U.S. patent application number 15/010549 was filed with the patent office on 2016-05-26 for method and device for collecting and preserving cells for analysis.
The applicant listed for this patent is Streck, Inc.. Invention is credited to Wayne L. Ryan.
Application Number | 20160143268 15/010549 |
Document ID | / |
Family ID | 32069961 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160143268 |
Kind Code |
A1 |
Ryan; Wayne L. |
May 26, 2016 |
METHOD AND DEVICE FOR COLLECTING AND PRESERVING CELLS FOR
ANALYSIS
Abstract
The claimed subject matter comprises a device to collect and
preserve cells comprising of: (1) a collection container comprised
of a tube having an open end and a closed end, a closure in the
open end of the tube, a vacuum drawn to a predetermined level
inside the container; and (2) compounds including an anticoagulant
agent and a fixative agent, wherein the compounds are in a
sufficient amount to preserve said cells" original morphology and
antigenic sites without significant dilution of said cells, and
thereby allowing said cells to be directly analyzed by a flow
cytometer without further treatment. The claimed subject matter
further comprises of a method of making a collection device for
cells comprising of: (1) providing a tube having an open end and a
closed end; (2) preloading compounds including: an anticoagulant
agent, and a fixative agent into the tube, wherein the compounds
are in a sufficient amount to preserve the cells" original
morphology and antigenic sites without significant dilution of the
cells, and thereby allowing the cells to be directly analyzed by a
flow cytometer without further treatment; (3) inserting a closure
into the open end of the tube; and (4) drawing a vacuum inside the
tube to a predetermined level to form the collection device.
Inventors: |
Ryan; Wayne L.; (Omaha,
NE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Streck, Inc. |
LaVista |
NE |
US |
|
|
Family ID: |
32069961 |
Appl. No.: |
15/010549 |
Filed: |
January 29, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12850269 |
Aug 4, 2010 |
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15010549 |
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10605669 |
Oct 16, 2003 |
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12850269 |
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60418978 |
Oct 16, 2002 |
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Current U.S.
Class: |
435/374 |
Current CPC
Class: |
B01L 1/52 20190801; B01L
2200/16 20130101; B01L 3/5082 20130101; A01N 1/0226 20130101 |
International
Class: |
A01N 1/02 20060101
A01N001/02 |
Claims
1-27. (canceled)
28. A method of inhibiting cellular aggregation in a biologically
active sample comprising mixing an effective amount of diazolidinyl
urea with a sample of viable cells, wherein the effective amount of
diazolidinyl urea is in a concentration that is less than about
2:100 upon mixing with the sample of viable cells.
29. The method of claim 28, further comprising mixing an effective
amount of diazolidinyl urea in combination with a non-chelating
agent based anti-coagulating agent selected from hirudin, heparin,
citric acid, salts of citric acid, oxalic acid, salts of oxalic
acid, acid citrate dextrose, or mixtures thereof may be used, with
the sample.
30. The method of claim 28, further comprising mixing an effective
amount of diazolidinyl urea in combination with acid citrate
dextrose with the biological sample.
31. The method of claim 28, wherein the diazolidinyl urea is mixed
with the sample before a biological sample processing or
testing.
32. The method of claim 28, wherein the diazolidinyl urea is in a
solid or liquid form in a container and wherein the biological
sample is added to the container.
33. The method of claim 28, wherein the biological sample is
selected from the group consisting of whole blood, blood and bone
marrow.
34. The method of claim 28, wherein upon mixing with the effective
amount of diazolidinyl urea the biological sample is suitable for
use in a microchannel for cell capturing.
35. The method of claim 28, wherein the effective amount of
diazolidinyl urea in the biological sample provides for improved
cell capture in a microchannel as compared to that in the absence
of diazolidinyl urea in the biological sample.
