U.S. patent application number 10/637205 was filed with the patent office on 2004-08-26 for method for increasing tissue oxygenation.
This patent application is currently assigned to Hydron Technologies, Inc.. Invention is credited to Fox, Charles, McGrath, Terrence S..
Application Number | 20040166171 10/637205 |
Document ID | / |
Family ID | 23011998 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040166171 |
Kind Code |
A1 |
McGrath, Terrence S. ; et
al. |
August 26, 2004 |
Method for increasing tissue oxygenation
Abstract
Disclosed are methods and compositions for increasing tissue
oxygen levels by administration of superoxygenated compositions of
tissue surfaces. The methods are applicable to treatment of a wide
variety of conditions including burns, bedsores, ulcers, necrosis
and anaerobic infections.
Inventors: |
McGrath, Terrence S.; (Boca
Raton, FL) ; Fox, Charles; (Fair Lawn, NJ) |
Correspondence
Address: |
AKERMAN SENTERFITT
P.O. BOX 3188
WEST PALM BEACH
FL
33402-3188
US
|
Assignee: |
Hydron Technologies, Inc.
Pompano Beach
FL
|
Family ID: |
23011998 |
Appl. No.: |
10/637205 |
Filed: |
August 8, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10637205 |
Aug 8, 2003 |
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10052075 |
Jan 18, 2002 |
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6649145 |
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60265819 |
Feb 1, 2001 |
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Current U.S.
Class: |
424/600 |
Current CPC
Class: |
A61P 31/04 20180101;
A61P 11/00 20180101; A61P 1/02 20180101; A61P 15/02 20180101; A61P
17/02 20180101; A61K 33/00 20130101; A61P 17/00 20180101 |
Class at
Publication: |
424/600 |
International
Class: |
A61K 033/00 |
Claims
What is claimed is:
1. A method of increasing tissue oxygenation in mammals, comprising
applying a superoxygenated composition to a tissue surface for a
time sufficient to increase the subepithelial partial oxygen
pressure from about 30% to about 120% above baseline pO.sub.2.
2. The method of claim 1 wherein the mammal is a human.
3. The method of claim 1 wherein the tissue is skin.
4. The method of claim 1 wherein the tissue is affected by a
medical condition.
5. The method of claim 4 wherein the medical condition is selected
from the group consisting of bedsores, wounds, bums, and
ulcers.
6. The method of claim 4 wherein the medical condition is a
bacterial infection.
7. The method of claim 6 wherein the bacterial infection is
identified as an anaerobic pathogen bacterial infection.
8. The method of claim 1 wherein the superoxygenated composition is
applied to a site selected from the group consisting of a mucosal
surface and the surface of an organ.
9. The method of claim 8, wherein the organ is one that has been
removed from an animal donor.
10. The method of claim 1 wherein the superoxygenated composition
comprises from about 45 ppm oxygen to about 220 ppm oxygen.
11. The method of claim 1 wherein the superoxygenated composition
is at about 0.degree. C. to about 34.degree. C.
12. The method of claim 1 wherein the superoxygenated composition
comprises a pharmaceutically acceptable vehicle.
13. The method of claim 1 wherein the superoxygenated composition
comprises water and oxygen microbubbles.
14. The method of claim 13 wherein the oxygen microbubbles are
between about 2.mu. and about 10.mu. in diameter.
15. The method of claim 13 wherein the microbubbles are between
about 0.6.mu. and about 5.mu. in diameter.
16. The method of claim 13 wherein the superoxygenated composition
is applied under agitation.
17. The method of claim 16 wherein the agitation is provided in a
whirlpool bath.
18. The method of claim 1 wherein the composition is applied in a
cream, lotion or gel.
19. The method of claim 1 wherein the composition is applied by
soaking, immersion, spraying, rubbing or aerosols.
Description
[0001] This application claims the priority of U.S. patent
application Ser. No. 10/052,075 filed Jan. 18, 2002 and of U.S.
provisional patent application Serial No. 60/265,819 filed Feb. 1,
2001, the entire contents of each are hereby incorporated by
reference.
1.0 BACKGROUND ART
[0002] 1.1 Field of the Invention
[0003] The present invention is directed to oxygenating
compositions and methods for administering high levels of oxygen to
subcutaneous and subepithelial tissues. In particular, methods for
surface delivery of super oxygenating compositions for such
treatment are described.
[0004] 1.2 Description of the Related Art
[0005] In many medical conditions including diabetes, bums,
bedsores, and wounds the ability to oxygenate tissue is compromised
and arterial oxygen may not reach damaged skin. Tens of thousands
of patients die each year in the U.S. as a result of complications
from insufficient delivery of oxygen to compromised tissue. Poor
oxygen delivery, particularly in the limbs, results in slow
healing, infections, scar development, and in the worst cases,
tissue death and amputation.
[0006] The effect of oxygen tension on wound healing has been
extensively studied. (For a review, see Whitney, J. D. (1989)).
Wound healing is dependent upon several processes including
proliferation of fibroblasts, collagen synthesis, angiogenesis and
re-epithelialization. Animal studies have shown that several of
these processes are affected by the subcutaneous partial pressure
of oxygen (pO.sub.2). For example, supplemental oxygen can lead to
increased rate of collagen deposition, epithelialization and
improved healing of split thickness grafts. Increased subcutaneous
pO.sub.2 has also been shown to improve bacterial defenses.
[0007] Many skin sores, ulcers, wounds and bums do not heal
properly because there is a severe depletion of oxygen reaching
these affected areas due to deterioration of the associated blood
microcirculation. Conventionally, many of these skin diseases have
been treated by various methods of administration of oxygen gas,
either through inhalation of the gas, or by topical treatment with
the gas.
[0008] The oldest method of administering oxygen gas to a patient
is by hyperbaric chamber technology. This is a systemic treatment,
involving placement of a patient in a closed pressurized chamber.
Inside the chamber, the patient breathes elevated levels of oxygen
gas. The extra oxygen taken in by inhalation becomes dissolved in
the bloodstream and diffuses into the body tissues, thereby raising
the local tissue oxygen levels. Unfortunately, hyperbaric treatment
has not been successful in all situations, in particular where
trauma or disease restrict blood flow to the affected tissue.
Treatment of skin diseases by placing a patient in a hyperbaric
chamber is costly and time-consuming and many patients react
unfavorably when placed in hyperbaric chambers. Treatment of many
conditions, such as bedsores, for much longer than four hours at
one time may induce oxygen toxemia and hence be counterproductive.
Toxic effects of hyperbaric treatment include twitching, ringing in
the ears, dizziness, and in some cases severe effects such as coma
and convulsions. Additionally, hyperbaric treatment is expensive
and only available in treatment facilities that are properly
equipped with hyperbaric chambers. Patients are only given oxygen
through the lungs. The atmosphere of a multichamber hyperbaric unit
is ordinary atmospheric gas as there is little known therapeutic
value assigned to topical application of oxygen.
[0009] To overcome drawbacks associated with systemic hyperbaric
treatment, attempts have been made to use "topical hyperbaric"
oxygenation devices designed for regional use on an isolated body
part such as a limb. In such devices, the delivery route for the
pressurized oxygen is topical, as opposed to systemic. Only the
affected body part is exposed to the pressurized oxygen. Thus the
oxygen gas must diffuse from the surface of the skin to the
underlying tissues. For example, U.S. Pat. No. 4,801,291 discloses
a portable topical hyperbaric apparatus having a gas impermeable
internal chamber into which therapeutic gases are introduced to
treat a portion of the patient's body. Similarly, U.S. Pat. No.
5,020,579 discloses a hyperbaric oxygenation apparatus in which a
limb is isolated in a portable chamber in the form of an inflatable
bag into which oxygen gas is administered through an oxygen port in
communication with a patient respirator connected to an oxygen
source. The pressure of the oxygen in the collapsible bag is
pulsated between maximum and minimum positive values. The patient
cyclically experiences first an increase in the blood gas levels on
the limb under treatment with a corresponding restriction in blood
flow and, thereafter, a progressive return to normal blood flow
rates in the limb as the pressure in the chamber changes from
maximum to minimum positive pressure.
[0010] Several disadvantages exist with the approach of using
"topical hyperbaric" oxygenation devices. For example, an external
oxygen source and a respirator normally used for respiratory
therapy must be supplied with the apparatus. In addition,
intermittent restriction and release of blood flow to the treatment
area may not be advisable or tolerable for already compromised
tissues.
