| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Bioengineering, University of California San Diego, La Jolla, California 92093-0412; and 2 Heineman Medical Research, Charlotte, North Carolina 28235
 |
ABSTRACT |
|---|
 TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
This study was designed to determine the transport of subcutaneously injected viral-size colloid particles into the lymph and the vascular system in the hind leg of the dog. Transport of two colloid particles, with average size ~1 and 0.41 µm, respectively, and with and without leg rotation, was tested. Leg rotation serves to enhance the lymph flow rates. The right femoral vein, lymph vessel, and left femoral artery were cannulated while the animal was under anesthesia, and samples were collected at regular intervals after subcutaneous injection of the particles at the right knee level. The number of particles in the samples were counted under fluorescence microscopy by using a hemocytometer. With and without leg rotation, both particle sets were rapidly taken up into the venous blood and into the lymph fluid. The number of particles carried away from the injection site within the first 5 min was <5% of the injected pool. Particles were also seen in arterial blood samples; this suggests reflow and a prolonged residence time in the blood. These results show that particles the size of viruses are rapidly taken up into the lymphatics and blood vessels after subcutaneous deposition.
human immunodeficiency virus; dog
| |
INTRODUCTION |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
ACCIDENTAL EXPOSURE to human immunodeficiency virus (HIV) particles via needle sticks or cuts in the health care setting has generated considerable interest in the mechanism of viral transport and incorporation after a subcutaneous exposure (6, 11, 14, 19, 26). There is evidence indicating transmission of cancer cells into the lymph and vascular system, although these cells are bigger than viral particles (7, 8). This would suggest that if these cancer cells can be incorporated, the smaller viral particles would be absorbed with greater efficacy. Although the literature provides many examples of vascular and lymph incorporation (1, 7, 8), there is a lack of information about the time course of transport as an important aspect for devising effective strategies for treatment after accidental exposure. Fundamental questions have not been answered. How long do viral particles remain in the subcutaneous tissue space? Can their residence time be controlled by various methods that are known to influence lymph flow? Robicsek et al. (23) attempted to answer these questions in an earlier study by using 125I-labeled polystyrene beads. However, direct cannulation of the lymph duct and precise control of particle integrity prevented reaching a firm conclusion in regard to the actual particle movement into the lymphatic and vascular systems. Because of a marked improvement in particle technology, it is now possible to examine this question with an improved protocol.
The purpose of this study was to examine the transport of subcutaneously injected viral-size colloid particles into the lymph and vascular system. Colloid particles of two different sizes were tested. The transport at low and enhanced levels of lymph flow rates was examined, because this may prolong or shorten the time of absorption. To quantify the particle transport in both the vasculature and the lymphatics, fluorescent colloid particles were used.
| |
MATERIALS AND METHODS |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
Animals.
Ten dogs weighing 20-27.5 kg were anesthetized with pentobarbital
sodium (30 mg/kg), intubated, and maintained on positive-pressure ventilation throughout the experiment. The protocol was approved by the
Institutional Animal Care and Use Committee of Carolinas Medical
Center, Charlotte, NC, and follows the Guide for the
Care and Use of Laboratory Animals published by the
National Research Council. Each animal was surgically prepared by
cannulating the right femoral vein with a 16-gauge catheter (Angiocath)
and administration of heparin (0.3 mg/kg). The catheter was not tied,
so continuity of venous flow was allowed. Arterial blood samples were
collected from the contralateral femoral artery by using the same
technique. When necessary, a subdermal lymph duct was visualized after
subcutaneous injection of 0.5-1 ml of Evans blue dye at knee
level. The lymph channel parallel to the femoral vein was cannulated
with a 24-gauge catheter (Angiocath) and was permitted to drain (Fig.
1). Adjacent lymphatic ducts were ligated.
Lymph and blood samples were collected in 2.0- or 5.0-ml capped test
tubes, respectively.
|
Colloid particles.
A fluorocarbon colloid-particle suspension and a suspension of rigid
microspheres were used in the experiments. The colloid material
[ZY-15017 (perfluorooctyl bromide suspended in egg yolk phospholipid); Alliance Pharmaceuticals, San Diego, CA] is a
fluorocarbon emulsion which has 60% wt/vol and contains particles
(1-µm average diameter) covered with a phospholipid membrane (16, 17,
21). Its density is 1.92 g/ml, and the original concentration of
particles is 1.0 × 1022/ml.
