulge, taking into consideration the capabilities of the space-based Euclid telescope. We find a significant efficiency for detecting the parallax effect in microlensing events with detectable finite source effect, that turns out to be about 51 % for mass function index α_{PL} = 1.3.

  13. Free-floating planets from core accretion theory: microlensing predictions

    NASA Astrophysics Data System (ADS)

    Ma, Sizheng; Mao, Shude; Ida, Shigeru; Zhu, Wei; Lin, Douglas N. C.

    2016-09-01

    We calculate the microlensing event rate and typical time-scales for the free-floating planet (FFP) population that is predicted by the core accretion theory of planet formation. The event rate is found to be ˜1.8 × 10-3 of that for the stellar population. While the stellar microlensing event time-scale peaks at around 20 d, the median time-scale for FFP events (˜0.1 d) is much shorter. Our values for the event rate and the median time-scale are significantly smaller than those required to explain the Sumi et al. result, by factors of ˜13 and ˜16, respectively. The inclusion of planets at wide separations does not change the results significantly. This discrepancy may be too significant for standard versions of both the core accretion theory and the gravitational instability model to explain satisfactorily. Therefore, either a modification to the planet formation theory is required or other explanations to the excess of short-time-scale microlensing events are needed. Our predictions can be tested by ongoing microlensing experiment such as Korean Microlensing Telescope Network, and by future satellite missions such as WFIRST and Euclid.

  14. Close encounters involving free-floating planets in star clusters

    NASA Astrophysics Data System (ADS)

    Wang, Long; Kouwenhoven, M. B. N.; Zheng, Xiaochen; Church, Ross P.; Davies, Melvyn B.

    2015-06-01

    Instabilities in planetary systems can result in the ejection of planets from their host system, resulting in free-floating planets (FFPs). If this occurs in a star cluster, the FFP may remain bound to the star cluster for some time and interact with the other cluster members until it is ejected. Here, we use N-body simulations to characterize close star-planet and planet-planet encounters and the dynamical fate of the FFP population in star clusters containing 500-2000 single or binary star members. We find that FFPs ejected from their planetary system at low velocities typically leave the star cluster 40 per cent earlier than their host stars, and experience tens of close (<1000 au) encounters with other stars and planets before they escape. The fraction of FFPs that experiences a close encounter depends on both the stellar density and the initial velocity distribution of the FFPs. Approximately half of the close encounters occur within the first 30 Myr, and only 10 per cent occur after 100 Myr. The periastron velocity distribution for all encounters is well described by a modified Maxwell-Bolzmann distribution, and the periastron distance distribution is linear over almost the entire range of distances considered, and flattens off for very close encounters due to strong gravitational focusing. Close encounters with FFPs can perturb existing planetary systems and their debris structures, and they can result in re-capture of FFPs. In addition, these FFP populations may be observed in young star clusters in imaging surveys; a comparison between observations and dynamical predictions may provide clues to the early phases of stellar and planetary dynamics in star clusters.

  15. A method for combining RNAscope in situ hybridization with immunohistochemistry in thick free-floating brain sections and primary neuronal cultures.

    PubMed

    Grabinski, Tessa M; Kneynsberg, Andrew; Manfredsson, Fredric P; Kanaan, Nicholas M

    2015-01-01

    In situ hybridization (ISH) is an extremely useful tool for localizing gene expression and changes in expression to specific cell populations in tissue samples across numerous research fields. Typically, a research group will put forth significant effort to design, generate, validate and then utilize in situ probes in thin or ultrathin paraffin embedded tissue sections. While combining ISH and IHC is an established technique, the combination of RNAscope ISH, a commercially available ISH assay with single transcript sensitivity, and IHC in thick free-floating tissue sections has not been described. Here, we provide a protocol that combines RNAscope ISH with IHC in thick free-floating tissue sections from the brain and allows simultaneous co-localization of genes and proteins in individual cells. This approach works well with a number of ISH probes (e.g. small proline-rich repeat 1a, βIII-tubulin, tau, and β-actin) and IHC antibody stains (e.g. tyrosine hydroxylase, βIII-tubulin, NeuN, and glial fibrillary acidic protein) in rat brain sections. In addition, we provide examples of combining ISH-IHC dual staining in primary neuron cultures and double-ISH labeling in thick free-floating tissue sections from the brain. Finally, we highlight the ability of RNAscope to detect ectopic DNA in neurons transduced with viral vectors. RNAscope ISH is a commercially available technology that utilizes a branched or "tree" in situ method to obtain ultrasensitive, single transcript detection. Immunohistochemistry is a tried and true method for identifying specific protein in cell populations. The combination of a sensitive and versatile oligonucleotide detection method with an established and versatile protein assay is a significant advancement in studies using free-floating tissue sections.

  16. A Method for Combining RNAscope In Situ Hybridization with Immunohistochemistry in Thick Free-Floating Brain Sections and Primary Neuronal Cultures

    PubMed Central

    Grabinski, Tessa M.; Kneynsberg, Andrew; Manfredsson, Fredric P.; Kanaan, Nicholas M.

    2015-01-01

    In situ hybridization (ISH) is an extremely useful tool for localizing gene expression and changes in expression to specific cell populations in tissue samples across numerous research fields. Typically, a research group will put forth significant effort to design, generate, validate and then utilize in situ probes in thin or ultrathin paraffin embedded tissue sections. While combining ISH and IHC is an established technique, the combination of RNAscope ISH, a commercially available ISH assay with single transcript sensitivity, and IHC in thick free-floating tissue sections has not been described. Here, we provide a protocol that combines RNAscope ISH with IHC in thick free-floating tissue sections from the brain and allows simultaneous co-localization of genes and proteins in individual cells. This approach works well with a number of ISH probes (e.g. small proline-rich repeat 1a, βIII-tubulin, tau, and β-actin) and IHC antibody stains (e.g. tyrosine hydroxylase, βIII-tubulin, NeuN, and glial fibrillary acidic protein) in rat brain sections. In addition, we provide examples of combining ISH-IHC dual staining in primary neuron cultures and double-ISH labeling in thick free-floating tissue sections from the brain. Finally, we highlight the ability of RNAscope to detect ectopic DNA in neurons transduced with viral vectors. RNAscope ISH is a commercially available technology that utilizes a branched or “tree” in situ method to obtain ultrasensitive, single transcript detection. Immunohistochemistry is a tried and true method for identifying specific protein in cell populations. The combination of a sensitive and versatile oligonucleotide detection method with an established and versatile protein assay is a significant advancement in studies using free-floating tissue sections. PMID:25794171

  17. Chemokine-Mediated Migration of Mesencephalic Neural Crest Cells

    PubMed Central

    Rezzoug, Francine; Seelan, Ratnam S.; Bhattacherjee, Vasker; Greene, Robert M.; Pisano, M. Michele

    2011-01-01

    Clefts of the lip and/or palate are among the most prevalent birth defects affecting approximately 7000 newborns in the United States annually. Disruption of the developmentally programmed migration of neural crest cells (NCCs) into the orofacial region is thought to be one of the major causes of orofacial clefting. Signaling of the chemokine SDF-1 (Stromal Derived Factor-1) through its specific receptor, CXCR4, is required for the migration of many stem cell and progenitor cell populations from their respective sites of emergence to the regions where they differentiate into complex cell types, tissues and organs. In the present study, “transwell” assays of chick embryo mesencephalic (cranial) NCC migration and ex ovo whole embryo “bead implantation” assays were utilized to determine whether SDF-1/CXCR4 signaling mediates mesencephalic NCC migration. Results from this study demonstrate that attenuation of SDF-1 signaling, through the use of specific CXCR4 antagonists (AMD3100 and TN14003), disrupts the migration of mesencephalic NCCs into the orofacial region, suggesting a novel role for SDF-1/CXCR4 signaling in the directed migration of mesencephalic NCCs in the early stage embryo. PMID:22015108

  18. Phytoremediation of Hg and Cd from industrial effluents using an aquatic free floating macrophyte Azolla pinnata.

    PubMed

    Rai, Prabhat Kumar

    2008-01-01

    The level of heavy metal pollution in Singrauli, an industrial region in India, was assessed and the phytoremediation capacity of a small water fern, Azolla pinnata R.BR (Azollaceae), was observed to purify waters polluted by two heavy metals, i.e., mercury (Hg) and cadmium (Cd) under a microcosm condition. Azolla pinnata is endemic to India and is an abundant and easy-growing free-floating water fern usually found in the rice fields, polluted ponds, and reservoirs of India. The fern was grown in 24 40-L aquariums containing Hg2+ and Cd2+ ions each in concentrations of 0.5, 1.0, and 3.0 mgL(-1) during the course of this study. The study revealed an inhibition of Azolla pinnata growth by 27.0-33.9% with the highest in the presence of Hg (II) ions at 0.5 mgL(-1) in comparison to the control After 13 days of the experiment, metal contents in the solution were decreased up to 70-94%. In the tissues of Azolla pinnata, the concentration of selected heavy metals during investigation was recorded between 310 and 740 mgKg(-1) dry mass, with the highest levelfoundfor Cd (II) treatment at 3.0 mgL(-1) containing a metal solution. PMID:19260224

  19. On the nature of control algorithms for free-floating space manipulators

    NASA Technical Reports Server (NTRS)

    Papadopoulos, Evangelos; Dubowsky, Steven

    1991-01-01

    It is suggested that nearly any control algorithm that can be used for fixed-based manipulators also can be employed in the control of free-floating space manipulator systems, with the additional conditions of estimating or measuring a spacecraft's orientation and of avoiding dynamic singularities. This result is based on the structural similarities between the kinematic and dynamic equations for the same manipulator but with a fixed base. Barycenters are used to formulate the kinematic and dynamic equations of free-floating space manipulators. A control algorithm for a space manipulator system is designed to demonstrate the value of the analysis.

  20. Motion planning for redundant prismatic-jointed manipulators in the free-floating mode

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Dong; Baoyin, He-Xi; Ma, Xing-Rui

    2012-10-01

    This paper investigates the motion planning of redundant free-floating manipulators with seven prismatic joints. On the earth, prismatic-jointed manipulators could only position their end-effectors in a desired way. However, in space, the end-effectors of free-floating manipulators can achieve both the desired orientation and desired position due to the dynamical coupling between manipulator and satellite movement, which is formally expressed by linear and angular momentum conservation laws. In this study, a tractable algorithm particle swarm optimization combined with differential evolution (PSODE) is provided to deal with the motion planning of redundant free-floating prismatic-jointed manipulators, which could avoid the pseudo inverse of the Jacobian matrix. The polynomial functions, as argument in sine functions are used to specify the joint paths. The coefficients of the polynomials are optimized to achieve the desired end-effector orientation and position, and simultaneously minimize the unit-mass-kinetic energy using the redundancy. Relevant simulations prove that this method provides satisfactory smooth paths for redundant free-floating prismatic-jointed manipulators. This study could help to recognize the advantages of redundant prismatic-jointed space manipulators.

  1. Tuberculous pericarditis presenting as multiple free floating masses in pericardial effusion.

    PubMed

    Yoon, Shin-Ae; Hahn, Youn-Soo; Hong, Jong Myeon; Lee, Ok-Jun; Han, Heon-Seok

    2012-03-01

    Pericarditis is a rare manifestation of tuberculosis (Tb) in children. A 14-yr-old Korean boy presented with cardiac tamponade during treatment of pulmonary tuberculosis. He developed worsening anemia and persistent fever in spite of anti-tuberculosis medications. Echocardiography found free floating multiple discoid masses in the pericardial effusion. The masses and exudates were removed by pericardiostomy. The masses were composed of pink, amorphous meshwork of threads admixed with degenerated red blood cells and leukocytes with numerous acid-fast bacilli, which were confirmed as Mycobacterium species by polymerase chain reaction. The persistent fever and anemia were controlled after pericardiostomy. This is the report of a unique manifestation of Tb pericarditis as free floating masses in the effusion with impending tamponade.

  2. a Theoretical Calculation of Microlensing Signatures Caused by Free-Floating Planets Towards the Galactic Bulge

    NASA Astrophysics Data System (ADS)

    Hamolli, L.; Hafizi, M.; Nucita, A. A.

    2013-08-01

    Free-floating planets (FFPs) are recently drawing a special interest of the scientific community. Gravitational microlensing is up to now the exclusive method for the investigation of FFPs, including their spatial distribution function and mass function. In this paper, we examine the possibility that the future Euclid space-based observatory may allow to discover a substantial number of microlensing events caused by FFPs. Based on latest results about the free-floating planet (FFP) mass function in the mass range [10-5, 10-2]M⊙, we calculate the optical depth towards the Galactic bulge as well as the expected microlensing rate and find that Euclid may be able to detect hundreds to thousands of these events per month. Making use of a synthetic population, we also investigate the possibility of detecting parallax effect in simulated microlensing events due to FFPs and find a significant efficiency for the parallax detection that turns out to be around 30%.

  3. Trajectory planning of free-floating space robot using Particle Swarm Optimization (PSO)

    NASA Astrophysics Data System (ADS)

    Wang, Mingming; Luo, Jianjun; Walter, Ulrich

    2015-07-01

    This paper investigates the application of Particle Swarm Optimization (PSO) strategy to trajectory planning of the kinematically redundant space robot in free-floating mode. Due to the path dependent dynamic singularities, the volume of available workspace of the space robot is limited and enormous joint velocities are required when such singularities are met. In order to overcome this effect, the direct kinematics equations in conjunction with PSO are employed for trajectory planning of free-floating space robot. The joint trajectories are parametrized with the Bézier curve to simplify the calculation. Constrained PSO scheme with adaptive inertia weight is implemented to find the optimal solution of joint trajectories while specific objectives and imposed constraints are satisfied. The proposed method is not sensitive to the singularity issue due to the application of forward kinematic equations. Simulation results are presented for trajectory planning of 7 degree-of-freedom (DOF) redundant manipulator mounted on a free-floating spacecraft and demonstrate the effectiveness of the proposed method.

  4. Hosted and free-floating metal-bearing atmospheric nanoparticles in Mexico City.

    PubMed

    Adachi, Kouji; Buseck, Peter R

    2010-04-01

    Nanoparticles (NPs) are ubiquitous in the atmosphere. Because of their small sizes, they can travel deeply into the lungs and other parts of the body. Many are highly reactive which, combined with their large surface areas, means they can seriously affect human health. Their occurrences in the atmosphere and their biological effects are not well-understood. We focus on NPs that were either free-floating or hosted within large aerosol particles (aerodynamic diameter 50-300 nm) and consist of or contain transition or post-transition metals (m-NPs). The samples were collected from ambient air above Mexico City (MC). We used transmission electron microscopy to measure their sizes and compositions. More than half of the 572 m-NPs that we analyzed contain two or more metals, and Fe, Pb, or Zn occurs in more than 60%. Hg occurs in 21% and is especially abundant in free-floating m-NPs. We find that m-NPs are common in polluted air such as in the MC area and, by inference, presumably other megacities. The range and variety of compositions of m-NPs that we encountered, whether free-floating or hosted within larger aerosol particles, indicate the complicated occurrences that should be considered when evaluating the health effects of m-NPs in complex urban areas.

  5. A system architecture for long duration free floating flight for military applications

    SciTech Connect

    Epley, L.E. )

    1990-08-31

    Accessibility is today's space frontier. Our need for wide-band global communications, earth imaging an sensing, atmospheric measurements and military reconnaissance is endless but growing dependence on space-based systems raises concerns about potential vulnerability. Military commanders want space assets more accessible and under direct local control. As a result, a robust and low cost access to space-like capability has become a national priority. Buoyant vehicles, free floating in the middle stratosphere could provide the kind of cost effective access to space-like capability needed for a verity of missions. These vehicles are inexpensive, invisible and easily launched. Developments in payload electronics, atmospheric wind modeling and materials combined with ever-improving communications and navigation infrastructure are making balloon-borne concepts more attractive. The fundamental question is whether a free floating balloon, used in a pseudo-satellite role, has value in a military system. Flight tests are ongoing under NASA sponsorship. Following these tests NASA intends to use the vehicles for research in the Antarctic. The concept is being reviewed by other agencies interested in stratospheric research. We believe that LDFFF systems have applications in areas of communications, surveillance and other traditional satellite missions. Dialogue with the broader community of space users is needed to expand the applications. This report reviews the status of the recent flight tests and presents an overview of the concept of Long Duration Free Floating Flight for military applications. 12 refs., 13 figs.

  6. Trophic and tropic effects of striatal astrocytes on cografted mesencephalic dopamine neurons and their axons.

    PubMed

    Pierret, P; Quenneville, N; Vandaele, S; Abbaszadeh, R; Lanctôt, C; Crine, P; Doucet, G

    1998-01-01

    Astrocytes from the ventral mesencephalon and from the striatum respectively promote the dendritic and axonal arborization of dopamine (DA) neurons in vitro. To test this response in vivo, astrocytes in primary cultures from the neonatal cerebral cortex, ventral mesencephalon, or striatum were coimplanted with fetal ventral mesencephalic tissue into the intact or DA-denervated striatum of adult rats and these cografts examined after 3-6 months by tyrosine hydroxylase (TH) immunohistochemistry (intact recipients) or after 5-6 months by in vitro [3H]DA-uptake autoradiography (DA-denervated recipients). In contrast with single ventral mesencephalic grafts, all types of cograft displayed a rather uniform distribution of TH-immunoreactive perikarya. The average size of TH-immunoreactive cell bodies was not significantly different in cografts containing cortical or mesencephalic astrocytes and in single ventral mesencephalic grafts, but it was significantly larger in cografts containing striatal astrocytes. Nevertheless, the number of [3H]DA-labeled terminals in the DA-lesioned host striatum was clearly smaller with cografts of striatal astrocytes than with single mesencephalic grafts or with cografts containing cortical astrocytes. On the other hand, cografts of striatal astrocytes contained much higher numbers of [3H]DA-labeled terminals than the other types of graft or cograft. Thus, while cografted astrocytes in general influence the distribution of DA neurons within the graft, astrocytes from the neonatal striatum have a trophic effect on DA perikarya and a tropic effect on DA axons, keeping the latter within the graft.

  7. Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River

    USGS Publications Warehouse

    Houser, Jeff N.; Giblin, Shawn M.; James, William F.; Langrehr, H.A.; Rogala, James T.; Sullivan, John F.; Gray, Brian R.

    2013-01-01

    River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi River (UMR) that varied in connectivity to the channel. Greater connectivity was associated with higher water column nitrate (NO3-N) concentration, higher rates of sediment phosphorus (P) release, and higher rates of NO3-N flux to the sediments. Rates of sediment P and N (as NH4-N) release were similar to those of eutrophic lakes. Water column nutrient concentrations were high, and FFP tissue was nutrient rich suggesting that the eutrophic condition of the UMR often facilitated abundant FFP. However, tissue nutrient concentrations, and the associations between FFP biomass and water column nutrient concentrations, suggested that nutrients constrained FFP abundance at some sites. FFP abundance was positively associated with SAV abundance and negatively associated with dissolved oxygen concentration. These results illustrate important connections among hydraulic connectivity, nutrient cycling, FFP, SAV, and DO in the backwaters of a large, floodplain river.

  8. DETECTABILITY OF FREE FLOATING PLANETS IN OPEN CLUSTERS WITH THE JAMES WEBB SPACE TELESCOPE

    SciTech Connect

    Pacucci, Fabio; Ferrara, Andrea; D'Onghia, Elena

    2013-12-01

    Recent observations have shown the presence of extra-solar planets in Galactic open stellar clusters, such as in Praesepe (M44). These systems provide a favorable environment for planetary formation due to the high heavy-element content exhibited by the majority of their population. The large stellar density, and corresponding high close-encounter event rate, may induce strong perturbations of planetary orbits with large semimajor axes. Here we present a set of N-body simulations implementing a novel scheme to treat the tidal effects of external stellar perturbers on planetary orbit eccentricity and inclination. By simulating five nearby open clusters, we determine the rate of occurrence of bodies extracted from their parent stellar system by quasi-impulsive tidal interactions. We find that the specific free-floating planet production rate N-dot {sub o} (total number of free-floating planets per unit of time, normalized by the total number of stars), is proportional to the stellar density ρ{sub *} of the cluster: N-dot {sub o}=αρ{sub ⋆}, with α = (23 ± 5) × 10{sup –6} pc{sup 3} Myr{sup –1}. For the Pleiades (M45), we predict that ∼26% of stars should have lost their planets. This raises the exciting possibility of directly observing these wandering planets with the James Webb Space Telescope in the near-infrared band. Assuming a surface temperature for the planet of ∼500 K, a free-floating planet of Jupiter size inside the Pleiades would have a specific flux of F {sub ν} (4.4 μm) ≈4 × 10{sup 2} nJy, which would lead to a very clear detection (S/N ∼ 100) in only one hour of integration.

  9. Estimating the center of mass of a free-floating body in microgravity.

    PubMed

    Lejeune, L; Casellato, C; Pattyn, N; Neyt, X; Migeotte, P-F

    2013-01-01

    This paper addresses the issue of estimating the position of the center of mass (CoM) of a free-floating object of unknown mass distribution in microgravity using a stereoscopic imaging system. The method presented here is applied to an object of known mass distribution for validation purposes. In the context of a study of 3-dimensional ballistocardiography in microgravity, and the elaboration of a physical model of the cardiovascular adaptation to weightlessness, the hypothesis that the fluid shift towards the head of astronauts induces a significant shift of their CoM needs to be tested. The experiments were conducted during the 57th parabolic flight campaign of the European Space Agency (ESA). At the beginning of the microgravity phase, the object was given an initial translational and rotational velocity. A 3D point cloud corresponding to the object was then generated, to which a motion-based method inspired by rigid body physics was applied. Through simulations, the effects of the centroid-to-CoM distance and the number of frames of the sequence are investigated. In experimental conditions, considering the important residual accelerations of the airplane during the microgravity phases, CoM estimation errors (16 to 76 mm) were consistent with simulations. Overall, our results suggest that the method has a good potential for its later generalization to a free-floating human body in a weightless environment.

  10. Space structure capturing and assembling by experimental free-floating robot satellite (EFFORTS) simulators

    NASA Astrophysics Data System (ADS)

    Yoshida, K.

    1993-09-01

    In order to study and validate practical availability of control schemes for in-orbit operational free-floating robots, a research group at the Tokyo Institute of Technology has developed the Experimental Free-FlOating RoboT Satellite (EFFORTS-I and II) simulators, which enable to examine 2-dimensional pseudo-micro gravity motion dynamics by air lift system. The robot model comprising a satellite base body and articulated manipulator arms with grippers and wrist force sensors, makes horizontal motion without mechanical disturbances or external forces. This paper presents the control methods and experimental results for spacecraft/manipulator control paying attention to the reaction dynamics, and assembly and deployment operation of space structures. The paper focuses the discussion of (1) hardware design of EFFORTS simulators, (2) dynamic modeling and a basic control concept for space free-floating manipulators, (3) satellite attitude control coordinating with manipulator dynamics, (4) practical force control for dexterous manipulation, and (5) experimental results on above topics.

  11. [A Case of Carotid Free-Floating Thrombus Treated by Carotid Ultrasonography-Guided Endovascular Approach].

    PubMed

    Otawa, Masato; Kinkori, Takeshi; Watanabe, Kenichi; Ando, Ryo; Tambara, Masao; Arima, Toru

    2016-06-01

    We experienced a case of carotid free-floating thrombus treated by carotid ultrasonography-guided endovascular approach. A 63-year-old man was brought to our hospital with the chief complaint of sudden onset left hemiplegia. MRI revealed acute infarction of the right MCA territory due to the right M1 occlusion. Carotid ultrasonography showed a pedunculated, polypoid mobile plaque floating with the cardiac beat. We attempted ultrasonography-guided endovascular treatment. Under proximal balloon protection, the floating plaque was successfully aspirated into the Penumbra aspiration catheter. Carotid stent was also placed to stabilize the residual pedicle of the plaque. Aspirated plaque was identified as fresh thrombus by pathological examination. Carotid ultrasonography-guided endovascular approach was effective for getting the picture of real-time dynamics of the carotid FFT. PMID:27270147

  12. On the concept of sloped motion for free-floating wave energy converters

    PubMed Central

    Payne, Grégory S.; Pascal, Rémy; Vaillant, Guillaume

    2015-01-01

    A free-floating wave energy converter (WEC) concept whose power take-off (PTO) system reacts against water inertia is investigated herein. The main focus is the impact of inclining the PTO direction on the system performance. The study is based on a numerical model whose formulation is first derived in detail. Hydrodynamics coefficients are obtained using the linear boundary element method package WAMIT. Verification of the model is provided prior to its use for a PTO parametric study and a multi-objective optimization based on a multi-linear regression method. It is found that inclining the direction of the PTO at around 50° to the vertical is highly beneficial for the WEC performance in that it provides a high capture width ratio over a broad region of the wave period range. PMID:26543397

  13. Collisions of Free-floating Planets with Evolved Stars in Globular Clusters

    NASA Astrophysics Data System (ADS)

    Soker, Noam; Rappaport, Saul; Fregeau, John

    2001-12-01

    We estimate the rate of collisions between stars and free-floating planets (FFPs) in globular clusters, in particular, the collision of FFPs with red giant branch (RGB) stars. Recent dynamical simulations imply that the density of such objects could exceed ~106 pc-3 near the cores of rich globular clusters. We show that in these clusters ~5%-10% of all RGB stars near the core would suffer a collision with an FFP and that such a collision can spin up the RGB star's envelope by an order of magnitude. In turn, the higher rotation rates may lead to enhanced mass-loss rates on the RGB, which could result in bluer horizontal branch (HB) stars. Hence, it is plausible that the presence of a large population of FFPs in a globular cluster can influence the distribution of stars on the HB of that cluster to a detectable degree.

  14. Planet-planet scattering alone cannot explain the free-floating planet population

    NASA Astrophysics Data System (ADS)

    Veras, Dimitri; Raymond, Sean N.

    2012-03-01

    Recent gravitational microlensing observations predict a vast population of free-floating giant planets that outnumbers main-sequence stars almost twofold. A frequently invoked mechanism for generating this population is a dynamical instability that incites planet-planet scattering and the ejection of one or more planets in isolated main-sequence planetary systems. Here, we demonstrate that this process alone probably cannot represent the sole source of these Galactic wanderers. By using straightforward quantitative arguments and N-body simulations, we argue that the observed number of exoplanets exceeds the plausible number of ejected planets per system from scattering. Thus, other potential sources of free floaters, such as planetary stripping in stellar clusters and post-main-sequence ejection, must be considered.

  15. Diencephalic-Mesencephalic Junction Dysplasia: A Novel Recessive Brain Malformation

    ERIC Educational Resources Information Center

    Zaki, Maha S.; Saleem, Sahar N.; Dobyns, William B.; Barkovich, A. James; Bartsch, Hauke; Dale, Anders M.; Ashtari, Manzar; Akizu, Naiara; Gleeson, Joseph G.; Grijalvo-Perez, Ana Maria

    2012-01-01

    We describe six cases from three unrelated consanguineous Egyptian families with a novel characteristic brain malformation at the level of the diencephalic-mesencephalic junction. Brain magnetic resonance imaging demonstrated a dysplasia of the diencephalic-mesencephalic junction with a characteristic "butterfly"-like contour of the midbrain on…

  16. Masses and Multiplicity of Nearby Free- floating Methane and L Dwarfs

    NASA Astrophysics Data System (ADS)

    Brandner, Wolfgang

    2000-07-01

    Brown dwarfs never stabilize themselves on the hydrogen main sequence, thus there is an ambiguity between the temperature or luminosity of a given object and its mass or age. In order to test the mass-luminosity relations of {still uncertain} evolutionary models, a direct dynamical determination of mass is required. As a first step towards a dynamical mass estimate for brown dwarfs, we have compiled a sample of 50 very-low-mass objects {M<=0.08M_sun} in the solar neighborhood {distances 5 pc to 30 pc} with spectral types of L0 and later {including several dwarfs with Methane absorption bands in their atmospheres}. Using WFPC2, we propose to observe these objects in two filter bands with the aim to identify close companions, measure their colors, and to obtain first epoch data of the newly discovered binaries. We show that the closest binary brown dwarfs we can resolve will have orbital periods between 3 and 10 yr. Hence, within a few years we should be able to very accurately pin down masses for brown dwarfs and to calibrate evolutionary tracks. Binary properties like multiplicity, distribution of binary separations and brightness ratios hold clues on the origin of free-floating brown dwarf binaries. Our program will be an important step towards a better understanding of the still elusive class of brown dwarfs.

  17. Using Dynamical Models to Predict the Terrestrial-Mass Free-Floating Planet Population

    NASA Astrophysics Data System (ADS)

    Barclay, Thomas; Quintana, Elisa V.

    2016-10-01

    In the classical picture of planet formation, planets form within circumstellar disks as a product of star formation. The material in the disk either forms into a planet, remains bound to the star, falls into the star, or is ejected from the system. We explore the properties of this ejected material using N-body simulations of the late stages of terrestrial planet formation. We find that in planetary systems like ours (with Jupiter and Saturn) about half the ejected material is in bodies less massive than the Moon and half is in bodies more massive than Mars. No planets more massive than half an Earth-mass, however, were ejected, primarily because most of the ejections occur before the timescales needed to grow an Earth-mass body. Without giant planets present in the system, very little material is ever ejected. We predict that future space-borne microlensing searches for free-floating terrestrial-mass planets, such as WFIRST, will discover large numbers of Mars-mass planets but will not make significant detections of Earth-mass planets.

  18. Using Planet Formation Simulations to Predict the Free-floating Planet Yield Expected from WFIRST

    NASA Astrophysics Data System (ADS)

    Barclay, Thomas; Quintana, Elisa V.

    2016-06-01

    Planets are thought to form in circumstellar disks as a product of star formation. Material in the disk ends up in one of three places, (a) it remains in the disk as part of a planet, minor body or as interplanetary material, (b) it falls into the star, or (c) it is ejected from the system. We explore the properties of this ejected material using N-body simulations. We find that in planetary systems like ours (with Jupiter and Saturn) about half the ejected material is in bodies smaller than 1 Lunar-mass and about half is in bodies larger than 1 Mars-mass. The ejections happen early and no planets more massive than half an earth-mass are ejected. When no giant planets are present in the system, very little material is ejected. We predict that future space-borne microlensing searches for free-floating terrestrial-mass planets, such as WFIRST, will discover large numbers of Mars-mass planets but will not make significant detections of Earth-mass planets.

  19. ARE LARGE, COMETARY-SHAPED PROPLYDS REALLY (FREE-FLOATING) EVAPORATING GAS GLOBULES?

    SciTech Connect

    Sahai, R.; Guesten, R.; Morris, M. R.

    2012-12-20

    We report the detection of strong and compact molecular line emission (in the CO J = 3-2, 4-3, 6-5, 7-6, {sup 13}CO J = 3-2, HCN, and HCO{sup +} J = 4-3 transitions) from a cometary-shaped object (Carina-frEGG1) in the Carina star-forming region (SFR) previously classified as a photoevaporating protoplanetary disk (proplyd). We derive a molecular mass of 0.35 M{sub Sun} for Carina-frEGG1, which shows that it is not a proplyd, but belongs to a class of free-floating evaporating gas globules (frEGGs) recently found in the Cygnus SFR by Sahai et al. Archival adaptive optics near-IR (Ks) images show a central hourglass-shaped nebula. The derived source luminosity (about 8-18 L{sub Sun }), the hourglass morphology, and the presence of collimated jets seen in Hubble Space Telescope images imply the presence of a jet-driving, young, low-mass star deeply embedded in the dust inside Carina-frEGG1. Our results suggest that the true nature of many or most such cometary-shaped objects seen in massive SFRs and previously labeled as proplyds has been misunderstood, and that these are really frEGGs.

  20. Thermodynamic Constrains for Life Based on Non-Aqueous Polar Solvents on Free-Floating Planets

    NASA Astrophysics Data System (ADS)

    Badescu, Viorel

    2011-02-01

    Free-floating planets (FFPs) might originate either around a star or in solitary fashion. These bodies can retain molecular gases atmospheres which, upon cooling, have basal pressures of tens of bars or more. Pressure-induced opacity of these gases prevents such a body from eliminating its internal radioactive heat and its surface temperature can exceed for a long term the melting temperature of a life-supporting solvent. In this paper two non-aqueous but still polar solvents are considered: hydrogen sulfide and ammonia. Thermodynamic requirements to be fulfilled by a hypothetic gas constituent of a life-supporting FFP's atmosphere are studied. The three gases analyzed here (nitrogen, methane and ethane) are candidates. We show that bodies with ammonia oceans are possible in interstellar space. This may happen on FFPs of (significantly) smaller or larger mass than the Earth. Generally, in case of FFP smaller in size than the Earth, the atmosphere exhibits a convective layer near the surface and a radiative layer at higher altitudes while the atmosphere of FFPs larger in size than Earth does not exhibit a convective layer. The atmosphere mass of a life-hosting FFP of Earth size is two or three orders of magnitude larger than the mass of Earth atmosphere. For FFPs larger than the Earth and specific values of surface pressure and temperature, there are conditions for condensation (in the ethane atmosphere). Some arguments induce the conclusion than the associated surface pressures and temperatures should be treated with caution as appropriate life conditions.

  1. Thermodynamic constrains for life based on non-aqueous polar solvents on free-floating planets.

    PubMed

    Badescu, Viorel

    2011-02-01

    Free-floating planets (FFPs) might originate either around a star or in solitary fashion. These bodies can retain molecular gases atmospheres which, upon cooling, have basal pressures of tens of bars or more. Pressure-induced opacity of these gases prevents such a body from eliminating its internal radioactive heat and its surface temperature can exceed for a long term the melting temperature of a life-supporting solvent. In this paper two non-aqueous but still polar solvents are considered: hydrogen sulfide and ammonia. Thermodynamic requirements to be fulfilled by a hypothetic gas constituent of a life-supporting FFP's atmosphere are studied. The three gases analyzed here (nitrogen, methane and ethane) are candidates. We show that bodies with ammonia oceans are possible in interstellar space. This may happen on FFPs of (significantly) smaller or larger mass than the Earth. Generally, in case of FFP smaller in size than the Earth, the atmosphere exhibits a convective layer near the surface and a radiative layer at higher altitudes while the atmosphere of FFPs larger in size than Earth does not exhibit a convective layer. The atmosphere mass of a life-hosting FFP of Earth size is two or three orders of magnitude larger than the mass of Earth atmosphere. For FFPs larger than the Earth and specific values of surface pressure and temperature, there are conditions for condensation (in the ethane atmosphere). Some arguments induce the conclusion than the associated surface pressures and temperatures should be treated with caution as appropriate life conditions.

  2. Free floating ventricular shunt catheter between lateral ventricles: a case report of an unusual ventriculoperitoneal shunt complication.

    PubMed

    Erol, Fatih Serhat; Cakin, Hakan; Ozturk, Sait; Donmez, Osman; Kaplan, Metin

    2013-01-01

    Ventriculoperitoneal (VP) shunt proximal tip disconnection is rarely seen as a shunt complication. Shunt dysfunction and hydrocephaly can develop due to this disconnection. Presented here is a case of a disconnection of the ventricular catheter from the shunt valve, which passed between both lateral ventricles by free floating in the brain CT. The patient was operated on for hydrocephaly. The dysfunctional shunt valve and peritoneal catheter were removed and a new VP shunt system was implemented. Although some publications report that the ventricular catheter can be disconnected from the shunt valve, can adhere to the intraventricular structures, and can be a source of infection, no studies similar to the current case were found in the literature reporting a free floating ventricular catheter between the lateral ventricles.

  3. [In vitro viability and glutathione levels in mesencephalic neurons after seven days hibernation].

    PubMed

    De La Cuétara-Bernal, K; Castillo-Díaz, L; Cruz-Aguado, R; González-Mena, Y; García-Varona, A Y

    In embryonic mesencephalic transplant in patients with Parkinson s disease dopaminergic survival is low (5 10%), and for this reason the use of multiple donors has been considered. The difficulty of obtaining more tissue determines the need for a procedure that enables human nigral tissue to be stored for a time without affecting its physiological state in any significant way. This study was designed to determine whether hibernation of tissue fragments has any influence on viability, how the viability of the mesencephalic cells behaves after 7 days hibernation and the glutathione levels in the hibernated tissue (HT). The viability of the HT in pieces (82.37 2.12) was found to be higher than the value for the whole mesencephalon (70.29 3.43). Viability of the HT, seven days at 4 C, at different post dissociation times, did not differ significantly. Despite the significant differences found between hibernated and fresh tissue at t= 0, this procedure does not seem to affect the mesencephalic tissue in any significant way, as it conserved a 94% viability after hibernation. No evidence was found of increased glutathione content as an antioxidizing response to the damage that might be caused by hibernation. These results suggest that since hibernation does not have any significant effect on the state of the cells it could be considered a useful procedure for conserving tissue to be used in clinical transplants. Moreover, further research is needed on survival and functionality of hibernated cells after being transplanted into animal models in order to evaluate their potential for use in cell therapy.

  4. Shocked and Scorched - Free-Floating Evaporating Gas Globules and Star Formation

    NASA Astrophysics Data System (ADS)

    Sahai, Raghvendra; Morris, Mark R.; Claussen, Mark J.

    2014-07-01

    Massive stars have a strong feedback effect on their environment, via their winds, UV radiation, and ultimately, supernova blast waves, all of which can alter the likelihood for the formation of stars in nearby clouds and limit the accretion process of nearby protostars. Free-floating Evaporating Gaseous Globules, or frEGGs, are a newly recognized class of stellar nurseries embedded within the giant HII regions found in massive star-formation region (MSFRs). We recently discovered the prototype frEGG in the Cygnus MSFR with HST. Further investigation using the Spitzer and Herschel archives have revealed a much larger number (>50) in Cygnus and other MSFRs. Our molecular-line observations of these show the presence of dense clouds with total masses of cool molecular gas exceeding 0.5 to a few Msun associated with these objects, thereby disproving the initial hypothesis based on their morphology that these have an origin similar to the proplyds (cometary-shaped photoevaporating protoplanetary disks) found in Orion. We report the results of our molecular-line studies and detailed high-resolution optical (with HST) or near-IR (with AO at the Keck Observatory) imaging of a few frEGGs in Cygnus, Carina and the W5 MSFRs. The images show the presence of young stars with associated outflow cavities and/or jets in the heads of the tadpole-shaped frEGGs. These results support our hypothesis that frEGGs are density concentrations originating in giant molecular clouds, that, when subject to the compression by the strong winds and ionization from massive stars in these MSFRs, become active star-forming cores. In summary, by virtue of their distinct, isolated morphologies, frEGGs offer us a clean probe of triggered star formation on small scales in the vicinity of massive stars.

  5. Shocked and Scorched: Free-Floating Evaporating Gas Globules and Star Formation in Cygnus

    NASA Astrophysics Data System (ADS)

    Sahai, Raghvendra; Claussen, M. J.; Morris, M. R.

    2012-05-01

    We report molecular line observations of a new class of Free-floating Evaporating Gas Globules with tadpole shapes (i.e., FrEGGs), recently discovered in the Cygnus star-forming region. We serendipitously found two of these in an HST imaging survey, including one of the most prominent members of this class (IRAS20324+4057: the Tadpole). Our molecular-line observations, carried out with the Arizona Radio Observatory's mm-wave telescopes, include on-the-fly maps in the CO and 13CO J=2-1 lines as well as pointed observations in the J=3-2 line of the high-density tracers HCO+ and N2H+. These data show the presence of dense molecular cores with total masses of cold molecular gas exceeding one to a few Msun in almost all FrEGGs. Our radio continuum imaging of 3 FrEGGs, as well as Halpha images from the IPHAS survey reveal bright photo-ionized peripheries around these objects. We infer that FrEGGs are dense, star-forming molecular cores that originated in the Cygnus cloud and are now being photoevaporated by the ultraviolet radiation field of the Cyg OB2 cluster, and shaped by the ram pressure of strong wind sources. The extended tails in some of the largest objects show wiggles likely resulting from Kelvin-Helmoltz instabilities. We find evidence for non-thermal radio emission in the Tadpole, with the radio emission peaking strongly along the shock/ionization front at its head, possibly as a result of a compressed magnetic layer in this front that is interacting with cosmic rays associated with the Cyg OB2 association.

  6. THE COLDEST BROWN DWARF (OR FREE-FLOATING PLANET)?: THE Y DWARF WISE 1828+2650

    SciTech Connect

    Beichman, C.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Marsh, Kenneth A.; Barman, Travis S.; Cushing, Michael C.; Wright, E. L.

    2013-02-10

    We have monitored the position of the cool Y dwarf WISEPA J182831.08+265037.8 using a combination of ground- and space-based telescopes and have determined its distance to be 11.2{sup +1.3} {sub -1.0} pc. Its absolute H magnitude, M{sub H} = 22.21{sup +0.25} {sub -0.22} mag, suggests a mass in the range 0.5-20 M {sub Jup} for ages of 0.1-10 Gyr with an effective temperature in the range 250-400 K. The broad range in mass is due primarily to the unknown age of the object. Since the high tangential velocity of the object, 51 {+-} 5 km s{sup -1}, is characteristic of an old disk population, a plausible age range of 2-4 Gyr leads to a mass range of 3-6 M {sub Jup} based on fits to the (highly uncertain) COND evolutionary models. The range in temperature is due to the fact that no single model adequately represents the 1-5 {mu}m spectral energy distribution (SED) of the source, failing by factors of up to five at either the short or long wavelength portions of the SED. The appearance of this very cold object may be affected by non-equilibrium chemistry or low temperature condensates forming clouds, two atmospheric processes that are known to be important in brown dwarf atmospheres but have proven difficult to model. Finally, we argue that there would have to be a very steep upturn in the number density of late-type Y-dwarfs to account for the putative population of objects suggested by recent microlensing observations. Whether WISE 1828+2650 sits at the low-mass end of the brown dwarf population or is the first example of a large number of 'free-floating' planets is not yet known.

  7. CONFIGURATIONS OF BOUNDED AND FREE-FLOATING PLANETS IN VERY YOUNG OPEN CLUSTERS

    SciTech Connect

    Liu Huigen; Zhang Hui; Zhou Jilin

    2013-08-01

    Open clusters (OCs) are usually young and suitable for studying the formation and evolution of planetary systems. So far, only four planets have been found with radial velocity measurements in OCs. Meanwhile, a lot of free-floating planets (FFPs) have been detected. We utilize N-body simulations to investigate the evolution and final configurations of multi-planetary systems in very young open clusters with an age <10 Myr. After an evolution of 10 Myr, 61%-72% of the planets remain bounded and more than 55% of the planetary systems will maintain their initial orbital configurations. For systems with one planet ejected, more than 25% of them have the surviving planets in misaligned orbits. In the clusters, the fraction of planetary systems with misalignment is >6%, and only 1% have planets in retrograde orbits. We also obtain a positive correlation between the survival planet number and the distance from the cluster center r: planetary systems with a larger r tend to be more stable. Moreover, stars with a mass >2.5 M{sub Sun} are likely unstable and lose their planets. These results are roughly consistent with current observations. Planetary systems in binaries are less stable and we achieve a rough criterion: most of the binary systems with a{sub b}(1-e{sub b}{sup 2})>100 AU can retain all the initial planets. Finally, 80% of the FFPs are ejected out of the clusters, while the rest ({approx}20%) still stay in host clusters and most of them are concentrated in the center (<2 pc)

  8. The microlensing rate and distribution of free-floating planets towards the Galactic bulge

    NASA Astrophysics Data System (ADS)

    Ban, M.; Kerins, E.; Robin, A. C.

    2016-10-01

    Context. Ground-based optical microlensing surveys have provided tantalising, if inconclusive, evidence for a significant population of free-floating planets (FFPs). Both ground- and space-based facilities are being used and developed which will be able to probe the distrubution of FFPs with much better sensitivity. It is also vital to develop a high-precision microlensing simulation framework to evaluate the completeness of such surveys. Aims: We present the first signal-to-noise limited calculations of the FFP microlensing rate using the Besançon Galactic model. The microlensing distribution towards the Galactic centre is simulated for wide-area ground-based optical surveys (I-band) such as OGLE or MOA, a wide-area ground-based near-infrared survey (K-band), and a targeted space-based near-infrared survey (H-band) which could be undertaken with Euclid or WFIRST. Methods: We present a calculation framework for the computation of the optical and near-infrared microlensing rate and optical depth for simulated stellar catalogues which are signal-to-noise limited, and take account of extinction, unresolved stellar background light, and finite source size effects, which can be significant for FFPs. Results: We find that the global ground-based I-band yield over a central 200 deg2 region covering the Galactic centre ranges from 20 Earth-mass FFPs yr-1 up to 3500 yr-1 for Jupiter FFPs in the limit of 100% detection efficiency, and almost an order of magnitude larger for a K-band survey. For ground-based surveys we find that the inclusion of finite source and the unresolved background reveals a mass-dependent variation in the spatial distribution of FFPs. For a targeted space-based H-band covering 2 deg2, the yield depends on the target field but maximises close to the Galactic centre with around 76 Earth to 1700 Jupiter FFPs per year. For near-IR space-based surveys like Euclid or WFIRST the spatial distribution of FFPs is found to be largely insensitive to the FFP mass

  9. ON THE ORIGIN OF PLANETS AT VERY WIDE ORBITS FROM THE RECAPTURE OF FREE FLOATING PLANETS

    SciTech Connect

    Perets, Hagai B.; Kouwenhoven, M. B. N. E-mail: thijskouwenhoven@gmail.com

    2012-05-01

    In recent years, several planets have been discovered at wide orbits (>100 AU) around their host stars. Theoretical studies encounter difficulties in explaining their formation and origin. Here we propose a novel scenario for the production of planetary systems at such orbits, through the dynamical recapture of free floating planets (FFPs) in dispersing stellar clusters and stellar associations. This process is a natural extension of the recently suggested scenario for the formation of wide stellar binaries. We use N-body simulations of dispersing clusters with 10-1000 stars and comparable numbers of FFPs to study this process. We find that planets are captured into wide orbits in the typical range {approx}few Multiplication-Sign 100-10{sup 6} AU and have a wide range of eccentricities (thermal distribution). Typically, 3-6 Multiplication-Sign (f{sub FFP}/1)% of all stars capture a planetary companion with such properties (where f{sub FFP} is the number of FFP per star in the birth clusters). The planetary capture efficiency is comparable to that of capture-formed stellar binaries, and shows a similar dependence on the cluster size and structure. It is almost independent of the specific planetary mass; planets as well as substellar companions of any mass can be captured. The capture efficiency decreases with increasing cluster size, and for a given cluster size it increases with the host/primary mass. We also find that more than one planet can be captured around the same host through independent consecutive captures; similarly, planets can be captured into binary systems, both in circumstellar and circumbinary orbits. We also expect planets to be captured into pre-existing planetary (and protoplanetary systems) as well as into orbits around black holes and massive white dwarfs, if these formed early enough before the cluster dispersal. In particular, stellar black holes have a high capture efficiency (>50% and 5-10 Multiplication-Sign (f{sub FFP}/1)% for capture of

  10. On the Origin of Planets at Very Wide Orbits from the Recapture of Free Floating Planets

    NASA Astrophysics Data System (ADS)

    Perets, Hagai B.; Kouwenhoven, M. B. N.

    2012-05-01

    In recent years, several planets have been discovered at wide orbits (>100 AU) around their host stars. Theoretical studies encounter difficulties in explaining their formation and origin. Here we propose a novel scenario for the production of planetary systems at such orbits, through the dynamical recapture of free floating planets (FFPs) in dispersing stellar clusters and stellar associations. This process is a natural extension of the recently suggested scenario for the formation of wide stellar binaries. We use N-body simulations of dispersing clusters with 10-1000 stars and comparable numbers of FFPs to study this process. We find that planets are captured into wide orbits in the typical range ~few × 100-106 AU and have a wide range of eccentricities (thermal distribution). Typically, 3-6 × (f FFP/1)% of all stars capture a planetary companion with such properties (where f FFP is the number of FFP per star in the birth clusters). The planetary capture efficiency is comparable to that of capture-formed stellar binaries, and shows a similar dependence on the cluster size and structure. It is almost independent of the specific planetary mass; planets as well as substellar companions of any mass can be captured. The capture efficiency decreases with increasing cluster size, and for a given cluster size it increases with the host/primary mass. We also find that more than one planet can be captured around the same host through independent consecutive captures; similarly, planets can be captured into binary systems, both in circumstellar and circumbinary orbits. We also expect planets to be captured into pre-existing planetary (and protoplanetary systems) as well as into orbits around black holes and massive white dwarfs, if these formed early enough before the cluster dispersal. In particular, stellar black holes have a high capture efficiency (>50% and 5-10 × (f FFP/1)% for capture of stars and planetary companions, respectively) due to their large mass. Finally

  11. Momentum transfer to a free floating double slit: realization of a thought experiment from the Einstein-Bohr debates.

    PubMed

    Schmidt, L Ph H; Lower, J; Jahnke, T; Schößler, S; Schöffler, M S; Menssen, A; Lévêque, C; Sisourat, N; Taïeb, R; Schmidt-Böcking, H; Dörner, R

    2013-09-01

    We simultaneously measured the momentum transferred to a free-floating molecular double slit and the momentum change of the atom scattering from it. Our experimental results are compared to quantum mechanical and semiclassical models. The results reveal that a classical description of the slits, which was used by Einstein in his debate with Bohr, provides a surprisingly good description of the experimental results, even for a microscopic system, if momentum transfer is not ascribed to a specific pathway but shared coherently and simultaneously between both.

  12. Thresholds in the response of free-floating plant abundance to variation in hydraulic connectivity, nutrients, and macrophyte abundance in a large floodplain river

    USGS Publications Warehouse

    Giblin, Shawn M.; Houser, Jeffrey N.; Sullivan, John F.; Langrehr, H.A.; Rogala, James T.; Campbell, Benjamin D.

    2014-01-01

    Duckweed and other free-floating plants (FFP) can form dense surface mats that affect ecosystem condition and processes, and can impair public use of aquatic resources. FFP obtain their nutrients from the water column, and the formation of dense FFP mats can be a consequence and indicator of river eutrophication. We conducted two complementary surveys of diverse aquatic areas of the Upper Mississippi River as an in situ approach for estimating thresholds in the response of FFP abundance to nutrient concentration and physical conditions in a large, floodplain river. Local regression analysis was used to estimate thresholds in the relations between FFP abundance and phosphorus (P) concentration (0.167 mg l−1L), nitrogen (N) concentration (0.808 mg l−1), water velocity (0.095 m s−1), and aquatic macrophyte abundance (65 % cover). FFP tissue concentrations suggested P limitation was more likely in spring, N limitation was more likely in late summer, and N limitation was most likely in backwaters with minimal hydraulic connection to the channel. The thresholds estimated here, along with observed patterns in nutrient limitation, provide river scientists and managers with criteria to consider when attempting to modify FFP abundance in off-channel areas of large river systems.

  13. Search for free-floating planetary-mass objects in the Pleiades

    NASA Astrophysics Data System (ADS)

    Zapatero Osorio, M. R.; Gálvez Ortiz, M. C.; Bihain, G.; Bailer-Jones, C. A. L.; Rebolo, R.; Henning, Th.; Boudreault, S.; Béjar, V. J. S.; Goldman, B.; Mundt, R.; Caballero, J. A.

    2014-08-01

    Aims: We aim at identifying the least massive population of the solar metallicity, young (120 Myr), nearby (133.5 pc) Pleiades star cluster with the ultimate goal of understanding the physical properties of intermediate-age, free-floating, low-mass brown dwarfs and giant planetary-mass objects, and deriving the cluster substellar mass function across the deuterium-burning mass limit at ≈0.012 M⊙. Methods: We performed a deep photometric and astrometric J- and H-band survey covering an area of ~0.8 deg2 in the Pleiades cluster. The images with completeness and limiting magnitudes of J,H ≈ 20.2 and ≈21.5 mag were acquired ~9 yr apart, allowing us to derive proper motions with a typical precision of ±6 mas yr-1. For the cluster distance and age, the survey is sensitive to Pleiades members with masses in the interval ≈0.2-0.008 M⊙. J- and H-band data were complemented with Z, K, and mid-infrared magnitudes up to 4.6 μm coming from the UKIRT Infrared Deep Sky Survey (UKIDSS), the WISE catalog, and follow-up observations of our own. Pleiades member candidates were selected to have proper motions compatible with that of the cluster, and colors following the known Pleiades sequence in the interval J = 15.5-18.8 mag, and ZUKIDSS - J ≥ 2.3 mag or Z nondetections for J> 18.8 mag. Results: We found a neat sequence of astrometric and photometric Pleiades substellar member candidates with two or more proper motion measurements and with magnitudes and masses in the intervals J = 15.5-21.2 mag and ≈0.072-0.008 M⊙. The faintest objects show very red near- and mid-infrared colors exceeding those of field high-gravity dwarfs by ≥0.5 mag. This agrees with the reported properties of field young L-type dwarfs and giant planets orbiting stars of ages of ~100 Myr. The Pleiades photometric sequence does not show any color turn-over because of the presence of photospheric methane absorption down to J = 20.3 mag, which is about 1 mag fainter than predicted by the

  14. Free-floating thrombus of the carotid artery with a homozygous methylenetetrahydrofolate reductase gene mutation: a case report.

    PubMed

    Colak, Necmettin; Nazli, Yunus; Kosehan, Dilek; Alpay, Mehmet Fatih; Cakir, Omer

    2013-02-01

    Free-floating thrombus (FFT) of the carotid artery is a rare condition of currently unknown etiology. We describe a symptomatic patient with an FFT in the left common carotid artery. A duplex ultrasonography scan showed the presence of a mobile floating thrombus moving in cyclical motion with the cardiac cycles in the left common carotid artery. During emergency surgery, an FFT was seen at this location and removed. No underlying wall defect was seen at the time of surgery. In a genetic screening test, TT homozygous for the methylenetetrahydrofolate reductase (MTHFR) C677T genetic polymorphisms was detected. The patient recovered uneventfully, with no neurogical events. Lifelong anticoagulant therapy was recommended. An aggressive surgical approach is recommended in the patient to prevent embolic episodes. PMID:22101856

  15. An Atypically Large, Free-Floating Thrombus Extending From the Lung to the Left Atrium via a Pulmonary Vein

    PubMed Central

    Wang, Wei; Li, Xuechang; Song, Weian; Zhang, Yunshan; Yue, Caiying; Shang, Liqun; Li, Jun; Wen, Feng; Liu, Junqiang; Zha, Peng

    2015-01-01

    Abstract An atypically large, free-floating thrombus extending from primary pulmonary malignancy into the left atrium (LA) is a rare phenomenon. Here, we report a 61-year-old man presenting with a large mass in the lower lobe of the left lung, extending to LA via the left inferior pulmonary vein. The thrombus remained clinically silent and was detected by computed tomography (CT) and transthoracic echocardiography. To prevent life-threatening complications including systemic embolism and sudden death, the patient underwent surgical excision of the mass under cardiopulmonary bypass. Pathology of the tumor and the embolus was confirmed as moderately differentiated squamous cell carcinoma. Furthermore, immunohistochemical studies demonstrated consistency of the tumor cells in this pathological category. The patient tolerated the surgery well and his condition began to improve gradually after the operation. PMID:26579798

  16. Response diversity of free-floating plants to nutrient stoichiometry and temperature: growth and resting body formation.

    PubMed

    McCann, Michael J

    2016-01-01

    Free-floating plants, like most groups of aquatic primary producers, can become nuisance vegetation under certain conditions. On the other hand, there is substantial optimism for the applied uses of free-floating plants, such as wastewater treatment, biofuel production, and aquaculture. Therefore, understanding the species-specific responses of floating plants to abiotic conditions will inform both management decisions and the beneficial applications of these plants. I measured the responses of three floating plant species common in the northeast United States (Lemna minor, Spirodela polyrhiza, and Wolffia brasiliensis) to nutrient stoichiometry (nitrogen and phosphorus) and temperature in the laboratory. I also used survey data to determine the pattern of species richness of floating plants in the field and its relationship with the dominance of this group. Floating plant species exhibited unique responses to nutrient stoichiometry and temperature in the laboratory, especially under low temperatures (18 °C) and low nutrient conditions (0.5 mg N L(-1), 0.083 mg P L(-1)). The three species displayed an apparent tradeoff with different strategies of growth or dormancy. In the field, water bodies with three or more species of floating plants were not more frequently dominated by this group. The response diversity observed in the lab may not be associated with the dominance of this group in the field because it is masked by environmental variability, has a weak effect, or is only important during transient circumstances. Future research to develop applied uses of floating plants should examine response diversity across a greater range of species or clones and environmental conditions.

  17. Response diversity of free-floating plants to nutrient stoichiometry and temperature: growth and resting body formation.

    PubMed

    McCann, Michael J

    2016-01-01

    Free-floating plants, like most groups of aquatic primary producers, can become nuisance vegetation under certain conditions. On the other hand, there is substantial optimism for the applied uses of free-floating plants, such as wastewater treatment, biofuel production, and aquaculture. Therefore, understanding the species-specific responses of floating plants to abiotic conditions will inform both management decisions and the beneficial applications of these plants. I measured the responses of three floating plant species common in the northeast United States (Lemna minor, Spirodela polyrhiza, and Wolffia brasiliensis) to nutrient stoichiometry (nitrogen and phosphorus) and temperature in the laboratory. I also used survey data to determine the pattern of species richness of floating plants in the field and its relationship with the dominance of this group. Floating plant species exhibited unique responses to nutrient stoichiometry and temperature in the laboratory, especially under low temperatures (18 °C) and low nutrient conditions (0.5 mg N L(-1), 0.083 mg P L(-1)). The three species displayed an apparent tradeoff with different strategies of growth or dormancy. In the field, water bodies with three or more species of floating plants were not more frequently dominated by this group. The response diversity observed in the lab may not be associated with the dominance of this group in the field because it is masked by environmental variability, has a weak effect, or is only important during transient circumstances. Future research to develop applied uses of floating plants should examine response diversity across a greater range of species or clones and environmental conditions. PMID:26989619

  18. Response diversity of free-floating plants to nutrient stoichiometry and temperature: growth and resting body formation

    PubMed Central

    2016-01-01

    Free-floating plants, like most groups of aquatic primary producers, can become nuisance vegetation under certain conditions. On the other hand, there is substantial optimism for the applied uses of free-floating plants, such as wastewater treatment, biofuel production, and aquaculture. Therefore, understanding the species-specific responses of floating plants to abiotic conditions will inform both management decisions and the beneficial applications of these plants. I measured the responses of three floating plant species common in the northeast United States (Lemna minor, Spirodela polyrhiza, and Wolffia brasiliensis) to nutrient stoichiometry (nitrogen and phosphorus) and temperature in the laboratory. I also used survey data to determine the pattern of species richness of floating plants in the field and its relationship with the dominance of this group. Floating plant species exhibited unique responses to nutrient stoichiometry and temperature in the laboratory, especially under low temperatures (18 °C) and low nutrient conditions (0.5 mg N L−1, 0.083 mg P L−1). The three species displayed an apparent tradeoff with different strategies of growth or dormancy. In the field, water bodies with three or more species of floating plants were not more frequently dominated by this group. The response diversity observed in the lab may not be associated with the dominance of this group in the field because it is masked by environmental variability, has a weak effect, or is only important during transient circumstances. Future research to develop applied uses of floating plants should examine response diversity across a greater range of species or clones and environmental conditions. PMID:26989619

  19. Toward More Free-Floating Model Cell Membranes: Method Development and Application to Their Interaction with Nanoparticles.

    PubMed

    Yousefi, Nariman; Wargenau, Andreas; Tufenkji, Nathalie

    2016-06-15

    Identifying the mechanisms of nanoparticle (NP) interactions with cell membranes is key to understanding potential NP cytotoxicity and applications as nanocarriers for targeted drug delivery. To elucidate these mechanisms of interaction, supported phospholipid bilayers (SPBs) are commonly used as models of cell membranes. However, SPBs are soft thin films, and, as such, their properties can be significantly affected by the underlying substrate. Free-floating cell membranes would be best modeled by weakly adhered SPBs; thus, we propose a method for tailoring the interfacial interaction of an electrically charged SPB-substrate system based on modulations in the solution chemistry. Using the dissipation signal of the quartz crystal microbalance with dissipation monitoring (QCM-D), we show that the method can be used to tailor SPB-substrate interactions without the loss of its structural integrity. To demonstrate the application of the method, SPBs are exposed to cationic and anionic polystyrene latex NPs. These studies reveal that the bilayer response to the modulations in the interfacial interaction with its underlying substrate can be used as a sensitive tool to probe the integrity of SPBs upon exposure to NPs. As expected, anionic NPs tend to impart no significant damage to the anionic bilayers, whereas cationic NPs can be detrimental to bilayer integrity. This is the first report of a QCM-D based method to probe bilayer integrity following exposure to NPs. Importantly, the degree of SPB interaction with its underlying substrate is shown to be a critical factor in the kinetics of bilayer disruption by cationic NPs, whereby weakly adhered bilayers are prone to significantly faster breakup. Since free-floating cell membranes are better represented by a weakly adhered SPB, the results of this work critically influence paradigms in experimental studies involving SPBs as models for cell membranes.

  20. Toward More Free-Floating Model Cell Membranes: Method Development and Application to Their Interaction with Nanoparticles.

    PubMed

    Yousefi, Nariman; Wargenau, Andreas; Tufenkji, Nathalie

    2016-06-15

    Identifying the mechanisms of nanoparticle (NP) interactions with cell membranes is key to understanding potential NP cytotoxicity and applications as nanocarriers for targeted drug delivery. To elucidate these mechanisms of interaction, supported phospholipid bilayers (SPBs) are commonly used as models of cell membranes. However, SPBs are soft thin films, and, as such, their properties can be significantly affected by the underlying substrate. Free-floating cell membranes would be best modeled by weakly adhered SPBs; thus, we propose a method for tailoring the interfacial interaction of an electrically charged SPB-substrate system based on modulations in the solution chemistry. Using the dissipation signal of the quartz crystal microbalance with dissipation monitoring (QCM-D), we show that the method can be used to tailor SPB-substrate interactions without the loss of its structural integrity. To demonstrate the application of the method, SPBs are exposed to cationic and anionic polystyrene latex NPs. These studies reveal that the bilayer response to the modulations in the interfacial interaction with its underlying substrate can be used as a sensitive tool to probe the integrity of SPBs upon exposure to NPs. As expected, anionic NPs tend to impart no significant damage to the anionic bilayers, whereas cationic NPs can be detrimental to bilayer integrity. This is the first report of a QCM-D based method to probe bilayer integrity following exposure to NPs. Importantly, the degree of SPB interaction with its underlying substrate is shown to be a critical factor in the kinetics of bilayer disruption by cationic NPs, whereby weakly adhered bilayers are prone to significantly faster breakup. Since free-floating cell membranes are better represented by a weakly adhered SPB, the results of this work critically influence paradigms in experimental studies involving SPBs as models for cell membranes. PMID:27211513

  1. Dynamics modeling and control of a 6-DOF space robot with flexible panels for capturing a free floating target

    NASA Astrophysics Data System (ADS)

    Yu, Zhang-wei; Liu, Xiao-feng; Cai, Guo-ping

    2016-11-01

    In many kinds of on-orbit space robot tasks, capturing free floating target using space robot attracts more attention of researchers. However, most existing researches about dynamics and control of space robot concern planar problem, and the effect of flexible panel on capturing dynamics of the system is not considered. In this paper, spatial dynamics and control of a 6-DOF space robot with flexible panels are investigated and spatial impact problem is considered. Dynamic model of the system is established by the single direction recursive construction method and the Jourdain's velocity variation principle. The Hertz contact and impact theory and the method of computer graphics are used to establish the impact model. The computed torque control method is used to design active controller to suppress the spacecraft drift caused by the impact. Numerical simulation results show that the established dynamic model is effective in describing the dynamics behavior of the space robot; flexible panels have big influence on impact dynamic characteristics; the designed controller may effectively control the spacecraft drift during the capture process.

  2. WISEA J114724.10-204021.3: A Free-floating Planetary Mass Member of the TW Hya Association

    NASA Astrophysics Data System (ADS)

    Schneider, Adam C.; Windsor, James; Cushing, Michael C.; Kirkpatrick, J. Davy; Wright, Edward L.