[0011] Alternative topical methods to "topical hyperbaric"
treatments for poorly healing skin lesions involve the topical
application of high levels of oxygen gas through wound dressings.
U.S. Pat. No. 5,792,090, discloses an oxygen generating wound
dressing and a method of increasing oxygen tension in surface
wounds through the application of such a bandage. In this method,
the wound dressing contains an oxygen permeable membrane and a
reservoir capable of supplying oxygen through a chemical reaction.
U.S. Pat. No. 5,855,570 describes another type of oxygen-producing
bandage to promote healing of skin wounds. This device combines a
wound dressing with an electrochemical, chemical, or thermal means
of generating high purity oxygen, and can be regulated to supply
oxygen gas to an area above the wound at various concentrations,
pressures and dosages.
[0012] Unfortunately, topical treatments with oxygen gas such as by
topical hyperbaric oxygenation and use of oxygen bandages have
provided only minor improvements in promoting healing of skin
disorders and in treating diseases. Moreover, peroxide application
can generate singlet oxygen O.sub.2 and is a potential source of
free radical damage to the skin (Elden, 1995).
1.3 DEFICIENCIES IN THE PRIOR ART
[0013] Administration of elevated levels of systemic oxygen gas has
been recognized as beneficial in the treatment of several skin
disorders; however, the available delivery methods, such as
hyperbaric chamber therapy, topical application of oxygen gas,
topical hyperbaric treatment of isolated limbs and use of
oxygen-producing bandages are at best minimally effective and often
lead to problems that include toxicity and poor oxygen penetration
of the skin. Currently used procedures for treatment of skin
disorders such as ulcers, bedsores, and burns may exacerbate the
existing skin disorder.
[0014] It is therefore desirable to provide methods of treatment
for skin disorders that increase tissue oxygenation to induce more
rapid healing of the skin, while not exacerbating an existing
condition or causing additional side effects.
2.0 SUMMARY OF THE INVENTION
[0015] Conventional methods of increasing tissue oxygenation employ
oxygen gas. In distinct contrast, the present invention discloses a
novel method of increasing tissue oxygenation by topical
application of a superoxygenated composition. The superoxygenated
compositions rapidly raise oxygen partial pressure levels in the
tissue by promoting efficient diffusion of oxygen into the
tissue.
[0016] Accordingly, the invention discloses a method of increasing
tissue oxygenation in mammals, comprising applying a
superoxygenated composition to a tissue surface for a time
sufficient to increase the subepithelial partial oxygen pressure
from about 30% to about 120% above baseline pO.sub.2. The mammal
will generally be a human, but there is no limitation to its use in
veterinary applications to small and large animals that may have
tissue damage responsive to therapeutic procedures that increase
oxygenation of tissues.
[0017] The most common applications are direct application to the
external skin but the method is equally applicable to mucous
membrane surfaces of the alimentary canal as well as organ
surfaces. Organs may be exposed or actually removed from the body
cavity during surgical procedures. One may immerse an organ in a
superoxygenated solution prepared in accordance with the invention,
contact part of the organ with such a preparation, or perfuse the
organ with the superoxygenated solution. In the latter case, this
may be an ex vivo procedure intended to maintain organ viability
and reduce ischemic damage.
[0018] One may desire to increase the oxygen level in tissues for
several reasons, mainly in situations where the tissue is affected
by a condition or disease such as bedsores, wounds, bums or ulcers
or any condition that tends to decrease normal tissue oxygen
levels. Additionally, It is expected to be particularly beneficial
in treating anaerobic bacterial infections such as those caused by
Pseudomonas species, Bacteroides species such as Bacteroides
fragilis, Prevotella melaninogenica, Prevotella bivia, Prevotella
disiens, Fusobacterium, Actinomyces, Lactobacillus,
Propionibacterium, Eubacterium, Bifidobacterium, Arachnia,
Peptostreptococcus, Veillonella, Clostridium species such as C.
tetani, C. botulinum, C. perfringens, C. difficile and
Porphyromonas. These infections may fester internally in lung
tissue, oral or vaginal mucosa or become embedded in the surface of
organs such as liver, kidney and heart.
[0019] Accordingly, one of the benefits of using the disclosed
methods to enhance tissue oxygen levels is the toxicity to
pathogenic anaerobic bacteria. A particularly desirable application
is to control or kill the anaerobic bacteria responsible for
peridontal disease. A superoxygenated mouthwash solution would be
safe and convenient for use and can be packaged to maintain
stability of the superoxygenated solution by using a pressurized
container with means for single dose dispensing or packaged for
single use.
[0020] The superoxygenated compositions of the present invention
comprise at least about 55 ppm oxygen but find useful
concentrations from about 45 to about 220 ppm. The oxygen level in
the compositions depends on several factors, including the type of
composition, the temperature, and other components, active or not,
that may be added for various reasons such as stability, ease of
application or to enhance absorption.
[0021] It is well known that gas concentration in fluids will be
inversely proportional to the temperature. When desiring to use
aqueous based superoxygenated compositions, the temperature will be
dictated not by chemical considerations but by the potential damage
to living tissue and by the need for higher oxygen concentrations.
Accordingly, where the compositions are applied locally to external
skin surfaces; for example to a forearm lesion, solution
temperatures of about 0.degree. C. will generally be considered
appropriate. This will provide relatively high oxygen levels,
typically in the range of 220 ppm. On the other hand, a patient may
be whole-body immersed in a whirlpool bath at a more comfortable
temperature in the range of about 34.degree. C. The oxygen
concentration will necessarily be less than 220 ppm due not only to
temperature but also to the open environment commonly used in
whirlpool baths in such establishments as rehabilitation
centers.
[0022] The superoxygenated solutions and compositions of the
present invention comprise oxygen microbubbles. Conventionally
pressurized liquids such as carbonated beverages contain relatively
large gas bubbles that escape fairly quickly into the atmosphere
once pressure is released. The microbubbles employed in the
disclosed compositions are much smaller, remain in solution longer
and are thus more stable. Importantly, the oxygen provided by the
microbubbles is at a partial pressure effective to quickly raise
subepithelial oxygen partial pressure significantly above baseline
or normal oxygen partial pressure levels.
[0023] As generated for use in the disclosed superoxygenated
compositions, microbubble size is typically in the 1-2 micron
range. The small size is believed to be an important contributor to
the beneficial effects of topical application of solutions
containing the microbubbles. The most preferred solutions appear to
be those in which the oxygen bubbles are no larger than about 8
microns in size; however, a range of microbubble sizes exist in the
prepared solutions, at least as small as 0.6 microns as detected at
the limit of resolution by impedence methods for which results are
illustrated graphically in FIG. 3. A practical range for many
applications is between about 1 .mu. and about 10 .mu. in diameter
or between about 3.mu. and about 8.mu. in diameter.
[0024] While the microbubble compositions need not be purely
aqueous, compositions will normally comprise an aqueous base such
as a buffer, or a pharmaceutically acceptable vehicle that will not
be harmful if in contact with a tissue surface. Buffers, if
employed, are preferably in the physiological pH range of 7.2-7.4
but may also be at lower pH such as provided by acetate buffers or
at a higher pH in more alkaline buffers such as carbonate buffer.
For many applications the superoxygenated compositions will
comprise water and oxygen microbubbles.
[0025] It may be beneficial in some circumstances to provide
agitation to the superoxygenated composition while it is being
applied to the tissue. This will increase oxygen contact to the
tissue surface and may increase efficiency of uptake. Agitation is
inherent in the method of application when the compositions are
part of a whirlpool bath treatment and may compensate somewhat for
some decrease of oxygen in an open atmosphere environment and use
of temperatures that are intended to provide patient comfort.
[0026] The oxygen supersaturated compositions of the invention may
be applied in a variety of ways depending on the area to be
applied, the nature of the condition and, for treatment purposes,
the health condition of the subject or patient to be treated. Skin
treatments will typically be applied as solutions that may be
incorporated into creams, pastes, powders, ointments, lotions or
gels or simply superoxygenated microbubble preparations in
nonaqueous or aqueous media. An important consideration will be the
concentration of microbubbles in the preparation and its ability to
increase subepithelial partial oxygen pressure.
