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Previous Article | Next Article 
Antimicrobial Agents and Chemotherapy, September 1998, p. 2299-2303, Vol. 42, No. 9
0066-4804/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Activity of Voriconazole Combined with Neutrophils or Monocytes
against Aspergillus fumigatus: Effects of Granulocyte
Colony-Stimulating Factor and Granulocyte-Macrophage
Colony-Stimulating Factor
Shefali
Vora,1
Sharda
Chauhan,1
Elmer
Brummer,1,2,3 and
David A.
Stevens1,2,3,*
California Institute for Medical
Research1 and
Division of Infectious
Diseases, Department of Medicine, Santa Clara Valley Medical
Center,2 San Jose, and
Stanford
University School of Medicine, Stanford,3
California
Received 12 January 1998/Returned for modification 8 May
1998/Accepted 11 June 1998
 |
ABSTRACT |
Voriconazole (VCZ) was tested for antifungal activity against
Aspergillus fumigatus hyphae alone or in combination
with neutrophils or monocytes. Antifungal activity was measured as
percent inhibition of hyphal growth in assays using the dye MTT
[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] or
XTT
[2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide]. With both assays, VCZ inhibited hyphal growth at concentrations of <1
µg/ml and was almost as active as amphotericin B. VCZ (0.6 µg/ml)
was sporicidal, as was amphotericin B (0.4 µg/ml). With both the
MTT and XTT assays, neutrophils alone inhibited hyphae; when
combined with VCZ, there was additive activity. Both granulocyte colony-stimulating factor- and granulocyte-macrophage
colony-stimulating factor (GM-CSF)-treated polymorphonuclear
neutrophils (PMN) had enhanced inhibition of hyphal growth. Moreover,
such treatment of PMN also enhanced the collaboration of PMN with VCZ.
Monocytes inhibited hyphal growth. When VCZ was combined with monocytes or monocytes were treated with GM-CSF, inhibition was significantly increased, to similar levels. However, the combination of VCZ with
GM-CSF treatment of monocytes did not significantly increase the
high-level inhibition by monocytes with either agent alone.
| |
INTRODUCTION |
Aspergillosis continues to be a
frequent and difficult-to-treat fungal infection in certain
immunocompromised patients (4). Although most
Aspergillus species are susceptible to amphotericin B (AmB)
or itraconazole in vitro (3), development of new antifungal agents with less toxicity, better solubility, and desirable
pharmacokinetics is important. Of potential interest is the development
of a new oral wide-spectrum triazole, voriconazole (VCZ), which has in vitro activity against Aspergillus species (10).
Previously, we have reported synergy of phagocytic cells with
fluconazole for enhanced killing of Candida albicans
(1, 5, 6), which reflects in vivo efficacy. Here, we tested the possibility that phagocytic cells could collaborate with VCZ for
enhanced antifungal activity against Aspergillus fumigatus. Moreover, we investigated the effects that granulocyte
colony-stimulating factor (G-CSF) and granulocyte-macrophage
colony-stimulating factor (GM-CSF) treatment might have on antifungal
activity of neutrophils or monocytes for A. fumigatus and
possible collaboration with VCZ for enhanced antifungal activity.
| |
MATERIALS AND METHODS |
A. fumigatus.
Two clinical isolates (92-270 and 96-92)
were used principally in these studies. Isolates were grown on agar
slants at 35°C and then allowed to form conidia at room temperature
for 24 to 48 h. Conidia were harvested in distilled water, washed,
diluted in saline, and counted. Conidial suspensions consisted
primarily of single conidia (95%); the remainder were clumps of two or
three conidia. These were dispensed into 24-well tissue culture plates or 96-well microtest plates. Over 90% germinated when incubated overnight in RPMI 1640 at 26 to 37°C; hyphal lengths ranged up to 10 times the diameter of a conidium. For studies on hyphae, material from
overnight growth at 30°C (germlings) was used.
Activity of drugs on conidia was assessed by incubation of conidia in
RPMI 1640 at 103/well in a microtest plate and subculturing
of well contents on blood agar plates.
MTT and XTT.