    2016-05-01

    We present WISEA J114724.10-204021.3, a young, low-mass, high-probability member of the TW Hya association (TWA). WISEA J114724.10-204021.3 was discovered based on its red AllWISE color (W1 ‑ W2 = 0.63 mag) and extremely red 2MASS J ‑ K S color (>2.64 mag), the latter of which is confirmed with near-infrared photometry from the Visible and Infrared Survey Telescope for Astronomy Hemisphere Survey (J ‑ K S = 2.57 ± 0.03). Follow-up near-infrared spectroscopy shows a spectral type of L7 ± 1 as well as several spectroscopic indicators of youth. These include a peaked H-band shape and a steeper K-band slope, traits typically attributed to low surface gravity. The sky position, proper motion, and distance estimates of WISEA J114724.10-204021.3 are all consistent with membership in the ˜10 Myr old TWA. Using the age of the TWA and evolutionary models, we estimate the mass of WISEA J114724.10-204021.3 to be 5–13 M Jup, making it one of the youngest and lowest-mass free-floating objects yet discovered in the Solar neighborhood.

  3. MICROLENS TERRESTRIAL PARALLAX MASS MEASUREMENTS: A RARE PROBE OF ISOLATED BROWN DWARFS AND FREE-FLOATING PLANETS

    SciTech Connect

    Gould, Andrew; Yee, Jennifer C. E-mail: jyee@astronomy.ohio-state.edu

    2013-02-10

    Terrestrial microlens parallax is one of the very few methods that can measure the mass and number density of isolated dark low-mass objects, such as old free-floating planets and brown dwarfs. Terrestrial microlens parallax can be measured whenever a microlensing event differs substantially as observed from two or more well-separated sites. If the lens also transits the source during the event, then its mass can be measured. We derive an analytic expression for the expected rate of such events and then use this to derive two important conclusions. First, the rate is directly proportional to the number density of a given population, greatly favoring low-mass populations relative to their contribution to the general microlensing rate, which further scales as M {sup 1/2} where M is the lens mass. Second, the rate rises sharply as one probes smaller source stars, despite the fact that the probability of transit falls directly with source size. We propose modifications to current observing strategies that could yield a factor of 100 increase in sensitivity to these rare events.

  4. Combustion studies of coal-derived solid fuels. Part IV. Correlation of ignition temperatures from thermogravimetry and free-floating experiments

    USGS Publications Warehouse

    Rostam-Abadi, M.; DeBarr, J.A.; Chen, W.T.

    1992-01-01

    The usefulness of TG as an efficient and practical method to characterize the combustion properties of fuels used in large-scale combustors is of considerable interest. Relative ignition temperatures of a lignite, an anthracite, a bituminous coal and three chars derived from this coal were measured by a free-floating technique. These temperatures were correlated with those estimated from TG burning profiles of the fuels. ?? 1992.

  5. Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column

    PubMed Central

    Peeters, Edwin T. H. M.; Neefjes, Rozemarijn E. M.; van Zuidam, Bastiaan G.

    2016-01-01

    Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natans)and the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously experienced phosphorus

  6. Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column.

    PubMed

    Peeters, Edwin T H M; Neefjes, Rozemarijn E M; Zuidam, Bastiaan G van

    2016-01-01

    Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natans)and the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously experienced phosphorus

  7. On the Feasibility of Characterizing Free-floating Planets with Current and Future Space-based Microlensing Surveys

    NASA Astrophysics Data System (ADS)

    Henderson, Calen B.; Shvartzvald, Yossi

    2016-10-01

    Simultaneous space- and ground-based microlensing surveys, such as K2's Campaign 9 (K2C9) and WFIRST, facilitate measuring the masses and distances of free-floating planet (FFP) candidates, which are identified as single-lens events with timescales that are of the order of 1 day. Measuring the mass and distance of an FFP lens requires determining the size of the source star ρ, measuring the microlens parallax {π }{{E}}, and using high-resolution imaging to search for the lens flux {F}{\\ell } from a possible host star. Here we investigate the accessible parameter space for each of these components considering different satellites for a range of FFP masses, Galactic distances, and source star properties. We find that at the beginning of K2C9, when its projected separation {D}\\perp from the Earth is ≲0.2 au, it will be able to measure {π }{{E}} for Jupiter-mass FFP candidates at distances larger than ∼2 kpc and to Earth-mass lenses at ∼8 kpc. At the end of K2C9, when {D}\\perp = 0.81 au, it is sensitive to planetary-mass lenses for distances ≳3.5 kpc, and even then only to those with mass ≳M Jup. From lens flux constraints we find that it will be possible to exclude hosts down to the deuterium-burning limit for events within ∼2 kpc. This indicates that the ability to characterize FFPs detected during K2C9 is optimized for events occurring toward the beginning of the campaign. WFIRST, on the other hand, will be able to detect and characterize FFP masses down to or below super-Earths throughout the Galaxy during its entire microlensing survey.

  8. Serotonin axons of the neostriatum show a higher affinity for striatal than for ventral mesencephalic transplants: a quantitative study in adult and immature recipient rats.

    PubMed

    Pierret, P; Vallée, A; Bosler, O; Dorais, M; Moukhles, H; Abbaszadeh, R; Lepage, Y; Doucet, G

    1998-07-01

    We previously showed that grafts of fetal ventral mesencephalic tissue are practically not innervated by host serotonin (5-HT) axons after implantation into the striatum of rats aged more than 14 days, at variance with transplants of cortical or striatal tissue into the adult striatum, which are well innervated by these axons. Using 5-HT immunohistochemistry and in vitro [3H]5-HT uptake/autoradiography, we have examined and quantified the innervation of ventral mesencephalic versus striatal grafts several months after implantation into the striatum of neonatal (postnatal day 5 or P5), juvenile (P15), and adult rats. Ventral mesencephalic grafts implanted in P5 rats received a moderate 5-HT innervation, while similar grafts implanted in P15 or adult recipients were almost free of any 5-HT fibers (-80%, compared to P5). The density of 5-HT innervation showed a tendency toward higher values in striatal than in ventral mesencephalic grafts (1.6-2 times higher in P5 and adult recipients; 4 times higher in P15 recipients). The difference was more striking, and significant, when only the true striatal portions of the striatal grafts were considered, i.e., DARPP-32-immunopositive areas (4-5 times higher in P5 and adult recipients; 10 times higher in P15 recipients). Accordingly, these DARPP-32-positive areas were also more densely innervated than the DARPP-32-negative zones of the same grafts (3 times higher at any age). The 5-HT innervation density also decreased with increasing age of the recipients in DARPP-32-positive, as well as DARPP-32-negative compartments of the striatal grafts (-75% in adults), but this decrease appeared more gradual (-50% in juveniles) than with mesencephalic grafts. It is concluded that the 5-HT axons innervating the neostriatum have a better affinity for striatal grafts than for ventral mesencephalic grafts or the nonstriatal portions of striatal grafts. In adulthood, the relative affinity of these axons for the different types of grafts is

  9. Immunohistochemistry on freely floating fixed tissue sections.

    PubMed

    Bachman, Julia

    2013-01-01

    Immunohistochemistry on free floating tissue sections is done for many reasons, all of which involve labeling tissue to visualize a certain cell type, protein, or structural component. Visualization is aided by mounting sections on microscope slides for stabilization, and is in most cases necessary for the appropriate use of objectives with a high numerical aperture and high degree of magnification.

  10. SEARCH FOR VERY LOW-MASS BROWN DWARFS AND FREE-FLOATING PLANETARY-MASS OBJECTS IN TAURUS

    SciTech Connect

    Quanz, Sascha P.; Goldman, Bertrand; Henning, Thomas; Brandner, Wolfgang; Burrows, Adam; Hofstetter, Lorne W.

    2010-01-01

    The number of low-mass brown dwarfs and even free floating planetary-mass objects in young nearby star-forming (SF) regions and associations is continuously increasing, offering the possibility to study the low-mass end of the initial mass function in greater detail. In this paper, we present six new candidates for (very) low-mass objects in the Taurus SF region one of which was recently discovered in parallel by Luhman et al. The underlying data we use is part of a new database from a deep near-infrared survey at the Calar Alto observatory. The survey is more than 4 mag deeper than the Two Micron All Sky Survey and covers currently approx1.5 deg{sup 2}. Complementary optical photometry from Sloan Digital Sky Survey were available for roughly 1.0 deg{sup 2}. After selection of the candidates using different color indices, additional photometry from Spitzer/IRAC was included in the analysis. In greater detail, we focus on two very faint objects for which we obtained J-band spectra. Based on comparison with reference spectra, we derive a spectral type of L2 +- 0.5 for one object, making it the object with the latest spectral type in Taurus known today. From models, we find the effective temperature to be 2080 +- 140 K and the mass 5-15 Jupiter masses. For the second source, the J-band spectrum does not provide definite proof of the young, low-mass nature of the object, as the expected steep water vapor absorption at 1.33 mum is not present in the data. We discuss the probability that this object might be a background giant or carbon star. If it were a young Taurus member, however, a comparison to theoretical models suggests that it lies close to or even below the deuterium burning limit (<13 M{sub Jup}) as well. A first proper motion analysis for both objects shows that they are good candidates for being Taurus members.

  11. Embryonic cerebrospinal fluid collaborates with the isthmic organizer to regulate mesencephalic gene expression.

    PubMed

    Parada, Carolina; Martín, Cristina; Alonso, María I; Moro, José A; Bueno, David; Gato, Angel

    2005-11-01

    Early in development, the behavior of neuroepithelial cells is controlled by several factors acting in a developmentally regulated manner. Recently it has been shown that diffusible factors contained within embryonic cerebrospinal fluid (CSF) promote neuroepithelial cell survival, proliferation, and neurogenesis in mesencephalic explants lacking any known organizing center. In this paper, we show that mesencephalic and mesencephalic+isthmic organizer explants cultured only with basal medium do not express the typically expressed mesencephalic or isthmic organizer genes analyzed (otx2 and fgf8, respectively) and that mesencephalic explants cultured with embryonic CSF-supplemented medium do effect such expression, although they exhibit an altered pattern of gene expression, including ectopic shh expression domains. Other trophic sources that are able to maintain normal neuroepithelial cell behavior, i.e., fibroblast growth factor-2, fail to activate this ectopic shh expression. Conversely, the expression pattern of the analyzed genes in mesencephalic+isthmic organizer explants cultured with embryonic cerebrospinal fluid-supplemented medium mimics the pattern for control embryos developed in ovo. We demonstrate that embryonic CSF collaborates with the isthmic organizer in regulation of the expression pattern of some characteristic neuroectodermal genes during early stages of central nervous system (CNS) development, and we suggest that this collaboration is not restricted to the maintenance of neuroepithelial cell survival. Data reported in this paper corroborate the hypothesis that factors contained within embryonic CSF contribute to the patterning of the CNS during early embryonic development. PMID:16180222

  12. Mesencephalic representations of recent experience influence decision making

    PubMed Central

    Thompson, John A; Costabile, Jamie D; Felsen, Gidon

    2016-01-01

    Decisions are influenced by recent experience, but the neural basis for this phenomenon is not well understood. Here, we address this question in the context of action selection. We focused on activity in the pedunculopontine tegmental nucleus (PPTg), a mesencephalic region that provides input to several nuclei in the action selection network, in well-trained mice selecting actions based on sensory cues and recent trial history. We found that, at the time of action selection, the activity of many PPTg neurons reflected the action on the previous trial and its outcome, and the strength of this activity predicted the upcoming choice. Further, inactivating the PPTg predictably decreased the influence of recent experience on action selection. These findings suggest that PPTg input to downstream motor regions, where it can be integrated with other relevant information, provides a simple mechanism for incorporating recent experience into the computations underlying action selection. DOI: http://dx.doi.org/10.7554/eLife.16572.001 PMID:27454033

  13. Human primitive meninges in and around the mesencephalic flexure and particularly their topographical relation to cranial nerves.

    PubMed

    Cho, Kwang Ho; Rodríguez-Vázquez, Jose Francisco; Han, Eui Hyeog; Verdugo-López, Samuel; Murakami, Gen; Cho, Baik Hwan

    2010-09-20

    Development of the meninges in and around the plica ventralis encephali has not been well documented. A distinct mesenchymal structure, the so-called plica ventralis encephali, is sandwiched by the fetal mesencephalic flexure. We histologically examined paraffin-embedded sections from 18 human embryos and fetuses at 6-12 weeks of gestation. In the loose tissues of the plica, the first meninx appeared as a narrow membrane along the oculomotor nerve at 7-8 weeks. Subsequently, the plica ventralis evolved into 3 parts: bilateral lateral mesenchymal condensations and a primitive membranous meninx extending between. Notably, the topographical anatomy of the oculomotor, trochlear and trigeminal nerves did not change: the oculomotor nerve ran along the rostral aspect of the membranous meninx, the trigeminal nerve ran along the caudal side of the lateral mesenchymal condensation, and the trochlear nerve remained embedded in the lateral condensation. Up to 9-10 weeks, the lateral mesenchymal condensations became tongue-like folds; i.e., the primitive form of the tentorium cerebelli, while the membranous meninx became the diaphragma sellae. The falx cerebri seemed to develop from the tongue-like folds. Overall, the final tentorium cerebelli corresponded to the regressed plica ventralis, while the parasellar area originated from the base of the plica and other tissues along the ventral aspects of the basisphenoid and basioccipital.

  14. SHORT-DURATION LENSING EVENTS. I. WIDE-ORBIT PLANETS? FREE-FLOATING LOW-MASS OBJECTS? OR HIGH-VELOCITY STARS?

    SciTech Connect

    Di Stefano, Rosanne

    2012-08-01

    Short-duration lensing events tend to be generated by low-mass lenses or by lenses with high transverse velocities. Furthermore, for any given lens mass and speed, events of short duration are preferentially caused by nearby lenses (mesolenses) that can be studied in detail, or else by lenses so close to the source star that finite-source-size effects may be detected, yielding information about both the Einstein ring radius and the surface of the lensed star. Planets causing short-duration events may be in orbits with any orientation, and may have semimajor axes smaller than 1 AU, or they may reach the outer limits of their planetary systems, in the region corresponding to the solar system's Oort Cloud. They can have masses larger than Jupiter's or smaller than Pluto's. Lensing therefore has a unique potential to expand our understanding of planetary systems. A particular advantage of lensing is that it can provide precision measurements of system parameters, including the masses of and projected separation between star and planet. We demonstrate how the parameters can be extracted and show that a great deal can be learned. For example, it is remarkable that the gravitational mass of nearby free-floating planet-mass lenses can be measured by complementing observations of a photometric event with deep images that detect the planet itself. A fraction of short events may be caused by high-velocity stars located within a kiloparsec. Many high-velocity lenses are likely to be neutron stars that received large natal kicks. Other high-speed stars may be members of the halo population. Still others may be hypervelocity stars that have been ejected from the Galactic center, or runaway stars escaped from close binaries, possibly including the progenitor binaries of Type Ia supernovae.

  15. Long-range pollution transport during the MILAGRO-2006 campaign: a case study of a major Mexico City outflow event using free-floating altitude-controlled balloons

    SciTech Connect

    Voss, Paul B.; Zaveri, Rahul A.; Flocke, Frank M.; Mao, Huitimg; Hartley, Tom; DeAmicis, Pam; Deonandan, Indira; Contrerars-Jimenez, G.; Martinez-Antonio, O.; Figueroa Estrada, M.; Greenberg, David; Campos, Teresa; Weinheimer, Andrew J.; Knapp, David; Montzka, DeeDee; Crounse, J. D.; Wennberg, P. O.; Apel, Eric; Madronich, Sasha; de Foy, B.

    2010-08-04

    One of the major objectives of the Megacities Initiative: Local And Global Research 3 Observations (MILAGRO 2006) campaign was to investigate the long-range transport of 4 Mexico City Metropolitan Area (MCMA) pollution outflow and its downwind impacts on air 5 quality and climate. Four aircraft (DOE G-1, NSF/NCAR C-130, NASA-J31, and NASA 6 DC-8) made extensive chemical, aerosol, and radiation measurements above MCMA and over 7 1000 km downwind in order to characterize the evolution of MCMA pollution as it aged and 8 dispersed over the central Mexican plateau and the Gulf of Mexico. As part of this effort, 9 free-floating Controlled-Meteorological (CMET) balloons, capable of changing altitude on 10 command via satellite, characterized the MCMA outflow by performing repeated soundings 11 during the transit. In this paper, we present an analysis based on the data from two CMET 12 balloons that were launched near Mexico City on the afternoon of 18 March 2006 and floated 13 downwind with the outflow for nearly 30 hours. Continuous profile measurements made by 14 the balloons show the evolving structure of the MCMA outflow in considerable detail: its 15 stability and stratification, interaction with other air masses, mixing episodes, and dispersion 16 into the regional background. Air parcel trajectories, computed directly from the balloon 17 wind profiles, show three different transport pathways for Mexico City outflow on 18-19 18 March: (a) high-altitude advection of the top of the MCMA mixed layer, (b) low-altitude flow 19 over the Sierra Madre Oriental followed by decoupling and isolated transport over the Gulf, 20 and (c) the same decoupling scenario with entrainment into a cleaner westerly jet below the 21 plateau. The C-130 intercepted the balloon-based trajectories three times on 19 March, once 22 along each transport pathway. In all three cases, distinct peaks in the urban tracer signature 23 and LIDAR backscatter imagery provided evidence for Mexico City air

  16. Characterization and antimicrobial resistance of Salmonella isolated from internal tissues, ceca and rinse samples from commercial broiler chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence, serotype, and antimicrobial resistance profile of Salmonella from internal tissues (spleen, liver/gall bladder, thymus, Meckel’s diverticulum, and free floating yolk), ceca and carcass rinse samples were determined from six-week-old (n=30) and eight-week-old (n=40) commercial broilers ...

  17. The effect of different durations of morphine exposure on mesencephalic dopaminergic neurons in morphine dependent rats.

    PubMed

    Shi, Weibo; Ma, Chunling; Qi, Qian; Liu, Lizhe; Bi, Haitao; Cong, Bin; Li, Yingmin

    2015-12-01

    Mesencephalic dopaminergic neurons are heavily involved in the development of drug dependence. Thyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine synthesis, plays an important role in the survival of dopaminergic neurons. Therefore, this study investigated TH changes in dopaminergic neurons of the ventral tegmental area (VTA) and substantia nigra (SN), as well as the morphine effects on dopaminergic neurons induced by different durations of morphine dependence. Models of morphine dependence were established in rats, and paraffin-embedded sections, immunohistochemistry and western blotting were used to observe the changes in the expression of TH protein. Fluoro-Jade B staining was used to detect degeneration and necrosis, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) detected the apoptosis of mesencephalic dopaminergic nerve cells. Immunohistochemistry and western blotting showed that the number of TH positive cells and the protein levels in the VTA and SN were significantly decreased in the rats with a long period of morphine dependency. With prolonged morphine exposure, the dopaminergic nerve cells in the VTA and SN showed degeneration and necrosis, while apoptotic cells were not observed. The number of VTA and SN dopaminergic nerve cells decreased with increasing periods of morphine dependence, which was most likely attributable to the degeneration and necrosis of nerve cells induced by morphine toxicity.

  18. Free-floating left atrial ball thrombus after mitral valve replacement with patent coronary artery bypass grafts: successful removal by a right minithoracotomy approach without aortic cross-clamp.

    PubMed

    Hisatomi, Kazuki; Hashizume, Koji; Tanigawa, Kazuyoshi; Miura, Takashi; Matsukuma, Seiji; Yokose, Shogo; Kitamura, Tessho; Shimada, Takashi; Eishi, Kiyoyuki

    2016-06-01

    A free-floating thrombus in the left atrium without attachment to either the atrial wall or the mitral valve is extremely rare. We describe a case in a 79-year-old woman with chronic atrial fibrillation and a recent stroke who had undergone mitral valve replacement 25 years previously and coronary artery bypass grafting 5 years previously. Redo cardiac surgery represents a clinical challenge due to a higher rate of peri-operative morbidity and mortality. Median re-sternotomy can be particularly difficult in patients with functioning coronary artery grafts, where the risk of graft injury is a significant concern. Prompt surgical intervention was carried out, and to avoid the challenge of re-sternotomy in this patient with two prior thoracotomies, we successfully removed the thrombus by a right minithoracotomy approach without aortic cross-clamping. There was no postoperative occurrence of a new stroke or aggravation of the pre-existing stroke.

  19. The Extremely Red, Young L Dwarf PSO J318.5338-22.8603: A Free-floating Planetary-mass Analog to Directly Imaged Young Gas-giant Planets

    NASA Astrophysics Data System (ADS)

    Liu, Michael C.; Magnier, Eugene A.; Deacon, Niall R.; Allers, Katelyn N.; Dupuy, Trent J.; Kotson, Michael C.; Aller, Kimberly M.; Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Hodapp, K. W.; Jedicke, R.; Kaiser, N.; Kudritzki, R.-P.; Metcalfe, N.; Morgan, J. S.; Price, P. A.; Tonry, J. L.; Wainscoat, R. J.

    2013-11-01

    We have discovered using Pan-STARRS1 an extremely red late-L dwarf, which has (J - K)MKO = 2.78 and (J - K)2MASS = 2.84, making it the reddest known field dwarf and second only to 2MASS J1207-39b among substellar companions. Near-IR spectroscopy shows a spectral type of L7 ± 1 and reveals a triangular H-band continuum and weak alkali (K I and Na I) lines, hallmarks of low surface gravity. Near-IR astrometry from the Hawaii Infrared Parallax Program gives a distance of 24.6 ± 1.4 pc and indicates a much fainter J-band absolute magnitude than field L dwarfs. The position and kinematics of PSO J318.5-22 point to membership in the β Pic moving group. Evolutionary models give a temperature of 1160^{+30}_{-40} K and a mass of 6.5^{+1.3}_{-1.0} M Jup, making PSO J318.5-22 one of the lowest mass free-floating objects in the solar neighborhood. This object adds to the growing list of low-gravity field L dwarfs and is the first to be strongly deficient in methane relative to its estimated temperature. Comparing their spectra suggests that young L dwarfs with similar ages and temperatures can have different spectral signatures of youth. For the two objects with well constrained ages (PSO J318.5-22 and 2MASS J0355+11), we find their temperatures are ≈400 K cooler than field objects of similar spectral type but their luminosities are similar, i.e., these young L dwarfs are very red and unusually cool but not "underluminous." Altogether, PSO J318.5-22 is the first free-floating object with the colors, magnitudes, spectrum, luminosity, and mass that overlap the young dusty planets around HR 8799 and 2MASS J1207-39.

  20. The lifelong maintenance of mesencephalic dopaminergic neurons by Nurr1 and engrailed

    PubMed Central

    2014-01-01

    Specific vulnerability and degeneration of the dopaminergic neurons in the substantia nigra pars compacta of the midbrain is the pathological hallmark of Parkinson’s disease. A number of transcription factors regulate the birth and development of this set of neurons and some remain constitutively expressed throughout life. These maintenance transcription factors are closely associated with essential neurophysiological functions and are required ultimately for the long-term survival of the midbrain dopaminergic neurons. The current review describes the role of two such factors, Nurr1 and engrailed, in differentiation, maturation, and in normal physiological functions including acquisition of neurotransmitter identity. The review will also elucidate the relationship of these factors with life, vulnerability, degeneration and death of mesencephalic dopaminergic neurons in the context of Parkinson’s disease. PMID:24685177

  1. Basal and stress-induced corticosterone secretion is decreased by lesion of mesencephalic dopaminergic neurons.

    PubMed

    Casolini, P; Kabbaj, M; Leprat, F; Piazza, P V; Rougé-Pont, F; Angelucci, L; Simon, H; Le Moal, M; Maccari, S

    1993-09-17

    There is evidence that certain psychopathological conditions are accompanied by a dysfunction in both the hypothalamo-pituitary-adrenal axis and dopaminergic systems, although the relationship between these two systems is as yet unclear. In the present study we investigated the effect of a specific lesion of dopamine mesencephalic neurons (Ventral Tegmental Area) on basal and stress-induced corticosterone secretion. Three weeks after injection of 6-OHDA, there was a depletion in dopamine in the frontal cortex and in the ventral and dorsal striatum, whereas norepinephrine and serotonin levels were unchanged. The dopamine-lesioned rats exhibited a lower basal and stress-induced corticosterone secretion than the sham-lesioned animals. The results indicate that the dopaminergic system may have a stimulatory influence on the hypothalamo-pituitary-adrenal axis. PMID:8242373

  2. Astasia, asymmetrical asterixis and pretectal syndrome in thalamo-mesencephalic hemorrhage.

    PubMed

    de Pablo-Fernández, Eduardo; Villarejo, Alberto; Domínguez-González, Cristina; Hidalgo, Fernando Sierra; Callero, Elisa Correas

    2009-11-01

    We report a patient who presented with sudden onset instability and diplopia. On neurological examination he had asymmetrical asterixis, predominantly in the left hand, and ocular findings consistent with a pretectal syndrome. He was also unable to stand or even sit up unassisted, with a tendency to tilt his body and rotate his trunk axis to the left. Brain MRI showed a hemorrhage in the right thalamo-mesencephalic junction. This region involves important structures for the control of postural stability, motor control, ocular movements and vestibulo-ocular integration, not yet well understood. To our knowledge, this is the first reported case with the simultaneous combination of astasia, prectectal syndrome and asymmetrical asterixis.

  3. Glucocorticoids have state-dependent stimulant effects on the mesencephalic dopaminergic transmission.

    PubMed

    Piazza, P V; Rougé-Pont, F; Deroche, V; Maccari, S; Simon, H; Le Moal, M

    1996-08-01

    An increase in the activity of mesencephalic dopaminergic neurons has been implicated in the appearance of pathological behaviors such as psychosis and drug abuse. Several observations suggest that glucocorticoids might contribute to such an increase in dopaminergic activity. The present experiments therefore analyzed the effects of corticosterone, the major glucocorticoid in the rat, both on dopamine release in the nucleus accumbens of freely moving animals by means of microdialysis, and on locomotor activity, a behavior dependent on accumbens dopamine. Given that glucocorticoids have certain state-dependent neuronal effects, their action on dopamine was studied in situations differing in dopaminergic tonus, including during the light and dark phases of the circadian cycle, during eating, and in groups of animals differing in their locomotor reactivity to novelty. Dopaminergic activity is increased in the dark period, further increased during food-intake, and is higher in rats defined as high responders to novelty than in low responders. Corticosterone, peripherally administered in a dose that approximates stress-induced plasma concentrations, increased extracellular concentrations of dopamine, and this increase was augmented in the dark phase, during eating, and in high responder rats. Corticosterone had little or no effects in the light phase and in low responder rats. Corticosterone also stimulated locomotor activity, an effect that paralleled the release of dopamine and was abolished by neurochemical (6-hydroxydopamine) depletion of accumbens dopamine. In conclusion, glucocorticoids have state-dependent stimulant effects on mesencephalic dopaminergic transmission, and an interaction between these two factors might be involved in the appearance of behavioral disturbances. PMID:8710937

  4. Glucocorticoids have state-dependent stimulant effects on the mesencephalic dopaminergic transmission.

    PubMed Central

    Piazza, P V; Rougé-Pont, F; Deroche, V; Maccari, S; Simon, H; Le Moal, M

    1996-01-01

    An increase in the activity of mesencephalic dopaminergic neurons has been implicated in the appearance of pathological behaviors such as psychosis and drug abuse. Several observations suggest that glucocorticoids might contribute to such an increase in dopaminergic activity. The present experiments therefore analyzed the effects of corticosterone, the major glucocorticoid in the rat, both on dopamine release in the nucleus accumbens of freely moving animals by means of microdialysis, and on locomotor activity, a behavior dependent on accumbens dopamine. Given that glucocorticoids have certain state-dependent neuronal effects, their action on dopamine was studied in situations differing in dopaminergic tonus, including during the light and dark phases of the circadian cycle, during eating, and in groups of animals differing in their locomotor reactivity to novelty. Dopaminergic activity is increased in the dark period, further increased during food-intake, and is higher in rats defined as high responders to novelty than in low responders. Corticosterone, peripherally administered in a dose that approximates stress-induced plasma concentrations, increased extracellular concentrations of dopamine, and this increase was augmented in the dark phase, during eating, and in high responder rats. Corticosterone had little or no effects in the light phase and in low responder rats. Corticosterone also stimulated locomotor activity, an effect that paralleled the release of dopamine and was abolished by neurochemical (6-hydroxydopamine) depletion of accumbens dopamine. In conclusion, glucocorticoids have state-dependent stimulant effects on mesencephalic dopaminergic transmission, and an interaction between these two factors might be involved in the appearance of behavioral disturbances. PMID:8710937

  5. THE EXTREMELY RED, YOUNG L DWARF PSO J318.5338–22.8603: A FREE-FLOATING PLANETARY-MASS ANALOG TO DIRECTLY IMAGED YOUNG GAS-GIANT PLANETS

    SciTech Connect

    Liu, Michael C.; Magnier, Eugene A.; Kotson, Michael C.; Aller, Kimberly M.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Jedicke, R.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Tonry, J. L.; Wainscoat, R. J.; Deacon, Niall R.; Allers, Katelyn N.; Dupuy, Trent J.; Draper, P. W.; Price, P. A.; Metcalfe, N.

    2013-11-10

    We have discovered using Pan-STARRS1 an extremely red late-L dwarf, which has (J – K){sub MKO} = 2.78 and (J – K){sub 2MASS} = 2.84, making it the reddest known field dwarf and second only to 2MASS J1207–39b among substellar companions. Near-IR spectroscopy shows a spectral type of L7 ± 1 and reveals a triangular H-band continuum and weak alkali (K I and Na I) lines, hallmarks of low surface gravity. Near-IR astrometry from the Hawaii Infrared Parallax Program gives a distance of 24.6 ± 1.4 pc and indicates a much fainter J-band absolute magnitude than field L dwarfs. The position and kinematics of PSO J318.5–22 point to membership in the β Pic moving group. Evolutionary models give a temperature of 1160{sup +30}{sub -40} K and a mass of 6.5{sup +1.3}{sub -1.0} M {sub Jup}, making PSO J318.5–22 one of the lowest mass free-floating objects in the solar neighborhood. This object adds to the growing list of low-gravity field L dwarfs and is the first to be strongly deficient in methane relative to its estimated temperature. Comparing their spectra suggests that young L dwarfs with similar ages and temperatures can have different spectral signatures of youth. For the two objects with well constrained ages (PSO J318.5–22 and 2MASS J0355+11), we find their temperatures are ≈400 K cooler than field objects of similar spectral type but their luminosities are similar, i.e., these young L dwarfs are very red and unusually cool but not 'underluminous'. Altogether, PSO J318.5–22 is the first free-floating object with the colors, magnitudes, spectrum, luminosity, and mass that overlap the young dusty planets around HR 8799 and 2MASS J1207–39.

  6. Neurotoxicity of cerebro-spinal fluid from patients with Parkinson's disease on mesencephalic primary cultures as an in vitro model of dopaminergic neurons.

    PubMed

    Kong, Ping; Zhang, Ben-Shu; Lei, Ping; Kong, Xiao-Dong; Zhang, Shi-Shuang; Li, Dai; Zhang, Yun

    2015-08-01

    Parkinson's disease is a degenerative disorder of the central nervous system. In spite of extensive research, neither the cause nor the mechanisms have been firmly established thus far. One assumption is that certain toxic substances may exist in the cerebro-spinal fluid (CSF) of Parkinson's disease patients. To confirm the neurotoxicity of CSF and study the potential correlation between neurotoxicity and the severity of Parkinson's disease, CSF was added to cultured cells. By observation of cell morphology, changes in the levels of lactate dehydrogenase, the ratio of tyrosine hydroxylase-positive cells, and the expression of tyrosine hydroxylase mRNA and protein, the differences between the two groups were shown. The created in vitro model of dopaminergic neurons using primary culture of mouse embryonic mesencephalic tissue is suitable for the study of neurotoxicity. The observations of the present study indicated that CSF from Parkinson's disease patients contains factors that can cause specific injury to cultured dopaminergic neurons. However, no obvious correlation was found between the neurotoxicity of CSF and the severity of Parkinson's disease.

  7. Generation and properties of a new human ventral mesencephalic neural stem cell line

    SciTech Connect

    Villa, Ana; Liste, Isabel; Courtois, Elise T.; Seiz, Emma G.; Ramos, Milagros; Meyer, Morten; Juliusson, Bengt; Kusk, Philip

    2009-07-01

    Neural stem cells (NSCs) are powerful research tools for the design and discovery of new approaches to cell therapy in neurodegenerative diseases like Parkinson's disease. Several epigenetic and genetic strategies have been tested for long-term maintenance and expansion of these cells in vitro. Here we report the generation of a new stable cell line of human neural stem cells derived from ventral mesencephalon (hVM1) based on v-myc immortalization. The cells expressed neural stem cell and radial glia markers like nestin, vimentin and 3CB2 under proliferation conditions. After withdrawal of growth factors, proliferation and expression of v-myc were dramatically reduced and the cells differentiated into astrocytes, oligodendrocytes and neurons. hVM1 cells yield a large number of dopaminergic neurons (about 12% of total cells are TH{sup +}) after differentiation, which also produce dopamine. In addition to proneural genes (NGN2, MASH1), differentiated cells show expression of several genuine mesencephalic dopaminergic markers such as: LMX1A, LMX1B, GIRK2, ADH2, NURR1, PITX3, VMAT2 and DAT, indicating that they retain their regional identity. Our data indicate that this cell line and its clonal derivatives may constitute good candidates for the study of development and physiology of human dopaminergic neurons in vitro, and to develop tools for Parkinson's disease cell replacement preclinical research and drug testing.

  8. Neuroprotection of resveratrol against neurotoxicity induced by methamphetamine in mouse mesencephalic dopaminergic neurons.

    PubMed

    Sun, Dong; Yue, Qingwei; Guo, Weihua; Li, Tao; Zhang, Jing; Li, Guibao; Liu, Zengxun; Sun, Jinhao

    2015-01-01

    Resveratrol is originally extracted from huzhang, a Chinese herbal medicine. Recently, resveratrol has attracted a great of attention due to its antioxidant and antiapoptotic properties. Although the neuroprotection of resveratrol on neural damages in various models has been well characterized, little is known about the role of resveratrol in methamphetamine (MA) induced neurotoxicity in mesencephalic dopaminergic neurons. Dopaminergic neurons were isolated from midbrain of mouse embryos at embryonic day 15 and cultured in the presence of MA and resveratrol. Cell viability was examined by MTT assay and the apoptosis was assessed using Hoechst33342/PI double staining. To evaluate the Oxidative damage, ROS assay was performed. Moreover, the changes of time course of intracellular free calcium concentration ([Ca(2+) ]i) were analyzed with Fluo-3/AM tracing. The data showed that MA induced the neurotoxicity of cultured cells in a dose-dependent manner. Resveratrol significantly increased cellular viability and retarded cell apoptosis. Furthermore, resveratrol also attenuated MA induced ROS production and intracellular free calcium overload. Our results suggest that resveratrol protects dopaminergic neurons from MA-induced neuronal cytotoxicity, which, at least partly, is mediated by inhibition of [Ca(2+) ]i and oxidative stress. © 2015 BioFactors 41(4):252-260, 2015.

  9. Differential sensitivity of immature and mature ventral mesencephalic neurons to rotenone induced neurotoxicity in vitro.

    PubMed

    Satish Bollimpelli, V; Kondapi, Anand K

    2015-12-25

    Rotenone induced neuronal toxicity in ventral mesencephalic (VM) dopaminergic (DA) neurons in culture is widely accepted as an important model for the investigation of Parkinson's disease (PD). However, little is known about developmental stage dependent toxic effects of rotenone on VM neurons in vitro. The objective of present study is to investigate the effect of rotenone on developing VM neurons at immature versus mature stages. Primary VM neurons were cultured in the absence of glial cells. Exposure of VM neurons to rotenone for 2 days induced cell death in both immature and mature neurons in a concentration-dependent manner, but to a greater extent in mature neurons. While rotenone-treated mature VM neurons showed α-synuclein aggregation and sensitivity to DA neurons, immature VM neurons exhibited only DA neuronal sensitivity but not α-synuclein aggregation. In addition, on rotenone treatment, enhancement of caspase-3 activity and reactive oxygen species (ROS) production were higher in mature VM neurons than in immature neurons. These results suggest that even though both mature and immature VM neurons are sensitive to rotenone, their manifestations differ from each other, with only mature VM neurons exhibiting Parkinsonian conditions.

  10. Direct projection from the lateral habenula to the trigeminal mesencephalic nucleus in rats.

    PubMed

    Ohara, Haruka; Tachibana, Yoshihisa; Fujio, Takashi; Takeda-Ikeda, Rieko; Sato, Fumihiko; Oka, Ayaka; Kato, Takafumi; Ikenoue, Etsuko; Yamashiro, Takashi; Yoshida, Atsushi

    2016-01-01

    Trigeminal mesencephalic nucleus (Vmes) neurons are primary afferents conveying deep sensation from the masticatory muscle spindles or the periodontal mechanoreceptors, and are crucial for controlling jaw movements. Their cell bodies exist in the brain and receive descending commands from a variety of cortical and subcortical structures involved in limbic (emotional) systems. However, it remains unclear how the lateral habenula (LHb), a center of negative emotions (e.g., pain, stress and anxiety), can influence the control of jaw movements. To address this issue, we examined whether and how the LHb directly projects to the Vmes by means of neuronal tract tracing techniques in rats. After injections of a retrograde tracer Fluorogold in the rostral and caudal Vmes, a number of neurons were labeled in the lateral division of LHb (LHbl) bilaterally, whereas a few neurons were labeled in the medial division of LHb (LHbm) bilaterally. After injections of an anterograde tracer, biotinylated dextranamine (BDA) in the LHbl, a small number of labeled axons were distributed bilaterally in the rostral and caudal levels of Vmes, where some labeled axonal boutons contacted the cell body of rostral and caudal levels of Vmes neurons bilaterally. After the BDA injection into the LHbm, however, no axons were labeled bilaterally in the rostral and caudal levels of Vmes. Therefore, the present study for the first time demonstrated the direct projection from the LHbl to the Vmes and the detailed projection patterns, suggesting that jaw movements are modulated by negative emotions that are signaled by LHbl neurons. PMID:26592775

  11. The red nucleus and mesencephalic tegmentum in a ranid amphibian: a cytoarchitectonic and HRP connectional study.

    PubMed

    Larson-Prior, L J; Cruce, W L

    1992-01-01

    Movement control in vertebrates is a complex function that is known to involve several parallel systems. In amphibians, which lack the isocortical structures shown in mammals to initiate and control voluntary movements, supraspinal motor control systems have received surprisingly little attention. Because amphibians lack a corticospinal equivalent, coordination and control of all movement strategies must take place in non-cortical, supraspinal integrating centers. The rubro-cerebello-rubrospinal circuit is likely to represent a major motor control system in such vertebrates. In this anatomical investigation four mesencephalic tegmentospinal projection nuclei are described in ranid amphibians (Rana catesbiana and Rana pipiens): reticular formation, accessory optic complex, interstitial nucleus of Cajal, and the red nucleus. The red nucleus, which shows no distinct somatotopic organization, can be distinguished because it is the only one of the four that is predominantly contralateral in its projections. Horseradish peroxidase injections into the tegmentum and the cerebellum demonstrated that the red nucleus also maintains reciprocal connections with the cerebellum via the deep cerebellar nucleus. These connections could not be localized to any distinct region in the deep cerebellar nuclear mass, suggesting that this represents a single cerebellar recipient nucleus. Thus, anuran amphibians are shown to possess the major pathways that comprise the rubro-cerebello-rubrospinal circuitry in mammals. PMID:1472987

  12. Effects of chronic lesions in mesencephalic raphe nuclei on induction of pseudopregnancy.

    PubMed

    Maekawa, F; Yamanouchi, K

    1996-08-01

    The role of mesencephalic raphe nuclei in the induction of pseudopregnancy was investigated in female rats. The dorsal or median raphe nucleus lesions (DRL or MRL, respectively) were made by means of a radiofrequency lesion generator. Two or 3 weeks after the operation, in order to induce pseudopregnancy, the vagina was stimulated electrically on the day of proestrus or 1 mg/kg b.w. reserpine was injected on the day of diestrus I. Traumatization by passing thread to one uterine horn was performed to induce deciduoma 5 days after vaginal stimulation or 3 days after reserpine injection. As the results, decidual response was seen in most control and sham females in both vaginal stimulation and reserpine-treated groups. In contrast, incidences of deciduoma in DRL females with vaginal stimulation or reserpine-injection were significantly lower than those in control and sham groups. In the MRL females with either vaginal stimulation or reserpine-treatment, incidences of deciduoma were comparable to those of the control and sham operated groups. These results suggest that the dorsal raphe nucleus plays an important role in pseudopregnancy-inducing mechanisms in female rats.

  13. Increased circulating concentrations of mesencephalic astrocyte-derived neurotrophic factor in children with type 1 diabetes

    PubMed Central

    Galli, Emilia; Härkönen, Taina; Sainio, Markus T.; Ustav, Mart; Toots, Urve; Urtti, Arto; Yliperttula, Marjo; Lindahl, Maria; Knip, Mikael; Saarma, Mart; Lindholm, Päivi

    2016-01-01

    Mesencephalic astrocyte-derived neurotrophic factor (MANF) was recently shown to be essential for the survival and proliferation of pancreatic β-cells in mice, where deletion of MANF resulted in diabetes. The current study aimed at determining whether the concentration of circulating MANF is associated with the clinical manifestation of human type 1 diabetes (T1D). MANF expression in T1D or MANF levels in serum have not been previously studied. We developed an enzyme-linked immunosorbent assay (ELISA) for MANF and measured serum MANF concentrations from 186 newly diagnosed children and adolescents and 20 adults with longer-term T1D alongside with age-matched controls. In healthy controls the mean serum MANF concentration was 7.0 ng/ml. High MANF concentrations were found in children 1–9 years of age close to the diagnosis of T1D. The increased MANF concentrations were not associated with diabetes-predictive autoantibodies and autoantibodies against MANF were extremely rare. Patients with conspicuously high MANF serum concentrations had lower C-peptide levels compared to patients with moderate MANF concentrations. Our data indicate that increased MANF concentrations in serum are associated with the clinical manifestation of T1D in children, but the exact mechanism behind the increase remains elusive. PMID:27356471

  14. Cholinergic mesencephalic neurons are involved in gait and postural disorders in Parkinson disease

    PubMed Central

    Karachi, Carine; Grabli, David; Bernard, Frédéric A.; Tandé, Dominique; Wattiez, Nicolas; Belaid, Hayat; Bardinet, Eric; Prigent, Annick; Nothacker, Hans-Peter; Hunot, Stéphane; Hartmann, Andreas; Lehéricy, Stéphane; Hirsch, Etienne C.; François, Chantal

    2010-01-01

    Gait disorders and postural instability, which are commonly observed in elderly patients with Parkinson disease (PD), respond poorly to dopaminergic agents used to treat other parkinsonian symptoms. The brain structures underlying gait disorders and falls in PD and aging remain to be characterized. Using functional MRI in healthy human subjects, we have shown here that activity of the mesencephalic locomotor region (MLR), which is composed of the pedunculopontine nucleus (PPN) and the adjacent cuneiform nucleus, was modulated by the speed of imagined gait, with faster imagined gait activating a discrete cluster within the MLR. Furthermore, the presence of gait disorders in patients with PD and in aged monkeys rendered parkinsonian by MPTP intoxication correlated with loss of PPN cholinergic neurons. Bilateral lesioning of the cholinergic part of the PPN induced gait and postural deficits in nondopaminergic lesioned monkeys. Our data therefore reveal that the cholinergic neurons of the PPN play a central role in controlling gait and posture and represent a possible target for pharmacological treatment of gait disorders in PD. PMID:20628197

  15. An involvement of trigeminal mesencephalic neurons in regulation of occlusal vertical dimension in the guinea pig.

    PubMed

    Zhang, W; Kobayashi, M; Moritani, M; Masuda, Y; Dong, J; Yagi, T; Maeda, T; Morimoto, T

    2003-07-01

    Although the occlusal vertical dimension (OVD) is strictly controlled, the neuronal mechanism of its regulation is still unclear. We hypothesize that neurons in the trigeminal mesencephalic nucleus (MesV) play an important role in the regulation of the OVD, because the MesV receives the projection from jaw-closing muscle spindles and periodontal mechanoreceptors. We measured the temporal OVD change in the guinea pig to study the effects of MesV lesions on the OVD. OVD-raised animals without MesV lesions showed a rapid OVD decrease to the same level as that in naïve controls, followed by an OVD increase after the OVD-raising appliance was removed. In contrast, OVD-raised animals with MesV lesions showed only a slight decrease in the OVD for 15 days after removal of the appliance, and then the OVD increased. The time-course of OVD development in normal-bite animals with MesV lesions was similar to that of naïve controls. These results suggest that MesV neurons are involved in OVD regulation. PMID:12821720

  16. Curcumin Protects against 1-Methyl-4-phenylpyridinium Ion- and Lipopolysaccharide-Induced Cytotoxicities in the Mouse Mesencephalic Astrocyte via Inhibiting the Cytochrome P450 2E1

    PubMed Central

    Gui, Hai-Yan; Chen, Rui-Ni; Peng, Yan; Hu, Jin-Hua; Mao, Zhao; Ning, Rui; Shang, Wei; Liu, Wei; Xiong, Jing; Hu, Gang; Yang, Jian

    2013-01-01

    Curcumin is extracted from the rhizomes of the ginger family plant Curcuma longa L., which has a good protection for liver, kidney, and immune system. However, there is little information about its contribution in protection of astrocytes recently. The present study was undertaken to elucidate the protective effect of curcumin, an herbal antioxidant, on 1-methyl-4-phenylpyridinium ion- (MPP+-) and lipopolysaccharide- (LPS-) induced cytotoxicities, as well as the underlying mechanisms by using primary mouse mesencephalic astrocytes. The results showed that curcumin protected the mesencephalic astrocytes from MPP+- and LPS-induced toxicities along with reducing reactive oxygen species (P < 0.05) and maleic dialdehyde (P < 0.05) sufficiently. Moreover, curcumin significantly inhibited the cytochrome P450 2E1 (CYP2E1) expression (P < 0.01 at mRNA level, P < 0.05 at protein level) and its activity (P < 0.05) sufficiently induced by MPP+ and LPS in the mouse mesencephalic astrocytes. And curcumin as well as diallyl sulphide, a CYP2E1 positive inhibitor, ameliorated MPP+- and LPS-induced mouse mesencephalic astrocytes damage. Accordingly, curcumin protects against MPP+- and LPS-induced cytotoxicities in the mouse mesencephalic astrocyte via inhibiting the CYP2E1 expression and activity. PMID:23843878

  17. Estrogen protects against dopamine neuron toxicity in primary mesencephalic cultures through an indirect P13K/Akt mediated astrocyte pathway.

    PubMed

    Bains, Mona; Roberts, James L

    2016-01-01

    Astrocytes regulate neuronal homeostasis and have been implicated in affecting the viability and functioning of surrounding neurons under stressed and injured conditions. Previous data from our lab suggests indirect actions of estrogen through ERα in neighboring astroglia to protect dopamine neurons against 1-methyl-4-phenylpyridinium (MPP(+)) toxicity in mouse mesencephalic cultures. We further evaluate estrogen signaling in astrocytes and the mechanism of estrogen's indirect neuroprotective effects on dopamine neurons. Primary mesencephalic cultures pre-treated with 17β-estradiol and the membrane impermeable estrogen, E2-BSA, were both neuroprotective against MPP(+) -induced dopamine neuron toxicity, suggesting membrane-initiated neuroprotection. ERα was found in the plasma membrane of astrocyte cultures and colocalized with the lipid raft marker, flotillin-1. A 17β-estradiol time course revealed a significant increase in Akt, which was inhibited by the PI3 kinase inhibitor, LY294004. Estrogen conditioned media collected from pure astrocyte cultures rescued glial deficient mesencephalic cultures from MPP(+). This indirect estrogen-mediated neuroprotective effect in mesencephalic cultures was significantly reduced when PI3 kinase signaling in astrocytes was blocked prior to collecting estrogen-conditioned media using the irreversible PI3 kinase inhibitor, Wortmannin. Estrogen signaling via astrocytes is rapidly initiated at the membrane level and requires PI3 kinase signaling in order to protect primary mesencephalic dopamine neurons from MPP(+) neurotoxicity. PMID:26520464

  18. Interleukin-10 Protection against Lipopolysaccharide-Induced Neuro-Inflammation and Neurotoxicity in Ventral Mesencephalic Cultures

    PubMed Central

    Zhu, Yan; Chen, Xiao; Liu, Zhan; Peng, Yu-Ping; Qiu, Yi-Hua

    2015-01-01

    Interleukin (IL)-10, an anti-inflammatory cytokine, is expressed in the brain and can inhibit microglial activation. Herein, we utilized lipopolysaccharide (LPS)-induced inflammatory Parkinson’s disease (PD) cell model to determine whether microglia and astrocytes are necessary targets for IL-10 neuroprotection. Primary ventral mesencephalic (VM) cultures with different composition of neurons, microglia and astrocytes were prepared. The cells were exposed to IL-10 (15, 50 or 150 ng/mL) 1 h prior to LPS (50 ng/mL) treatment. LPS induced dopaminergic and non-dopaminergic neuronal loss in VM cultures, VM neuron-enriched cultures, and neuron-microglia co-cultures, but not in neuron-astrocyte co-cultures. IL-10 reduced LPS-induced neuronal loss particularly in single VM neuron cultures. Pro-inflammatory mediators (TNF-α, IL-1β, inducible nitric oxide synthase and cyclooxygenase-2) were upregulated in both neuron-microglia and neuron-astrocyte co-cultures by LPS. In contrast, neurotrophic factors (brain-derived neurotrophic factor, insulin-like growth factor-1 or glial cell-derived neurotrophic factor) were downregulated in neuron-microglia co-cultures, but upregulated in neuron-astrocyte co-cultures by LPS. IL-10 reduced both the increase in production of the pro-inflammatory mediators and the decrease in production of the neurotrophic factors induced by LPS. These results suggest that astrocytes can balance LPS neurotoxicity by releasing more neurotrophic factors and that IL-10 exerts neuroprotective property by an extensive action including direct on neurons and indirect via inhibiting microglial activation. PMID:26729090

  19. Exaggerated sympathetic and cardiovascular responses to stimulation of the mesencephalic locomotor region in spontaneously hypertensive rats.

    PubMed

    Liang, Nan; Mitchell, Jere H; Smith, Scott A; Mizuno, Masaki

    2016-01-01

    The sympathetic and pressor responses to exercise are exaggerated in hypertension. However, the underlying mechanisms causing this abnormality remain to be fully elucidated. Central command, a neural drive originating in higher brain centers, is known to activate cardiovascular and locomotor control circuits concomitantly. As such, it is a viable candidate for the generation of the augmented vascular response to exercise in this disease. We hypothesized that augmentations in central command function contribute to the heightened cardiovascular response to exercise in hypertension. To test this hypothesis, changes in renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) in response to electrical stimulation of mesencephalic locomotor region (MLR; 20-50 μA in 10-μA steps evoking fictive locomotion), a putative component of the central command pathway, were examined in decerebrate, paralyzed normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Tibial nerve discharge during MLR stimulation significantly increased in an intensity-dependent manner in both WKY and SHR but was not different between groups. Stimulation of the MLR evoked significantly larger increases in RSNA and MAP with increasing stimulation intensity in both groups. Importantly, the increases in sympathetic and pressor responses to this fictive locomotion were significantly greater in SHR compared with WKY across all stimulation intensities (e.g., at 50 μA, ΔRSNA: WKY 153 ± 31%, SHR 287 ± 42%; ΔMAP: WKY 87 ± 9 mmHg, SHR 139 ± 7 mmHg). These findings provide the first evidence that central command may be a critical contributor to the exaggerated rise in sympathetic activity and blood pressure during exercise in hypertension. PMID:26545711

  20. Induction of rhythmic jaw movements by stimulation of the mesencephalic reticular formation in the guinea pig.

    PubMed

    Hashimoto, N; Katayama, T; Ishiwata, Y; Nakamura, Y

    1989-08-01

    This study was designed to investigate whether stimulation of the mesencephalic reticular formation (MRF) induces rhythmic jaw movements (RJMs) and, if it does so, to determine the RJM-inducing region in the MRF in ketamine-anesthetized guinea pigs. The results were as follows: (1) Repetitive electrical stimulation of the MRF at the level of the red nucleus induced rhythmic EMG bursts in the anterior digastric muscle (DIG). (2) The duration and cycle time of the rhythmic DIG EMG burst induced from the medial MRF were longer than those induced from the lateral MRF. (3) Repetitive MRF stimulation after paralysis still induced rhythmic multiple-unit activities in the anterior digastric motoneuron pool. (4) Neither precollicular decerebration nor cerebellectomy affected the MRF induction of RJMs. (5) Transverse hemisection at the rostral border of the pons abolished the RJMs induced from the contralateral, but not ipsilateral, MRF. Midline section of the midbrain abolished RJMs induced from the MRF on either side. (6) A lesion in the pontine pyramidal tract abolished the RJMs induced by stimulation of the ipsilateral cortical masticatory area (CMA), but not those induced from the contralateral MRF. (7) A unilateral lesion of the oral portion of the gigantocellular reticular nucleus, where the rhythm generator for the CMA-induced RJMs is located, abolished RJMs induced from not only the CMA, but also MRF on the contralateral side. (8) Microinjection of L-glutamate into the lateral, but not medial, MRF induced RJMs similar to those elicited by repetitive electrical stimulation of the same site.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. The mesencephalic locomotor region sends a bilateral glutamatergic drive to hindbrain reticulospinal neurons in a tetrapod

    PubMed Central

    Ryczko, Dimitri; Auclair, Francois; Cabelguen, Jean‐Marie

    2015-01-01

    In vertebrates, stimulation of the mesencephalic locomotor region (MLR) on one side evokes symmetrical locomotor movements on both sides. How this occurs was previously examined in detail in a swimmer using body undulations (lamprey), but in tetrapods the downstream projections from the MLR to brainstem neurons are not fully understood. Here we examined the brainstem circuits from the MLR to identified reticulospinal neurons in the salamander Notophthalmus viridescens. Using neural tracing, we show that the MLR sends bilateral projections to the middle reticular nucleus (mRN, rostral hindbrain) and the inferior reticular nucleus (iRN, caudal hindbrain). Ca2+ imaging coupled to electrophysiology in in vitro isolated brains revealed very similar responses in reticulospinal neurons on both sides to a unilateral MLR stimulation. As the strength of MLR stimulation was increased, the responses increased in size in reticulospinal neurons of the mRN and iRN, but the responses in the iRN were smaller. Bath‐application or local microinjections of glutamatergic antagonists markedly reduced reticulospinal neuron responses, indicating that the MLR sends glutamatergic inputs to reticulospinal neurons. In addition, reticulospinal cells responded to glutamate microinjections and the size of the responses paralleled the amount of glutamate microinjected. Immunofluorescence coupled with anatomical tracing confirmed the presence of glutamatergic projections from the MLR to reticulospinal neurons. Overall, we show that the brainstem circuits activated by the MLR in the salamander are organized similarly to those previously described in lampreys, indicating that the anatomo‐physiological features of the locomotor drive are well conserved in vertebrates. J. Comp. Neurol. 524:1361–1383, 2016. © 2015 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:26470600

  2. Diencephalic and mesencephalic efferents of the medial prefrontal cortex in the rat: electrophysiological evidence for the existence of branched axons.

    PubMed

    Thierry, A M; Chevalier, G; Ferron, A; Glowinski, J

    1983-01-01

    Efferents originating from the rat medial prefrontal cortex and projecting to diencephalic and mesencephalic structures were analyzed electrophysiologically. The antidromic activation technique was used in order to identify cortical neurons which innervate the medio-dorsal nucleus of the thalamus (MD), lateral habenula, ventro-medial mesencephalic tegmentum (VMT), substantia nigra (SN), superior colliculus (SC) and central gray (CG). Corresponding cortical neurons, found mainly in layers V and VI, were distributed in the rostro-caudal extension of the medial prefrontal cortex. Their conduction velocities were relatively slow and ranged between 0.4 and 5.5 m/s. The reciprocal collision test allowed us to determine whether a given cortical neuron innervated only one structure or whether it sent axon collaterals to other subcortical areas. Twelve patterns of axonal branching were established: MD-VMT, MD-SN, MD-SC, VMT-SN, VMT-SC, VMT-CG, SN-SC, habenula-VMT, habenula-CG, MD-SN-SC, VMT-SN-SC and VMT-habenula-CG. Finally, it was estimated that a large proportion of the prefrontal cells which project to a given subcortical structure also innervate one or two other subcortical areas. Results are discussed in the light of anatomical data and their functional significance.

  3. Upbeat-torsional nystagmus and contralateral fourth nerve palsy due to unilateral dorsal ponto-mesencephalic lesion

    PubMed Central

    Thurtell, Matthew J.; Tomsak, Robert L.; Leigh, R. John

    2010-01-01

    The central projections of the anterior semicircular canals are thought to be conveyed from the vestibular nuclei to the ocular motor nuclei in the midbrain by three distinct brainstem pathways: the medial longitudinal fasciculus, crossing ventral tegmental tract, and brachium conjunctivum. There is controversy as to whether upbeat nystagmus could result from lesions involving each of these pathways. We report a 52-year-old man who presented with a contralesional fourth nerve palsy and primary position upbeat-torsional nystagmus due to a small unilateral dorsal ponto-mesencephalic lymphomatous deposit. We postulate that the upbeat-torsional nystagmus was caused by involvement of the brachium conjunctivum, which lies adjacent to the fourth nerve fascicles at the dorsal ponto-mesencephalic junction, but we cannot exclude involvement of the crossing ventral tegmental tract. Our observations suggest that, in humans, excitatory upward-torsional eye movement signals from the anterior semicircular canals could be partly conveyed to the midbrain by the brachium conjunctivum. PMID:19645952

  4. [E. M. Jellinek - a "free floating" alcohologist].

    PubMed

    Kelemen, Gábor; Márk, Mónika

    2012-01-01

    This paper is divulging unpublished materials based on recent research on E. M. Jellinek who was the father of the scientific-medical agenda of alcohology. Results of our research in Hungarian archives not only open still unexplored realm for alcohol studies but also evoke fresh readings of its history. A good half of Jellinek's life has been uncharted and still contains terrain unbeknown to us. Following some infamous activity he fled from Hungary on the very same day (June 4, 1920) when the country lost two-thirds of its territory. After a ten-year roaming Jellinek's private Odyssey came to an end. He has started living his personal "American dream" in the country of his mother through the impersonal dream of alcohology, which was going to aspire to transform itself from a moral movement to an emerging interdisciplinary field of medicine. Jellinek had chosen to be uprooted and he managed to conceal his past in Budapest including his trans-generational past quite effectively. Authors have made an attempt to interpret the ambivalent tale and controversial personality of Jellinek embedded in the progress of alcohol studies. PMID:23180730

  5. Free-floating atmospheric pressure ball plasmas

    NASA Astrophysics Data System (ADS)

    Wurden, G. A.; Ticos, C.; Wang, Z.; Wurden, C. J. V.

    2007-11-01

    A long-lived (0.3 second, 10-20 cm diameter) ball plasma floating in the air above a water surface has been formed and studied in the laboratory. A 0.4 - 1 mF capacitor is charged to 4-5 kV, and subsequently discharged (30-60 Amps, 20-50 msec duration) into central copper cathode held fixed just below the surface of a bucket of water (with a weak solution of various salts in distilled water, such as CuSO4 or CuCl2, LiCl or NaCl). An underwater ring anode completes the circuit. A bubble of hot vapor from the water surface rises up in the first few milliseconds, and changes from a mushroom cloud with stalk, to a detached quasi-spherical object, finally evolving into a vortex ring. The plasma consists of ionized water vapor, with positive salts and OH- radicals, as well as molecular species, and it completely excludes nitrogen or oxygen from the rising plasma structure. A fine boundary layer is visible in orange, in contrast to a green ball interior when using Cu/CuSO4, and filamentary structures are visible at late times. Finally, a whisp of smoke ring is observed as a residue. A variety of visible and infrared imaging (both video and still cameras) are used, along with 200-800 nm time & space resolved spectroscopy, to identify features of this laboratory analog to ball lightning. Possible applications include a windowless ball- plasma powered pulsed copper vapor laser operating at 510 nm.

  6. Co-transplantation of carotid body and ventral mesencephalic cells as an alternative approach towards functional restoration in 6-hydroxydopamine-lesioned rats: implications for Parkinson's disease.

    PubMed

    Shukla, S; Agrawal, A K; Chaturvedi, R K; Seth, K; Srivastava, N; Sinha, C; Shukla, Y; Khanna, V K; Seth, P K

    2004-10-01

    Exogenous administration of various neurotrophic factors has been shown to protect neurons in animal model of Parkinson's disease (PD). Several attempts are being made to search a tissue source simultaneously expressing many of these neurotrophic factors. Carotid body (CB) contains oxygen-sensitive glomus cells rich in dopamine (DA) and expresses glial cell line-derived neurotrophic factor, brain-derived neurotrophic factor and neurotrophin-3. We have attempted to study the functional restoration following co-transplantation of CB cells and ventral mesencephalic cells (VMC) in a 6-hydroxydopamine-lesioned rat model of PD. A significant recovery (p < 0.001) in d-amphetamine-induced circling behavior (80%) and spontaneous locomotor activity (85%) was evident in co-transplanted animals at 12 weeks post-transplantation as compared to lesioned animals. Similarly, a significant (p < 0.001) restoration was observed in DA-D(2) receptor binding (77%), striatal DA (87%) and 3,4-dihydroxyphenylacetic acid (DOPAC) (85%) levels and nigral DA (75%) and DOPAC (74%) levels. Functional recovery was accompanied by tyrosine hydroxylase (TH) expression and quantification of TH-positive cells by image analysis revealed a significant restoration in TH-immunoreactive (IR) fiber density in striatum, as well as TH-IR neurons in substantia nigra pars compacta in co-transplanted animals over VMC-transplanted animals. The result suggests that co-transplantation of CB cells along with VMC provides better and long-term functional restoration in the rat model of PD, possibly by supporting the survival of newly grafted cells as well as remaining host DA neurons. PMID:15447661

  7. Mesencephalic astrocyte-derived neurotrophic factor reduces cell apoptosis via upregulating GRP78 in SH-SY5Y cells.

    PubMed

    Huang, Jingwei; Chen, Changyan; Gu, Hua; Li, Chen; Fu, Xing; Jiang, Ming; Sun, Hui; Xu, Jun; Fang, Jianmin; Jin, Lingjing

    2016-07-01

    Mesencephalic astrocyte-derived neurotrophic factor (MANF) protects dopaminergic neurons from damage. In this study, we used MTT, immunohistochemistry, and TUNEL staining to investigate the protective effect of MANF in SH-SY5Y cells treated with 6-OHDA or overexpressed α-synuclein. Cleaved caspase-3 levels significantly increased in cells treated with 6-OHDA or overexpressed α-synuclein. 6-OHDA or α-synuclein overexpression that induced cleaved caspase-3 levels to increase was reduced by MANF treatment. In addition, MANF treatment upregulated GRP78 expressions in cells treated with 6-OHDA or overexpressed α-synuclein, and RNAi knockdown for GRP78 could block the MANF induced cell survival from 6-OHDA treatment. Furthermore, GRP78 overexpression inhibited 6-OHDA-induced apoptosis. Our data suggest that MANF inhibits apoptosis induced by 6-OHDA and overexpressed α-synuclein in SH-SY5Y cells via upregulating GRP78 in the transcriptional pattern.

  8. Effects of the intra-arterial injection of bradykinin into the limbs, upon the activity of mesencephalic reticular units.

    PubMed

    Lombard, M C; Guilbaud, G; Besson, J M

    1975-02-01

    The changes in firing rate of mesencephalic reticular units after intra-arterial injection into the limbs of a potent nociceptive agent, bradykinin, were studied in cats (unanesthetized, immobilized with flaxedil and hyperventilated). 30 per cent of the d35 studied cells were affected, 56 per cent were excited, 23 per cent inhibited and 5 per cent had mixed effects. Among the 75 excited cells, the activation of 16 of them seemed to related to the arousa- processes (group A); for 56 cells the increase seemed dire-tly dependent on the nociceptive stimulation itself (group B). The changes of firing rate were repruducible; their latencies and durations were of the same order as the latencies and duration of the nociceptive reactions and painful sensation s, which have been obtained in animals and men after bradykinin injections. The modifications induced by bradykinin administration were suppressed by Ketamin and Thiopental.