[0027] The method of application to the skin may be by soaking,
immersion, spraying, rubbing or aerosols. The preparations may be
applied to dressings that are in contact with the skin, such as
plasters and wound coverings. In other applications, douches or
enemas may be used for vaginal or rectal administration. Selection
of the method will depend on particular patient needs, the area of
application and type of equipment available for application.
[0028] Superoxygenated compositions are another aspect of the
invention. The composition comprises an aqueous-based solution of
oxygen microbubbles having a diameter of from about 0.6 micron to
about 100 microns and having an oxygen concentration between about
45 ppm and about 220 ppm. Preferred embodiments include
superoxygenated compositions where the microbubble diameter ranges
from about 0.6 to about 5 microns and compositions where the
microbubble diameter is about 5 to about 8 microns. A highly
preferred superoxygenated composition includes microbubbles of
oxygen in the range of 1-2 microns.
[0029] While liquid microbubble superoxygenated compositions will
be preferred in most applications, the compositions may be in solid
or frozen form. In aqueous based solutions this may be as low as
-40.degree. C. but could be as low as -70.degree. C. in frozen
gases such as carbon dioxide or in liquified gases such as
nitrogen. These low temperatures are not practical for applications
to living tissue; however, long term storage of certain cells or
other biological material may benefit from this type of
environment. In any event, there are several applications of
superoxygenated aqueous solids in providing for example a slow
release oxygen environment or where ice might be in contact with
excised organs being transported for transplant purposes.
[0030] The compositions and methods disclosed may be combined in an
apparatus for the purpose of providing a tissue oxygenating
environment to a mammal in need of increased tissue oxygenation. An
apparatus may include a container for holding an at least 55 ppm
superoxygenated aqueous solution produced from an oxygen generating
machine connected to the container. The apparatus may further
include additional features for more efficient and convenient use,
such as devices to agitate the superoxygenated composition being
applied. In a particular embodiment, the device may induce a
whirlpool effect. The device may be a sonicator to provide more
effective distribution of microbubbles and which may help to
maintain high oxygen levels in the solution. Stirrers, shakers,
bubblers and the like may also be used to provide mixing.
[0031] The apparatus may also include a temperature controller that
may be useful in controlling the oxygen levels in the
superoxygenated solutions. An additional effect may be to enhance
oxygen uptake through the skin of some subjects due to an increase
in skin surface temperature. For use with patients, one may prefer
to adjust temperatures to between about 37.degree. C. and about
45.degree. C.
[0032] In a particular application, the methods and compositions
may be used to treat anaerobic infections. Generally this will
involve applying any of the aforementioned compositions to a skin
lesion suspected of harboring anaerobic bacteria. The method should
be particularly effective against the anaerobic bacteria typically
found in gangrenous or ulcerated tissue. Such anaerobic bacteria
are also found in wound infections. Patients are likely to benefit
from increased tissue oxygen in the wound area. Burned skin areas
are particularly susceptible to infection, particularly where
tissue is destroyed or badly damaged as in second and third degree
burns. Burn patients are expected to benefit from such treatment
that can be used prophylactically as well as therapeutically. Other
conditions that will benefit from increased tissue oxidation
include the soft tissue in the oral cavity, particularly in
treating gum disease that is usually caused by anaerobic
bacteria.
[0033] For convenience, kits may be used to package various
superoxygenated compositions prepared in accordance with the
invention. An exemplary kit with appropriate instructions for use
in topically increasing tissue oxygenation may contain a sealed
permeable flexible container and a containerized superoxgenated
composition in one or more of the variations described. The kits
may additionally include a whirlpool generating device, and/or a
thermostat/heating device for adjusting temperature inside the
container.
[0034] As discussed, the disclosed methods employ application of a
superoxygenated composition to a surface for a time sufficient to
increase the subepithelial tissue partial oxygen pressure
(pO.sub.2) from about 30% to about 120% above baseline pO.sub.2
levels. The method is applicable particularly to humans who suffer
from such conditions as tissue necrosis, bedsores, ulcers, bums or
anaerobic infection.
[0035] The present invention addresses several of the problems
encountered in attempts to develop therapies and treatments that
increase topical availability of oxygen to tissues, particularly to
the skin. Skin conditions, such as ulcers, bedsores, wounds, burns,
and other serious dermatological problems may be treated by
utilizing an aqueous solution charged with oxygen microbubbles
applied directly to the skin. An important application is scar
reduction where treatment may be used subsequent to scarring or on
wounds, burns or surgical incisions to reduce scar formation. The
methods are also applicable to increasing oxygen levels in infected
surface tissues such as puncture wounds and soft tissue infections
of the oral cavity.
[0036] It is well known that many types of skin sores, ulcers,
wounds and burns do not heal properly because there is a severe
depletion of oxygen reaching these affected areas due to
degeneration or damage of the associated blood microcirculation.
The human skin is at the terminus of the oxygen delivery system and
exhibits signs of oxygen loss in a variety of pathological
conditions. Degeneration of skin tissue is largely due to oxygen
deprivation. Although the skin is exposed to the atmosphere, only a
negligible amount of oxygen is actually absorbed. Increasing the
level of oxygen absorbed by the skin directly results in increased
healing rates of the skin.
[0037] The present invention utilizes a method of tissue
superoxygenation that provides oxygen to tissue to aid in its
healing and revitalization. Oxygen is provided to the tissue
through microscopic bubbles and is present at a pressure many times
that found in blood. The oxygen in the microbubbles can be
transported through the skin when placed in contact with the skin.
Such treatment increases the oxygen level in the interstitial
fluids of the subepithelial and dermal tissues and is immediately
available to the oxygen-depleted cells, thereby inducing more rapid
healing. The disclosed procedures will aid in the prevention of
gangrene formation and treatment of sepsis, decrease the need for
amputations in diabetic patients, and help to heal bedsores, skin
lacerations, burns and wounds. This type of treatment is more
convenient to use and is much more affordable than existing methods
of treatment for these conditions, such as a hyperbaric
chamber.
[0038] The methods are useful not only in prevention of several
skin disorders but also in cosmetic and pharmaceutical
applications. Of particular interest to many teenagers and even
adults are formulations that will benefit healthy skin while also
promoting healing of common acne, a skin condition that may be
disfiguring to a certain degree.
[0039] Superoxygenated compositions may also benefit victims
suffering from smoke inhalation and damage from inhaled hot air. In
such cases, the disclosed superoxygenated compositions are
administered directly to the lung in order to increase oxygen
concentration to the damaged cells. Such treatment may also be used
to wash inhaled particulates from the lungs and can be administered
in conjunction with antibiotic and anti-inflammatory drug solutions
where indicated. The superoxygenated fluid can be used as a spray
or intubated as a soaking solution to provide more controlled
contact with the internal surface of the lung.
[0040] In like manner, internal injuries such as bullet wounds may
benefit from being flushed with the superoxygenated fluids herein
disclosed. This will be particularly useful for deep wounds where
surgery is not indicated or in field situations where access to the
wound is difficult. In such cases, the wound is flushed with the
disclosed compositions to inhibit anaerobic infection and to
provide supplemental oxygen to damaged tissue.
[0041] The superoxygenated compositions are typically aqueous
solutions of oxygen microbubbles with diameters from about 0.1 to
about 10 microns, preferably about 1 to about 8 microns and more
preferably at least about 0.6 to about 8 microns with oxygen
concentrations from about 45 ppm to about 220 ppm. In most
applications the solutions will include microbubbles with a range
of sizes, including less than 0.6 microns up through
1,2,3,4,5,6,7,8, 9 and 10 microns and may contain larger
microbubble sizes as microbubbles coalesce, depending on
temperature. Of course the oxygen concentration will depend on the
temperature of the liquid, typical oxygen concentrations being up
to about 220 ppm at 2.degree. C. or about 118 ppm at 34.degree. C.
These concentrations may be varied depending on the condition of
the tissue surface to be treated, the type of tissue and the
location of the tissue surface.
[0042] In special applications considerably higher oxygen
concentrations may be desired; for example, well above 220 ppm.
This may be achieved by preparing solutions of oxygen nanobubbles
as small as 20-30 nanometers such as those described in association
with flowing liquids across hydrophobic surfaces (Tyrrell and
Attard, 2001). Nanobubbles are thought to be flat rather than round
and to form closely packed, irregular networks that nearly
completely cover hydrophobic surfaces. They appear to reform
quickly after being distributed and are therefore quite stable.