36. A method of inhibiting cellular aggregation in a biological
sample comprising mixing an effective amount of diazolidinyl urea
with the sample, wherein cellular aggregation is reduced in the
presence of diazolidinyl urea compared to the absence of
diazolidinyl urea in the sample, wherein the effective amount of
diazolidinyl urea is in a concentration that is less than about
2:100 upon mixing with the biological sample, and wherein upon
mixing with the effective amount of diazolidinyl urea the
biological sample is suitable for use in a microchannel for cell
capturing.
Description
BACKGROUND
[0001] In biological and biochemical analysis, and related arts, it
is often necessary to collect and preserve biological tissues
(i.e., cells and cellular components), for useful periods of time.
The collected and preserved cells are often utilized in a wide
variety of applications, including but not limited to instructional
aids and the diagnosis and treatment of diseases. For example, such
cells are often utilized in histological, cytological,
immunological, and proteinaceous studies and the like.
[0002] Various methods are known in the art for analyzing
histological, cytological, immunological, and proteinaceous
materials. For example, surface marker analysis has developed as a
laboratory tool, which is particularly useful for clinical
diagnosis through the investigation of immunostates,
differentiation of cell types and development stages, and other
cell processes. The expansion of uses for surface marker analysis
has resulted in the use of flow cytometry and antibody probes to
evaluate cellular properties. While other means of assaying for
surface marker analysis exist, flow cytometry provides rapid,
objective and quantitative assessment of surface markers.
Furthermore, even though the microscope is still the conventional
means for examining preserved and stained biological materials,
biological materials may also be examined with a flow cytometer.
The flow cytometer is an important method for examining a plurality
of cells in a brief time.
[0003] Flow cytometry and flow cytometers are generally described
in Keran's text, Flow cytometry in Clinical Diagnosis (1989). Flow
cytometers operate in principle by multiparameter analysis of
heterogeneous cell populations (or cellular components) on a
cell-by-cell basis. Flow cytometry allows biological and physical
properties of cells and cellular components to be determined. In
flow cytometry, cells in suspension are forced single file, via
hydrodynamic focusing, through the path of a laser beam.
Interaction of the cells with the laser beam scatters some of the
light and causes excitation and emission from fluorescent molecules
present on the surface or interior of the cell. A series of lenses
collect the scattered or emitted light and pass it to a
photomultiplier. Each photomultiplier measures a separate
parameter. Parameters measured include: forward light scatter,
which measures relative particle size; side light scatter, which
measures relative granularity or other internal structure; and
fluorescence emission. The optical signals are converted by a
computer to a data display for analysis and interpretation. Cells
collected and preserved using conventional methods and instruments
generally require further dilution and/or treatment before they can
be analyzed by flow cytometry. Thus, it is desirable in the art to
obtain a method and a collection device that allow the cells to be
directly analyzed by flow cytometry without further dilution and/or
treatment. (There is need for a method to collect and transport
human blood specimens for flow cytometric analysis. Current methods
are inadequate in that the samples have to be analyzed soon after
collection.)
[0004] The primary objective of tissue preservation is to provide
as much structural detail of cells and components thereof as
possible. To do this, it is necessary to maintain the cells in
their original unaltered morphology so that maximum cellular detail
may be observed. With the clinical application of immunostaining,
there is also the requirement that antigens are not altered by the
method of preservation. Thus, it is desirable in the art to obtain
a method and a collection device that maintain the cells in their
original unaltered morphology and preserve their antigenic
sites.
[0005] The usual formulations for preservation of cells contain one
or more agents, which react vigorously with the proteins of the
cells to denature and insolubilize the components of the cell.