In the analysis, however, only those clusters with diameters greater
than ~1 µm were included to optimize visibility and to improve
accuracy of the cluster counts. In the following analysis, a cluster 1 µm in diameter is counted as one particle. The emulsion ZY-15017 has about 1.5 × 1011 particles, as determined with
a hemocytometer, and the particles are close to a spherical shape. To
determine the concentration of ZY-15017 particles, the following
fluorescent labeling technique was used (12). A
10
3 mol/l stock solution of
PKH26-GL (Sigma Biosciences, St. Louis, MO) (3, 15, 24, 28, 29) was
added to the emulsions of ZY-15017 to a final concentration of
105 mol/l. The mixtures
were gently stirred in the dark for 5 min at room temperature.
Subsequently, the PKH26-GL/ZY-15017 mixture was added in equal volume
to 1% BSA and gently stirred for 1 min to stop the staining reaction.
The final concentration of stained ZY-15017 was 30% wt/vol perfluorocarbon.
Experimental protocol. After lymphatic, venous, and arterial cannulation, the tissue was stabilized for a period of ~15 min, with passive whole leg rotation in the first experiment and without leg rotation in the second experiment. The movement of the leg was carried out at steady state and by the same person. The rate of rotation was measured with a stopwatch. The leg rotation was maintained during the entire 45-min experimental period. Approximately 1.0 ml of the colloid solution was injected slowly (in 5-6 s) through a 25-gauge needle, the tip of which was positioned in the subcutaneous space at the middle level of the knee. After injection of the fluorescently labeled particles, lymph fluid was collected continuously over a total period of 45 min. The samples were placed about every 3-4 min into a new capped test tube. The venous blood samples were collected continuously during the first 5 min and were placed into another test tube about every 15 s. Thereafter, aliquots of ~5 ml were collected in longer intervals of 5 min over a period of 45 min. Arterial blood samples (each ~5 ml) were collected every 5 min after injection of the particles throughout the 45-min observation period. Lymph, venous, and arterial samples were stored at 4°C until measurements were made. The samples were sufficiently small so that there was no detectable effect on the central blood pressure of the dogs.
The density of lymph and blood was estimated as ~1 and 1.1 g/cm3, respectively, after the weight of several samples with predetermined volume was checked. The flow rates were determined by weighing the collected fluids and dividing its weight by the mass density and the collection time periods.Particle-density measurements. ZY-15017 colloidal particles were detected under a fluorescence microscope by using a ×25 water-immersion objective (numerical aperture = 0.6; Leitz, Wetzlar, Germany). Each sample was placed in a fluid layer (100-µm thick) between two glass coverslips. To record fluorescent images, the sample was illuminated with a 200-W mercury light source. The light was passed through a quartz collector, a heat filter (model KG-2; Carl Zeiss, Thornwood, NY), and a 515- to 560-nm-wavelength-excitation filter (Leitz, Rockleigh, NJ) to epi-illuminate the sample. Fluorescent emission from the sample was passed through a 580-nm-thick band-pass filter (Leitz) and recorded with a charge-coupled-device camera (model VI-470, Optronics Engineering, Goleta, CA). The number of particles was counted on the monitor by using a hemocytometer. The smallest diameter of a cluster which could be recognize in this setting was about D = 1 µm (~1 mm on the monitor) and counted as 1 particle. The number of particles contained in larger particle clusters was computed with the formula N = 0.6 × (a3/D3), where N is the number of particles and a is the diameter (in µm) of a cluster on the monitor. This formula assumes a packing coefficient of 60% for rigid, equal-sized spheres. The blood samples were diluted to 1% by adding normal saline, and then they were observed under fluorescence microscopy. Actual clusters may contain more (or fewer) particles, so the current measurements should be regarded as accurate only to within a factor of two to three, i.e., they are accurate to within an order of magnitude.