Regardless of how nanobubbles are produced, it is likely that
concentrations of oxygen significantly higher than 250 ppm may be
attained and will be useful in achieving high tissue oxygenation
levels.
[0043] Oxygen microbubbles may be prepared in water or in a
pharmaceutically acceptable vehicle. Physiological saline, various
buffers, or compounds that increase wetting and porosity are
examples of composition variations. In some cases, one may wish to
add antibiotics, anti-inflammatory compounds or other drugs to the
compositions in order to expedite healing or more effectively treat
certain bacterial infections.
[0044] In certain applications, it may be desirable to administer
superoxygenated compositions in the form of creams, lotions, gels
or solids. Such formulations are well recognized and accessible to
those skilled in the art. The superoxygenated compositions may also
be maintained in a frozen state, for example for storage, or for
use in treatments where ice can be conveniently applied to a tissue
surface so that higher levels of oxygen can be consistently
maintained. In a particularly important application, frozen or
chilled superoxygenated compositions may be used for storage and
transport of organs intended for transplantation. This may avoid or
ameliorate anoxic conditions arising from severance of the organs
from the normal blood supply. Frozen or chilled compositions will
be especially beneficial for such tissues, both because enzymatic
processes are retarded at the lower the temperature, and because at
lower temperatures, higher levels of oxygen can be incorporated
into the oxygenated compositions so that degradation is
inhibited.
[0045] The superoxygenated compositions may be administered in
several ways such as through tubes connected to flexible bags
containing superoxygenated solution or in some applications by
immersion of tissue in a bath containing the oxygenated solution.
For dental applications in treating gum disease, administration by
a device similar to a water pic is an effective method for
topically administering suitable superoxygenated solutions. Certain
applications benefit from mixing or agitating procedures so that
fresh solution constantly bathes the tissue; for example, lavage
procedures or whirlpool baths in which an affected limb is
immersed.
[0046] In certain embodiments, an apparatus for providing a tissue
oxygenating environment to a mammal in need of increased tissue
oxygenation is also within the scope of the invention. Such an
apparatus incorporates a machine for generating oxygen microbubbles
that may be as simple as an oxygen cylinder connected to a
pressurized vessel at pressures in the range of 90-110 psi and
introducing oxygen gas into the vessel that holds a liquid such as
water or other suitable water-based fluid. An oxygenator may also
be used, generating about 50 psi. A tube or other exit from the
vessel provides the oxygenated solution to the target tissue.
Oxygen levels in the solution may be increased by agitating or
sonicating the vessel. Ultrasonic equipment external to the flow
intake and adaptations to control diffusion patterns in a vessel or
a bath may also be employed.
[0047] It will be appreciated also that solution temperature will
affect total oxygen concentration so that in alternative
embodiments, the apparatus may incorporate any of a number of well
known devices for controlling temperature such as thermostatted
baths. Thus where applications are whole limb or body applications
in open air as in a whirlpool bath, oxygen concentrations will not
usually exceed about 55 ppm. For treatment of an internal
epithelial lining, as in oral mucosal infections, cooler
temperatures and correspondingly higher oxygen concentrations will
be tolerable. Oxygen concentrations will vary depending on the
method of application whether by soaking, immersion, spraying,
rubbing or aerosols; however, in any event, the compositions
contacting the affected tissue will have a significantly increased
oxygen concentration in the range of at least about 45 ppm.
[0048] While most applications will utilize aqueous solutions, the
inventors do not wish to be unduly limited since high oxygen
concentrations may be achieved in nonaqueous or aqueous/organic
solvents. Such solvents should be non-toxic and pharmacologically
acceptable for human use. Perfluorocarbons are a particular example
of non-aqueous solvents that might be useful. Other solvents
include those that are water-miscible such as alcohols and glycols.
In certain applications it may be convenient to use gel
formulations such as hydrophilic gels formulated from alginates or
carrageenans.
[0049] Other embodiments include kits that conveniently provide
some form of the apparatus described above and will be useful for
topically increasing tissue oxygenation. Exemplary kits may include
a sealed permeable flexible container containing a superoxygenated
composition and instructions for applying the composition to the
tissue surface or skin requiring increased oxygenation. Optional
kit components include a thermostat/heating device for adjusting
temperature inside the container and an oxygen supply connectable
with a pressurized vessel for mixing, agitating or sonicating an
oxygenated fluid.
3.0 BRIEF DESCRIPTION OF THE DRAWINGS
[0050] The drawings form part of the present specification and are
included to further demonstrate certain aspects of the present
invention. The invention may be better understood by reference to
one or more of the following drawings in combination with the
detailed description of specific embodiments presented herein:
[0051] FIG. 1 Illustrates oxygen release to cells
[0052] FIG. 2A Illustrates a cross-sectional view of normal skin.
Arrows show normal direction of diffusion of oxygen from
capillaries into dermis and overlying epidermis.
[0053] FIG. 2B Illustrates a cross-sectional view of abnormal skin.
The superoxygenated composition of the invention is applied to the
surface of the skin; arrows indicate direction of movement of
oxygen through the epidermis and into the underlying subcutaneous
tissues.
[0054] FIG. 3 Shows the size distribution of microbubbles in the
superoxygenated composition.
[0055] FIG. 4 Shows measurements of subcutaneous pO.sub.2 levels in
pig skin, indicating rapid diffusion of oxygen through the skin
following topical application of oxygen microbubbles. Topical
application of control solution had no effect.
[0056] FIG. 5 Shows comparison of pO.sub.2 increase and skin
temperature, indicating increase in pO.sub.2 following topical
application of oxygen microbubbles alone, with comparable skin
temperatures following application of test or control solution.
[0057] FIG. 6 Shows percent increases from baseline subcutaneous
pO.sub.2 in human subjects during control and oxygenation periods
during immersion of tissue in a whirlpool bath.
[0058] FIG. 7 Shows subcutaneous pO.sub.2 increase over time in
subject HY01 during immersion of leg in a whirlpool bath.
[0059] FIG. 8 Shows subcutaneous pO.sub.2 increase over time in a
subject HY07 during immersion of leg in a whirlpool bath.
4.0 DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0060] There is a need for improved treatments for skin disorders
such as gangrene, skin ulcers, bedsores, burns, and other serious
dermatological problems. The present invention utilizes the
application of a highly oxygenated product in the treatment of
several skin disorders. The disclosed highly oxygenated products
will be useful in treatment of skin diseases related to
degeneration of skin tissue due to oxygen deprivation, such as
ulcers, burns and skin wounds.
4.1 OXYGEN RELEASE TO CELLS
[0061] As shown in FIG. 1, oxygen is transported from the air into
the body. Air, which contains approximately 20% oxygen, passes upon
inhalation into the bronchial tubes and ultimately into the alveoli
of the lungs. In the alveoli, oxygen diffuses across very thin
capillary walls to enter the bloodstream, where it combines with
hemoglobin in the red blood cells to form oxyhemoglobin. As the
blood circulates through the body, oxygen is released from the
oxyhemoglobin and diffuses into the tissues and cells of the body,
including the skin.
[0062] Gases are usually measured in terms of pressure. Air is a
mixed gas and is measured in terms of absolute and partial
pressure. For example, at sea level air has an atmospheric pressure
of 760 mm of mercury (Hg), meaning that it will support a column of
mercury 760 mm high in a tube 1mm in diameter. Oxygen makes up 20%
of the gases in air; thus the partial pressure of oxygen (pO.sub.2)
is 20% of 760, or 152 mm Hg. At higher altitudes, the pO.sub.2 of
air is decreased. In the lungs, the partial pressure of oxygen is
100 mm Hg.
[0063] The diffusion of oxygen into cells and tissues depends on
the partial pressure of oxygen, the solubility of oxygen in the
body fluids and on the health of the tissue. Oxygen does not
penetrate the skin at atmospheric pressure, but only interacts with
the outer surface. Thus under normal conditions, the skin is
nourished not from oxygen in the air, but from O.sub.2 that
diffuses from beneath into the deep, living layers of the epidermis
and the underlying dermis from capillaries in the dermis (FIG. 2A).
Compromise to the blood supply of the skin through damage or
disease thus severely affects the ability of the damaged skin to
obtain an adequate oxygen supply.
