U.S. patent number 3,788,305 [Application Number 05/298,983] was granted by the patent office on 1974-01-29 for intratracheal sampling device.
This patent grant is currently assigned to The United States of America as represented by the United States Atomic. Invention is credited to Hans Schreiber.
United States Patent |
3,788,305 |
Schreiber |
January 29, 1974 |
INTRATRACHEAL SAMPLING DEVICE
Abstract
An intratracheal sampling device comprising an inner collection
tube coextensively and retractably mounted within a hollow probe
for insertion within the larynx of a subject animal with the
collection tube in a retracted position. Depression of a plunger
mounted at the external end of the probe extends the collection
tube within the animal's trachea and at the same time activates
means for supplying wash fluid to the probe as well as vacuum means
communicating, via a sample collection vessel, with the collection
tube. Wash fluid is ejected in a jetting action through an annular
clearance between the distal end of the probe and the extended
collection tube. The ejected fluid, together with contained
exfoliated cells from the tracheal walls, is recovered in the
sample collection vessel after returning through the collection
tube.
Inventors: |
Schreiber; Hans (Oak Ridge,
TN) |
Assignee: |
The United States of America as
represented by the United States Atomic (Washington,
DC)
|
Family
ID: |
23152849 |
Appl.
No.: |
05/298,983 |
Filed: |
October 19, 1972 |
Current U.S.
Class: |
600/581; 604/159;
604/35 |
Current CPC
Class: |
A61B
10/02 (20130101) |
Current International
Class: |
A61B
10/00 (20060101); A61b 005/10 () |
Field of
Search: |
;128/2B,2F,240-241,276-278 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rosenbaum; Charles F.
Attorney, Agent or Firm: Anderson; Roland A. Horan; John A.
Hamel; Stephen D.
Claims
What is claimed is:
1. Apparatus for collecting cells from animal respiratory tracts
comprising:
a. an elongated hollow probe having a handle portion and a tapered
extension portion for insertion into the respiratory tract to be
sampled, said extension portion terminating in a wash liquid
discharge end;
b. a flexible sample collection tube having first and second ends,
said sample collection tube being slidably mounted within said
probe and selectively extensible from said wash liquid discharge
end thereof;
c. means for selectively extending said first end of said sample
collection tube from said wash liquid discharge end;
d. means for ejecting wash liquid from said wash liquid discharge
end of said probe;
e. means, in fluid communication with said second end of said
collection tube, for maintaining reduced pressure in said tube so
as to cause ejected wash liquid and exfoliated cels contained
therein to enter said first end of said tube and flow therethrough;
and
f. a collection chamber in fluid communication with said second end
of said collection tube for receiving sample material removed
through said collection tube.
2. The apparatus of claim 1 wherein said wash liquid discharge end
of said probe comprises a polytetrafluorethylene sleeve having an
internal diameter which is greater than the external diameter of
said sample collection tube, said sample collection tube extending
coaxially through said sleeve, wash liquid being ejected through
the annular clearance between said sleeve and said collection
tube.
3. The apparatus of claim 1 wherein said means for selectively
extending said first end of said sample collection tube from said
wash liquid discharge end comprises a plunger fixed to said tube
and slidably disposed within said handle portion of said probe.
4. The apparatus of claim 3 wherein said plunger activates said
means for ejecting wash liquid from said wash liquid discharge end
and said means for maintaining reduced pressure in said sample
collection tube.
5. The apparatus of claim 4 further including a timer for shutting
off said means for ejecting wash liquid from said wash liquid
discharge end and said means for maintaining reduced pressure in
said sample collection tube.
Description
BACKGROUND OF THE INVENTION
The invention relates generally to cell sampling apparatus and more
particularly to an intratracheal sampling device which uses washing
fluid under pressure to collect exfoliating cells from the tracheal
walls. It was made in the course of, or under, a contract with the
U. S. Atomic Energy Commission.
Several animal models suitable for experimental induction of
bronchiogenic carcinoma have been developed in recent years. These
open the way to study the etiology, pathogenesis, and morphogenesis
of neoplastic diseases of the respiratory tract, and should
ultimately result in refinements of existing diagnostic and
therapeutic procedures and the development of new ones.
Exfoliative cytology of the respiratory tract has become an
indispensable diagnostic tool for malignant and other diseases of
the airways. The usefulness of existing lung cancer models would be
increased if efficient means were developed for obtaining
exfoliated cells from the respiratory tracts of various laboratory
animals, such as rats and hamsters, used in studies of respiratory
carcinogenesis. Such means would help bridge the gap between
cytological and histological findings during development of lung
cancer in man, and should be useful in gaining a better
understanding of the sequence of events during the morphogenesis of
cancer by aiding in clarifying the relationship between metaplasia,
atypia, and malignancy, and separating reversible from irreversible
"precancerous" lesions.