The L910128A microspheres were counted under a fluorescence microscope with a ×50 oil-immersion objective (numerical aperture = 1.0; Leitz). Each sample was placed in a fluid layer (100-µm thickness) between two glass coverslips. To record fluorescent images, the sample was illuminated with a 200-W mercury light source. The light was passed through a quartz collector, a heat filter (model KG-2; Carl Zeiss), and a 515- to 560-nm-wavelength-excitation filter (Leitz) to epi-illuminate the sample. Fluorescent emission from the sample was passed through a 580-nm-thick band-pass filter (Leitz) and recorded with a charge-coupled-device camera (model VI-470, Optronics Engineering). The number of particles was counted on the monitor. Before the number of particle was counted, the blood samples were centrifuged (4,000 rpm, 30 min) and separated into three fractions: plasma, buffy coat, and red blood cell pellet. The buffy coat was collected, resuspended in autologous plasma buffer (ratio 1:100), and observed under fluorescence microscopy, because pilot studies had shown that the buffy coat contained most of the fluorescent microspheres after centrifugation.Statistics. All results are expressed as means ± SE. Paired t-test or a one-way analysis of variance was used to test for statistically significant difference between groups. Differences between groups were considered significant at P < 0.05.
| |
RESULTS |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
Six experiments were carried out during leg rotation with
PKH-26-stained ZY-15017 colloid particles as tracer (Figs.
2 and 3).
Four experiments were carried out by using fluorescent L910128A microspheres and without leg rotation (Figs.
4 and 5).
|
|
|
|
Transport in hindlimb with leg rotation.
Peak lymph flow rate with leg rotation was ~1.0 × 101 ml/min at 6 min after
the injection; thereafter, the flow rate decreased to ~0.4 × 101 ml/min (Fig.
2A). The time course of particle
flux in the lymph samples indicates that the fluorescent particles
appeared already within ~3 min after subcutaneous injection of the
particles, and they were continuously seen in lymph fluid (Fig.
2B). There seemed to be two peaks of
particle flux at 3 and 27 min, but they were not significantly
different from the values during other collection times. During the
experiments, ~1 × 106
particles/min were continuously detected. At 45 min, the cumulative number of particles in lymph after the injection reached 8.8 ± 3.5 × 107 (Fig.
2C). This value is equivalent to
~0.1% of the total number of particles injected into the
subcutaneous region.
1 ml/s at 75 s after the
injection (Fig. 3A). During the
first 5 min, the blood samples were continuously collected every 15 s;
thereafter, they were intermittently collected every 5 min. For
clarity, only a selected number of measurement points are shown in
Figs. 3 and 5.
The colloidal particles already appeared in the venous blood samples at
~15 s after subcutaneous injection, and they were encountered in the
venous blood throughout the experiment (Fig. 3,
B and
C). There seemed to be three peaks
(at 75 s, and at 35 and 40 min; each value was ~0.5 × 108 particles/s) in particle flux
(Fig. 3C), but they were not
significantly different from the values at other time points. The
particle flux in the venous samples was ~0.1-0.2 × 108 particles/s. The accumulated
number of particles at 5 min after injection was 3.9 × 109 ± 9.4 × 108 particles, which is equivalent
to ~3% of the total number of injected particles (Fig.
3D).
A significant number of particles appeared also in arterial blood
samples ~10 min after subcutaneous injection (Fig.
3E), (~2.0 × 104
particles/mm3); this indicates
arterial reflux and a widening of the distribution of the injected particles.
Transport without leg rotation.
The lymph flow rate without leg rotation was smaller and
~0.2-0.4 × 101
ml/min (Fig. 4A). These values were
~20-40% of peak lymph flow rates with leg rotation. The
L910128A-emulsion microspheres appeared in the lymph first at ~4 min
after injection and were seen throughout the experiment (Fig.
4B). There appeared to be two peaks
of microsphere flux (at 8 and 24 min; Fig.
4B), but their values were not
significantly different from the flux values at other times. After a
period of ~4 min after the injection, ~2.5 × 106 microspheres/min were
continuously carried in each lymph sample. The cumulative number of
microspheres after the injection of microspheres gradually increased
(Fig. 4C), and, at 44 min after
injection, the number reached 3.1 ± 2.1 × 109 microspheres, which is
equivalent to ~0.1% of the total number of injected microspheres.