Typical of this type of agent is picric acid, mercuric ions,
formaldehyde and glutaraldehyde. In addition, some less toxic
compounds can also be utilized which denature and stabilize the
proteins such as acetic and formic acid. Unfortunately, the
toxicity associated with such compounds renders their use less than
satisfactory. For example, a 37% solution of formaldehyde, the most
common of these fixatives, is a noxious gas which is also toxic,
flammable, and carcinogenic. Although efforts are made when this
chemical is used to protect workers and avoid contamination of the
drainage system when disposed, these efforts are usually both
expensive and inconvenient, and fixatives such as formaldehyde
still present a danger to laboratory workers and health care
professionals. Thus, it is highly desirable to develop a method and
a collection device, which can preserve the cells in a low toxicity
and non-flammable environment so that it can be used safely,
effectively and conveniently in histological and other studies.
[0006] For even easier handling, it is also desirable to develop a
method and a collection device that allow transportation (e.g.,
from the collection site to the analysis site) of the cells in
ambient temperature.
SUMMARY
[0007] The claimed subject matter addresses many of the challenges
encountered when using conventional methods and instruments to
collect and preserve cells by providing a method and a collection
device that are capable of maintaining the cells in their original
unaltered morphology; preserving the cell antigenic sites; and
allowing the cells to be transported at ambient temperature, to be
handled in a low toxicity and non-flammable environment, and to be
directly analyzed by flow cytometry without further dilution and/or
treatment. The claimed subject matter more specifically relates to
a method and a device that allow cells (e.g., whole blood,
epithelial cells, spinal fluid, and the like.) to be collected and
preserved for analysis and addresses many of the challenges
encountered when using conventional methods and instruments.
Specifically, the claimed subject matter describes a method and a
collection device that (1) use a less toxic and non-flammable
reagent for fixing and stabilizing cells; (2) allow the cells to
stay in their original unaltered morphology; (3) allow the cell
antigenic sites to be preserved for a useful period of time; (4)
allow the cells to be transported at ambient temperature; and/or
(5) allow the cells to be directly analyzed by flow cytometry
without further dilution and/or treatment.
[0008] The claimed subject matter includes a device to collect and
preserve cells comprising of: (1) a collection container comprised
of a tube having an open end and a closed end, a closure in the
open end of the tube, a vacuum drawn to a predetermined level
inside the container; and (2) compounds including an anticoagulant
agent and a fixative agent selected from the group consisting of:
diazolidinyl urea, imidazolidinyl urea,
dimethoylol-5,5dimethylhydantoin, dimethylol urea,
2-bromo-2.-nitropropane-1,3-diol, oxazolidines, sodium
hydroxymethyl glycinate,
5-hydroxymethoxymethyl-1-laza-3,7-dioxabicyclo [3.3.0]octane,
5-hydroxymethyl-1-laza-3,7dioxabicyclo[3.3.0]octane,
5-hydroxypoly[methyleneoxy]methyl-1-laza-3,7dioxabicyclo[3.3.0]octane,
quaternary adamantine and combinations thereof. The claimed subject
matter may optionally include polyacrylic acid or a suitable acid
having a pH ranging from about one to about seven inside the tube.
The compounds of the device must be in a sufficient amount to
preserve the collected cells' original morphology and antigenic
sites without significant dilution of the cells (i.e., in a volume
that is not clinically significant), and thereby allowing the
cells, stored with the compounds, to be directly analyzed by a flow
cytometer.
[0009] The claimed subject matter also includes a method comprised
of (1) providing a tube with an open end and a closed end, (2)
preloading the tube with compounds including: an anticoagulant
agent, a fixative agent selected from the group consisting of:
diazolidinyl urea, imidazolidinyl urea,
dimethoylol-5,5-dimethylhydantoin, dimethylol urea,
2-bromo-2-nitropropane-1,3-diol, oxazolidines, sodium hydroxymethyl
glycinate,
5-hydroxymethoxymethyl-1-laza-3,7-dioxabicyclo[3.3.0]octane,
5-hydroxymethyl-1-laza-3,7-dioxabicyclo[3.3.0]octane,
5-hydroxypoly[methyleneoxy]methyl-1-laza-3,7dioxabicyclo[3.3.0]octane,
and quaternary adamantine, and optionally a polyacrylic acid or a
suitable acid having a pH ranging from about one to about seven,
wherein the compounds are in a sufficient amount to preserve the
collected cells' original morphology and antigenic sites without
significant dilution of the cells, and thereby allowing the cells,
stored with the compounds, to be directly analyzed by a flow
cytometer; inserting a closure into the open end of the tube; and
drawing a vacuum to a predetermined level inside the tube.
