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VOLUME 11, NUMBER 1 JUNE, 1985 SVM Researcher Studies Regeneration Research Provides Clues to Spinal Cord Trauma and Fracture Healing Have you ever wondered why some animals can regenerate a limb or a tail, while others cannot? Or what the specific mechanisms are which prevent most paraplegics from regaining full use of their legs? Richard B. Borgens, Ph.D., has been pondering these questions since childhood, and is now studying them on a full-time basis at the Purdue University School of Veterinary Medicine. Dr. Borgens investigates the role of the natural flow of electricity common in all developing and regenerating tissues, finding clues to the nature of wound-healing and tissue regeneration, as well as embryonic development and cell differentiation. Wounds of any sort produce an electrical field adjacent to the lesion, and a weak, steady flow of electric current out of the wound, Dr. Borgens said. For example, when the limb of a salamander is amputated, Dr. Borgens, and others, have fuund and measuied an electrical cuneni leaving the stump and returning to the undamaged portions of the limb and body. This current steadily declines until disappearing upon the appearance of new limb growth. Whereas the amputation of an adult salamander's limb may initiate limb regeneration, Borgens' research indicates that a developmentally programmed "wound" may initiate limb generation in salamander larvae. Upon finding a small increase in current along the flank of a larva, Dr. Borgens has been able to pinpoint the location at which a limb bud will form. In salamanders, according to Dr. Borgens, skin is the electromotive force which drives electric current out of the regenerating limb stump or out of presumptive limb regions and developing buds. Indeed, if a skin flap is sewn over the face of the limb stump, limb regeneration is inhibited. Among chordates, regenerative ability is thought to have reached its peak in the tailed amphibians, such as salamanders. However, Dr. Borgens has found that mice can regrow the tip of a foretoe when it has been amputated distal to the last joint. And, in humans, especially children, regrowth of the tips of fingers has been reported after accidental amputation. If the finger is severed somewhere between the last joint and nail, a nearly perfect replacement may regrow within a few months, often complete with nail and fingerprint. However, the attending physician must not sew the finger closed, for if closed, no regrowth will occur. The natural flow of current, similar in most respects to that leaving salamander limb stumps, has been measured leaving the finger stumps of children and foretoe studied certain regrowth mechanisms in the lamprey, a small, primitive vertebrate with giant neurons. Upon transection of its spinal cord, a lamprey has the natural ability to eventually regenerate neurons across the lesion, restoring its ability to swim. However, Dr. Borgens has found that a weak, steady electrical current imposed across the severed spinal cord speeds the regeneration of neurons up to and across the lesion. In addition to laboratory animal models, working in the Veterinary Medical School may provide Dr. Borgens the opportunity to study spontaneously-occurring spinal injuries in small companion animals. Es- Ongoing research in Dr. Borgens' lab tests whether an applied electrical field can Induce substantial amounts of nerve regeneration within the mammalian spinal cord. stumps of mice. In addition, Dr. Borgens said the regeneration of amphibian limbs and the regrowth of the mammalian digits share at least two other similarities. First, the level of amputation is critical. Second, a skinflap sewn over the stump inhibits both the regeneration of amphibian limbs and the regrowth of human fingertips. "But we're not in the business just to grow limbs back on animals and people," Dr. Borgens said. Dr. Borgens has also pecially common in basset hounds and dachshunds, these injuries could provide information needed to further understand spinal injuries in humans. Dr. Borgens is now involved in the next step: applying electric current to the spinal cord of small laboratory mammals to try to initiate regeneration. So far, Dr. Borgens said, the results are promising. Outgrowths of other's electrophysiologic research include the clinical use of electricity to speed regeneration of various tis- A surgically implanted battery imposes an electrical field across a hemisected guinea pig spinal cord. sues in animals and humans. For example, adhesive bandages and casts with built-in electrodes are presently being tested. In addition, electricity is sometimes used to help treat persons with chronic non-union bone fractures. If several bone grafts or pins fail to produce union, then sometimes a portion of the limb must be amputated. However, two different types of