1 ml/s at ~15 s after
the injection (Fig. 5A). This value
and the time course of venous blood flow rate without leg rotation were similar to those with leg rotation. The microspheres appeared in venous
blood samples ~15 s after subcutaneous injection (Fig. 5,
B and
C). At 4 min 45 s after the
injection, no particles were seen in venous blood, although during
these periods there may have been numbers of microspheres that were
below the detection limit. The cumulative number of microspheres in the
venous blood samples 5 min after injection reached 1.0 ± 0.98 × 1011
microspheres (Fig. 5D). This value
is equivalent to ~4% of the total number of injected microspheres.
At 5 min after the injection, the venous samples were intermittently
collected, so no microsphere accumulation leaving the injection site
via the femoral vein could be determined. Microsphere concentration
encountered in arterial blood samples at 10 min after subcutaneous
injection reached ~2.9 × 104
microspheres/mm3 (Fig.
5E).
| |
DISCUSSION |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
With an increase in the numbers of HIV-infected patients, there is an increasing possibility that accidental exposure to HIV particles may occur via needle sticks or cuts in health care workers (6, 11, 11a, 14, 18, 19, 26, 27). According to several reports (4, 11a, 23), the average risk of HIV transmission to a health care worker after a needlestick exposure to HIV-infected blood is ~0.3-0.4%. Despite this risk, the mechanism of viral transport and incorporation after a subcutaneous exposure has not been established. Therefore, the purpose of the present study was to determine the transport into the lymph and vascular system of subcutaneously injected viral-size colloid particles. Using particles that on average are approximately equal in size to or even larger than virus particles, we examined the transport at low and enhanced levels of lymph flow rates, because this may prolong or shorten, respectively, the time of particle absorption (13).
The peak flow rate with leg rotation was ~1.0 × 101 ml/min, with a
steady-state flow rate under the same conditions of ~0.4 × 101 ml/min. The flow rate
without leg rotation was ~0.2-0.4 × 101 ml/min during the
experiment, although the flow rate seemed to be slightly increasing
with time. Garlick and Renkin (9) reported that the flow rate in the
dog's popliteal lymphatics (body weight 9-13 kg), with leg
rotation during 6-h observation, was ~0.36 × 101 ml/min, a value similar
to the current results.
In contrast, the venous flow rate was not different between the groups with and without leg rotation. The venous flow rate may be much less susceptible than is the lymph flow to the modest leg rotation. The decline in venous flow during the first 5 min may be partly explained by a pressure readjustment during continuous sample collections into a side port for the purposes of the particle accumulation estimations.
There are two different transport mechanisms of colloidal particle uptake into the rabbit hindlimb (12, 13). One is transport of the colloid suspension along extracellular interstitial fluid channels directly into the initial lymphatic vessels, and the other involves phagocytosis of colloid particles by macrophages, which in turn migrate into the initial lymphatic vessels and carry the colloid suspension via an intracellular pathway along the lymphatic vessels into the nodes. The number of particles carried initially after injection via an intracellular pathway was small, however, compared with the freely suspended particles in the early time period. Harmsen et al. (10) also suggested a role for macrophages in particle translocation from lung to lymph nodes (intracellular transport). In the present study, macrophages which had phagocytosed particles were observed in only a few samples. In the current protocol, there may be insufficient time for significant phagocytosis to occur in the tissue.
The average concentration of original ZY-15017 particles was 3.0 × 1011/ml. In each experiment, 0.5 ml of original ZY-15017 solution was injected, and so the total number of particles was 1.5 × 1011. On average, the total number of particles in lymph samples during the 45-min experimental period was ~0.1% of the total particles injected, whereas the total average number of particles in venous blood samples during the first 5 min was ~3% of total particles injected. According to the anatomy of dog's hindlimb (20), particles which were injected at the level of the knee are mainly absorbed into the lymphatics of the superficial medial trunk that is cannulated. Actually, the Evans blue dye was mainly absorbed into this superficial medial trunk, but most of the Evans blue dye that was injected subcutaneously at the dog's knee remained at the injection site for many hours. This observation is in line with the low lymph removal (~0.1%). In contrast, the amount of venous particle removal from the injection site during the first 5 min (~3%) was surprisingly large. One of the possible reasons for the high incorporation of particles into the venous system may be that the injection needle directly punctured some vessels of the microcirculation. In addition, the local injection of fluid volume may serve to increase interstitial pressure. The fact that particles were recognized in all six venous blood samples at 45 s after the injection indicated that inert viral-size particles may be absorbed into venous blood at an early time point in our two experimental settings. Particles also appeared in arterial blood samples at 10 min after the injection; this suggests that some particles were recirculating without absorption in other organs. Such an event would be accompanied by a significant spread of the particles into other parts of the circulation. Arterial samples at earlier times (~1-5 min) had undetectable levels of particles, which, in light of the resolution of the current measurement (50 particles/mm3), may still be associated with a considerable level of particle escape into the central circulation.