[0010] The method and device of the claimed subject matter may also
optionally include other art-disclosed components conventionally
used in cell collection and analysis such as gauze, glove,
tourniquet, lancet, needle, test strip (e.g., immunoassay), alcohol
swab, tube holder, additional cell collection tubes (with or
without conventional cell analysis additives inside these tubes),
adhesive strip, syringe, glass or plastic strip, packaging means to
store the desired components and the device, and packaging means to
transport at least the collected and preserved cells stored in the
device. The method of the claimed subject matter may also
optionally include additional art disclosed methods and instruments
used for cell analysis such as a flow cytometer, a hematology
analyzer, and other hematology instruments, etc.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 A cross-sectional illustration of an exemplary
embodiment of the collection device of the claimed subject matter;
and
[0012] FIG. 2 A flow diagram illustrating a method for making the
collection device illustrated in the FIG. 1.
DETAILED DESCRIPTION
[0013] The claimed subject matter can be satisfied by embodiments
in many different forms, the drawings and the description herein
describe in detail a preferred embodiment of the claimed subject
matter. It is understood that the present disclosure is to be
considered exemplary of the principles of the claimed subject
matter and is not intended to limit the claimed subject matter to
the embodiment illustrated. The scope of the claimed subject matter
is measured by the appended claims and their equivalents.
[0014] Turning now to the drawings, FIG. 1 shows a cross-sectional
illustration of a device 100 that incorporates a preferred
embodiment of this claimed subject matter and can be used to
collect and preserve biological tissues such as cells and cellular
components for analysis. The device 100 is particularly useful in
the collection of whole blood, but can be use to collect other
types of bodily fluids and/or biological tissues (e.g., epithelial
cells, bone marrow, spinal fluid and the like) including, without
limitation, abnormal tissue samples such as leukemias, cancer
tissue cancer, and the like as long as the tissue samples can be
transformed into a cellular suspension.
[0015] The device 100 includes an evacuated collection container 10
comprised of (1) a tube 12 having an open end 14 and a closed end
16; a closure (e.g., stopper) 18 in the open end of the tube 12,
and a predetermined level of vacuum (not shown) inside the
container 10. It is preferred that the tube 12 is made of a
transparent material such as glass or plastic for better
visibility. It is also preferred that the tube 12 has an interior
surface that is sterile and resists adherence to the cells 20 (not
shown) during collection, storage, and analysis. The closure 18 is
preferably puncturable by a needle and resealable allowing easy
transfer of the cells 20 (e.g., the cells 20 from its host to the
container 10 and from the container 10 to another substrate if
desired). It is also preferred that the closure 18 and the tube 12
together form a seal capable of maintaining a pressure differential
between atmospheric pressure and a pressure less than atmospheric
pressure within the tube 18.
[0016] The size of the container 10 is not narrowly critical and is
dependent upon the cell sample volume that is desired to be
collected and preserved. For example, a typical size for the
container 10 may have an internal volume of between 100 .mu.l to 10
ml. The container 10 can be constructed using art-disclosed methods
and is commercially available (e.g., Vacutainer Plus Plastic Tubes
with Hemogard Closure available from Becton Dickinson and Company
located in Franklin Lakes, New jersey; the evacuated sample
collection tube described in U.S. Pat. No. 5,860,937, which is
incorporated by reference). Of course, it should be understood that
a wide range of changes and modifications can be made to the
preferred embodiment described above for the container 10.