[0064] Hyperbaric oxygen therapy is a systemic treatment to
increase tissue oxygenation involving administration of oxygen at
pressures higher than atmospheric pressure. This requires the use
of a special chamber to contain the high pressure (usually between
2 and 3 times atmospheric) which is needed to force extra oxygen to
dissolve in the plasma, which in turn forces it into the tissues.
To date, the majority of skin conditions resulting from lack of
oxygen are treated with systemic hyperbaric methods and
nonoxygenated topical applications. For example, the hyperbaric
oxygen chamber has been established as the primary therapy in the
treatment of medical disorders such as Clostridial Myonecrosis (Gas
Gangrene). On average, treatments usually last from 1 to 2 hours at
full pressure, which may be problematic because extended exposure
to hyperbaric treatment at these pressures produces high risks of
toxicity.
[0065] Hyperbaric oxygen therapy is also used to treat bedsores.
Skin has a rich blood supply that delivers oxygen to all its
layers. If that blood supply is cut off for more than two or three
hours, the skin begins to die, beginning at its outer layer, the
epidermis. A common cause of reduced blood flow to the skin is
pressure. Normal movement shifts pressure and enables the
continuous movement of the blood supply. Once a person is limited
in movement or bedridden they are at a high risk for developing
bedsores. Bedsores can further develop into decubitus ulcers. These
ulcers can open skin to the bone, causing a great deal of pain and
can result in a life-threatening situation.
[0066] In some cases, "topical hyperbaric" treatment for bedsores,
involving exposure of an isolated portion of the body to oxygen
gas, is claimed to be effective during the early stages of
infection There is concern with this method that there is lack of
penetration of the topically applied oxygen, largely due to the
difference in the pressure under the surface of skin and the
atmosphere (FDA Advisory Meeting, Nov. 17, 1998). Also oxygen
delivery topically causes a burning effect on the surface of a skin
after continuous application to skin.
[0067] In the present invention, a method of tissue oxygenation
using superoxygenating compounds has been developed to treat
dermatological problems by inducing more rapid healing. The tissue
is provided with oxygen by a method utilizing topical application
of highly oxygenated water or other fluid incorporating microscopic
oxygen bubbles. When applied for example to skin, the oxygen is
transported inward from the surface through the deeper layers of
the skin (FIG. 2B), thereby providing oxygen to the cells of the
epidermis and underlying dermis. The highly oxygenated solutions
will increase the level of oxygen in the subcutaneous and
subepithelial tissues and promote healing by providing oxygen to
oxygen-depleted cells.
5.0 EXAMPLES
[0068] The following examples are included to demonstrate preferred
embodiments of the invention. It should be appreciated by those of
skill in the art that the techniques disclosed in the examples
which follow represent techniques discovered by the inventors to
function well in the practice of the invention, and thus can be
considered to constitute preferred modes for its practice. However,
those of skill in the art should, in light of the present
disclosure, appreciate that many changes can be made in the
specific embodiments which are disclosed and still obtain a like or
similar result without departing from the spirit and scope of the
invention.
MATERIALS AND METHODS
[0069] Superoxygenated solutions were prepared according to
processes for enriching a liquid with oxygen by introducing the
liquid into an oxygen enriching vessel similar to the disclosure of
U.S. Pat. No. 5,006,352, hereby incorporated by reference. Briefly,
the oxygenation process is carried out in an oxygen enriching
apparatus as disclosed in U.S. Pat. Nos. 5,766,490 and 5,814,222,
herein incorporated by reference in their entirety.
[0070] The process utilized by the inventors introduces a liquid
into a closed space or pressurized vessel, mixes the liquid with
oxygen in a turbulent mixer and recovers an oxygen-enriched liquid
with an oxygen content of at least 40 mg/l oxygen. A
superoxygenated fluid having an oxygen concentration of 180-217 ppm
was prepared using distilled water. This solution contained oxygen
microbubbles with diameters averaging about 1 micron and usually in
the range of 0.6-8 microns, as measured using a flow impedence
device. For measurement of bubble diameters oxygenated water
samples were dispersed by mixing equal amounts of each with Isoton
II in 20 ml cuvettes. Analyses were performed with a 30 .mu.m
aperture tube using Time-mode for 30 seconds. Table 1 summarizes
results showing that the mean size of the oxygen bubbles was in the
range of 1 .mu.m. Attempts to measure particle size using a laser
diffraction instrument were unsuccessful.
1TABLE 1 Particle Size VOLUME MEAN SIZE NUMBER MEAN SIZE SAMPLE
(.mu.m) (.mu.m) 119-155 6.29 1.30 107-123 2.21 1.07 180-216 9.31
1.11
[0071] Distribution of particle size in a typical sample is
represented in FIG. 3. The graph shows particle distribution in
terms of solution volume, indicating that in the sample 90% of the
particles were 1-2 .mu.m in diameter. 5.1 EXAMPLE 1-INCREASE IN
SUBCUTANEOUS OXYGEN IN PORCINE SKIN
[0072] This example demonstrates that a solution containing
superoxygenated microbubbles, applied topically to the skin of a
pig, increases the level of oxygen in the underlying subcutaneous
tissue.
[0073] The skin was cleaned with alcohol, hydrogen peroxide and
then water. Arterial blood gas monitoring devices ("sensors")
capable of simultaneous measurement of partial pressure of carbon
dioxide (pCO.sub.2), temperature and pH were inserted 1-4 mm
beneath the skin surface, on the left and right sides of the body.
Containers for test solutions, such as flexible bags with tubes at
one end, were affixed with adhesive to the skin surrounding the
sensor. The containers provided a means of immersing the skin under
a column of test or control solution during the test. Prior to
filling the containers, controls established that the choice of
adhesive (Fixodent.RTM. or Stromahesive paste) had no effect on the
baseline pO.sub.2 reading.
[0074] The sensors were allowed to equilibrate for 30 minutes and
both were stable before the interventions were begun. Control and
test solutions were heated to 34.degree. C. and equal volumes were
added to the container to ensure equal pressure on the skin site
during measurement. Control solution was distilled water (approx.
7-9 ppm O.sub.2) and the test solution was superoxygenated water
having an O.sub.2 content of 180-217 ppm.
[0075] As shown in FIG. 4, at the start of testing, baseline
pO.sub.2 was 55 mm Hg in the sensor positioned at the test site on
the left side. The control solution was placed in the container for
6 min, during which interval no increase in pO.sub.2 was seen (FIG.
4). The control solution was removed and test solution was placed
in the container at t1 and again four minutes later (second dotted
line). Addition of the test solution resulted in an increase in
pO.sub.2 from 54 to 117 mm Hg. This tissue level was 23% higher
than the arterial pO.sub.2 value of 95 mm Hg. (FIG. 4). As soon as
the test solution was removed by suction, the pO.sub.2 returned to
baseline.
[0076] The cycle was then repeated. Control solution was placed in
the container thirty minutes later (12:30) and more was added to
keep the skin surface covered. No increase in pO.sub.2 was
observed. Subsequently, the control solution was removed and
replaced with several additions of test solution (dotted lines).
With additions of test solution, there were peaks in pO.sub.2
levels (FIG. 4).
[0077] Sensor response is known to be affected by temperature. It
was important to determine the relationship between the pO.sub.2
increases and the skin temperature at the test site. As seen in
FIG. 5, both the control and test solutions altered the skin
temperature by 1-2.degree. C. Because the pO.sub.2 increased only
with the superoxygenated test solution, it was concluded that the
increases in pO.sub.2 were not due to changes in temperature but
were actually due to the application of the test solution to the
surface of the skin.
[0078] A second test using the sensor implanted on the right side
of the animal revealed the importance of the placement of the
electrode. Differences were not observed between the pO.sub.2
levels recorded with control and test solutions. However, the
baseline pO.sub.2 at the site was 75 mm Hg, much closer to the
blood pO.sub.2 level of 90 mm Hg, (as compared with 55 mm Hg on the
left side site). This may have been due to the sensor being in
close proximity to a capillary. Gas exchange from the blood may
have caused the differential between the flowing blood and the test
solution to be too small to observe. Alternatively, the sensor may
have been placed too deep to detect diffusion of O.sub.2 through
the skin.
5.2 EXAMPLE 2:INCREASE IN SUBCUTANEOUS OXYGENATION IN HUMAN
SUBJECTS
[0079] Results from procedures with human subjects demonstrated
that oxygen in superoxygenated solutions prepared as described can
be delivered to subcutaneous tissue through healthy human skin to
increase subcutaneous pO.sub.2 above baseline levels.