Previously, Robicsek et al. (23) investigated the incorporation of 125I-labeled 90-nm polystyrene beads into the lymphatics and the venous blood of the canine hindlimb. The average incorporation time of the beads was ~4 and 8 min in lymph and venous vessel, respectively. In their experiment, the precise quantitative values were difficult to estimate because of the labeling procedure and because of incomplete separation of particles from the suspending liquid. There was an initial peak of radioactivity (<1 min). This peak was excluded from the analysis, because it disappeared after repeated washes with 100% ethanol without any effect on the later peak caused by the radioactive polystyrene particles. But in light of the present data, it is possible that a part of the polystyrene beads may have been present in the first peak (at times <1 min).
Because the second set of experiments was carried out without leg
rotation, the lymph flow rates in this setting were ~20-40% of
the peak flow rate with leg rotation, and these values were slightly
less than the stable lymph flow rates with leg rotation. It was
remarkable that even gentle hand massage served to avoid the large
decrease of the lymph flow rate in the absence of leg rotation. Ikomi
et al. (12) had investigated the lymph flow rate of the rabbit hindlimb
with and without leg rotation during a 2-h period, without hand
massage. According to these measurements, the lymph flow rates with and
without leg rotation were 1.88 and 0.07 × 101 ml/h, respectively, and
thus the former was ~30 times higher than the latter. These authors
also examined the lymph flow rates of the rabbit hindlimb with and
without hand massage, while leg rotation was carried out in both
groups. The lymph flow rates were ~9.5 and 1.8 × 101 ml/h, with and without
hand massage, respectively, and the former was ~5.3 times higher than
the latter. These experimental results indicate that increased lymph
flow required hand massage of the skin surface.
In our second set of experiments, incorporation of microspheres into the lymph fluid and the venous blood was also observed at the early times. The total microsphere accumulation in the lymph samples over the 44-min experimental period was 0.1% of the total injected microspheres, and the total accumulation over a shorter period of 5 min in venous blood samples was ~4% of the total injected microspheres. These observations are in close agreement with the results of the first set of experiments. Thus, under both experimental conditions, the transport of particles of the size of viruses and larger, which requires a predominantly convective mode of transport rather than diffusion, leads to the escape of relatively large numbers of particles away from the injection site. More than 90% of the particles, however, remain at the injection site during a period of ~5 min.
By using a feline leukemia virus, we have investigated in cats several methods to prevent a virus infection after a needle stick or a cut exposure (22). The prevention of virus infection could not be achieved in both needle stick and cut exposure when 0.2% povidone-iodine was injected at the exposed area 20 s after the exposure; instead, prevention could only be achieved when 0.2% povidone-iodine was injected before or immediately after the exposure. These observations are in line with the present analysis; this suggests very early incorporation of particles into venous blood and lymphatics, thus underlining the potential need for both local and central treatment after accidental exposure.
The early transport of colloid particles into the vascular and lymphatic vessels relies largely on an extracellular pathway which depends on convective transport (i.e., solvent drag). Thus the particle uptake in the period immediately after injection is relatively insensitive with respect to the exact particle size in the submicrometer range. It is expected that virus particles, which are smaller than the particles used in the current study, will be carried in the tissue toward lymphatics and microvessels with great efficacy, leading to an enhanced escape compared with the levels reported in this study.
In conclusion, inert particles of a size similar to or slightly larger than HIV particles were rapidly taken up by the lymph and the vascular systems, and some particles were recirculated in the vascular system, thus suggesting a wider spread in the circulation.