  9. Intranigral grafts of fetal ventral mesencephalic tissue in adult 6-hydroxydopamine-lesioned rats can induce behavioral recovery.

    PubMed

    Johnston, R E; Becker, J B

    1997-01-01

    Intrastriatal grafts of fetal ventral mesencephalon in rats with unilateral 6-hydroxydopamine lesions can reduce and even reverse rotational behavior in response to direct and indirect dopamine agonists. These grafts can ameliorate deficits on simple spontaneous behaviors, but do not improve complex behaviors that require the skilled integration of the use of both paws. We report here that rats with grafts into the DA-depleted substantia nigra, that receive cyclosporine A, can experience recovery on spontaneous behaviors that mimic those observed in Parkinson's disease. Specific cyclosporine A treatment conditions can differentially affect whether intranigral grafts normalize paw use during initiation or termination of a movement sequence. These findings may have important implications for the treatment of Parkinson's disease. PMID:9171159

  10. Role of the cyclooxygenase 2-thromboxane pathway in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced decrease in mesencephalic vein blood flow in the zebrafish embryo

    SciTech Connect

    Teraoka, Hiroki Kubota, Akira; Dong, Wu; Kawai, Yusuke; Yamazaki, Koji; Mori, Chisato; Harada, Yoshiteru; Peterson, Richard E.; Hiraga, Takeo

    2009-01-01

    Previously, we reported that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) evoked developmental toxicity required activation of aryl hydrocarbon receptor type 2 (AHR2), using zebrafish embryos. However, the downstream molecular targets of AHR2 activation are largely unknown and are the focus of the present investigation. TCDD induces cyclooxygenase 2 (COX2), a rate-limiting enzyme for prostaglandin synthesis in certain cells. In the present study, we investigated the role of the COX2-thromboxane pathway in causing a specific endpoint of TCDD developmental toxicity in the zebrafish embryo, namely, a decrease in regional blood flow in the dorsal midbrain. It was found that the TCDD-induced reduction in mesencephalic vein blood flow was markedly inhibited by selective COX2 inhibitors, NS-398 and SC-236, and by a general COX inhibitor, indomethacin, but not by a selective COX1 inhibitor, SC-560. Gene knock-down of COX2 by two different types of morpholino antisense oligonucleotides, but not by their negative homologs, also protected the zebrafish embryos from mesencephalic vein circulation failure caused by TCDD. This inhibitory effect of TCDD on regional blood flow in the dorsal midbrain was also blocked by selective antagonists of the thromboxane receptor (TP). Treatment of control zebrafish embryos with a TP agonist also caused a reduction in mesencephalic vein blood flow and it too was blocked by a TP antagonist, without any effect on trunk circulation. Finally, gene knock-down of thromboxane A synthase 1 (TBXS) with morpholinos but not by the morpholinos' negative homologs provided significant protection against TCDD-induced mesencephalic circulation failure. Taken together, these results point to a role of the prostanoid synthesis pathway via COX2-TBXS-TP in the local circulation failure induced by TCDD in the dorsal midbrain of the zebrafish embryo.

  11. Morphological correlates of electrotonic coupling in the magnocellular mesencephalic nucleus of the weakly electric fish Gymnotus carapo.

    PubMed

    Sotelo, C; Réthelyi, M; Szabo, T

    1975-10-01

    The magnocellular mesencephalic nucleus (MMN) of Gymnotus carapo was studied by electron microscopy. This particular nucleus, characteristic of weakly electric fish, contains two principal classes of neuron. (1) Large neurons (25-35 mum): these are rounded unipolar cells, with the perikaryon partially covered by a sheath of compact myelin. The axon leaves the neuron as a short thick unmyelinated process not resembling the initial segment of multipolar neurons. The axon branches profusely and becomes myelinated very close to its origin. The perikaryal surface not covered by the myelin sheath receives abundant club endings. The synaptic interface between club endings and large neurons is characterized by alternating gap junctions and attachment plaques. In addition, at the periphery of the club endings, "active" zones are generally present, and this synapse is therefore a "mixed" synapse. (2) Small neurons (5-12 mum): these are uni- or bipolar cells, scattered throughout the nucleus, and occasionally, grouped in small clusters. Gap junctions were not observed between neuronal perikarya in such clusters. The synaptic investment of small neurons is formed by long cup endings which almost completely encircle the perikarya. The synaptic interface between cup endings and the perikarya of small neurons is characterized by large areas of gap junctions. A single cup ending establishing gap junctions with two small neurons within the plane of the section was frequently observed and this arrangement provides a morphological basis for electrotonic coupling between small neurons by way of presynaptic fibres. In the neuropil of the MMN, there are abundant synaptic islands constituted by a large axon terminal in synaptic contact with small unidentified profiles; both synaptic elements are surrounded by numerous thin glial lamellae. At the synaptic interface, in the islands, both gap junctions and "active" zones are present. The synaptic islands must also be considered as "mixed

  12. Enhanced proliferation and dopaminergic differentiation of ventral mesencephalic precursor cells by synergistic effect of FGF2 and reduced oxygen tension

    SciTech Connect

    Jensen, Pia; Gramsbergen, Jan-Bert; Zimmer, Jens; Widmer, Hans R.; Meyer, Morten

    2011-07-15

    Effective numerical expansion of dopaminergic precursors might overcome the limited availability of transplantable cells in replacement strategies for Parkinson's disease. Here we investigated the effect of fibroblast growth factor-2 (FGF2) and FGF8 on expansion and dopaminergic differentiation of rat embryonic ventral mesencephalic neuroblasts cultured at high (20%) and low (3%) oxygen tension. More cells incorporated bromodeoxyuridine in cultures expanded at low as compared to high oxygen tension, and after 6 days of differentiation there were significantly more neuronal cells in low than in high oxygen cultures. Low oxygen during FGF2-mediated expansion resulted also in a significant increase in tyrosine hydroxylase-immunoreactive (TH-ir) dopaminergic neurons as compared to high oxygen tension, but no corresponding effect was observed for dopamine release into the culture medium. However, switching FGF2-expanded cultures from low to high oxygen tension during the last two days of differentiation significantly enhanced dopamine release and intracellular dopamine levels as compared to all other treatment groups. In addition, the short-term exposure to high oxygen enhanced in situ assessed TH enzyme activity, which may explain the elevated dopamine levels. Our findings demonstrate that modulation of oxygen tension is a recognizable factor for in vitro expansion and dopaminergic differentiation of rat embryonic midbrain precursor cells.

  13. Anatomical Evidence that the Superior Colliculus Controls Saccades through Central Mesencephalic Reticular Formation Gating of Omnipause Neuron Activity

    PubMed Central

    Wang, Niping; Perkins, Eddie; Zhou, Lan; Warren, Susan

    2013-01-01

    Omnipause neurons (OPNs) within the nucleus raphe interpositus (RIP) help gate the transition between fixation and saccadic eye movements by monosynaptically suppressing activity in premotor burst neurons during fixation, and releasing them during saccades. Premotor neuron activity is initiated by excitatory input from the superior colliculus (SC), but how the tectum's saccade-related activity turns off OPNs is not known. Since the central mesencephalic reticular formation (cMRF) is a major SC target, we explored whether this nucleus has the appropriate connections to support tectal gating of OPN activity. In dual-tracer experiments undertaken in macaque monkeys (Macaca fascicularis), cMRF neurons labeled retrogradely from injections into RIP had numerous anterogradely labeled terminals closely associated with them following SC injections. This suggested the presence of an SC–cMRF–RIP pathway. Furthermore, anterograde tracers injected into the cMRF of other macaques labeled axonal terminals in RIP, confirming this cMRF projection. To determine whether the cMRF projections gate OPN activity, postembedding electron microscopic immunochemistry was performed on anterogradely labeled cMRF terminals with antibody to GABA or glycine. Of the terminals analyzed, 51.4% were GABA positive, 35.5% were GABA negative, and most contacted glycinergic cells. In summary, a trans-cMRF pathway connecting the SC to the RIP is present. This pathway contains inhibitory elements that could help gate omnipause activity and allow other tectal drives to induce the bursts of firing in premotor neurons that are necessary for saccades. The non-GABAergic cMRF terminals may derive from fixation units in the cMRF. PMID:24107960

  14. Evidence for a trigeminal mesencephalic-hypoglossal nuclei loop involved in controlling vibrissae movements in the rat.

    PubMed

    Mameli, Ombretta; Caria, Marcello Alessandro; Pellitteri, Rosalia; Russo, Antonella; Saccone, Salvatore; Stanzani, Stefania

    2016-03-01

    Previous studies performed in rats showed that the whisker-pad motor innervation involves not only the facial nerve, but also some hypoglossal neurons whose axons travel within the trigeminal infraorbital nerve (ION) and target the extrinsic muscles surrounding the whisker-pad macrovibrissae. Furthermore, the electrical stimulation of the ION induced an increase in the EMG activity of these muscles, while the hypoglossal nucleus stimulation elicited evoked potentials and single motor unit responses. However, the existence of a neural network able to involve the XIIth nucleus in macrovibrissae whisking control was totally unknown until now. Since other recent experiments demonstrated that: (1) the mesencephalic trigeminal nucleus (Me5) neurons respond to both spontaneous and artificial movements of macrovibrissae, and (2) the Me5 peripheral terminals provide a monosynaptic sensory innervation to the macrovibrissae, the present study was aimed at analyzing a possible role of the Me5 nucleus as a relay station in the sensory-motor loop that involves the XIIth nucleus neurons in rhythmic whisking control. Two tracers were used in the same animal: Fluoro Gold, which was injected into the whisker pad to retrogradely label the hypoglossal whisker-pad projection neurons, and Dil, which was instead injected into the Me5 to label its projections to these hypoglossal neurons. Results demonstrated that terminals of the Me5 neurons monosynaptically target the hypoglossal whisker-pad projection neurons. The functional role of this sensory-motor connection is discussed, with particular regard to a hypothesized proprioceptive reflex in whisker-pad extrinsic muscles that can be elicited by the activation of the Me5 macrovibrissae receptors. PMID:26645304

  15. Neuroprotective role of thymoquinone against 1-methyl-4-phenylpyridinium-induced dopaminergic cell death in primary mesencephalic cell culture

    PubMed Central

    Radad, Khaled S.; Al-Shraim, Mubarak M.; Moustafa, Mahmoud F.; Rausch, Wolf-Dieter

    2015-01-01

    Objectives: To investigate potential mechanisms mediating the neuroprotective effect of thymoquinone (TQ) on dopaminergic neurons. Methods: This study was conducted in the Chemistry and Biochemistry Institute, University of Veterinary Medicine, Vienna, Austria between June and August 2013. Primary cultures were prepared from embryonic mouse mesencephala (OFI/SPF) at gestation day 14. Four sets of cultures were kept untreated, treated with TQ on the eighth day in vitro (DIV) for 4 days, treated with 1-methyl-4-phenylpyridinium (MPP+) on the tenth DIV for 48 hours and co-treated with thymoquinone and MPP+. On the twelfth DIV, cultures were subjected to immunohistochemistry against tyrosine hydroxylase and fluorescent staining using LysoTracker® Deep Red, 5,5’,6,6’-tetrachloro-1,1’,3,3’-tetraethyl benzimidazolylcarbocyanine (JC-1) and 4’,6-diamidino-2-phenylindole stains. Results: The MPP+ decreased the number of dopaminergic neurons by 40%, and increased the release of lactate dehydrogenase (LDH) into the culture medium. The TQ significantly rescued dopaminergic neurons and decreased the release of LDH at the concentrations of 0.1 and 1 µM. The TQ significantly shifted the red fluorescent intensity of the LysoTracker® Deep Red, increased the mitochondrial membrane potential as it increased the red:green florescent ratio of JC-1, and decreased MPP+-induced apoptotic cell death. Conclusion: The TQ protects dopaminergic neurons in primary mesencephalic culture by enhancing lysosomal degradation that clears damaged mitochondria and inhibits mitochondria-mediated apoptotic cell death. PMID:25630775

  16. Signaling Mechanisms in the Nitric Oxide Donor- and Amphetamine-Induced Dopamine Release in Mesencephalic Primary Cultured Neurons.

    PubMed

    Salum, Cristiane; Schmidt, Fanny; Michel, Patrick P; Del-Bel, Elaine; Raisman-Vozari, Rita

    2016-01-01

    Previous research has shown that nitric oxide (NO) synthase inhibitors prevent rodents' sensorimotor gating impairments induced by dopamine releasing drugs, such as amphetamine (Amph) and methylphenidate. The mechanisms of this effect have not been entirely understood. In the present work, we investigated some possible mechanisms by which the NO donor, NOC-12 (3-ethyl-3-(ethylaminoethyl)-1-hydroxy-2-oxo-1-triazene), influence spontaneous and Amph-induced dopamine release, using rat mesencephalic primary cultured neurons preparations. Our results showed that NOC-12 increased dopamine release in a concentration-dependent manner and potentiated the Amph-induced one. Dopamine release induced by NOC-12 was disrupted by N-acetyl-L-cystein (NAC-a free radical scavenger) and MK-801, a NMDA (N-methyl-D-aspartate) non-competitive antagonist, and was concentration dependently affected by oxadiazolo[4,3]quinoxalin-1-one, an inhibitor of the soluble guanylate cyclase (sGC). In contrast, dopamine released by Amph was facilitated by NAC and by MK-801 and not affected by nifedipine (a L-type-Ca(+2) channel blocker), which enhanced NOC-12-induced dopamine release. The present work demonstrates that DA release induced by NOC-12 is partially dependent on sGC and on NMDA activation, and is modulated by L-type Ca(+2) channel and the antioxidant NAC. This mechanism differs from the Amph-induced one, which appears not to depend on L-type Ca(+2) channel and seems to be facilitated by NMDA channel blocking and by NAC. These results suggest that Amph and NOC-12 induce dopamine release through complementary pathways, which may explain the potentiation of Amph-induced dopamine release by NOC-12. These findings contribute to understand the involvement of NO in dopamine-related neuropsychiatric and neurodegenerative diseases.

  17. Role of zebrafish cytochrome P450 CYP1C genes in the reduced mesencephalic vein blood flow caused by activation of AHR2

    SciTech Connect

    Kubota, Akira; Stegeman, John J.; Woodin, Bruce R.; Iwanaga, Toshihiko; Harano, Ryo; Peterson, Richard E.; Hiraga, Takeo; Teraoka, Hiroki

    2011-06-15

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various signs of toxicity in early life stages of vertebrates through activation of the aryl hydrocarbon receptor (AHR). We previously reported a sensitive and useful endpoint of TCDD developmental toxicity in zebrafish, namely a decrease in blood flow in the dorsal midbrain, but downstream genes involved in the effect are not known. The present study addressed the role of zebrafish cytochrome P450 1C (CYP1C) genes in association with a decrease in mesencephalic vein (MsV) blood flow. The CYP1C subfamily was recently discovered in fish and includes the paralogues CYP1C1 and CYP1C2, both of which are induced via AHR2 in zebrafish embryos. We used morpholino antisense oligonucleotides (MO or morpholino) to block initiation of translation of the target genes. TCDD-induced mRNA expression of CYP1Cs and a decrease in MsV blood flow were both blocked by gene knockdown of AHR2. Gene knockdown of CYP1C1 by two different morpholinos and CYP1C2 by two different morpholinos, but not by their 5 nucleotide-mismatch controls, was effective in blocking reduced MsV blood flow caused by TCDD. The same CYP1C-MOs prevented reduction of blood flow in the MsV caused by {beta}-naphthoflavone (BNF), representing another class of AHR agonists. Whole-mount in situ hybridization revealed that mRNA expression of CYP1C1 and CYP1C2 was induced by TCDD most strongly in branchiogenic primordia and pectoral fin buds. In situ hybridization using head transverse sections showed that TCDD increased the expression of both CYP1Cs in endothelial cells of blood vessels, including the MsV. These results indicate a potential role of CYP1C1 and CYP1C2 in the local circulation failure induced by AHR2 activation in the dorsal midbrain of the zebrafish embryo. - Research Highlights: > We examine the roles of zebrafish CYP1C1 and CYP1C2 in TCDD developmental toxicity. > TCDD induces mRNA expression of both CYP1Cs in the mesencephalic vein. > Knockdown of each

  18. Enhanced differentiation of neural progenitor cells into neurons of the mesencephalic dopaminergic subtype on topographical patterns.

    PubMed

    Tan, Kenneth K B; Tann, Jason Y; Sathe, Sharvari R; Goh, Seok Hong; Ma, Dongliang; Goh, Eyleen L K; Yim, Evelyn K F

    2015-03-01

    Parkinson's disease (PD) is a neurodegenerative disease attributed to the loss of midbrain dopaminergic (DA) neurons. The current lack of predictive models for this disease has been hampered by the acquirement of robust cells, posing a major barrier to drug development. Differentiation of stem cells into subtype specific cells may be guided by appropriate topographical cues but the role of topography has hitherto not been well understood. We used a Multi-Architecture (MARC) chip with various topographical structures and identified three topographies, which generate DA neurons from murine hippocampal neural progenitor cells with the highest percentage of neuronal (β-III-tubulin positive) and dopaminergic (tyrosine hydroxylase positive) populations. Analysis on single pattern structures showed that 2 μm gratings with 2 μm spacing and 2 μm height (2 μm gratings) and 2 μm gratings with hierarchical structure produced cells with the highest gene expression of TH and PITX3, with the longest neurite and highest percentage of alignment. Quantitative image analysis showed the 2 μm gratings produced cells with the highest expression of pituitary homeobox 3 (PITX3), LIM homeobox transcription factor 1 alpha (LMX1a), aldehyde dehydrogenase 1 family member A1 (ALDH1a1) and microtubule associated protein 2 (MAP2), as compared to nano-gratings and unpatterned controls. These patterns also enhance DA neuron differentiation on different substrate rigidities, as seen on both poly-dimethylsiloxane (PDMS) and tissue culture polystyrene (TCPS) substrates. These results show the use of topographical influence for neuronal subtype specification, which could be translated into a wide range of clinical applications for PD. PMID:25591959

  19. Mobile encapsulated bodies comprising fat necrosis and fibrous tissue in the abdominal cavity of cows.

    PubMed

    Herzog, K; Burgdorf, W; Hewicker-Trautwein, M

    2010-11-01

    The microscopical features of 18 samples of fat necrosis and/or fibrous tissue removed from the abdominal cavity during laparotomy from 15 cows were studied. The nodular, ivory-coloured mobile structures were free-floating in the abdominal cavity, were not attached to any abdominal tissues or organs, and were completely surrounded by a fibrous capsule. Abdominal fat necrosis (bovine lipomatosis) was not observed in any animal. The structures comprised either necrotic fat, fibrous tissue or varying proportions of both. Focal calcification and mild inflammatory cell infiltration and accumulations of haemosiderin were also present. Microscopically, the lesions resembled encapsulated fat necrosis occurring in human subcutaneous tissue. The mechanisms of development of these mobile encapsulated bodies in cows is unknown and it is not clear how, in the absence of a blood supply, there can be inflammatory cell infiltration, calcification and proliferation of fibroblasts.

  20. A New Antigen Retrieval Technique for Human Brain Tissue

    PubMed Central

    Byne, William; Haroutunian, Vahram; García-Villanueva, Mercedes; Rábano, Alberto; García-Amado, María; Prensa, Lucía; Giménez-Amaya, José Manuel

    2008-01-01

    Immunohistochemical staining of tissues is a powerful tool used to delineate the presence or absence of an antigen. During the last 30 years, antigen visualization in human brain tissue has been significantly limited by the masking effect of fixatives. In the present study, we have used a new method for antigen retrieval in formalin-fixed human brain tissue and examined the effectiveness of this protocol to reveal masked antigens in tissues with both short and long formalin fixation times. This new method, which is based on the use of citraconic acid, has not been previously utilized in brain tissue although it has been employed in various other tissues such as tonsil, ovary, skin, lymph node, stomach, breast, colon, lung and thymus. Thus, we reported here a novel method to carry out immunohistochemical studies in free-floating human brain sections. Since fixation of brain tissue specimens in formaldehyde is a commonly method used in brain banks, this new antigen retrieval method could facilitate immunohistochemical studies of brains with prolonged formalin fixation times. PMID:18852880

  1. Cell bodies of the trigeminal proprioceptive neurons that transmit reflex contraction of the levator muscle are located in the mesencephalic trigeminal nucleus in rats.

    PubMed

    Fujita, Kenya; Matsuo, Kiyoshi; Yuzuriha, Shunsuke; Kawagishi, Kyutaro; Moriizumi, Tetsuji

    2012-12-01

    Since the levator and frontalis muscles lack interior muscle spindles despite being antigravity mixed muscles to involuntarily sustain eyelid opening and eyebrow lifting, this study has proposed a hypothetical mechanism to compensate for this anatomical defect. The voluntary contraction of fast-twitch fibres of the levator muscle stretches the mechanoreceptors in Müller's muscle to evoke proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study confirmed the presence of cell bodies of the trigeminal proprioceptive neurons that transmit reflex contraction of the levator and frontalis muscles. After confirming that severing the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induced ipsilateral eyelid ptosis, Fluorogold was applied as a tracer to the proximal stump of the trigeminal proprioceptive nerve in rats. Fluorogold labelled the cell bodies of the trigeminal proprioceptive neurons, not in any regions of the rat brain including the trigeminal ganglion, but in the ipsilateral mesencephalic trigeminal nucleus neighbouring the locus ceruleus. Some Fluorogold particles accumulated in the area of the locus ceruleus. The trigeminal proprioceptive neurons could be considered centrally displaced ganglion cells to transmit afferent signal from the mechanoreceptors in Müller's muscle to the mesencephalon, where they may be able to make excitatory synaptic connections with both the oculomotor neurons and the frontalis muscle motoneurons for the involuntary coordination of the eyelid and eyebrow activities, and potentially to the locus ceruleus.

  2. Curcumin exerts anti-inflammatory and antioxidative properties in 1-methyl-4-phenylpyridinium ion (MPP(+))-stimulated mesencephalic astrocytes by interference with TLR4 and downstream signaling pathway.

    PubMed

    Yu, Song; Wang, Xu; He, Xingliang; Wang, Yue; Gao, Sujie; Ren, Lu; Shi, Yan

    2016-07-01

    Neuroinflammation is closely associated with the pathophysiology of neurodegenerative diseases including Parkinson's disease (PD). Recent evidence indicates that astrocytes also play pro-inflammatory roles in the central nervous system (CNS) by activation with toll-like receptor (TLR) ligands. Therefore, targeting anti-inflammation may provide a promising therapeutic strategy for PD. Curcumin, a polyphenolic compound isolated from Curcuma longa root, has been commonly used for the treatment of neurodegenerative diseases. However, the details of how curcumin exerts neuroprotection remain uncertain. Here, we investigated the protective effect of curcumin on 1-methyl-4-phenylpyridinium ion-(MPP(+)-) stimulated primary astrocytes. Our results showed that MPP(+) stimulation resulted in significant production of tumor necrosis factor (TNF)-α, interleukin (IL-6), and reactive oxygen species (ROS) in primary mesencephalic astrocytes. Curcumin pretreatment decreased the levels of these pro-inflammatory cytokines while increased IL-10 expression in MPP(+)-stimulated astrocytes. In addition, curcumin increased the levels of antioxidant glutathione (GSH) and reduced ROS production. Our results further showed that curcumin decreased the levels of TLR4 and its downstream effectors including NF-κB, IRF3, MyD88, and TIRF that are induced by MPP(+) as well as inhibited the immunoreactivity of TLR4 and morphological activation in MPP(+)-stimulated astrocytes. Together, data suggest that curcumin might exert a beneficial effect on neuroinflammation in the pathophysiology of PD. PMID:27164829

  3. Inhibitory and excitatory amino acid neurotransmitters are utilized by the projection from the dorsal deep mesencephalic nucleus to the sublaterodorsal nucleus REM sleep induction zone.

    PubMed

    Liang, Chang-Lin; Quang Nguyen, Tin; Marks, Gerald A

    2014-06-01

    The sublaterodorsal nucleus (SLD) in the pons of the rat is a locus supporting short-latency induction of a REM sleep-like state following local application of a GABAA receptor antagonist or kainate, glutamate receptor agonist. One putatively relevant source of these neurotransmitters is from the region of the deep mesencephalic nucleus (DpMe) just ventrolateral to the periaquiductal gray, termed the dorsal DpMe (dDpMe). Here, the amino acid neurotransmitter innervation of SLD from dDpMe was studied utilizing anterograde tract-tracing with biotinylated dextranamine (BDA) and fluorescence immunohistochemistry visualized with laser scanning confocal microscopy. Both markers for inhibitory and excitatory amino acid neurotransmitters were found in varicose axon fibers in SLD originating from dDpMe. Vesicular glutamate transporter2 (VGLUT2) represented the largest number of anterogradely labeled varicosities followed by vesicular GABA transporter (VGAT). Numerous VGAT and VGLUT2 labeled varicosities were observed apposed to dDpMe-labeled axon fibers indicating both excitatory and inhibitory presynaptic, local modulation within the SLD. Some double-labeled BDA/VGAT varicosities were seen apposed to small somata labeled for glutamate consistent with being presynaptic to the phenotype of REM sleep-active SLD neurons. Results found support the current theoretical framework of the interaction of dDpMe and SLD in control of REM sleep, while also indicating operation of mechanisms with a greater level of complexity.

  4. Immune modulation by MANF promotes tissue repair and regenerative success in the retina.

    PubMed

    Neves, Joana; Zhu, Jie; Sousa-Victor, Pedro; Konjikusic, Mia; Riley, Rebeccah; Chew, Shereen; Qi, Yanyan; Jasper, Heinrich; Lamba, Deepak A

    2016-07-01

    Regenerative therapies are limited by unfavorable environments in aging and diseased tissues. A promising strategy to improve success is to balance inflammatory and anti-inflammatory signals and enhance endogenous tissue repair mechanisms. Here, we identified a conserved immune modulatory mechanism that governs the interaction between damaged retinal cells and immune cells to promote tissue repair. In damaged retina of flies and mice, platelet-derived growth factor (PDGF)-like signaling induced mesencephalic astrocyte-derived neurotrophic factor (MANF) in innate immune cells. MANF promoted alternative activation of innate immune cells, enhanced neuroprotection and tissue repair, and improved the success of photoreceptor replacement therapies. Thus, immune modulation is required during tissue repair and regeneration. This approach may improve the efficacy of stem-cell-based regenerative therapies. PMID:27365452

  5. Artificial design of three-dimensional retina-like tissue from dissociated cells of the mammalian retina by rotation-mediated cell aggregation.

    PubMed

    Rothermel, Andrée; Biedermann, Thomas; Weigel, Winnie; Kurz, Randy; Rüffer, Markus; Layer, Paul G; Robitzki, Andrea Anneliese

    2005-01-01

    The goal of this study was to establish a reliable three-dimensional culture system for the mammalian retina that allows the analysis of retinal function and dysfunction. To produce three-dimensional retinal tissues in vitro, dissociated retinal cells of neonatal rats were maintained in culture dishes on a self-made orbital shaker. On the basis of well-defined rotation conditions, dissociated free-floating cells reaggregate in the center of the culture dish to form a multicellular cluster. Subsequently, cells begin to proliferate, whereby they form spherelike retinal tissues that grow to a size of 180-210 microm. Immunohistochemical characterization of mature retinal spheres revealed the presence of ganglion cells, amacrine cells, Müller cells, and rod photoreceptors, which are arranged in different retina-like layers. Although a small number of cells undergo programmed cell death, retinal spheres remain viable for at least 35 days in culture as revealed by fluorescein diacetate and TUNEL staining. Because most biological processes involved in tissue organization such as proliferation, differentiation, apoptosis, and survival are also observable in retinal spheres, the presented novel mammalian three-dimensional culture system is not only an outstanding model for basic research but may also be of great benefit for stem cell tissue engineering and the pharmaceutical industry.

  6. Properties of dopaminergic neurons in organotypic mesencephalic-striatal co-cultures--evidence for a facilitatory effect of dopamine on the glutamatergic input mediated by α-1 adrenergic receptors.

    PubMed

    Cucchiaroni, Maria L; Freestone, Peter S; Berretta, Nicola; Viscomi, Maria T; Bisicchia, Elisa; Okano, Hideyuki; Molinari, Marco; Bernardi, Giorgio; Lipski, Janusz; Mercuri, Nicola B; Guatteo, Ezia

    2011-05-01

    Organotypic cultures (OCs) have been widely used to investigate the midbrain dopaminergic system, but only a few studies focused on the functional properties of dopaminergic neurons and their synaptic inputs from dopaminergic and non-dopaminergic neurons also contained in such cultures. In addition, it is not clear whether the culturing process affects the intrinsic neuronal properties and the expression of specific receptors and transporters. We performed patch-clamp recordings from dopaminergic neurons in mesencephalic-striatal co-cultures obtained from transgenic mice expressing green fluorescent protein (GFP) under the tyrosine hydroxylase promoter. Some (10/44) GFP+ neurons displayed a bursting activity that renders the firing of these cells similar to that of the dopaminergic neurons in vivo. The culturing process reduced the hyperpolarization-activated current (I(h) ) and the expression of D₂ receptors. Downregulation of D₂ receptor mRNA and protein was confirmed with reverse transcriptase polymerase chain reaction and Western blotting. Immunocytochemistry revealed that many synaptic terminals, most likely originating from dopaminergic neurons, co-expressed the dopamine (DA) transporter and the vesicular glutamate transporter-2, suggesting a co-release of DA and glutamate. Interestingly, exogenous DA decreased glutamate release in young cultures [days in vitro (DIV)<20] by acting on pre-synaptic D₂ receptors, while in older cultures (DIV>26) DA increased glutamate release by acting on α-1 adrenoreceptors. The facilitatory effect of DA on glutamatergic transmission to midbrain dopaminergic neurons may be important in conditions when the expression of D₂ receptors is compromised, such as long-term treatment with antipsychotic drugs. Our data show that midbrain OCs at DIV>26 may provide a suitable model of such conditions.

  7. Tissue types (image)

    MedlinePlus

    There are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports other tissues and binds them together (bone, blood, and lymph tissues). Epithelial tissue ...

  8. Autologous Adrenal Medullary, Fetal Mesencephalic, and Fetal Adrenal Brain Transplantation in Parkinson's Disease: A Long-Term Postoperative Follow-Up

    PubMed Central

    Madrazo, Ignacio; Franco-Bourland, Rebecca; Aguilera, Maricarmen; Ostrosky-Solis, Feggy; Madrazo, Mario; Cuevas, Carlos; Catrejon, Hugo; Guizar-Zahagun, Gabriel; Magallon, Eduardo

    1991-01-01

    We report on the clinical status of 5 patients with Parkinson's disease (PD) 3 years after autologous adrenal medullary (AM)-to-caudate nucleus (CN) implanfion, and of 2 PD patients, 2 years after fetal ventral mesencephalon (VM)- and fetal adrenal (A)-to-CN homotransplantation. Current clinical evaluation of 4 of the AM grafted patients revealed sustained bilateral amelioration of their PD signs, most notably of rgidity, postural imbalance and gait disturbances, resulting in a substantial improvement in their quality of life. the disease-related dystonia of one of them disappeared only 2 years after surgery. The levodopa requirements of 2 of these patients and the anticholinergic therapy of another have been reduced. In agreement with the satisfactory clinical evaluation of these 4 patients, their neuropsychological and electrophysiological improvements, initially registered 3 months after surgery, have been maintained for 3 years. After 1 year of significant recovery, the 5th patient of this group has almost returned to her preoperative state. The 2 homotransplanted patients also showed sustained bilateral improvement of their PD signs. Two years after surgery, the most improved signs of the fetal VM case were rigidity, bradykinesia, postural imbalance, gait disturbances and facial expression. The fetal A case has only shown amelioration of rigidity and bradykinesia. Neither of them has shown significant neuropsychological changes. Their current levodopa requirements are less than before surgery. The improvements shown here by PD patients after brain tissue grafts go beyond those obtained using any other therapeutic approach, when levodopa fails. Although more studies and the development of these procedures are obviously required, these initial human trials appear to be resisting the test of time. PMID:1782251

  9. Optimising contraction and alignment of cellular collagen hydrogels to achieve reliable and consistent engineered anisotropic tissue.

    PubMed

    O'Rourke, Caitriona; Drake, Rosemary A L; Cameron, Grant W W; Loughlin, A Jane; Phillips, James B

    2015-11-01

    Engineered anisotropic tissue constructs containing aligned cell and extracellular matrix structures are useful as in vitro models and for regenerative medicine. They are of particular interest for nervous system modelling and regeneration, where tracts of aligned neurons and glia are required. The self-alignment of cells and matrix due to tension within tethered collagen gels is a useful tool for generating anisotropic tissues, but requires an optimal balance between cell density, matrix concentration and time to be achieved for each specific cell type. The aim of this study was to develop an assay system based on contraction of free-floating cellular gels in 96-well plates that could be used to investigate cell-matrix interactions and to establish optimal parameters for subsequent self-alignment of cells in tethered gels. Using C6 glioma cells, the relationship between contraction and alignment was established, with 60-80% contraction in the 96-well plate assay corresponding to alignment throughout tethered gels made using the same parameters. The assay system was used to investigate the effect of C6 cell density, collagen concentration and time. It was also used to show that blocking α1 integrin reduced the contraction and self-alignment of these cells, whereas blocking α2 integrin had little effect. The approach was validated by using primary astrocytes in the assay system under culture conditions that modified their ability to contract collagen gels. This detailed investigation describes a robust assay for optimising cellular self-alignment and provides a useful reference framework for future development of self-aligned artificial tissue.

  10. A Wnt1 regulated Frizzled-1/β-Catenin signaling pathway as a candidate regulatory circuit controlling mesencephalic dopaminergic neuron-astrocyte crosstalk: Therapeutical relevance for neuron survival and neuroprotection

    PubMed Central

    2011-01-01

    Background Dopamine-synthesizing (dopaminergic, DA) neurons in the ventral midbrain (VM) constitute a pivotal neuronal population controlling motor behaviors, cognitive and affective brain functions, which generation critically relies on the activation of Wingless-type MMTV integration site (Wnt)/β-catenin pathway in their progenitors. In Parkinson's disease, DA cell bodies within the substantia nigra pars compacta (SNpc) progressively degenerate, with causes and mechanisms poorly understood. Emerging evidence suggests that Wnt signaling via Frizzled (Fzd) receptors may play a role in different degenerative states, but little is known about Wnt signaling in the adult midbrain. Using in vitro and in vivo model systems of DA degeneration, along with functional studies in both intact and SN lesioned mice, we herein highlight an intrinsic Wnt1/Fzd-1/β-catenin tone critically contributing to the survival and protection of adult midbrain DA neurons. Results In vitro experiments identifie Fzd-1 receptor expression at a mRNA and protein levels in dopamine transporter (DAT) expressing neurons, and demonstrate the ability of exogenous Wnt1 to exert robust neuroprotective effects against Caspase-3 activation, the loss of tyrosine hydroxylase-positive (TH+) neurons and [3H] dopamine uptake induced by different DA-specific insults, including serum and growth factor deprivation, 6-hydroxydopamine and MPTP/MPP+. Co-culture of DA neurons with midbrain astrocytes phenocopies Wnt1 neuroprotective effects, whereas RNA interference-mediated knockdown of Wnt1 in midbrain astrocytes markedly reduces astrocyte-induced TH+ neuroprotection. Likewise, silencing β-catenin mRNA or knocking down Fzd-1 receptor expression in mesencephalic neurons counteract astrocyte-induced TH+ neuroprotection. In vivo experiments document Fzd-1 co-localization with TH+ neurons within the intact SNpc and blockade of Fzd/β-catenin signaling by unilateral infusion of a Fzd/β-catenin antagonist within the SN

  11. Diazepam binding inhibitor gene expression: Location in brain and peripheral tissues of rate

    SciTech Connect

    Alho, H.; Fremeau, R.T. Jr.; Tiedge, H.; Wilcox, J.; Bovolin, P.; Brosius, J.; Roberts, J.L.; Costa, E.

    1988-09-01

    Diazepam binding inhibitor (DBI), an endogenous 10-kDa polypeptide was isolated from rat and human brain by monitoring displacement of radioactive diazepam bound to specific recognition sites in brain synaptic and mitochondrial membranes. The cellular location of DBI mRNA was studied in rat brain and selected peripheral tissues by in situ hybridization histochemistry with a /sup 35/S-labeled single-stranded complementary RNA probe. DBI mRNA was heterogeneously distributed in rat brain, with particularly high levels in the area postrema, the cerebellar cortex, and ependyma of the third ventricle. Intermediate levels were found in the olfactory bulb, pontine nuclei, inferior colliculi, arcuate nucleus, and pineal gland. Relatively low but significant levels of silver grains were observed overlying many mesencephalic and telencephalic areas that have previously been shown to contain numerous DBI-immunoreactive neurons and a high density of central benzodiazepine receptors. In situ hybridizations also revealed high levels of DBI mRNA in the posterior lobe of the pituitary gland, liver, and germinal center of the white pulp of spleen, all tissues that are rich in peripheral benzodiazepine binding sites. The tissue-specific pattern of DBI gene expression described here could be exploited to further understand the physiological function of DBI in the brain and periphery.

  12. Tissue Microarrays.

    PubMed

    Dancau, Ana-Maria; Simon, Ronald; Mirlacher, Martina; Sauter, Guido

    2016-01-01

    Modern next-generation sequencing and microarray technologies allow for the simultaneous analysis of all human genes on the DNA, RNA, miRNA, and methylation RNA level. Studies using such techniques have lead to the identification of hundreds of genes with a potential role in cancer or other diseases. The validation of all of these candidate genes requires in situ analysis of high numbers of clinical tissues samples. The tissue microarray technology greatly facilitates such analysis. In this method minute tissue samples (typically 0.6 mm in diameter) from up to 1000 different tissues can be analyzed on one microscope glass slide. All in situ methods suitable for histological studies can be applied to TMAs without major changes of protocols, including immunohistochemistry, fluorescence in situ hybridization, or RNA in situ hybridization. Because all tissues are analyzed simultaneously with the same batch of reagents, TMA studies provide an unprecedented degree of standardization, speed, and cost efficiency.

  13. Tissue Tregs.

    PubMed

    Panduro, Marisella; Benoist, Christophe; Mathis, Diane

    2016-05-20

    The immune system is responsible for defending an organism against the myriad of microbial invaders it constantly confronts. It has become increasingly clear that the immune system has a second major function: the maintenance of organismal homeostasis. Foxp3(+)CD4(+) regulatory T cells (Tregs) are important contributors to both of these critical activities, defense being the primary purview of Tregs circulating through lymphoid organs, and homeostasis ensured mainly by their counterparts residing in parenchymal tissues. This review focuses on so-called tissue Tregs. We first survey existing information on the phenotype, function, sustaining factors, and human equivalents of the three best-characterized tissue-Treg populations-those operating in visceral adipose tissue, skeletal muscle, and the colonic lamina propria. We then attempt to distill general principles from this body of work-as concerns the provenance, local adaptation, molecular sustenance, and targets of action of tissue Tregs, in particular.

  14. A new free-floating planet in the Upper Scorpius association

    NASA Astrophysics Data System (ADS)

    Peña Ramírez, K.; Béjar, V. J. S.; Zapatero Osorio, M. R.

    2016-02-01

    We report on a deep photometric survey covering an area of 1.17 deg2 in the young Upper Scorpius stellar association using VIMOS Iz and UKIDSS ZJHK data that was taken with several years in between. The search for the least massive population of Upper Scorpius (~5-10 Myr, 145 pc) is performed on the basis of various optical and infrared color-color and color-magnitude diagrams, including WISE photometry, in the magnitude interval J = 14.5-19 mag (completeness), which corresponds to substellar masses from 0.028 through 0.004 M⊙ at the age and distance of Upper Scorpius. We also present the proper motion analysis of the photometric candidates, finding that two objects successfully pass all photometric and astrometric criteria for membership in the young stellar association. One of them, USco J155150.2-213457, is a new discovery. We obtained low resolution, near-infrared spectroscopy (R ~ 450, 0.85-2.35 μm) of this new finding using the FIRE instrument. We confirmed its low-gravity atmosphere expected for an Upper Scorpius member (weak alkaline lines, strong VO absorption, peaked H-band pseudocontinuum). By comparison with spectroscopic standards, we derive a spectral type of L6 ± 1, and estimate a mass of ≈0.008-0.010 M⊙ for USco J155150.2-213457. The colors and spectral slope of this object resemble those of other young, cool members of Upper Scorpius and σ Orionis (~3 Myr) and field, high gravity dwarfs of related classification in contrast with the very red indices of field, low gravity, L-type dwarfs of intermediate age. USco J155150.2-213457, which does not show infrared flux excesses up to 4.5 μm, becomes one of the least massive and latest type objects known in the entire Upper Scorpius stellar association.

  15. Current-Sensitive Path Planning for an Underactuated Free-Floating Ocean Sensorweb

    NASA Technical Reports Server (NTRS)

    Dahl, Kristen P.; Thompson, David R.; McLaren, David; Chao, Yi; Chien, Steve

    2011-01-01

    This work investigates multi-agent path planning in strong, dynamic currents using thousands of highly under-actuated vehicles. We address the specific task of path planning for a global network of ocean-observing floats. These submersibles are typified by the Argo global network consisting of over 3000 sensor platforms. They can control their buoyancy to float at depth for data collection or rise to the surface for satellite communications. Currently, floats drift at a constant depth regardless of the local currents. However, accurate current forecasts have become available which present the possibility of intentionally controlling floats' motion by dynamically commanding them to linger at different depths. This project explores the use of these current predictions to direct float networks to some desired final formation or position. It presents multiple algorithms for such path optimization and demonstrates their advantage over the standard approach of constant-depth drifting.

  16. Free-Floating DNA: A New Strand of Technology from the Old Spool of Thought.

    ERIC Educational Resources Information Center

    Wegmann, Larry

    1989-01-01

    A procedure for extracting DNA from yeast using common reagents and equipment is given. Suggestions for variations are provided. A second activity for building a model of DNA from toothpicks is included. (CW)

  17. Microbial Characterization of Free Floating Condensate Aboard the Mir Space Station

    NASA Technical Reports Server (NTRS)

    Ott, C. M.; Bruce, R. J.; Pierson, D. L.

    2004-01-01

    Three samples of humidity condensate that had accumulated behind panels aboard the Russian space station Mir were collected and returned to earth for analysis. As these floating masses of liquid come into contact with the astronauts and the engineering systems, they have the potential to affect both crew health and systems performance. Using a combination of culturing techniques, a wide variety of organisms were isolated included Escherichia coli, Serratia marcescens, and a presumed Legionella species. In addition, microscopic analysis indicated the presence of protozoa, dust mites, and spirochetes. These findings suggest the need for more comprehensive microbial analysis of the environment through the use of new methodologies to allow a more thorough risk assessment of spacecraft. Copyright 2004 Springer-Verlag.

  18. Postmodern research: no grounding or privilege, just free-floating trouble making.

    PubMed

    Traynor, M

    1997-06-01

    Postmodernism has been criticized as failing to offer, on the one hand, authoritative explanations for social phenomena that might provide a scientific basis for policy formation or, on the other, the philosophical justification for emancipatory work-its radical scepticism about claims to knowledge leaving its advocates, including many nurses, with little scope to transform oppressive social and political regimes. Various approaches to this important problem have been offered, both philosophical and methodological. Some critical theorists have rejected certain aspects of postmodernism as dangerous and distracting. Some more accommodating solutions are troubled by unacknowledged inconsistencies. Others embrace postmodernism's unavoidable ambiguity (towards the Enlightenment for instance) with a lighter heart. In this paper I will review some of the criticism of postmodernism and some proposed solutions to these problems. Using recent research into the impact of managerialism on nursing within the UK National Health Service as an example and drawing on deconstructive literary theory, I conclude by accepting a rhetorical agonistics of undecidability. I take postmodernism as a mandate for causing trouble for those groups who are currently having their say and whose version of truth and rationality has achieved domination over others. I do not take postmodernism as a place from which to champion the cause or privilege the view of any particular group. PMID:9224046

  19. Fatal evolution of a huge right atrial free-floating thrombus

    PubMed Central

    Bodian, Malick; Ba, Fatimata G; Jobe, Modou; Ndiaye, Mouhamadou B; Kane, Adama; Sarr, Simon A; Mbaye, Alassane; Gaye, Abdou M; Thiam, Ibou; Diao, Maboury; Sarr, Moustapha; Bâ, Serigne A

    2013-01-01

    Key Clinical Message Right atrial thrombus is a rare medical emergency that should be suspected in all cases of pulmonary embolism, and rapid action should be taken to ensure a timely, proper management. PMID:25356214

  20. Tissue Issues

    ERIC Educational Resources Information Center

    Metz, James

    2016-01-01

    Every day, 27,000 trees are used to make bathroom tissue. Americans use an average of 23.6 rolls per person per year, and more than 7 billion rolls of toilet paper are sold yearly in the United States alone. Perhaps the amount of bathroom tissue used can be reduced by changing the dimensions of the paper or the core. This brief article presents…

  1. Unilateral asterixis associated with a mesencephalic syndrome.

    PubMed

    Tarsy, D; Lieberman, B; Chirico-Post, J; Benson, F

    1977-07-01

    Unilateral asterixis due to a focal brain lesion is a rare occurrence. Acute asterixis restricted to the left upper extremity appeared in a patient in association with signs of acute midbrain dysfunction, without changes in mental status or in the EEG, and in the absence of metabolic or toxic disturbance. Electromyography disclosed features typical of asterixis due to metabolic causes.

  2. Injectable tissue-engineered soft tissue for tissue augmentation.

    PubMed

    Rhee, Sung-Mi; You, Hi-Jin; Han, Seung-Kyu

    2014-11-01

    Soft tissue augmentation is a process of implanting tissues or materials to treat wrinkles or soft tissue defects in the body. Over the years, various materials have evolved to correct soft tissue defects, including a number of tissues and polymers. Autogenous dermis, autogenous fat, autogenous dermis-fat, allogenic dermis, synthetic implants, and fillers have been widely accepted for soft tissue augmentations. Tissue engineering technology has also been introduced and opened a new venue of opportunities in this field. In particular, a long-lasting filler consisting of hyaluronic acid filler and living human mesenchymal cells called "injectable tissue-engineered soft tissue" has been created and applied clinically, as this strategy has many advantages over conventional methods. Fibroblasts and adipose-derived stromal vascular fraction cells can be clinically used as injectable tissue-engineered soft tissue at present. In this review, information on the soft tissue augmentation method using the injectable tissue-engineered soft tissue is provided.

  3. Tissue irradiator

    DOEpatents

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-12-16

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in- vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood- carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170.

  4. Photochemical tissue bonding

    DOEpatents

    Redmond, Robert W.; Kochevar, Irene E.

    2012-01-10

    Photochemical tissue bonding methods include the application of a photosensitizer to a tissue and/or tissue graft, followed by irradiation with electromagnetic energy to produce a tissue seal. The methods are useful for tissue adhesion, such as in wound closure, tissue grafting, skin grafting, musculoskeletal tissue repair, ligament or tendon repair and corneal repair.

  5. Tissue Photolithography

    NASA Technical Reports Server (NTRS)

    Wade, Lawrence A.; Kartalov, Emil; Shibata, Darryl; Taylor, Clive

    2011-01-01

    Tissue lithography will enable physicians and researchers to obtain macromolecules with high purity (greater than 90 percent) from desired cells in conventionally processed, clinical tissues by simply annotating the desired cells on a computer screen. After identifying the desired cells, a suitable lithography mask will be generated to protect the contents of the desired cells while allowing destruction of all undesired cells by irradiation with ultraviolet light. The DNA from the protected cells can be used in a number of downstream applications including DNA sequencing. The purity (i.e., macromolecules isolated form specific cell types) of such specimens will greatly enhance the value and information of downstream applications. In this method, the specific cells are isolated on a microscope slide using photolithography, which will be faster, more specific, and less expensive than current methods. It relies on the fact that many biological molecules such as DNA are photosensitive and can be destroyed by ultraviolet irradiation. Therefore, it is possible to protect the contents of desired cells, yet destroy undesired cells. This approach leverages the technologies of the microelectronics industry, which can make features smaller than 1 micrometer with photolithography. A variety of ways has been created to achieve identification of the desired cell, and also to designate the other cells for destruction. This can be accomplished through chrome masks, direct laser writing, and also active masking using dynamic arrays. Image recognition is envisioned as one method for identifying cell nuclei and cell membranes. The pathologist can identify the cells of interest using a microscopic computerized image of the slide, and appropriate custom software. In one of the approaches described in this work, the software converts the selection into a digital mask that can be fed into a direct laser writer, e.g. the Heidelberg DWL66. Such a machine uses a metalized glass plate (with

  6. Undifferentiated Connective Tissue Disease

    MedlinePlus

    ... Home Conditions Undifferentiated Connective Tissue Disease (UCTD) Undifferentiated Connective Tissue Disease (UCTD) Make an Appointment Find a Doctor ... L. Goldstein, MD, MMSc (February 01, 2016) Undifferentiated connective tissue disease (UCTD) is a systemic autoimmune disease. This ...

  7. Necrotizing soft tissue infection

    MedlinePlus

    Necrotizing fasciitis; Fasciitis - necrotizing; Flesh-eating bacteria; Soft tissue gangrene; Gangrene - soft tissue ... Many different types of bacteria can cause this infection. A very severe and usually deadly form of necrotizing soft tissue infection is due to the ...

  8. Tissue bionics: examples in biomimetic tissue engineering.

    PubMed

    Green, David W

    2008-09-01

    Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic.

  9. Adaptability of free-floating green tide algae in the Yellow Sea to variable temperature and light intensity.

    PubMed

    Cui, Jianjun; Zhang, Jianheng; Huo, Yuanzi; Zhou, Lingjie; Wu, Qing; Chen, Liping; Yu, Kefeng; He, Peimin

    2015-12-30

    In this study, the influence of temperature and light intensity on the growth of seedlings and adults of four species of green tide algae (Ulvaprolifera, Ulvacompressa, Ulva flexuosa and Ulvalinza) from the Yellow Sea was evaluated. The results indicated that the specific growth rate (SGR) of seedlings was much higher than that of adults for the four species. The adaptability of U. prolifera is much wider: Adult daily SGRs were the highest among the four species at 15-20 °C with 10-600 μmol · m(-2) · s(-1) and 25-30 °C with 200-600 μmol · m(-2) · s(-1). SGRs were 1.5-3.5 times greater than the other three species at 15-25 °C with 200-600 μmol · m(-2) · s(-1). These results indicate that U. prolifera has better tolerance to high temperature and light intensity than the other three species, which may in part explain why only U. prolifera undergoes large-scale outbreaks and floats to the Qingdao coast while the other three species decline and disappear at the early stage of blooming.

  10. Acute free-floating carotid artery thrombus causing stroke in a young patient: unique etiology and management using endovascular approach.

    PubMed

    Tan, Ai Peng; Taneja, Manish; Seah, Boon Heng; Leong, Hoe Nam; Venketasubramanian, Narayanaswamy

    2014-01-01

    Atherosclerotic disease accounts for 20%-30% of strokes in the general population. In young adults, it is an unexpected event and its causes involve diverse pathologies. Herein, we describe a unique case of acute embolic stroke in a young adult patient due to the presence of a large clot in the right common and internal carotid arteries, as a result of an extrinsic cause. Surgical clot retrieval was considered unsafe at that point in time in view of the active inflammatory changes surrounding the affected vessels. This was eventually treated with a novel endovascular technique, a unique alternative to open surgery, with excellent clinical outcome. To our knowledge, the penumbra system has never been used for thrombus removal in a nonacute setting. PMID:25440371

  11. Tissue oxygen measurement system

    NASA Technical Reports Server (NTRS)

    Soller, Babs R. (Inventor)

    2004-01-01

    A device and method in accordance with the invention for determining the oxygen partial pressure (PO.sub.2) of a tissue by irradiating the tissue with optical radiation such that the light is emitted from the tissue, and by collecting the reflected or transmitted light from the tissue to form an optical spectrum. A spectral processor determines the PO.sub.2 level in tissue by processing this spectrum with a previously-constructed spectral calibration model. The tissue may, for example, be disposed underneath a covering tissue, such as skin, of a patient, and the tissue illuminated and light collected through the skin. Alternatively, direct tissue illumination and collection may be effected with a hand-held or endoscopic probe. A preferred system also determines pH from the same spectrum, and the processor may determine critical conditions and issue warnings based on parameter values.

  12. Engineering complex tissues.

    PubMed

    Atala, Anthony; Kasper, F Kurtis; Mikos, Antonios G

    2012-11-14

    Tissue engineering has emerged at the intersection of numerous disciplines to meet a global clinical need for technologies to promote the regeneration of functional living tissues and organs. The complexity of many tissues and organs, coupled with confounding factors that may be associated with the injury or disease underlying the need for repair, is a challenge to traditional engineering approaches. Biomaterials, cells, and other factors are needed to design these constructs, but not all tissues are created equal. Flat tissues (skin); tubular structures (urethra); hollow, nontubular, viscus organs (vagina); and complex solid organs (liver) all present unique challenges in tissue engineering. This review highlights advances in tissue engineering technologies to enable regeneration of complex tissues and organs and to discuss how such innovative, engineered tissues can affect the clinic.

  13. Tissue engineering in urology.

    PubMed

    Gustafson, C J; Kratz, G

    2001-05-01

    Techniques that are aimed at regeneration of human tissues and organs (tissue engineering) have recently entered into clinical practice. Tissue engineering is currently among the fastest growing areas in medicine, and involves the application of the principles of biology and engineering to the development of functional substitutes for damaged tissues. One of the main limitations of reconstructive surgery in the genitourinary tract is the lack of autologous tissue. This could be changed by the ability to cultivate the patient's own tissues in vitro, or by stimulating the cells in vivo into regeneration of new tissues. The present review discusses how tissue engineering can be used to regenerate some of the tissues of the genitourinary tract. Even though these methods have only recently been introduced clinically into genitourinary medicine, numerous scientific studies have been reported that indicate that these techniques may be of great importance in the near future.

  14. Measuring tissue oxygenation

    NASA Technical Reports Server (NTRS)

    Soyemi, Olusola O. (Inventor); Soller, Babs R. (Inventor); Yang, Ye (Inventor)

    2009-01-01

    Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.

  15. Advancing cardiovascular tissue engineering

    PubMed Central

    Truskey, George A.

    2016-01-01

    Cardiovascular tissue engineering offers the promise of biologically based repair of injured and damaged blood vessels, valves, and cardiac tissue. Major advances in cardiovascular tissue engineering over the past few years involve improved methods to promote the establishment and differentiation of induced pluripotent stem cells (iPSCs), scaffolds from decellularized tissue that may produce more highly differentiated tissues and advance clinical translation, improved methods to promote vascularization, and novel in vitro microphysiological systems to model normal and diseased tissue function. iPSC technology holds great promise, but robust methods are needed to further promote differentiation. Differentiation can be further enhanced with chemical, electrical, or mechanical stimuli. PMID:27303643

  16. Connective Tissue Disorders

    MedlinePlus

    Connective tissue is the material inside your body that supports many of its parts. It is the "cellular ... their work. Cartilage and fat are examples of connective tissue. There are over 200 disorders that impact connective ...

  17. Tissue identification by ultrasound

    NASA Technical Reports Server (NTRS)

    Lecroissette, D. H.; Heyser, R. C.; Gammell, P. M.; Wilson, R. L.

    1978-01-01

    The ultrasonic properties of animal and human soft tissue were measured over the frequency range of 1.5 to 10.0 MHz. The method employed a swept-frequency, coherent technique known as time delay spectrometry. Measurements of attenuation versus frequency on liver, backfat, kidney, pancreas, spleen, breast, and other tissue were made. Considerable attention was paid to tissue handling and in determining the effects of fixing on the attenuation of ultrasound in the tissue.

  18. Development of tissue bank

    PubMed Central

    Narayan, R. P.

    2012-01-01

    The history of tissue banking is as old as the use of skin grafting for resurfacing of burn wounds. Beneficial effects of tissue grafts led to wide spread use of auto and allograft for management of varied clinical conditions like skin wounds, bone defects following trauma or tumor ablation. Availability of adequate amount of tissues at the time of requirement was the biggest challenge that forced clinicians to find out techniques to preserve the living tissue for prolonged period of time for later use and thus the foundation of tissue banking was started in early twentieth century. Harvesting, processing, storage and transportation of human tissues for clinical use is the major activity of tissue banks. Low temperature storage of processed tissue is the best preservation technique at present. Tissue banking organization is a very complex system and needs high technical expertise and skilled personnel for proper functioning in a dedicated facility. A small lapse/deviation from the established protocol leads to loss of precious tissues and or harm to recipients as well as the risk of transmission of deadly diseases and tumors. Strict tissue transplant acts and stringent regulations help to streamline the whole process of tissue banking safe for recipients and to community as whole. PMID:23162240

  19. Tissue engineering of reproductive tissues and organs.

    PubMed

    Atala, Anthony

    2012-07-01

    Regenerative medicine and tissue engineering technology may soon offer new hope for patients with serious injuries and end-stage reproductive organ failure. Scientists are now applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that can restore and maintain normal function in diseased and injured reproductive tissues. In addition, the stem cell field is advancing, and new discoveries in this field will lead to new therapeutic strategies. For example, newly discovered types of stem cells have been retrieved from uterine tissues such as amniotic fluid and placental stem cells. The process of therapeutic cloning and the creation of induced pluripotent cells provide still other potential sources of stem cells for cell-based tissue engineering applications. Although stem cells are still in the research phase, some therapies arising from tissue engineering endeavors that make use of autologous adult cells have already entered the clinic. This article discusses these tissue engineering strategies for various organs in the male and female reproductive tract.

  20. Mechanics of tissue compaction.

    PubMed

    Turlier, Hervé; Maître, Jean-Léon

    2015-12-01

    During embryonic development, tissues deform by a succession and combination of morphogenetic processes. Tissue compaction is the morphogenetic process by which a tissue adopts a tighter structure. Recent studies characterized the respective roles of cells' adhesive and contractile properties in tissue compaction. In this review, we formalize the mechanical and molecular principles of tissue compaction and we analyze through the prism of this framework several morphogenetic events: the compaction of the early mouse embryo, the formation of the fly retina, the segmentation of somites and the separation of germ layers during gastrulation.

  1. Adipose tissue angiogenesis assay.

    PubMed

    Rojas-Rodriguez, Raziel; Gealekman, Olga; Kruse, Maxwell E; Rosenthal, Brittany; Rao, Kishore; Min, Soyun; Bellve, Karl D; Lifshitz, Lawrence M; Corvera, Silvia

    2014-01-01

    Changes in adipose tissue mass must be accompanied by parallel changes in microcirculation. Investigating the mechanisms that regulate adipose tissue angiogenesis could lead to better understanding of adipose tissue function and reveal new potential therapeutic strategies. Angiogenesis is defined as the formation of new capillaries from existing microvessels. This process can be recapitulated in vitro, by incubation of tissue in extracellular matrix components in the presence of pro-angiogenic factors. Here, we describe a method to study angiogenesis from adipose tissue fragments obtained from mouse and human tissue. This assay can be used to define effects of diverse factors added in vitro, as well as the role of endogenously produced factors on angiogenesis. We also describe approaches to quantify angiogenic potential for the purpose of enabling comparisons between subjects, thus providing information on the role of physiological conditions of the donor on adipose tissue angiogenic potential.

  2. Engineering Complex Tissues

    PubMed Central

    MIKOS, ANTONIOS G.; HERRING, SUSAN W.; OCHAREON, PANNEE; ELISSEEFF, JENNIFER; LU, HELEN H.; KANDEL, RITA; SCHOEN, FREDERICK J.; TONER, MEHMET; MOONEY, DAVID; ATALA, ANTHONY; VAN DYKE, MARK E.; KAPLAN, DAVID; VUNJAK-NOVAKOVIC, GORDANA

    2010-01-01

    This article summarizes the views expressed at the third session of the workshop “Tissue Engineering—The Next Generation,” which was devoted to the engineering of complex tissue structures. Antonios Mikos described the engineering of complex oral and craniofacial tissues as a “guided interplay” between biomaterial scaffolds, growth factors, and local cell populations toward the restoration of the original architecture and function of complex tissues. Susan Herring, reviewing osteogenesis and vasculogenesis, explained that the vascular arrangement precedes and dictates the architecture of the new bone, and proposed that engineering of osseous tissues might benefit from preconstruction of an appropriate vasculature. Jennifer Elisseeff explored the formation of complex tissue structures based on the example of stratified cartilage engineered using stem cells and hydrogels. Helen Lu discussed engineering of tissue interfaces, a problem critical for biological fixation of tendons and ligaments, and the development of a new generation of fixation devices. Rita Kandel discussed the challenges related to the re-creation of the cartilage-bone interface, in the context of tissue engineered joint repair. Frederick Schoen emphasized, in the context of heart valve engineering, the need for including the requirements derived from “adult biology” of tissue remodeling and establishing reliable early predictors of success or failure of tissue engineered implants. Mehmet Toner presented a review of biopreservation techniques and stressed that a new breakthrough in this field may be necessary to meet all the needs of tissue engineering. David Mooney described systems providing temporal and spatial regulation of growth factor availability, which may find utility in virtually all tissue engineering and regeneration applications, including directed in vitro and in vivo vascularization of tissues. Anthony Atala offered a clinician’s perspective for functional tissue

  3. Engineering Orthopedic Tissue Interfaces

    PubMed Central

    Yang, Peter J.

    2009-01-01

    While a wide variety of approaches to engineering orthopedic tissues have been proposed, less attention has been paid to the interfaces, the specialized areas that connect two tissues of different biochemical and mechanical properties. The interface tissue plays an important role in transitioning mechanical load between disparate tissues. Thus, the relatively new field of interfacial tissue engineering presents new challenges—to not only consider the regeneration of individual orthopedic tissues, but also to design the biochemical and cellular composition of the linking tissue. Approaches to interfacial tissue engineering may be distinguished based on if the goal is to recreate the interface itself, or generate an entire integrated tissue unit (such as an osteochondral plug). As background for future efforts in engineering orthopedic interfaces, a brief review of the biology and mechanics of each interface (cartilage–bone, ligament–bone, meniscus–bone, and muscle–tendon) is presented, followed by an overview of the state-of-the-art in engineering each tissue, including advances and challenges specific to regenerating the interfaces. PMID:19231983

  4. [Connective tissue dysplasia].

    PubMed

    Piantkovskiĭ, A S

    2012-01-01

    The article presents a diagnosis of dysplasia of connective tissue in athletes, where the most important are the methods of clinical assessment using diagnostic tests and rating scales manifestation of connective tissue dysplasia. Evaluation of patients with suspected connective tissue dysplasia should include inspection of an ophthalmologist, orthopedic trauma, cardiology. Should also be carried out by criteria diagnosis degree of connective tissue dysplasia by T. Y. Smolnova (2003) (Large and small diagnostic criteria), which include: increased skin extensibility, joint hypermobility (sprain, dislocation and subluxation, flat feet), muscle hypotonia, a hereditary predisposition to the disease, evaluation of signs joint hypermobility (Beighton criteria). If during routine medical examination revealed athletes with manifestations of connective tissue dysplasia, they are subject to a more in-depth examination and observation. Early diagnosis of connective tissue dysplasia allows not only to plan the training process, but also reduces the trauma of athletes.

  5. Tissue-resident macrophages

    PubMed Central

    Davies, Luke C.; Jenkins, Stephen J.; Allen, Judith E.; Taylor, Philip R.