[0080] After receiving informed consent from ten human subjects,
baseline blood pressure and heart rate were measured. A pulse
oximeter probe was placed on the subject's finger for continuous
monitoring of heart rate and oxygen saturation throughout the
study. The skin over the outside of the left calf was disinfected
with betadine and the betadine cleaned from the surface of the
skin. A catheter (22 Ga, 1-3/8" catheter, Product No. 04122, Arrow)
was surgically inserted in under the surface of the skin and then
out, so the tip of the needle and catheter were exposed and almost
the entire length of the catheter was in the subcutaneous space.
The catheter was placed as close to the surface of the skin as
possible without driving the needle through the skin prematurely,
in order to place the catheter in the dermis or at the border of
the dermis and subcutaneous tissue.
[0081] After the catheter was placed, the needle was removed and
the tip of the sensor was lined up with the tip of the catheter.
The sensor was advanced through the catheter using the sensor
advancement mechanism until it was visible from the other end of
the catheter. The catheter was removed and the sensor was drawn
back until the tip of the sensor just disappeared beneath the skin.
The sensing element was 2.5 cm long and was completely contained
beneath the skin. The holes made by the catheter were covered by a
water resistant dressing (Duoderm.RTM. thin, Product number NDC
0003-1879-55, ConvaTec) and the sensor housing was taped in place
to keep the weight of the housing and cable from pulling the sensor
out.
[0082] The skin around the sensor was prepped with a barrier wipe
(Allkare.RTM., ConvaTec). Stoma paste (Stomahesive, Product number
NDC 0003-1839-10 ConvaTec) was placed on the skin where the
flexible bag (ActiveLife.RTM., Product number NDC 0003-0254-33,
ConvaTech), with a 2.5" hole, was to be placed. The bag was then
placed on the applied paste. Any gaps between the bag and the skin,
particularly around the sensor housing, were filled with stoma
paste. The bag was also sealed to the skin with Hytape around the
sensor housing.
[0083] Tests were performed in two phases, the first phase
involving testing of responses to control and oxygenated solutions
applied over the sensor sites by means of attached bags, as in
Example 1. The second phase, carried out after the first on the
same patients, involved removal of the bag while maintaining the
sensor in place, to enable subsequent testing of responses when the
legs of the subjects were immersed in test solutions in a whirlpool
bath. The whirlpool bath was a standard stainless steel bath
approximately 30" long.times.18" wide.times.30" high of the sort
typically used for physical therapy and in other clinical
settings.
[0084] In phase one, two different concentrations of oxygenated
water and a control solution in the bag. The oxygenated water for
this test was prepared as previously described. The sensor was
allowed to equilibrate for 30 minutes after insertion. The sensor
simultaneously measured and recorded temperature, partial pressure
of oxygen (pO.sub.2), carbon dioxide (pCO.sub.2) and pH. Data were
collected every 10 seconds on a laptop computer throughout the
entire study. Individual bottles containing these solutions were
heated to 32.degree. C. (except for a few subjects; see Table 2).
The order of these solutions was randomized. 500 ml of the selected
solution was placed in the flexible bag, which was then closed with
the clip. The solution remained in contact with the skin for 15
minutes. A 15 minute stabilization period was maintained between
each solution. Not all subjects received 3 solutions (see Table 2).
At the completion of this phase the bag was cut from the adhesive
frame to expose the skin-covered sensor to air and eventually to
water in the whirlpool.
[0085] For the second (whirlpool) phase, the procedure for
producing the oxygenated solutions was modified as follows. Oxygen
is known to dissipate rapidly from solutions in open vessels. In
order to continuously maintain elevated oxygen levels in the
solutions as the solution circulated in the open bath, the outflow
from the bath was connected to the inlet of the oxygenation
machine, which allowed for recirculation at a rate of 35 gal/min,
and return of all of the water to the bath every 2 minutes. Both
control and oxygenated solutions were subjected to pressures of 90
psi within the machine, and continuously circulated throughout the
tests. Oxygenation of the circulating water was achieved rapidly
after activating the oxygen input in the machine, and the level of
O.sub.2 was monitored throughout the test by a dissolved oxygen
meter in the bath. The presence of the oxygen in the water was also
detected visibly by the change in its appearance to a milky white
solution.
[0086] The tape covering the sensor was removed and the bag
adhesive pulled back part way. The sensor was withdrawn from the
skin using the sensor retraction mechanism. The subject's blood
pressure and heart rate were measured at the end of the study. In
three of the subjects the thickness of the dermis and depth of the
sensors were measured using a 20 MHz ultrasound system from GWB
International.
[0087] At the beginning of this period the sensors had been in the
tissue at least 1 hour. When the leg was inserted into the heated
whirlpool the temperature quickly (within<1 min) rose to the
level of the bath. The baseline readings for temperature, pO.sub.2,
pH and pCO.sub.2 were recorded just at the time the temperature
stabilized to the bath level. Control readings and subcutaneous
oxygenation readings were taken at the end of the period for each
subject. Statistical analysis was performed on the data collected
during the whirlpool phase. Changes in temperature and subcutaneous
pO.sub.2 between baseline, control and oxygenation periods were
compared with a repeated-measures Anova test, followed by a Tukey
HSD test to elucidate differences between the time periods.
[0088] Five male and five female subjects were tested in this
study. Table 2 details the specific characteristics of each of the
subjects and the protocol. All subjects would be considered
overweight (BMI 25). Subjects received slightly different treatment
before the whirlpool study. However every subject had at least 1
hour sensor stabilization time before the whirlpool study began and
every subject spent approximately 30 minutes in the oxygenated
water. All statistical analysis was limited to the time period in
the whirlpool.
2TABLE 2 Subject characteristics and specific protocols whirlpool
whirlpool test soln 1 test soln 2 test soln 3 total time before
cntrl (m) O2 (m) Temp Subject Gender Age BMI (15 m) (15 m) (15 m)
whirlpool (m) .about.4 ppm .about.55 ppm (C.) HY01 F 41 35.1 4 ppm
4 ppm 112 ppm 109 11 24 32 HY02 F 42 31.1 120 ppm 115 ppm 4 ppm 105
16 34 32 HY03 M 43 26.5 101 ppm 4 ppm 90 17 30 32 HY04 M 46 25.8
131 ppm 118 ppm 4 ppm 121 16 33 32 HY05 F 41 34.0 116 ppm 4 ppm 120
ppm 127 15 36 32 HY06 M 53 27.0 134 ppm 4 ppm 92 30 30 32 HY07 F 54
30.1 111 ppm 4 ppm 92 30 33 34 HY08 M 41 31.9 131 ppm 60 30 34 35
HY09 F 44 33.6 150 ppm 61 30 26 37 HY10 M 40 33.0 130 ppm 60 30 33
34
[0089] Table 3 details a qualitative assessment of the sensor
depth, with quantitative measurements for the 3 subjects with
studied with ultrasound. Based on the ultrasound measurements, if
the sensor could be felt as a bulge through the skin, it is likely
that the sensor was at the interface between the dermis and
underlying subcutaneous tissue. In one subject (HY03), the sensor
came out because it failed to be locked in place. This subject had
the sensor re-inserted in the same region of tissue. Another
subject (HY09) had bleeding when the sensor was inserted and a blue
line of blood was observed under the skin, along the sensor,
suggesting that this sensor may have been sitting in blood. In a
third subject (HY10) there was bleeding when the sensor was
removed, suggesting that there may have been blood in the channel
for this subject as well.
3TABLE 3 Sensor depth assessment and notes on specific subjects
Subject Sensor Depth Notes HY01 could see bulge below skin first
test solution 39.degree. C. HY02 Could not see below skin sensor
deep HY03 could see bulge below skin reinserted sensor HY04 could
feel sensor under skin HY05 Could not feel, 2-3 mm deep Ultrasound
before whirlpool HY06 could feel sensor under Ultrasound before and
after skin, .about.1.5 mm deep sensor placed HY07 could feel sensor
under Ultrasound after sensor placed skin, .about.1.5 mm deep HY08
could feel sensor under skin HY09 could feel sensor under skin
bleeding when put in catheter, blue line along sensor HY10 could
feel sensor under skin some bleeding observed on removal
[0090] For the whirlpool phase of the testing, the bath was heated
to 32.degree. C. (except for a few subjects, see Table 4). For the
first 5 subjects, the leg was immersed in the bath in control
solution (distilled water at 4 ppm O.sub.2) for 15 minutes. For the
last 5 subjects, the control phase lasted 30 minutes. After the
control period, the oxygenation machine was turned on to oxygenate
the water. Full oxygenation (.about.55 ppm) was reached in 3-4
minutes and the leg was immersed for 30 minutes in oxygenated
water. The subject's leg was then removed from the bath and
followed for 15 minutes. Plots of temperature and subcutaneous
pO.sub.2 throughout the entire protocol for selected subjects are
shown in FIG. 6 and FIG. 7.