electrical stimulating devices, both approved by the U. S. Food and Drug Administration, are now increasing the success rate in such cases. Dr. Borgens has found that bone is an electrically dynamic tissue, driving a steady electric current into the site of injury after a fracture. According to Dr. Borgens, the healing potential of artificially applied electric current probably resides in its action on the natural electrical mechanisms already present in growing and healing bone. A Texan, Dr. Borgens received the doctorate in developmental biology and biophysics in 1976 from Purdue under the direction of embryologist, Lionel F. Jaffe. Before returning to Purdue in 1982, Dr. Borgens worked in laboratories on both the east and west coasts. Laura L. Voss, M.A. - . ^ * A regenerating neuron within a transected guinea pig spinal cord. The spear shaped ending with a tuft is called the growth cone. Search For New Dean Begins Dean Jack Stockton has announced his intention to retire as dean in December of this year. President Beering has appointed a Search Committee to recommend candidates for the deanship. Members of the Search Committee are Drs. William Blevins, Gerald Bottoms, John Fessler, Kenneth Meyer, Ralph Richardson, David Van Sickle, John Van Vleet, all representing the School; Vice President Struther Arnott, Graduate School; Professor William Fuller, University Senate; Dean Bernard Liska, Agriculture; Ms. Lynda Rhodes, 3rd year student; and Dr. Robert Ferguson, alumnus. The committee has been meeting regularly and has begun to shorten the long list of potential candidates. Your comments to the committee will be welcomed at any time.
Object Description
Title | Purdue University veterinary medical update, 1985, v. 11, no. 1 (June) |
Subjects (MeSH) |
Veterinary Medicine Education, Veterinary |
Creators | Purdue University. School of Veterinary Medicine |
Purdue Identification Number | PSVM00111 |
Subjects (LCSH) | Veterinary medicine--Study and teaching (Higher) |
Genre | Periodical |
Coverage | United States |
Date of Original | 1985 |
Type | text |
Format | JP2 |
Collection Title | SVM Report |
Repository | Purdue University Libraries |
Language | eng |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Date Digitized | 2009-08-06 |
Digitization Information | Original scanned at 300 ppi on a Bookeye 3 scanner using Bookeye 3 internal software, with 24 bit color depth. Display images generated in CONTENTdm as JP2000s; file format for archival copy is uncompressed TIF format. |
URI | ark:/34231/c600002c |
Description
Title | page 1 |
Subjects (MeSH) |
Veterinary Medicine Education, Veterinary |
Creators | Purdue University. School of Veterinary Medicine |
Subjects (LCSH) | Veterinary medicine--Study and teaching (Higher) |
Genre | Periodical |
Coverage | United States |
Type | text |
Format | JP2 |
Collection Title | SVM Report |
Repository | Purdue University Libraries |
Language | eng |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Digitization Information | Original scanned at 300 ppi on a Bookeye 3 scanner using Bookeye 3 internal software, with 24 bit color depth. Display images generated in CONTENTdm as JP2000s; file format for archival copy is uncompressed TIF format. |
Transcript | VOLUME 11, NUMBER 1 JUNE, 1985 SVM Researcher Studies Regeneration Research Provides Clues to Spinal Cord Trauma and Fracture Healing Have you ever wondered why some animals can regenerate a limb or a tail, while others cannot? Or what the specific mechanisms are which prevent most paraplegics from regaining full use of their legs? Richard B. Borgens, Ph.D., has been pondering these questions since childhood, and is now studying them on a full-time basis at the Purdue University School of Veterinary Medicine. Dr. Borgens investigates the role of the natural flow of electricity common in all developing and regenerating tissues, finding clues to the nature of wound-healing and tissue regeneration, as well as embryonic development and cell differentiation. Wounds of any sort produce an electrical field adjacent to the lesion, and a weak, steady flow of electric current out of the wound, Dr. Borgens said. For example, when the limb of a salamander is amputated, Dr. Borgens, and others, have fuund and measuied an electrical cuneni leaving the stump and returning to the undamaged portions of the limb and body. This current steadily declines until disappearing upon the appearance of new limb growth. Whereas the amputation of an adult salamander's limb may initiate limb regeneration, Borgens' research indicates that a developmentally programmed "wound" may initiate limb generation in salamander larvae. Upon finding a small increase in current along the flank of a larva, Dr. Borgens has been able to pinpoint the location at which a limb bud will form. In salamanders, according to Dr. Borgens, skin is the electromotive force which drives electric