    2014-01-01

    Tissue-resident macrophages are a heterogeneous population of immune cells that fulfill tissue-specific and niche-specific functions. These range from dedicated homeostatic functions, such as clearance of cellular debris and iron processing, to central roles in tissue immune-surveillance, response to infection and the resolution of inflammation. Recent studies highlight marked heterogeneity in the origins of tissue macrophages that arise from hematopoietic versus self-renewing embryo-derived populations. We discuss the tissue–niche-specific factors that dictate cell phenotype, the definition of which will allow novel strategies to promote the restoration of tissue homeostasis. Understanding the mechanisms that dictate tissue macrophage heterogeneity should explain why simplified paradigms of macrophage activation do not explain the extent of heterogeneity seen in vivo. PMID:24048120

  6. Biomaterials for Tissue Engineering

    PubMed Central

    Lee, Esther J.; Kasper, F. Kurtis; Mikos, Antonios G.

    2013-01-01

    Biomaterials serve as an integral component of tissue engineering. They are designed to provide architectural framework reminiscent of native extracellular matrix in order to encourage cell growth and eventual tissue regeneration. Bone and cartilage represent two distinct tissues with varying compositional and mechanical properties. Despite these differences, both meet at the osteochondral interface. This article presents an overview of current biomaterials employed in bone and cartilage applications, discusses some design considerations, and alludes to future prospects within this field of research. PMID:23820768

  7. Clarifying Tissue Clearing

    PubMed Central

    Richardson, Douglas S.; Lichtman, Jeff W.

    2015-01-01

    Summary Biological specimens are intrinsically three dimensional; however because of the obscuring effects of light scatter, imaging deep into a tissue volume is problematic. Although efforts to eliminate the scatter by “clearing” the tissue have been ongoing for over a century, there have been a large number of recent innovations. This review introduces the physical basis for light-scatter in tissue, describes the mechanisms underlying various clearing techniques, and discusses several of the major advances in light microscopy for imaging cleared tissue. PMID:26186186

  8. Pulsed Laser Tissue Interaction

    NASA Astrophysics Data System (ADS)

    Walsh, Joseph T.; van Leeuwen, Ton G.; Jansen, E. Duco; Motamedi, Massoud; Welch, Ashley J.

    Pulsed lasers, by virtue of their ability to deliver energy in a spatially and temporally confined fashion, are able to micromachine biological tissues. The clinical success of pulsed laser treatment, however, is often limited by the extent of damage that is caused to the tissue in the vicinity of the ablation crater. In general, pulsed ablation is a trade off between thermal damage to surrounding tissue, caused by relatively long pulses (>100 ms), and mechanical damage to surrounding tissue, caused by relatively short pulses (<1 ms). To identify the origin of pulsed laser induced damage, the possible laser tissue interactions and ablation are discussed here and in Chapter 14. The purpose of this chapter is to provide the reader with a condensed overview of the parameters that must be considered in the process of pulsed laser ablation of soft tissue. In this chapter, pulsed infrared ablation of biological soft tissue is used as a paradigm to illustrate the concepts and design considerations. Generally speaking, the absorption of laser light may lead to photothermal, photomechanical or photochemical interaction with the irradiated tissue [1-5]. The vast majority of therapeutic laser-tissue interactions is based on photothermal interactions where laser energy is converted into heat. Subsequent to thermalization of the absorbed optical energy, heat transfer mechanisms, in particular conduction allow thermal diffusion from high temperature areas to surrounding regions. When laser penetration depth is less than the laser spot radius, the thermal diffusion time, τ th, can be defined as:

  9. Bioreactors for tissue engineering.

    PubMed

    Chen, Huang-Chi; Hu, Yu-Chen

    2006-09-01

    Bioreactors are essential in tissue engineering, not only because they provide an in vitro environment mimicking in vivo conditions for the growth of tissue substitutes, but also because they enable systematic studies of the responses of living tissues to various mechanical and biochemical cues. The basic principles of bioreactor design are reviewed, the bioreactors commonly used for the tissue engineering of cartilage, bone and cardiovascular systems are assessed in terms of their performance and usefulness. Several novel bioreactor types are also reviewed. PMID:16955350

  10. '2' much mitral tissue.

    PubMed

    Barriales-Villa, Roberto; Pérez-Martínez, Fernando; Alvarez-Juárez, Ana I; Vázquez-Rey, Eugenia; Castro-Beiras, Alfonso

    2010-03-01

    A 73-year-old female patient was referred for evaluation after suffering an atypical chest pain. Physical examination and ECG were normal. The echocardiogram showed a normal ventricular function. Attached to the anterior leaflet an accessory mitral valve tissue was identified. In systole, this mitral tissue creates an image that looks like the 'number 2'.

  11. Necrotizing soft tissue infections

    PubMed Central

    Urschel, J.

    1999-01-01

    Necrotizing soft tissue infections are a group of highly lethal infections that typically occur after trauma or surgery. Many individual infectious entities have been described, but they all have similar pathophysiologies, clinical features, and treatment approaches. The essentials of successful treatment include early diagnosis, aggressive surgical debridement, antibiotics, and supportive intensive treatment unit care. The two commonest pitfalls in management are failure of early diagnosis and inadequate surgical debridement. These life-threatening infections are often mistaken for cellulitis or innocent wound infections, and this is responsible for diagnostic delay. Tissue gas is not a universal finding in necrotizing soft tissue infections. This misconception also contributes to diagnostic errors. Incision and drainage is an inappropriate surgical strategy for necrotizing soft tissue infections; excisional debridement is needed. Hyperbaric oxygen therapy may be useful, but it is not as important as aggressive surgical therapy. Despite advances in antibiotic therapy and intensive treatment unit medicine, the mortality of necrotizing soft tissue infections is still high. This article emphasizes common treatment principles for all of these infections, and reviews some of the more important individual necrotizing soft tissue infectious entities.


Keywords: fasciitis; gas gangrene; clostridium infections; streptococcal infections; necrosis; debridement; surgical infections; soft tissue infections PMID:10621873

  12. Engrailed Homeoprotein Protects Mesencephalic Dopaminergic Neurons from Oxidative Stress

    PubMed Central

    Rekaik, Hocine; Blaudin de Thé, François-Xavier; Fuchs, Julia; Massiani-Beaudoin, Olivia; Prochiantz, Alain; Joshi, Rajiv L.

    2016-01-01

    Summary Engrailed homeoproteins are expressed in adult dopaminergic neurons of the substantia nigra. In Engrailed1 heterozygous mice, these neurons start dying at 6 weeks, are more sensitive to oxidative stress, and progressively develop traits similar to those observed following an acute and strong oxidative stress inflected to wild-type neurons. These changes include DNA strand breaks and the modification (intensity and distribution) of several nuclear and nucleolar heterochromatin marks. Engrailed1 and Engrailed2 are biochemically equivalent transducing proteins previously used to antagonize dopaminergic neuron death in Engrailed1 heterozygous mice and in mouse models of Parkinson disease. Accordingly, we show that, following an acute oxidative stress, a single Engrailed2 injection restores all nuclear and nucleolar heterochromatin marks, decreases the number of DNA strand breaks, and protects dopaminergic neurons against apoptosis. PMID:26411690

  13. Mesencephalic stimulation elicits inhibition of phrenic nerve activity in cat.

    PubMed

    Gallman, E A; Lawing, W L; Millhorn, D E

    1991-05-01

    1. Previous work from this laboratory has indicated that the mesencephalon is the anatomical substrate for a mechanism capable of inhibiting central respiratory drive in glomectomized cats for periods of up to 1 h or more following brief exposure to systemic hypoxia; phrenic nerve activity was used as an index of central respiratory drive. 2. The present study was undertaken to further localize the region responsible for the observed post-hypoxic inhibition of respiratory drive. We studied the phrenic nerve response to stimulations of the mesencephalon in anaesthetized, paralysed peripherally chemo-denervated cats with end-expired PCO2 and body temperature servo-controlled. 3. Stimulations of two types were employed. Electrical stimulation allowed rapid determination of sites from which phrenic inhibition could be elicited. Microinjections of excitatory amino acids were used subsequently in order to confine excitation to neuronal cell bodies and not axons of passage. 4. Stimulation of discrete regions of the ventromedial aspect of the mesencephalon in the vicinity of the red nucleus produced substantial inhibition of phrenic activity which lasted up to 45 min. Stimulation of other areas of the mesencephalon either produced no phrenic inhibition or resulted in a slight stimulation of phrenic activity. 5. The results are discussed in the context of the central respiratory response to hypoxia. PMID:1676420

  14. Subependymal glioneuronal hamartoma in the mesencephalic aqueduct of a giraffe.

    PubMed

    Koehler, Jennifer; Cox, Nancy; Passler, Thomas; Wolfe, Dwight

    2012-09-01

    A 1-day-old male giraffe calf (Giraffa camelopardalis) was submitted for necropsy examination after sustaining postnatal head trauma from the cow. In addition to the expected findings of severe cerebral edema and epidural and subarachnoid hemorrhage, there also was present an incidental finding of a subependymal glioneuronal aqueductal hamartoma. Reports of this type of congenital lesion are rare in the human literature, and the lesion has not, to the authors' knowledge, previously been reported in this or any other veterinary species. PMID:23082530

  15. Functional cardiac tissue engineering

    PubMed Central

    Liau, Brian; Zhang, Donghui; Bursac, Nenad

    2013-01-01

    Heart attack remains the leading cause of death in both men and women worldwide. Stem cell-based therapies, including the use of engineered cardiac tissues, have the potential to treat the massive cell loss and pathological remodeling resulting from heart attack. Specifically, embryonic and induced pluripotent stem cells are a promising source for generation of therapeutically relevant numbers of functional cardiomyocytes and engineering of cardiac tissues in vitro. This review will describe methodologies for successful differentiation of pluripotent stem cells towards the cardiovascular cell lineages as they pertain to the field of cardiac tissue engineering. The emphasis will be placed on comparing the functional maturation in engineered cardiac tissues and developing heart and on methods to quantify cardiac electrical and mechanical function at different spatial scales. PMID:22397609

  16. Tissue engineering: orthopedic applications.

    PubMed

    Laurencin, C T; Ambrosio, A M; Borden, M D; Cooper, J A

    1999-01-01

    Because of an aging population and increased occurrence of sports-related injuries, musculoskeletal disorders have become one of the major health concerns in the United States. Current treatments, although fairly successful, do not provide the optimum therapy. These treatments typically rely on donor tissues obtained either from the patient or from another source. The former raises the issue of supply, whereas the latter poses the risk of rejection and disease transfer. This has prompted orthopedic surgeons and scientists to look for viable alternatives. In recent years, tissue engineering has gained increasing support as a method to treat orthopedic disorders. Because it uses principles of engineering, biology, and chemistry, tissue engineering may provide a more effective approach to the treatment of musculoskeletal disorders than traditional methods. This chapter presents a review of current methods and new tissue-engineering techniques for the treatment of disorders affecting bone, ligament, and cartilage.

  17. Spectromicroscopy of Brain Tissue

    NASA Astrophysics Data System (ADS)

    Frazer, Bradley; Cannara, Rachel; Gilbert, Benjamin; Destasio, Gelsomina; Ogg, Mandy; Gough, Kathy

    2001-03-01

    X-ray PhotoElectron Emission Microscopy (X-PEEM) was originally developed for studying the surface microchemistry of materials science specimens. It has then evolved into a valuable tool to investigate the magnetic properties of materials and the microchemistry of cells and tissues. We used the MEPHISTO X-PEEM instrument, installed at the UW-Synchrotron Radiation Center to detect trace concentrations of non-physiological elements in senile brain tissue specimens. These tissues contain a large number of plaques, in which all the compounds and elements that the brain does not need are disposed and stored. We hypothesized that plaques should contain elements, such as Si, B, and Al which are very abundant on the Earth crust but absent from healthy tissues. We verified this hypothesis with MEPHISTO and found evidence of Si and B, and suspect Al. We also found a higher than normal concentration of Fe.

  18. Facial Soft Tissue Trauma

    PubMed Central

    Kretlow, James D.; McKnight, Aisha J.; Izaddoost, Shayan A.

    2010-01-01

    Traumatic facial soft tissue injuries are commonly encountered in the emergency department by plastic surgeons and other providers. Although rarely life-threatening, the treatment of these injuries can be complex and may have significant impact on the patient's facial function and aesthetics. This article provides a review of the relevant literature related to this topic and describes the authors' approach to the evaluation and management of the patient with facial soft tissue injuries. PMID:22550459

  19. Tissue Culture in Microgravity

    NASA Technical Reports Server (NTRS)

    Pellis, Neal R.; Duray, Paul H.; Hatfill, Steven J.

    1997-01-01

    Attempts to simulate normal tissue micro-environments in vitro have been thwarted by the complexity and plasticity of the extracellular matrix, which is important in regulating cytoskeletal and nuclear matrix proteins. Gravity is one of the problems, tending to separate components that should be kept together. For space shuttle experiments, NASA engineers devised a double-walled rotating bioreactor, which is proving to be a useful tissue culture device on earth as well as in space.

  20. Engineering graded tissue interfaces.

    PubMed

    Phillips, Jennifer E; Burns, Kellie L; Le Doux, Joseph M; Guldberg, Robert E; García, Andrés J

    2008-08-26

    Interfacial zones between tissues provide specialized, transitional junctions central to normal tissue function. Regenerative medicine strategies focused on multiple cell types and/or bi/tri-layered scaffolds do not provide continuously graded interfaces, severely limiting the integration and biological performance of engineered tissue substitutes. Inspired by the bone-soft tissue interface, we describe a biomaterial-mediated gene transfer strategy for spatially regulated genetic modification and differentiation of primary dermal fibroblasts within tissue-engineered constructs. We demonstrate that zonal organization of osteoblastic and fibroblastic cellular phenotypes can be engineered by a simple, one-step seeding of fibroblasts onto scaffolds containing a spatial distribution of retrovirus encoding the osteogenic transcription factor Runx2/Cbfa1. Gradients of immobilized retrovirus, achieved via deposition of controlled poly(L-lysine) densities, resulted in spatial patterns of transcription factor expression, osteoblastic differentiation, and mineralized matrix deposition. Notably, this graded distribution of mineral deposition and mechanical properties was maintained when implanted in vivo in an ectopic site. Development of this facile and robust strategy is significant toward the regeneration of continuous interfacial zones that mimic the cellular and microstructural characteristics of native tissue.

  1. Optical birefringence of aorta tissues

    NASA Astrophysics Data System (ADS)

    Tang, G. C.; Wang, W. B.; Pu, Y.; Alfano, R. R.

    2010-02-01

    The optical birefringence of porcine aortic tissues including heated and non-heated tissues was studied using polarization technique. The measurements show that a whole piece of aortic tissue has birefringence properties like a uniaxial crystal. The experiment results indicate that the birefringence status of tissue have a potential application for monitoring changes of tissue structure due to burning, plastic surgery, laser tissue welding and wound healing.

  2. The tissue diagnostic instrument.

    PubMed

    Hansma, Paul; Yu, Hongmei; Schultz, David; Rodriguez, Azucena; Yurtsev, Eugene A; Orr, Jessica; Tang, Simon; Miller, Jon; Wallace, Joseph; Zok, Frank; Li, Cheng; Souza, Richard; Proctor, Alexander; Brimer, Davis; Nogues-Solan, Xavier; Mellbovsky, Leonardo; Peña, M Jesus; Diez-Ferrer, Oriol; Mathews, Phillip; Randall, Connor; Kuo, Alfred; Chen, Carol; Peters, Mathilde; Kohn, David; Buckley, Jenni; Li, Xiaojuan; Pruitt, Lisa; Diez-Perez, Adolfo; Alliston, Tamara; Weaver, Valerie; Lotz, Jeffrey

    2009-05-01

    Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument (TDI), a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection.

  3. [Connective tissue and inflammation].

    PubMed

    Jakab, Lajos

    2014-03-23

    The author summarizes the structure of the connective tissues, the increasing motion of the constituents, which determine the role in establishing the structure and function of that. The structure and function of the connective tissue are related to each other in the resting as well as inflammatory states. It is emphasized that cellular events in the connective tissue are part of the defence of the organism, the localisation of the damage and, if possible, the maintenance of restitutio ad integrum. The organism responds to damage with inflammation, the non specific immune response, as well as specific, adaptive immunity. These processes are located in the connective tissue. Sterile and pathogenic inflammation are relatively similar processes, but inevitable differences are present, too. Sialic acids and glycoproteins containing sialic acids have important roles, and the role of Siglecs is also highlighted. Also, similarities and differences in damages caused by pathogens and sterile agents are briefly summarized. In addition, the roles of adhesion molecules linked to each other, and the whole event of inflammatory processes are presented. When considering practical consequences it is stressed that the structure (building up) of the organism and the defending function of inflammation both have fundamental importance. Inflammation has a crucial role in maintaining the integrity and the unimpaired somato-psychological state of the organism. Thus, inflammation serves as a tool of organism identical with the natural immune response, inseparably connected with the specific, adaptive immune response. The main events of the inflammatory processes take place in the connective tissue.

  4. The tissue diagnostic instrument

    PubMed Central

    Hansma, Paul; Yu, Hongmei; Schultz, David; Rodriguez, Azucena; Yurtsev, Eugene A.; Orr, Jessica; Tang, Simon; Miller, Jon; Wallace, Joseph; Zok, Frank; Li, Cheng; Souza, Richard; Proctor, Alexander; Brimer, Davis; Nogues-Solan, Xavier; Mellbovsky, Leonardo; Peña, M. Jesus; Diez-Ferrer, Oriol; Mathews, Phillip; Randall, Connor; Kuo, Alfred; Chen, Carol; Peters, Mathilde; Kohn, David; Buckley, Jenni; Li, Xiaojuan; Pruitt, Lisa; Diez-Perez, Adolfo; Alliston, Tamara; Weaver, Valerie; Lotz, Jeffrey

    2009-01-01

    Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument (TDI), a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection. PMID:19485522

  5. Mechanobiology of bone tissue.

    PubMed

    Klein-Nulend, J; Bacabac, R G; Mullender, M G

    2005-12-01

    In order to obtain bones that combine a proper resistance against mechanical failure with a minimum use of material, bone mass and its architecture are continuously being adapted to the prevailing mechanical loads. It is currently believed that mechanical adaptation is governed by the osteocytes, which respond to a loading-induced flow of interstitial fluid through the lacuno-canalicular network by producing signaling molecules. An optimal bone architecture and density may thus not only be determined by the intensity and spatial distribution of mechanical stimuli, but also by the mechanoresponsiveness of osteocytes. Bone cells are highly responsive to mechanical stimuli, but the critical components in the load profile are still unclear. Whether different components such as fluid shear, tension or compression may affect cells differently is also not known. Although both tissue strain and fluid shear stress cause cell deformation, these stimuli might excite different signaling pathways related to bone growth and remodeling. In order to define new approaches for bone tissue engineering in which bioartificial organs capable of functional load bearing are created, it is important to use cells responding to the local forces within the tissue, whereby biophysical stimuli need to be optimized to ensure rapid tissue regeneration and strong tissue repair.

  6. The tissue diagnostic instrument

    NASA Astrophysics Data System (ADS)

    Hansma, Paul; Yu, Hongmei; Schultz, David; Rodriguez, Azucena; Yurtsev, Eugene A.; Orr, Jessica; Tang, Simon; Miller, Jon; Wallace, Joseph; Zok, Frank; Li, Cheng; Souza, Richard; Proctor, Alexander; Brimer, Davis; Nogues-Solan, Xavier; Mellbovsky, Leonardo; Peña, M. Jesus; Diez-Ferrer, Oriol; Mathews, Phillip; Randall, Connor; Kuo, Alfred; Chen, Carol; Peters, Mathilde; Kohn, David; Buckley, Jenni; Li, Xiaojuan; Pruitt, Lisa; Diez-Perez, Adolfo; Alliston, Tamara; Weaver, Valerie; Lotz, Jeffrey

    2009-05-01

    Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument (TDI), a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection.

  7. Cerebral and Tissue Oximetry

    PubMed Central

    Steppan, Jochen; Hogue, Charles W.

    2014-01-01

    The use of near-infrared spectroscopy (NIRS) has been increasingly adopted in cardiac surgery to measure regional cerebral oxygen saturation. This method takes advantage of the fact that light in the near-infrared spectrum penetrates tissue, including bone and muscle. Sensors are placed at fixed distances from a light emitter, and algorithms subtract superficial light absorption from deep absorption to provide an index of tissue oxygenation. Although the popularity of NIRS monitoring is growing, definitive data that prove outcome benefits with its use remain sparse. Therefore, widespread, routine use of NIRS as a standard-of-care monitor cannot be recommended at present. Recent investigations have focused on the use of NIRS in subgroups that may benefit from NIRS monitoring, such as pediatric patients. Furthermore, a novel application of processed NIRS information for monitoring cerebral autoregulation and tissue oxygenation (e.g., kidneys and the gut) is promising. PMID:25480772

  8. Tissue-like phantoms

    DOEpatents

    Frangioni, John V.; De Grand, Alec M.

    2007-10-30

    The invention is based, in part, on the discovery that by combining certain components one can generate a tissue-like phantom that mimics any desired tissue, is simple and inexpensive to prepare, and is stable over many weeks or months. In addition, new multi-modal imaging objects (e.g., beads) can be inserted into the phantoms to mimic tissue pathologies, such as cancer, or merely to serve as calibration standards. These objects can be imaged using one, two, or more (e.g., four) different imaging modalities (e.g., x-ray computed tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), and near-infrared (NIR) fluorescence) simultaneously.

  9. Biomechanics of brain tissue.

    PubMed

    Prevost, Thibault P; Balakrishnan, Asha; Suresh, Subra; Socrate, Simona

    2011-01-01

    The dynamic behavior of porcine brain tissue, obtained from a series of in vitro observations and experiments, is analyzed and described here with the aid of a large strain, nonlinear, viscoelastic constitutive model. Mixed gray and white matter samples excised from the superior cortex were tested in unconfined uniaxial compression within 15h post mortem. The test sequence consisted of three successive load-unload segments at strain rates of 1, 0.1 and 0.01 s⁻¹, followed by stress relaxation (n=25). The volumetric compliance of the tissue was assessed for a subset of specimens (n=7) using video extensometry techniques. The tissue response exhibited moderate compressibility, substantial nonlinearity, hysteresis, conditioning and rate dependence. A large strain kinematics nonlinear viscoelastic model was developed to account for the essential features of the tissue response over the entire deformation history. The corresponding material parameters were obtained by fitting the model to the measured conditioned response (axial and volumetric) via a numerical optimization scheme. The model successfully captures the observed complexities of the material response in loading, unloading and relaxation over the entire range of strain rates. The accuracy of the model was further verified by comparing model predictions with the tissue response in unconfined compression at higher strain rate (10 s⁻¹) and with literature data in uniaxial tension. The proposed constitutive framework was also found to be adequate to model the loading response of brain tissue in uniaxial compression over a wider range of strain rates (0.01-3000 s⁻¹), thereby providing a valuable tool for simulations of dynamic transients (impact, blast/shock wave propagation) leading to traumatic brain injury.

  10. Permanent soft tissue fillers.

    PubMed

    Wilson, YuShan L; Ellis, David A F

    2011-12-01

    As our youth-oriented society ages, interest in nonsurgical aesthetic techniques has generated a dramatic rise in the use of filling agents for facial rejuvenation. Backed by multiple published studies documenting safety and efficacy, soft tissue fillers are often viewed as treatments with minimal recovery time and limited risk of complications when compared with traditional surgical interventions. This has led to a genuine demand for fillers with similar safety profiles but ever increasing longevity in their aesthetic corrections. This review addresses many of the permanent soft tissue fillers that are commercially available worldwide as well as important concerns regarding their complications.

  11. Polarized light propagation through tissue and tissue phantoms

    SciTech Connect

    Sankaran, V; Walsh, J T JR; Maitland, D J

    2000-02-08

    We show that standard tissue phantoms can be used to mimic the intensity and polarization properties of tissue. Polarized light propagation through biologic tissue is typically studied using tissue phantoms consisting of dilute aqueous suspensions of microspheres. The dilute phantoms can empirically match tissue polarization and intensity properties. One discrepancy between the dilute phantoms and tissue exist: common tissue phantoms, such as dilute Intralipid and dilute 1-{micro}m-diameter polystyrene microsphere suspensions, depolarize linearly polarized light more quickly than circularly polarized light. In dense tissue, however, where scatterers are often located in close proximity to one another, circularly polarized light is depolarized similar to or more quickly than linearly polarized light. We also demonstrate that polarized light propagates differently in dilute versus densely packed microsphere suspensions, which may account for the differences seen between polarized light propagation in common dilute tissue phantoms versus dense biologic tissue.

  12. Targeting adipose tissue

    PubMed Central

    2012-01-01

    Two different types of adipose tissues can be found in humans enabling them to respond to starvation and cold: white adipose tissue (WAT) is generally known and stores excess energy in the form of triacylglycerol (TG), insulates against cold, and serves as a mechanical cushion. Brown adipose tissue (BAT) helps newborns to cope with cold. BAT has the capacity to uncouple the mitochondrial respiratory chain, thereby generating heat rather than adenosine triphosphate (ATP). The previously widely held view was that BAT disappears rapidly after birth and is no longer present in adult humans. Using positron emission tomography (PET), however, it was recently shown that metabolically active BAT occurs in defined regions and scattered in WAT of the adult and possibly has an influence on whole-body energy homeostasis. In obese individuals adipose tissue is at the center of metabolic syndrome. Targeting of WAT by thiazolidinediones (TZDs), activators of peroxisome proliferator-activated receptor γ (PPARγ) a ‘master’ regulator of fat cell biology, is a current therapy for the treatment of type 2 diabetes. Since its unique capacity to increase energy consumption of the body and to dissipate surplus energy as heat, BAT offers new perspectives as a therapeutic target for the treatment of obesity and associated diseases such as type 2 diabetes and metabolic syndrome. Recent discoveries of new signaling pathways of BAT development give rise to new therapeutic possibilities in order to influence BAT content and activity. PMID:23102228

  13. Eye tissues study

    NASA Astrophysics Data System (ADS)

    Tuchin, Valery V.; Bashkatov, Alexey N.; Maksimova, Irina L.; Sinichkin, Yurii P.; Simonenko, Georgy V.; Genina, Elina A.; Lakodina, Nina A.

    2001-08-01

    Theoretical and in vitro and in vivo experimental study of spectral and polarization characteristics of the human and rabbit eye tissues are presented. The possibility of control of optical properties of eye cornea, lens and sclera is discussed and realized experimentally for glucose solution as the refractive index matching factor.

  14. Tissue non-linearity.

    PubMed

    Duck, F

    2010-01-01

    The propagation of acoustic waves is a fundamentally non-linear process, and only waves with infinitesimally small amplitudes may be described by linear expressions. In practice, all ultrasound propagation is associated with a progressive distortion in the acoustic waveform and the generation of frequency harmonics. At the frequencies and amplitudes used for medical diagnostic scanning, the waveform distortion can result in the formation of acoustic shocks, excess deposition of energy, and acoustic saturation. These effects occur most strongly when ultrasound propagates within liquids with comparatively low acoustic attenuation, such as water, amniotic fluid, or urine. Attenuation by soft tissues limits but does not extinguish these non-linear effects. Harmonics may be used to create tissue harmonic images. These offer improvements over conventional B-mode images in spatial resolution and, more significantly, in the suppression of acoustic clutter and side-lobe artefacts. The quantity B/A has promise as a parameter for tissue characterization, but methods for imaging B/A have shown only limited success. Standard methods for the prediction of tissue in-situ exposure from acoustic measurements in water, whether for regulatory purposes, for safety assessment, or for planning therapeutic regimes, may be in error because of unaccounted non-linear losses. Biological effects mechanisms are altered by finite-amplitude effects. PMID:20349813

  15. Soft tissue augmentation.

    PubMed

    Hirsch, Ranella J; Cohen, Joel L

    2006-09-01

    Recent additions to the soft tissue augmentation armamentarium have greatly increased the dermatologic surgeon's choices in optimizing facial contouring and the treatment of acne scars. In this article, we review the science of fillers and look at the future of dermal fillers.

  16. [Soft-tissue fillers].

    PubMed

    Dallara, J-M

    2008-02-01

    Injections of soft-tissue fillers have rapidly become accessible and essential. When dealing with facial aging, it is logical to compensate for the loss of volume, but the optimisation of a younger face involves a 3D strategy as well.

  17. Hypoelastic Soft Tissues

    PubMed Central

    Freed, Alan D.; Einstein, Daniel R.; Sacks, Michael S.

    2010-01-01

    In Part I, a novel hypoelastic framework for soft-tissues was presented. One of the hallmarks of this new theory is that the well-known exponential behavior of soft-tissues arises consistently and spontaneously from the integration of a rate based formulation. In Part II, we examine the application of this framework to the problem of biaxial kinematics, which are common in experimental soft-tissue characterization. We confine our attention to an isotropic formulation in order to highlight the distinction between non-linearity and anisotropy. In order to provide a sound foundation for the membrane extension of our earlier hypoelastic framework, the kinematics and kinetics of in-plane biaxial extension are revisited, and some enhancements are provided. Specifically, the conventional stress-to-traction mapping for this boundary value problem is shown to violate the conservation of angular momentum. In response, we provide a corrected mapping. In addition, a novel means for applying loads to in-plane biaxial experiments is proposed. An isotropic, isochoric, hypoelastic, constitutive model is applied to an in-plane biaxial experiment done on glutaraldehyde treated bovine pericardium. The experiment is comprised of eight protocols that radially probe the biaxial plane. Considering its simplicity (two adjustable parameters) the model does a reasonably good job of describing the non-linear normal responses observed in these experimental data, which are more prevalent than are the anisotropic responses exhibited by this tissue. PMID:21394222

  18. Sensing in tissue bioreactors

    NASA Astrophysics Data System (ADS)

    Rolfe, P.

    2006-03-01

    Specialized sensing and measurement instruments are under development to aid the controlled culture of cells in bioreactors for the fabrication of biological tissues. Precisely defined physical and chemical conditions are needed for the correct culture of the many cell-tissue types now being studied, including chondrocytes (cartilage), vascular endothelial cells and smooth muscle cells (blood vessels), fibroblasts, hepatocytes (liver) and receptor neurones. Cell and tissue culture processes are dynamic and therefore, optimal control requires monitoring of the key process variables. Chemical and physical sensing is approached in this paper with the aim of enabling automatic optimal control, based on classical cell growth models, to be achieved. Non-invasive sensing is performed via the bioreactor wall, invasive sensing with probes placed inside the cell culture chamber and indirect monitoring using analysis within a shunt or a sampling chamber. Electroanalytical and photonics-based systems are described. Chemical sensing for gases, ions, metabolites, certain hormones and proteins, is under development. Spectroscopic analysis of the culture medium is used for measurement of glucose and for proteins that are markers of cell biosynthetic behaviour. Optical interrogation of cells and tissues is also investigated for structural analysis based on scatter.

  19. Tissue dynamics with permeation.

    PubMed

    Ranft, J; Prost, J; Jülicher, F; Joanny, J-F

    2012-06-01

    Animal tissues are complex assemblies of cells, extracellular matrix (ECM), and permeating interstitial fluid. Whereas key aspects of the multicellular dynamics can be captured by a one-component continuum description, cell division and apoptosis imply material turnover between different components that can lead to additional mechanical conditions on the tissue dynamics. We extend our previous description of tissues in order to account for a cell/ECM phase and the permeating interstitial fluid independently. In line with our earlier work, we consider the cell/ECM phase to behave as an elastic solid in the absence of cell division and apoptosis. In addition, we consider the interstitial fluid as ideal on the relevant length scales, i.e., we ignore viscous stresses in the interstitial fluid. Friction between the fluid and the cell/ECM phase leads to a Darcy-like relation for the interstitial fluid velocity and introduces a new characteristic length scale. We discuss the dynamics of a tissue confined in a chamber with a permeable piston close to the homeostatic state where cell division and apoptosis balance, and we calculate the rescaled effective diffusion coefficient for cells. For different mass densities of the cell/ECM component and the interstitial fluid, a treadmilling steady state due to gravitational forces can be found.

  20. NASA Bioreactor tissue culture

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Dr. Lisa E. Freed of the Massachusetts Institute of Technology and her colleagues have reported that initially disc-like specimens tend to become spherical in space, demonstrating that tissues can grow and differentiate into distinct structures in microgravity. The Mir Increment 3 (Sept. 16, 1996 - Jan. 22, 1997) samples were smaller, more spherical, and mechanically weaker than Earth-grown control samples. These results demonstrate the feasibility of microgravity tissue engineering and may have implications for long human space voyages and for treating musculoskeletal disorders on earth. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

  1. Photoacoustic thermography of tissue.

    PubMed

    Ke, Haixin; Tai, Stephen; Wang, Lihong V

    2014-02-01

    Photoacoustic (PA) techniques can measure temperature in biological tissues because PA signal amplitude is sensitive to tissue temperature. So far, temperature-measuring PA techniques have focused on sensing of temperature changes at a single position. In this work, we photoacoustically measured spatial distribution of temperature in deep tissue. By monitoring the temperature at a single position using a thermocouple, the relationship between the PA signal amplitude and the actual temperature was determined. The relationship was then used to translate a PA image into a temperature map. This study showed that it is possible to calibrate the system for the temperature range of hyperthermia using single-point measurements over a smaller temperature range. Our experimental results showed a precision of -0.8±0.4°C (mean±standard error) in temperature measurement, and a spatial resolution as fine as 1.0 mm. PA techniques can be potentially applied to monitor temperature distribution deep in tissue during hyperthermia treatment of cancer.

  2. Neoproteoglycans in tissue engineering

    PubMed Central

    Weyers, Amanda; Linhardt, Robert J.

    2014-01-01

    Proteoglycans, comprised of a core protein to which glycosaminoglycan chains are covalently linked, are an important structural and functional family of macromolecules found in the extracellular matrix. Advances in our understanding of biological interactions have lead to a greater appreciation for the need to design tissue engineering scaffolds that incorporate mimetics of key extracellular matrix components. A variety of synthetic and semisynthetic molecules and polymers have been examined by tissue engineers that serve as structural, chemical and biological replacements for proteoglycans. These proteoglycan mimetics have been referred to as neoproteoglycans and serve as functional and therapeutic replacements for natural proteoglycans that are often unavailable for tissue engineering studies. Although neoproteoglycans have important limitations, such as limited signaling ability and biocompatibility, they have shown promise in replacing the natural activity of proteoglycans through cell and protein binding interactions. This review focuses on the recent in vivo and in vitro tissue engineering applications of three basic types of neoproteoglycan structures, protein–glycosaminoglycan conjugates, nano-glycosaminoglycan composites and polymer–glycosaminoglycan complexes. PMID:23399318

  3. Plant Tissue Culture Studies.

    ERIC Educational Resources Information Center

    Smith, Robert Alan

    Plant tissue culture has developed into a valid botanical discipline and is considered a key area of biotechnology, but it has not been a key component of the science curriculum because of the expensive and technical nature of research in this area. This manual presents a number of activities that are relatively easy to prepare and perform. The…

  4. Modular Tissue Engineering: Engineering Biological Tissues from the Bottom Up

    PubMed Central

    Nichol, Jason W.; Khademhosseini, Ali

    2009-01-01

    Tissue engineering creates biological tissues that aim to improve the function of diseased or damaged tissues. To enhance the function of engineered tissues there is a need to generate structures that mimic the intricate architecture and complexity of native organs and tissues. With the desire to create more complex tissues with features such as developed and functional microvasculature, cell binding motifs and tissue specific morphology, tissue engineering techniques are beginning to focus on building modular microtissues with repeated functional units. The emerging field known as modular tissue engineering focuses on fabricating tissue building blocks with specific microarchitectural features and using these modular units to engineer biological tissues from the bottom up. In this review we will examine the promise and shortcomings of “bottom-up” approaches to creating engineered biological tissues. Specifically, we will survey the current techniques for controlling cell aggregation, proliferation and extracellular matrix deposition, as well as approaches to generating shape-controlled tissue modules. We will then highlight techniques utilized to create macroscale engineered biological tissues from modular microscale units. PMID:20179781

  5. Biomimetic 3D tissue printing for soft tissue regeneration.

    PubMed

    Pati, Falguni; Ha, Dong-Heon; Jang, Jinah; Han, Hyun Ho; Rhie, Jong-Won; Cho, Dong-Woo

    2015-09-01

    Engineered adipose tissue constructs that are capable of reconstructing soft tissue with adequate volume would be worthwhile in plastic and reconstructive surgery. Tissue printing offers the possibility of fabricating anatomically relevant tissue constructs by delivering suitable matrix materials and living cells. Here, we devise a biomimetic approach for printing adipose tissue constructs employing decellularized adipose tissue (DAT) matrix bioink encapsulating human adipose tissue-derived mesenchymal stem cells (hASCs). We designed and printed precisely-defined and flexible dome-shaped structures with engineered porosity using DAT bioink that facilitated high cell viability over 2 weeks and induced expression of standard adipogenic genes without any supplemented adipogenic factors. The printed DAT constructs expressed adipogenic genes more intensely than did non-printed DAT gel. To evaluate the efficacy of our printed tissue constructs for adipose tissue regeneration, we implanted them subcutaneously in mice. The constructs did not induce chronic inflammation or cytotoxicity postimplantation, but supported positive tissue infiltration, constructive tissue remodeling, and adipose tissue formation. This study demonstrates that direct printing of spatially on-demand customized tissue analogs is a promising approach to soft tissue regeneration.

  6. Modular Tissue Engineering: Engineering Biological Tissues from the Bottom Up.

    PubMed

    Nichol, Jason W; Khademhosseini, Ali

    2009-01-01

    Tissue engineering creates biological tissues that aim to improve the function of diseased or damaged tissues. To enhance the function of engineered tissues there is a need to generate structures that mimic the intricate architecture and complexity of native organs and tissues. With the desire to create more complex tissues with features such as developed and functional microvasculature, cell binding motifs and tissue specific morphology, tissue engineering techniques are beginning to focus on building modular microtissues with repeated functional units. The emerging field known as modular tissue engineering focuses on fabricating tissue building blocks with specific microarchitectural features and using these modular units to engineer biological tissues from the bottom up. In this review we will examine the promise and shortcomings of "bottom-up" approaches to creating engineered biological tissues. Specifically, we will survey the current techniques for controlling cell aggregation, proliferation and extracellular matrix deposition, as well as approaches to generating shape-controlled tissue modules. We will then highlight techniques utilized to create macroscale engineered biological tissues from modular microscale units.

  7. Dinitrotoluene in deer tissues

    SciTech Connect

    Shugart, L.R.

    1991-09-30

    Badger Army Ammunition Plant (BAAP), Baraboo, Wisconsin, has within a security-fenced area, a herd of whitetail deer. The US Army and the State of Wisconsin, Department of Health and Social Services have determined that approximately 20 of the deer be harvested and tissue samples thus collected be analyzed for 2,4- and 2,6-dinitrotoluene (2,4- and 2,6-DNT) by high pressure liquid chromatography (HPLC) to a sensitivity of 0.1 part per million (ppm). The HPLC analyses will be done at the Oak Ridge National Laboratory (ORNL) following protocol used previously for similar work for other government sites. ORNL shall instruct Olin relative to the quantity and type of tissue required, storage and shipment requirements, and other information to ensure that all protocol and chain of custody requirements are clear. A final report will be made to Olin Corporation upon completion of the HPLC analyses.

  8. Genital soft tissue tumors.

    PubMed

    Schoolmeester, John K; Fritchie, Karen J

    2015-07-01

    Mesenchymal neoplasms of the vulvovaginal and inguinoscrotal regions are among the most diagnostically challenging specimens in the pathology laboratory owing largely to their unique intersection between general soft tissue tumors and relatively genital-specific mesenchymal tumors. Genital stromal tumors are a unique subset of soft tissue tumors encountered at this location, and this group includes fibroepithelial stromal polyp, superficial (cervicovaginal) myofibroblastoma, cellular angiofibroma, mammary-type myofibroblastoma, angiomyofibroblastoma and aggressive angiomyxoma. Aside from the striking morphologic and immunophenotypic similarity that is seen with these entities, there is evidence that a subset of genital stromal tumors may be linked genetically. This review will focus on simplifying this group of tumors and provide the pathologist or dermatopathologist with practical management information. Smooth muscle tumors of the external genitalia will also be discussed.

  9. Nicotine and periodontal tissues

    PubMed Central

    Malhotra, Ranjan; Kapoor, Anoop; Grover, Vishakha; Kaushal, Sumit

    2010-01-01

    Tobacco use has been recognized to be a significant risk factor for the development and progression of periodontal disease. Its use is associated with increased pocket depths, loss of periodontal attachment, alveolar bone and a higher rate of tooth loss. Nicotine, a major component and most pharmacologically active agent in tobacco is likely to be a significant contributing factor for the exacerbation of periodontal diseases. Available literature suggests that nicotine affects gingival blood flow, cytokine production, neutrophil and other immune cell function; connective tissue turnover, which can be the possible mechanisms responsible for overall effects of tobacco on periodontal tissues. Inclusion of tobacco cessation as a part of periodontal therapy encourages dental professionals to become more active in tobacco cessation counseling. This will have far reaching positive effects on our patients’ oral and general health. PMID:20922084

  10. Tissue engineering the kidney.

    PubMed

    Hammerman, Marc R

    2003-04-01

    The means by which kidney function can be replaced in humans include dialysis and renal allotransplantation. Dialytic therapies are lifesaving, but often poorly tolerated. Transplantation of human kidneys is limited by the availability of donor organs. During the past decades, a number of different approaches have been applied toward tissue engineering the kidney as a means to replace renal function. The goals of one or another of them included the recapitulation of renal filtration, reabsorptive and secretory functions, and replacement of endocrine/metabolic activities. This review will delineate the progress to date recorded for five approaches: (1) integration of new nephrons into the kidney; (2) growing new kidneys in situ; (3) use of stem cells; (4) generation of histocompatible tissues using nuclear transplantation; and (5) bioengineering of an artificial kidney. All five approaches utilize cellular therapy. The first four employ transplantation as well, and the fifth uses dialysis.

  11. Tissue regeneration with photobiomodulation

    NASA Astrophysics Data System (ADS)

    Tang, Elieza G.; Arany, Praveen R.

    2013-03-01

    Low level light therapy (LLLT) has been widely reported to reduce pain and inflammation and enhance wound healing and tissue regeneration in various settings. LLLT has been noted to have both stimulatory and inhibitory biological effects and these effects have been termed Photobiomodulation (PBM). Several elegant studies have shown the key role of Cytochrome C oxidase and ROS in initiating this process. The downstream biological responses remain to be clearly elucidated. Our work has demonstrated activation of an endogenous latent growth factor complex, TGF-β1, as one of the major biological events in PBM. TGF-β1 has critical roles in various biological processes especially in inflammation, immune responses, wound healing and stem cell biology. This paper overviews some of the studies demonstrating the efficacy of PBM in promoting tissue regeneration.

  12. Tissue expansion in perspective.

    PubMed Central

    Sharpe, D. T.; Burd, R. M.

    1989-01-01

    Tissue expansion is a recent advance in skin cover technique. Its empirical use has enabled many previously difficult reconstructions to be completed without recourse to distant flaps. Its high complication rate and lack of basic scientific understanding at present restrict its use to selected cases, but the quality of repairs possible by this method encourage further serious scientific study. Images fig. 1 fig. 2 fig. 3 fig. 4 fig. 5 PMID:2589784

  13. Tissue blood flow mapping

    NASA Astrophysics Data System (ADS)

    Nilsson, G. E.

    1997-01-01

    The operating principles of Laser Doppler Perfusion Imaging (LDPI) for visualization of the tissue blood perfusion are explained. Using this emerging technology skin perfusion has been investigated in healthy volunteers and in patients with various conditions that affect skin blood flow. LDPI is anticipated to be particularly useful in evaluation of peripheral circulation in diabetics, as an objective tool in irritancy patch testing, assessment of burnt skin and visualization of spot-wise hyperperfusion in breast skin in association with carcinoma.

  14. Reptile Soft Tissue Surgery.

    PubMed

    Di Girolamo, Nicola; Mans, Christoph

    2016-01-01

    The surgical approach to reptiles can be challenging. Reptiles have unique physiologic, anatomic, and pathologic differences. This may result in frustrating surgical experiences. However, recent investigations provided novel, less invasive, surgical techniques. The purpose of this review was to describe the technical aspects behind soft tissue surgical techniques that have been used in reptiles, so as to provide a general guideline for veterinarians working with reptiles.

  15. Lean Tissue Imaging

    PubMed Central

    Heymsfield, Steven B.

    2014-01-01

    Body composition refers to the amount of fat and lean tissues in our body; it is a science that looks beyond a unit of body weight, accounting for the proportion of different tissues and its relationship to health. Although body weight and body mass index are well-known indexes of health status, most researchers agree that they are rather inaccurate measures, especially for elderly individuals and those patients with specific clinical conditions. The emerging use of imaging techniques such as dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and ultrasound imaging in the clinical setting have highlighted the importance of lean soft tissue (LST) as an independent predictor of morbidity and mortality. It is clear from emerging studies that body composition health will be vital in treatment decisions, prognostic outcomes, and quality of life in several nonclinical and clinical states. This review explores the methodologies and the emerging value of imaging techniques in the assessment of body composition, focusing on the value of LST to predict nutrition status. PMID:25239112

  16. Stereolithography in tissue engineering.

    PubMed

    Skoog, Shelby A; Goering, Peter L; Narayan, Roger J

    2014-03-01

    Several recent research efforts have focused on use of computer-aided additive fabrication technologies, commonly referred to as additive manufacturing, rapid prototyping, solid freeform fabrication, or three-dimensional printing technologies, to create structures for tissue engineering. For example, scaffolds for tissue engineering may be processed using rapid prototyping technologies, which serve as matrices for cell ingrowth, vascularization, as well as transport of nutrients and waste. Stereolithography is a photopolymerization-based rapid prototyping technology that involves computer-driven and spatially controlled irradiation of liquid resin. This technology enables structures with precise microscale features to be prepared directly from a computer model. In this review, use of stereolithography for processing trimethylene carbonate, polycaprolactone, and poly(D,L-lactide) poly(propylene fumarate)-based materials is considered. In addition, incorporation of bioceramic fillers for fabrication of bioceramic scaffolds is reviewed. Use of stereolithography for processing of patient-specific implantable scaffolds is also discussed. In addition, use of photopolymerization-based rapid prototyping technology, known as two-photon polymerization, for production of tissue engineering scaffolds with smaller features than conventional stereolithography technology is considered.

  17. Connective Tissue Ulcers

    PubMed Central

    Dabiri, Ganary; Falanga, Vincent

    2013-01-01

    Connective tissue disorders (CTD), which are often also termed collagen vascular diseases, include a number of related inflammatory conditions. Some of these diseases include rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis (scleroderma), localized scleroderma (morphea variants localized to the skin), Sjogren’s syndrome, dermatomyositis, polymyositis, and mixed connective tissue disease. In addition to the systemic manifestations of these diseases, there are a number of cutaneous features that make these conditions recognizable on physical exam. Lower extremity ulcers and digital ulcers are an infrequent but disabling complication of long-standing connective tissue disease. The exact frequency with which these ulcers occur is not known, and the cause of the ulcerations is often multifactorial. Moreover, a challenging component of CTD ulcerations is that there are still no established guidelines for their diagnosis and treatment. The morbidity associated with these ulcerations and their underlying conditions is very substantial. Indeed, these less common but intractable ulcers represent a major medical and economic problem for patients, physicians and nurses, and even well organized multidisciplinary wound healing centers. PMID:23756459

  18. Steroid biosynthesis in adipose tissue.

    PubMed

    Li, Jiehan; Papadopoulos, Vassilios; Vihma, Veera

    2015-11-01

    Tissue-specific expression of steroidogenic enzymes allows the modulation of active steroid levels in a local manner. Thus, the measurement of local steroid concentrations, rather than the circulating levels, has been recognized as a more accurate indicator of the steroid action within a specific tissue. Adipose tissue, one of the largest endocrine tissues in the human body, has been established as an important site for steroid storage and metabolism. Locally produced steroids, through the enzymatic conversion from steroid precursors delivered to adipose tissue, have been proven to either functionally regulate adipose tissue metabolism, or quantitatively contribute to the whole body's steroid levels. Most recently, it has been suggested that adipose tissue may contain the steroidogenic machinery necessary for the initiation of steroid biosynthesis de novo from cholesterol. This review summarizes the evidence indicating the presence of the entire steroidogenic apparatus in adipose tissue and discusses the potential roles of local steroid products in modulating adipose tissue activity and other metabolic parameters.

  19. Recent advances in protein profiling of tissues and tissue fluids.

    PubMed

    Yang, Shi; Huang, Chun-Ming

    2007-08-01

    Creating protein profiles of tissues and tissue fluids, which contain secreted proteins and peptides released from various cells, is critical for biomarker discovery as well as drug and vaccine target selection. It is extremely difficult to obtain pure samples from tissues or tissue fluids, however, and identification of complex protein mixtures is still a challenge for mass spectrometry analysis. Here, we summarize recent advances in techniques for extracting proteins from tissues for mass spectrometry profiling and imaging. We also introduce a novel technique using a capillary ultrafiltration (CUF) probe to enable in vivo collection of proteins from the tissue microenvironment. The CUF probe technique is compared with existing sampling techniques, including perfusion, saline wash, fine-needle aspiration and microdialysis. In this review, we also highlight quantitative mass spectrometric proteomic approaches with, and without, stable-isotope labels. Advances in quantitative proteomics will significantly improve protein profiling of tissue and tissue fluid samples collected by CUF probes.

  20. Prediction of tissue thermal damage.

    PubMed

    Li, Xin; Zhong, Yongmin; Subic, Aleksandar; Jazar, Reza; Smith, Julian; Gu, Chengfan

    2016-04-29

    This paper presents a method to characterize tissue thermal damage by taking into account the thermal-mechanical effect of soft tissues for thermal ablation. This method integrates the bio-heating conduction and non-rigid motion dynamics to describe thermal-mechanical behaviors of soft tissues and further extends the traditional tissue damage model to characterize thermal-mechanical damage of soft tissues. Simulations and comparison analysis demonstrate that the proposed method can effectively predict tissue thermal damage and it also provides reliable guidelines for control of the thermal ablation procedure. PMID:27163325

  1. Prediction of tissue thermal damage.

    PubMed

    Li, Xin; Zhong, Yongmin; Subic, Aleksandar; Jazar, Reza; Smith, Julian; Gu, Chengfan

    2016-04-29

    This paper presents a method to characterize tissue thermal damage by taking into account the thermal-mechanical effect of soft tissues for thermal ablation. This method integrates the bio-heating conduction and non-rigid motion dynamics to describe thermal-mechanical behaviors of soft tissues and further extends the traditional tissue damage model to characterize thermal-mechanical damage of soft tissues. Simulations and comparison analysis demonstrate that the proposed method can effectively predict tissue thermal damage and it also provides reliable guidelines for control of the thermal ablation procedure.

  2. Tissue pharmacokinetics of levofloxacin in human soft tissue infections

    PubMed Central

    Bellmann, Romuald; Kuchling, Gerald; Dehghanyar, Pejman; Zeitlinger, Markus; Minar, Erich; Mayer, Bernhard X; Müller, Markus; Joukhadar, Christian

    2004-01-01

    Aims The present study addressed the ability of levofloxacin to penetrate into subcutaneous adipose tissues in patients with soft tissue infection. Methods Tissue concentrations of levofloxacin in inflamed and healthy subcutaneous adipose tissue were measured in six patients by microdialysis after administration of a single intravenous dose of 500 mg. Levofloxacin was assayed by high-performance liquid chromatography. Results The mean concentration vs time profile of free levofloxacin in plasma was identical to that in inflamed and healthy tissues. The ratios of the mean area under the free levofloxacin concentration vs time curve from 0 to 10 h (AUC(0,10 h)) in tissue to that in plasma were 1.2 ± 1.0 for inflamed and 1.1 ± 0.6 for healthy subcutaneous adipose tissue (mean ± SD). The mean difference in the ratio of the AUCtissue : AUCplasma for inflamed and healthy tissue was 0.09 (95% confidence interval −0.58, 0.759, P > 0.05). Interindividual variability in tissue penetration was high, as indicated by a coefficient of variation of approximately 82% for AUCtissue : AUCplasma ratios. Conclusions The penetration of levofloxacin into tissue appears to be unaffected by local inflammation. Our plasma and tissue data suggest that an intravenous dose of 500 mg levofloxacin provides effective antibacterial concentrations at the target site. However, in treatment resistant patients, tissue concentrations may be sub-therapeutic. PMID:15089808

  3. Tissue response: biomaterials, dental implants, and compromised osseous tissue.

    PubMed

    Babu RS, Arvind; Ogle, Orrett

    2015-04-01

    Tissue response represents an important feature in biocompatibility in implant procedures. This review article highlights the fundamental characteristics of tissue response after the implant procedure. This article also highlights the tissue response in compromised osseous conditions. Understanding the histologic events after dental implants in normal and abnormal bone reinforces the concept of case selection in dental implants.

  4. Skin tissue engineering.

    PubMed

    Mansbridge, Jonathan

    2008-01-01

    The major applications of tissue-engineered skin substitutes are in promoting the healing of acute and chronic wounds. Several approaches have been taken by commercial companies to develop products to address these conditions. Skin substitutes include both acellular and cellular devices. While acellular skin substitutes act as a template for dermal formation, this discussion mainly covers cellular devices. In addressing therapeutic applications in tissue engineering generally, a valuable precursor is an understanding of the mechanism of the underlying pathology. While this is straightforward in many cases, it has not been available for wound healing. Investigation of the mode of action of the tissue-engineered skin substitutes has led to considerable insight into the mechanism of formation, maintenance and treatment of chronic wounds. Four aspects mediating healing are considered here for their mechanism of action: (i) colonization of the wound bed by live fibroblasts in the implant, (ii) the secretion of growth factors, (iii) provision of a suitable substrate for cell migration, particularly keratinocytes and immune cells, and (iv) modification of the immune system by secretion of neutrophil recruiting chemokines. An early event in acute wound healing is an influx of neutrophils that destroy planktonic bacteria. However, if the bacteria are able to form biofilm, they become resistant to neutrophil action and prevent reepithelialization. In this situation the wound becomes chronic. In chronic wounds, fibroblasts show a senescence-like phenotype with decreased secretion of neutrophil chemoattractants that make it more likely that biofilms become established. Treatment of the chronic wounds involves debridement to eliminate biofilm, and the use of antimicrobials. A role of skin substitutes is to provide non-senescent fibroblasts that attract and activate neutrophils to prevent biofilm re-establishment. The emphasis of the conclusion is the importance of preventing

  5. Obtaining corneal tissue for keratoplasty.

    PubMed

    Navarro Martínez-Cantullera, A; Calatayud Pinuaga, M

    2016-10-01

    Cornea transplant is the most common tissue transplant in the world. In Spain, tissue donation activities depend upon transplant coordinator activities and the well-known Spanish model for organ and tissue donation. Tissue donor detection system and tissue donor evaluation is performed mainly by transplant coordinators using the Spanish model on donation. The evaluation of a potential tissue donor from detection until recovery is based on an exhaustive review of the medical and social history, physical examination, family interview to determine will of the deceased, and a laboratory screening test. Corneal acceptance criteria for transplantation have a wider spectrum than other tissues, as donors with active malignancies and infections are accepted for kearatoplasty in most tissue banks. Corneal evaluation during the whole process is performed to ensure the safety of the donor and the recipient, as well as an effective transplant. Last step before processing, corneal recovery, must be performed under standard operating procedures and in a correct environment.

  6. Tools to assess tissue quality.

    PubMed

    Neumeister, Veronique M

    2014-03-01

    Biospecimen science has recognized the importance of tissue quality for accurate molecular and biomarker analysis and efforts are made to standardize tissue procurement, processing and storage conditions of tissue samples. At the same time the field has emphasized the lack of standardization of processes between different laboratories, the variability inherent in the analytical phase and the lack of control over the pre-analytical phase of tissue processing. The problem extends back into tissue samples in biorepositories, which are often decades old and where documentation about tissue processing might not be available. This review highlights pre-analytical variations in tissue handling, processing, fixation and storage and emphasizes the effects of these variables on nucleic acids and proteins in harvested tissue. Finally current tools for quality control regarding molecular or biomarker analysis are summarized and discussed.

  7. Gram stain of tissue biopsy

    MedlinePlus

    ... stain of tissue biopsy test involves using crystal violet stain to test a sample of tissue taken ... microscope slide. The specimen is stained with crystal violet stain and goes through more processing before it ...

  8. [Human brown adipose tissue].

    PubMed

    Virtanen, Kirsi A; Nuutila, Pirjo

    2015-01-01

    Adult humans have heat-producing and energy-consuming brown adipose tissue in the clavicular region of the neck. There are two types of brown adipose cells, the so-called classic and beige adipose cells. Brown adipose cells produce heat by means of uncoupler protein 1 (UCP1) from fatty acids and sugar. By applying positron emission tomography (PET) measuring the utilization of sugar, the metabolism of brown fat has been shown to multiply in the cold, presumably influencing energy consumption. Active brown fat is most likely present in young adults, persons of normal weight and women, least likely in obese persons.

  9. Mechanisms of Laser-Tissue Interaction: II. Tissue Thermal Properties

    PubMed Central

    Ansari, Mohammad Ali; Erfanzadeh, Mohsen; Mohajerani, Ezeddin

    2013-01-01

    Laser-tissue interaction is of great interest due to its significant application in biomedical optics in both diagnostic and treatment purposes. Major aspects of the laser-tissue interaction which has to be considered in biomedical studies are the thermal properties of the tissue and the thermal changes caused by the interaction of light and tissue. In this review paper the effects of light on the tissue at different temperatures are discussed. Then, due to the noticeable importance of studying the heat transfer quantitatively, the equations governing this phenomenon are presented. Finally a method of medical diagnosis called thermography and some of its applications are explained. PMID:25606316

  10. European association of tissue banks.

    PubMed

    Cahane, Michael; van Baare, Jeroen

    2009-01-01

    Tissue banking is a specific field of medical practice. The European Association of Tissue Banks (EATB) is a scientific nonprofit organization that coordinates and supports aspects of tissue banking within Europe. The evolvement, structure and principal fields of interest and activities of the EATB are described.

  11. Scaffold-free tissue engineering: organization of the tissue cytoskeleton and its effects on tissue shape.

    PubMed

    Czajka, Caitlin A; Mehesz, Agnes Nagy; Trusk, Thomas C; Yost, Michael J; Drake, Christopher J

    2014-05-01

    Work described herein characterizes tissues formed using scaffold-free, non-adherent systems and investigates their utility in modular approaches to tissue engineering. Immunofluorescence analysis revealed that all tissues formed using scaffold-free, non-adherent systems organize tissue cortical cytoskeletons that appear to be under tension. Tension in these tissues was also evident when modules (spheroids) were used to generate larger tissues. Real-time analysis of spheroid fusion in unconstrained systems illustrated modular motion that is compatible with alterations in tensions, due to the process of disassembly/reassembly of the cortical cytoskeletons required for module fusion. Additionally, tissues generated from modules placed within constrained linear molds, which restrict modular motion, deformed upon release from molds. That tissue deformation is due in full or in part to imbalanced cortical actin cytoskeleton tensions resulting from the constraints imposed by mold systems is suggested from our finding that treatment of forming tissues with Y-27632, a selective inhibitor of ROCK phosphorylation, reduced tissue deformation. Our studies suggest that the deformation of scaffold-free tissues due to tensions mediated via the tissue cortical cytoskeleton represents a major and underappreciated challenge to modular tissue engineering.

  12. Interface tissue engineering: next phase in musculoskeletal tissue repair.

    PubMed

    Sahoo, Sambit; Teh, Thomas Kh; He, Pengfei; Toh, Siew Lok; Goh, James Ch

    2011-05-01

    Increasing incidence of musculoskeletal injuries coupled with limitations in the current treatment options have necessitated tissue engineering and regenerative medicine- based approaches. Moving forward from engineering isolated musculoskeletal tissues, research strategies are now being increasingly focused on repairing and regenerating the interfaces between dissimilar musculoskeletal tissues with the aim to achieve seamless integration of engineered musculoskeletal tissues. This article reviews the state-of-the-art in the tissue engineering of musculoskeletal tissue interfaces with a focus on Singapore's contribution in this emerging field. Various biomimetic scaffold and cellbased strategies, the use of growth factors, gene therapy and mechanical loading, as well as animal models for functional validation of the tissue engineering strategies are discussed.

  13. Broadband transmission spectroscopy in tissue: application to radiofrequency tissue fusion

    NASA Astrophysics Data System (ADS)

    Floume, Timmy; Syms, Richard R. A.; Darzi, Ara W.; Hanna, George B.

    2009-05-01

    Radiofrequency tissue fusion consists in heating apposed tissue faces, which results in their sealing. Tissue transformations must be controlled to obtain reliable reproducible seal. In this paper we demonstrate how to extract information on the two main tissue transformations, thermal damage and dehydration, from continuous wave transmission spectra. A fibre based near infrared transmission spectroscopy system is presented and described theoretically. Show demonstrate that such system can be fully modeled using ray optics considerations for the coupling of the light into optical fibers, and MC simulations of light propagation in tissue. We then develop an algorithm based on the absolute measurement of attenuation and the modified Beer Lambert Law that enables the extraction of absolute tissue hydration and information on the degree of thermal damage, via scattering losses. We also discuss the basis and limit of absolute measurement during broadband submicronic tissue transmittance spectroscopy.

  14. Acquired disorders of elastic tissue: Part II. decreased elastic tissue.

    PubMed

    Lewis, Kevan G; Bercovitch, Lionel; Dill, Sara W; Robinson-Bostom, Leslie

    2004-08-01

    Elastic fibers in the extracellular matrix are integral components of dermal connective tissue. The resilience and elasticity required for normal structure and function of the skin are attributable to the network of elastic tissue. Advances in our understanding of elastic tissue physiology provide a foundation for studying the pathogenesis of elastic tissue disorders. Many acquired disorders are nevertheless poorly understood owing to the paucity of reported cases. Several acquired disorders in which loss of dermal elastic tissue produces prominent clinical and histopathologic features have recently been described, including middermal elastolysis, papular elastorrhexis, and pseudoxanthoma-like papillary dermal elastolysis, which must be differentiated from more well-known disorders such as anetoderma, acquired cutis laxa, and acrokeratoelastoidosis. Learning objective At the conclusion of this learning activity, participants should have an understanding of the similarities and differences between acquired disorders of elastic tissue that are characterized by a loss of elastic tissue.

  15. Tissue allograft coding and traceability in USM Tissue Bank, Malaysia.

    PubMed

    Sheikh Ab Hamid, Suzina; Abd Rahman, Muhamad Nor Firdaus

    2010-11-01

    In Malaysia, tissue banking activities began in Universiti Sains Malaysia (USM) Tissue Bank in early 1990s. Since then a few other bone banks have been set up in other government hospitals and institutions. However, these banks are not governed by the national authority. In addition there is no requirement set by the national regulatory authority on coding and traceability for donated human tissues for transplantation. Hence, USM Tissue Bank has taken the initiatives to adopt a system that enables the traceability of tissues between the donor, the processed tissue and the recipient based on other international standards for tissue banks. The traceability trail has been effective and the bank is certified compliance to the international standard ISO 9001:2008. PMID:20582480

  16. Biothermomechanics of skin tissues

    NASA Astrophysics Data System (ADS)

    Xu, F.; Lu, T. J.; Seffen, K. A.

    Biothermomechanics of skin is highly interdisciplinary involving bioheat transfer, burn damage, biomechanics and neurophysiology. During heating, thermally induced mechanical stress arises due to the thermal denaturation of collagen, resulting in macroscale shrinkage. Thus, the strain, stress, temperature and thermal pain/damage are highly correlated; in other words, the problem is fully coupled. The aim of this study is to develop a computational approach to examine the heat transfer process and the heat-induced mechanical response, so that the differences among the clinically applied heating modalities can be quantified. Exact solutions for temperature, thermal damage and thermal stress for a single-layer skin model were first derived for different boundary conditions. For multilayer models, numerical simulations using the finite difference method (FDM) and finite element method (FEM) were used to analyze the temperature, burn damage and thermal stress distributions in the skin tissue. The results showed that the thermomechanical behavior of skin tissue is very complex: blood perfusion has little effect on thermal damage but large influence on skin temperature distribution, which, in turn, influences significantly the resulting thermal stress field; the stratum corneum layer, although very thin, has a large effect on the thermomechanical behavior of skin, suggesting that it should be properly accounted for in the modeling of skin thermal stresses; the stress caused by non-uniform temperature distribution in the skin may also contribute to the thermal pain sensation.

