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SUMMARY: Vascular Cast Materials

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  • SUMMARY: Vascular Cast Materials

    On 1/24 I wrote:

    I trying to locate a material to make casts of vascular structures.
    I've seen some used in the past; one is more latex-like, the other
    more acrylic-like. Ideally they should have viscosities that are
    similar to blood so extreme pressures don't distort the geometry.
    Also a protocol for digestion of the tissue that reveals the vascular
    structure would be of help. I've seen pictures of a vascular network
    cast placed over the bones of a joint, and would like to be able to
    something similar.

    Thanks to all who replied!
    A summary of replies follows:

    REPLY #1 -----------------------------------------------------------

    I don't know the name or source of this material, but one of my former
    teachers, Dr. Michael LaBarbera at The University of Chicago uses it
    regularly. You can reach him at mlabarbe@midway.uchicago.edu

    sharon swartz

    ************************************************** ****
    Sharon Swartz
    Department of Ecology and Evolutionary Biology Box G-B206
    Brown University
    Providence, RI 02912
    USA

    phone: 401-863-1582 (office)
    401-863-3549 (lab)
    401-863-7544 (fax)

    e-mail: sharon_swartz@brown.edu
    ************************************************** ****

    REPLY #2 -----------------------------------------------------------

    Hi:

    One of the team of the University of Washington Engineered
    Biomaterials (UWEB) program (J&J is a member) has developed what I
    believe to be an
    excellent protocol to do want you want. I'll put you in
    touch by e-mail with Professor Karyn Kunzelman for details. If you'd
    like to learn more about UWEB, e-mail me and I'll send you some
    literature.

    Buddy Ratner
    University of Washington

    Karyn Kunzelman replied:

    Yes, we have done this in our laboratory, and Jane Grande is one of my
    students who has had the most experience with this. We used a
    silicone based resin to cast the structures, then dissolved the tissue
    away with bleach. I mentioned your request to her, and she told me
    that she had e-mailed some information to you. If you have not
    received the specs on the silicone, etc., from Jane please let me
    know. In addition, I would be happy to talk to you and provide futher
    info, as I have done it here and in another lab in Dallas with a
    different product.

    Jane Grande's reply follows immediately:

    REPLY #3 -----------------------------------------------------------

    Hello,

    I have used silicone rubber to create vascular casts. The type I used
    was GE Silicones RTV-11 which is quite viscous but can be diluted with
    silicone oil to make it easier to handle. The cure time for the
    silicone rubber was about 4 hours although this may vary with the
    amount of oil you add. In the past we have used generic bleach to
    dissolve the tissue surrounding the casts.

    Good luck!
    Jane Grande
    __________________________________________________ _______________
    Jane Grande
    --grande@u.washington.edu--http://weber.u.washington.edu/~grande
    Bioengineering Doctoral Student, University of Washington
    206-543-3159 off Cardiothoracic Surgery, Box 356310, Seattle WA
    98195-6310 206-543-0325 fax

    Never let your sense of morals prevent you from doing what is right!
    - Salvor Hardin (Isaac Asimov)


    REPLY #4 -----------------------------------------------------------

    There are silicone dental impression materials that can be purchased
    in a syringe type application system. These are fairly low viscosity
    for silicone materials. Unfortunately, I do not know the name of the
    manufacturer of this material. I would guess that the diameter of the
    vien will be the limiting factor for the viscosity in terms of
    distortion of the viens.

    You could formulate a low viscosity silicone and put some TiO2 filler
    in it to make it opaque if one of the commercial formulations is
    unsuitable. Contact me if you need help with formulating a suitable
    material.

    Hank Oviatt

    POSTER'S COMMENTS:
    I've tried dental impression materials manufactured by Kerr [Mfg (313)
    946-7800, Eng (800) 537-7824], and purchased through our local dental
    or vet supply house. I comes in four viscosities (Wash, Medium,
    Heavy, and Putty). I have found them great: they set up fast, capture
    very fine detail, and do not have to be degassed. However, for my
    application the set-up is a little too fast and the viscosity of the
    wash is still a little high.

    REPLY #5 -----------------------------------------------------------

    John,

    I've had pretty good luck making vascular casts using the standard
    Batson's #17 corrosion casting compound (acrylic). Its made by
    Analychem and distributed by Polysciences or vice versa - if you need
    more exact information, I can
    look it up for you. Its more viscous than blood, but rather than using
    extreme pressures and distorting the geometry, I use mean physiological
    pressure but don't get all the small sub-branches (I get nice casts in
    rabbit tissues down
    to quite a bit less than 1mm diameter though, so depending on what
    you're after, that might be adequate). I believe
    there are other versions of Batson's which are more/less viscous.

    You might try a literature search for work by Fred Cornhill and also
    Margo Roach who have done a lot of work
    in this field--if you can't find anything and are interested, I can
    probably dig up the references for you.

    As for tissue digestion, once you have polymerized your casting
    material in situ, cut out the cast (including surrounding tissue as
    necessary) and just leave it all in a 20% solution
    of KOH overnight--the KOH will dissolve away the tissue leaving your
    cast intact.

    Good luck!

    Jennifer Moore
    Department of Mechanical Engineering University of Toronto
    Toronto, Canada
    mooreja@me.utoronto.ca

    POSTER'S COMMENTS: The dental casting materials mentioned earlier
    (polyvinylsiloxane) seem to be only semi compatable with tissue
    digestion in KOH. The surface can be left soft and tacky.

    REPLY #6 -----------------------------------------------------------

    Dear sir,

    In reply to your question on casting of cardiovascular struc- tures,
    we contacted our colleagues of anatomy. They are using two techniques:

    1. Solution of:
    Araldite F 8 ml
    .6 g Microlith-T (colour choice green, blew, black, yellow and brown)
    24 ml Dilutioner DY 026 SP
    18 ml Hardener HY 2967
    These materials can be obtained from Ciba Geigy.

    2. Silicon technique:
    Elastosil M 4601 A 9 parts
    Elastosil M 4601 B 1 part
    Colour pigment Fl D Red or blew 0.5-2%
    These materials are obtained from a local Dutch Company


    C.M.Ligtvoet
    Biomedical Engineering Department
    University Hospital Utrecht
    The Netherlands

    send by:
    L.J. van Schelven
    University Hospital Utrecht
    Biomedical Engineering Department
    F 01.125
    P.O. Box 85500
    NL-3508 GA Utrecht
    The Netherlands

    tel. +31 30 2506198
    fax. +31 30 2542002


    Thanks again to all those who replied!
    ================================================== ====================
    John F. Cummings
    Ethicon Endo-Surgery JCumming@EESUS.JNJ.COM
    4545 Creek Rd. V: (513) 483-3370
    Cincinnati, OH 45242 F: (513) 483-8285
    ================================================== ====================
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