The success of diagnostic studies of the above type will depend
largely upon the existence of techniques and apparatus for
efficiently and repeatedly collecting exfoliated cells from the
lower respiratory tract. Existing equipment and methods for lung
lavage do not fully meet such requirement, however. Existing
methods involve sequentially filling one lung with wash liquid and
then removing the liquid while oxygen is supplied to the remaining
lung. Such methods are slow, complicated, yield an excessively
dilute suspension of cells, and produce adverse side effects in the
animal being tested.
It is, accordingly, a general object of the invention to provide
apparatus for efficiently collecting exfoliated cells from the
lower respiratory tract.
Other, more particular objects of the invention will become
apparent upon examination of the specification and appended
drawing.
SUMMARY OF THE INVENTION
In accordance with the invention, an intratracheal sampling device
is provided for collecting exfoliated cells from the lower
respiratory tracts of laboratory animals. The sampling device
comprises a flexible inner collection tube coextensively and
retractably mounted within an elongated hollow probe suitable for
insertion within the larynx of the animal from which a sample is
desired. A manually operated plunger is mounted within the probe
handle for extending and retracting the collection tube and for
actuating means for supplying wash fluid to the probe as well as
vacuum means communicating, via a collection vessel, with the
collection tube. Wash fluid is ejected in a jetting action through
an annular clearance between the distal end of the probe and the
extended collection tube. The ejected fluid, together with
exfoliated cells from the tracheal walls, is recovered in the
sample collection vessel after passing through the collection tube.
Use of such apparatus to obtain cell samples is fast, simple,
yields a relatively concentrated suspension of cells, and causes a
minimal trauma to the subject animal.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, a sampling device made in accordance
with the invention is shown in its operating mode. The sampling
device includes a hollow elongated probe 1 having a handle portion
2 and a tapered extension 3, a manually actuable plunger 4 slidably
mounted within handle portion 2, and a flexible sample collection
tube 5 extending axially through the plunger and tapered extension
3. Sample collection tube 5, which is fixed to plunger 4 and
movable therewith, is slidably traversible through a slide seal 6
provided between handle portion 2 and tapered extension 3 to
prevent leakage of wash fluid into the handle portion. As shown,
the sample collection end 7 of sample collection tube 5 extends
from the distal end of tapered extension 3 when plunger 4 is
depressed. A sleeve 8 of polytetrafluorethylene is provided at the
distal end of extension 3 for insertion into the animal's larynx up
to the point shown by broken line 9. Sleeve 8 and collection tube 5
are sized to form a liquid supply and retrieval nozzle wherein wash
liquid jetted outwardly through the annular passage between the
sleeve and collection tube is retrieved through the end 7 of the
collection tube extending beyond the end of the sleeve.
A plunger extension 11 extends axially along the outside of handle
portion 2 in alignment with switch 12 which is fixed to the handle.
Depression of plunger 4 causes plunger extension 11 to close switch
12, thereby activating respective vacuum and wash liquid injection
means 13 and 14. Timer 15 terminates the vacuum and injection of
wash liquid after a suitable interval. Wash liquid injection means
14 supplies wash liquid to the interior of tapered extension 3 by
means of a flexible conduit 16. The wash liquid thus supplied
travels to the distal end of extension 3 where it discharges, in a
jetting action, through the annular spacing between sleeve 8 and
extended sample collection tube 5. The wash liquid thus discharged
is recovered through tube 5 as indicated by the flow arrows in the
drawing. Vacuum means 13 communicates, via vacuum conduit 17 and
sample collection vessel 18, with end 19 of sample collection tube
5, thereby facilitating recovery of wash liquid and exfoliated
cells suspended therein. Sample collection vessel 18 acts as a trap
where a sample 20 of wash liquid and exfoliated cells is recovered
for study.
In operation, the animal from which the trachael washing is to be
taken is anesthetized, placed in an inclined position with its
mouth held open and its larynx brought into view. Sleeve 8 is then
inserted into the upper part of the larynx and plunger 4 depressed
to extend collection tube 5 about 15 mm out of the end of the
sleeve. At the end of the depression stroke of plunger 4, switch 12
is closed and vacuum and wash fluid injection means 13 and 14
activated, causing, in a 5-second interval, 2 ml of wash liquid to
be jetted through sleeve 8 and then recovered through tube 5.
Shearing forces caused by the jetting motion of the wash liquid
causes exfoliated cells to be swept into the wash liquid, aspirated
into collection tube 5, and delivered to sample collection vessel
18. The vacuum is maintained at a constant value which is
sufficient to remove all wash liquid delivered but insufficient to
cause a negative pressure buildup in the lung. Conventional
specimen fixing procedures as described below are applied to the
cells collected in the trap.
After each sampling procedure, the sampling device is removed from
the animal being tested and 6 ml of prefixative is aspirated
through collection tube 5 to wash off any cells remaining in the
tube and transfer them to collection vessel 18. The prefixative is
a solution of 2 ml of melted Carbowax (Carbowax R1540, polyethylene
glycol available from Union Carbide Corporation, New York, N. Y.)
in 100 ml of 50 percent ethanol. The upper perforated stopper 21
can be transferred to another collection vessel for further use
after addition of the prefixative.