  17. Mixed connective tissue disease.

    PubMed

    Gunnarsson, Ragnar; Hetlevik, Siri Opsahl; Lilleby, Vibke; Molberg, Øyvind

    2016-02-01

    The concept of mixed connective tissue disease (MCTD) as a separate connective tissue disease (CTD) has persisted for more than four decades. High titers of antibodies targeting the U1 small nuclear ribonucleoprotein particle (U1 snRNP) in peripheral blood are a sine qua non for the diagnosis of MCTD, in addition to distinct clinical features including Raynaud's phenomenon (RP), "puffy hands," arthritis, myositis, pleuritis, pericarditis, interstitial lung disease (ILD), and pulmonary hypertension (PH). Recently, population-based epidemiology data from Norway estimated the point prevalence of adult-onset MCTD to be 3.8 per 100,000 and the mean annual incidence to be 2.1 per million per year, supporting the notion that MCTD is the least common CTD. Little is known about the etiology of MCTD, but recent genetic studies have confirmed that MCTD is a strongly HLA (​human leukocyte antigen)-linked disease, as the HLA profiles of MCTD differ distinctly from the corresponding profiles of ethnically matched healthy controls and other CTDs. In the first section of this review, we provide an update on the clinical, immunological, and genetic features of MCTD and discuss the relationship between MCTD and the other CTDs. Then we proceed to discuss the recent advances in therapy and our current understanding of prognosis and prognostic factors, especially those that are associated with the more serious pulmonary and cardiovascular complications of the disease. In the final section, we discuss some of the key, unresolved questions related to anti-RNP-associated diseases and indicate how these questions may be approached in future studies. PMID:27421219

  18. Differential tissue-on-tissue lubrication by ophthalmic formulations.

    PubMed

    Meyer, Anne E; Baier, Robert E; Chen, Huagang; Chowhan, Masood

    2007-07-01

    Tissue-on-tissue friction testing was used to determine how instillation of hydrophilic polymer-containing formulations between the "blinking" tissues would compare with lubrication by saline, alone, or an oil-emulsion preparation. Best results were obtained for a formulation that contained active demulcents polyethylene glycol (PEG 400) and propylene glycol (PG), as well as a gellable polymer hydroxypropyl guar (HP-Guar) in a borate-buffered solution, in comparison with hydroxypropylcellulose-containing and carboxymethylcellulose-containing formulations. Superior performance of all the formulations was found for lubricating tissue-on-tissue couples, compared with metal-oxide-to-metal oxide interfaces, or metal oxide-to-tissue interfaces. A reciprocating pin-on-disc type friction/wear test device articulated the intimal faces of preserved human umbilical cord vein segments under increasing loads during simulated continuous "eye-blinking" with addition of increasing weights up to 60 g/cm2, simulating maximal eyelid force on the orbital globe. The tissue-on-tissue couples moved from liquid phase lubrication to boundary lubrication. After residual formulations were rinsed away with saline, persistence of low friction at the highest loads was indicative of formulation substantivity. Human umbilical cord vein segments were utilized in saline-wetted tissue-on-tissue couples that showed variable starting coefficients of friction in the range 0.2-0.4, producing moderate tearing and disruption of the interfacial layers above the medial collagen zone. The best-performing formulations instilled to the tissues pre-wetted with saline apparently reacted separately with each tissue face to produce a lower final and persistent coefficient of friction of about 0.05. Scanning electron microscopy and light microscopy of these guar-modified tissue specimens showed only a few superficial tissue disruptions, and some interphase swelling consistent with polymer uptake. The frictional

  19. Laser-tissue photothermal interaction and tissue temperature change

    NASA Astrophysics Data System (ADS)

    Ives, Andrea K.; Chen, Wei R.; Jassemnejad, Baha; Bartels, Kenneth E.; Liu, Hong; Nordquist, John A.; Nordquist, Robert E.

    2000-06-01

    Responses of tissue to laser stimulation are crucial in both disease diagnostics and treatment. In general, when tissue absorbs laser energy photothermal interaction occurs. The most important signature of the photothermal reaction is the tissue temperature change during and after the laser irradiation. Experimentally, the tissue reaction to laser irradiation can be measured by numerous methods including direct temperature measurement and measurement of perfusion change. In this study, a multiple-channel temperature probe was used to measure tissue temperature change during irradiation of lasers with different wavelengths at different power settings. Tissue temperature in chicken breast tissue as well as skin and breast tumor of rats was measured during irradiation of an 805-nm diode laser. The vertical profiles of temperature were obtained using simultaneous measurement at several different locations. The absorption of laser energy by tissue was enhanced by injecting laser-absorbing dye into the tissue. A Nd:YAG laser of 1064-nm wavelength was also used to irradiate turkey breast tissue. Our results showed that both laser penetration ability and photothermal reaction depended on the wavelength of lasers. In the case of 805-nm laser, the temperature increased rapidly only in the region close to the laser source and the thermal equilibrium could be reached within a short time period. The laser absorbing dye drastically enhanced the thermal reaction, resulting in approximately 4-fold temperature increase. On the contrary, the laser beam with 1064-nm wavelength penetrated deeply into tissue and the tissue temperature continued increasing even after a 10-minute laser irradiation.

  20. Bioengineering Beige Adipose Tissue Therapeutics.

    PubMed

    Tharp, Kevin M; Stahl, Andreas

    2015-01-01

    Unlocking the therapeutic potential of brown/beige adipose tissue requires technological advancements that enable the controlled expansion of this uniquely thermogenic tissue. Transplantation of brown fat in small animal model systems has confirmed the expectation that brown fat expansion could possibly provide a novel therapeutic to combat obesity and related disorders. Expansion and/or stimulation of uncoupling protein-1 (UCP1)-positive adipose tissues have repeatedly demonstrated physiologically beneficial reductions in circulating glucose and lipids. The recent discovery that brown adipose tissue (BAT)-derived secreted factors positively alter whole body metabolism further expands potential benefits of brown or beige/brite adipose expansion. Unfortunately, there are no sources of transplantable BATs for human therapeutic purposes at this time. Recent developments in bioengineering, including novel hyaluronic acid-based hydrogels, have enabled non-immunogenic, functional tissue allografts that can be used to generate large quantities of UCP1-positive adipose tissue. These sophisticated tissue-engineering systems have provided the methodology to develop metabolically active brown or beige/brite adipose tissue implants with the potential to be used as a metabolic therapy. Unlike the pharmacological browning of white adipose depots, implantation of bioengineered UCP1-positive adipose tissues offers a spatially controlled therapeutic. Moving forward, new insights into the mechanisms by which extracellular cues govern stem-cell differentiation and progenitor cell recruitment may enable cell-free matrix implant approaches, which generate a niche sufficient to recruit white adipose tissue-derived stem cells and support their differentiation into functional beige/brite adipose tissues. This review summarizes clinically relevant discoveries in tissue-engineering and biology leading toward the recent development of biomaterial supported beige adipose tissue implants and

  1. Bioengineering Beige Adipose Tissue Therapeutics.

    PubMed

    Tharp, Kevin M; Stahl, Andreas

    2015-01-01

    Unlocking the therapeutic potential of brown/beige adipose tissue requires technological advancements that enable the controlled expansion of this uniquely thermogenic tissue. Transplantation of brown fat in small animal model systems has confirmed the expectation that brown fat expansion could possibly provide a novel therapeutic to combat obesity and related disorders. Expansion and/or stimulation of uncoupling protein-1 (UCP1)-positive adipose tissues have repeatedly demonstrated physiologically beneficial reductions in circulating glucose and lipids. The recent discovery that brown adipose tissue (BAT)-derived secreted factors positively alter whole body metabolism further expands potential benefits of brown or beige/brite adipose expansion. Unfortunately, there are no sources of transplantable BATs for human therapeutic purposes at this time. Recent developments in bioengineering, including novel hyaluronic acid-based hydrogels, have enabled non-immunogenic, functional tissue allografts that can be used to generate large quantities of UCP1-positive adipose tissue. These sophisticated tissue-engineering systems have provided the methodology to develop metabolically active brown or beige/brite adipose tissue implants with the potential to be used as a metabolic therapy. Unlike the pharmacological browning of white adipose depots, implantation of bioengineered UCP1-positive adipose tissues offers a spatially controlled therapeutic. Moving forward, new insights into the mechanisms by which extracellular cues govern stem-cell differentiation and progenitor cell recruitment may enable cell-free matrix implant approaches, which generate a niche sufficient to recruit white adipose tissue-derived stem cells and support their differentiation into functional beige/brite adipose tissues. This review summarizes clinically relevant discoveries in tissue-engineering and biology leading toward the recent development of biomaterial supported beige adipose tissue implants and

  2. Bioengineering Beige Adipose Tissue Therapeutics

    PubMed Central

    Tharp, Kevin M.; Stahl, Andreas

    2015-01-01

    Unlocking the therapeutic potential of brown/beige adipose tissue requires technological advancements that enable the controlled expansion of this uniquely thermogenic tissue. Transplantation of brown fat in small animal model systems has confirmed the expectation that brown fat expansion could possibly provide a novel therapeutic to combat obesity and related disorders. Expansion and/or stimulation of uncoupling protein-1 (UCP1)-positive adipose tissues have repeatedly demonstrated physiologically beneficial reductions in circulating glucose and lipids. The recent discovery that brown adipose tissue (BAT)-derived secreted factors positively alter whole body metabolism further expands potential benefits of brown or beige/brite adipose expansion. Unfortunately, there are no sources of transplantable BATs for human therapeutic purposes at this time. Recent developments in bioengineering, including novel hyaluronic acid-based hydrogels, have enabled non-immunogenic, functional tissue allografts that can be used to generate large quantities of UCP1-positive adipose tissue. These sophisticated tissue-engineering systems have provided the methodology to develop metabolically active brown or beige/brite adipose tissue implants with the potential to be used as a metabolic therapy. Unlike the pharmacological browning of white adipose depots, implantation of bioengineered UCP1-positive adipose tissues offers a spatially controlled therapeutic. Moving forward, new insights into the mechanisms by which extracellular cues govern stem-cell differentiation and progenitor cell recruitment may enable cell-free matrix implant approaches, which generate a niche sufficient to recruit white adipose tissue-derived stem cells and support their differentiation into functional beige/brite adipose tissues. This review summarizes clinically relevant discoveries in tissue-engineering and biology leading toward the recent development of biomaterial supported beige adipose tissue implants and

  3. Polarized Light Propagation in Biological Tissue and Tissue Phantoms

    SciTech Connect

    Sankaran, V.; Walsh, J.T.; Maitland, D.

    1999-12-10

    Imaging through biologic tissue relies on the discrimination of weakly scattered from multiply scattered photons. The degree of polarization can be used as the discrimination criterion by which to reject multiply scattered photons. Polarized light propagation through biologic tissue is typically studied using tissue phantoms consisting of dilute aqueous suspensions of microsphere. We show that, although such phantoms are designed to match the macroscopic scattering properties of tissue (i.e.. the scattering coefficient, {mu}{sub 3}, and scattering anisotropy, g), they do not accurately represent biologic tissue for polarization-sensitive studies. In common tissue phantoms, such as dilute Intralipid and dilute 1-{micro}m-diameter polystyrene microsphere suspensions, we find that linearly polarized light is depolarized more quickly than circularly polarized light. In dense tissue, however, where scatterers are often located in close proximity to one another, circularly polarized light is depolarized similar to or more quickly than linearly polarized light. We also demonstrate that polarized light propagates differently in dilute versus densely packed microsphere suspensions, which may account for the differences seen between polarized light propagation in common dilute tissue phantoms versus dense biologic tissue.

  4. New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262

    SciTech Connect

    Skowron, Jan; Udalski, Andrzej; Szymański, Michał K. E-mail: udalski@astrouw.edu.pl; and others

    2014-04-20

    We develop a new method to measure source proper motions in microlensing events, which can partially overcome problems due to blending. It takes advantage of the fact that the source position is known precisely from the microlensing event itself. We apply this method to the event MOA-2011-BLG-262, which has a short timescale t {sub E} = 3.8 day, a companion mass ratio q = 4.7 × 10{sup –3}, and a very high or high lens-source relative proper motion μ{sub rel} = 20 mas yr{sup –1} or 12 mas yr{sup –1} (for two possible models). These three characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly Earth-mass 'moon'. The probability of such an interpretation would be greatly increased if it could be shown that the high lens-source relative proper motion was primarily due to the lens rather than the source. Based on the long-term monitoring data of the Galactic bulge from the Optical Gravitational Lensing Experiment, we measure the source proper motion that is small, μ{sub s}=(−2.3,−0.9)±(2.8,2.6) mas yr{sup −1} in a (north, east) Galactic coordinate frame. These values are then important input into a Bayesian analysis of the event presented in a companion paper by Bennett et al.

  5. Biomimetic Materials for Tissue Engineering

    PubMed Central

    Ma, Peter X

    2008-01-01

    Tissue engineering and regenerative medicine is an exciting research area that aims at regenerative alternatives to harvested tissues for transplantation. Biomaterials play a pivotal role as scaffolds to provide three-dimensional templates and synthetic extracellular-matrix environments for tissue regeneration. It is often beneficial for the scaffolds to mimic certain advantageous characteristics of the natural extracellular matrix, or developmental or would healing programs. This article reviews current biomimetic materials approaches in tissue engineering. These include synthesis to achieve certain compositions or properties similar to those of the extracellular matrix, novel processing technologies to achieve structural features mimicking the extracellular matrix on various levels, approaches to emulate cell-extracellular matrix interactions, and biologic delivery strategies to recapitulate a signaling cascade or developmental/would-healing program. The article also provides examples of enhanced cellular/tissue functions and regenerative outcomes, demonstrating the excitement and significance of the biomimetic materials for tissue engineering and regeneration. PMID:18045729

  6. New Methods in Tissue Engineering

    PubMed Central

    Sheahan, Timothy P.; Rice, Charles M.; Bhatia, Sangeeta N.

    2015-01-01

    New insights in the study of virus and host biology in the context of viral infection are made possible by the development of model systems that faithfully recapitulate the in vivo viral life cycle. Standard tissue culture models lack critical emergent properties driven by cellular organization and in vivo–like function, whereas animal models suffer from limited susceptibility to relevant human viruses and make it difficult to perform detailed molecular manipulation and analysis. Tissue engineering techniques may enable virologists to create infection models that combine the facile manipulation and readouts of tissue culture with the virus-relevant complexity of animal models. Here, we review the state of the art in tissue engineering and describe how tissue engineering techniques may alleviate some common shortcomings of existing models of viral infection, with a particular emphasis on hepatotropic viruses. We then discuss possible future applications of tissue engineering to virology, including current challenges and potential solutions. PMID:25893203

  7. Tissue-engineered oral mucosa.

    PubMed

    Moharamzadeh, K; Colley, H; Murdoch, C; Hearnden, V; Chai, W L; Brook, I M; Thornhill, M H; Macneil, S

    2012-07-01

    Advances in tissue engineering have permitted the three-dimensional (3D) reconstruction of human oral mucosa for various in vivo and in vitro applications. Tissue-engineered oral mucosa have been further optimized in recent years for clinical applications as a suitable graft material for intra-oral and extra-oral repair and treatment of soft-tissue defects. Novel 3D in vitro models of oral diseases such as cancer, Candida, and bacterial invasion have been developed as alternatives to animal models for investigation of disease phenomena, their progression, and treatment, including evaluation of drug delivery systems. The introduction of 3D oral mucosal reconstructs has had a significant impact on the approaches to biocompatibility evaluation of dental materials and oral healthcare products as well as the study of implant-soft tissue interfaces. This review article discusses the recent advances in tissue engineering and applications of tissue-engineered human oral mucosa.

  8. Human Tissue Stimulator

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Neurodyne Corporation Human Tissue Stimulator (HTS) is a totally implantable system used for treatment of chronic pain and involuntary motion disorders by electrical stimulation. It was developed by Pacesetter Systems, Inc. in cooperation with the Applied Physics Laboratory. HTS incorporates a nickel cadmium battery, telemetry and command systems technologies of the same type as those used in NASA's Small Astronomy Satellite-3 in microminiature proportions so that the implantable element is the size of a deck of cards. The stimulator includes a rechargeable battery, an antenna and electronics to receive and process commands and to report on its own condition via telemetry, a wireless process wherein instrument data is converted to electrical signals and sent to a receiver where signals are presented as usable information. The HTS is targeted to nerve centers or to particular areas of the brain to provide relief from intractable pain or arrest involuntary motion. The nickel cadmium battery can be recharged through the skin. The first two HTS units were implanted last year and have been successful. Extensive testing is required before HTS can be made available for general use.

  9. Adipose tissue extract promotes adipose tissue regeneration in an adipose tissue engineering chamber model.

    PubMed

    Lu, Zijing; Yuan, Yi; Gao, Jianhua; Lu, Feng

    2016-05-01

    An adipose tissue engineering chamber model of spontaneous adipose tissue generation from an existing fat flap has been described. However, the chamber does not completely fill with adipose tissue in this model. Here, the effect of adipose tissue extract (ATE) on adipose tissue regeneration was investigated. In vitro, the adipogenic and angiogenic capacities of ATE were evaluated using Oil Red O and tube formation assays on adipose-derived stem cells (ASCs) and rat aortic endothelial cells (RAECs), respectively. In vivo, saline or ATE was injected into the adipose tissue engineering chamber 1 week after its implantation. At different time points post-injection, the contents were morphometrically, histologically, and immunohistochemically evaluated, and the expression of growth factors and adipogenic genes was analyzed by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR. With the exception of the baseline control group, in which fat flaps were not inserted into a chamber, the total volume of fat flap tissue increased significantly in all groups, especially in the ATE group. Better morphology and structure, a thinner capsule, and more vessels were observed in the ATE group than in the control group. Expression of angiogenic growth factors and adipogenic markers were significantly higher in the ATE group. ATE therefore significantly promoted adipose tissue regeneration and reduced capsule formation in an adipose tissue engineering chamber model. These data suggest that ATE provides a more angiogenic and adipogenic microenvironment for adipose tissue formation by releasing various cytokines and growth factors that also inhibit capsule formation.

  10. Multimodality Instrument for Tissue Characterization

    NASA Technical Reports Server (NTRS)

    Mah, Robert W. (Inventor); Andrews, Russell J. (Inventor)

    2000-01-01

    A system with multimodality instrument for tissue identification includes a computer-controlled motor driven heuristic probe with a multisensory tip is discussed. For neurosurgical applications, the instrument is mounted on a stereotactic frame for the probe to penetrate the brain in a precisely controlled fashion. The resistance of the brain tissue being penetrated is continually monitored by a miniaturized strain gauge attached to the probe tip. Other modality sensors may be mounted near the probe tip to provide real-time tissue characterizations and the ability to detect the proximity of blood vessels, thus eliminating errors normally associated with registration of pre-operative scans, tissue swelling, elastic tissue deformation, human judgement, etc., and rendering surgical procedures safer, more accurate, and efficient. A neural network, program adaptively learns the information on resistance and other characteristic features of normal brain tissue during the surgery and provides near real-time modeling. A fuzzy logic interface to the neural network program incorporates expert medical knowledge in the learning process. Identification of abnormal brain tissue is determined by the detection of change and comparison with previously learned models of abnormal brain tissues. The operation of the instrument is controlled through a user friendly graphical interface. Patient data is presented in a 3D stereographics display. Acoustic feedback of selected information may optionally be provided. Upon detection of the close proximity to blood vessels or abnormal brain tissue, the computer-controlled motor immediately stops probe penetration.

  11. Synthetic Phage for Tissue Regeneration

    PubMed Central

    Merzlyak, Anna; Lee, Seung-Wuk

    2014-01-01

    Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy. PMID:24991085

  12. Electrospun multifunctional tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Wang, Chong; Wang, Min

    2014-03-01

    Tissue engineering holds great promises in providing successful treatments of human body tissue loss that current methods are unable to treat or unable to achieve satisfactory clinical outcomes. In scaffold-based tissue engineering, a highperformance scaffold underpins the success of a tissue engineering strategy and a major direction in the field is to create multifunctional tissue engineering scaffolds for enhanced biological performance and for regenerating complex body tissues. Electrospinning can produce nanofibrous scaffolds that are highly desirable for tissue engineering. The enormous interest in electrospinning and electrospun fibrous structures by the science, engineering and medical communities has led to various developments of the electrospinning technology and wide investigations of electrospun products in many industries, including biomedical engineering, over the past two decades. It is now possible to create novel, multicomponent tissue engineering scaffolds with multiple functions. This article provides a concise review of recent advances in the R & D of electrospun multifunctional tissue engineering scaffolds. It also presents our philosophy and research in the designing and fabrication of electrospun multicomponent scaffolds with multiple functions.

  13. Geometric control of tissue morphogenesis

    PubMed Central

    Nelson, Celeste M.

    2009-01-01

    Summary Morphogenesis is the dynamic and regulated change in tissue form that leads to creation of the body plan and development of mature organs. Research over the past several decades has uncovered a multitude of genetic factors required for morphogenesis in animals. The behaviors of individual cells within a developing tissue are determined by combining these genetic signals with information from the surrounding microenvironment. At any point in time, the local microenvironment is influenced by macroscale tissue geometry, which sculpts long range signals by affecting gradients of morphogens and mechanical stresses. The geometry of a tissue thus acts as both a template and instructive cue for further morphogenesis. PMID:19167433

  14. Tissue regeneration during tissue expansion and choosing an expander

    PubMed Central

    Agrawal, K.; Agrawal, S.

    2012-01-01

    This paper reviews the various aspects of tissue regeneration during the process of tissue expansion. “Creep” and mechanical and biological “stretch” are responsible for expansion. During expansion, the epidermis thickens, the dermis thins out, vascularity improves, significant angiogenesis occurs, hair telogen phase becomes shorter and the peripheral nerves, vessels and muscle fibres lengthen. Expansion is associated with molecular changes in the tissue. Almost all these biological changes are reversible after the removal of the expander.This study is also aimed at reviewing the difficulty in deciding the volume and dimension of the expander for a defect. Basic mathematical formulae and the computer programmes for calculating the dimension of tissue expanders, although available in the literature, are not popular. A user-friendly computer programme based on the easily available Microsoft Excel spread sheet has been introduced. When we feed the area of defect and base dimension of the donor area or tissue expander, this programme calculates the volume and height of the expander. The shape of the expander is decided clinically based on the availability of the donor area and the designing of the future tissue movement. Today, tissue expansion is better understood biologically and mechanically. Clinical judgement remains indispensable in choosing the size and shape of the tissue expander. PMID:22754146

  15. Three Dimensional Optic Tissue Culture and Process

    NASA Technical Reports Server (NTRS)

    OConnor, Kim C. (Inventor); Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); Aten, Laurie A. (Inventor); Francis, Karen M. (Inventor); Caldwell, Delmar R. (Inventor); Prewett, Tacey L. (Inventor); Fitzgerald, Wendy S. (Inventor)

    1999-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioireactor at low shear conditions. The tissue forms as normal, functional tissue grows with tissue organization and extracellular matrix formation.

  16. Treatment Options for Adult Soft Tissue Sarcoma

    MedlinePlus

    ... superficial (in subcutaneous tissue with no spread into connective tissue or muscle below) or deep (in the muscle ... superficial (in subcutaneous tissue with no spread into connective tissue or muscle below) or deep (in the muscle ...

  17. Treatment Option Overview (Adult Soft Tissue Sarcoma)

    MedlinePlus

    ... superficial (in subcutaneous tissue with no spread into connective tissue or muscle below) or deep (in the muscle ... superficial (in subcutaneous tissue with no spread into connective tissue or muscle below) or deep (in the muscle ...

  18. Stages of Adult Soft Tissue Sarcoma

    MedlinePlus

    ... superficial (in subcutaneous tissue with no spread into connective tissue or muscle below) or deep (in the muscle ... superficial (in subcutaneous tissue with no spread into connective tissue or muscle below) or deep (in the muscle ...

  19. Chitin scaffolds in tissue engineering.

    PubMed

    Jayakumar, Rangasamy; Chennazhi, Krishna Prasad; Srinivasan, Sowmya; Nair, Shantikumar V; Furuike, Tetsuya; Tamura, Hiroshi

    2011-01-01

    Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine.

  20. Chitin Scaffolds in Tissue Engineering

    PubMed Central

    Jayakumar, Rangasamy; Chennazhi, Krishna Prasad; Srinivasan, Sowmya; Nair, Shantikumar V.; Furuike, Tetsuya; Tamura, Hiroshi

    2011-01-01

    Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. PMID:21673928

  1. Plant Tissues. Agricultural Lesson Plans.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

    This lesson plan is intended for use in conducting classes on plant tissues. Presented first are an attention step and a series of questions and answers designed to convey general information about plant tissues and the effect of water and minerals on them. The following topics are among those discussed: reasons why water is important to plants,…

  2. Collagen for bone tissue regeneration.

    PubMed

    Ferreira, Ana Marina; Gentile, Piergiorgio; Chiono, Valeria; Ciardelli, Gianluca

    2012-09-01

    In the last decades, increased knowledge about the organization, structure and properties of collagen (particularly concerning interactions between cells and collagen-based materials) has inspired scientists and engineers to design innovative collagen-based biomaterials and to develop novel tissue-engineering products. The design of resorbable collagen-based medical implants requires understanding the tissue/organ anatomy and biological function as well as the role of collagen's physicochemical properties and structure in tissue/organ regeneration. Bone is a complex tissue that plays a critical role in diverse metabolic processes mediated by calcium delivery as well as in hematopoiesis whilst maintaining skeleton strength. A wide variety of collagen-based scaffolds have been proposed for different tissue engineering applications. These scaffolds are designed to promote a biological response, such as cell interaction, and to work as artificial biomimetic extracellular matrices that guide tissue regeneration. This paper critically reviews the current understanding of the complex hierarchical structure and properties of native collagen molecules, and describes the scientific challenge of manufacturing collagen-based materials with suitable properties and shapes for specific biomedical applications, with special emphasis on bone tissue engineering. The analysis of the state of the art in the field reveals the presence of innovative techniques for scaffold and material manufacturing that are currently opening the way to the preparation of biomimetic substrates that modulate cell interaction for improved substitution, restoration, retention or enhancement of bone tissue function. PMID:22705634

  3. Adipose tissue macrophages: amicus adipem?

    PubMed Central

    Odegaard, Justin I.; Ganeshan, Kirthana; Chawla, Ajay

    2014-01-01

    Chronic overnutrition drives complex adaptations within both professional metabolic and bystander tissues that, despite intense investigation, are still poorly understood. Xu et al. (2013) now describe the unexpected ability of adipose tissue macrophages to buffer lipids released from obese adipocytes in a manner independent of inflammatory macrophage activation. PMID:24315364

  4. Biomaterials for tissue engineering: summary

    NASA Technical Reports Server (NTRS)

    Christenson, L.; Mikos, A. G.; Gibbons, D. F.; Picciolo, G. L.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    This article summarizes presentations and discussion at the workshop "Enabling Biomaterial Technology for Tissue Engineering," which was held during the Fifth World Biomaterials Congress in May 1996. Presentations covered the areas of material substrate architecture, barrier effects, and cellular response, including analysis of biomaterials challenges involved in producing specific tissue-engineered products.

  5. Biomedical testing of cryopreserved tissues.

    PubMed

    Costa, Blas Melissari

    2005-01-01

    The Laboratory of Biomechanics of the Testing of Materials Institute of the Uruguayan Engineering School has ongoing biomechanical research for thr last 25 years. First about fixators employed in osteosynthesis and now also on the characterisation of biological tissues. A multidisciplinary group with physicians, chemists and statistical and mechanical engineers was integrated for that purpose. Research of biological tissues is carried out together with the National Organs and Tissues Bank. All materials are provided from cadaver donors. The objective is the biomechanical evaluation of tissues to be used as all allografts and the improvement of preservation methods. Elastic properties are determined for example in compression, tensile and bending tests. Sample extraction and preparation, equipments, testing procedures and some results for tendons and bones are detailed. Evaluation of fresh and cryopreserved vascular tissues is described and conclusions about their biomechanical difference between them are drawn.

  6. Tissue printing on nitrocellulose membrane

    SciTech Connect

    Taylor, R.; Song, Yanru; Pont-Lezica, R.; Lin, Liangshiou; Ye, Zhenghua; Varner, J.E. )

    1989-04-01

    In the 1950's Daoust developed substrate film printing on gelatin and starch films to localize protease, amylase, DNAase and RNAase activities. These procedures were adapted to plant tissues by Yomo and Taylor (1973) and by Jacobsen and Knox (1973). Membranes such as nitrocellulose bind cellular materials from cut tissue surfaces with little lateral diffusion. Thus accurate chemical prints are obtained. When the tissue is pressed firmly onto nitrocellulose a physical impression is obtained which shows the anatomy of the tissue. We have used the tissue-print technique to localize (1) proteins with labeled antibodies, (2) RNA with labeled nucleic acid probes, (3) enzymes by catalytic activity, (4) glycoproteins by fluorescent lectins, (5) lectins by fluorescent sugars, (6) cysteine-rich proteins by dansylated iodoacetamide, (7) ascorbic acid by silver nitrate, (8) soluble fluorescent compounds by direct observation.

  7. Videofluorometer for imaging tissue metabolism

    NASA Astrophysics Data System (ADS)

    Kelly, Jeffrey J.; Rorvik, Dawn A.; Richmond, Keith N.; Barlow, Clyde H.

    1989-11-01

    A videofluorometer is described that directly acquires digital metabolic images of reduced nicotinamide adenine dinucleotide (NADH) fluorescence in tissue. NADH fluorescence provides an intrinsic indicator of the state of tissue mitochondrial oxidative metabolism. The device combines a computer-controlled fluorescence excitation system with digital image acquisition to quantify tissue bioenergetics in both spatial and time domains. Localized ischemia following coronary artery ligation in a perfused rat heart (model for a coronary artery occlusion heart attack) is used as an example to demonstrate the capabilities of the system. This videofluorometer permits monitoring changes in physiological state of organs and tissue without interfering with tissue metabolism. The digital nature of the acquired image allows detailed analysis of physiological features and their time dependence.

  8. Commercial considerations in tissue engineering

    PubMed Central

    Mansbridge, Jonathan

    2006-01-01

    Tissue engineering is a field with immense promise. Using the example of an early tissue-engineered skin implant, Dermagraft, factors involved in the successful commercial development of devices of this type are explored. Tissue engineering has to strike a balance between tissue culture, which is a resource-intensive activity, and business considerations that are concerned with minimizing cost and maximizing customer convenience. Bioreactor design takes place in a highly regulated environment, so factors to be incorporated into the concept include not only tissue culture considerations but also matters related to asepsis, scaleup, automation and ease of use by the final customer. Dermagraft is an allogeneic tissue. Stasis preservation, in this case cryopreservation, is essential in allogeneic tissue engineering, allowing sterility testing, inventory control and, in the case of Dermagraft, a cellular stress that may be important for hormesis following implantation. Although the use of allogeneic cells provides advantages in manufacturing under suitable conditions, it raises the spectre of immunological rejection. Such rejection has not been experienced with Dermagraft. Possible reasons for this and the vision of further application of allogeneic tissues are important considerations in future tissue-engineered cellular devices. This review illustrates approaches that indicate some of the criteria that may provide a basis for further developments. Marketing is a further requirement for success, which entails understanding of the mechanism of action of the procedure, and is illustrated for Dermagraft. The success of a tissue-engineered product is dependent on many interacting operations, some discussed here, each of which must be performed simultaneously and well. PMID:17005024

  9. Commercial considerations in tissue engineering.

    PubMed

    Mansbridge, Jonathan

    2006-10-01

    Tissue engineering is a field with immense promise. Using the example of an early tissue-engineered skin implant, Dermagraft, factors involved in the successful commercial development of devices of this type are explored. Tissue engineering has to strike a balance between tissue culture, which is a resource-intensive activity, and business considerations that are concerned with minimizing cost and maximizing customer convenience. Bioreactor design takes place in a highly regulated environment, so factors to be incorporated into the concept include not only tissue culture considerations but also matters related to asepsis, scaleup, automation and ease of use by the final customer. Dermagraft is an allogeneic tissue. Stasis preservation, in this case cryopreservation, is essential in allogeneic tissue engineering, allowing sterility testing, inventory control and, in the case of Dermagraft, a cellular stress that may be important for hormesis following implantation. Although the use of allogeneic cells provides advantages in manufacturing under suitable conditions, it raises the spectre of immunological rejection. Such rejection has not been experienced with Dermagraft. Possible reasons for this and the vision of further application of allogeneic tissues are important considerations in future tissue-engineered cellular devices. This review illustrates approaches that indicate some of the criteria that may provide a basis for further developments. Marketing is a further requirement for success, which entails understanding of the mechanism of action of the procedure, and is illustrated for Dermagraft. The success of a tissue-engineered product is dependent on many interacting operations, some discussed here, each of which must be performed simultaneously and well.

  10. Lymphoid Tissue Mesenchymal Stromal Cells in Development and Tissue Remodeling

    PubMed Central

    2016-01-01

    Secondary lymphoid organs (SLOs) are sites that facilitate cell-cell interactions required for generating adaptive immune responses. Nonhematopoietic mesenchymal stromal cells have been shown to play a critical role in SLO function, organization, and tissue homeostasis. The stromal microenvironment undergoes profound remodeling to support immune responses. However, chronic inflammatory conditions can promote uncontrolled stromal cell activation and aberrant tissue remodeling including fibrosis, thus leading to tissue damage. Despite recent advancements, the origin and role of mesenchymal stromal cells involved in SLO development and remodeling remain unclear. PMID:27190524

  11. Polarized light interaction with tissues

    NASA Astrophysics Data System (ADS)

    Tuchin, Valery V.

    2016-07-01

    This tutorial-review introduces the fundamentals of polarized light interaction with biological tissues and presents some of the recent key polarization optical methods that have made possible the quantitative studies essential for biomedical diagnostics. Tissue structures and the corresponding models showing linear and circular birefringence, dichroism, and chirality are analyzed. As the basis for a quantitative description of the interaction of polarized light with tissues, the theory of polarization transfer in a random medium is used. This theory employs the modified transfer equation for Stokes parameters to predict the polarization properties of single- and multiple-scattered optical fields. The near-order of scatterers in tissues is accounted for to provide an adequate description of tissue polarization properties. Biomedical diagnostic techniques based on polarized light detection, including polarization imaging and spectroscopy, amplitude and intensity light scattering matrix measurements, and polarization-sensitive optical coherence tomography are described. Examples of biomedical applications of these techniques for early diagnostics of cataracts, detection of precancer, and prediction of skin disease are presented. The substantial reduction of light scattering multiplicity at tissue optical clearing that leads to a lesser influence of scattering on the measured intrinsic polarization properties of the tissue and allows for more precise quantification of these properties is demonstrated.

  12. Trade in human tissue products.

    PubMed

    Tonti-Filippini, Nicholas; Zeps, Nikolajs

    2011-03-01

    Trade in human tissue in Australia is prohibited by state law, and in ethical guidelines by the National Health and Medical Research Council: National statement on ethical conduct in human research; Organ and tissue donation by living donors: guidelines for ethical practice for health professionals. However, trade in human tissue products is a common practice especially for: reconstructive orthopaedic or plastic surgery; novel human tissue products such as a replacement trachea created by using human mesenchymal stem cells; biomedical research using cell lines, DNA and protein provided through biobanks. Cost pressures on these have forced consideration of commercial models to sustain their operations. Both the existing and novel activities require a robust framework to enable commercial uses of human tissue products while maintaining community acceptability of such practices, but to date no such framework exists. In this article, we propose a model ethical framework for ethical governance which identifies specific ethical issues such as: privacy; unique value of a person's tissue; commodification of the body; equity and benefit to the community; perverse incentives; and "attenuation" as a potentially useful concept to help deal with the broad range of subjective views relevant to whether it is acceptable to commercialise certain human tissue products. PMID:21382003

  13. Tissue bioengineering and artificial organs.

    PubMed

    Llames, Sara; García, Eva; Otero Hernández, Jesús; Meana, Alvaro

    2012-01-01

    The scarcity of organs and tissues for transplant and the need of immunosuppressive drugs to avoid rejection constitute two reasons that justify organ and tissue production in the laboratory. Tissue engineering based tissues (TE) could allow to regenerate the whole organ from a fragment or even to produce several organs from an organ donor for grafting purposes. TE is based in: (1) the ex vivo expansion of cells, (2) the seeding of these expanded cells in tridimensional structures that mimic physiological conditions and, (3) grafting the prototype. In order to graft big structures it is necessary that the organ or tissue produced "ex vivo" bears a vascular tree to ensure the nutrition of its deep layers. At present, no technology has been developed to provide this vascular tree to TE derived products. Thus, these tissues must be thin enough to acquire nutrients during the first days by diffusion from surrounding tissues. This fact constitutes nowadays the greatest limitation of technologies for organ development in the laboratory.In this chapter, all these problems and their possible solutions are commented. Also, the present status of TE techniques in the regeneration of different organ systems is reviewed.

  14. [Muscles and connective tissue: histology].

    PubMed

    Delage, J-P

    2012-10-01

    Here, we give some comments about the DVD movies "Muscle Attitudes" from Endovivo productions, the movies up lighting some loss in the attention given to studies on the connective tissue, and especially them into muscles. The main characteristics of the different components in the intra-muscular connective tissue (perimysium, endomysium, epimysium) are shown here with special references to their ordered architecture and special references to their spatial distributions. This connective tissue is abundant into the muscles and is in continuity with the muscles in vicinity, with their tendons and their sheath, sticking the whole on skin. This connective tissue has also very abundant connections on the muscles fibres. It is then assumed that the connective tissue sticks every organs or cells of the locomotion system. Considering the elastic properties of the collagen fibres which are the most abundant component of connective tissue, it is possible to up light a panel of connective tissue associated functions such as the transmission of muscle contractions or the regulation of protein and energetic muscles metabolism.

  15. Developing a tissue perfusion sensor.

    PubMed

    Harvey, S L R; Parker, K H; O'Hare, D

    2007-01-01

    The development of a electrochemical tissue perfusion sensor is presented. The sensor is a platinum/platinum ring-disc microelectrode that relies on the principle of collector-generator to monitor mass transport within its vicinity. Tissue perfusion is a mass transport mechanism that describes the movement of respiratory gases, nutrients and metabolites in tissue. The sensor's capability of detecting perfusion at the cellular level in a continuous fashion is unique. This sensor will provide insight into the way nutrients and metabolites are transported in tissue especially in cases were perfusion is low such as in wounds or ischemic tissue. We present experimental work for the development and testing of the sensors in vitro. Experimental flow recordings in free steam solutions as well as the flow through tissue-like media are shown. Tests on post operative human tissue are also presented. The sensor's feature such as the continuous recoding capacities, spatial resolution and the measurement range from ml/min to microl/min are highlighted. PMID:18002549

  16. Trade in human tissue products.

    PubMed

    Tonti-Filippini, Nicholas; Zeps, Nikolajs

    2011-03-01

    Trade in human tissue in Australia is prohibited by state law, and in ethical guidelines by the National Health and Medical Research Council: National statement on ethical conduct in human research; Organ and tissue donation by living donors: guidelines for ethical practice for health professionals. However, trade in human tissue products is a common practice especially for: reconstructive orthopaedic or plastic surgery; novel human tissue products such as a replacement trachea created by using human mesenchymal stem cells; biomedical research using cell lines, DNA and protein provided through biobanks. Cost pressures on these have forced consideration of commercial models to sustain their operations. Both the existing and novel activities require a robust framework to enable commercial uses of human tissue products while maintaining community acceptability of such practices, but to date no such framework exists. In this article, we propose a model ethical framework for ethical governance which identifies specific ethical issues such as: privacy; unique value of a person's tissue; commodification of the body; equity and benefit to the community; perverse incentives; and "attenuation" as a potentially useful concept to help deal with the broad range of subjective views relevant to whether it is acceptable to commercialise certain human tissue products.

  17. Multimodality instrument for tissue characterization

    NASA Technical Reports Server (NTRS)

    Mah, Robert W. (Inventor); Andrews, Russell J. (Inventor)

    2004-01-01

    A system with multimodality instrument for tissue identification includes a computer-controlled motor driven heuristic probe with a multisensory tip. For neurosurgical applications, the instrument is mounted on a stereotactic frame for the probe to penetrate the brain in a precisely controlled fashion. The resistance of the brain tissue being penetrated is continually monitored by a miniaturized strain gauge attached to the probe tip. Other modality sensors may be mounted near the probe tip to provide real-time tissue characterizations and the ability to detect the proximity of blood vessels, thus eliminating errors normally associated with registration of pre-operative scans, tissue swelling, elastic tissue deformation, human judgement, etc., and rendering surgical procedures safer, more accurate, and efficient. A neural network program adaptively learns the information on resistance and other characteristic features of normal brain tissue during the surgery and provides near real-time modeling. A fuzzy logic interface to the neural network program incorporates expert medical knowledge in the learning process. Identification of abnormal brain tissue is determined by the detection of change and comparison with previously learned models of abnormal brain tissues. The operation of the instrument is controlled through a user friendly graphical interface. Patient data is presented in a 3D stereographics display. Acoustic feedback of selected information may optionally be provided. Upon detection of the close proximity to blood vessels or abnormal brain tissue, the computer-controlled motor immediately stops probe penetration. The use of this system will make surgical procedures safer, more accurate, and more efficient. Other applications of this system include the detection, prognosis and treatment of breast cancer, prostate cancer, spinal diseases, and use in general exploratory surgery.

  18. Tissue patterning and cellular mechanics

    PubMed Central

    Heller, Evan

    2015-01-01

    In development, cells organize into biological tissues through cell growth, migration, and differentiation. Globally, this process is dictated by a genetically encoded program in which secreted morphogens and cell–cell interactions prompt the adoption of unique cell fates. Yet, at its lowest level, development is achieved through the modification of cell–cell adhesion and actomyosin-based contractility, which set the level of tension within cells and dictate how they pack together into tissues. The regulation of tension within individual cells and across large groups of cells is a major driving force of tissue organization and the basis of all cell shape change and cell movement in development. PMID:26504164

  19. Determination of tissue endothelin levels.

    PubMed

    Wong, M; Jeng, A Y

    1995-05-01

    A methodology for the quantitation of tissue endothelin levels has been developed. About 85% of authentic endothelin-1 added to the tissue extract was recovered. Using this protocol, the levels of endothelin in various rat tissues were determined. In Wistar-Kyoto rats, the kidney was found to have the highest level of endothelin, 1120 pg/gm wet weight, followed by the spleen and liver. The brain contained only half as much of endothelin when compared with the kidney. This method can be utilized to assess the pathological role of endothelin in cardiovascular or renal diseases.

  20. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it`s usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  1. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it's usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  2. Sustainable three-dimensional tissue model of human adipose tissue.

    PubMed

    Bellas, Evangelia; Marra, Kacey G; Kaplan, David L

    2013-10-01

    The need for physiologically relevant sustainable human adipose tissue models is crucial for understanding tissue development, disease progression, in vitro drug development and soft tissue regeneration. The coculture of adipocytes differentiated from human adipose-derived stem cells, with endothelial cells, on porous silk protein matrices for at least 6 months is reported, while maintaining adipose-like outcomes. Cultures were assessed for structure and morphology (Oil Red O content and CD31 expression), metabolic functions (leptin, glycerol production, gene expression for GLUT4, and PPARγ) and cell replication (DNA content). The cocultures maintained size and shape over this extended period in static cultures, while increasing in diameter by 12.5% in spinner flask culture. Spinner flask cultures yielded improved adipose tissue outcomes overall, based on structure and function, when compared to the static cultures. This work establishes a tissue model system that can be applied to the development of chronic metabolic dysfunction systems associated with human adipose tissue, such as obesity and diabetes, due to the long term sustainable functions demonstrated here.

  3. Tissue engineering: Perfusable vascular networks

    NASA Astrophysics Data System (ADS)

    Forgacs, Gabor

    2012-09-01

    A rapid vascular casting approach that uses carbohydrate glass as a sacrificial template allows tissues to be built that can be kept alive for longer in the laboratory until needed for transplantation.

  4. Scaffolds in Tendon Tissue Engineering

    PubMed Central

    Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair. PMID:22190961

  5. Teaching Tips: Plant Tissue Testing.

    ERIC Educational Resources Information Center

    Osborne, Ed

    1991-01-01

    Plant tissue testing can be done to monitor plant nutrition levels during the growing season and diagnose nutrient deficiency problems. They can provide feedback on crop conditions and fertility needs. (Author)

  6. Mechanical Signaling in Reproductive Tissues

    PubMed Central

    Jorge, Soledad; Chang, Sydney; Barzilai, Joshua J.; Leppert, Phyllis

    2014-01-01

    The organs of the female reproductive system are among the most dynamic tissues in the human body, undergoing repeated cycles of growth and involution from puberty through menopause. To achieve such impressive plasticity, reproductive tissues must respond not only to soluble signals (hormones, growth factors, and cytokines) but also to physical cues (mechanical forces and osmotic stress) as well. Here, we review the mechanisms underlying the process of mechanotransduction—how signals are conveyed from the extracellular matrix that surrounds the cells of reproductive tissues to the downstream molecules and signaling pathways that coordinate the cellular adaptive response to external forces. Our objective was to examine how mechanical forces contribute significantly to physiological functions and pathogenesis in reproductive tissues. We highlight how widespread diseases of the reproductive tract, from preterm labor to tumors of the uterus and breast, result from an impairment in mechanical signaling. PMID:25001021

  7. Nanomaterials, Inflammation and Tissue Engineering

    PubMed Central

    Padmanabhan, Jagannath

    2014-01-01

    Nanomaterials exhibit unique properties that are absent in the bulk material because decreasing material size leads to an exponential increase in surface area, surface area to volume ratio, and effective stiffness, resulting in altered physiochemical properties. Diverse categories of nanomaterials such as nanoparticles, nanoporous scaffolds, nanopatterned surfaces, nanofibers and carbon nanotubes can be generated using advanced fabrication and processing techniques. These materials are being increasingly incorporated in tissue engineering scaffolds to facilitate the development of biomimetic substitutes to replace damaged tissues and organs. Long term success of nanomaterials in tissue engineering is contingent upon the inflammatory responses they elicit in vivo. This review seeks to summarize the recent developments in our understanding of biochemical and biophysical attributes of nanomaterials and the inflammatory responses they elicit, with a focus on strategies for nanomaterial design in tissue engineering applications. PMID:25421333

  8. Types of muscle tissue (image)

    MedlinePlus

    The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in ... heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow ...

  9. Infrared Analysis Using Tissue Paper.

    ERIC Educational Resources Information Center

    Owen, Noel L.; Wood, Steven G.

    1987-01-01

    Described is a quick, easy, and cheap, but effective method of obtaining infrared spectra of solids and nonvolatile liquids by Fourier transform infrared spectroscopy. The technique uses tissue paper as a support matrix. (RH)

  10. Tissue-engineered urinary conduits.

    PubMed

    Kates, Max; Singh, Anirudha; Matsui, Hotaka; Steinberg, Gary D; Smith, Norm D; Schoenberg, Mark P; Bivalacqua, Trinity J

    2015-03-01

    The role of tissue engineering in the cystectomy population rests on the principle of sparing healthy intestinal tissue while replacing diseased bladder. Over the last 25 years advances in cell biology and material science have improved the quality and durability of bladder replacement in animals. The neo-urinary conduit ([NUC]-Tengion) employs autologous fat smooth muscle cells which are seeded onto synthetic, biodegradable scaffolds. This seeded construct is then implanted in the patient and purportedly regenerates native urinary tissue to serve as a passive channel connecting the ureters to the skin surface. Preclinical animal studies as well as the first phase I human trial implanting the NUC are reviewed. While the ultimate goal of creating a durable, effective, tissue-engineered conduit is still in its infancy, important technical and experimental strides have been made. PMID:25677229

  11. Endoscopic subsurface imaging in tissues

    SciTech Connect

    Demos, S G; Staggs, M; Radousky, H B

    2001-02-12

    The objective of this work is to develop endoscopic subsurface optical imaging technology that will be able to image different tissue components located underneath the surface of the tissue at an imaging depth of up to 1 centimeter. This effort is based on the utilization of existing technology and components developed for medical endoscopes with the incorporation of the appropriate modifications to implement the spectral and polarization difference imaging technique. This subsurface imaging technique employs polarization and spectral light discrimination in combination with image processing to remove a large portion of the image information from the outer layers of the tissue which leads to enhancement of the contrast and image quality of subsurface tissue structures.

  12. Tissue fusion over nonadhering surfaces

    PubMed Central

    Nier, Vincent; Deforet, Maxime; Duclos, Guillaume; Yevick, Hannah G.; Cochet-Escartin, Olivier; Marcq, Philippe; Silberzan, Pascal

    2015-01-01

    Tissue fusion eliminates physical voids in a tissue to form a continuous structure and is central to many processes in development and repair. Fusion events in vivo, particularly in embryonic development, often involve the purse-string contraction of a pluricellular actomyosin cable at the free edge. However, in vitro, adhesion of the cells to their substrate favors a closure mechanism mediated by lamellipodial protrusions, which has prevented a systematic study of the purse-string mechanism. Here, we show that monolayers can cover well-controlled mesoscopic nonadherent areas much larger than a cell size by purse-string closure and that active epithelial fluctuations are required for this process. We have formulated a simple stochastic model that includes purse-string contractility, tissue fluctuations, and effective friction to qualitatively and quantitatively account for the dynamics of closure. Our data suggest that, in vivo, tissue fusion adapts to the local environment by coordinating lamellipodial protrusions and purse-string contractions. PMID:26199417

  13. Tissue engineering and reparative medicine.

    PubMed

    Sipe, Jean D

    2002-06-01

    Reparative medicine is a critical frontier in biomedical and clinical research. The National Institutes of Health Bioengineering Consortium (BECON) convened a symposium titled "Reparative Medicine: Growing Tissues and Organs," which was held on June 25 and 26, 2001 in Bethesda, Maryland. The relevant realms of cells, molecular signaling, extracellular matrix, engineering design principles, vascular assembly, bioreactors, storage and translation, and host remodeling and the immune response that are essential to tissue engineering were discussed. This overview of the scientific program summarizes the plenary talks, extended poster presentations and breakout session reports with an emphasis on scientific and technical hurdles that must be overcome to achieve the promise of restoring, replacing, or enhancing tissue and organ function that tissue engineering offers.

  14. Advances in meniscal tissue engineering.

    PubMed

    Eli, Nnaemeka; Oragui, Emeka; Khan, Wasim

    2011-01-01

    Injuries and lesions to the meniscal cartilage of the knee joint are common. As a result of its limited regenerative capacity, early degenerative changes to the articular surface frequently occur, resulting in pain and poor function. Currently available surgical interventions include repair of tears, and partial and total meniscectomy but the results are inconsistent and often poor. Interest in the field of meniscal tissue engineering with the possibilities of better treatment outcomes has grown in recent times. Current research has focused on the use of mesenchymal stem cells, fibrochondrocytes, meniscal derived cells and fibroblast-like synoviocytes in tissue engineering. Mesenchymal stem cells are multipotent cells that have been identified in a number of tissues including bone marrow and synovium. Current research is aimed at defining the correct combination of cytokines and growth factors necessary to induce specific tissue formation and includes transforming growth factor-β (TGF-β), Platelet Derived Growth Factor (PDGF) and Fibroblast Growth Factor 2 (FGF2). Scaffolds provide mechanical stability and integrity, and supply a template for three-dimensional organization of the developing tissue. A number of experimental and animal models have been used to investigate the ideal scaffolds for meniscal tissue engineering. The ideal scaffold for meniscal tissue engineering has not been identified but biodegradable scaffolds have shown the most promising results. In addition to poly-glycolic acid (PGA) and poly-lactic acid (PLLA) scaffolds, new synthetic hydrogels and collagen sponges are also being explored. There are two synthetic meniscal implants currently in clinical use and there are a number of clinical trials in the literature with good short- and medium-term results. Both products are indicated for segmental tissue loss and not for complete meniscal replacement. The long-term results of these implants are unknown and we wait to see whether they will be

  15. Magnetic resonance of calcified tissues

    PubMed Central

    Wehrli, Felix W.

    2016-01-01

    MRI of the human body is largely made possible by the favorable relaxation properties of protons of water and triacyl glycerides prevalent in soft tissues. Hard tissues – key among them bone – are generally less amenable to measurement with in vivo MR imaging techniques, not so much as a result of the lower proton density but rather due to the extremely short life-times of the proton signal in water bound to solid-like entities, typically collagen, or being trapped in micro-pores. Either mechanism can enhance T2 relaxation by up to three orders of magnitude relative to their soft-tissue counterparts. Detection of these protons requires solid-state techniques that have emerged in recent years and that promise to add a new dimension to the study of hard tissues. Alternative approaches to probe calcified tissues exploit their characteristic magnetic properties. Bone, teeth and extra-osseous calcium-containing biomaterials are unique in that they are more diamagnetic than all other tissues and thus yield information indirectly by virtue of the induced magnetic fields present in their vicinity. Progress has also been made in methods allowing very high-resolution structural imaging of trabecular and cortical bone relying on detection of the surrounding soft-tissues. This brief review, much of it drawn from work conducted in the author’s laboratory, seeks to highlight opportunities with focus on early-stage developments for image-based assessment of structure, function, physiology and mechanics of calcified tissues in humans via liquid and solid-state approaches, including proton, deuteron and phosphorus NMR and MRI. PMID:23414678

  16. Pesticidal residues in animal tissues

    USGS Publications Warehouse

    DeWitt, J.B.; Menzie, C.M.; Adomaitis, V.A.; Reichel, W.L.

    1960-01-01

    Tests with penned starlings, rats, pheasants, and ducks indicated that each species differs in sensitivity to the various pesticides. Residues in tissues are proportional to the degree of exposure during area treatment and they are also found in animals shot six or more months after treatment. The presence of more than 20-30 ppm of DDT, 20 ppm of chlordan, and 6-20 ppm of heptachlor epoxide in quail tissues indicated that the birds had ingested lethal dosages of the pesticides.

  17. Adipose tissues and thyroid hormones

    PubMed Central

    Obregon, Maria-Jesus

    2014-01-01

    The maintenance of energy balance is regulated by complex homeostatic mechanisms, including those emanating from adipose tissue. The main function of the adipose tissue is to store the excess of metabolic energy in the form of fat. The energy stored as fat can be mobilized during periods of energy deprivation (hunger, fasting, diseases). The adipose tissue has also a homeostatic role regulating energy balance and functioning as endocrine organ that secretes substances that control body homeostasis. Two adipose tissues have been identified: white and brown adipose tissues (WAT and BAT) with different phenotype, function and regulation. WAT stores energy, while BAT dissipates energy as heat. Brown and white adipocytes have different ontogenetic origin and lineage and specific markers of WAT and BAT have been identified. “Brite” or beige adipose tissue has been identified in WAT with some properties of BAT. Thyroid hormones exert pleiotropic actions, regulating the differentiation process in many tissues including the adipose tissue. Adipogenesis gives raise to mature adipocytes and is regulated by several transcription factors (c/EBPs, PPARs) that coordinately activate specific genes, resulting in the adipocyte phenotype. T3 regulates several genes involved in lipid mobilization and storage and in thermogenesis. Both WAT and BAT are targets of thyroid hormones, which regulate genes crucial for their proper function: lipogenesis, lipolysis, thermogenesis, mitochondrial function, transcription factors, the availability of nutrients. T3 acts directly through specific TREs in the gene promoters, regulating transcription factors. The deiodinases D3, D2, and D1 regulate the availability of T3. D3 is activated during proliferation, while D2 is linked to the adipocyte differentiation program, providing T3 needed for lipogenesis and thermogenesis. We examine the differences between BAT, WAT and brite/beige adipocytes and the process that lead to activation of UCP1 in WAT

  18. Photoacoustic Measurements in Brain Tissue

    SciTech Connect

    Kasili, P.M.; Mobley, J.; Vo-Dinh, T.

    1999-09-19

    In this work, we develop and evaluate the photoacoustic technique for recording spectra of white and gray mammalian brain tissues. In addition to the experimental work, we also discuss the geometric aspects of photoacoustic signal generation using collimated light. Spectra constructed from the peak-to-peak amplitude of the photoacoustic waveforms indicate differences in the two tissue types at wavelengths between 620 and 695 nm. The potential of the technique for non-invasive diagnosis is discussed.

  19. Soft tissue augmentation using Restylane.

    PubMed

    Biesman, Brian

    2004-05-01

    Soft tissue augmentation plays an important role in facial rejuvenation. To accomplish this goal, numerous materials have been used. Hyaluronic acids represent the latest family of products to become available in the United States. This article provides an introduction to the proper use of Restylane, the first hyaluronic acid product to be approved by the United States Food and Drug Administration for soft tissue augmentation.

  20. Magnetic resonance of calcified tissues

    NASA Astrophysics Data System (ADS)

    Wehrli, Felix W.

    2013-04-01

    MRI of the human body is largely made possible by the favorable relaxation properties of protons of water and triacyl glycerides prevalent in soft tissues. Hard tissues - key among them bone - are generally less amenable to measurement with in vivo MR imaging techniques, not so much as a result of the lower proton density but rather due to the extremely short life-times of the proton signal in water bound to solid-like entities, typically collagen, or being trapped in micro-pores. Either mechanism can enhance T2 relaxation by up to three orders of magnitude relative to their soft-tissue counterparts. Detection of these protons requires solid-state techniques that have emerged in recent years and that promise to add a new dimension to the study of hard tissues. Alternative approaches to probe calcified tissues exploit their characteristic magnetic properties. Bone, teeth and extra-osseous calcium-containing biomaterials are unique in that they are more diamagnetic than all other tissues and thus yield information indirectly by virtue of the induced magnetic fields present in their vicinity. Progress has also been made in methods allowing very high-resolution structural imaging of trabecular and cortical bone relying on detection of the surrounding soft-tissues. This brief review, much of it drawn from work conducted in the author's laboratory, seeks to highlight opportunities with focus on early-stage developments for image-based assessment of structure, function, physiology and mechanics of calcified tissues in humans via liquid and solid-state approaches, including proton, deuteron and phosphorus NMR and MRI.

  1. Microelastography of tissue with OCT

    NASA Astrophysics Data System (ADS)

    Schmitt, Joseph M.; Bao, Xudong; Xiao, Shaojun

    1999-04-01

    The goal of OCT elastography is to quantify microscope strain induced inside a tissue by stress applied externally. Images of internal strain or displacement may provide valuable information about pathological processes such as edema and fibrosis which are known to alter the mechanical properties of tissue.In this sty we developed experimental methods for measuring internal deformation in highly scattering tissue with OCT and applied them to tissue phantoms and living tissue. Piezoelectric actuators were configured to compress the samples in steps of 5-10 micrometers as images were captured synchronously using either a frame or a line-by-line acquisition mode. The displacements of structures inside the samples were quantified using speckle- tracking algorithms based on cross correlation or optical flow of selected features. Displacements as small as a few micrometers were measurable in heterogeneous gelatin phantoms containing scattering particles and living skin. The rules suggest that the composition of tissue layers whose elasticities differ greatly can be deduced visually from image sequences without the need for complicated image processing. However, better models are needed to transform the displacement images into quantitative maps of subtle regional variations of the elastic modulus.

  2. The cryopreservation of composite tissues

    PubMed Central

    2009-01-01

    Cryopreservation of human cells and tissue has generated great interest in the scientific community since 1949, when the cryoprotective activity of glycerol was discovered. Nowadays, it is possible to reach the optimal conditions for the cryopreservation of a homogeneous cell population or a one cell-layer tissue with the preservation of a high pourcentage of the initial cells. Success is attained when there is a high recovery rate of cell structures and tissue components after thawing. It is more delicate to obtain cryopreservation of composite tissues and much more a whole organ. The present work deals with fundamental principles of the cryobiology of biological structures, with special attention to the transfer of liquids between intra and extracellular compartments and the initiation of the formation and aggregation of ice during freezing. The consequences of various physical and chemical reactions on biological tissue are described for different cryoprotective agents. Finally, we report a review of results on cyropreservation of various tissues, on the one hand, and various organs, on the other. We also report immunomodulation of antigenic responses to cryopreserved cells and organs. PMID:20046674

  3. [Soft tissue rheumatism in erderly].

    PubMed

    Szczepański, Leszek

    2008-01-01

    Disorders of soft, peri-articular tissues are a common cause of musculoskeletal pain in elderly patients. Nevertheless, most physicians underestimate the role of soft tissue rheumatism in the pathomechanism of the pain. The impairments of soft tissue can not be diagnosed by X-rays examinations, whereas degenerative lesions of joints are easy diagnosed using this method even despite of their uncertain role in producing the symptoms. The incidence of pain syndromes originated from soft tissues differ regarding to the age of patients. In young subjects the incidence of all of them is generally low. Syndromes provoked by overloading during work: repetitive strain syndrome, canal tunnel syndrome, tennis elbow, golfers elbow, shoulder tendon coin disorders and myofascial pain syndrome are common in middle-aged patients. The morbidity of fibromialgia syndrome is also lower in old people probably as the result of diminished numbers and degenerative changes in nociceptive fibers. The syndromes prevailing in elderly patients include trochanteric syndrome and the pain syndromes provoked by muscle spasm depended on posture abnormalities. In the soft tissue pain syndrome prevention adapted to old age kinesitherapy and avoiding muscle overloading are recommended. Soft tissue pain syndromes are usually treated with non steroidal anti inflammatory drugs. In local pain syndromes better results can be obtained by local treatment. Local injections of glikocorticosteroids are usually very effective and safe.

  4. The growth of tissue engineering.

    PubMed

    Lysaght, M J; Reyes, J

    2001-10-01

    This report draws upon data from a variety of sources to estimate the size, scope, and growth rate of the contemporary tissue engineering enterprise. At the beginning of 2001, tissue engineering research and development was being pursued by 3,300 scientists and support staff in more than 70 startup companies or business units with a combined annual expenditure of over $600 million. Spending by tissue engineering firms has been growing at a compound annual rate of 16%, and the aggregate investment since 1990 now exceeds $3.5 billion. At the beginning of 2001, the net capital value of the 16 publicly traded tissue engineering startups had reached $2.6 billion. Firms focusing on structural applications (skin, cartilage, bone, cardiac prosthesis, and the like) comprise the fastest growing segment. In contrast, efforts in biohybrid organs and other metabolic applications have contracted over the past few years. The number of companies involved in stem cells and regenerative medicine is rapidly increasing, and this area represents the most likely nidus of future growth for tissue engineering. A notable recent trend has been the emergence of a strong commercial activity in tissue engineering outside the United States, with at least 16 European or Australian companies (22% of total) now active.

  5. Melanin content of hamster tissues, human tissues, and various melanomas

    SciTech Connect

    Watts, K.P.; Fairchild, R.G.; Slatkin, D.N.; Greenberg, D.; Packer, S.; Atkins, H.L.; Hannon, S.J.

    1981-02-01

    Melanin content (percentage by weight) was determined in both pigmented and nonpigmented tissues of Syrian golden hamsters bearing Greene melanoma. Melanin content was also measured in various other melanoma models (B-16 in C57 mice, Harding-Passey in BALB/c mice, and KHDD in C3H mice) and in nine human melanomas, as well as in selected normal tissues. The purpose was to evaluate the possible efficacy of chlorpromazine, which is known to bind to melanin, as a vehicle for boron transport in neutron capture therapy. Successful therapy would depend upon selective uptake and absolute concentration of borated compounds in tumors; these parameters will in turn depend upon melanin concentration in melanomas and nonpigmented ''background'' tissues. Hamster whole eyes, hamster melanomas, and other well-pigmented animal melanomas were found to contain 0.3 to 0.8% melanin by weight, whereas human melanomas varied from 0.1 to 0.9% (average, 0.35%). Other tissues, with the exception of skin, were lower in content by a factor of greater than or equal to30. Melanin pigment was extracted from tissues, and the melanin content was determined spectrophotometrically. Measurements were found to be sensitive to the presence of other proteins. Previous procedures for isolating and quantifying melanin often neglected the importance of removing proteins and other interfering nonmelanic substances.