current out of the regenerating limb stump or out of presumptive limb regions and developing buds. Indeed, if a skin flap is sewn over the face of the limb stump, limb regeneration is inhibited. Among chordates, regenerative ability is thought to have reached its peak in the tailed amphibians, such as salamanders. However, Dr. Borgens has found that mice can regrow the tip of a foretoe when it has been amputated distal to the last joint. And, in humans, especially children, regrowth of the tips of fingers has been reported after accidental amputation. If the finger is severed somewhere between the last joint and nail, a nearly perfect replacement may regrow within a few months, often complete with nail and fingerprint. However, the attending physician must not sew the finger closed, for if closed, no regrowth will occur. The natural flow of current, similar in most respects to that leaving salamander limb stumps, has been measured leaving the finger stumps of children and foretoe studied certain regrowth mechanisms in the lamprey, a small, primitive vertebrate with giant neurons. Upon transection of its spinal cord, a lamprey has the natural ability to eventually regenerate neurons across the lesion, restoring its ability to swim. However, Dr. Borgens has found that a weak, steady electrical current imposed across the severed spinal cord speeds the regeneration of neurons up to and across the lesion. In addition to laboratory animal models, working in the Veterinary Medical School may provide Dr. Borgens the opportunity to study spontaneously-occurring spinal injuries in small companion animals. Es- Ongoing research in Dr. Borgens' lab tests whether an applied electrical field can Induce substantial amounts of nerve regeneration within the mammalian spinal cord. stumps of mice. In addition, Dr. Borgens said the regeneration of amphibian limbs and the regrowth of the mammalian digits share at least two other similarities. First, the level of amputation is critical. Second, a skinflap sewn over the stump inhibits both the regeneration of amphibian limbs and the regrowth of human fingertips. "But we're not in the business just to grow limbs back on animals and people," Dr. Borgens said. Dr. Borgens has also pecially common in basset hounds and dachshunds, these injuries could provide information needed to further understand spinal injuries in humans. Dr. Borgens is now involved in the next step: applying electric current to the spinal cord of small laboratory mammals to try to initiate regeneration. So far, Dr. Borgens said, the results are promising. Outgrowths of other's electrophysiologic research include the clinical use of electricity to speed regeneration of various tis- A surgically implanted battery imposes an electrical field across a hemisected guinea pig spinal cord. sues in animals and humans. For example, adhesive bandages and casts with built-in electrodes are presently being tested. In addition, electricity is sometimes used to help treat persons with chronic non-union bone fractures. If several bone grafts or pins fail to produce union, then sometimes a portion of the limb must be amputated. However, two different types of electrical stimulating devices, both approved by the U. S. Food and Drug Administration, are now increasing the success rate in such cases. Dr. Borgens has found that bone is an electrically dynamic tissue, driving a steady electric current into the site of injury after a fracture. According to Dr. Borgens, the healing potential of artificially applied electric current probably resides in its action on the natural electrical mechanisms already present in growing and healing bone. A Texan, Dr. Borgens received the doctorate in developmental biology and biophysics in 1976 from Purdue under the direction of embryologist, Lionel F. Jaffe. Before returning to Purdue in 1982, Dr. Borgens worked in laboratories on both the east and west coasts. Laura L. Voss, M.A. - . ^ * A regenerating neuron within a transected guinea pig spinal cord. The spear shaped ending with a tuft is called the growth cone. Search For New Dean Begins Dean Jack Stockton has announced his intention to retire as dean in December of this year. President Beering has appointed a Search Committee to recommend candidates for the deanship. Members of the Search Committee are Drs. William Blevins, Gerald Bottoms, John Fessler, Kenneth Meyer, Ralph Richardson, David Van Sickle, John Van Vleet, all representing the School; Vice President Struther Arnott, Graduate School; Professor William Fuller, University Senate; Dean Bernard Liska, Agriculture; Ms. Lynda Rhodes, 3rd year student; and Dr. Robert Ferguson, alumnus. The committee has been meeting regularly and has begun to shorten the long list of potential candidates. Your comments to the committee will be welcomed at any time. |
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