posted 07-15-2002 01:18 AM               

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MicroCHIPS, Inc. is pioneering the next generation of chemical & drug delivery devices. Our patented technology uses silicon microchips to accurately dispense medicine to the body or to deliver chemicals for use in diagnostics and biosensor applications.

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MicroCHIPS' patented technology is based on tiny silicon or polymeric microchips containing up to hundreds or thousands of micro-reservoirs, each of which can be filled with any combination of drugs, reagents, or other chemicals.

Complex chemical release patterns can be achieved by opening the micro-reservoirs on demand using preprogrammed microprocessors, remote control, or biosensors.

Potential advantages of these microchips include small size, low power consumption, absence of moving parts, and the ability to store and release multiple drugs or chemicals from a single device.

Products currently in development include external and implantable microchips for the delivery of proteins, hormones, pain medications, and other pharmaceutical compounds.

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MicroCHIPS Press Releases http://www.mchips.com/press_rel_20020520b.html

posted 09-05-2002 09:57 AM               

Use of Implanted Transponders for Permanent Identification of Reptiles and Amphibians
by Alan W. Zulich:

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Draft of manuscript published in Reptile & Amphibian Magazine. Available online with permission of the Editor.
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Introduction

Ever since reptiles and amphibians have been observed and collected in the field, there has been a need for positive identification of individual specimens. This was originally done by crude methods such as clipping of toes or caudal scales or notching shells of turtles.

As reptiles and amphibians are now present in zoos and private collections in ever increasing numbers, a need has arisen for permanent, positive identification of individual specimens.

The following article will discuss the use of Trovan transponders, small identification chips that are injected into specimens for permanent identification. The chip is read by means of a scanning gun which provides a ten-character alpha-numeric readout of the chip implanted in the animal.

Specific use of this identification system in three large private collections and one zoo will be discussed.

Why Identify Animals

There are a number of reasons for positive identification of individual animals. The first most obvious reason is for theft deterrence.

Animals in both private collections and zoos have increased dramatically in value over the past few years, and thefts of valuable specimens have been seen in both places. Use of the Trovan transponders would not only decrease the likelihood of theft, but also increase the chances of recovery of the specimen. Positive identification of animals would also help resolve insurance claims and may decrease premium costs.

The second reason for use of the transponder is for inventory control. TheTrovan system has now been internationally recognized as the identification system of choice for animal collections.

Zoos throughout the world are incorporatingTrovan ID systems into their animal databases such as ISIS. At their recent meeting in Japan, the Convention on International Trade in Endangered Species (CITES) named the Trovan system for use when specimens are shipped internationally.

Another reason is for positive identification within a collection. Animals are now being bred in captivity in record numbers. Some animals such as the brown water python (Liasis fuscus) are unicolored and patternless, making it very difficult to visually identify individual specimens when housed as a group.

The Trovan system will permit this identification without physically disturbing the animal. The same can be true for the field herpetologist, especially when a large number of animals must be individually identified.

The Trovan system would be particularly attractive to breeders working with legal, protected animals. As a particular example, the private reptile breeders in Florida are quite anxious to work with their native species, especially the eastern indigo snake, Drymarchon c. couperi.

To date there have been strong reservations by the state wildlife management people that, especially with the indigo, there is no way to distinguish a legal, captive-produced specimen from a wild-caught individual. This identification system may go a long way in resolving the issue.

Captive-bred specimens could be registered with the Florida Game and Fresh Water Fish Commission, along with the implanted identification number. As the transponder is virtually impossible to falsify, it would be relatively easy to verify the origin of animals in collections.

The system also permits identification safely, with minimal stress to the animal. As the identification is passive, the implanted chips can be read from a distance of over a foot and in many cases, right through the cage glass. Thus, the animal identification can be verified without even opening a cage, a plus when working with dangerous species or nervous animals.

Finally, as the captive-breeding industry is rapidly expanding, it is advantageous from both the buyer and seller's points of view to have animals positively identified. This is especially true when a significant amount of money is paid for animals heterozygous for albinism. If the animals should prove to be normal rather than heterozygous, a positive identification system would be essential for the settlement of potential disputes.

The Trovan System

The transponder consists of a wire-wound glass-encapsulated chip, about the size of two grains of rice laid end-to-end. These chips come from the supplier pre-loaded into a 8-10 gauge hypodermic needle. Using an insertion tool very similar in appearance to a syringe, the chip is injected either subcutaneously or interperitoneally into the animal. Location of injection site varies with type of animal. Barker and Barker (pers comm., 1990) performed a comparative anatomy study of various species of pythons and concluded that the area approximately twenty ventral scales before the anal plate poses least risk of interference with vital organs.

For the study, we chose that site and injected the chip subcutaneously at the junction of the ventral and lateral scales. For their large snakes, the Columbus Zoo has chosen the dorsal muscle mass in the same location on the body. Turtles have also been injected intraperitoneally, with the injection site just anterior to a hindlimb.

To date, over 600 reptiles have been implanted at the three private collections and the Columbus Zoo, without a single injury noted.

The Trovan transponders themselves are quite inexpensive. The cost is approximately $10.00 per chip, pre-loaded in its needle in a sterile individual package. Thus, it would cost approximately $30.00 for a veterinarian to implant an individual animal. Implantation of a number of animals at a time should decrease this cost.

The chips are then read with a device resembling a hand hair dryer. The "gun" is pointed at the individual specimen and, as the tag is read, a ten character alpha- numeric code is displayed on the gun. In this configuration, over a billion combinations are possible, virtually eliminating the possibility of duplication or falsification. This reading is done in a totally passive mode, providing no danger or discomfort to the animal.