  6. Nanostructured Biomaterials for Tissue Engineered Bone Tissue Reconstruction

    PubMed Central

    Chiara, Gardin; Letizia, Ferroni; Lorenzo, Favero; Edoardo, Stellini; Diego, Stomaci; Stefano, Sivolella; Eriberto, Bressan; Barbara, Zavan

    2012-01-01

    Bone tissue engineering strategies are emerging as attractive alternatives to autografts and allografts in bone tissue reconstruction, in particular thanks to their association with nanotechnologies. Nanostructured biomaterials, indeed, mimic the extracellular matrix (ECM) of the natural bone, creating an artificial microenvironment that promotes cell adhesion, proliferation and differentiation. At the same time, the possibility to easily isolate mesenchymal stem cells (MSCs) from different adult tissues together with their multi-lineage differentiation potential makes them an interesting tool in the field of bone tissue engineering. This review gives an overview of the most promising nanostructured biomaterials, used alone or in combination with MSCs, which could in future be employed as bone substitutes. Recent works indicate that composite scaffolds made of ceramics/metals or ceramics/polymers are undoubtedly more effective than the single counterparts in terms of osteoconductivity, osteogenicity and osteoinductivity. A better understanding of the interactions between MSCs and nanostructured biomaterials will surely contribute to the progress of bone tissue engineering. PMID:22312283

  7. Secretory function of adipose tissue.

    PubMed

    Kuryszko, J; Sławuta, P; Sapikowski, G

    2016-01-01

    There are two kinds of adipose tissue in mammals: white adipose tissue - WAT and brown adipose tissue - BAT. The main function of WAT is accumulation of triacylglycerols whereas the function of BAT is heat generation. At present, WAT is also considered to be an endocrine gland that produces bioactive adipokines, which take part in glucose and lipid metabolism. Considering its endocrine function, the adipose tissue is not a homogeneous gland but a group of a few glands which act differently. Studies on the secretory function of WAT began in 1994 after discovery of leptin known as the satiation hormone, which regulates body energy homeostasis and maintainence of body mass. Apart from leptin, the following belong to adipokines: adiponectin, resistin, apelin, visfatin and cytokines: TNF and IL 6. Adiponectin is a polypeptide hormone of antidiabetic, anti-inflammatory and anti-atherogenic activity. It plays a key role in carbohydrate and fat metabolism. Resistin exerts a counter effect compared to adiponectin and its physiological role is to maintain fasting glycaemia. Visfatin stimulates insulin secretion and increases insulin sensitivity and glucose uptake by muscle cells and adipocytes. Apelin probably increases the insulin sensitivity of tissues. TNF evokes insulin resistance by blocking insulin receptors and inhibits insulin secretion. Approximately 30% of circulating IL 6 comes from adipose tissue. It causes insulin resistance by decreasing the expression of insulin receptors, decreases adipogenesis and adiponectin and visfatin secretion, and stimulates hepatic gluconeogenesis. In 2004, Bays introduced the notion of adiposopathy, defined as dysfunction of the adipose tissue, whose main feature is insulin and leptin resistance as well as the production of inflammatory cytokines: TNF and IL 6 and monocyte chemoattractant protein. This means that excess of adipose tissue, especially visceral adipose tissue, leads to the development of a chronic subclinical

  8. Bioactive glass in tissue engineering

    PubMed Central

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  9. Bioactive glass in tissue engineering.

    PubMed

    Rahaman, Mohamed N; Day, Delbert E; Bal, B Sonny; Fu, Qiang; Jung, Steven B; Bonewald, Lynda F; Tomsia, Antoni P

    2011-06-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed.

  10. Drugs Approved for Soft Tissue Sarcoma

    MedlinePlus

    ... Professionals Questions to Ask about Your Treatment Research Drugs Approved for Soft Tissue Sarcoma This page lists ... soft tissue sarcoma that are not listed here. Drugs Approved for Soft Tissue Sarcoma Cosmegen (Dactinomycin) Dactinomycin ...

  11. Donation FAQs (Bone and Tissue Allografts)

    MedlinePlus

    ... donor family services. Most organ, tissue and eye banks that are members of MTF send tissue to ... according to exact surgical specifications. Small, local tissue banks could not provide this level of quality in ...

  12. Three dimensional optic tissue culture and process

    NASA Technical Reports Server (NTRS)

    Spaulding, Glenn F. (Inventor); Prewett, Tacey L. (Inventor); Goodwin, Thomas J. (Inventor); Francis, Karen M. (Inventor); Cardwell, Delmar R. (Inventor); Oconnor, Kim (Inventor); Fitzgerald, Wendy S. (Inventor); Aten, Laurie A. (Inventor)

    1994-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioreactor at low shear conditions. The tissue forms normal, functional tissue organization and extracellular matrix.

  13. Engineering of implantable liver tissues.

    PubMed

    Sakai, Yasuyuki; Nishikawa, M; Evenou, F; Hamon, M; Huang, H; Montagne, K P; Kojima, N; Fujii, T; Niino, T

    2012-01-01

    In this chapter, from the engineering point of view, we introduce the results from our group and related research on three typical configurations of engineered liver tissues; cell sheet-based tissues, sheet-like macroporous scaffold-based tissues, and tissues based on special scaffolds that comprise a flow channel network. The former two do not necessitate in vitro prevascularization and are thus promising in actual human clinical trials for liver diseases that can be recovered by relatively smaller tissue mass. The third approach can implant a much larger mass but is still not yet feasible. In all cases, oxygen supply is the key engineering factor. For the first configuration, direct oxygen supply using an oxygen-permeable polydimethylsiloxane membrane enables various liver cells to exhibit distinct behaviors, complete double layers of mature hepatocytes and fibroblasts, spontaneous thick tissue formation of hepatocarcinoma cells and fetal hepatocytes. Actual oxygen concentration at the cell level can be strictly controlled in this culture system. Using this property, we found that initially low then subsequently high oxygen concentrations were favorable to growth and maturation of fetal cells. For the second configuration, combination of poly-L: -lactic acid 3D scaffolds and appropriate growth factor cocktails provides a suitable microenvironment for the maturation of cells in vitro but the cell growth is limited to a certain distance from the inner surfaces of the macropores. However, implantation to the mesentery leaves of animals allows the cells again to proliferate and pack the remaining spaces of the macroporous structure, suggesting the high feasibility of 3D culture of hepatocyte progenitors for liver tissue-based therapies. For the third configuration, we proposed a design criterion concerning the dimensions of flow channels based on oxygen diffusion and consumption around the channel. Due to the current limitation in the resolution of 3D

  14. FATIGUE OF BIOMATERIALS: HARD TISSUES.

    PubMed

    Arola, D; Bajaj, D; Ivancik, J; Majd, H; Zhang, D

    2010-09-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions.

  15. Multiphoton tomography for tissue engineering

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2008-02-01

    Femtosecond laser multiphoton tomography has been employed in the field of tissue engineering to perform 3D high-resolution imaging of the extracellular matrix proteins elastin and collagen as well as of living cells without any fixation, slicing, and staining. Near infrared 80 MHz picojoule femtosecond laser pulses are able to excite the endogenous fluorophores NAD(P)H, flavoproteins, melanin, and elastin via a non-resonant two-photon excitation process. In addition, collagen can be imaged by second harmonic generation. Using a two-PMT detection system, the ratio of elastin to collagen was determined during optical sectioning. A high submicron spatial resolution and 50 picosecond temporal resolution was achieved using galvoscan mirrors and piezodriven focusing optics as well as a time-correlated single photon counting module with a fast microchannel plate detector and fast photomultipliers. Multiphoton tomography has been used to optimize the tissue engineering of heart valves and vessels in bioincubators as well as to characterize artificial skin. Stem cell characterization and manipulation are of major interest for the field of tissue engineering. Using the novel sub-20 femtosecond multiphoton nanoprocessing laser microscope FemtOgene, the differentiation of human stem cells within spheroids has been in vivo monitored with submicron resolution. In addition, the efficient targeted transfection has been demonstrated. Clinical studies on the interaction of tissue-engineered products with the natural tissue environment can be performed with in vivo multiphoton tomograph DermaInspect.

  16. Synthetic biology meets tissue engineering.

    PubMed

    Davies, Jamie A; Cachat, Elise

    2016-06-15

    Classical tissue engineering is aimed mainly at producing anatomically and physiologically realistic replacements for normal human tissues. It is done either by encouraging cellular colonization of manufactured matrices or cellular recolonization of decellularized natural extracellular matrices from donor organs, or by allowing cells to self-organize into organs as they do during fetal life. For repair of normal bodies, this will be adequate but there are reasons for making unusual, non-evolved tissues (repair of unusual bodies, interface to electromechanical prostheses, incorporating living cells into life-support machines). Synthetic biology is aimed mainly at engineering cells so that they can perform custom functions: applying synthetic biological approaches to tissue engineering may be one way of engineering custom structures. In this article, we outline the 'embryological cycle' of patterning, differentiation and morphogenesis and review progress that has been made in constructing synthetic biological systems to reproduce these processes in new ways. The state-of-the-art remains a long way from making truly synthetic tissues, but there are now at least foundations for future work. PMID:27284030

  17. FATIGUE OF BIOMATERIALS: HARD TISSUES

    PubMed Central

    Arola, D.; Bajaj, D.; Ivancik, J.; Majd, H.; Zhang, D.

    2009-01-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

  18. Interface dynamics of competing tissues

    NASA Astrophysics Data System (ADS)

    Podewitz, Nils; Jülicher, Frank; Gompper, Gerhard; Elgeti, Jens

    2016-08-01

    Tissues can be characterized by their homeostatic stress, i.e. the value of stress for which cell division and cell death balance. When two different tissues grow in competition, a difference of their homeostatic stresses determines which tissue grows at the expense of the second. This then leads to the propagation of the interface separating the tissues. Here, we study structural and dynamical properties of this interface by combining continuum theory with mesoscopic simulations of a cell-based model. Using a simulation box that moves with the interface, we find that a stationary state exists in which the interface has a finite width and propagates with a constant velocity. The propagation velocity in the simulations depends linearly on the homeostatic stress difference, in excellent agreement with the analytical predictions. This agreement is also seen for the stress and velocity profiles. Finally, we analyzed the interface growth and roughness as a function of time and system size. We estimated growth and roughness exponents, which differ from those previously obtained for simple tissue growth.

  19. Micro- and nanotechnology in cardiovascular tissue engineering

    NASA Astrophysics Data System (ADS)

    Zhang, Boyang; Xiao, Yun; Hsieh, Anne; Thavandiran, Nimalan; Radisic, Milica

    2011-12-01

    While in nature the formation of complex tissues is gradually shaped by the long journey of development, in tissue engineering constructing complex tissues relies heavily on our ability to directly manipulate and control the micro-cellular environment in vitro. Not surprisingly, advancements in both microfabrication and nanofabrication have powered the field of tissue engineering in many aspects. Focusing on cardiac tissue engineering, this paper highlights the applications of fabrication techniques in various aspects of tissue engineering research: (1) cell responses to micro- and nanopatterned topographical cues, (2) cell responses to patterned biochemical cues, (3) controlled 3D scaffolds, (4) patterned tissue vascularization and (5) electromechanical regulation of tissue assembly and function.

  20. Tissue engineering chamber promotes adipose tissue regeneration in adipose tissue engineering models through induced aseptic inflammation.

    PubMed

    Peng, Zhangsong; Dong, Ziqing; Chang, Qiang; Zhan, Weiqing; Zeng, Zhaowei; Zhang, Shengchang; Lu, Feng

    2014-11-01

    Tissue engineering chamber (TEC) makes it possible to generate significant amounts of mature, vascularized, stable, and transferable adipose tissue. However, little is known about the role of the chamber in tissue engineering. Therefore, to investigate the role of inflammatory response and the change in mechanotransduction started by TEC after implantation, we placed a unique TEC model on the surface of the groin fat pads in rats to study the expression of cytokines and tissue development in the TEC. The number of infiltrating cells was counted, and vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1) expression levels in the chamber at multiple time points postimplantation were analyzed by enzyme-linked immunosorbent assay. Tissue samples were collected at various time points and labeled for specific cell populations. The result showed that new adipose tissue formed in the chamber at day 60. Also, the expression of MCP-1 and VEGF in the chamber decreased slightly from an early stage as well as the number of the infiltrating cells. A large number of CD34+/perilipin- perivascular cells could be detected at day 30. Also, the CD34+/perilipin+ adipose precursor cell numbers increased sharply by day 45 and then decreased by day 60. CD34-/perilipin+ mature adipocytes were hard to detect in the chamber content at day 30, but their number increased and then peaked at day 60. Ki67-positive cells could be found near blood vessels and their number decreased sharply over time. Masson's trichrome showed that collagen was the dominant component of the chamber content at early stage and was replaced by newly formed small adipocytes over time. Our findings suggested that the TEC implantation could promote the proliferation of adipose precursor cells derived from local adipose tissue, increase angiogenesis, and finally lead to spontaneous adipogenesis by inducing aseptic inflammation and changing local mechanotransduction.

  1. Complications of splenic tissue reimplantation.

    PubMed Central

    Tzoracoleftherakis, E.; Alivizatos, V.; Kalfarentzos, F.; Androulakis, J.

    1991-01-01

    Splenic tissue reimplantation employing the omental implantation technique was applied in 23 patients undergoing splenectomy for traumatic or iatrogenic splenic injury. Four complications were encountered after autotransplantation (17.4%). Two of these consisted of small bowel obstruction due to postoperative adhesions and were successfully managed by lysis of the adhesions. The other two complications were aseptic necrosis of the splenic transplants and were treated with ablation of the autolysed transplants. A case of abnormal splenic tissue reimplantation in a male patient with unsuspected myelofibrosis is also discussed. He underwent an emergency laparotomy for rupture of a subcapsular splenic haematoma. It is concluded that splenic tissue implantation in the greater omentum is associated with important early morbidity and this should be taken into account whenever application of the method is considered. Images Figure 1 PMID:2018325

  2. Complications of soft tissue augmentation.

    PubMed

    Hirsch, Ranella J; Stier, Meghan

    2008-09-01

    The wide variety of dermal fillers presently available has revolutionized treatment options for patients seeking a refreshed appearance. Soft tissue fillers include both bovine and human collagens, the hyaluronans, calcium hydroxyapatite, poly-L-lactic acid, and synthetic polymers. However, soft tissue augmentation is never risk-free, and as these procedures have increased in prevalence, complications have been more frequently reported. This article describes a range of complications resulting from dermal filler injections, reviews key case studies, and discusses possible treatment options for adverse effects. While biodegradable fillers offer the least risk for the patient, location, allergic reactions, granulomas, necrosis, and infection are all serious complications that must be considered before performing soft tissue augmentation with any approved dermal filler.

  3. Dynamics of branched tissue assembly

    PubMed Central

    2012-01-01

    The assembly of cells into tissues is a complex process controlled by numerous signaling pathways to ensure the fidelity of the final structure. Tissue assembly is also very dynamic, as exemplified by the formation of branched organs. Here we present two examples of tissue assembly in branched systems that highlight this dynamic nature: formation of the tracheal network in Drosophila melanogaster and the ducts of the mammary gland in mice. Extension of the branches during tracheal development is a stereotyped process that produces identical organ geometries across individuals, whereas elongation of the ducts of the pubertal mammary gland is a non-stereotyped process that produces unique patterns. By studying these two organs, we can begin to understand the dynamic nature of development of other stereotyped and non-stereotyped branching systems, including the lung, kidney, and salivary gland. PMID:23114096

  4. Focusing light through living tissue

    NASA Astrophysics Data System (ADS)

    Vellekoop, I. M.; Aegerter, C. M.

    2010-02-01

    Tissues such as skin, fat or cuticle are non-transparent because inhomogeneities in the tissue scatter light. We demonstrate experimentally that light can be focused through turbid layers of living tissue, in spite of scattering. Our method is based on the fact that coherent light forms an interference pattern, even after hundreds of scattering events. By spatially shaping the wavefront of the incident laser beam, this interference pattern was modified to make the scattered light converge to a focus. In contrast to earlier experiments, where light was focused through solid objects, we focused light through living pupae of Drosophila melanogaster. We discuss a dynamic wavefront shaping algorithm that follows changes due to microscopic movements of scattering particles in real time. We relate the performance of the algorithm to the measured timescale of the changes in the speckle pattern and analyze our experiment in the light of Laser Doppler flowmetry. Applications in particle tracking, imaging, and optical manipulation are discussed.

  5. Triacylglycerol metabolism in adipose tissue

    PubMed Central

    Ahmadian, Maryam; Duncan, Robin E; Jaworski, Kathy; Sarkadi-Nagy, Eszter; Sul, Hei Sook

    2009-01-01

    Triacylglycerol (TAG) in adipose tissue serves as the major energy storage form in higher eukaryotes. Obesity, resulting from excess white adipose tissue, has increased dramatically in recent years resulting in a serious public health problem. Understanding of adipocyte-specific TAG synthesis and hydrolysis is critical to the development of strategies to treat and prevent obesity and its closely associated diseases, for example, Type 2 diabetes, hypertension and atherosclerosis. In this review, we present an overview of the major enzymes in TAG synthesis and lipolysis, including the recent discovery of a novel adipocyte TAG hydrolase. PMID:19194515

  6. Raman Spectroscopy of Ocular Tissue

    NASA Astrophysics Data System (ADS)

    Ermakov, Igor V.; Sharifzadeh, Mohsen; Gellermann, Warner

    The optically transparent nature of the human eye has motivated numerous Raman studies aimed at the non-invasive optical probing of ocular tissue components critical to healthy vision. Investigations include the qualitative and quantitative detection of tissue-specific molecular constituents, compositional changes occurring with development of ocular pathology, and the detection and tracking of ocular drugs and nutritional supplements. Motivated by a better understanding of the molecular mechanisms leading to cataract formation in the aging human lens, a great deal of work has centered on the Raman detection of proteins and water content in the lens. Several protein groups and the hydroxyl response are readily detectable. Changes of protein compositions can be studied in excised noncataractous tissue versus aged tissue preparations as well as in tissue samples with artificially induced cataracts. Most of these studies are carried out in vitro using suitable animal models and conventional Raman techniques. Tissue water content plays an important role in optimum light transmission of the outermost transparent ocular structure, the cornea. Using confocal Raman spectroscopy techniques, it has been possible to non-invasively measure the water to protein ratio as a measure of hydration status and to track drug-induced changes of the hydration levels in the rabbit cornea at various depths. The aqueous humor, normally supplying nutrients to cornea and lens, has an advantageous anterior location for Raman studies. Increasing efforts are pursued to non-invasively detect the presence of glucose and therapeutic concentrations of antibiotic drugs in this medium. In retinal tissue, Raman spectroscopy proves to be an important tool for research into the causes of macular degeneration, the leading cause of irreversible vision disorders and blindness in the elderly. It has been possible to detect the spectral features of advanced glycation and advanced lipooxydation end products in

  7. Tissue-engineered tracheal transplantation.

    PubMed

    Baiguera, Silvia; Birchall, Martin A; Macchiarini, Paolo

    2010-03-15

    Regenerative medicine offers new tools with which to tackle disorders for which there is currently no good therapeutic option. The trachea is an ideal organ in which to explore the clinical potential of tissue engineering because severe large airway disease is poorly managed by conventional treatments, and the success of a graft is determined only by its ability to conduct air lifelong: that is, whether it can become a sustainable biological conduit. We define the component parts of tissue engineering and review the experimental methods used to produce airway implants to date, including a recent successful, first-in-man experience. PMID:20061996

  8. Soft tissue application of lasers.

    PubMed

    Holt, Timothy L; Mann, Fred A

    2002-05-01

    Despite increasing numbers of veterinarians incorporating lasers into their clinical practices, little information has been published about laser clinical applications in soft tissue surgery. This article reviews soft tissue interaction, describes laser equipment and accessories commonly marketed to veterinarians, and discusses clinical applications of the carbon dioxide laser in a systems-based approach. A table of recommended laser tips and settings based on the authors' experiences using a carbon dioxide laser (AccuVet Novapulse LX-20SP, Bothell, WA) is provided. PMID:12064042

  9. [Adipose tissue inflammation and atherosclerosis].

    PubMed

    Shwarts, V

    2009-01-01

    Adipose tissue is an endocrine organ secreting more than 30 various adipokines which regulate wide spectrum of metabolic and immune processes. Obesity is associated with development of adipose tissue inflammation. This inflammation is characterized by infiltration with macrophages, alterations of adipokine secretion, development of insulin resistance. All these factors promote atherosclerosis. Inflammation of perivascular adipose tissue is especially important. Adipokines damage vascular endothelium via paracrine pathway. Cytokines released by macrophages as well as changes of adipokine secretion lead to endothelial dysfunction - the first stage of atherogenesis. Besides specific action curative factors used in obesity, metabolic syndrome, and diabetes mellitus also produce anti-inflammatory effect and thus diminish risk factors of cardiovascular diseases, rate of their development, and alleviate manifestations of atherosclerosis. Inflammation of adipose tissue is a connecting link between obesity and atherosclerosis. This review contains an outline of roles of various major adipokines in development of atherosclerosis as well as synopsis of anti-inflammatory and antiatherogenic effects of glytazones , metformin, rimonabant, statins, and of lowering of body weight.

  10. Artificial tissues in perfusion culture.

    PubMed

    Sittinger, M; Schultz, O; Keyszer, G; Minuth, W W; Burmester, G R

    1997-01-01

    In the stagnant environment of traditional culture dishes it is difficult to generate long term experiments or artificial tissues from human cells. For this reason a perfusion culture system with a stable supply of nutrients was developed. Human chondrocytes were seeded three-dimensionally in resorbable polymer fleeces. The cell-polymer tissues were then mounted in newly developed containers (W.W. Minuth et al, Biotechniques, 1996) and continuously perfused by fresh medium for 40 days. Samples from the effluate were analyzed daily, and the pH of the medium and glucose concentration remained stable during this period. The lactid acid concentration increased from 0.17 mg/ml to 0.35 mg/ml, which was influenced by the degradation of the resorbable polymer fibers used as three dimensional support material for the cells. This perfusion system proved to be reliable especially in long term cultures. Any components in the culture medium of the cells could be monitored without disturbances as caused by manual medium replacement. These results suggest the described perfusion culture system to be a valuable and convenient tool for many applications in tissue engineering, especially in the generation of artificial connective tissue.

  11. Hypothalamic control of adipose tissue.

    PubMed

    Stefanidis, A; Wiedmann, N M; Adler, E S; Oldfield, B J

    2014-10-01

    A detailed appreciation of the control of adipose tissue whether it be white, brown or brite/beige has never been more important to the development of a framework on which to build therapeutic strategies to combat obesity. This is because 1) the rate of fatty acid release into the circulation from lipolysis in white adipose tissue (WAT) is integrally important to the development of obesity, 2) brown adipose tissue (BAT) has now moved back to center stage with the realization that it is present in adult humans and, in its activated form, is inversely proportional to levels of obesity and 3) the identification and characterization of "brown-like" or brite/beige fat is likely to be one of the most exciting developments in adipose tissue biology in the last decade. Central to all of these developments is the role of the CNS in the control of different fat cell functions and central to CNS control is the integrative capacity of the hypothalamus. In this chapter we will attempt to detail key issues relevant to the structure and function of hypothalamic and downstream control of WAT and BAT and highlight the importance of developing an understanding of the neural input to brite/beige fat cells as a precursor to its recruitment as therapeutic target.

  12. Biomaterials in myocardial tissue engineering

    PubMed Central

    Reis, Lewis A.; Chiu, Loraine L. Y.; Feric, Nicole; Fu, Lara; Radisic, Milica

    2016-01-01

    Cardiovascular disease is the leading cause of death in the developed world, and as such there is a pressing need for treatment options. Cardiac tissue engineering emerged from the need to develop alternate sources and methods of replacing tissue damaged by cardiovascular diseases, as the ultimate treatment option for many who suffer from end-stage heart failure is a heart transplant. In this review we focus on biomaterial approaches to augment injured or impaired myocardium with specific emphasis on: the design criteria for these biomaterials; the types of scaffolds—composed of natural or synthetic biomaterials, or decellularized extracellular matrix—that have been used to develop cardiac patches and tissue models; methods to vascularize scaffolds and engineered tissue, and finally injectable biomaterials (hydrogels)designed for endogenous repair, exogenous repair or as bulking agents to maintain ventricular geometry post-infarct. The challenges facing the field and obstacles that must be overcome to develop truly clinically viable cardiac therapies are also discussed. PMID:25066525

  13. Ultrasound tomography of breast tissue

    NASA Astrophysics Data System (ADS)

    Duric, Nebojsa; Littrup, Peter J.; Holsapple, Earle; Babkin, Alex; Duncan, Robert; Kalinin, Arkady; Pevzner, Roman; Tokarev, Michael

    2003-05-01

    The Karmanos Cancer Institute is developing an ultrasound device for measuring and imaging acoustic parameters of human tissue. This paper discusses the experimental results relating to tomographic reconstructions of phantoms and tissue. The specimens were scanned by the prototype scanner at a frequency of 1.5 MHz using 2 microsecond pulses. The receivers and transmitters were positioned along a ring trajectory having a diameter of 20 cm. The ring plane is translated in the vertical direction allowing for 3-D reconstructions from stacked 2-D planes of data. All ultrasound scans were performed at 10 millimeter slice thickness to generate multiple tomographic images. In a previous SPIE paper we presented preliminary results of ultrasound tomographic reconstruction of formalin-fixed breast tissue. We now present new results from data acquired with the scanner. Images were constructed using both reflection-based and transmission based algorithms. The resulting images demonstrate the ability to detect sub-mm features and to measure acoustic properties such as sound speed. Comparison with conventional ultrasound indicates the potential for better margin definition and acoustic characterization of tissue.

  14. Cycling Rho for tissue contraction.

    PubMed

    Teo, Jessica L; Yap, Alpha S

    2016-08-29

    Cell contractility, driven by the RhoA GTPase, is a fundamental determinant of tissue morphogenesis. In this issue, Mason et al. (2016. J. Cell Biol http://dx.doi.org/10.1083/jcb.201603077) reveal that cyclic inactivation of RhoA, mediated by its antagonist, C-GAP, is essential for effective contractility to occur. PMID:27551059

  15. Platelets, inflammation and tissue regeneration.

    PubMed

    Nurden, Alan T

    2011-05-01

    Blood platelets have long been recognised to bring about primary haemostasis with deficiencies in platelet production and function manifesting in bleeding while upregulated function favourises arterial thrombosis. Yet increasing evidence indicates that platelets fulfil a much wider role in health and disease. First, they store and release a wide range of biologically active substances including the panoply of growth factors, chemokines and cytokines released from a-granules. Membrane budding gives rise to microparticles (MPs), another active participant within the blood stream. Platelets are essential for the innate immune response and combat infection (viruses, bacteria, micro-organisms). They help maintain and modulate inflammation and are a major source of pro-inflammatory molecules (e.g. P-selectin, tissue factor, CD40L, metalloproteinases). As well as promoting coagulation, they are active in fibrinolysis; wound healing, angiogenesis and bone formation as well as in maternal tissue and foetal vascular remodelling. Activated platelets and MPs intervene in the propagation of major diseases. They are major players in atherosclerosis and related diseases, pathologies of the central nervous system (Alzheimers disease, multiple sclerosis), cancer and tumour growth. They participate in other tissue-related acquired pathologies such as skin diseases and allergy, rheumatoid arthritis, liver disease; while, paradoxically, autologous platelet-rich plasma and platelet releasate are being used as an aid to promote tissue repair and cellular growth. The above mentioned roles of platelets are now discussed.

  16. Mechanical Forces Governing Tissue Dynamics

    NASA Astrophysics Data System (ADS)

    Edwards, Glenn

    2002-10-01

    We have refined a UV-laser microbeam to investigate the forces at play during morphogenesis, i.e. early biological development, in the fruit fly Drosophila (1). While the microbeam typically is used to ablate tissue with cellular spatial resolution, it has the capability for submicron and thus subcellular spatial resolution. The microbeam can be steered in two-dimensions and UV-laser dissection occurred in vivo while the tissue was imaged in real time using a (visible) laser-scanning confocal microscope. We investigated a morphogenic process, known as dorsal closure, in a genetically engineered strain of Drosophila where green fluorescent protein has been fused to a fragment of a native structural protein (2). This allowed us to visualize the fluorescing contours of two opposing, outer sheets of tissue closing over an inner tissue sheet. Time-lapse imaging captured the contours in native closure as well as in response to UV-laser dissection. Specific patterns of dissection essentially eliminated a selected force: by tracking the changes in contour geometry we estimated the relative magnitude of that force (mechanical jump). Using this approach we identified and characterized a set of forces governing tissue dynamics. We have developed a mechanical model for the dynamics of dorsal closure based on this data set. This model provides a theoretical framework for investigating defective closure in mutant flies. Dorsal closure is a model system for various aspects of cell movement in wound healing and vertebrate development. This research has been supported by the DoD MFEL Program as administered by the AFOSR and by the NIH. 1. M.S. Hutson, Y. Tokutake, M-S. Chang, J.W. Bloor, S. Venakides, D.P. Kiehart, and G.S. Edwards. "Laser dissection of morphogenetic dynamics in Drosophila dorsal closure." In preparation. 2. D.P. Kiehart, et al, J. Cell Biol. 149, 471 (2000).

  17. Tissue vibration in prolonged running.

    PubMed

    Friesenbichler, Bernd; Stirling, Lisa M; Federolf, Peter; Nigg, Benno M

    2011-01-01

    The impact force in heel-toe running initiates vibrations of soft-tissue compartments of the leg that are heavily dampened by muscle activity. This study investigated if the damping and frequency of these soft-tissue vibrations are affected by fatigue, which was categorized by the time into an exhaustive exercise. The hypotheses were tested that (H1) the vibration intensity of the triceps surae increases with increasing fatigue and (H2) the vibration frequency of the triceps surae decreases with increasing fatigue. Tissue vibrations of the triceps surae were measured with tri-axial accelerometers in 10 subjects during a run towards exhaustion. The frequency content was quantified with power spectra and wavelet analysis. Maxima of local vibration intensities were compared between the non-fatigued and fatigued states of all subjects. In axial (i.e. parallel to the tibia) and medio-lateral direction, most local maxima increased with fatigue (supporting the first hypothesis). In anterior-posterior direction no systematic changes were found. Vibration frequency was minimally affected by fatigue and frequency changes did not occur systematically, which requires the rejection of the second hypothesis. Relative to heel-strike, the maximum vibration intensity occurred significantly later in the fatigued condition in all three directions. With fatigue, the soft tissue of the triceps surae oscillated for an extended duration at increased vibration magnitudes, possibly due to the effects of fatigue on type II muscle fibers. Thus, the protective mechanism of muscle tuning seems to be reduced in a fatigued muscle and the risk of potential harm to the tissue may increase. PMID:20846656

  18. Nanotechnological strategies for engineering complex tissues

    NASA Astrophysics Data System (ADS)

    Dvir, Tal; Timko, Brian P.; Kohane, Daniel S.; Langer, Robert

    2011-01-01

    Tissue engineering aims at developing functional substitutes for damaged tissues and organs. Before transplantation, cells are generally seeded on biomaterial scaffolds that recapitulate the extracellular matrix and provide cells with information that is important for tissue development. Here we review the nanocomposite nature of the extracellular matrix, describe the design considerations for different tissues and discuss the impact of nanostructures on the properties of scaffolds and their uses in monitoring the behaviour of engineered tissues. We also examine the different nanodevices used to trigger certain processes for tissue development, and offer our view on the principal challenges and prospects of applying nanotechnology in tissue engineering.

  19. A Team Approach to Improving Tissue Management.

    PubMed

    Sions, Jacqueline A; Cheuvront, Kimberly A; Grove, Georgiana L; Beach, Myra J; Bowers, Jay W; Cendaña, Cinthia R; Hixson, Jesse R; Wilson, Mary C

    2016-04-01

    Tissue implant management can be labor intensive because of multiple storage locations and cumbersome tracking systems. The purpose of this quality improvement (QI) project was to enhance patient safety and nursing satisfaction by upgrading our tissue-management facility and processes. We created a centralized storage room for tissue implants and staffed this room during all shifts. Tissue management was executed using tracking software and transportation devices that supported tissue receipt, storage, disposition, documentation, and reporting. Our project resulted in our full compliance with tissue implant requirements from the US Food and Drug Administration (FDA) and The Joint Commission. We also reduced our documentation error rate from 3% to less than 1%, and decreased the tissue-expiration rate by 1.1%. Tissues are now delivered to ORs, which allows RNs to focus on patient care rather than retrieval of implants. Monitoring of the tissue inventory has improved, resulting in the reduction of tissue wastage.

  20. Tissue engineering and its implications in dentistry.

    PubMed

    Tyagi, Parimala; Dhindsa, Manpreet Kaur

    2009-01-01

    Tissue engineering is a novel and highly exciting field of research. With tissue engineering techniques it may be possible to repair damaged tissues or even create replacement organs. This article reviews the principles underlying key tissue engineering strategies and the typical components used. Examples of tissue engineering include passive approaches, such as dental implants, and inductive approaches, in which specific molecular signals are used to activate cells.

  1. Biomechanics and mechanobiology in functional tissue engineering.

    PubMed

    Guilak, Farshid; Butler, David L; Goldstein, Steven A; Baaijens, Frank P T

    2014-06-27

    The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of "functional tissue engineering" has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements.

  2. Intraluminal tissue welding for anastomosis

    DOEpatents

    Glinsky, M.; London, R.; Zimmerman, G.; Jacques, S.

    1998-10-27

    A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or ``welded`` using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage. 8 figs.

  3. Electrical breakdown in tissue electroporation.

    PubMed

    Guenther, Enric; Klein, Nina; Mikus, Paul; Stehling, Michael K; Rubinsky, Boris

    2015-11-27

    Electroporation, the permeabilization of the cell membrane by brief, high electric fields, has become an important technology in medicine for diverse application ranging from gene transfection to tissue ablation. There is ample anecdotal evidence that the clinical application of electroporation is often associated with loud sounds and extremely high currents that exceed the devices design limit after which the devices cease to function. The goal of this paper is to elucidate and quantify the biophysical and biochemical basis for this phenomenon. Using an experimental design that includes clinical data, a tissue phantom, sound, optical, ultrasound and MRI measurements, we show that the phenomenon is caused by electrical breakdown across ionized electrolysis produced gases near the electrodes. The breakdown occurs primarily near the cathode. Electrical breakdown during electroporation is a biophysical phenomenon of substantial importance to the outcome of clinical applications. It was ignored, until now.

  4. Intraluminal tissue welding for anastomosis

    DOEpatents

    Glinsky, Michael; London, Richard; Zimmerman, George; Jacques, Steven

    1998-10-27

    A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or "welded" using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage.

  5. Progress in free tissue transfer.

    PubMed

    O'Brien, B M; Kumar, P A

    1990-01-01

    The development of microsurgical techniques has supplied plastic surgery with a new chance to transfer tissue to nearly any recipient site of the body. Classical methods still have their value but also their limits in many circumstances. Free tissue transfer has proved its advantages, especially in covering defects in the lower extremity; but microsurgical flaps also gain ground in reconstructive surgery of the head and neck, the female breast, the abdominal wall, and the hands. This article will survey well-classified microsurgical flaps, their indications, and their limits. In addition to a description of skin, fasciocutaneous, septocutaneous, and musculocutaneous flaps, we also include the latest detailed knowledge of free transfer of muscles, vascularized tendons, nerves, bones, and even joints, digits, and jejunal transfer. An outlook toward new perspectives with so-called prefabricated flaps will also be discussed. PMID:2256350

  6. Brown adipose tissue and bone

    PubMed Central

    Lidell, M E; Enerbäck, S

    2015-01-01

    Brown adipose tissue (BAT) is capable of transforming chemically stored energy, in the form of triglycerides, into heat. Recent studies have shown that metabolically active BAT is present in a large proportion of adult humans, where its activity correlates with a favorable metabolic status. Hence, the tissue is now regarded as an interesting target for therapies against obesity and associated diseases such as type 2 diabetes, the hypothesis being that an induction of BAT would be beneficial for these disease states. Apart from the association between BAT activity and a healthier metabolic status, later studies have also shown a positive correlation between BAT volume and both bone cross-sectional area and bone mineral density, suggesting that BAT might stimulate bone anabolism. The aim of this review is to give the reader a brief overview of the BAT research field and to summarize and discuss recent findings regarding BAT being a potential player in bone metabolism. PMID:27152171

  7. Ectopic pregnancy with uterine horn encapsulation in a cat.

    PubMed

    Johnston, S D; Harish, G; Stevens, J B; Scheffler, H G

    1983-11-01

    A 4 x 7-cm free-floating cylindrical mass was found in the abdomen of a 2 1/2-year-old domestic short-hair cat at ovariohysterectomy. The left uterine horn was absent. The mass contained 2 necrotic fetuses surrounded by tissue with the histologic appearance of uterine wall. PMID:12002569

  8. Salvinia molesta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salvinia molesta is a free-floating aquatic fern. It has a horizontal stem that lies at or just below the water surface. Buoyancy is facilitated by the formation of aerenchyma tissue in the stems and leaves. Reproduction is entirely asexual: colony increase is through vegetative growth and the spre...

  9. Tissue sterility in uneviscerated carcasses.

    PubMed

    Gill, C O; Penney, N; Nottingham, P M

    1978-08-01

    Sheep muscle tissue removed aseptically from control carcasses, from uneviscerated carcasses held at 20 degrees C for 24 h, and from carcasses of sheep subjected to stress before slaughter was examined for the presence of bacteria. All samples from a total of 68 carcasses were sterile. Whole-body autoradiography of mouse carcasses showed that 14C-labeled fixed bacteria injected after death remained in the lumen of the intestine. Live bacteria did not penetrate the mucosal surface until the tissue structure had been disrupted by proteolytic enzymes. Bacteria were unable to penetrate sections of intestine longitudinally until considerable structural breakdown had occurred, indicating that blood and lymph vessels do not normally offer a pathway for microbial invasion from the intestine. Clostridia, which have been reported to be responsible for deep spoilage of meat, reached maximum numbers 24 to 28 h after death in the intestines of guinea pig carcasses stored at 20 degrees C, but did not invade carcass tissues until the stomach ruptured as a result of proteolysis between 2 and 3 days after death.

  10. Gender determination from pulpal tissue

    PubMed Central

    Khorate, Manisha M.; Dhupar, Anita; Ahmed, Junaid; Dinkar, Ajit D.

    2014-01-01

    Objective: To evaluate the diagnostic performance of X (Barr body [BB]) and Y (F body [FB]) chromosomes observed in dental pulp tissue for gender determination of an individual. Materials and Methods: The study was carried out on 100 teeth (50 male and 50 female), which were indicated for extraction. The teeth were sectioned at various intervals (within 12 h to 49 days post-extraction), and the pulpal tissue was obtained. Two slides for each pulp tissue were prepared, one for 5% Quinacrine dihydrochloride stain (FB) and the other for Hemotoxylin and Eosin stain (BB). The slides were then observed under the fluorescent microscope for FB and under the light microscope for the BB respectively. Results: Gender determination from human pulp is possible up to 7 weeks. The percentage of FB and BB decrease gradually as the time interval increases. Further, an equation was derived from the data based on the canonical discriminant function coefficients. Conclusion: The determination of gender based on a joint search for the presence or absence of X (BB) and Y (FB) Chromosome is a reliable and cost-effective technique. PMID:25125918

  11. Adipose tissue, diet and aging.

    PubMed

    Zamboni, Mauro; Rossi, Andrea P; Fantin, Francesco; Zamboni, Giulia; Chirumbolo, Salvatore; Zoico, Elena; Mazzali, Gloria

    2014-01-01

    Age related increase in body fat mass, visceral adipose tissue (AT), and ectopic fat deposition are strongly related to worse health conditions in the elderly. Moreover, with aging higher inflammation in adipose tissue may be observed and may contribute to inflammaging. Aging may significantly affect AT function by modifying the profile of adipokines produced by adipose cells, reducing preadipocytes number and their function and increasing AT macrophages infiltration. The initiating events of the inflammatory cascade promoting a greater AT inflammatory profile are not completely understood. Nutrients may determine changes in the amount of body fat, in its distribution as well as in AT function with some nutrients showing a pro-inflammatory effect on AT. Evidences are sparse and quite controversial with only a few studies performed in older subjects. Different dietary patterns are the result of the complex interaction of foods and nutrients, thus more studies are needed to evaluate the association between dietary patterns and changes in adipose tissue structure, distribution and function in the elderly.

  12. Adipose tissue immunity and cancer.

    PubMed

    Catalán, Victoria; Gómez-Ambrosi, Javier; Rodríguez, Amaia; Frühbeck, Gema

    2013-10-02

    Inflammation and altered immune response are important components of obesity and contribute greatly to the promotion of obesity-related metabolic complications, especially cancer development. Adipose tissue expansion is associated with increased infiltration of various types of immune cells from both the innate and adaptive immune systems. Thus, adipocytes and infiltrating immune cells secrete pro-inflammatory adipokines and cytokines providing a microenvironment favorable for tumor growth. Accumulation of B and T cells in adipose tissue precedes macrophage infiltration causing a chronic low-grade inflammation. Phenotypic switching toward M1 macrophages and Th1 T cells constitutes an important mechanism described in the obese state correlating with increased tumor growth risk. Other possible synergic mechanisms causing a dysfunctional adipose tissue include fatty acid-induced inflammation, oxidative stress, endoplasmic reticulum stress, and hypoxia. Recent investigations have started to unravel the intricacy of the cross-talk between tumor cell/immune cell/adipocyte. In this sense, future therapies should take into account the combination of anti-inflammatory approaches that target the tumor microenvironment with more sophisticated and selective anti-tumoral drugs.

  13. Differentiating tissue by fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Woessner, Stefan; Huen, Julien; Malthan, Dirk

    2004-03-01

    A common problem in several surgical applications is the lack of navigational information. Most often, the only source of information about the location of crucial structures, in relation to the surgical instrument, is the visible and tactile sensory input of the surgeon. In some cases, this leads to time-consuming procedures and a high risk for the patient. Therefore, we developed a spectroscopic sensor system for automatic differentiation between several tissue types. For example in milling processes, a sensor that is able to detect bone in contrast to nerve or vein tissue can be used to control the milling process. We showed exemplarily for the cochlea implant, a typical ENT-surgery, that with the help of our sensor system, the milling of bone can be accelerated without increasing the risk for the patient. It is also possible to use this type of sensor system in the area of medical robotics in soft-tissue applications. With real-time information, a continuous registration can take place, in contrast to a registration that is done using static preoperatively acquired images. We showed that our sensor system can be used to dynamically update the location of the patient in relation to CT or MR-images. In conclusion, we have been able to show that well-known spectroscopy sensors can be used to open new possibilities in medical treatment with and without the use of robotics.

  14. Optoacoustic detection of tissue glycation

    PubMed Central

    Ghazaryan, Ara; Omar, Murad; Tserevelakis, George J.; Ntziachristos, Vasilis

    2015-01-01

    Oxidative-based diseases including diabetes, chronic renal failure, cardiovascular diseases and neurological disorders are accompanied by accumulation of advanced glycation endproducts (AGE). Therefore, AGE-associated changes in tissue optical properties could yield a viable pathological indicator for disease diagnostics and monitoring. We investigated whether skin glycation could be detected based on absorption changes associated with AGE accumulation using spectral optoacoustic measurements and interrogated the optimal spectral band for skin glycation determination. Glycated and non-glycated skin was optoacoustically measured at multiple wavelengths in the visible region. The detected signals were spectrally processed and compared to measurements of skin auto-fluorescence and to second harmonic generation multiphoton microscopy images. Optoacoustic measurements are shown to be capable of detecting skin glycolysis based on AGE detection. A linear dependence was observed between optoacoustic intensity and the progression of skin glycation. The findings where corroborated by autofluorescence observations. Detection sensitivity is enhanced by observing normalised tissue spectra. This result points to a ratiometric method for skin glycation detection, specifically at 540 nm and 620 nm. We demonstrate that optoacoustic spectroscopy could be employed to detect AGE accumulation, and possibly can be employed as a non-invasive quick method for monitoring tissue glycation. PMID:26417487

  15. The history of tissue tension.

    PubMed

    Peters, W S; Tomos, A D

    1996-06-01

    In recent years the phenomenon of tissue tension and its functional connection to elongation growth has regained much interest. In the present study we reconstruct older models of mechanical inhomogenities in growing plant organs, in order to establish an accurate historical background for the current discussion. We focus on the iatromechanic model developed in Stephen Hales' Vegetable Staticks, Wilhelm Hofmeister's mechanical model of negative geotropism, Julius Sachs' explanation of the development of tissue tension, and the differential-auxin-response-hypothesis by Kenneth Thimann and Charles Schneider. Each of these models is considered in the context of its respective historic and theoretical environment. In particular, the dependency of the biomechanical hypotheses on the cell theory and the hormone concept is discussed. We arrive at the conclusion that the historical development until the middle of our century is adequately described as a development towards more detailed explanations of how differential tensions are established during elongation growth in plant organs. Then we compare with the older models the structure of more recent criticism of hormonal theories of tropic curvature, and particularly the epidermal-growth-control hypothesis of Ulrich Kutschera. In contrast to the more elaborate of the older hypotheses, the recent models do not attempt an explanation of differential tensions, but instead focus on mechanical processes in organs, in which tissue tension already exists. Some conceptual implications of this discrepancy, which apparently were overlooked in the recent discussion, are briefly evaluated. PMID:11541099

  16. Silk fibroin in tissue engineering.

    PubMed

    Kasoju, Naresh; Bora, Utpal

    2012-07-01

    Tissue engineering (TE) is a multidisciplinary field that aims at the in vitro engineering of tissues and organs by integrating science and technology of cells, materials and biochemical factors. Mimicking the natural extracellular matrix is one of the critical and challenging technological barriers, for which scaffold engineering has become a prime focus of research within the field of TE. Amongst the variety of materials tested, silk fibroin (SF) is increasingly being recognized as a promising material for scaffold fabrication. Ease of processing, excellent biocompatibility, remarkable mechanical properties and tailorable degradability of SF has been explored for fabrication of various articles such as films, porous matrices, hydrogels, nonwoven mats, etc., and has been investigated for use in various TE applications, including bone, tendon, ligament, cartilage, skin, liver, trachea, nerve, cornea, eardrum, dental, bladder, etc. The current review extensively covers the progress made in the SF-based in vitro engineering and regeneration of various human tissues and identifies opportunities for further development of this field.

  17. Bone and Soft Tissue Ablation

    PubMed Central

    Foster, Ryan C.B.; Stavas, Joseph M.

    2014-01-01

    Bone and soft tissue tumor ablation has reached widespread acceptance in the locoregional treatment of various benign and malignant musculoskeletal (MSK) lesions. Many principles of ablation learned elsewhere in the body are easily adapted to the MSK system, particularly the various technical aspects of probe/antenna design, tumoricidal effects, selection of image guidance, and methods to reduce complications. Despite the common use of thermal and chemical ablation procedures in bone and soft tissues, there are few large clinical series that show longitudinal benefit and cost-effectiveness compared with conventional methods, namely, surgery, external beam radiation, and chemotherapy. Percutaneous radiofrequency ablation of osteoid osteomas has been evaluated the most and is considered a first-line treatment choice for many lesions. Palliation of painful metastatic bone disease with thermal ablation is considered safe and has been shown to reduce pain and analgesic use while improving quality of life for cancer patients. Procedure-related complications are rare and are typically easily managed. Similar to all interventional procedures, bone and soft tissue lesions require an integrated approach to disease management to determine the optimum type of and timing for ablation techniques within the context of the patient care plan. PMID:25053865

  18. Cardiac Conduction through Engineered Tissue

    PubMed Central

    Choi, Yeong-Hoon; Stamm, Christof; Hammer, Peter E.; Kwaku, Kevin F.; Marler, Jennifer J.; Friehs, Ingeborg; Jones, Mara; Rader, Christine M.; Roy, Nathalie; Eddy, Mau-Thek; Triedman, John K.; Walsh, Edward P.; McGowan, Francis X.; del Nido, Pedro J.; Cowan, Douglas B.

    2006-01-01

    In children, interruption of cardiac atrioventricular (AV) electrical conduction can result from congenital defects, surgical interventions, and maternal autoimmune diseases during pregnancy. Complete AV conduction block is typically treated by implanting an electronic pacemaker device, although long-term pacing therapy in pediatric patients has significant complications. As a first step toward developing a substitute treatment, we implanted engineered tissue constructs in rat hearts to create an alternative AV conduction pathway. We found that skeletal muscle-derived cells in the constructs exhibited sustained electrical coupling through persistent expression and function of gap junction proteins. Using fluorescence in situ hybridization and polymerase chain reaction analyses, myogenic cells in the constructs were shown to survive in the AV groove of implanted hearts for the duration of the animal’s natural life. Perfusion of hearts with fluorescently labeled lectin demonstrated that implanted tissues became vascularized and immunostaining verified the presence of proteins important in electromechanical integration of myogenic cells with surrounding recipient rat cardiomyocytes. Finally, using optical mapping and electrophysiological analyses, we provide evidence of permanent AV conduction through the implant in one-third of recipient animals. Our experiments provide a proof-of-principle that engineered tissue constructs can function as an electrical conduit and, ultimately, may offer a substitute treatment to conventional pacing therapy. PMID:16816362

  19. Hematopoietic stem cell origin of connective tissues.

    PubMed

    Ogawa, Makio; Larue, Amanda C; Watson, Patricia M; Watson, Dennis K

    2010-07-01

    Connective tissue consists of "connective tissue proper," which is further divided into loose and dense (fibrous) connective tissues and "specialized connective tissues." Specialized connective tissues consist of blood, adipose tissue, cartilage, and bone. In both loose and dense connective tissues, the principal cellular element is fibroblasts. It has been generally believed that all cellular elements of connective tissue, including fibroblasts, adipocytes, chondrocytes, and bone cells, are generated solely by mesenchymal stem cells. Recently, a number of studies, including those from our laboratory based on transplantation of single hematopoietic stem cells, strongly suggested a hematopoietic stem cell origin of these adult mesenchymal tissues. This review summarizes the experimental evidence for this new paradigm and discusses its translational implications.

  20. Recent progress in tissue optical clearing

    PubMed Central

    Zhu, Dan; Larin, Kirill V; Luo, Qingming; Tuchin, Valery V

    2013-01-01

    Tissue optical clearing technique provides a prospective solution for the application of advanced optical methods in life sciences. This paper gives a review of recent developments in tissue optical clearing techniques. The physical, molecular and physiological mechanisms of tissue optical clearing are overviewed and discussed. Various methods for enhancing penetration of optical-clearing agents into tissue, such as physical methods, chemical-penetration enhancers and combination of physical and chemical methods are introduced. Combining the tissue optical clearing technique with advanced microscopy image or labeling technique, applications for 3D microstructure of whole tissues such as brain and central nervous system with unprecedented resolution are demonstrated. Moreover, the difference in diffusion and/or clearing ability of selected agents in healthy versus pathological tissues can provide a highly sensitive indicator of the tissue health/pathology condition. Finally, recent advances in optical clearing of soft or hard tissue for in vivo imaging and phototherapy are introduced. PMID:24348874

  1. Radiation sterilization of tissue allografts: A review

    PubMed Central

    Singh, Rita; Singh, Durgeshwer; Singh, Antaryami

    2016-01-01

    Tissue substitutes are required in a number of clinical conditions for treatment of injured and diseased tissues. Tissues like bone, skin, amniotic membrane and soft tissues obtained from human donor can be used for repair or reconstruction of the injured part of the body. Allograft tissues from human donor provide an excellent alternative to autografts. However, major concern with the use of allografts is the risk of infectious disease transmission. Therefore, tissue allografts should be sterilized to make them safe for clinical use. Gamma radiation has several advantages and is the most suitable method for sterilization of biological tissues. This review summarizes the use of gamma irradiation technology as an effective method for sterilization of biological tissues and ensuring safety of tissue allografts. PMID:27158422

  2. SURROGATE TISSUE ANALYSIS: MONITORING TOXICANT EXPOSURE AND HEALTH STATUS OF INACCESSIBLE TISSUES THROUGH THE ANALYSIS OF ACCESSIBLE TISSUES AND CELLS

    EPA Science Inventory

    Surrogate Tissue Analysis: Monitoring Toxicant Exposure And Health Status Of Inaccessible Tissues Through The Analysis Of Accessible Tissues And Cells*
    John C. Rockett1, Michael E. Burczynski 2, Albert J. Fornace, Jr.3, Paul.C. Herrmann4, Stephen A. Krawetz5, and David J. Dix1...

  3. Spectral Redundancy in Tissue Characterization

    NASA Astrophysics Data System (ADS)

    Varghese, Tomy

    1995-01-01

    Ultrasonic backscattered signals from material comprised of quasi-periodic scatterers exhibit redundancy over both its phase and magnitude spectra. This dissertation addresses the problem of estimating the mean scatterer spacing and scatterer density from the backscattered ultrasound signal using spectral redundancy characterized by the spectral autocorrelation (SAC) function. The SAC function exploits characteristic differences between the phase spectrum of the resolvable quasi-periodic (regular) scatterers and the unresolvable uniformly distributed (diffuse) scatterers to improve estimator performance over other estimators that operate directly on the magnitude spectrum. Analytical, simulation, and experimental results (liver and breast tissue) indicate the potential of utilizing phase information using the SAC function. A closed form analytical expression for the SAC function is derived for gamma distributed scatterer spacings. The theoretical expression for the SAC function demonstrate the increased regular-to-diffuse scatterer signal ratio in the off-diagonal components of the SAC function, since the diffuse component contributes only to the diagonal components (power spectrum). The A-scan is modelled as a cyclostationary signal whose statistical parameters vary in time with single or multiple periodicities. A-scan models consist of a collection of regular scatterers with gamma distributed spacings embedded in diffuse scatterers with uniform distributed spacings. The model accounts for attenuation by convolving the frequency dependent backscatter coefficients of the scatterer centers with a time-varying system response. Simulation results show that SAC-based estimates converge more reliably over smaller amounts of data than previously used cepstrum-based estimates. A major reason for the performance advantage is the use of phase information by the SAC function, while the cepstnun uses a phaseless power spectral density, that is directly affected by the system

  4. TNT metabolites in animal tissues

    SciTech Connect

    Shugart, L.R.; Griest, W.H.; Tan, E.; Guzman, C.; Caton, J.E.; Ho, C.-H.; Tomkins, B.A.

    1991-06-01

    Analyses for TNT and nine potential metabolites (TNT-related compounds) were made in deer, rabbit, and quail tissues (muscle and liver) taken from the Alabama Army Ammunition Plant (AAAP), Childersburg, Alabama. The listed TNT-related compounds are 2,4,6- trinitrotoluene (parent compound); 2,4-diamino-6-nitrotoluene; 2,6-diamino-4-nitrotoluene; 2-amino-4,6-dinitrotoluene; 4-amino-2,6- dinitrotoluene; 2,4,6-trinitrobenzyl alcohol; 2,4,6-trinitrobenzoic acid; 1,3,5-trinitrobenzene; 4-hydroxylamino-2,6-dinitrotoluene; and 2,6,2',6'-tetranitro-4,4'-azoxytoluene. The procedure for extraction of these compounds from animal tissue required homogenization in acetonitrile, and subsequent partitioning into chloroform. Quantitative determination of extracted compounds was obtained by chromatographic separation on a mixed-mode HPLC column in which the phase bonded to the silica surface contained both a C18 (reversed-phase function) and a secondary amine (anion exchange function) incorporated into a single ligand. A ternary mobile phase gradient containing pH 5.1 phosphate buffer, methanol, and acetonitrile was used in separation. An experimental verification of the metabolism of TNT and the detection (or absence) of the selected metabolites was performed in mice subacutely dosed with 100 milligrams per kilogram of ({sup 14}C)-TNT. These studies show that the TNT-related compounds of concern do accumulate in muscle and liver tissue of the mouse under the experimental conditions imposed, but at concentrations below the 1.2 ppM level. However, products other than TNT and free metabolites may be accumulating since some ({sup 14}C) was found to be nonextractable. 13 refs., 5 figs., 6 tabs.

  5. Photoacoustic characterization of ovarian tissue

    NASA Astrophysics Data System (ADS)

    Aguirre, Andres; Gamelin, John; Guo, Puyun; Yan, Shikui; Sanders, Mary; Brewer, Molly; Zhu, Quing

    2009-02-01

    Ovarian cancer has the highest mortality of all gynecologic cancers with a five-year survival rate of only 30%. Because current imaging techniques (ultrasound, CT, MRI, PET) are not capable of detecting ovarian cancer early, most diagnoses occur in later stages (III/IV). Thus many women are not correctly diagnosed until the cancer becomes widely metastatic. On the other hand, while the majority of women with a detectable ultrasound abnormality do not harbor a cancer, they all undergo unnecessary oophorectomy. Hence, new imaging techniques that can provide functional and molecular contrasts are needed for improving the specificity of ovarian cancer detection and characterization. One such technique is photoacoustic imaging, which has great potential to reveal early tumor angiogenesis through intrinsic optical absorption contrast from hemoglobin or extrinsic contrast from conjugated agents binding to appropriate molecular receptors. To better understand the cancer disease process of ovarian tissue using photoacoustic imaging, it is necessary to first characterize the properties of normal ovarian tissue. We have imaged ex-vivo ovarian tissue using a 3D co-registered ultrasound and photoacoustic imaging system. The system is capable of volumetric imaging by means of electronic focusing. Detecting and visualizing small features from multiple viewing angles is possible without the need for any mechanical movement. The results show strong optical absorption from vasculature, especially highly vascularized corpora lutea, and low absorption from follicles. We will present correlation of photoacoustic images from animals with histology. Potential application of this technology would be the noninvasive imaging of the ovaries for screening or diagnostic purposes.

  6. Quality control in tissue banking--ensuring the safety of allograft tissues.

    PubMed

    Humphries, Linda K; Mansavage, Vicki L

    2006-09-01

    DESPITE FEDERAL REGULATIONS for tissue-banking practices, inadequate quality control led to the largest allograft tissue recall in history in October 2005. THE RECALL INCLUDED all allograft tissues obtained from 761 donors and distributed by five tissue banks. Many of these tissues already had been implanted and were unrecoverable. THIS ARTICLE DESCRIBES the many tissue-banking industry variables, including donor selection and testing and tissue recovery, processing, and preservation. QUESTIONS THAT HEALTH CARE providers can ask to determine which tissue banks' quality control measures best ensure the safety of the allografts they provide also are included. PMID:17004664

  7. [Radiotherapy of adult soft tissue sarcoma].

    PubMed

    Le Péchoux, C; Moureau-Zabotto, L; Llacer, C; Ducassou, A; Sargos, P; Sunyach, M P; Thariat, J

    2016-09-01

    Incidence of soft tissue sarcoma is low and requires multidisciplinary treatment in specialized centers. The objective of this paper is to report the state of the art regarding indications and treatment techniques of main soft tissue sarcoma localisations.

  8. Method for localizing heating in tumor tissue

    DOEpatents

    Doss, James D.; McCabe, Charles W.

    1977-04-12

    A method for a localized tissue heating of tumors is disclosed. Localized radio frequency current fields are produced with specific electrode configurations. Several electrode configurations are disclosed, enabling variations in electrical and thermal properties of tissues to be exploited.

  9. General Information about Adult Soft Tissue Sarcoma

    MedlinePlus

    ... Soft Tissue Sarcoma Treatment (PDQ®)–Patient Version General Information About Adult Soft Tissue Sarcoma Go to Health ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  10. General Information about Childhood Soft Tissue Sarcoma

    MedlinePlus

    ... Soft Tissue Sarcoma Treatment (PDQ®)–Patient Version General Information About Childhood Soft Tissue Sarcoma Go to Health ... the PDQ Pediatric Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  11. Childhood Soft Tissue Sarcoma: Treatment Information

    MedlinePlus

    ... Germ Cell Tumors Kidney/Wilms Tumor Liver Cancer Neuroblastoma Osteosarcoma Rhabdomyosarcoma Skin Cancer Soft Tissue Sarcoma Thyroid ... Tumor Liver Cancer Lymphoma (Non-Hodgkin) Lymphoma (Hodgkin) Neuroblastoma Osteosarcoma Retinoblastoma Rhabdomyosarcoma Skin Cancer Soft Tissue Sarcoma ...

  12. Quantification of adipose tissue insulin sensitivity.

    PubMed

    Søndergaard, Esben; Jensen, Michael D

    2016-06-01

    In metabolically healthy humans, adipose tissue is exquisitely sensitive to insulin. Similar to muscle and liver, adipose tissue lipolysis is insulin resistant in adults with central obesity and type 2 diabetes. Perhaps uniquely, however, insulin resistance in adipose tissue may directly contribute to development of insulin resistance in muscle and liver because of the increased delivery of free fatty acids to those tissues. It has been hypothesized that insulin adipose tissue resistance may precede other metabolic defects in obesity and type 2 diabetes. Therefore, precise and reproducible quantification of adipose tissue insulin sensitivity, in vivo, in humans, is an important measure. Unfortunately, no consensus exists on how to determine adipose tissue insulin sensitivity. We review the methods available to quantitate adipose tissue insulin sensitivity and will discuss their strengths and weaknesses.

  13. 3D Printing for Tissue Engineering

    PubMed Central

    Jia, Jia; Yao, Hai; Mei, Ying

    2016-01-01

    Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host tissue integration (e.g., cellular infiltration, vascularization, and active remodeling). This review will cover several approaches that have advanced the field of 3D printing through novel fabrication methods of tissue engineering constructs. It will also discuss the applications of synthetic and natural materials for 3D printing facilitated tissue fabrication. PMID:26869728

  14. Biomimetic strategies for engineering composite tissues.

    PubMed

    Lee, Nancy; Robinson, Jennifer; Lu, Helen

    2016-08-01

    The formation of multiple tissue types and their integration into composite tissue units presents a frontier challenge in regenerative engineering. Tissue-tissue synchrony is crucial in providing structural support for internal organs and enabling daily activities. This review highlights the state-of-the-art in composite tissue scaffold design, and explores how biomimicry can be strategically applied to avoid over-engineering the scaffold. Given the complexity of biological tissues, determining the most relevant parameters for recapitulating native structure-function relationships through strategic biomimicry will reduce the burden for clinical translation. It is anticipated that these exciting efforts in composite tissue engineering will enable integrative and functional repair of common soft tissue injuries and lay the foundation for total joint or limb regeneration.

  15. 21 CFR 878.4010 - Tissue adhesive.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4010 Tissue adhesive. (a) Tissue... intended for use in the embolization of brain arteriovenous malformation or for use in ophthalmic...

  16. 21 CFR 878.4010 - Tissue adhesive.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4010 Tissue adhesive. (a) Tissue... intended for use in the embolization of brain arteriovenous malformation or for use in ophthalmic...

  17. 21 CFR 878.4010 - Tissue adhesive.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4010 Tissue adhesive. (a) Tissue... intended for use in the embolization of brain arteriovenous malformation or for use in ophthalmic...

  18. 21 CFR 878.4010 - Tissue adhesive.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4010 Tissue adhesive. (a) Tissue... intended for use in the embolization of brain arteriovenous malformation or for use in ophthalmic...

  19. 21 CFR 878.4010 - Tissue adhesive.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4010 Tissue adhesive. (a) Tissue... intended for use in the embolization of brain arteriovenous malformation or for use in ophthalmic...

  20. Soft tissue differentiation by diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Zam, Azhar; Stelzle, Florian; Nkenke, Emeka; Tangermann-Gerk, Katja; Schmidt, Michael; Adler, Werner; Douplik, Alexandre

    2009-07-01

    Laser surgery gives the possibility to work remotely which leads to high precision, little trauma and high level sterility. However these advantages are coming with the lack of haptic feedback during the laser ablation of tissue. Therefore additional means are required to control tissue-specific ablation during laser surgery supporting the surgeon regardless of experience and skills. Diffuse Reflectance Spectroscopy provides a straightforward and simple approach for optical tissue differentiation. We measured diffuse reflectance from four various tissue types ex vivo. We applied Linear Discriminant Analysis (LDA) to differentiate the four tissue types and computed the area under the ROC curve (AUC). Special emphasis was taken on the identification of nerve as the most crucial tissue for maxillofacial surgery. The results show a promise for differentiating soft tissues as guidance for tissue-specific laser surgery by means of the diffuse reflectance.