Inhibition of hyphal growth was measured by the
colorimetric MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide] (Sigma, St. Louis, Mo.) assay (8). MTT that was
metabolized to formazan by viable hyphae was extracted with acidified
isopropanol, and absorbance (A) was measured at 570 nm
(A570) with a Shimadzu (Kyoto, Japan) UV 160 spectrophotometer. Percent inhibition of growth was calculated by the
formula {[A (control) 
A
(experimental)]/A [control]} × 100.
Inhibition of hyphal growth was also measured by the colorimetric
XTT-plus-coenzyme Q method (9). XTT
[2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] sodium salt at 0.5 mg/ml, coenzyme Q
(2,3-dimethoxy-5-methyl-1,4-benzoquinone) at 0.04 mg/ml, and
phosphate-buffered saline (PBS) (pH 7.4) constituted the test solution.
Viable cells reduce XTT to a reduced soluble form with a color change
from yellow to orange. Absorbance of XTT solution alone at 410 nm was
subtracted from absorbance of metabolized XTT in culture supernatants
at 410 nm to give the change in absorbance (
A), evaluated
by a Dynatech (Chantilly, Va.) MR250 microtest plate reader. Percent
inhibition was calculated by the formula {[A (control) A (experimental)]/A [control]} × 100.
VCZ and AmB.
VCZ (Pfizer, Groton, Conn.) was dissolved in
dimethyl sulfoxide and then diluted with distilled water to 2 mg/ml and
stored at 4°C. Desired dilutions were made from the stock solution
with RPMI 1640. AmB (Fungizone; Squibb and Sons Inc., Princeton, N.J.), kept refrigerated or frozen and protected from light in distilled water
at 1.6 mg/ml, was diluted in RPMI 1640 to give appropriate concentrations for testing.
G-CSF and GM-CSF.
Recombinant methionyl human G-CSF
(Filgrastim) was provided by Amgen, Thousands Oaks, Calif. G-CSF at
108 U/mg of protein was supplied at 0.3 mg/ml, and
appropriate dilutions from this stock were made in RPMI 1640. Recombinant human GM-CSF (Leukine, Sargramostim) was produced and
supplied by Immunex Corp., Seattle, Wash. GM-CSF (0.5 mg/ml; 1.5 × 108 IU/mg of protein) was diluted to 7.5 × 105 IU/ml in RPMI 1640 and stored at 80°C.
Neutrophil assays.
Polymorphonuclear neutrophils (PMN) and
peripheral blood mononuclear cells (PBMC) were isolated from
heparinized blood by sedimentation in 6% dextran-70 followed by
density gradient centrifugation on Histopaque 1077 (Sigma). For the MTT
assay, PMN were suspended to 2 × 106/ml of CTCM (RPMI
1640 plus 10% fresh human serum), and 1 ml was added to wells
containing germinated conidia (106/well), giving an
approximate effector-to-target (E/T) ratio of 10:1. Some sets of
quadruplicate cultures received 0.01 ml of a G-CSF dilution. Other sets
of quadruplicate cultures without PMN, with PMN, or with PMN and G-CSF
received 0.01 ml of AmB or VCZ to the desired final concentrations of
drugs.
After 24 h of incubation at 37°C in a CO2 incubator,
cultures were harvested into 15-ml conical centrifuge tubes with
distilled water to lyse PMN. Washed hyphae from each well were
incubated in 1 ml of RPMI plus MTT (0.5 mg/ml) for 3 h at 37°C.
Following incubation, hyphae were pelleted by centrifugation,
supernatants were aspirated, and metabolized MTT (formazan) in each
tube was extracted with acidified isopropanol for 5 h at 37°C.
Solubilized formazan from each tube was transferred to individual wells
of a 96-well flat-bottom microtest plate, and absorbance was measured at 570 nm.