[0017] For preservation (e.g., fixation, stabilization and the
like) of the cells 20, the device 100 further includes compounds 22
including an anticoagulant agent 24, a fixative agent 26 selected
from the group consisting of: diazolidinyl urea, imidazolidinyl
urea, dimethoylol-5,5-dimethylhydantoin, dimethylol urea,
2-bromo-2-nitropropane-1,3-diol, oxaizolidines, sodium
hydroxymethyl glycinate,
5-hydroxymethoxymethyl-1-laza-3,7dioxabicyclo[3.3.0]octane,
5-hydroxymethyl-1-laza-3,7-dioxabicyclo[3.3.0]octane,
5-hydroxypoly[methyleneoxy]methyl-1-laza-3,7-dioxabi
cyclo[3.3.0]octane, and quaternary adamantine, and optionally a
polyacrylic acid 28 or any suitable acid having a pH ranging from
about one to about seven, wherein the compounds are in a sufficient
amount to preserve the collected cells' original morphology and
antigenic sites without significant dilution of the cells 20, and
thereby allowing the cells 20, stored with the compounds 22, to be
directly analyzed by a flow cytometer. It is preferred that the
compounds 22 have been sterilized (e.g., by sterilizing
filtration).
[0018] A suitable amount of any art-disclosed anticoagulant agent
such as ethylene diamine tetra acetic acid (EDT A) and its salts,
ethylene glycol tetra acetic acid (EGTA) and its salts, hirudin,
heparin, citric acid, salts of citric acid, oxalic acid, salts of
oxalic acid, or mixtures thereof may be used. A preferred
anticoagulant agent 24 is K.sub.3EDTA. The suitable amount of the
anticoagulant agent 24 for the claimed subject matter is that
effective to prevent coagulation of the cells 20 (e.g., whole
blood) without causing significant dilution of the cells 20 (i.e.,
not clinically significant), and thereby allowing the cells 20,
stored with the compounds 22, to be directly analyzed by a flow
cytometer). For example, in a preferred embodiment, K.sub.3EDTA is
the anticoagulant agent 24 and its concentration weight/volume is
preferably less than about 0.3 g/ml, more preferably less than
about 0.2 g/ml, and most preferably about less than about 0.15
g/ml.
[0019] The preferred fixative agent 26 is a heterocyclic urea
(e.g., diazolidinyl urea (known as DU), imidazolidinyl urea (known
as IDU) or a mixture thereof). The most preferred fixative agent is
diazolidinyl urea. The suitable amount of the fixative agent 26 for
the claimed subject matter is that effective to fix or stabilize
the cells 20 without causing significant dilution of the cells 20
(i.e., not clinically significant), and thereby allowing the cells
20, stored with the compounds 22, to be directly analyzed by a flow
cytometer. For example, in a preferred embodiment, diazolidinyl
urea is the fixative agent 26 and its concentration weight/volume
is preferably about less than about 1 g/ml, more preferably less
than about 0.75 g/ml, and most preferably less than about 0.5 g/ml
concentration of solution of DU before blood sample is added.
[0020] It is known that the acid 28 may rise signal to noise ratio
during flow cytometry; and therefore, the acid 28 may be optionally
added as one of the compounds 22 in the device 100. The preferred
acid 28 is a polycarboxylic acid, and more preferably a polyacrylic
acid with a molecular weight of 5,000. The suitable amount of the
acid 28 for the claimed subject matter is that effective to rise
signal to noise ratio during flow cytometry but without causing
significant dilution to the cells 20 (i.e., not clinically
significant) so that the cells 20, stored with the compounds 22,
can be directly analyzed by a flow cytometry. For example, in a
preferred embodiment, polyacrylic acid with a molecular weight of
5,000 is included in the container 10.