  1. [Radiotherapy of adult soft tissue sarcoma].

    PubMed

    Le Péchoux, C; Moureau-Zabotto, L; Llacer, C; Ducassou, A; Sargos, P; Sunyach, M P; Thariat, J

    2016-09-01

    Incidence of soft tissue sarcoma is low and requires multidisciplinary treatment in specialized centers. The objective of this paper is to report the state of the art regarding indications and treatment techniques of main soft tissue sarcoma localisations. PMID:27523415

  2. Organ printing: tissue spheroids as building blocks.

    PubMed

    Mironov, Vladimir; Visconti, Richard P; Kasyanov, Vladimir; Forgacs, Gabor; Drake, Christopher J; Markwald, Roger R

    2009-04-01

    Organ printing can be defined as layer-by-layer additive robotic biofabrication of three-dimensional functional living macrotissues and organ constructs using tissue spheroids as building blocks. The microtissues and tissue spheroids are living materials with certain measurable, evolving and potentially controllable composition, material and biological properties. Closely placed tissue spheroids undergo tissue fusion - a process that represents a fundamental biological and biophysical principle of developmental biology-inspired directed tissue self-assembly. It is possible to engineer small segments of an intraorgan branched vascular tree by using solid and lumenized vascular tissue spheroids. Organ printing could dramatically enhance and transform the field of tissue engineering by enabling large-scale industrial robotic biofabrication of living human organ constructs with "built-in" perfusable intraorgan branched vascular tree. Thus, organ printing is a new emerging enabling technology paradigm which represents a developmental biology-inspired alternative to classic biodegradable solid scaffold-based approaches in tissue engineering.

  3. Soft tissue engineering in craniomaxillofacial surgery

    PubMed Central

    Kim, Roderick Y; Fasi, Anthony C; Feinberg, Stephen E

    2014-01-01

    Craniofacial soft tissue reconstruction may be required following trauma, tumor resection, and to repair congenital deformities. Recent advances in the field of tissue engineering have significantly widened the reconstructive armamentarium of the surgeon. The successful identification and combination of tissue engineering, scaffold, progenitor cells, and physiologic signaling molecules has enabled the surgeon to design, recreate the missing tissue in its near natural form. This has resolved the issues like graft rejection, wound dehiscence, or poor vascularity. Successfully reconstructed tissue through soft tissue engineering protocols would help surgeon to restore the form and function of the lost tissue in its originality. This manuscript intends to provide a glimpse of the basic principle of tissue engineering, contemporary, and future direction of this field as applied to craniofacial surgery. PMID:24987591

  4. Right Ventricular Tissue Doppler in Space Flight

    NASA Technical Reports Server (NTRS)

    Garcia, Kathleen M.; Hamilton, Douglas R.; Sargsyan, Ashot E.; Ebert, Douglas; Martin, David S.; Barratt, Michael R.; Martin, David S.; Bogomolov, Valery V.; Dulchavsky, Scott A.; Duncan, J. Michael

    2010-01-01

    The presentation slides review normal physiology of the right ventricle in space, general physiology of the right ventricle; difficulties in imaging the heart in space, imaging methods, tissue Doppler spectrum, right ventricle tissue Doppler, and Rt Tei Index.

  5. Biomimetic strategies for engineering composite tissues.

    PubMed

    Lee, Nancy; Robinson, Jennifer; Lu, Helen

    2016-08-01

    The formation of multiple tissue types and their integration into composite tissue units presents a frontier challenge in regenerative engineering. Tissue-tissue synchrony is crucial in providing structural support for internal organs and enabling daily activities. This review highlights the state-of-the-art in composite tissue scaffold design, and explores how biomimicry can be strategically applied to avoid over-engineering the scaffold. Given the complexity of biological tissues, determining the most relevant parameters for recapitulating native structure-function relationships through strategic biomimicry will reduce the burden for clinical translation. It is anticipated that these exciting efforts in composite tissue engineering will enable integrative and functional repair of common soft tissue injuries and lay the foundation for total joint or limb regeneration. PMID:27010653

  6. Applicator for cyanoacrylate tissue adhesive.

    PubMed

    Wessels, I F; McNeill, J I

    1989-03-01

    Cyanoacrylate tissue adhesive (CTA) is very useful for emergency treatment of corneal perforations. Lack of Food and Drug Administration approval as well as concerns about toxicity from the application of large amounts of glue, however, have limited its use. It is difficult to apply a sufficiently small amount of glue or to achieve a water tight seal using published techniques of glue application. We have found a commercially available micropipette (used in dental work) to be more effective than other methods of CTA application. With this apparatus, precise and accurate placement of minimal amounts of CTA at the slit lamp is consistently possible.

  7. Sex differences in adipose tissue

    PubMed Central

    Fuente-Martín, Esther; Argente-Arizón, Pilar; Ros, Purificación; Argente, Jesús; Chowen, Julie A

    2013-01-01

    Obesity and its associated secondary complications are active areas of investigation in search of effective treatments. As a result of this intensified research numerous differences between males and females at all levels of metabolic control have come to the forefront. These differences include not only the amount and distribution of adipose tissue, but also differences in its metabolic capacity and functions between the sexes. Here, we review some of the recent advances in our understanding of these dimorphisms and emphasize the fact that these differences between males and females must be taken into consideration in hopes of obtaining successful treatments for both sexes. PMID:23991358

  8. Undulation Instability of Epithelial Tissues

    NASA Astrophysics Data System (ADS)

    Basan, Markus; Joanny, Jean-François; Prost, Jacques; Risler, Thomas

    2011-04-01

    Treating the epithelium as an incompressible fluid adjacent to a viscoelastic stroma, we find a novel hydrodynamic instability that leads to the formation of protrusions of the epithelium into the stroma. This instability is a candidate for epithelial fingering observed in vivo. It occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Our work provides physical insight into a potential mechanism by which interfaces between epithelia and stromas undulate and potentially by which tissue dysplasia leads to cancerous invasion.

  9. Tissue enzyme studies in Macaca nemestrina monkeys.

    NASA Technical Reports Server (NTRS)

    Hubbard, R. W.; Hoffman, R. A.; Jenkins, D.

    1971-01-01

    Total enzyme activities in fresh tissue specimens from major organs of Macaca nemestrina were analyzed for lactic dehydrogenase (LDH), creatine phosphokinase (CPK), and aldolase. The concentration of these enzymes varied among the different tissue with skeletal muscle, heart, and brain having the highest activities. LDH isozymes determinations for the various tissues were also made. The spectrum of LDH isozyme distribution appears to be quite specific and characteristic for at least some of the tissues analyzed.

  10. Fatty acids of Pinus elliottii tissues.

    NASA Technical Reports Server (NTRS)

    Laseter, J. L.; Lawler, G. C.; Walkinshaw, C. H.; Weete, J. D.

    1973-01-01

    The total fatty constituents of slash pine (Pinus elliottii) tissue cultures, seeds, and seedlings were examined by GLC and MS. Qualitatively, the fatty acid composition of these tissues was found to be very similar to that reported for other pine species. The fatty acid contents of the tissue cultures resembled that of the seedling tissues. The branched-chain C(sub 17) acid reported for several other Pinus species was confirmed as the anteiso isomer.

  11. Laser Ablatin of Dental Hard Tissue

    SciTech Connect

    Seka, W.; Rechmann, P.; Featherstone, J.D.B.; Fried, D.

    2007-07-31

    This paper discusses ablation of dental hard tissue using pulsed lasers. It focuses particularly on the relevant tissue and laser parameters and some of the basic ablation processes that are likely to occur. The importance of interstitial water and its phase transitions is discussed in some detail along with the ablation processes that may or may not directly involve water. The interplay between tissue parameters and laser parameters in the outcome of the removal of dental hard tissue is discussed in detail.

  12. Comparative Histology of Plasma Treated Tissue

    NASA Astrophysics Data System (ADS)

    Rick, Kyle

    2009-10-01

    Atmospheric plasmas applied in surgical settings have unique characteristics found in histological results from animal tissue studies. This is evident in both ex vivo bench tissue tests and in vivo fresh tissue. Examples of these histological features are presented as results of a comparative study between plasma treated, common medical argon coagulation, and electrosurgery.

  13. Tissue Barriers: Introducing an exciting new journal

    PubMed Central

    Ivanov, Andrei I

    2014-01-01

    This Editorial is written to introduce Tissue Barriers, a new Taylor & Francis journal, to the readers of Temperature. It describes the role of temperature in the regulation of different tissue barriers under normal and disease conditions. It also highlights the most interesting articles published in the first volume of Tissue Barriers.

  14. Hard-Soft Tissue Interface Engineering.

    PubMed

    Armitage, Oliver E; Oyen, Michelle L

    2015-01-01

    The musculoskeletal system is comprised of three distinct tissue categories: structural mineralized tissues, actuating muscular soft tissues, and connective tissues. Where connective tissues - ligament, tendon and cartilage - meet with bones, a graded interface in mechanical properties occurs that allows the transmission of load without creating stress concentrations that would cause tissue damage. This interface typically occurs over less than 1 mm and contains a three order of magnitude difference in elastic stiffness, in addition to changes in cell type and growth factor concentrations among others. Like all engineered tissues, the replication of these interfaces requires the production of scaffolds that will provide chemical and mechanical cues, resulting in biologically accurate cellular differentiation. For interface tissues however, the scaffold must provide spatially graded chemical and mechanical cues over sub millimetre length scales. Naturally, this complicates the manufacture of the scaffolds and every stage of their subsequent cell seeding and growth, as each region has different optimal conditions. Given the higher degree of difficulty associated with replicating interface tissues compared to surrounding homogeneous tissues, it is likely that the development of complex musculoskeletal tissue systems will continue to be limited by the engineering of connective tissues interfaces with bone.

  15. Leaf hydraulics II: vascularized tissues.

    PubMed

    Rockwell, Fulton E; Holbrook, N Michele; Stroock, Abraham D

    2014-01-01

    Current models of leaf hydration employ an Ohm's law analogy of the leaf as an ideal capacitor, neglecting the resistance to flow between cells, or treat the leaf as a plane sheet with a source of water at fixed potential filling the mid-plane, neglecting the discrete placement of veins as well as their resistance. We develop a model of leaf hydration that considers the average conductance of the vascular network to a representative areole (region bounded by the vascular network), and represent the volume of tissue within the areole as a poroelastic composite of cells and air spaces. Solutions to the 3D flow problem are found by numerical simulation, and these results are then compared to 1D models with exact solutions for a range of leaf geometries, based on a survey of temperate woody plants. We then show that the hydration times given by these solutions are well approximated by a sum of the ideal capacitor and plane sheet times, representing the time for transport through the vasculature and tissue respectively. We then develop scaling factors relating this approximate solution to the 3D model, and examine the dependence of these scaling factors on leaf geometry. Finally, we apply a similar strategy to reduce the dimensions of the steady state problem, in the context of peristomatal transpiration, and consider the relation of transpirational gradients to equilibrium leaf water potential measurements.

  16. Paracrine regulation of endometriotic tissue.

    PubMed

    Minici, Francesca; Tiberi, Federica; Tropea, Anna; Miceli, Fiorella; Fiorella, Miceli; Orlando, Mariateresa; Gangale, Maria Francesca; Romani, Federica; Catino, Stefania; Campo, Sebastiano; Lanzone, Antonio; Apa, Rosanna

    2007-10-01

    Endometriosis is a chronic estrogen-dependent gynecological disease, characterized by pelvic pain and infertility, defined as the presence of endometrial glands and stroma within the pelvic peritoneum and other extrauterine sites. In the peritoneal cavity endometrial cells adhere, proliferate and induce an inflammatory response. Despite a long history of clinical and experimental research, the pathogenesis of endometriosis is still controversial. Abnormal immunological activation, the endocrine milieu and the peritoneal environment all dramatically affect endometriotic tissue function. Recent studies suggest that the peritoneal fluid of women with endometriosis contains an increased number of activated macrophages and other immune cells that secrete various local products, such as growth factors and cytokines, which exert a paracrine action on endometriotic cells. Since the peculiar biological characteristics of eutopic endometrium from women with endometriosis differ from endometrium of normal subjects, an important role in the pathogenesis of this complex disease has been suggested. All of these factors contribute to enhanced proliferative and angiogenic activity and a number of functional and structural changes, resulting in the particular behavior of this tissue.

  17. Polyelectrolyte Multilayers in Tissue Engineering

    PubMed Central

    Detzel, Christopher J.; Larkin, Adam L.

    2011-01-01

    The layer-by-layer assembly of sequentially adsorbed, alternating polyelectrolytes has become increasingly important over the past two decades. The ease and versatility in assembling polyelectrolyte multilayers (PEMs) has resulted in numerous wide ranging applications of these materials. More recently, PEMs are being used in biological applications ranging from biomaterials, tissue engineering, regenerative medicine, and drug delivery. The ability to manipulate the chemical, physical, surface, and topographical properties of these multilayer architectures by simply changing the pH, ionic strength, thickness, and postassembly modifications render them highly suitable to probe the effects of external stimuli on cellular responsiveness. In the field of regenerative medicine, the ability to sequester growth factors and to tether peptides to PEMs has been exploited to direct the lineage of progenitor cells and to subsequently maintain a desired phenotype. Additional novel applications include the use of PEMs in the assembly of three-dimensional layered architectures and as coatings for individual cells to deliver tunable payloads of drugs or bioactive molecules. This review focuses on literature related to the modulation of chemical and physical properties of PEMs for tissue engineering applications and recent research efforts in maintaining and directing cellular phenotype in stem cell differentiation. PMID:21210759

  18. Tissue engineering of blood vessel

    PubMed Central

    Zhang, Wen Jie; Liu, Wei; Cui, Lei; Cao, Yilin

    2007-01-01

    Abstract Vascular grafts are in large demand for coronary and peripheral bypass surgeries. Although synthetic grafts have been developed, replacement of vessels with purely synthetic polymeric conduits often leads to the failure of such graft, especially in the grafts less than 6 mm in diameter or in the areas of low blood flow, mainly due to the early formation of thrombosis. Moreover, the commonly used materials lack growth potential, and long-term results have revealed several material-related failures, such as stenosis, thromboembolization, calcium deposition and infection. Tissue engineering has become a promising approach for generating a bio-compatible vessel graft with growth potential. Since the first success of constructing blood vessels with collagen and cultured vascular cells by Weinberg and Bell, there has been considerable progress in the area of vessel engineering. To date, tissue- engineered blood vessels (TEBVs) could be successfully constructed in vitro, and be used to repair the vascular defects in animal models. This review describes the major progress in the field, including the seeding cell sources, the biodegradable scaffolds, the construction technologies, as well as the encouraging achievements in clinical applications. The remaining challenges are also discussed. PMID:17979876

  19. Cellular Functions of Tissue Transglutaminase

    PubMed Central

    Nurminskaya, Maria V.; Belkin, Alexey M.

    2013-01-01

    Transglutaminase 2 (TG2 or tissue transglutaminase) is a highly complex multifunctional protein that acts as transglutaminase, GTPase/ATPase, protein disulfide isomerase, and protein kinase. Moreover, TG2 has many well-documented nonenzymatic functions that are based on its noncovalent interactions with multiple cellular proteins. A vast array of biochemical activities of TG2 accounts for its involvement in a variety of cellular processes, including adhesion, migration, growth, survival, apoptosis, differentiation, and extracellular matrix organization. In turn, the impact of TG2 on these processes implicates this protein in various physiological responses and pathological states, contributing to wound healing, inflammation, autoimmunity, neurodegeneration, vascular remodeling, tumor growth and metastasis, and tissue fibrosis. TG2 is ubiquitously expressed and is particularly abundant in endothelial cells, fibroblasts, osteoblasts, monocytes/macrophages, and smooth muscle cells. The protein is localized in multiple cellular compartments, including the nucleus, cytosol, mitochondria, endolysosomes, plasma membrane, and cell surface and extracellular matrix, where Ca2+, nucleotides, nitric oxide, reactive oxygen species, membrane lipids, and distinct protein–protein interactions in the local microenvironment jointly regulate its activities. In this review, we discuss the complex biochemical activities and molecular interactions of TG2 in the context of diverse subcellular compartments and evaluate its wide ranging and cell type-specific biological functions and their regulation. PMID:22364871

  20. Infrared Microspectroscopy Of Pathologic Tissue

    NASA Astrophysics Data System (ADS)

    O'Leary, Timothy J.; Engler, Walter F.; Ventre, Kathleen M.

    1989-12-01

    Infrared spectroscopy is a powerful technique by which to characterize the conformations of proteins, lipids, and nucleic acids (1). Previously we have demonstrated that infrared spectroscopy can be used to characterize the secondary structure of abnormal protein accumulation products, known as amyloid, which are often found in association with medullary carcinoma of the thyroid (2). The utility of the technique was highly limited by the fact that essentially the entire specimen had to consist of this abnormal protein for infrared spectroscopic analysis to be useful. The development of high quality microscopes capable of both light microscopic and infrared characterization of materials has enabled us to extend our earlier use of infrared spectroscopy to diseases and tissues in which the abnormal region of interest is only a few hundred square micrometers in area. Tissue for spectroscopic examination is mounted on microscope slides which have been prepared by acid washing, plating with gold or gold-palladium alloy (3) and coating with high molecular weight poly-L-lysine. Sections of tissue which have been previously embedded in paraffin are cut with a microtome at 4 to 5 micrometers thickness, floated onto a bath of distilled water, picked up on the microscope slide, and allowed to dry overnight. Paraffin is removed by soaking the slides in two changes of xylene, and then the sections are rehydrated by placing them in absolute alcohol, then in fifty percent alcohol, and finally in water. Sections may then be stained using standard histologic stains, such as hematoxylin and eosin, then once again dehydrated with alcohol. After drying, the sections are covered with an index-matching fluid, such as Fluorolube, which allows a relatively good visual microscopic examination of the tissue when the microscope is used in reflectance mode. High quality reflectance infrared spectra may be easily obtained when the tissue is prepared and mounted in this way (Figure 1

  1. Hardwiring Stem Cell Communication through Tissue Structure.

    PubMed

    Xin, Tianchi; Greco, Valentina; Myung, Peggy

    2016-03-10

    Adult stem cells across diverse organs self-renew and differentiate to maintain tissue homeostasis. How stem cells receive input to preserve tissue structure and function largely relies on their communication with surrounding cellular and non-cellular elements. As such, how tissues are organized and patterned not only reflects organ function, but also inherently hardwires networks of communication between stem cells and their environment to direct tissue homeostasis and injury repair. This review highlights how different methods of stem cell communication reflect the unique organization and function of diverse tissues. PMID:26967287

  2. Hardwiring Stem Cell Communication through Tissue Structure.

    PubMed

    Xin, Tianchi; Greco, Valentina; Myung, Peggy

    2016-03-10

    Adult stem cells across diverse organs self-renew and differentiate to maintain tissue homeostasis. How stem cells receive input to preserve tissue structure and function largely relies on their communication with surrounding cellular and non-cellular elements. As such, how tissues are organized and patterned not only reflects organ function, but also inherently hardwires networks of communication between stem cells and their environment to direct tissue homeostasis and injury repair. This review highlights how different methods of stem cell communication reflect the unique organization and function of diverse tissues.

  3. Impairment of granulation tissue formation after menopause.

    PubMed

    Gniadecki, R; Wyrwas, B; Kabala, A; Matecka, J

    1996-04-01

    Formation of connective tissue is an essential step in the process of wound healing. After menopause an atrophy of connective tissues in skin, bone, and reproductive organs takes place. Using a dead-space wound healing model we measured collagen synthesis and deposition, and cell replication in the granulation tissue of 18 premenopausal and 23 peri- and postmenopausal women not receiving any hormonal therapy. In the postmenopausal group collagen synthesis and deposition and cell number in the granulation tissue were diminished. These results document the impairment of the granulation tissue formation after menopause.

  4. Optical metabolic imaging of live tissue cultures

    NASA Astrophysics Data System (ADS)

    Walsh, Alex J.; Cook, Rebecca S.; Arteaga, Carlos L.; Skala, Melissa C.

    2013-02-01

    The fluorescence properties, both intensity and fluorescence lifetime, of NADH and FAD, two coenzymes of metabolism, are sensitive, high resolution measures of cellular metabolism. However, often in vivo measurements of tissue are not feasible. In this study, we investigate the stability over time of two-photon auto-fluorescence imaging of NADH and FAD in live-cultured tissues. Our results demonstrate that cultured tissues remain viable for at least several days post excision. Furthermore, the optical redox ratio, NADH fluorescence lifetime, and FAD fluorescence lifetime do not significantly change in the cultured tissues over time. With these findings, we demonstrate the potential of sustained tissue culture techniques for optical metabolic imaging.

  5. Bioengineering heart tissue for in vitro testing

    PubMed Central

    Cimetta, Elisa; Godier-Furnémont, Amandine; Vunjak-Novakovic, Gordana

    2013-01-01

    A classical paradigm of tissue engineering is to grow tissues for implantation by using human stem cells in conjunction with biomaterial scaffolds (templates for tissue formation) and bioreactors (culture systems providing environmental control). A reverse paradigm is now emerging through microphysiological platforms for preclinical testing of drugs and modeling of disease that contain large numbers of very small human tissues. We discuss the biomimetic approach as a common underlying principle and some of the specifics related to the design and utilization of platforms with heart micro-tissues for high-throughput screening in vitro. PMID:23932513

  6. Electromechanical Properties of Bone Tissue.

    NASA Astrophysics Data System (ADS)

    Regimbal, Raymond L.

    Discrepancies between calculated and empirical properties of bone are thought to be due to a general lack of consideration for the extent and manner(s) with which bone components interact at the molecular level. For a bone component in physiological fluid or whenever two phases are in contact, there is a region between the bulk phases called the electrical double layer which is marked by a separation of electric charges. For the purpose of studying electrical double layer interactions, the method of particle microelectrophoresis was used to characterize bone and its major constituents on the basis of the net charge they bear when suspended in ionic media of physiological relevance. With the data presented as pH versus zeta (zeta ) potential, the figures reveal an isoelectric point (IEP) for bone mineral near pH 8.6, whereas intact and EDTA demineralized bone tissue both exhibit IEPs near pH 5.1. While these data demonstrate the potential for a significant degree of coulombic interaction between the bone mineral and organic constituent double layers, it was also observed that use of inorganic phosphate buffers, as a specific marker for bone mineral, resulted in (1) an immediate reversal, from positive to negative, of the bone mineral zeta potential (2) rendered the zeta potential of intact bone more negative in a manner linearly dependent on both time and temperature and (3) had no affect on demineralized bone (P < 0.01). In agreement with that shown in model protein-hydroxyapatite systems, it is suggested here that inorganic phosphate ions in solution compete with organic acid groups (e.g. carboxyl and phosphate of collagen, sialoprotein, ...) for positively charged sites on the bone mineral surface and effectively uncouple the bone mineral and organic phase double layers. Mechanically, this uncoupling is manifested as a loss of tissue rigidity when monitoring the midspan deflection of bone beams subject to constant load for a 3 day period. While it is thus

  7. Human Postmortem Tissue: What Quality Markers Matter?

    PubMed Central

    Stan, Ana D.; Ghose, Subroto; Gao, Xue-Min; Roberts, Rosalinda C.; Lewis-Amezcua, Kelly; Hatanpaa, Kimmo J.; Tamminga, Carol A.

    2007-01-01

    Post mortem human brain tissue is used for the study of many different brain diseases. A key factor in conducting postmortem research is the quality of the tissue. Unlike animal tissue, whose condition at death can be controlled and influenced, human tissue can only be collected naturalistically. This introduces potential confounds, based both on pre- and postmortem conditions, that may influence the quality of tissue and its ability to yield accurate results. The traditionally recognized confounds that reduce tissue quality are agonal factors (e.g., coma, hypoxia, hyperpyrexia at the time of death), and long postmortem interval (PMI). We measured tissue quality parameters in over 100 postmortem cases collected from different sources and correlated them with RNA quality (as indicated by the RNA Integrity Number (RIN)) and with protein quality (as measured by the level of representative proteins). Our results show that the most sensible indicator of tissue quality is RIN and that there is a good correlation between RIN and the pH. No correlation developed between protein levels and the aforementioned factors. Moreover, even when RNA was degraded, the protein levels remained stable. However, these correlations did not prove true under all circumstances (e.g. thawed tissue, surgical tissue), that yielded unexpected quality indicators. These data also suggest that cases whose source was a Medical Examiner’s office represent high tissue quality. PMID:17045977

  8. Tissue simulating gel for medical research

    NASA Technical Reports Server (NTRS)

    Companion, John A. (Inventor)

    1991-01-01

    A tissue simulating gel and a method for preparing the tissue simulating gel are disclosed. The tissue simulating gel is prepared by a process using water, gelatin, ethylene glycol, and a cross-linking agent. In order to closely approximate the characteristics of the type of tissue being simulated, other material has been added to change the electrical, sound conducting, and wave scattering properties of the tissue simulating gel. The result of the entire process is a formulation that will not melt at the elevated temperatures involved in hyperthermia medical research. Furthermore, the tissue simulating gel will not support mold or bacterial growth, is of a sufficient mechanical strength to maintain a desired shape without a supporting shell, and is non-hardening and non-drying. Substances have been injected into the tissue simulating gel prior to the setting-up thereof just as they could be injected into actual tissue, and the tissue simulating gel is translucent so as to permit visual inspection of its interior. A polyurethane spray often used for coating circuit boards can be applied to the surface of the tissue simulating gel to give a texture similar to human skin, making the tissue simulating gel easier to handle and contributing to its longevity.

  9. Radiotherapy in patients with connective tissue diseases.

    PubMed

    Giaj-Levra, Niccolò; Sciascia, Savino; Fiorentino, Alba; Fersino, Sergio; Mazzola, Rosario; Ricchetti, Francesco; Roccatello, Dario; Alongi, Filippo

    2016-03-01

    The decision to offer radiotherapy in patients with connective tissue diseases continues to be challenging. Radiotherapy might trigger the onset of connective tissue diseases by increasing the expression of self-antigens, diminishing regulatory T-cell activity, and activating effectors of innate immunity (dendritic cells) through Toll-like receptor-dependent mechanisms, all of which could potentially lead to breaks of immune tolerance. This potential risk has raised some debate among radiation oncologists about whether patients with connective tissue diseases can tolerate radiation as well as people without connective tissue diseases. Because the number of patients with cancer and connective tissue diseases needing radiotherapy will probably increase due to improvements in medical treatment and longer life expectancy, the issue of interactions between radiotherapy and connective tissue diseases needs to be clearer. In this Review, we discuss available data and evidence for patients with connective tissue diseases treated with radiotherapy.

  10. Thermomechanical analysis of soft-tissue thermotherapy.

    PubMed

    Aksan, Alptekin; McGrath, John J

    2003-10-01

    Soft-tissue thermotherapy based on sub-ablative heating of collagenous tissues finds wide-spread application in medicine such as tissue welding, thermokeratoplasty, skin resurfacing, elimination of discogenic pain in the spine and treatment of joint instability. In this paper, heat-induced thermomechanical response characteristics of collagenous tissues are quantified by means of in vitro experimentation with a representative model tissue (New Zealand white rabbit patellar tendon). Three distinct heat-induced thermomechanical response regimes (defined by the rate of deformation and the variation of material properties) are identified. Arrhenius damage integral representation of collagenous tissue thermal history is shown to be adequate in establishing the master response curves for quantification of thermomechanical response for modeling purposes. The trade-off between the improved kinematical stability and compromised mechanical stability of the heated collagenous tissue is shown to be the major challenge hindering the success of subablative thermotherapies.

  11. Physics of ultrasonic surgery using tissue fragmentation.

    PubMed

    Bond, L J; Cimino, W W

    1996-06-01

    The ultrasonic surgical aspirator employs a vibrating metal tip to fragment tissue and then aspirates the debris through the hollow center of the tip. The mechanism of interaction has been stated to be poorly understood, most likely related to cavitation, possibly acting in concert with other mechanical actions. The role of stroke, suction, frequency, tissue type, and tip area have been examined with regard to tissue fragmentation rate. Suction is shown to make a significant contribution to the interaction. Photographic and acoustic data from experiments in water and on a range of fresh pig tissues are used to investigate the fragmentation effect. A model for the primary mechanism for tissue fragmentation is presented. This involves the horn-tip impact and other mechanical forces, operating in combination with hydrodynamic forces applied to the tissue on the forward stroke in each cycle. No evidence of cavitation in tissue was observed.

  12. The role of bioreactors in tissue engineering.

    PubMed

    Martin, Ivan; Wendt, David; Heberer, Michael

    2004-02-01

    Ex vivo engineering of living tissues is a rapidly developing area with the potential to impact significantly on a wide-range of biomedical applications. Major obstacles to the generation of functional tissues and their widespread clinical use are related to a limited understanding of the regulatory role of specific physicochemical culture parameters on tissue development, and the high manufacturing costs of the few commercially available engineered tissue products. By enabling reproducible and controlled changes of specific environmental factors, bioreactor systems provide both the technological means to reveal fundamental mechanisms of cell function in a 3D environment, and the potential to improve the quality of engineered tissues. In addition, by automating and standardizing tissue manufacture in controlled closed systems, bioreactors could reduce production costs, thus facilitating a wider use of engineered tissues.

  13. Tissue engineering strategies for bone regeneration.

    PubMed

    Mistry, Amit S; Mikos, Antonios G

    2005-01-01

    Bone loss due to trauma or disease is an increasingly serious health problem. Current clinical treatments for critical-sized defects are problematic and often yield poor healing due to the complicated anatomy and physiology of bone tissue, as well as the limitations of medical technology. Bone tissue engineering offers a promising alternative strategy of healing severe bone injuries by utilizing the body's natural biological response to tissue damage in conjunction with engineering principles. Osteogenic cells, growth factors, and biomaterial scaffolds form the foundation of the many bone tissue engineering strategies employed to achieve repair and restoration of damaged tissue. An ideal biomaterial scaffold will provide mechanical support to an injured site and also deliver growth factors and cells into a defect to encourage tissue growth. Additionally, this biomaterial should degrade in a controlled manner without causing a significant inflammatory response. The following chapter highlights multiple strategies and the most recent advances in various areas of research for bone tissue regeneration.

  14. [Regeneration and fibrosis of corneal tissues].

    PubMed

    Simirskiĭ, V N

    2014-01-01

    In this review, the features of the regeneration of corneal tissue and its disorders leading to the development of fibrosis are considered. The data on the presence of stem (clonogenic) cell pool in the corneal tissues (epithelium, endothelium, stroma) are given; these cells can serve as a source for regeneration of the tissues at injury or various diseases. The main steps of regeneration of corneal tissues and their disorders that lead to outstripping proliferation of myofibroblasts and secretion of extracellular matrix in the wound area and eventually cause the formation of connective tissue scar and corneal opacity are considered. Particular attention is given to the successes of translational medicine in the treatment of corneal tissue fibrosis. The methods of cell therapy aimed at the restoration of stem cell pool of corneal tissues are the most promising. Gene therapy provides more opportunities; one of its main objectives is the suppression of the myofibroblast proliferation responsible for the development of fibrosis.

  15. Assessment of brown adipose tissue function

    PubMed Central

    Virtue, Sam; Vidal-Puig, Antonio

    2013-01-01

    In this review we discuss practical considerations for the assessment of brown adipose tissue in rodent models, focusing on mice. The central aim of the review is to provide a critical appraisal of the utility of specialized techniques for assessing brown adipose tissue function in vivo. We cover several of the most common specialized methods for analysing brown adipose tissue function in vivo, including assessment of maximal thermogenic capacity by indirect calorimetry and the measurement of sympathetic tone to brown adipose tissue. While these techniques are powerful, they are not readily available to all laboratories; therefore we also cover several simple measurements that, particularly in combination, can be used to determine if a mouse model is likely to have alterations in brown adipose tissue function. Such techniques include: pair feeding, analysis of brown adipose tissue lipid content and mRNA and protein markers of brown adipose tissue activation. PMID:23760815

  16. Microfluidic sampling system for tissue analytics

    PubMed Central

    Hokkanen, A.; Stuns, I.; Schmid, P.; Kokkonen, A.; Gao, F.; Steinecker, A.; Budczies, J.; Heimala, P.; Hakalahti, L.

    2015-01-01

    We have developed a microfluidics based sampling system for tissue analytics. The proof-of-concept of the sampling system was demonstrated by extracting lipid samples from tissue biopsies. The sample collection system consists of a disposable silicon based multiport microneedle integrated with polymer microfluidics. The polymethyl methacrylate polymer microfluidic chip has a 10 μl sample reservoir and actuation membranes for liquid pumping. A special automated robotic system was developed to control the positioning of the needle and the sampling procedure on preselected spots on the tissue. Real breast cancer tissue samples were used to test the feasibility of the sampling system. We successfully measured indicative cancer biomarkers from the tissue surface. Phosphatidylcholine and phosphoethanolamine were extracted from the tissue membrane with methyl tert-butyl ether solvent and detected by mass spectrometry. In the future, this tool could be used in characterization of preoperative biopsies and tumour tissues removed during surgery. PMID:26421088

  17. Multiscale tissue engineering for liver reconstruction

    PubMed Central

    Sudo, Ryo

    2014-01-01

    The liver is a target of in vitro tissue engineering despite its capability to regenerate in vivo. The construction of liver tissues in vitro remains challenging. In this review, conventional 3D cultures of hepatocytes are first discussed. Recent advances in the 3D culturing of liver cells are then summarized in the context of in vitro liver tissue reconstruction at the micro- and macroscales. The application of microfluidics technology to liver tissue engineering has been introduced as a bottom-up approach performed at the microscale, whereas whole-organ bioengineering technology was introduced as a top-down approach performed at the macroscale. Mesoscale approaches are also discussed in considering the integration of micro- and macroscale approaches. Multiple parallel multiscale liver tissue engineering studies are ongoing; however, no tissue-engineered liver that is appropriate for clinical use has yet been realized. The integration of multiscale tissue engineering studies is essential for further understanding of liver reconstruction strategies. PMID:24500493

  18. Bioengineered functional brain-like cortical tissue

    PubMed Central

    Tang-Schomer, Min D.; White, James D.; Tien, Lee W.; Schmitt, L. Ian; Valentin, Thomas M.; Graziano, Daniel J.; Hopkins, Amy M.; Omenetto, Fiorenzo G.; Haydon, Philip G.; Kaplan, David L.

    2014-01-01

    The brain remains one of the most important but least understood tissues in our body, in part because of its complexity as well as the limitations associated with in vivo studies. Although simpler tissues have yielded to the emerging tools for in vitro 3D tissue cultures, functional brain-like tissues have not. We report the construction of complex functional 3D brain-like cortical tissue, maintained for months in vitro, formed from primary cortical neurons in modular 3D compartmentalized architectures with electrophysiological function. We show that, on injury, this brain-like tissue responds in vitro with biochemical and electrophysiological outcomes that mimic observations in vivo. This modular 3D brain-like tissue is capable of real-time nondestructive assessments, offering previously unidentified directions for studies of brain homeostasis and injury. PMID:25114234

  19. Biomaterials for vascular tissue engineering

    PubMed Central

    Ravi, Swathi; Chaikof, Elliot L

    2010-01-01

    Cardiovascular disease is the leading cause of mortality in the USA. The limited availability of healthy autologous vessels for bypass grafting procedures has led to the fabrication of prosthetic vascular conduits. While synthetic polymers have been extensively studied as substitutes in vascular engineering, they fall short of meeting the biological challenges at the blood–material interface. Various tissue engineering strategies have emerged to address these flaws and increase long-term patency of vascular grafts. Vascular cell seeding of scaffolds and the design of bioactive polymers for in situ arterial regeneration have yielded promising results. This article describes the advances made in biomaterials design to generate suitable materials that not only match the mechanical properties of native vasculature, but also promote cell growth, facilitate extracellular matrix production and inhibit thrombogenicity. PMID:20017698

  20. Who "owns" cells and tissues?

    PubMed

    Lebacqz, K

    2001-01-01

    Opposition to 'ownership' of cells and tissues often depends on arguments about the special or sacred nature of human bodies and other living things. Such arguments are not very helpful in dealing with the patenting of DNA fragments. Two arguments undergird support for patenting: the notion that an author has a 'right' to an invention resulting from his/her labor, and the utilitarian argument that patents are needed to support medical inventiveness. The labor theory of ownership rights is subject to critique, thought it may still have enduring value. The more important argument is that deriving from the common good. If patents on DNA are supported on the basis of their contributions to the common good, then they can also be limited based on considerations of the common good.

  1. Heterophile Antibodies and Tissue Injury

    PubMed Central

    Tsai, Chi-Cheng; Taichman, Norton S.; Pulver, Wayne H.; Schönbaum, Eduard

    1973-01-01

    Platelets appear to be pathogenetic determinants in the development of lethal Forssman shock, which was provoked in guinea pigs by an intravenous injection of rabbit antiserum to sheep erythrocyte stromata. Within moments, circulating platelets (prelabeled with 14C-serotonin) were removed from the blood stream and impacted in the lungs, where they liberated 14C into the tissues. When animals were depleted of platelets prior to the production of shock, they survived for prolonged periods of time or were protected against death. Pretreatment with antiinflammatory compounds capable of inhibiting platelet aggregation and release phenomena had a similar protective influence. It would appear, therefore, that Forssman shock is a convenient and accessible model for investigating the mechanisms whereby platelets mediate immune vascular damage. ImagesFig 1Fig 2Fig 3Fig 4Fig 5 PMID:4740636

  2. Dynamic simulations of tissue welding

    SciTech Connect

    Maitland, D.J.; Eder, D.C.; London, R.A.; Glinsky, M.E.

    1996-02-01

    The exposure of human skin to near-infrared radiation is numerically simulated using coupled laser, thermal transport and mass transport numerical models. The computer model LATIS is applied in both one-dimensional and two-dimensional geometries. Zones within the skin model are comprised of a topical solder, epidermis, dermis, and fatty tissue. Each skin zone is assigned initial optical, thermal and water density properties consistent with values listed in the literature. The optical properties of each zone (i.e. scattering, absorption and anisotropy coefficients) are modeled as a kinetic function of the temperature. Finally, the water content in each zone is computed from water diffusion where water losses are accounted for by evaporative losses at the air-solder interface. The simulation results show that the inclusion of water transport and evaporative losses in the model are necessary to match experimental observations. Dynamic temperature and damage distributions are presented for the skin simulations.

  3. Bottom-up tissue engineering

    PubMed Central

    Elbert, Donald L.

    2011-01-01

    Recapitulating the elegant structures formed during development is an extreme synthetic and biological challenge. Great progress has been made in developing materials to support transplanted cells, yet the complexity of tissues is far beyond that found in even the most advanced scaffolds. Self-assembly is a motif used in development and a route for the production of complex materials. Self-assembly of peptides, proteins and other molecules at the nanoscale is promising, but in addition, intriguing ideas are emerging for self-assembly of micron-scale structures. In this brief review, very recent advances in the assembly of micron-scale cell aggregates and microgels will be described and discussed. PMID:21524904

  4. Confocal imaging of butterfly tissue.

    PubMed

    Brunetti, Craig R

    2014-01-01

    To understand the molecular events responsible for morphological change requires the ability to examine gene expression in a wide range of organisms in addition to model systems to determine how the differences in gene expression correlate with phenotypic differences. There are approximately 12,000 species of butterflies, most, with distinct patterns on their wings. The most important tool for studying gene expression in butterflies is confocal imaging of butterfly tissue by indirect immunofluorescence using either cross-reactive antibodies from closely related species such as Drosophila or developing butterfly-specific antibodies. In this report, we describe how indirect immunofluorescence protocols can be used to visualize protein expression patterns on the butterfly wing imaginal disc and butterfly embryo.

  5. Tissue grown in NASA Bioreactor

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Cells from kidneys lose some of their special features in conventional culture but form spheres replete with specialized cell microvilli (hair) and synthesize hormones that may be clinically useful. Ground-based research studies have demonstrated that both normal and neoplastic cells and tissues recreate many of the characteristics in the NASA bioreactor that they display in vivo. Proximal kidney tubule cells that normally have rich apically oriented microvilli with intercellular clefts in the kidney do not form any of these structures in conventional two-dimensional monolayer culture. However, when normal proximal renal tubule cells are cultured in three-dimensions in the bioreactor, both the microvilli and the intercellular clefts form. This is important because, when the morphology is recreated, the function is more likely also to be rejuvenated. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC).

  6. Freezing apparatus for biological tissue

    SciTech Connect

    Coulter, H.D.; Schober, W.E.

    1988-06-21

    An apparatus for treating specimens of tissue by bringing such specimens into contact with a surface is described, comprising: a base position to support the surface; a plunger slidably mounted with respect to the base for movement toward and away from the surface between first and second positions; means on the plunger on an end thereof facing the surface for supporting a specimen to be treated; mechanical linkage means for controlling movement of the plunger toward and away from the surface, the linkage means being operable to reduce the velocity of the plunger as it approaches the surface and the second position; and means for stopping the linkage means in a known position with the plunger in its second position and with a specimen supported by the plunger in contact with the surface.

  7. Tissue Microarrays in Clinical Oncology

    PubMed Central

    Voduc, David; Kenney, Challayne; Nielsen, Torsten O.

    2008-01-01

    The tissue microarray is a recently-implemented, high-throughput technology for the analysis of molecular markers in oncology. This research tool permits the rapid assessment of a biomarker in thousands of tumor samples, using commonly available laboratory assays such as immunohistochemistry and in-situ hybridization. Although introduced less than a decade ago, the TMA has proven to be invaluable in the study of tumor biology, the development of diagnostic tests, and the investigation of oncological biomarkers. This review describes the impact of TMA-based research in clinical oncology and its potential future applications. Technical aspects of TMA construction, and the advantages and disadvantages inherent to this technology are also discussed. PMID:18314063

  8. Tissue Engineered Strategies for Pseudoarthrosis

    PubMed Central

    Longo, Umile Giuseppe; Trovato, Ugo; Loppini, Mattia; Rizzello, Giacomo; Khan, Wasim Sardar; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Numerous classification systems of non-union have been proposed based on: presence or absence of infection, radiographic features, clinical findings, biologic activity, location and shape. The management of pseudarthrosis is strongly related to the type of non-union (infected versus uninfected, atrophic versus hypertrophic). Surgical management of pseudarthrosis is generally effective with a success rate ranging from 75 to 100%. Nevertheless, in a relatively high number of instances several combined treatments are required for the fracture healing. The current gold standard to stimulate the bone regeneration is represented by the revision surgery with the application of autologous bone grafts. However, several approaches have been described to promote and enhance the bone tissue regeneration, including extracorporeal shock wave therapy (ESWT), ultrasound, electromagnetic, bone morphogenic proteins (BMPs) and platelet-rich-plasma (PRP). The aim of the present study was to perform a systematic review of the literature evaluating the current therapies to promote and enhance the bone tissue healing. The systematic review was performed according to PRISMA guidelines with a PRISMA checklist and algorithm. Limitations of the present systematic review are mainly related to the scanty quality of the studies available in the literature. Although the therapies previously described for the management of patients with non-unions seems to be effective, the limitations of the included studies, especially the extensive clinical heterogeneity, make not possible to provide clear recommendations regarding the application of these approaches. The problems remain the need to better understand the most effective treatment options, subject to surgical stabilization as a first step. PMID:23248729

  9. Ultrasonic Histotripsy for Tissue Therapy

    NASA Astrophysics Data System (ADS)

    Pahk, K. J.; Dhar, D. K.; Malago, M.; Saffari, N.

    2015-01-01

    Hepatocyte transplantation has been considered and investigated as a promising and alternative method to liver transplantation for treating liver-based metabolic disorder in newborns over the past two decades. Although some clinical trials have been conducted and shown clinical benefits and outcomes, it is difficult to deliver and achieve a desired level of integration and transplantation of hepatocytes in the liver parenchyma. To overcome this problem, this work introduces an alternative method to a portal-infused-hepatocyte cell transplantation. To improve the level of engraftment of transplantable hepatocytes, these are injected directly into cavities generated by ultrasonic histotripsy. Histotripsy is an extracorporeal noninvasive technique which has been recently developed using high intensity focused ultrasound (HIFU) for inducing tissue fractionation with no coagulative necrosis. The exact mechanisms for the tissue fractionation are not well understood yet; but the possible mechanisms are thought to be a combination of nonlinear wave propagation effect, explosive bubble growth and ultrasonic atomization. The main objectives of this work are to demonstrate the feasibility of this new cell therapy and evaluate and distinguish between the different types of cavitation activity for either a thermally or a mechanically induced lesion. In the present work, numerical studies on the bubble dynamics (the Gilmore-Akulichev bubble model coupled with the Khokhlov-Zabolotskaya-Kuznetsov equation) and both ex- and in vivo liver experiments are conducted with histological analysis (haematoxylin and eosin stain). The numerical and the experimental results suggest that (a) the acoustic emissions emitted during the thermal ablation and the histotripsy exposure can be distinguished both numerically and experimentally and (b) the proposed cell therapy may potentially form an effective and safe clinical treatment for replacing and correcting disordered hepatocytes, although the

  10. [Connective tissue and prolapse genesis].

    PubMed

    Tremollieres, F

    2010-06-01

    The pathophysiology of pelvic floor disorders still remains not well understood. Increasing age as well as vaginal multiparity are the main commonly accepted factors. The hypothesis of a defect of connective tissues of the pelvic floor with aging due to collagen deficiency and/or elastic fiber degradation is often highlighted. The issue of a potential protective role of HRT is also discussed although the recent results from the WHI would suggest a negative impact of HRT on urinary incontinence, especially when HRT is initiated in elderly women, far from the menopause. Nevertheless, environmental factors cannot explain the full pathogenesis of pelvic organ prolapse (POP) and the contribution of genetic factors to the development of pelvic floor disorders is widely recognized. Support for a genetic influence on POP derives from reports suggesting that heritability is a strong contributing factor and a familial history of POP is considered as a classical risk factor. However, the characterization of the underlying molecular mechanisms remains limited, since POP may be considered the end result of a multifactorial process leading to destruction of vaginal wall connective tissue. Experimental studies in mice with null mutations in the genes encoding different putative factors involved in elastic fibers remodeling and homeostasis are crucial in the understanding of the pathogenesis of POP. Mice with null mutation in the gene encoding lysyl oxidase-like 1 (LOXL1) or fibulin-5, demonstrate signs of elastinopathy including the development of a POP in the postpartum. Likewise, homeobox genes such as HOXA11, which are essential in the embryonic development of the urogenital tract might also be involved in the pathogenesis of POP. The better understanding of the underlying determinants of pelvic floor disorders with a special focus on genetic factors may offer new therapeutic strategies, in addition to or replacement of surgical procedures.

  11. Tissue-resident macrophages: then and now.

    PubMed

    Davies, Luke C; Taylor, Philip R

    2015-04-01

    Macrophages have been at the heart of immune research for over a century and are an integral component of innate immunity. Macrophages are often viewed as terminally differentiated monocytic phagocytes. They infiltrate tissues during inflammation, and form polarized populations that perform pro-inflammatory or anti-inflammatory functions. Tissue-resident macrophages were regarded as differentiated monocytes, which seed the tissues to perform immune sentinel and homeostatic functions. However, tissue-resident macrophages are not a homogeneous population, but are in fact a grouping of cells with similar functions and phenotypes. In the last decade, it has been revealed that many of these cells are not terminally differentiated and, in most cases, are not derived from haematopoiesis in the adult. Recent research has highlighted that tissue-resident macrophages cannot be grouped into simple polarized categories, especially in vivo, when they are exposed to complex signalling events. It has now been demonstrated that the tissue environment itself is a major controller of macrophage phenotype, and can influence the expression of many genes regardless of origin. This is consistent with the concept that cells within different tissues have diverse responses in inflammation. There is still a mountain to climb in the field, as it evolves to encompass not only tissue-resident macrophage diversity, but also categorization of specific tissue environments and the plasticity of macrophages themselves. This knowledge provides a new perspective on therapeutic strategies, as macrophage subsets can potentially be manipulated to control the inflammatory environment in a tissue-specific manner. PMID:25684236

  12. Tissue expanders in reconstruction of maxillofacial defects.

    PubMed

    John, Jacob; Edward, Joseph; George, Joju

    2015-03-01

    Tissue expansion in its natural ways had fascinated man from prehistoric times itself. But tissue expansion for medical purposes was first tried and reported only in the early half of twentieth century. Presently the principle of tissue expansion is being used in reconstruction of many hard and soft tissue defects of larger dimension, which were previously regarded as great challenge for maxillofacial and plastic surgeons. Making use of the viscoelastic nature of the skin, considerable amount of tissue expansion based tissue engineering is possible in the maxillofacial region. Here we present a case of a facial scar of large dimension with a central oro cutaneous fistula developed as a result of facial artery blow out in a 24 year old female for which esthetic correction was done using the excess tissue obtained from tissue expansion. In this case where other methods of reconstruction such as local flaps, free flaps and normal tissue grafts were assessed to be non viable, tissue expansion was found to be an apt solution for esthetic reconstruction. PMID:25848145

  13. Tissue Specificity of Human Disease Module

    PubMed Central

    Kitsak, Maksim; Sharma, Amitabh; Menche, Jörg; Guney, Emre; Ghiassian, Susan Dina; Loscalzo, Joseph; Barabási, Albert-László

    2016-01-01

    Genes carrying mutations associated with genetic diseases are present in all human cells; yet, clinical manifestations of genetic diseases are usually highly tissue-specific. Although some disease genes are expressed only in selected tissues, the expression patterns of disease genes alone cannot explain the observed tissue specificity of human diseases. Here we hypothesize that for a disease to manifest itself in a particular tissue, a whole functional subnetwork of genes (disease module) needs to be expressed in that tissue. Driven by this hypothesis, we conducted a systematic study of the expression patterns of disease genes within the human interactome. We find that genes expressed in a specific tissue tend to be localized in the same neighborhood of the interactome. By contrast, genes expressed in different tissues are segregated in distinct network neighborhoods. Most important, we show that it is the integrity and the completeness of the expression of the disease module that determines disease manifestation in selected tissues. This approach allows us to construct a disease-tissue network that confirms known and predicts unexpected disease-tissue associations. PMID:27748412

  14. Tissue morphogenesis: a surface buckling mechanism.

    PubMed

    Volokh, Konstantin Y

    2006-01-01

    Surface patterns can emerge during growth of anisotropic tissues because of surface buckling. This morphogenetic scenario is examined in the present paper based on a simple phenomenological theory of tissue growth. In particular, we show that constrained growth can lead to tissue compression, which in turn may result in surface buckling of the tissue. The latter means the appearance of wavy patterns on the surface. These patterns decay away from the surface. It is interesting that the critical magnitude of the parameter of mass supply, which corresponds to surface buckling, is independent of the pattern wavelength and various patterns can generally be generated in growth. Results of theoretical analysis show that the surface buckling scenario is realistic if the growing tissue matches the following two conditions. First, compression should appear during tissue growth. Second, the tissue should exhibit strong anisotropy. The former condition does not necessarily mean geometric constraints: inhomogeneous growth or material inhomogeneity and anisotropy can lead to the appearance of compressive stresses. The latter condition is typical of some tissues with fiber reinforcement in planes parallel to the surface. In the latter case, the tissue material is much softer in the out-of-plane direction than in plane. The creation of patterns by restraining tissue growth and forcing the surface to buckle represents a challenging experimental problem.

  15. Detecting and profiling tissue-selective genes.

    PubMed

    Liang, Shuang; Li, Yizheng; Be, Xiaobing; Howes, Steve; Liu, Wei

    2006-07-12

    The widespread use of DNA microarray technologies has generated large amounts of data from various tissue and/or cell types. These data set the stage to answer the question of tissue specificity of human transcriptome in a comprehensive manner. Our focus is to uncover the tissue-gene relationship by identifying genes that are preferentially expressed in a small number of tissue types. The tissue selectivity would shed light on the potential physiological functions of these genes and provides an indispensable reference to compare against disease pathophysiology and to identify or validate tissue-specific drug targets. Here we describe a systematic computational and statistical approach to profile gene expression data to identify tissue-selective genes with the use of a more extensive data set and a well-established multiple-comparison procedure with error rate control. Expression data of 35,152 probe sets in 97 normal human tissue types were analyzed, and 3,919 genes were identified to be selective to one or a few tissue types. We presented results of these tissue-selective genes and compared them to those identified by other studies.

  16. Laser capture microdissection in the tissue biorepository.

    PubMed

    Liu, Angen

    2010-09-01

    An important need of many cancer research projects is the availability of high-quality, appropriately selected tissue. Tissue biorepositories are organized to collect, process, store, and distribute samples of tumor and normal tissue for further use in fundamental and translational cancer research. This, in turn, provides investigators with an invaluable resource of appropriately examined and characterized tissue specimens and linked patient information. Human tissues, in particular, tumor tissues, are complex structures composed of heterogeneous mixtures of morphologically and functionally distinct cell types. It is essential to analyze specific cell types to identify and define accurately the biologically important processes in pathologic lesions. Laser capture microdissection (LCM) is state-of-the-art technology that provides the scientific community with a rapid and reliable method to isolate a homogeneous population of cells from heterogeneous tissue specimens, thus providing investigators with the ability to analyze DNA, RNA, and protein accurately from pure populations of cells. This is particularly well-suited for tumor cell isolation, which can be captured from complex tissue samples. The combination of LCM and a tissue biorepository offers a comprehensive means by which researchers can use valuable human biospecimens and cutting-edge technology to facilitate basic, translational, and clinical research. This review provides an overview of LCM technology with an emphasis on the applications of LCM in the setting of a tissue biorepository, based on the author's extensive experience in LCM procedures acquired at Fox Chase Cancer Center and Hollings Cancer Center.

  17. Multiscale mechanical modeling of soft biological tissues

    NASA Astrophysics Data System (ADS)

    Stylianopoulos, Triantafyllos

    2008-10-01

    Soft biological tissues include both native and artificial tissues. In the human body, tissues like the articular cartilage, arterial wall, and heart valve leaflets are examples of structures composed of an underlying network of collagen fibers, cells, proteins and molecules. Artificial tissues are less complex than native tissues and mainly consist of a fiber polymer network with the intent of replacing lost or damaged tissue. Understanding of the mechanical function of these materials is essential for many clinical treatments (e.g. arterial clamping, angioplasty), diseases (e.g. arteriosclerosis) and tissue engineering applications (e.g. engineered blood vessels or heart valves). This thesis presents the derivation and application of a multiscale methodology to describe the macroscopic mechanical function of soft biological tissues incorporating directly their structural architecture. The model, which is based on volume averaging theory, accounts for structural parameters such as the network volume fraction and orientation, the realignment of the fibers in response to strain, the interactions among the fibers and the interactions between the fibers and the interstitial fluid in order to predict the overall tissue behavior. Therefore, instead of using a constitutive equation to relate strain to stress, the tissue microstructure is modeled within a representative volume element (RVE) and the macroscopic response at any point in the tissue is determined by solving a micromechanics problem in the RVE. The model was applied successfully to acellular collagen gels, native blood vessels, and electrospun polyurethane scaffolds and provided accurate predictions for permeability calculations in isotropic and oriented fiber networks. The agreement of model predictions with experimentally determined mechanical properties provided insights into the mechanics of tissues and tissue constructs, while discrepancies revealed limitations of the model framework.

  18. Photon dynamics in tissue imaging

    NASA Astrophysics Data System (ADS)

    Chance, Britton; Haselgrove, John C.; Wang, NaiGuang; Maris, Michael B.; Sevick-Muraca, Eva M.

    1991-11-01

    The emerging need for a fast, safe economical approach to global and localized measures of desaturation of hemoglobin with oxygen (HbO2) in the human brain motivates further research on time-resolved spectroscopy in four areas of study. (1) To afford quantization of hemoglobin saturation through time-resolved spectroscopy in the time domain (TD) and in the frequency domain (FD). Evaluation of dual-wavelength TD and FD spectrometers for determining quantitatively hemoglobin desaturation and blood-volume changes by calculations that are insensitive to mutual interference is proposed. The diffusion equation, as it applies especially to TD studies, and the absorption ((mu) a) and scattering ((mu) s) coefficients provide their independent determination from the late and early respective portions of the kinetics of the emergent photons in response to a short input pulse (50-100 psec). (2) The identification of the photon-pathlength change due to the arterial pulse in the brain tissue by FD methods with Fourier transformation affords an opportunity to employ principles of pulse oximetry to vessels localized deep within the brain tissue. (3) Localization of desaturation of hemoglobin in portions of the brain can be achieved through dual-wavelength scanning of the input/output optical fibers across the head for an X-Y coordinate and varying the distance between input and output ((rho) ) or the time delay in data acquisition to afford an in-depth Z scan. Localizations of shed blood, which have an effective concentration of over 10 times that of capillary-bed blood, are identified by X, Y, Z scans using only a single wavelength. (4) Independent measurements of absorption ((mu) a) and scattering ((mu) s) coefficients, particularly by TD techniques, affords structural mapping of the brain, which can be used to diagnose brain tumor and neuronal degeneration. Two experimental systems are used to critically evaluate these studies; the first, a hemoglobin/lipid/yeast model in which

  19. Radiation Effect on Human Tissue

    NASA Technical Reports Server (NTRS)

    Richmond, Robert C.; Cruz, Angela; Bors, Karen; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Predicting the occurrence of human cancer following exposure of an epidemiologic population to any agent causing genetic damage is a difficult task. To an approximation, this is because the uncertainty of uniform exposure to the damaging agent, and the uncertainty of uniform processing of that damage within a complex set of biological variables, degrade the confidence of predicting the delayed expression of cancer as a relatively rare event within clinically normal individuals. This situation begs the need for alternate controlled experimental models that are predictive for the development of human cancer following exposures to agents causing genetic damage. Such models historically have not been of substantial proven value. It is more recently encouraging, however, that developments in molecular and cell biology have led to an expanded knowledge of human carcinogenesis, and of molecular markers associated with that process. It is therefore appropriate to consider new laboratory models developed to accomodate that expanded knowledge in order to assess the cancer risks associated with exposures to genotoxic agents. When ionizing radiation of space is the genotoxic agent, then a series of additional considerations for human cancer risk assessment must also be applied. These include the dose of radiation absorbed by tissue at different locations in the body, the quality of the absorbed radiation, the rate at which absorbed dose accumulates in tissue, the way in which absorbed dose is measured and calculated, and the alterations in incident radiation caused by shielding materials. It is clear that human cancer risk assessment for damage caused by ionizing radiation is a multidisciplinary responsibility, and that within this responsibility no single discipline can hold disproportionate sway if a risk assessment model of radiation-induced human cancer is to be developed that has proven value. Biomolecular and cellular markers from the work reported here are considered

  20. Engineering Complex Orthopaedic Tissues via Strategic Biomimicry

    PubMed Central

    Qu, Dovina; Mosher, Christopher Z.; Boushell, Margaret K.; Lu, Helen H.

    2014-01-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, whereby overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g. bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g. bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g. bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  1. Engineering complex orthopaedic tissues via strategic biomimicry.

    PubMed

    Qu, Dovina; Mosher, Christopher Z; Boushell, Margaret K; Lu, Helen H

    2015-03-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, wherein overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g., bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g., bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g., bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  2. Principles, Techniques, and Applications of Tissue Microfluidics

    NASA Technical Reports Server (NTRS)

    Wade, Lawrence A.; Kartalov, Emil P.; Shibata, Darryl; Taylor, Clive

    2011-01-01

    The principle of tissue microfluidics and its resultant techniques has been applied to cell analysis. Building microfluidics to suit a particular tissue sample would allow the rapid, reliable, inexpensive, highly parallelized, selective extraction of chosen regions of tissue for purposes of further biochemical analysis. Furthermore, the applicability of the techniques ranges beyond the described pathology application. For example, they would also allow the posing and successful answering of new sets of questions in many areas of fundamental research. The proposed integration of microfluidic techniques and tissue slice samples is called tissue microfluidics because it molds the microfluidic architectures in accordance with each particular structure of each specific tissue sample. Thus, microfluidics can be built around the tissues, following the tissue structure, or alternatively, the microfluidics can be adapted to the specific geometry of particular tissues. By contrast, the traditional approach is that microfluidic devices are structured in accordance with engineering considerations, while the biological components in applied devices are forced to comply with these engineering presets. The proposed principles represent a paradigm shift in microfluidic technology in three important ways: Microfluidic devices are to be directly integrated with, onto, or around tissue samples, in contrast to the conventional method of off-chip sample extraction followed by sample insertion in microfluidic devices. Architectural and operational principles of microfluidic devices are to be subordinated to suit specific tissue structure and needs, in contrast to the conventional method of building devices according to fluidic function alone and without regard to tissue structure. Sample acquisition from tissue is to be performed on-chip and is to be integrated with the diagnostic measurement within the same device, in contrast to the conventional method of off-chip sample prep and

  3. Engineering complex orthopaedic tissues via strategic biomimicry.

    PubMed

    Qu, Dovina; Mosher, Christopher Z; Boushell, Margaret K; Lu, Helen H

    2015-03-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, wherein overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g., bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g., bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g., bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  4. Nanotechnology in the Regeneration of Complex Tissues

    PubMed Central

    Cassidy, John W.

    2015-01-01

    Modern medicine faces a growing crisis as demand for organ transplantations continues to far outstrip supply. By stimulating the body’s own repair mechanisms, regenerative medicine aims to reduce demand for organs, while the closely related field of tissue engineering promises to deliver “off-the-self” organs grown from patients’ own stem cells to improve supply. To deliver on these promises, we must have reliable means of generating complex tissues. Thus far, the majority of successful tissue engineering approaches have relied on macroporous scaffolds to provide cells with both mechanical support and differentiative cues. In order to engineer complex tissues, greater attention must be paid to nanoscale cues present in a cell’s microenvironment. As the extracellular matrix is capable of driving complexity during development, it must be understood and reproduced in order to recapitulate complexity in engineered tissues. This review will summarize current progress in engineering complex tissue through the integration of nanocomposites and biomimetic scaffolds. PMID:26097381

  5. Heart Regeneration with Engineered Myocardial Tissue

    PubMed Central

    Bajpai, Vivek K.; Andreadis, Stelios T.; Murry, Charles E.

    2014-01-01

    Heart disease is the leading cause of morbidity and mortality worldwide, and regenerative therapies that replace damaged myocardium could benefit millions of patients annually. The many cell types in the heart, including cardiomyocytes, endothelial cells, vascular smooth muscle cells, pericytes, and cardiac fibroblasts, communicate via intercellular signaling and modulate each other’s function. Although much progress has been made in generating cells of the cardiovascular lineage from human pluripotent stem cells, a major challenge now is creating the tissue architecture to integrate a microvascular circulation and afferent arterioles into such an engineered tissue. Recent advances in cardiac and vascular tissue engineering will move us closer to the goal of generating functionally mature tissue. Using the biology of the myocardium as the foundation for designing engineered tissue and addressing the challenges to implantation and integration, we can bridge the gap from bench to bedside for a clinically tractable engineered cardiac tissue. PMID:24819474

  6. Macrophages in Tissue Repair, Regeneration, and Fibrosis.

    PubMed

    Wynn, Thomas A; Vannella, Kevin M

    2016-03-15

    Inflammatory monocytes and tissue-resident macrophages are key regulators of tissue repair, regeneration, and fibrosis. After tissue injury, monocytes and macrophages undergo marked phenotypic and functional changes to play critical roles during the initiation, maintenance, and resolution phases of tissue repair. Disturbances in macrophage function can lead to aberrant repair, such that uncontrolled production of inflammatory mediators and growth factors, deficient generation of anti-inflammatory macrophages, or failed communication between macrophages and epithelial cells, endothelial cells, fibroblasts, and stem or tissue progenitor cells all contribute to a state of persistent injury, and this could lead to the development of pathological fibrosis. In this review, we discuss the mechanisms that instruct macrophages to adopt pro-inflammatory, pro-wound-healing, pro-fibrotic, anti-inflammatory, anti-fibrotic, pro-resolving, and tissue-regenerating phenotypes after injury, and we highlight how some of these mechanisms and macrophage activation states could be exploited therapeutically.