4TABLE 4 Temperature and subcutaneous pO.sub.2, pH, and pCO.sub.2
for the whirlpool protocol PO.sub.2 PO.sub.2 PO.sub.2 temp temp
temp PCO.sub.2 PCO.sub.2 PCO.sub.2 pH pH pH Subject start cntrl wO2
start cntrl wO2 start cntrl wO2 start cntrl wO2 HY01 38 37 85 33
33.6 34.6 33.3 34.9 38.3 7.44 7.41 7.38 HY02 22 18 31 31.4 33.1
35.7 32.1 34.3 38.7 7.47 7.46 7.42 HY03 28 20 18 32.7 33 35.6 29.6
30.5 35.7 7.46 7.45 7.40 HY04 21 20 27 32 32.1 33.4 41.5 42.7 46.5
7.41 7.40 7.38 HY05 11 10 19 31.3 32.2 33.1 36.1 36.1 39.0 7.45
7.44 7.41 HY06 40 40 49 32.3 32.5 34.1 34.3 34.2 36.2 7.46 7.45
7.43 HY07 22 29 70 32.7 34.1 34.3 40.3 40.0 40.4 7.43 7.42 7.39
HY08 28 24 32 35.1 35.2 35.4 41.4 44.1 46.8 7.40 7.37 7.35 HY09 53
54 60 37 36.7 36.5 37.5 39.7 41.7 7.41 7.38 7.30 HY10 42 42 47 34.1
34.2 34.4 33.8 34.4 35.7 7.46 7.45 7 Mean 31 29 44 33.2 33.7 34.7
36.0 37.1 39.9 7.44 7.42 7.39 Std dev 13 14 22 1.8 1.4 1.1 4.1 4.3
4.1 0.03 0.03 0.04
[0091] A summary of the whirlpool data for all subjects is shown in
Table 4. The mean pO.sub.2 for the 10 subjects started at 31 +/-13
mm Hg, but was not significantly different at the end of the
control period (29 +/-14 mm Hg). After immersion in the oxygenated
water, the subcutaneous pO.sub.2 increased significantly to 44
+/-22 mm Hg (p.ltoreq.0.026 compared to baseline and p.ltoreq.0.016
compared to the end of control). The percent increase (or decrease)
in subcutaneous pO.sub.2 during the control and oxygenation periods
for each of the subjects is shown graphically in FIG. 8.
[0092] From FIG. 8 it can be seen that the percent increase in
pO.sub.2 varied considerably among the subjects, with 6 of the 10
showing increases in subcutaneous pO.sub.2 of at least 30%.
Significantly greater increases (141%, 130%, 90%, 70%) were
observed for subjects HY07, HY01, HY05 and HY.sub.02, respectively.
From Table 3 it can be seen that there is an increase in tissue
temperature during both the control and oxygenation phases of the
study. The temperature at the end of the oxygenation phase is
significantly different from baseline (p.ltoreq.0.0006) and from
the end of the control period (p.ltoreq.0.015). These temperature
changes are accompanied by an increase in tissue pCO.sub.2 and a
decrease in tissue pH. Table 5 shows the average percent increase
in baseline values for each of the parameters measured. In this
analysis pH was converted to hydrogen ion concentration
[H.sup.+].
5TABLE 5 Average percent increase from baseline at the end of the
control and oxygen periods Average percent increase from baseline
Control With O2 Temperature 2 5 P.sub.scO.sub.2 -4 44
P.sub.scCO.sub.2 3 11 [H+] 4 12
[0093] The data show that there is a significant increase in
subcutaneous oxygen tension when the subject's leg is immersed in
the oxygenated water, when compared to either baseline or control
values in which the whirlpool contained regularly oxygenated
(.about.4 ppm) water. Coincident with the subcutaneous pO.sub.2
increase is an increase in temperature. The increase in temperature
does not appear to affect the sensor response (which corrects for
changes in temperature) but does have a number of physical and
physiologic effects. As temperature increases, the solubility of
oxygen in the blood decreases, increasing its release to the
tissue. Also, temperature increases result in enhanced dissociation
of oxygen from oxyhemoglobin. Lastly, increases in temperature
result in vasodilation, which should bring more oxygen to the
tissue. Nevertheless, for subjects HY01, HY05, HY07, HY08 and HY10,
the increases in pO.sub.2 seemed to be due to sources beyond those
caused by a temperature rise, where for all subjects except HY10
the temperature rise was less than 1.degree. C. It is possible
however that the observed pO.sub.2 increases may have been due to
temperature in subjects HY02, HY04 and HY06 where the squared
correlation coefficient (R.sup.2) between pO.sub.2 and temperature
is above 0.8.degree. C.
[0094] The levels of pCO.sub.2 and [H.sup.+] increase during the
period when the circulating water is being oxygenated. Both
increase the same amount, which is not surprising given their
dependence through the bicarbonate equilibrium. The source for
these changes was not determined.
[0095] One subject (HY03) showed a decrease in pO.sub.2 as a result
of oxygenation. In this subject the sensor had to be reintroduced a
second time. Injury to the tissue may have resulted in an impaired
response to oxygen. A second subject (HY09) had obvious bleeding
when the sensor was inserted and the sensor may have been insulated
from the interstitial fluid by blood, dampening the response to the
added oxygen. Some, though less, blood was observed when
withdrawing the sensor from subject HY10 and may explain a small
response from this subject as well. When the sensor is inserted in
tissue, ample time must be allowed for temporary tissue injury to
subside. Initially 30 minutes was believed to be acceptable, but
continued decline after that period indicated that all injury was
not resolved. Taking baseline readings at the beginning of the
whirlpool period allowed at least 60 min stabilization for each
subject. This time is consistent with studies conducted in Sweden
using the Paratrend.RTM. sensor directly in subcutaneous tissue of
swine (Mellstrom et al., 1999). The baseline values in those
studies were not that different from those measured in this study:
pO.sub.2: 58 +/-16; pCO.sub.2: 42 +/-5, and pH 7.46 +/-0.06. In a
study of surgical patients where a polarographic oxygen electrode
was used, baseline subcutaneous pO.sub.2 was found to be 43 +/-10
(Hopf et al., 1997). These reported values may be slightly
different than values in these experiments because those sensors
were probably placed deeper than the present ones, which were
likely near the edge of the dermis.
[0096] Results showed that in at least half of the subjects there
was a significant increase in tissue pO.sub.2 related to the
introduction of oxygen microbubbles in the whirlpool bath. The
whirlpool was more effective than still oxygenated water (phase 1
of the test) in producing an increase in subcutaneous pO.sub.2,
despite the higher concentration of oxygen in the water used in the
flexible bags (101-150 ppm O.sub.2 vs. 55 ppm in the whirlpool). In
the two subjects where there was a very good response in the
whirlpool (HY01 and HY07) there was also a measurable response to
oxygenated water in the bags. These were the only two subjects
where there was a response during the bag portion of the study .
These results indicate that individual subjects may differ in the
rate of diffusion of oxygen through their skin to the sensor.
[0097] Sensor depth was controlled between 1 and 3 mm beneath the
surface of the skin. However in the three subjects examined with
the ultrasound, the structure of the skin and the thickness of the
epidermis were quite variable. If oxygen is diffusion limited, it
may only get to a certain depth. Different subjects may differ in
their ability to hydrate or in the permeability of their skin to
gas. Nevertheless, the results of the study showed that the high
partial pressure of oxygen in the oxygenated water permitted a high
enough concentration of oxygen outside the skin to facilitate
diffusion of oxygen through the skin of the majority of the healthy
subjects. Furthermore, permeability of the skin would not be a
problem for the treatment of open wounds.