The reader gun is relatively expensive, retailing at approximately $500, but purchase of the gun is not necessary to attain the benefits of this system, as many zoos and wildlife management organizations already have them. Since they would not be in constant use except in very large collections, it may be worthwhile for regional herpetological societies or groups of private collectors to pool resources to purchase one.

Summary

The Trovan transponders have been evaluated in both private and zoo reptile collections and found to be a safe and reliable means to permanently identify animals. Potential benefits of this system are theft deterrence, pedigree assessment and verification of legal protected animals. It is strongly recommended for zoo collections, and its low cost makes it within reach of the serious hobbyist.

posted 09-07-2002 11:21 PM               

Camera in the eye could help the blind to see again

By Roger Highfield, Science Editor
(Filed: 07/09/2002)

Enabling the blind to see - a task once thought the province of miracles - is the goal of an ambitious £6 million programme launched by the United States government.

A team of scientists is working on a device, consisting of a tiny camera and radio transmitter lodged in the frame of a patient's spectacles to transmit information and power to modules placed within the eyeball.

The modules will be linked to retinal nerves that will send electrical impulses to the brain for processing.

Diseases such as age-related macular degeneration and retinitis pigmentosa damage the rods and cones in the eye that normally convert light to electrical impulses, but leave intact the nerve pathways to the brain.

Eventually the input from rods and cones ceases, but up to 90 per cent of nerve structures set up to receive their signals remain intact.The team aims to create 1,000 points of light through 1,000 minute electrodes positioned on the retinas of those blinded by diseases.

Counterintuitively, the rods and cones of the retina lie beneath nerves, not above them, which makes connecting the device easier.

The team, which includes Sandia National Laboratories, New Mexico, four other national labs, a private company and two universities, has been funded by the Department of Energy's Office of Biological and Environmental Research.

"The aim is to bring a blind person to the point where he or she can read, move around objects in the house, and do basic household chores," said Sandia project leader Kurt Wessendorf. "They won't be able to drive cars, at least in the near future, because instead of millions of pixels, they'll see approximately one thousand. The images will come a little slowly and appear yellow. But people who are blind will see."

The silicon chip should be able to stimulate directly some of the nerve endings within the retina to produce images good enough to read large print and to distinguish between objects in a room.

"Compared to the elegance of the original biological design, what we're doing is extremely crude," concedes Mr Wessendorf. "We are trying to build retinal implants in the form of electrode arrays that sit on the retina and stimulate the nerves that the eye's rods and cones formerly served."

The plan is to achieve a 10-by-10 electrode array this year and 33-by-33 arrays by 2004.

Mike Daily, manager of Sandia, said there were several hurdles to overcome. These include how to make devices that will work in a saline environment; cope with protein fouling that can upset delicate interfaces intended to transmit electrical impulses; how to cope with rejection; and long-term reliability.

Over a five-year period, the project will begin with goggles and move in the direction of corneal implants, aiming, if all goes well, to prepare five patients for implants.

The project began in February when Prof Mark Humayun, of the University of Southern California implanted a permanent retinal prosthesis known as the "eye chip" in a patient as part of a trial.

The 4mm by 5mm chip is studded with 16 electrodes in a 4-by-4 array. "Each electrode can excite a lot of nerve cells," said Prof Humayun.

posted 09-24-2002 10:16 AM               

Experts Try to Make Bionic Retinas

By RANDOLPH E. SCHMID

ASSOCIATED PRESS

WASHINGTON- Attempts to restore sight to people with damaged retinas are turning toward signaling the brain the way nature does it, using chemicals to deliver signals to nerve endings. Experiments already under way with retinal implants seek to use electrical signals to make the nerves send information to the brain. But doctors from Michigan and California described a different method Monday, using retinal implants that respond to images by releasing nerve-stimulating chemicals.

Dr. Raymond Iezzi of Wayne State University and Dr. Harvey A. Fishman of Stanford University discussed their separate research projects at a science writers seminar on ophthalmology.

Neither is close to testing the idea in people.

Both indicated animal experiments may be a year away.

Nerves carry messages to or from the brain by electrical impulses, but nerves are stimulated to send those signals by chemicals generated by organs or relayed from other nerve endings.

About half of all blindness is a result of damage to the retina, the inner part of the eye containing cells that react to light by releasing chemicals that cause the optic nerve to send signals to the brain.

Experiments using an electronic chip implanted in the retina, sending an electric current to stimulate the optic nerve, are in early stages. But, instead of direct electrical signals, Fishman and Iezzi turned their attention, in slightly different ways, to the chemicals that the body uses to get those nerves to send signals.

Iezzi's research is focusing on a retinal implant that can deliver what he calls an array of "chemical pixels" through tiny holes, somewhat like a very small, gentle, inkjet printer or shower head, stimulating nerves to relay an image to the brain.

There are several neurotransmitter chemicals and Iezzi is using glutamate in his tests. He said the final product may use a cocktail of these chemicals.

As he envisions it, the chip would receive a supply of neurotransmitters from a reservoir under the skin behind the ear. It would react to signals from a small digital camera, perhaps worn like an eyeglass.

"Once we prove the basic concept, we can go on and refine the design," he said.

Fishman is developing what he calls an artificial synapse chip, an implant that also would deliver minute amounts of chemical transmitters. But in his case, the chip is designed to direct the growth of nerve cells into tiny openings in the chip where they can be stimulated by the release of chemicals in response to light.

The chemicals are held within the chip.

Fishman said his team is working on ways to get the nerve cells to grow into the chip.

Experiments with a carpet of carbon tubes have been promising, he said: "This gives us a lot of hope that in animals we can direct the process."

The two spoke at a conference sponsored by the New York-based organization, Research to Prevent Blindness.

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On the Net: Research to Prevent Blindness: www.rpbusa.org