  7. Adipose and mammary epithelial tissue engineering.

    PubMed

    Zhu, Wenting; Nelson, Celeste M

    2013-01-01

    Breast reconstruction is a type of surgery for women who have had a mastectomy, and involves using autologous tissue or prosthetic material to construct a natural-looking breast. Adipose tissue is the major contributor to the volume of the breast, whereas epithelial cells comprise the functional unit of the mammary gland. Adipose-derived stem cells (ASCs) can differentiate into both adipocytes and epithelial cells and can be acquired from autologous sources. ASCs are therefore an attractive candidate for clinical applications to repair or regenerate the breast. Here we review the current state of adipose tissue engineering methods, including the biomaterials used for adipose tissue engineering and the application of these techniques for mammary epithelial tissue engineering. Adipose tissue engineering combined with microfabrication approaches to engineer the epithelium represents a promising avenue to replicate the native structure of the breast.

  8. Tissue Engineering: Step Ahead in Maxillofacial Reconstruction

    PubMed Central

    Rai, Raj; Raval, Rushik; Khandeparker, Rakshit Vijay Sinai; Chidrawar, Swati K; Khan, Abdul Ahad; Ganpat, Makne Sachin

    2015-01-01

    Within the precedent decade, a new field of “tissue engineering” or “tissue regeneration” emerge that offers an innovative and exhilarating substitute for maxillofacial reconstruction. It offers a new option to supplement existing treatment regimens for reconstruction/regeneration of the oral and craniofacial complex, which includes the teeth, periodontium, bones, soft tissues (oral mucosa, conjunctiva, skin), salivary glands, and the temporomandibular joint (bone and cartilage), as well as blood vessels, muscles, tendons, and nerves. Tissue engineering is based on harvesting the stem cells which are having potential to form an organ. Harvested cells are then transferred into scaffolds that are manufactured in a laboratory to resemble the structure of the desired tissue to be replaced. This article reviews the principles of tissue engineering and its various applications in oral and maxillofacial surgery. PMID:26435634

  9. Mitochondria and endocrine function of adipose tissue.

    PubMed

    Medina-Gómez, Gema

    2012-12-01

    Excess of adipose tissue is accompanied by an increase in the risk of developing insulin resistance, type 2 diabetes (T2D) and other complications. Nevertheless, total or partial absence of fat or its accumulation in other tissues (lipotoxicity) is also associated to these complications. White adipose tissue (WAT) was traditionally considered a metabolically active storage tissue for lipids while brown adipose tissue (BAT) was considered as a thermogenic adipose tissue with higher oxidative capacity. Nowadays, WAT is also considered an endocrine organ that contributes to energy homeostasis. Experimental evidence tends to link the malfunction of adipose mitochondria with the development of obesity and T2D. This review discusses the importance of mitochondrial function in adipocyte biology and the increased evidences of mitochondria dysfunction in these epidemics. New strategies targeting adipocyte mitochondria from WAT and BAT are also discussed as therapies against obesity and its complications in the near future. PMID:23168280

  10. Bubble dynamics in perfused tissue undergoing decompression.

    PubMed

    Meisel, S; Nir, A; Kerem, D

    1981-02-01

    A mathematical model describing bubble dynamics in a perfused tissue undergoing decompression is presented, taking into account physical expansion and inward diffusion from surrounding supersaturated tissue as growth promoting factors and tissue gas elimination by perfusion, tissue elasticity, surface tension and inherent unsaturation as resolving driving forces. The expected behavior after a step reduction of pressure of a bubble initially existing in the tissue, displaying both growth and resolution has been demonstrated. A strong perfusion-dependence of bubble resolution time at low perfusion rates is apparent. The model can account for various exposure pressures and saturation fractions of any inert gas-tissue combination for which a set of physical and physiological parameters is available.

  11. Tissue Engineering: Step Ahead in Maxillofacial Reconstruction.

    PubMed

    Rai, Raj; Raval, Rushik; Khandeparker, Rakshit Vijay Sinai; Chidrawar, Swati K; Khan, Abdul Ahad; Ganpat, Makne Sachin

    2015-09-01

    Within the precedent decade, a new field of "tissue engineering" or "tissue regeneration" emerge that offers an innovative and exhilarating substitute for maxillofacial reconstruction. It offers a new option to supplement existing treatment regimens for reconstruction/regeneration of the oral and craniofacial complex, which includes the teeth, periodontium, bones, soft tissues (oral mucosa, conjunctiva, skin), salivary glands, and the temporomandibular joint (bone and cartilage), as well as blood vessels, muscles, tendons, and nerves. Tissue engineering is based on harvesting the stem cells which are having potential to form an organ. Harvested cells are then transferred into scaffolds that are manufactured in a laboratory to resemble the structure of the desired tissue to be replaced. This article reviews the principles of tissue engineering and its various applications in oral and maxillofacial surgery.

  12. Biomaterials for hollow organ tissue engineering.

    PubMed

    Hendow, Eseelle K; Guhmann, Pauline; Wright, Bernice; Sofokleous, Panagiotis; Parmar, Nina; Day, Richard M

    2016-01-01

    Tissue engineering is a rapidly advancing field that is likely to transform how medicine is practised in the near future. For hollow organs such as those found in the cardiovascular and respiratory systems or gastrointestinal tract, tissue engineering can provide replacement of the entire organ or provide restoration of function to specific regions. Larger tissue-engineered constructs often require biomaterial-based scaffold structures to provide support and structure for new tissue growth. Consideration must be given to the choice of material and manufacturing process to ensure the de novo tissue closely matches the mechanical and physiological properties of the native tissue. This review will discuss some of the approaches taken to date for fabricating hollow organ scaffolds and the selection of appropriate biomaterials. PMID:27014369

  13. Definitions and Overview of Tissue Optics

    NASA Astrophysics Data System (ADS)

    Welch, Ashley J.; van Gemert, Martin J. C.; Star, Willem M.

    Optics for laser irradiation of tissue is best described by examining the response of a target within tissue to light. Suppose tissue (e.g. skin) has a chromophore, (e.g. a melanocyte) somewhere inside the tissue at coordinate {r}(x,y,z) with respect to some frame of reference (Fig. 3.1). What is the rate of heat that is generated in the chromophore when the tissue is irradiated at some wavelength with constant power P over the laser beam radius w L ? The key question that needs to be answered is: how many photons per second will reach the chromophore and be absorbed. Tissue optics should provide the answer to this question.

  14. Adipose and mammary epithelial tissue engineering

    PubMed Central

    Zhu, Wenting; Nelson, Celeste M.

    2013-01-01

    Breast reconstruction is a type of surgery for women who have had a mastectomy, and involves using autologous tissue or prosthetic material to construct a natural-looking breast. Adipose tissue is the major contributor to the volume of the breast, whereas epithelial cells comprise the functional unit of the mammary gland. Adipose-derived stem cells (ASCs) can differentiate into both adipocytes and epithelial cells and can be acquired from autologous sources. ASCs are therefore an attractive candidate for clinical applications to repair or regenerate the breast. Here we review the current state of adipose tissue engineering methods, including the biomaterials used for adipose tissue engineering and the application of these techniques for mammary epithelial tissue engineering. Adipose tissue engineering combined with microfabrication approaches to engineer the epithelium represents a promising avenue to replicate the native structure of the breast. PMID:23628872

  15. Intermuscular and intramuscular adipose tissues: Bad vs. good adipose tissues

    PubMed Central

    Hausman, Gary J; Basu, Urmila; Du, Min; Fernyhough-Culver, Melinda; Dodson, Michael V

    2014-01-01

    Human studies of the influence of aging and other factors on intermuscular fat (INTMF) were reviewed. Intermuscular fat increased with weight loss, weight gain, or with no weight change with age in humans. An increase in INTMF represents a similar threat to type 2 diabetes and insulin resistance as does visceral adipose tissue (VAT). Studies of INTMF in animals covered topics such as quantitative deposition and genetic relationships with other fat depots. The relationship between leanness and higher proportions of INTMF fat in pigs was not observed in human studies and was not corroborated by other pig studies. In humans, changes in muscle mass, strength and quality are associated with INTMF accretion with aging. Gene expression profiling and intrinsic methylation differences in pigs demonstrated that INTMF and VAT are primarily associated with inflammatory and immune processes. It seems that in the pig and humans, INTMF and VAT share a similar pattern of distribution and a similar association of components dictating insulin sensitivity. Studies on intramuscular (IM) adipocyte development in meat animals were reviewed. Gene expression analysis and genetic analysis have identified candidate genes involved in IM adipocyte development. Intramuscular (IM) adipocyte development in human muscle is only seen during aging and some pathological circumstance. Several genetic links between human and meat animal adipogenesis have been identified. In pigs, the Lipin1 and Lipin 2 gene have strong genetic effects on IM accumulation. Lipin1 deficiency results in immature adipocyte development in human lipodystrophy. In humans, overexpression of Perilipin 2 (PLIN2) facilitates intramyocellular lipid accretion whereas in pigs PLIN2 gene expression is associated with IM deposition. Lipins and perilipins may influence intramuscular lipid regardless of species. PMID:26317048

  16. Intermuscular and intramuscular adipose tissues: Bad vs. good adipose tissues.

    PubMed

    Hausman, Gary J; Basu, Urmila; Du, Min; Fernyhough-Culver, Melinda; Dodson, Michael V

    2014-01-01

    Human studies of the influence of aging and other factors on intermuscular fat (INTMF) were reviewed. Intermuscular fat increased with weight loss, weight gain, or with no weight change with age in humans. An increase in INTMF represents a similar threat to type 2 diabetes and insulin resistance as does visceral adipose tissue (VAT). Studies of INTMF in animals covered topics such as quantitative deposition and genetic relationships with other fat depots. The relationship between leanness and higher proportions of INTMF fat in pigs was not observed in human studies and was not corroborated by other pig studies. In humans, changes in muscle mass, strength and quality are associated with INTMF accretion with aging. Gene expression profiling and intrinsic methylation differences in pigs demonstrated that INTMF and VAT are primarily associated with inflammatory and immune processes. It seems that in the pig and humans, INTMF and VAT share a similar pattern of distribution and a similar association of components dictating insulin sensitivity. Studies on intramuscular (IM) adipocyte development in meat animals were reviewed. Gene expression analysis and genetic analysis have identified candidate genes involved in IM adipocyte development. Intramuscular (IM) adipocyte development in human muscle is only seen during aging and some pathological circumstance. Several genetic links between human and meat animal adipogenesis have been identified. In pigs, the Lipin1 and Lipin 2 gene have strong genetic effects on IM accumulation. Lipin1 deficiency results in immature adipocyte development in human lipodystrophy. In humans, overexpression of Perilipin 2 (PLIN2) facilitates intramyocellular lipid accretion whereas in pigs PLIN2 gene expression is associated with IM deposition. Lipins and perilipins may influence intramuscular lipid regardless of species.

  17. Cell sheet-based tissue engineering for fabricating 3-dimensional heart tissues.

    PubMed

    Shimizu, Tatsuya

    2014-01-01

    In addition to stem cell biology, tissue engineering is an essential research field for regenerative medicine. In contrast to cell injection, bioengineered tissue transplantation minimizes cell loss and has the potential to repair tissue defects. A popular approach is scaffold-based tissue engineering, which utilizes a biodegradable polymer scaffold for seeding cells; however, new techniques of cell sheet-based tissue engineering have been developed. Cell sheets are harvested from temperature-responsive culture dishes by simply lowering the temperature. Monolayer or stacked cell sheets are transplantable directly onto damaged tissues and cell sheet transplantation has already been clinically applied. Cardiac cell sheet stacking produces pulsatile heart tissue; however, lack of vasculature limits the viable tissue thickness to 3 layers. Multistep transplantation of triple-layer cardiac cell sheets cocultured with endothelial cells has been used to form thick vascularized cardiac tissue in vivo. Furthermore, in vitro functional blood vessel formation within 3-dimensional (3D) tissues has been realized by successfully imitating in vivo conditions. Triple-layer cardiac cell sheets containing endothelial cells were layered on vascular beds and the constructs were media-perfused using novel bioreactor systems. Interestingly, cocultured endothelial cells migrate into the vascular beds and form perfusable blood vessels. An in vitro multistep procedure has also enabled the fabrication of thick, vascularized heart tissues. Cell sheet-based tissue engineering has revealed great potential to fabricate 3D cardiac tissues and should contribute to future treatment of severe heart diseases and human tissue model production.

  18. Skin and Soft Tissue Infections.

    PubMed

    Ramakrishnan, Kalyanakrishnan; Salinas, Robert C; Agudelo Higuita, Nelson Ivan

    2015-09-15

    Skin and soft tissue infections result from microbial invasion of the skin and its supporting structures. Management is determined by the severity and location of the infection and by patient comorbidities. Infections can be classified as simple (uncomplicated) or complicated (necrotizing or nonnecrotizing), or as suppurative or nonsuppurative. Most community-acquired infections are caused by methicillin-resistant Staphylococcus aureus and beta-hemolytic streptococcus. Simple infections are usually monomicrobial and present with localized clinical findings. In contrast, complicated infections can be mono- or polymicrobial and may present with systemic inflammatory response syndrome. The diagnosis is based on clinical evaluation. Laboratory testing may be required to confirm an uncertain diagnosis, evaluate for deep infections or sepsis, determine the need for inpatient care, and evaluate and treat comorbidities. Initial antimicrobial choice is empiric, and in simple infections should cover Staphylococcus and Streptococcus species. Patients with complicated infections, including suspected necrotizing fasciitis and gangrene, require empiric polymicrobial antibiotic coverage, inpatient treatment, and surgical consultation for debridement. Superficial and small abscesses respond well to drainage and seldom require antibiotics. Immunocompromised patients require early treatment and antimicrobial coverage for possible atypical organisms. PMID:26371732

  19. Tissue Regeneration: A Silk Road.

    PubMed

    Jao, Dave; Mou, Xiaoyang; Hu, Xiao

    2016-01-01

    Silk proteins are natural biopolymers that have extensive structural possibilities for chemical and mechanical modifications to facilitate novel properties, functions, and applications in the biomedical field. The versatile processability of silk fibroins (SF) into different forms such as gels, films, foams, membranes, scaffolds, and nanofibers makes it appealing in a variety of applications that require mechanically superior, biocompatible, biodegradable, and functionalizable biomaterials. There is no doubt that nature is the world's best biological engineer, with simple, exquisite but powerful designs that have inspired novel technologies. By understanding the surface interaction of silk materials with living cells, unique characteristics can be implemented through structural modifications, such as controllable wettability, high-strength adhesiveness, and reflectivity properties, suggesting its potential suitability for surgical, optical, and other biomedical applications. All of the interesting features of SF, such as tunable biodegradation, anti-bacterial properties, and mechanical properties combined with potential self-healing modifications, make it ideal for future tissue engineering applications. In this review, we first demonstrate the current understanding of the structures and mechanical properties of SF and the various functionalizations of SF matrices through chemical and physical manipulations. Then the diverse applications of SF architectures and scaffolds for different regenerative medicine will be discussed in detail, including their current applications in bone, eye, nerve, skin, tendon, ligament, and cartilage regeneration.

  20. Tissue Regeneration: A Silk Road.

    PubMed

    Jao, Dave; Mou, Xiaoyang; Hu, Xiao

    2016-01-01

    Silk proteins are natural biopolymers that have extensive structural possibilities for chemical and mechanical modifications to facilitate novel properties, functions, and applications in the biomedical field. The versatile processability of silk fibroins (SF) into different forms such as gels, films, foams, membranes, scaffolds, and nanofibers makes it appealing in a variety of applications that require mechanically superior, biocompatible, biodegradable, and functionalizable biomaterials. There is no doubt that nature is the world's best biological engineer, with simple, exquisite but powerful designs that have inspired novel technologies. By understanding the surface interaction of silk materials with living cells, unique characteristics can be implemented through structural modifications, such as controllable wettability, high-strength adhesiveness, and reflectivity properties, suggesting its potential suitability for surgical, optical, and other biomedical applications. All of the interesting features of SF, such as tunable biodegradation, anti-bacterial properties, and mechanical properties combined with potential self-healing modifications, make it ideal for future tissue engineering applications. In this review, we first demonstrate the current understanding of the structures and mechanical properties of SF and the various functionalizations of SF matrices through chemical and physical manipulations. Then the diverse applications of SF architectures and scaffolds for different regenerative medicine will be discussed in detail, including their current applications in bone, eye, nerve, skin, tendon, ligament, and cartilage regeneration. PMID:27527229

  1. Tissue factor activity under flow.

    PubMed

    Diamond, Scott L

    2010-04-01

    Coagulation processes under flow conditions are fundamentally different when compared to whole blood clotting in a tube. Due to red blood cell migration toward the center of the vessel, platelet concentrations are elevated several-fold in the plasma layer near the wall or thrombus. Evaluation of platelet function, coagulation proteases, and pharmacological agents can utilize closed systems of constant volume that lack flow (eg. intracellular calcium measurement, automated calibrated thrombography) or include flow (eg. aggregometry or cone-and-plate viscometry). However, these laboratory approaches fail to recreate the fact that intravascular thrombosis is an open system where blood is continually flowing over a thrombotic site. In open systems, the rapid accumulation of platelets at a surface leads to platelet concentrations greatly exceeding those found in whole blood and the delivery/removal of species by convection may impact the efficacy of pharmacological agents. During a clotting event under flow, platelets can accumulate via adhesion receptors to concentrations that are 10 to 50-fold higher than that of platelet-rich plasma. Using controlled in vitro perfusions of whole blood, it is possible to determine the critical level of surface tissue factor needed to trigger full scale coagulation on collagen. Such in vitro perfusion systems also allow a determination of the potency of anti-platelet agents as a function of wall shear rate.

  2. [Sex steroids and bone tissue].

    PubMed

    Ribot, C; Tremollieres, F

    1995-01-01

    The precise mechanism of action of sexual steroids in the regulation of bone tissue is still poorly understood. Besides the indirect action via the production of calciotropic hormones, the fact that receptors respond to oestrogens as well as to androgens and progesterone is evidence that sexual steroids have a direct action in regulating bone activity. The anti-osteoclastic action of oestrogens, via the modulation in osteoblastic production of different substances such as interleukin-1 and -6, TGF beta, GM-CSF which inhibit osteoclastogenesis and bone resorption activity, is well documented. More recently, the direct role in osteoclast inhibition was suggested by the observation that osteoclasts carry oestrogen receptors. Likewise, certain in vivo and in vitro data suggest that oestrogens could also have a positive effect on bone formation regulation. For androgens, currently available data show that in vitro stimulation of bone formation, with increased proliferation and cell differentiation, could be mediated by TGF beta. The role of progesterone is more recently known. In vivo, progesterone increases cell growth and IFGF-II secretion by non-transformed human osteoblasts. The number of potential mechanisms which have already been demonstrated suggest the complexity of sex hormone regulation which leads to the final situation of physiological calcium sparing in the skeleton while maintaining skeletal structure. PMID:7747921

  3. Tissue Regeneration: A Silk Road

    PubMed Central

    Jao, Dave; Mou, Xiaoyang; Hu, Xiao

    2016-01-01

    Silk proteins are natural biopolymers that have extensive structural possibilities for chemical and mechanical modifications to facilitate novel properties, functions, and applications in the biomedical field. The versatile processability of silk fibroins (SF) into different forms such as gels, films, foams, membranes, scaffolds, and nanofibers makes it appealing in a variety of applications that require mechanically superior, biocompatible, biodegradable, and functionalizable biomaterials. There is no doubt that nature is the world’s best biological engineer, with simple, exquisite but powerful designs that have inspired novel technologies. By understanding the surface interaction of silk materials with living cells, unique characteristics can be implemented through structural modifications, such as controllable wettability, high-strength adhesiveness, and reflectivity properties, suggesting its potential suitability for surgical, optical, and other biomedical applications. All of the interesting features of SF, such as tunable biodegradation, anti-bacterial properties, and mechanical properties combined with potential self-healing modifications, make it ideal for future tissue engineering applications. In this review, we first demonstrate the current understanding of the structures and mechanical properties of SF and the various functionalizations of SF matrices through chemical and physical manipulations. Then the diverse applications of SF architectures and scaffolds for different regenerative medicine will be discussed in detail, including their current applications in bone, eye, nerve, skin, tendon, ligament, and cartilage regeneration. PMID:27527229

  4. Explant culture of sarcoma patients' tissue.

    PubMed

    Muff, Roman; Botter, Sander M; Husmann, Knut; Tchinda, Joelle; Selvam, Philomina; Seeli-Maduz, Franziska; Fuchs, Bruno

    2016-07-01

    Human sarcomas comprise a heterogeneous group of rare tumors that affect soft tissues and bone. Due to the scarcity and heterogeneity of these diseases, patient-derived cells that can be used for preclinical research are limited. In this study, we investigated whether the tissue explant technique can be used to obtain sarcoma cell lines from fresh as well as viable frozen tissue obtained from 8 out of 12 soft tissue and 9 out of 13 bone tumor entities as defined by the World Health Organization. The success rate, defined as the percent of samples that yielded sufficient numbers of outgrowing cells to be frozen, and the time to freeze were determined for a total of 734 sarcoma tissue specimens. In 552 cases (75%) enough cells were obtained to be frozen at early passage. Success rates were higher in bone tumors (82%) compared with soft tissue tumors (68%), and the mean time to freezing was lower in bone tumors (65 days) compared with soft tissue tumors (84 days). Overall, from 40% of the tissues cells could be frozen at early passage within <2 month after tissue removal. Comparable results as with fresh tissue were obtained after explant of viable frozen patient-derived material. In a selected number of bone and soft tissue sarcoma entities, conventional karyotyping and/or FISH (fluorescence in situ hybridization) analysis revealed a high amount (>60%) of abnormal cells in 41% of analyzed samples, especially in bone sarcomas (osteosarcoma and Ewing sarcoma). In conclusion, the explant technique is well suited to establish patient-derived cell lines for a large majority of bone and soft tissue sarcoma entities with adequate speed. This procedure thus opens the possibility for molecular analysis and drug testing for therapeutic decision making even during patient treatment. PMID:27111283

  5. [Cryopreservation of testicular tissue in children].

    PubMed

    Rives, Nathalie; Milazzo, Jean-Pierre; Travers, Albanne; Arkoun, Brahim; Bironneau, Amandine; Sibert, Louis; Liard-Zmuda, Agnès; Marie-Cardine, Aude; Schneider, Pascale; Vannier, Jean-Pierre; Macé, Bertrand

    2013-01-01

    The toxicity of cancer therapies can affect all organs and tissues. Some treatments damage spermatogonial stem cells (SSCs), with a risk of infertility. Storage and reimplantation of frozen testicular tissue is a recent approach tofertilitypreservationfor young boys. However, thawed frozen prepubertal testicular tissue must undergo a maturation process to restore sperm production. This process, currently being studied in animal models, can be achieved by in vivo transplantation of SSCs into seminiferous tubules or by testicular grafting, possibly following in vitro maturation. PMID:25518156

  6. Excursion of vibrating microelectrodes in tissue

    NASA Technical Reports Server (NTRS)

    Kanabus, E. W.; Feldstein, C.; Crawford, D. W.

    1980-01-01

    The paper deals with a vibrating microelectrode holder consisting of a support rod attached to the cone of a miniature loudspeaker. This holder facilitates a microelectrode penetration into arterial wall tissue, eliminates surface dimpling, and relieves polarographic artifacts believed to be due to tissue compression. The paper presents construction and performance details of the electrode holder, and evaluates the extent of possible damage incurred during such vibration by measuring electrode motion relative to surrounding tissue in an excised segment of femoral artery in the rabbit. It is concluded that under proper vibratory conditions microelectrodes can be easily inserted into the arterial wall with minimum tissue disturbance.

  7. Composite scaffolds for cartilage tissue engineering.

    PubMed

    Moutos, Franklin T; Guilak, Farshid

    2008-01-01

    Tissue engineering remains a promising therapeutic strategy for the repair or regeneration of diseased or damaged tissues. Previous approaches have typically focused on combining cells and bioactive molecules (e.g., growth factors, cytokines and DNA fragments) with a biomaterial scaffold that functions as a template to control the geometry of the newly formed tissue, while facilitating the attachment, proliferation, and differentiation of embedded cells. Biomaterial scaffolds also play a crucial role in determining the functional properties of engineered tissues, including biomechanical characteristics such as inhomogeneity, anisotropy, nonlinearity or viscoelasticity. While single-phase, homogeneous materials have been used extensively to create numerous types of tissue constructs, there continue to be significant challenges in the development of scaffolds that can provide the functional properties of load-bearing tissues such as articular cartilage. In an attempt to create more complex scaffolds that promote the regeneration of functional engineered tissues, composite scaffolds comprising two or more distinct materials have been developed. This paper reviews various studies on the development and testing of composite scaffolds for the tissue engineering of articular cartilage, using techniques such as embedded fibers and textiles for reinforcement, embedded solid structures, multi-layered designs, or three-dimensionally woven composite materials. In many cases, the use of composite scaffolds can provide unique biomechanical and biological properties for the development of functional tissue engineering scaffolds.

  8. Adipose tissue: cell heterogeneity and functional diversity.

    PubMed

    Esteve Ràfols, Montserrat

    2014-02-01

    There are two types of adipose tissue in the body whose function appears to be clearly differentiated. White adipose tissue stores energy reserves as fat, whereas the metabolic function of brown adipose tissue is lipid oxidation to produce heat. A good balance between them is important to maintain energy homeostasis. The concept of white adipose tissue has radically changed in the past decades, and is now considered as an endocrine organ that secretes many factors with autocrine, paracrine, and endocrine functions. In addition, we can no longer consider white adipose tissue as a single tissue, because it shows different metabolic profiles in its different locations, with also different implications. Although the characteristic cell of adipose tissue is the adipocyte, this is not the only cell type present in adipose tissue, neither the most abundant. Other cell types in adipose tissue described include stem cells, preadipocytes, macrophages, neutrophils, lymphocytes, and endothelial cells. The balance between these different cell types and their expression profile is closely related to maintenance of energy homeostasis. Increases in adipocyte size, number and type of lymphocytes, and infiltrated macrophages are closely related to the metabolic syndrome diseases. The study of regulation of proliferation and differentiation of preadipocytes and stem cells, and understanding of the interrelationship between the different cell types will provide new targets for action against these diseases. PMID:23834768

  9. Microwave-acoustic phasoscopy for tissue characterization

    NASA Astrophysics Data System (ADS)

    Gao, Fei; Zheng, Yuanjin; Wang, Dongfang

    2012-07-01

    In this letter, we present a method named microwave-acoustic phasoscopy (MAPC) by collecting both scattered microwave energy and microwave-induced thermoacoustic wave energy for tissue characterization. Different from conventional amplitude and spectrum analysis, we propose to evaluate the microwave-acoustic phase for tissue characterization. Theoretical analysis and experiment verification are performed to show a good agreement. Four different biological tissues are well differentiated in phase region using the proposed MAPC. This attempt of exploring intrinsic relationship between scattered microwave and induced thermoacoustic signals simultaneously provides phase contrast for tissue characterization, showing significant potential in developing phase-contrast imaging prototype based on MAPC theory.

  10. Mechanisms of tissue destruction following cryosurgery.

    PubMed Central

    Whittaker, D. K.

    1984-01-01

    Destruction of diseased tissue in situ by means of freezing is well established in many branches of surgery. The tissues are apparently unaltered at thaw but progressive necrosis ensues. There is controversy as to whether tissue death is principally due to the direct effects of freezing or to subsequent ischaemia. Studies at the ultrastructural level show that ice-crystals are formed within the cells during cryosurgery, that resultant cell damage is osmotic rather than mechanical and that microcirculatory changes are secondary in terms of the chronological development of tissue necrosis. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:6435496

  11. Tissue engineering principles in orthopaedic surgery.

    PubMed

    Jackson, D W; Simon, T M

    1999-10-01

    Advances in the fields of biotechnology and biomaterials offer the orthopaedic surgeon the exciting possibility of repair or regeneration of tissue lost to injury, disease, or aging. The promising area of tissue engineering represents a multidisciplinary approach aimed at solving some of the most perplexing biologic problems, namely, the creation of new tissues and organs similar to the original tissues and organs. In addition, strategies using new synthetic polymer formulations can facilitate tissue replacement and represent alternatives to tissue regeneration in certain conditions. Although biotechnology has broad application over many medical specialties, orthopaedics is receiving a large focus of the research effort devoted to techniques for developing bone, articular cartilage, ligaments, and tendons. Because bioengineered tissue and/or techniques to stimulate tissue regeneration soon may be used clinically, orthopaedic surgeons should have a working knowledge of the basic concepts involved. Terms, such as biomaterial, biotechnology, matrices of synthetic or biologic polymers or both, adhesion, cohesion, porosity, induction, conduction, stem cell, progenitor cell, mesenchymal cell, tissue growth factor, bone morphogenetic protein, mitogenic and chemotactic factors, and numerous other terms will become part of the working language of clinicians of the twenty-first century.

  12. Adipose tissue: cell heterogeneity and functional diversity.

    PubMed

    Esteve Ràfols, Montserrat

    2014-02-01

    There are two types of adipose tissue in the body whose function appears to be clearly differentiated. White adipose tissue stores energy reserves as fat, whereas the metabolic function of brown adipose tissue is lipid oxidation to produce heat. A good balance between them is important to maintain energy homeostasis. The concept of white adipose tissue has radically changed in the past decades, and is now considered as an endocrine organ that secretes many factors with autocrine, paracrine, and endocrine functions. In addition, we can no longer consider white adipose tissue as a single tissue, because it shows different metabolic profiles in its different locations, with also different implications. Although the characteristic cell of adipose tissue is the adipocyte, this is not the only cell type present in adipose tissue, neither the most abundant. Other cell types in adipose tissue described include stem cells, preadipocytes, macrophages, neutrophils, lymphocytes, and endothelial cells. The balance between these different cell types and their expression profile is closely related to maintenance of energy homeostasis. Increases in adipocyte size, number and type of lymphocytes, and infiltrated macrophages are closely related to the metabolic syndrome diseases. The study of regulation of proliferation and differentiation of preadipocytes and stem cells, and understanding of the interrelationship between the different cell types will provide new targets for action against these diseases.

  13. Ectopic lymphoid tissues and local immunity

    PubMed Central

    Carragher, Damian M.; Rangel-Moreno, Javier; Randall, Troy D.

    2008-01-01

    Ectopic or tertiary lymphoid tissues develop at sites of inflammation or infection in peripheral, non-lymphoid organs. These tissues are architecturally similar to conventional secondary lymphoid organs, with separated B and T cell areas, specialized populations of dendritic cells, well-differentiated stromal cells and high endothelial venules. Ectopic lymphoid tissues are often associated with the local pathology that results from chronic infection or chronic inflammation. However, there are also examples in which ectopic lymphoid tissues appear to contribute to local protective immune responses. Here we review how ectopic lymphoid structures develop and function in the context of local immunity and pathology. PMID:18243731

  14. Synchronous luminescence spectroscopy of human breast tissues

    NASA Astrophysics Data System (ADS)

    Majumdar, S. K.; Gupta, P. K.

    1998-06-01

    We report, to our knowledge, the first use of synchronous luminescence (SL) spectroscopy for autofluorescence diagnosis of cancer. The spectral narrowing effect of the SL spectroscopy led to an easier identification of the different fluorophores present in human breast tissues and provided relative estimate of their concentration in qualitative agreement with the estimates obtained from conventional excitation and emission spectroscopy. Further, the SL spectra from human breast tissues could discriminate cancerous tissues from benign tumors and normal tissues with a sensitivity and specificity of 100% in a study involving 34 patients with breast tumor (19 ductal carcinomas and 15 fibroadenomas).

  15. Imaging Strategies for Tissue Engineering Applications

    PubMed Central

    Nam, Seung Yun; Ricles, Laura M.; Suggs, Laura J.

    2015-01-01

    Tissue engineering has evolved with multifaceted research being conducted using advanced technologies, and it is progressing toward clinical applications. As tissue engineering technology significantly advances, it proceeds toward increasing sophistication, including nanoscale strategies for material construction and synergetic methods for combining with cells, growth factors, or other macromolecules. Therefore, to assess advanced tissue-engineered constructs, tissue engineers need versatile imaging methods capable of monitoring not only morphological but also functional and molecular information. However, there is no single imaging modality that is suitable for all tissue-engineered constructs. Each imaging method has its own range of applications and provides information based on the specific properties of the imaging technique. Therefore, according to the requirements of the tissue engineering studies, the most appropriate tool should be selected among a variety of imaging modalities. The goal of this review article is to describe available biomedical imaging methods to assess tissue engineering applications and to provide tissue engineers with criteria and insights for determining the best imaging strategies. Commonly used biomedical imaging modalities, including X-ray and computed tomography, positron emission tomography and single photon emission computed tomography, magnetic resonance imaging, ultrasound imaging, optical imaging, and emerging techniques and multimodal imaging, will be discussed, focusing on the latest trends of their applications in recent tissue engineering studies. PMID:25012069

  16. Principles, Techniques, and Applications of Tissue Microfluidics

    NASA Technical Reports Server (NTRS)

    Wade, Lawrence A.; Kartalov, Emil P.; Shibata, Darryl; Taylor, Clive

    2011-01-01

    The principle of tissue microfluidics and its resultant techniques has been applied to cell analysis. Building microfluidics to suit a particular tissue sample would allow the rapid, reliable, inexpensive, highly parallelized, selective extraction of chosen regions of tissue for purposes of further biochemical analysis. Furthermore, the applicability of the techniques ranges beyond the described pathology application. For example, they would also allow the posing and successful answering of new sets of questions in many areas of fundamental research. The proposed integration of microfluidic techniques and tissue slice samples is called "tissue microfluidics" because it molds the microfluidic architectures in accordance with each particular structure of each specific tissue sample. Thus, microfluidics can be built around the tissues, following the tissue structure, or alternatively, the microfluidics can be adapted to the specific geometry of particular tissues. By contrast, the traditional approach is that microfluidic devices are structured in accordance with engineering considerations, while the biological components in applied devices are forced to comply with these engineering presets.

  17. Visualizing enzyme infusion into apple tissue.

    PubMed

    Culver, C A; Bjurlin, M A; Fulcher, R G

    2000-12-01

    Enzymes traditionally used in food processing are applied to ground or macerated tissue with little or no retention of cellular structure. More recently developed applications use enzymes to selectively alter tissue properties while retaining some structure. Process development has been hindered by the lack of conclusive evidence showing that enzyme infusion into plant tissue pieces is possible. This study provides direct evidence that such infusion is possible by using fluorescence microscopy to monitor vacuum infusion of fluorescein-labeled alpha-amylase into apple cubes. This method is generally applicable to any plant or animal tissue and to any macromolecule capable of derivatization. PMID:11141264

  18. Microgravity cultivation of cells and tissues

    NASA Technical Reports Server (NTRS)

    Freed, L. E.; Pellis, N.; Searby, N.; de Luis, J.; Preda, C.; Bordonaro, J.; Vunjak-Novakovic, G.

    1999-01-01

    In vitro studies of cells and tissues in microgravity, either simulated by cultivation conditions on earth or actual, during spaceflight, are expected to help identify mechanisms underlying gravity sensing and transduction in biological organisms. In this paper, we review rotating bioreactor studies of engineered skeletal and cardiovascular tissues carried out in unit gravity, a four month long cartilage tissue engineering study carried out aboard the Mir Space Station, and the ongoing laboratory development and testing of a system for cell and tissue cultivation aboard the International Space Station.

  19. The organization of tissue banking in Scotland.

    PubMed

    Galea, G

    2012-11-01

    Tissue banking in Scotland has developed significantly over the past 20 years or so. The range of issues procured has increased and so have their numbers. Initially, bone from live donors was the only tissue banked; later, tissues from multiorgan donors were procured; this was finally followed by the collection of tissues from donors following cardiac death. Bones, tendons, heart valves and skin are the main tissue types collected, stored and issued for clinical use. Much of our activity is based on identification of donors in two major accident and emergency departments followed by retrievals that take place in a dedicated mortuary by fully-trained staff. Tissues are released according to clinical need for Scottish patients and beyond. All of the tissue banking activity in Scotland takes place within the Scottish National Blood Transfusion Service, which is the preferred provider of tissues for Scottish patients. There is very close cooperation between our teams, the transplant teams and other clinical colleagues, including pathologists and anatomical technicians. The achievements in issue banking in Scotland are outlined along with the main clinical indications of the tissue procured. Diversification is now taking place into cellular therapy with the establishment of an islet processing programme and cell culturing techniques. The future is very exciting.

  20. Strategies for cell engineering in tissue repair.

    PubMed

    Brown, R A; Smith, K D; Angus McGrouther, D

    1997-01-01

    Cellular and tissue engineering are new areas of research, currently attracting considerable interest because of the remarkable potential they have for clinical application. Some claims have indeed been dramatic, including the possibility of growing complete, artificial organs, such as the liver. However, amid such long-term aspirations there is the very real possibility that small tissues (artificial grafts) may be fabricated in the near future for use in reconstructive surgery. Logically, we should focus on how it is possible to produce modest, engineered tissues for tissue repair. It is evident that strategies to date either depend on innate information within implanted cells, to reform the target tissue or aim to provide appropriate environmental cues or guidance to direct cell behavior. It is argued here that present knowledge of tissue repair biology points us toward the latter approach, providing external cues which will direct how cells should organize the new tissue. This will be particularly true where we need to reproduce microscopic and ultrastructural features of the original tissue architecture. A number of such cues have been identified, and methods are already available, including substrate chemistry, substrate contact guidance, mechanical loading, and biochemical mediators to provide these cues. Examples of these are already being used with some success to control the formation of tissue structures.

  1. The dual dopamine-glutamate phenotype of growing mesencephalic neurons regresses in mature rat brain.

    PubMed

    Bérubé-Carrière, Noémie; Riad, Mustapha; Dal Bo, Grégory; Lévesque, Daniel; Trudeau, Louis-Eric; Descarries, Laurent

    2009-12-20

    Coexpression of tyrosine hydroxylase (TH) and vesicular glutamate transporter 2 (VGLUT2) mRNAs in the ventral tegmental area (VTA) and colocalization of these proteins in axon terminals of the nucleus accumbens (nAcb) have recently been demonstrated in immature (15-day-old) rat. After neonatal 6-hydroxydopamine (6-OHDA) lesion, the proportion of VTA neurons expressing both mRNAs and of nAcb terminals displaying the two proteins was enhanced. To determine the fate of this dual phenotype in adults, double in situ hybridization and dual immunolabeling for TH and VGLUT2 were performed in 90-day-old rats subjected or not to the neonatal 6-OHDA lesion. Very few neurons expressed both mRNAs in the VTA and substantia nigra (SN) of P90 rats, even after neonatal 6-OHDA. Dually immunolabeled terminals were no longer found in the nAcb of normal P90 rats and were exceedingly rare in the nAcb of 6-OHDA-lesioned rats, although they had represented 28% and 37% of all TH terminals at P15. Similarly, 17% of all TH terminals in normal neostriatum and 46% in the dopamine neoinnervation of SN in 6-OHDA-lesioned rats were also immunoreactive for VGLUT2 at P15, but none at P90. In these three regions, all dually labeled terminals made synapse, in contradistinction to those immunolabeled for only TH or VGLUT2 at P15. These results suggest a regression of the VGLUT2 phenotype of dopamine neurons with age, following normal development, lesion, or sprouting after injury, and a role for glutamate in the establishment of synapses by these neurons.

  2. Long lasting near-obstruction stenosis of mesencephalic aqueduct without development of hydrocephalus--case report.

    PubMed

    Radoš, Milan; Orešković, Darko; Radoš, Marko; Jurjević, Ivana; Klarica, Marijan

    2014-08-28

    The aim of this study is to present the five-year longitudinal magnetic resonance imaging (MRI) follow up of a patient with incidental finding of near-obstruction stenosis of the aqueduct of Sylvius due to a large pineal cyst. The patient was scanned 3 times on a 3T MR device using a set of standard structural sequences supplemented with high-resolution constructive interference of steady state (CISS) T2 sequence for precise delineation of the aqueduct of Sylvius and cardiac-gated phase-contrast sequences for the analysis of cerebrospinal fluid (CSF) movement. On all MR scans, the size of the pineal cyst and severity of near-obstruction aqueductal stenosis did not show any morphological changes. There was no significant ventricular enlargement although structural CISS sequence showed a near-obstruction stenosis and cardiac-gated phase-contrast sequences did not detect CSF movement through the aqueduct of Sylvius. Our findings are contradictory to the classic hypothesis of CSF physiology based on secretion, circulation, and absorption of CSF, which states that the impairment of CSF circulation through the aqueduct of Sylvius inevitably leads to a hypertensive hydrocephalus development involving the third and the lateral ventricle. Our research group previously proposed a new hypothesis of CSF physiology, which offers more suitable explanation for such clinical cases.

  3. Severe second-trimester obstructive ventriculomegaly related to disorders of diencephalic, mesencephalic and rhombencephalic differentiation.

    PubMed

    Cagneaux, M; Vasiljevic, A; Massoud, M; Allias, F; Massardier, J; Gaucherand, P; Guibaud, L

    2013-11-01

    By review of a series of cases, we set out to identify sonographic features suggestive of an obstructive mechanism in second-trimester fetuses with ventriculomegaly and describe developmental disorders related to pathological differentiation of the diencephalon, mesencephalon and rhombencephalon that lead to obstruction of cerebrospinal fluid flow. We studied retrospectively 11 fetuses referred for severe second-trimester ventriculomegaly of undetermined origin. Neurosonography was performed with detailed analysis of the third ventricle, thalami, cerebral aqueduct and cerebellum. The cerebral imaging data were compared with neuropathological data in eight patients, with a focus on the level and etiology of the obstruction. Parenchymal thinning and reduction of the pericerebral spaces were highly suggestive of ventriculomegaly due to an obstructive mechanism. The ventriculomegaly was related to diencephalosynapsis (thalamic fusion and third ventricle atresia) in five cases and partial/complete aqueduct stenosis in six; it was associated with cerebellar hypoplasia in six cases, including rhombencephalosynapsis in two cases. In nine patients, disorders of the diencephalon, mesencephalon and rhombencephalon were present. In cases of severe isolated ventriculomegaly in which sonographic features are suggestive of an obstructive mechanism, close examination of the third ventricle, thalami, aqueduct of Sylvius and cerebellum may reveal pathological differentiation of the diencephalon, mesencephalon or rhombencephalon, often in combination.

  4. Visualization of multiple opioid-receptor types in rat striatum after specific mesencephalic lesions

    SciTech Connect

    Eghbali, M.; Santoro, C.; Paredes, W.; Gardner, E.L.; Zukin, R.S.

    1987-09-01

    In order to gain insight into a possible modulatory role for ..mu.., delta, and kappa opioid receptors of the nigrostriatal dopaminergic pathway, the authors investigated the topographical organization of the receptors with respect to pre- and postsynaptic membranes. Dopaminergic terminals projecting from the substantia nigra to the corpus striatum were destroyed by unilateral injection of 6-hydroxydopamine into the susbstantia nigra. Quantitative receptor assays using highly specific radioligands were used to measure the density of striatal ..mu.., delta, and kappa receptors before and after denervation. Quantitative in vitro autoradiography was used to visualize the neuroanatomical pattern of receptors on lesioned and nonlesioned sides of the brain under the light microscope. Loss of ..mu.. receptors in striatal patches was striking in the ventro-lateral areas of the striatum, whereas the most notable loss of delta receptors was found in the central striatum. Other brain areas did not differ significantly in ..mu.. receptor density between the lesioned and nonlesioned sides, as determined by autoradiography. These findings suggest that a high percentage of ..mu.. and delta receptors in the striatum are located on the nigrostriatal dopaminergic terminals and support the concept of a modulatory role for ..mu.. and delta opioid peptides in the nigrostriatal dopaminergic pathway.

  5. An update on the connections of the ventral mesencephalic dopaminergic complex.

    PubMed

    Yetnikoff, L; Lavezzi, H N; Reichard, R A; Zahm, D S

    2014-12-12

    This review covers the intrinsic organization and afferent and efferent connections of the midbrain dopaminergic complex, comprising the substantia nigra, ventral tegmental area and retrorubral field, which house, respectively, the A9, A10 and A8 groups of nigrostriatal, mesolimbic and mesocortical dopaminergic neurons. In addition, A10dc (dorsal, caudal) and A10rv (rostroventral) extensions into, respectively, the ventrolateral periaqueductal gray and supramammillary nucleus are discussed. Associated intrinsic and extrinsic connections of the midbrain dopaminergic complex that utilize gamma-aminobutyric acid (GABA), glutamate and neuropeptides and various co-expressed combinations of these compounds are considered in conjunction with the dopamine-containing systems. A framework is provided for understanding the organization of massive afferent systems descending and ascending to the midbrain dopaminergic complex from the telencephalon and brainstem, respectively. Within the context of this framework, the basal ganglia direct and indirect output pathways are treated in some detail. Findings from rodent brain are briefly compared with those from primates, including humans. Recent literature is emphasized, including traditional experimental neuroanatomical and modern gene transfer and optogenetic studies. An attempt was made to provide sufficient background and cite a representative sampling of earlier primary papers and reviews so that people new to the field may find this to be a relatively comprehensive treatment of the subject. PMID:24735820

  6. Hyperthermia in soft tissue sarcoma.

    PubMed

    Lindner, Lars H; Issels, Rolf D

    2011-03-01

    Patients with high-risk soft tissue sarcomas (STS)-FNCLCC grade 2-3, size >5 cm, deep to the fascia-are at risk for developing local recurrence and distant metastasis despite surgical tumor resection. Therefore, the management of high-risk STS requires a multidisciplinary approach. Besides surgery, radiotherapy, and chemotherapy, regional hyperthermia (RHT) has the potential to become the fourth standard treatment modality for the treatment of these patients. RHT means non-invasive selective heating of the tumor area to temperatures within the range of 40-43°C for 60 min by the use of an electromagnetic heating device. Thereby RHT is always applied in addition to radiotherapy or chemotherapy or both but is not effective as a single treatment. Beside direct cytotoxicity, RHT in combination with chemotherapy enhances the drug cytotoxicity mainly by increased chemical reaction and intratumoral drug accumulation. For the neoadjuvant setting, RHT in combination with a doxorubicin- and ifosfamide-based chemotherapy has been shown to dramatically improve the tumor response rate but also prevents from early disease progression as compared to chemotherapy alone. The addition of RHT to a multimodal treatment of high-risk STS consisting of surgery, radiotherapy, and chemotherapy either in the neoadjuvant setting but also after incomplete or marginal tumor resection has been shown to significantly improve local recurrence- and disease-free survival. Based on these results and in conjunction with the low RHT-related toxicity, RHT combined with preoperative or postoperative chemotherapy should be considered as an additional standard treatment option for the multidisciplinary treatment of locally advanced high-grade STS.

  7. Amelogenin in Enamel Tissue Engineering

    PubMed Central

    2016-01-01

    In this chapter the basic premises, the recent findings and the future challenges in the use of amelogenin for enamel tissue engineering are being discoursed on. Results emerging from the experiments performed to assess the fundamental physicochemical mechanisms of the interaction of amelogenin, the main protein of the enamel matrix, and the growing crystals of apatite, are mentioned, alongside a moderately comprehensive literature review of the subject at hand. The clinical importance of understanding this protein/mineral interaction at the nanoscale are highlighted as well as the potential for tooth enamel to act as an excellent model system for studying some of the essential aspects of biomineralization processes in general. The dominant paradigm stating that amelogenin directs the uniaxial growth of apatite crystals in enamel by slowing down the growth of (hk0) faces on which it adheres is being questioned based on the results demonstrating the ability of amelogenin to promote the nucleation and crystal growth of apatite under constant titration conditions designed to mimic those present in the developing enamel matrix. The role of numerous minor components of the enamel matrix is being highlighted as essential and impossible to compensate for by utilizing its more abundant ingredients only. It is concluded that the three major aspects of amelogenesis outlined hereby – (1) the assembly of amelogenin and other enamel matrix proteins, (2) the proteolytic activity, and (3) crystallization – need to be in precise synergy with each other in order for the grounds for the proper imitation of amelogenesis in the lab to be created. PMID:26545753

  8. Self-synthesized extracellular matrix contributes to mature adipose tissue regeneration in a tissue engineering chamber.

    PubMed

    Zhan, Weiqing; Chang, Qiang; Xiao, Xiaolian; Dong, Ziqing; Zeng, Zhaowei; Gao, Jianhua; Lu, Feng

    2015-01-01

    The development of an engineered adipose tissue substitute capable of supporting reliable, predictable, and complete fat tissue regeneration would be of value in plastic and reconstructive surgery. For adipogenesis, a tissue engineering chamber provides an optimized microenvironment that is both efficacious and reproducible; however, for reasons that remain unclear, tissues regenerated in a tissue engineering chamber consist mostly of connective rather than adipose tissue. Here, we describe a chamber-based system for improving the yield of mature adipose tissue and discuss the potential mechanism of adipogenesis in tissue-chamber models. Adipose tissue flaps with independent vascular pedicles placed in chambers were implanted into rabbits. Adipose volume increased significantly during the observation period (week 1, 2, 3, 4, 16). Histomorphometry revealed mature adipose tissue with signs of adipose tissue remolding. The induced engineered constructs showed high-level expression of adipogenic (peroxisome proliferator-activated receptor γ), chemotactic (stromal cell-derived factor 1a), and inflammatory (interleukin 1 and 6) genes. In our system, the extracellular matrix may have served as a scaffold for cell migration and proliferation, allowing mature adipose tissue to be obtained in a chamber microenvironment without the need for an exogenous scaffold. Our results provide new insights into key elements involved in the early development of adipose tissue regeneration.

  9. Effects of tissue mechanical properties on susceptibility to histotripsy-induced tissue damage

    NASA Astrophysics Data System (ADS)

    Vlaisavljevich, Eli; Kim, Yohan; Owens, Gabe; Roberts, William; Cain, Charles; Xu, Zhen

    2014-01-01

    Histotripsy is a non-invasive tissue ablation method capable of fractionating tissue by controlling acoustic cavitation. To determine the fractionation susceptibility of various tissues, we investigated histotripsy-induced damage on tissue phantoms and ex vivo tissues with different mechanical strengths. A histotripsy bubble cloud was formed at tissue phantom surfaces using 5-cycle long ultrasound pulses with peak negative pressure of 18 MPa and PRFs of 10, 100, and 1000 Hz. Results showed significantly smaller lesions were generated in tissue phantoms of higher mechanical strength. Histotripsy was also applied to 43 different ex vivo porcine tissues with a wide range of mechanical properties. Gross morphology demonstrated stronger tissues with higher ultimate stress, higher density, and lower water content were more resistant to histotripsy damage in comparison to weaker tissues. Based on these results, a self-limiting vessel-sparing treatment strategy was developed in an attempt to preserve major vessels while fractionating the surrounding target tissue. This strategy was tested in porcine liver in vivo. After treatment, major hepatic blood vessels and bile ducts remained intact within a completely fractionated liver volume. These results identify varying susceptibilities of tissues to histotripsy therapy and provide a rational basis to optimize histotripsy parameters for treatment of specific tissues.

  10. A Novel Albumin-Based Tissue Scaffold for Autogenic Tissue Engineering Applications

    NASA Astrophysics Data System (ADS)

    Li, Pei-Shan; -Liang Lee, I.; Yu, Wei-Lin; Sun, Jui-Sheng; Jane, Wann-Neng; Shen, Hsin-Hsin

    2014-07-01

    Tissue scaffolds provide a framework for living tissue regeneration. However, traditional tissue scaffolds are exogenous, composed of metals, ceramics, polymers, and animal tissues, and have a defined biocompatibility and application. This study presents a new method for obtaining a tissue scaffold from blood albumin, the major protein in mammalian blood. Human, bovine, and porcine albumin was polymerised into albumin polymers by microbial transglutaminase and was then cast by freeze-drying-based moulding to form albumin tissue scaffolds. Scanning electron microscopy and material testing analyses revealed that the albumin tissue scaffold possesses an extremely porous structure, moderate mechanical strength, and resilience. Using a culture of human mesenchymal stem cells (MSCs) as a model, we showed that MSCs can be seeded and grown in the albumin tissue scaffold. Furthermore, the albumin tissue scaffold can support the long-term osteogenic differentiation of MSCs. These results show that the albumin tissue scaffold exhibits favourable material properties and good compatibility with cells. We propose that this novel tissue scaffold can satisfy essential needs in tissue engineering as a general-purpose substrate. The use of this scaffold could lead to the development of new methods of artificial fabrication of autogenic tissue substitutes.

  11. Cell Sheet-Based Tissue Engineering for Organizing Anisotropic Tissue Constructs Produced Using Microfabricated Thermoresponsive Substrates.

    PubMed

    Takahashi, Hironobu; Okano, Teruo

    2015-11-18

    In some native tissues, appropriate microstructures, including orientation of the cell/extracellular matrix, provide specific mechanical and biological functions. For example, skeletal muscle is made of oriented myofibers that is responsible for the mechanical function. Native artery and myocardial tissues are organized three-dimensionally by stacking sheet-like tissues of aligned cells. Therefore, to construct any kind of complex tissue, the microstructures of cells such as myotubes, smooth muscle cells, and cardiomyocytes also need to be organized three-dimensionally just as in the native tissues of the body. Cell sheet-based tissue engineering allows the production of scaffold-free engineered tissues through a layer-by-layer construction technique. Recently, using microfabricated thermoresponsive substrates, aligned cells are being harvested as single continuous cell sheets. The cell sheets act as anisotropic tissue units to build three-dimensional tissue constructs with the appropriate anisotropy. This cell sheet-based technology is straightforward and has the potential to engineer a wide variety of complex tissues. In addition, due to the scaffold-free cell-dense environment, the physical and biological cell-cell interactions of these cell sheet constructs exhibit unique cell behaviors. These advantages will provide important clues to enable the production of well-organized tissues that closely mimic the structure and function of native tissues, required for the future of tissue engineering.

  12. Optical Coherence Tomography in Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Zhao, Youbo; Yang, Ying; Wang, Ruikang K.; Boppart, Stephen A.

    Tissue engineering holds the promise for a therapeutic solution in regenerative medicine. The primary goal of tissue engineering is the development of physiologically functional and biocompatible tissues/organs being implanted for the repair and replacement of damaged or diseased ones. Given the complexity in the developing processes of engineered tissues, which involves multi-dimensional interactions among cells of different types, three-dimensionally constructed scaffolds, and actively intervening bioreactors, a capable real-time imaging tool is critically required for expanding our knowledge about the developing process of desired tissues or organs. It has been recognized that optical coherence tomography (OCT), an emerging noninvasive imaging technique that provides high spatial resolution (up to the cellular level) and three-dimensional imaging capability, is a promising investigative tool for tissue engineering. This chapter discusses the existing and potential applications of OCT in tissue engineering. Example OCT investigations of the three major components of tissue engineering, i.e., cells, scaffolds, and bioreactors are overviewed. Imaging examples of OCT and its enabling functions and variants, e.g., Doppler OCT, polarization-sensitive OCT, optical coherence microscopy are emphasized. Remaining challenges in the application of OCT to tissue engineering are discussed, and the prospective solutions including the combination of OCT with other high-contrast and high-resolution modalities such as two-photon fluorescence microscopy are suggested as well. It is expected that OCT, along with its functional variants, will make important contributions toward revealing the complex cellular dynamics in engineered tissues as well as help us culture demanding tissue/organ implants that will advance regenerative medicine.

  13. TISSUE REGENERATION. Inhibition of the prostaglandin-degrading enzyme 15-PGDH potentiates tissue regeneration.

    PubMed

    Zhang, Yongyou; Desai, Amar; Yang, Sung Yeun; Bae, Ki Beom; Antczak, Monika I; Fink, Stephen P; Tiwari, Shruti; Willis, Joseph E; Williams, Noelle S; Dawson, Dawn M; Wald, David; Chen, Wei-Dong; Wang, Zhenghe; Kasturi, Lakshmi; Larusch, Gretchen A; He, Lucy; Cominelli, Fabio; Di Martino, Luca; Djuric, Zora; Milne, Ginger L; Chance, Mark; Sanabria, Juan; Dealwis, Chris; Mikkola, Debra; Naidoo, Jacinth; Wei, Shuguang; Tai, Hsin-Hsiung; Gerson, Stanton L; Ready, Joseph M; Posner, Bruce; Willson, James K V; Markowitz, Sanford D

    2015-06-12

    Agents that promote tissue regeneration could be beneficial in a variety of clinical settings, such as stimulating recovery of the hematopoietic system after bone marrow transplantation. Prostaglandin PGE2, a lipid signaling molecule that supports expansion of several types of tissue stem cells, is a candidate therapeutic target for promoting tissue regeneration in vivo. Here, we show that inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a prostaglandin-degrading enzyme, potentiates tissue regeneration in multiple organs in mice. In a chemical screen, we identify a small-molecule inhibitor of 15-PGDH (SW033291) that increases prostaglandin PGE2 levels in bone marrow and other tissues. SW033291 accelerates hematopoietic recovery in mice receiving a bone marrow transplant. The same compound also promotes tissue regeneration in mouse models of colon and liver injury. Tissues from 15-PGDH knockout mice demonstrate similar increased regenerative capacity. Thus, 15-PGDH inhibition may be a valuable therapeutic strategy for tissue regeneration in diverse clinical contexts.

  14. Plant Tissue Culture in a Bag.

    ERIC Educational Resources Information Center

    Beck, Mike

    2000-01-01

    Describes the use of an oven bag as a sterile chamber for culture initiation and tissue transfer. Plant tissue culture is an ideal tool for introducing students to plants, cloning, and experimental design. Includes materials, methods, discussion, and conclusion sections. (SAH)

  15. Bioactive composite materials for tissue engineering scaffolds.

    PubMed

    Boccaccini, Aldo R; Blaker, Jonny J

    2005-05-01

    Synthetic bioactive and bioresorbable composite materials are becoming increasingly important as scaffolds for tissue engineering. Next-generation biomaterials should combine bioactive and bioresorbable properties to activate in vivo mechanisms of tissue regeneration, stimulating the body to heal itself and leading to replacement of the scaffold by the regenerating tissue. Certain bioactive ceramics such as tricalcium phosphate and hydroxyapatite as well as bioactive glasses, such as 45S5 Bioglass, react with physiologic fluids to form tenacious bonds with hard (and in some cases soft) tissue. However, these bioactive materials are relatively stiff, brittle and difficult to form into complex shapes. Conversely, synthetic bioresorbable polymers are easily fabricated into complex structures, yet they are too weak to meet the demands of surgery and the in vivo physiologic environment. Composites of tailored physical, biologic and mechanical properties as well as predictable degradation behavior can be produced combining bioresorbable polymers and bioactive inorganic phases. This review covers recent international research presenting the state-of-the-art development of these composite systems in terms of material constituents, fabrication technologies, structural and bioactive properties, as well as in vitro and in vivo characteristics for applications in tissue engineering and tissue regeneration. These materials may represent the effective optimal solution for tailored tissue engineering scaffolds, making tissue engineering a realistic clinical alternative in the near future.

  16. Nonlinear spectral imaging of biological tissues

    NASA Astrophysics Data System (ADS)

    Palero, J. A.

    2007-07-01

    The work presented in this thesis demonstrates live high resolution 3D imaging of tissue in its native state and environment. The nonlinear interaction between focussed femtosecond light pulses and the biological tissue results in the emission of natural autofluorescence and second-harmonic signal. Because biological intrinsic emission is generally very weak and extends from the ultraviolet to the visible spectral range, a broad-spectral range and high sensitivity 3D spectral imaging system is developed. Imaging the spectral characteristics of the biological intrinsic emission reveals the structure and biochemistry of the cells and extra-cellular components. By using different methods in visualizing the spectral images, discrimination between different tissue structures is achieved without the use of any stain or fluorescent label. For instance, RGB real color spectral images of the intrinsic emission of mouse skin tissues show blue cells, green hair follicles, and purple collagen fibers. The color signature of each tissue component is directly related to its characteristic emission spectrum. The results of this study show that skin tissue nonlinear intrinsic emission is mainly due to the autofluorescence of reduced nicotinamide adenine dinucleotide (phosphate), flavins, keratin, melanin, phospholipids, elastin and collagen and nonlinear Raman scattering and second-harmonic generation in Type I collagen. In vivo time-lapse spectral imaging is implemented to study metabolic changes in epidermal cells in tissues. Optical scattering in tissues, a key factor in determining the maximum achievable imaging depth, is also investigated in this work.

  17. Injectable silk foams for soft tissue regeneration.

    PubMed

    Bellas, Evangelia; Lo, Tim J; Fournier, Eric P; Brown, Joseph E; Abbott, Rosalyn D; Gil, Eun S; Marra, Kacey G; Rubin, J Peter; Leisk, Gary G; Kaplan, David L

    2015-02-18

    Soft tissue fillers are needed for restoration of a defect or augmentation of existing tissues. Autografts and lipotransfer have been under study for soft tissue reconstruction but yield inconsistent results, often with considerable resorption of the grafted tissue. A minimally invasive procedure would reduce scarring and recovery time as well as allow the implant and/or grafted tissue to be placed closer to existing vasculature. Here, the feasibility of an injectable silk foam for soft tissue regeneration is demonstrated. Adipose-derived stem cells survive and migrate through the foam over a 10-d period in vitro. The silk foams are also successfully injected into the subcutaneous space in a rat and over a 3-month period integrating with the surrounding native tissue. The injected foams are palpable and soft to the touch through the skin and returning to their original dimensions after pressure is applied and then released. The foams readily absorb lipoaspirate making the foams useful as a scaffold or template for existing soft tissue filler technologies, useful either as a biomaterial alone or in combination with the lipoaspirate.

  18. Gradient nanofiber scaffolds for tissue engineering.

    PubMed

    Seidi, Azadeh; Sampathkumar, Kaarunya; Srivastava, Alok; Ramakrishna, Seeram; Ramalingam, Murugan

    2013-07-01

    Scaffolds are one of the key factors for the success of tissue engineering, in particular when dealing with anchorage-dependent cells. The concept of using scaffolds in tissue engineering lies in mimicking the physical, chemical and biological features of native extracellular matrix (ECM) in order to support cell function, which in turn regulates cellular microenvironment that directs cell growth and subsequent tissue formation. Nanofibers fabricated from both synthetic and natural polymers are being used as scaffolds in many tissue engineering applications. At the molecular level, native ECM is made up of a gradient of fibrous proteins and polysaccharides that are nanoscale structures. The gradient cues of ECM, directs critical cell behaviors such as alignment, motility and differentiation, particularly in the region between soft and hard tissues called interfacial tissue. Therefore, it is essential to develop gradient nanofiber scaffolds particularly for interfacial tissue engineering applications. Keeping these points in view, in this article, we review the recent developments of gradient nanofiber scaffolds, their design strategies, and their applications in tissue engineering. PMID:23901487

  19. Engineering tissue with BioMEMS.

    PubMed

    Borenstein, Jeffrey T; Vunjak-Novakovic, Gordana

    2011-11-01

    In summary, microfluidic-BioMEMS platforms are increasingly contributing to tissue engineering in many different ways. First, the accurate control of the cell environment in settings suitable for cell screening and with imaging compatibility is greatly advancing our ability to optimize cell sources for a variety of tissue-engineering applications. Second, the microfluidic technology is ideal for the formation of perfusable networks, either to study their stability and maturation or to use these networks as templates for engineering vascularized tissues. Third, the approaches based on microfluidic and BioMEMS devices enable engineering and the study of minimally functional modules of complex tissues, such as liver sinusoid, kidney nephron, and lung bronchiole. This brief article highlighted some of the unique advantages of this elegant technology using representative examples of tissue-engineering research. We focused on some of the universal needs of the area of tissue engineering: tissue vascularization, faithful recapitulation in vitro of functional units of our tissues and organs, and predictable selection and differentiation of stem cells that are being addressed using the power and versatility of microfluidic-BioMEMS platforms.

  20. Cultured normal mammalian tissue and process

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas J. (Inventor); Prewett, Tacey L. (Inventor); Wolf, David A. (Inventor); Spaulding, Glenn F. (Inventor)

    1993-01-01

    Normal mammalian tissue and the culturing process has been developed for the three groups of organ, structural and blood tissue. The cells are grown in vitro under microgravity culture conditions and form three dimensional cell aggregates with normal cell function. The microgravity culture conditions may be microgravity or simulated microgravity created in a horizontal rotating wall culture vessel.