[0021] Additional compounds may optionally be added as one of the
compounds 22 in the device 100. Such additional and optional
compounds may include: cell permeabilizing agents for substantially
gaining access to intracellular analytes/epitopes and/or for lysing
red blood cells; proteins that substantially protect the cells
during processing and/or substantially reduce non-specific binding
of probes; serum/lipoproteins that substantially protect cells
during processing and/or substantially reduce non-specific binding
of probes; RNAse inhibitors which substantially inhibit digestion
of RNA and/or substantially maintain RNA integrity; nucleic acid
stabilizers which substantially inhibit the degradation of nucleic
acids and nucleic acid containing compounds; amino
acids/polypeptides which substantially enhance binding of
probes/antibodies to epitopes and/or substantially increases the
observable signal; fixatives which substantially preserve cell
integrity especially for permeabilization agents, and may preserve
some epitopes; anticoagulants which substantially decreases
clotting of red blood cells, chelates calcium and/or may help
maintain WBC integrity/viability; protease inhibitors which
substantially decreases degradation of protein epitopes;
antioxidants/reducing agents which substantially prevent hemolysis
of red blood cells and/or substantially prevent oxidation of
peptides, and/or substantially maintain epitopes; nucleic acid dyes
that generally serve to label/identify nucleic acid; carbohydrates
which substantially maintain cellular integrity and/or osmolarity;
and, polyacrylic acids which substantially enhance the binding of
probes and/or antibodies to epitopes; and/or substantially
increases signal. One of skill in the art should be able to
determine the usefulness and quantities of such optional compounds
by routine testing and knowledge of the art. Within multiple
specific embodiments the above additional and optional compounds
may be more specifically include: Cell permeabilizing agents such
as: DMSO (Dimethyl Sulfoxide), Ethylene glycol, Polyethylene
glycol, Glycerin, Cellosolves (ethylene glycol dimethyl ether)
(phenoxyethanol), Triton X 100, Triton X 705 (non-ionic
detergents), 1-methyl-2-pyrrolidinone, Tween 20, Tween 40
(non-ionic), Brij 35 (detergent), Polyoxyethylene ether (Polyox),
Sodium cholate, Ethylene oxide polymers, Monensin, Monactin,
Pentachlorophenol, 2,4 dinitrophenol, saponin, SDS (sodium dodecyl
sulfate); Proteins such as: Biotin, Albumins (egg, bovine),
Gelatin, and similar such compounds as should be known to one of
skill in the art; RNAse inhibitors such as: human placenta derived
RNAse inhibitor, and similar such compounds should be known to one
of skill in the art; Nucleic acid stabilizers such as: Guanidinium
hydrochloride, Polycations such as Polyethylenimine), and similar
such compounds as should be known to one of skill in the art; Amino
acids/polypeptides such as: Glutamic acid, Glycine, Aspartic acid,
and similar such compounds as should be known to one of skill in
the art; Fixatives such as: Aldehydes (formaldehyde and
glutaraldehyde), Alcohols (ethanol, methanol), and similar such
compounds as should be known to one of skill in the art;
Anticoagulants such as: EDTA (Ethylene Diamine Tetra acetic acid.),
and similar such compounds as should be known to one of skill in
the art; ACD (Acid Citrate Dextrose), Heparin, and similar such
compounds as should be known to one of skill in the art; Protease
Inhibitors such as: EDTA, PMSF (phenyl methyl sulfonyl fluoride),
AEBSF (2-Aminoethyl benzene sulfonyl fluoride), and similar such
compounds as should be known to one of skill in the art;
Antioxidants/Reducing agents such as: Trolox, a-tocopherol,
B-mercaptoethanol, and similar such compounds as should be known to
one of skill in the art; Nucleic Acid Dyes such as: DAPI (Diamidino
2-phenylindole), Propidium Iodide, Fluorescein diacetate, and
similar such compounds as should be known to one of skill in the
art; Carbohydrates such as: Sugars (sucrose), cellulose, and
similar such compounds as should be known to one of skill in the
art. It should be appreciated that the above specific listings of
compounds may contain a measure of overlap, which recognizes the
sometimes-overlapping function of certain specific compounds. One
of skill in the art should understand and appreciate this aspect of
the disclosure.
