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Thursday, 19 October, 2000, 15:52
GMT
McRae's oxygen cure
From : http://news.bbc.co.uk/
Hyperbaric chambers are used to help
stricken divers Rally driver Colin McRae is reputed to have used a
pressurised oxygen treatment to speed his recovery from injury.
McRae suffered a fractured cheekbone in a
horrifying crash during the Rally of Corsica, just a few weeks ago.
However, he could be fit to drive again in the
San Remo rally on October 20 - and his hours spent lying in a tank
breathing high pressure oxygen may have helped achieve this.
This therapy, called hyperbaric medicine, was
first developed to help divers who had fallen prey to "the bends", a
potentially fatal condition caused by ascending through the water
too quickly.
The rapid rise cause large bubbles of nitrogen
to form in the blood – if left untreated, these can kill.
Scientists discovered that by placing divers in
a pressurised chamber and making them breathe 100% oxygen, instead
of the 21% found in normal air, a cure could be achieved.
The increased pressure - up to three times
atmospheric pressure, compresses the bubbles of nitrogen and forces
some to dissolve back into the blood.
Other conditions
And the pure oxygen also seems to be able to
flush out the nitrogen from the bloodstream.
However, in recent years, doctors have become
more and more aware of the potential of hyperbaric medicine in other
medical conditions.
Dr Stephen Watt, who treats patients at the
Aberdeen Royal Infirmary, said that 100% oxygen delivered at above
atmospheric pressure appeared to be able to reduce inflammation in
certain damaged tissues – speeding up the healing process.
If the damage had been caused by an
interruption of the proper blood supply, such as in the case of open
wounds, burns or frostbite, some sessions in the chamber might be
able to help.
Dr Watt said: "There is some evidence that
oxygen interferes with this inflammatory process, and may help
reduce some of the side effects – it will accelerate healing."
Much research has concentrated on applications
in diabetes, where problems with the blood and oxygen supply to
tissues can lead to ulcers which heal slowly, or do not heal at all.
One study looking at the recovery of facial
bones after the insertion of implants found the normal recovery rate
of 65 to 70% boosted to over 90% by hyperbaric therapy.
Poisonous
Oxygen may keep us alive, but it is not without
its risks as a treatment, and 100% oxygen is actually poisonous,
particularly at high pressures, which mean the body absorbs more.
So patients can only spend a few hours a time
having treatment.
The treatment can take more than one form.
If the patient is quite ill, and needs
supervision by a nurse, then it may take place in a large metal
chamber in which the air is pressurised, and the patient given the
extra oxygen by facemask.
There are also solo treatment chambers, which
can be made out of perspex, and are completely filled with
high-pressure oxygen.
However, Dr Watt says these may not be
suitable for all patients - adding that the fire risk of large
quantities of pressurised oxygen is not inconsiderable.
The Importance of Glial Cells
HBOT brings dissolved oxygen to the glial level
that is important in treating brain damage. HBOT helps redistribute
blood to the non-ischemic areas around the lesions, preventing these
areas from being harmed. These areas are generally affected by the
response of the brain to injury which is a vasoconstriction, making
them more susceptible to ischemic damage also, thereby continuing to
spread the damage beyond its original area. HBOT prevents this
stealing" of blood, reducing intra cranial pressure and raising
tissue oxygen flow.
For more information,
The role of Hyperbaric-Oxygen Therapy for intra
cranial pathology in Intensive Care.
Glial cells are important and preventing their
damage is necessary.
Lowly Glia Strengthen Brain Connections
STANFORD -- Once dismissed as
mere padding, cells known as glia may be essential for the correct
wiring of the brain. This is the conclusion of a study reported in
the Sept. 12 issue of Science by researchers from the Stanford
University School of Medicine.
Postdoctoral fellow Frank Pfrieger and Dr.
Barbara Barres, associate professor of neurobiology, used pure
populations of nerve cells and glia to show that, by themselves, the
nerve cells connected together poorly, but the combination of the
two cell types resulted in strong connections between nerve cells.
In the brain, such connections allow nerve
cells to pass along messages about our every sensation, thought and
movement.
Glia make up approximately 90 percent of the cells in
the human brain, and yet researchers have assigned mainly passive
functions to them. Some glia wrap around nerve cells and insulate
them with a protein called myelin. Glia at synapses act both as a
physical barrier that prevents crossed wires and as a disposal unit
that mops up extra messenger molecules released by nerve cells.
The nerve cells chosen for the Stanford study
-- retinal ganglion cells -- lead from the eyes deep into the brain.
Barres is using them as representatives of a large class of nerve
cells in the brain: those that use a chemical messenger called
glutamate to send a positive, or excitatory, signal.
It is also possible, she said, that glia
control the strength of synapses in the fully developed brain,
beefing up some circuits and turning down others.
For more information on the above, see: Lowly
Glia Strengthen Brain Connections.
There are five types of glial
cells:
*Oligodendroglia, which provide the
insulation (myelin) to neurons in the central nervous system.
*Schwann Cells, which provide the insulation (myelin) to neurons
in the peripheral nervous system.
- *Astrocyte (Astroglia), star-shaped cells that provide
physical and nutritional support for neurons:
to clean up
brain "debris";
- To transport nutrients to neurons;
- To hold neurons in place;
- To digest parts of dead neurons;
- To regulate content of extra cellular space
*Microglia, which like astrocytes,
digest parts of dead neurons.
*Satellite Cells, which provide
physical support to neurons in the peripheral nervous system
For more information, see
Glia; The Forgotten Brain Cell. |