The recovered specimen is prefixed in the 50 percent ethanol -- 2
percent Carbowax solution for at least 2 hours and then centrifuged
for 5 minutes at 240 g and 25 minutes at 960 g to collect the cells
therein on a coverslip at the bottom of the collection vessel. Most
of the supernatant is pipetted off and the coverslip allowed to dry
while the Carbowax forms on opaque, waxy, protective film over its
surface. The specimens are then postfixed in 95 percent ethanol for
1 hour after which they are placed in running tap water for 5
minutes to remove the Carbowax, stained, and mounted face down on
microscopic slides. Before use, the coverslips are washed
thoroughly until they are coated with water, and a thin layer of
albumin-glycerin is rubbed on the surface facing the specimen.
Proper operation of the subject sampling device is achieved only
when the wash liquid is returned through a centrally located tube 5
as previously described in reference to the drawing so that a
maximum shearing action is provided by the jetted wash liquid. In
addition, collection tube 5 must be more flexible than sleeve 8 and
retractable therein. End 7 of collection tube 5 must be extendable
beyond the end of sleeve 8 a limited distance so that flooding in
the region of liquid discharge does not occur. An extension
distance of 15 mm has been found effective in practice.
EXAMPLE I
Tracheal washings were obtained from rats and hamsters from 1 to 5
times at intervals of 1 to 14 days. Consistently, 1-2 .times.
10.sup.5 cells were obtained from those animals when 2 ml of wash
liquid and short methoxyflurane narcosis were used. Cell yield
appeared to depend on a number of variables such as the amount of
washing fluid used or the type and duration of anesthesia. The cell
types obtained included ciliated cells, goblet cells, clusters and
sheets of respiratory cells, alveolar cells, polymorphonuclear
leukocytes, and squamous cells. The relative frequency with which
the respective cell types appeared is shown in the following
table.
TABLE
Frequency of Appearance of Different Cell Types in Tracheal
Washings from Rats and Hamsters
Relative Frequency (%).sup.a Cell Type Rats Hamsters Ciliated cells
13 (.+-.3.1) 6.8 (.+-.1.7) Goblet cells 0.2 (.+-.0.2) 0.1 (.+-.0.2)
Unidentified columnar cells 10 (.+-.1.7) 4.7 (.+-.2.3) Alveolar
cells 25.6 (.+-.5.2) 41 (.+-.5.4) Polymorphonuclear leukocytes 1.1
(.+-.1.1) 5.3 (.+-.2.5) Unidentified noncolumnar cells 27.4
(.+-.4.5) 12.6 (.+-.2.5) Nuclei 23.1 (.+-.3.9) 28.2 (.+-.7.4)
Squamous cells 0.3 (.+-.0.6) 1.4 (.+-.1) .sup.a A total of 200
cells were counted from each tracheal washing. Samples were
obtained from 10 rats and 10 hamsters. Figures in parentheses
indicate the standard deviation of the percentage.
To determine whether the intratracheal washings could be performed
repeatedly on a single animal without damaging the tracheal
epithelium or initiating an inflammatory response, histological
examinations of the respiratory trace tissues were made after
single or repeated intratracheal washing. No signs of inflammation
or injury of lung or tracheal tissues were found. More than 1000
cytology samples were obtained in rats and hamsters without any
deaths occuring as a result of the sampling. Even those animals
bearing lung tumors tolerated repeated washings without apparent
ill effects.
EXAMPLE II
The feasibility and usefulness of the subject sampling device in
obtaining samples for studies of lung tumor development were
demonstrated by following the cytological changes observed in the
tracheal washings of a hamster which had been intratracheally
injected with a massive dose of carcinogen.
The exfoliative cytology obtained from this hamster at 1.5, 5, and
6 months after the start of the experiment were correlated with the
histopatholgical findings. At 6 weeks (after 5 weekly intratracheal
injections of benzo a pyrene) many dyskaryotic squamous cells
appeared in the tracheal washing. The cell size varied considerably
and was sometimes two- to three-fold larger than normal. The
cellular shape was elongated, polygonal, round, or quite irregular,
and the cytoplasm stained red or orange. The variation in size and
shape and the hyperchromasia of the nuclei were very pronounced.
These dyskaryotic cells persisted in all the following tracheal
washings and might have shed from the squamous cell carcinomas
found at autopsy 4-5 months later. Five months after the experiment
began, another cell type appeared in the tracheal samples. These
cells were round or cuboidal and showed occasionally beaded
arrangement. The large nuclearcytoplasmatic ratio, the coarse
chromatin arrangement of the hyperchromatic nuclei, and the
variation in nuclear size were also characteristic of this cell
type. In the ninth tracheal washing at 6 months (immediately before
the hamster was killed), cells and clusters were found that closely
resemble the morphological characteristics of the tracheal sarcoma.
The cells were typically spindle-shaped and their cytoplasm stained
light purple. The elongated nuclei varied in size and showed dark
chromatin clumps. The clusters had a whorled arrangement of cells
that corresponded to the histological pattern of the sarcoma.
* * * * *