[0022] The claimed subject matter allows the final composition 30
to be transported in ambient temperature. Thereafter, it is
preferred that the final composition 30 be stored at temperature
less than about 40.degree. C. The cells 20 stored in the final
composition 30 have more than about 3 days, preferably more than
about 5 days, more preferably more than about 7 days stability. The
claimed subject matter allows the cells 20 stored in the final
composition 30 to be directly analyzed by a flow cytometer without
further dilution and/or treatment because the compounds 22 can
preserve the cells 20 without significantly diluting the cells 20.
Any significant dilution of the cells 20 is likely to cause error
in flow cytometry measurements (e.g., lowering the lymphocytes'
count). To avoid significant dilution, the compounds 22 (comprising
of the anticoagulant agent 24, the fixative agent 26, and
optionally, the acid 28) are in concentrated forms, preferably in a
ratio with the final composition 30 that is less than about 2:100,
more preferably less than about 1.5:100, and most preferably less
than about 1:100.
[0023] The device 100 may be included in a kit of the claimed
subject matter containing components 32 (not shown) conventionally
used to collect and analyze the cells 30 such as alcohol swab,
gauze, tube holder, tourniquet, glove, other cell collection tube
(with or without conventional cell analysis additives inside such
tube), needle (with hub, part of a syringe assembly including
barrel and plunger, or with wings connected via a hub and tubing to
another needle for delivery to the device 100 or other collection
tubes), lancet, adhesive strip, syringe, test strip (allowing the
cells 20 to flow directly onto a glass or plastic strip containing
reagents for cell analysis), glass or plastic strip containing
reagents for cell analysis (e.g., immunoassay), packaging means
(e.g., plastic bag, compartmentalized plastic enclosure, and the
like) to store the desired components 32 and the device 100, and
packaging means to transport the cells 20 stored in the device 100
after collection. It is preferred that the packaging means and any
other components 32 that may become in physical contact with the
cells 20 be sterilized and the packaging means is constructed to
maintain this sterile environment.
[0024] Unlike the typical histological fixing agents, the fixative
agent 26 of the claimed subject matter has extremely low toxicity.
For example, toxicity studies comparing diazolidinyl urea with
formaldehyde of the prior art show the following:
TABLE-US-00001 Inhalation Toxicity Dermal Toxicity LD50
Formaldehyde 500 mg/kg 270 mg/kg 800 mg/kg Diazolidinyl urea None
2000 mg/kg 2570 mg/kg
[0025] This reduced toxicity makes disposal and handling less of a
problem. In addition, since there is no inhalation toxicity, there
are no badge detection devices required as there are for
formaldehyde.
[0026] Another advantage offered by the fixative agent 26 is the
fact that it is not flammable and therefore does not present a fire
hazard as do many of the prior art fixative agents.
[0027] The mechanism by which the fixative agent 26 provides the
desired tissue and cell membrane stabilization is not known for
certain. It is believed that the fixative agent binds in some
fashion to the cell membrane or tissue. This hypothesis is drawn
because many members of the active agent are known disinfectants,
which kill bacteria by binding to cell structure. This is not a
full explanation of the mechanism responsible for the results of
the claimed subject matter since many other disinfectants such as
KATHON and OMADINE fail to provide tissue and cell stabilizing
effects.
[0028] The ability of the fixative agent 26 to preserve antigenic
sites is also not understood but it is probably due to a difference
in the reaction between proteins and the fixative agent 26 compared
to prior art preservatives such as formaldehyde. Formaldehyde
cross-links with itself and proteins to obscure the antigen. To
determine if this is true, diazolidinyl urea was added to the
protein, albumin. After incubation of the diazolidinyl urea and
protein mixture for 24 hours, disc-gel electrophoresis indicated no
change in the rate of migration of the protein. When this
experiment is conducted with formaldehyde, a large number of
insoluble proteins result and the electrophoretic migration is
altered.