5.3 Example 3: Application of Method of Tissue Superoxygenation to
Wound Healing
[0098] Preliminary studies will be conducted in diabetic patients
and compared to those performed in animal and normal human testing
to determine the effect of superoxygenated microbubbles on the rate
of healing when administered to the non-healing wounds of diabetic
patients. Patients will be maintained under tightly-controlled
environmental conditions. Additionally, the wound area will be
analyzed and anaerobic bacteria identified according to studies
performed at the Institute of Molecular Biology and Medicine at
University of Scranton. According to that study, approximately
10-20% of diabetic foot wounds fail initial antibiotic treatment.
It is generally believed that several bacterial species may be
present in these types of wounds. Because some of these organisms
cannot be easily cultured, proper identification is problematic and
thus, appropriate treatment modalities cannot be applied. The
report examined the bacterial flora present in a chronic diabetic
foot wound that failed antibiotic treatment. A tissue sample was
collected from the base of the wound and used for standard
microbiological culturing. DNA from the sample was used to amplify
bacterial 16 S rDNA gene sequences and prepare a library, the
clones of which were sequenced. The culture-based method identified
a single anaerobic species, Bacteroides fragilis, whereas the
method employing rDNA sequencing identified B. fragilis as a
dominant organism and Pseudomonas (Janthinobacterium) mephitica as
a minor component. The results indicated that the rDNA sequencing
approach can be an important tool in the identification of bacteria
from wound (Redkar et al., 2000).
[0099] Experiments will be conducted in controlled randomized
fashion by administering the compositions to the wound area in
varying concentrations and forms with subsequent analysis of the
bacteria present in untreated wounds and those treated with
superoxygenated water.
5.4 Example 4: Tissue Superoxygenation in Treatment of Leg
Ulcers
[0100] A clinical study was undertaken to investigate and compare
specifically the aerobic and anaerobic microbiology of infected and
noninfected leg ulcers. Leg ulcers, defined as infected on the
basis of clinical signs, were swab sampled and tested for aerobic
and anaerobic microorganisms using stringent isolation and
identification techniques (Bowler et al., 1999).
[0101] In this study, 220 isolates were cultured from 44 infected
leg ulcers, and 110 isolates were from 30 non-infected leg ulcers.
Statistical analysis indicated a significantly greater mean number
of anaerobic bacteria per infected ulcer (particularly
Peptostreptococcus spp. and Prevotella spp.) in comparison with the
noninfected ulcer group (2.5 vs. 1.3, respectively) (P<0.05).
Also, anaerobes represented 49% of the total microbial composition
in infected leg ulcers compared with 36% in non-infected leg ulcers
(Bowler et al., 1999).
[0102] Based on the results of these studies, superoxygenated
microbubble compositions will be used to test the effect of the
oxygenation treatment on the distribution of aerobic and anaerobic
microflora which exist in leg ulcers. An indication of the
effectiveness of the composition in combating leg ulcers and other
wound infections will be determined by noting the relative changes
in distribution of the anaerobes and aerobes.
5.5 Example 5: Superoxygenated Ice
[0103] The following example demonstrates the ability of highly
oxygenated ice to hold high levels of oxygen and release oxygen at
high levels. Results indicated that ice can be made with highly
oxygenated water and that both the ice and melt fluid contain high
concentrations of oxygen compared with tap water and ice as
controls.
[0104] Two bottles of super-oxygenated (SO) fluid were stored at
-15.degree. C. A third bottle was chilled at 8.degree. C. Control
samples were ice from tap water and tap water chilled to 8.degree.
C. The superoxygenated fluids were stored for approximately 6
months in tightly capped bottles. Oxygen levels ranged from 107 to
123 ppm at the time of storage. The bottles were removed from
storage and oxygen levels measured with a modified high range
Oxygard Handy Mk II meter with a standard unit of measurement of
parts per million. The meter measured the oxygen at the surface of
the ice where the ice initially melted ((Ice reading). The melt
water was also measured (melt reading). The same measurements were
made for the control tap water and tap water ice. Samples at
8.degree. C. were poured into an open container and oxygen levels
measured directly. Results are shown in Table 6.
6TABLE 6 Oxygen Levels in superoxygenated and tap water ice Sample
Frozen melt Stored at 0.degree. C. Superoxygenated water
-15.degree. C. 82 ppm 56 ppm -- Superoxygenated water 0.degree. C.
-- -- 103 ppm Tap water -15.degree. C. 7 ppm 7 ppm -- Tap water
0.degree. C. -- -- 4 ppm
6.0 References
[0105] The following literature citations as well as those cited
are incorporated in pertinent part by reference herein for the
reasons cited in the above text:
[0106] Bowler, Philip G.; Davies, Barry J., The microbiology of
infected and noninfected leg ulcers, International Journal of
Dermatology, 38(8): 573-578, 2000.
[0107] Elden, Harry R.; Kalli, Ted, Hydrogen Peroxide Emulsions,
DCI Magazine, 157(vc): 38, 40, 42, 44, 47, 1995.
[0108] FDA Medical Devices Advisory Committee Meeting of: General
and Plastic Surgery Devices Panel Closed Session, Nov. 17,
1998.
[0109] Hopf H W, Hunt T K, West J M, et al. Wound tissue oxygen
tension predicts the risk of wound infection in surgical patients.
Physiology of wound healing. Arch Surg 132:997-1004, 1997.
[0110] Hunt T, Rabkin J, Jensen J A, et al. Tissue oximetry: an
interim report. World J Surg 11:126-132, 1987.
[0111] Jonsson K, Jensen J A, Goodson W H, et al. Tissue
oxygenation, anemia, and perfusion in relation to wound healing in
surgical patients. Ann Surg 214:605-613, 1991.
[0112] Ladin, U.S. Pat. No.5,792,090, 1998.
[0113] Loori, U.S. Pat. No. 5,154,697, 1992.
[0114] Loori, U.S. Pat. No. 5,801,291, 1989.
[0115] Mellstrom A, Hartmann M, Jedlinska B, et al. Effect of
hyperoxia and hypoxia on subcutaneous tissue gases and pH. Euro
Surg Res 31:333-339,1999.
[0116] Moschella and Hurley. Chapter 4: Permeability in
Dermatology. W. B. Saunders; 1992
[0117] Quay, U.S. Pat. No. 5,573,751, 1996.
[0118] Redkar R; Kalns J; Butler W: Krock L; McCleskey F; Salmen A;
Piepmeier E Jr; Del Vecchio V, Identification of bacteria from a
non-healing diabetic foot wound by 16 S rDNA sequencing, Molecular
and Cellular Probes, 14(3): 163-169, 2000.
[0119] Scherson et al., U.S. Pat. No. 5,855,570, 1999.
[0120] Spears, et al., U.S. Pat. No. 6,248,087
[0121] Taylor et al., U.S. Pat. No. 5,766,490, 1998.
[0122] Tegner E and A. Bjomberg, Hydrogen Peroxide Cream for the
Prevention of White Pressure Areas in UVA Sunbeds, Acta Derm,
Venerol. (Stockh), 70:75, 1990.
[0123] Trammell, U.S. Pat. No. 5,029,589, 1991.
[0124] Van Liew et al., U.S. Pat. No. 5,869,538, 1999.
[0125] Whitney J. D., Physiologic Effects of Tissue Oxygenation on
Wound Healing, Heart and Lung 18: 466-474, 1989.
[0126] Zelenak et al., U.S. Pat. No. 5,814,222, 1998.
[0127] Zelenak nee Zoltai et al., U.S. Pat. No. 5,006,352,
1991.
[0128] All of the methods and compositions disclosed and claimed
herein can be made and executed without undue experimentation in
light of the present disclosure. While the compositions and methods
of this invention have been described in terms of preferred
embodiments, it will be apparent to those of skill in the art that
variations may be applied to the methods and compositions, in the
steps or in the sequence of steps of the method described herein
and in the modification of the apparatus connected with the methods
and compositions without departing from the concept, spirit and
scope of the invention. More specifically, it will be apparent that
certain agents which are both chemically and physiologically
related may be added to, combined with or substituted for the
agents described herein while the same or similar results would be
achieved. All such similar substitutes and modifications apparent
to those skilled in the art are deemed to be within the spirit,
scope and concept of the invention as defined by the appended
claims. Accordingly, the exclusive rights sought to be patented are
as described in the claims below.
* * * * *