When we consider the fate of HIV particles in the human body after accidental exposure to HIV particles via needle sticks or cuts in health care workers, most of the virus particles may be lysed by various proteases and be degenerated by phagocytic cells before incorporation into the lymph and vascular systems. But, according to our present results, the possibility still exists that some of the HIV particles may be rapidly incorporated into the lymphatic and vascular system and may infect T lymphocytes and other cells. This indicates that prevention of HIV infection after accidental exposure of a needle stick and cut contaminated with HIV-infected blood requires a rapid response with the aim of decreasing the HIV virus activity, both locally and centrally in the circulation.
| |
ACKNOWLEDGEMENTS |
|---|
This work was supported in part by the Heineman Foundation for Research, Educational, Charitable and Scientific Purposes, Inc., NY.
| |
FOOTNOTES |
|---|
Address for reprint requests and other correspondence: G. W. Schmid-Schönbein, Dept. of Bioengineering, Univ. of California San Diego, La Jolla, CA 92093-0412.
Received 15 December 1997; accepted in final form 10 December 1998.
| |
REFERENCES |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
1.
Anderson, J. L.,
N.- Rossing,
and
K. T. Drzewiecki.
Preoperative cutaneous lymphoscintigraphy in malignant melanoma.
Cancer
63:
77-82,
1989[Medline].
3.
Ashley, D. M.,
S. J. Bol,
C. Wangh,
and
G. Kannourakis.
A novel approach to the measurement of different in vitro leukaemic cell growth parameters: the use of PKH GL fluorescent probes.
Leuk. Res.
17 (10):
873-882,
1993[Medline].
4.
Centers for Disease Control and Prevention.
Case-control study of HIV sera conversion in health care workers after percutaneous exposure to HIV infected blood
France, United Kingdom, USA, January 1988-1994.
MMWR
44:
929-933,
1995[Medline].
5.
Estapor "Microspheres" booklet (revised). New material on fluorescents, new encapsulate, and narrow magnetics, nanoparticles (<50nm), 1995.
6.
Evrard, S.,
P. Meyer,
K. Haaften,
D. Christmann,
and
J. Marescaux.
Occupational risk to surgeons of unrecognized HIV infection in a low prevalence area.
World J. Surg.
17:
232-236,
1993[Medline].
7.
Fisher, B.,
and
E. R. Fisher.
Barrier function of lymph node to tumor cells and erythrocytes. I. Normal nodes.
Cancer
20:
1907-1913,
1967[Medline].
8.
Fisher, B.,
and
E. R. Fisher.
The interrelationship of hematogenous and lymphatic tumor cell dissemination.
Surg. Gynecol. Obstet.
122:
791-798,
1966[Medline].
8a.
Fluorescent Microspheres. Fishers, IN: Bangs Laboratories Inc., 1997. (In-house materials, note no. 19), p. 1-19.
9.
Garlick, D. G.,
and
E. M. Renkin.
Transport of large molecules from plasma to interstitial fluid and lymph in dogs.
Am. J. Physiol.
219:
1595-1605,
1970.
10.
Harmsen, A. G.,
B. A. Muggenburg,
M. B. Snipes,
and
D. E. Bice.
The role of macrophages in particle translocation from lungs to lymph nodes.
Science
230:
1277-1280,
1985
11.
HIV/AIDS: the global epidemic, December 1996.
Weekly Epidemiol. Rec.
72:
17-21,
1997[Medline].
11a.
HIV, seroconversion after occupational exposure despite early prophylactic zidovudine therapy.
Lancet
341:
1077-1078,
1993[Medline].
12.
Ikomi, F.,
G. Hanna,
and
G. W. Schmid-Schönbein.
Intracellular and extracellular transport of perfluorocarbon emulsion from subcutaneous tissue to regional lymphatics.
Artif. Cells Blood Substit. Immobil. Biotechnol.
22:
1441-1447,
1994[Medline].
13.
Ikomi, F.,
G. K. Hanna,
and
G. W. Schmid-Schönbein.
Mechanism of colloidal particle uptake into the lymphatic system: basic study with percutaneous lymphography.
Radiology
196:
107-113,
1995
14.
Ippolito, G.,
V. Puro,
and
G. Carli.
The risk of occupational human immunodeficiency virus infection in health care workers.
Arch. Intern. Med.
153:
1451-1458,
1993[Abstract].
15.