[0029] Referring to FIG. 2, a method of making the device 100 of
the claimed subject matter is comprised of providing the tube 12
having the open end 14 and the closed end 16 (202). It is preferred
that the tube 12 is sterile. The method is further comprised of
preloading (i.e., introducing) the compounds 22 comprising of the
anticoagulant agent 24, the fixative agent 26, and optionally the
acid 28 into the tube 12 using art-disclosed methods (204). The
types and amounts of the anticoagulant agent 24, the fixative agent
26, and optionally, the acid 28 including the ratio between the
compounds 22 and the final composition 30 are the same as described
above for the device 100 of the claimed subject matter. It is
preferred the compounds have been sterilized (e.g., by sterile
filtration). The method of the preloading step 204 may optionally
include freeze drying the compounds in the tube 12. The method 200
further includes inserting the closure 18 into the open end 14 of
the tube 12 (206). The method 200 further includes drawing a vacuum
inside the tube 12 to a predetermined level (208) using
art-disclosed methods. The amount of vacuum to be drawn is
dependent upon the nature and volume of the cells desired to be
collected and preserved. For example, for whole blood collection,
the vacuum should be drawn to a level that allows the pressure of
the whole blood to cause it to flow into and fill the tube 12 to
the desired level. The method 200 may optionally include providing
the components 32 conventionally used to collect and analyze the
cells 20. The components 32 are the same as for the device 100 of
the claimed subject matter as described above.
[0030] The method may also optionally include collecting the cells
20 using art-disclosed methods (e.g., venipuncture, use of a
lancet, etc.). It may optionally include screening the cells 20
using art-disclosed instruments such as flow cytometers (eg.,
FACScan, FACSCalibur by BD and EPICS by Beckman Coulter), other
hematology instruments (e.g., H3 by Bayer Corporation, the Beckman
Coulter STKS or Gen-S Systems, the Abbott Cell-Dyn 4000 Hematology
System, Bayer ADVIA 120 System, the Sysmex XE2100 System, and the
like. The screening of the cells may be for any purpose including,
without limitation, for HIV, HPV, hepatitis, leukemia, cancer, and
the like; other art-disclosed screening such as immunoassay, AIDS
panel, and the like; and screening by methods disclosed in commonly
U.S. Pat. No. 4,788,139 (Ryan) titled "Platelet aggregation
reagent, reagent container and method of determining platelet
aggregation in EDTA-anticoagulated blood", which is hereby
incorporated by reference. Cells 20 collected and preserved using
the claimed subject matter may undergo histological study in any
known conventional manner, such as through the use of paraffin
sectioning equipment, staining, mounting on slides, or other common
steps utilized prior to microscopic or other examination. The
claimed subject matter thus provides a safe, convenient, and
effective solution to collect and preserve cells for analysis.
[0031] It should be noted that the method and device of the claimed
subject matter may be used by those skilled in the art to preserve
antigenic sites on or within cells (or components thereof) derived
from any source including normal blood, bone marrow, lymph, or
solid tissues, or may be derived from abnormal tissues such as
leukemias or solid tissue cancers. The claimed subject matter may
also be utilized with any cellular component or biological material
that has at least one antigenic site.
[0032] It should be noted that in preferred embodiments of the
claimed subject matter cell clumping is prevented, light scattering
properties are preserved, antigenic sites are preserved, and
nucleic acids may be analyzed.
[0033] The foregoing detailed description has discussed only a few
of the many forms that the claimed subject matter can take. For
this reason, this detailed description is intended only by way of
illustration. It is only the following claims, including all
equivalents that are intended to define the scope of the claimed
subject matter.
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