 Housing system for a laser |
| OF A PREFERRED EXAMPLE EMBODIMENT AND OF THE BEST MODE OF THE INVENTION A conventional wave-guide ... |
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| Cryogenic infrared laser in deuterium |
| In accordance with this invention, an infrared laser in deuterium is provided that lases in the 4 .... |
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| Method of bonding two parts together and article produced thereby |
| OF THE INVENTION Referring to FIG. 1, there is shown one form of an article, generally designated ... |
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| Semiconductor device |
| It is, therefore, an object of the present invention to eliminate the above-described problems. It ... |
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| Overdrive control of FET power amplifier |
| I claim: 1. In combination: a FET power amplifier including a gate electrode; an overdrive control ... |
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| Magnetic display panels |
| OF THE PREFERRED EMBODIMENTS Referring now to the drawing by numerals of reference and first to FIG... |
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| Method of making compensated collinear reading or writing bar arrays assembled from subunits |
| An object of the present invention is to provide a large array fabrication process that will permit ... |
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| Dielectric barrier material |
| The present invention comprises a method of fabricating an integrated circuit. A substrate ... |
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| Method of joining beam leads with projections to device electrodes |
| It is, accordingly, a primary object of this invention to provide a method of manufacturing a ... |
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Hydrated biodegradable superparamagnetic metal oxides
| Details |
Inventors: Groman, Ernest V.; Josephson, Lee; Lewis, Jerome M.;
Assignee: Advanced Magnetics, Inc. (Cambridge, MA)
Primary Examiner: Rosenbaum; C. Fred
Assistant Examiner: Stright, Jr.; Ronald K.
Attorney, Agent or Firm: Pennie & Edmonds
This invention relates to materials exhibiting certain magnetic and biological properties which make them uniquely suitable for use as magnetic resonance imaging (MRI) agents to enhance MR images of animal organs and tissues. More particularly, the invention relates to the in vivo use of biologically degradable and metabolizable superparamagnetic metal oxides as MR contrast agents. Depending on their preparation, these metal oxides are in the form of superparamagnetic particle dispersoids or superparamagnetic fluids where the suspending medium is a physiologically-acceptable carrier, and may be uncoated or surrounded by a polymeric coating to which biological molecules can be attached. These materials are administered to animals, including humans, by a variety of routes and the metal oxides therein collect in specific target organs to be imaged; in the case of coated particles, the biological molecules can be chosen to target specific organs or tissues. The biodistribution of the metal oxides in target organs or tissues results in a more detailed image of such organs or tissues because the metal oxides, due to their superparamagnetic properties, exert profound effects on the hydrogen nuclei responsible for the MR image. In addition, the dispersoids and fluids are quite stable and, in the case of the fluids, can even be subjected to autoclaving without impairing their utility. Furthermore, the materials are biodegradable and, in the case of iron oxide compounds, can eventually be incorporated into the subject's hemoglobin, making them useful in treating anemia. Thus, the materials are well-suited for in vivo use. |
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DETAILED DESCRIPTION OF THE INVENTION 1.
Preparation of Coated Superparamagnetic Iron Oxide Particles The synthesis of superparamagnetic iron oxide particles for use as MRI contrast agents is accomplished by mixing ferrous and ferric salts with base to form a black, magnetic oxide of iron.
Crystals result from such precipitations, for when the material is subjected to X-ray diffraction analyses long range order is apparent.
A diameter of between about 50 and about 300 angstroms for such crystals has been calculated although crystals may range in diameter from about 10 to about 500 angstroms.
The iron oxides have correspondingly high surface areas, greater than about 75 m.
sup.
2 /gm.
The presence of ferrous salts prior to base addition insures the formation of a black, crystalline magnetic iron oxide.
Without the ferrous ion, paramagnetic ferric oxide gels (noncrystalline materials) result (as described e.
g.
, in U.
S.
Pat.
No.
2,885,393).
The presence of divalent iron, so essential to the formation of the superparamagnetic material, can then be removed by exposure of the material to oxidizing conditions.
Oxidation of the iron to produce a ferric oxide after formation of the crystal does not alter the usefulness of the material as a contrast agent in MRI or the superparamagnetism.
It is to be understood throughout this detailed description, that the use of superparamagnetic iron oxides as MR contrast agents is but one embodiment of the invention and that superparamagnetic oxides of other magnetic metals, e.
g.
, cobalt or gadolinium, may be substituted for iron oxides.
There are two general strategies for the formation of the coated superparamagnetic iron oxide particles suitable for MRI.
1.
Synthesis of iron oxide by precipitation in the presence of polymers like dextran, or polyglutaraldehyde or other material.
Such syntheses include those described by London et al.
, U.
S.
Pat.
No.
2,870,740, Molday, U.
S.
Pat.
No.
4,452,773, Cox et al.
, Nature, 208, 237 (1965) and Rembaum, U.
S.
Pat.
No.
4,267,234; all of which are incorporated herein by reference
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Quantum Computing 