Khalat, A.-N.,
G. W. Vorbeck,
K. Bross,
L. Kerp,
and
K.-G. Peterson.
In vivo labeling of the spleen with a red fluorescent cell dye.
J. Immunol. Methods
165:
121-125,
1973.
16.
Klein, D. H.,
D. B. Burtner,
L. A. Trevino,
and
R. A. Arlauskas.
Particle size distribution of concentrated perfluorocarbon emulsions by sedimentation field flow fraction.
Biomaterials Artif. Cells Immobil. Biotechnol.
20:
859-864,
1992.
17.
Krafft, M. P.,
M. Postel,
J. G. Reiss,
Y. Ni,
T. J. Peluna,
G. K. Hanna,
and
D. Song.
Drop size stability assessment of fluorocarbon emulsions.
Biomaterials Artif. Cells Immobil. Biotechnol.
20:
865-868,
1992.
18.
Morris, K.
Increase reported in UK HIV-1 infections in 1996.
Lancet
349:
479,
1997[Medline].
19.
Palmer, D. L.,
B. L. Hjelle,
C. A. Wiley,
S. Allen,
W. Wachsman,
R. G. Mills,
L. E. Davis,
and
T. L. Merlin.
HIV-1 infection despite immediate combination antiviral therapy after infusion of contaminated white cells.
Am. J. Med.
97:
289-295,
1994[Medline].
20.
Pflug, J. J.,
and
J. S. Calnan.
Lymphatics: normal anatomy in the dog hind leg.
J. Anat.
105:
457-465,
1969[Medline].
21.
Riess, J. G.,
J. L. Dalfors,
G. K. Hanna,
D. H. Klein,
M.-P. Krafft,
T. J. Pelura,
and
E. G. Schutt.
Development of highly fluid, concentrated and stable fluorocarbon emulsions for diagnosis and therapy.
Biomaterials Artif. Cells Immobil. Biotechnol.
20:
839-842,
1992.
22.
Robicsek, F.,
G. D. Duncan,
J. W. Black,
T. N. Masters,
S. A. Robicsek,
and
H. E. Rice.
Prevention of retrovirus infection after injury with contaminated instruments: an experimental study.
Ann. Thorac. Surg.
52:
74-77,
1991[Abstract].
23.
Robicsek, F.,
G. D. Duncan,
T. N. Masters,
S. A. Robicsek,
and
H. E. Rice.
Can AIDS be prevented after injury with contaminated instruments?
Ann. Thorac. Surg.
49:
984-986,
1990[Abstract].
24.
Samlowski, W. E.,
B. A. Robertson,
B. K. Draper,
E. Prystas,
and
J. R. McGregor.
Effects of supravital fluorochromes used to analyze the in vivo homing of murine lymphocytes on cellular function.
J. Immunol. Methods
144:
101-115,
1991[Medline].
26.
Tokars, J. I.,
R. Marcus,
D. H. Culver,
C. A. Schable,
P. S. McKibben,
C. I. Bandea,
and
D. M. Bell.
Surveillance of HIV infection and zidovudine use among health care workers after occupational exposure to HIV-infected blood.
Ann. Intern. Med.
118:
913-919,
1993
27.
Update: trends in AIDS incidence, deaths, and prevalence-United States, 1996.
Morb. Mortal. Wkly. Rep.
46:
165-173,
1997[Medline].
28.
Wallace, P. K.,
L. D. Palmer,
D. P. Lalley,
E. S. Bolton,
R. B. Alexander,
P. K. Horan,
J. C. Yang,
and
K. A. Muirhead.
Mechanism of adoptive immunology: improved methods for in vivo tracking of tumor-infiltrating lymphocytes and lymphokine-activated killer cells.
Cancer Res.
53:
2358-2367,
1993
29.
Young, A. J.,
and
J. B. Hay.
Rapid turnover of the recirculating lymphocyte pool in vivo.
Int. Immunol.
7:
1607-1615,
1995
This article has been cited by other articles:
|
|
 |
|
  A. Szuba, W. S. Shin, H. W. Strauss, and S. Rockson The Third Circulation: Radionuclide Lymphoscintigraphy in the Evaluation of Lymphedema J. Nucl. Med., January 1, 2003; 44(1): 43 - 57. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