For the XTT assay, germinated conidia (1 × 103 to
5 × 103/well) in 96-well microtest plates were
centrifuged in situ (400 × g; 10 min), supernatants
were aspirated, and 0.2 ml of PMN at 2.5 × 105 to
2 × 106 per ml of CTCM was added per coculture well,
giving 5 × 104 to 4 × 105 per well,
respectively. Some cocultures received VCZ, G-CSF, or GM-CSF alone,
while other sets of cocultures received G-CSF plus VCZ or GM-CSF plus
VCZ. Following incubation at 37°C for 24 h in a CO2
incubator, microtest plates were centrifuged, supernatants were
aspirated, and 0.2 ml of distilled water per well was added. The
centrifugation and washing step was repeated once more. Finally, 0.2 ml
of XTT test solution per well was added, and cultures were incubated
for 1 h at 37°C. The microtest plate was centrifuged again, 0.1 ml of supernatant from each well was transferred to a well of a new
plate, and absorbance at 410 nm was recorded.
Monocyte assay.
PBMC at 5 × 106/ml of CTCM
were dispensed at 1 ml per well of 24-well tissue culture plates and
then incubated for 2 h at 37°C in a CO2 incubator.
After incubation, nonadherent cells were aspirated and wells were
washed once with RPMI 1640. Monocyte monolayers in 1 ml of CTCM were
challenged with 1 ml of germinated conidia (104/ml). To
some sets of duplicate cultures, 0.01 ml of GM-CSF was added to give
the desired final concentrations. Other sets of duplicate cultures
without monocytes, with monocytes, or with monocytes plus GM-CSF
received 0.01 ml of VCZ to give the desired final concentrations. After
cultures were incubated for 24 h at 37°C in a CO2
incubator, they were harvested and processed as described above for the
PMN MTT assay.
Statistical analysis.
Student's t test was used
for statistical analysis of data, and significance was set at
P of <0.05. The GB-STAT program (Microsoft, Redmond, Wash.)
for Bonferroni's adjustment to the t test was used where
appropriate.
| |
RESULTS |
Preliminary tests.
Initial experiments determined the
parameters required for optimal results in the MTT assay. Germination
and incubation of increasing numbers of conidia in wells of 24-well
tissue culture plates showed that absorbance of the solubilized
metabolic product of MTT metabolism increased linearly with the number
of conidia (Fig. 1). These results
suggested that reliable results would be obtained by testing the
antifungal activities of drugs or phagocytic cells in wells of tissue
culture plates.
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FIG. 1.
Inoculum size and MTT metabolism by A. fumigatus (isolate 92-270) in 12-well tissue culture plates. The
numbers of conidia per well at time zero are given on the x
axis. Conidia in RPMI 1640 were incubated for 24 h at 37°C. The
y axis shows absorbance by 1 ml of metabolized MTT (means
and standard deviations of four samples) measured at 570 nm with a
spectrophotometer.
|
|
Initial experiments with the XTT assay were done with a range of
conidium inocula, which were cultured in wells of a 96-well microtest
plate at 37°C for 24 h in RPMI 1640. In the XTT assay, there was
a linear relationship between the metabolism of XTT and the inoculum
size, as shown in Fig. 2. This in situ
method was less complicated and more sensitive than the MTT method.
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FIG. 2.
Inoculum size and XTT metabolism by A. fumigatus (isolate 96-92) in microtest plate wells. The numbers of
conidia per well at time zero are given on the x axis.
Conidia in RPMI 1640 were incubated for 24 h at 37°C. The
y axis shows absorbance by 0.1 ml of metabolized XTT (1 h at
37°C) by hyphae (means and standard deviations of four samples)
measured at 410 nm with a microtest plate reader.
|
|
Activity of VCZ for conidia.
VCZ at 0.6 to 5.0 µg/ml and AmB
(0.4 to 5.0 µg/ml) in RPMI 1640 at 26 or 37°C for 24 or 48 h
were each fungicidal for conidia, i.e., there was no growth in
subculture. Microscopic examination showed that the conidia
did not germinate at these concentrations; however, lower,
nonfungicidal concentrations of these drugs (VCZ, 
0.4 µg/ml; AmB,
0.2 µg/ml) did not prevent germination.
Activity of VCZ with or without PMN against germlings: MTT
assay.
VCZ at 0.5 µg/ml in the MTT assay caused significant
inhibition (41%) of hyphal growth in 24 h (Table
1). In a total of four experiments with
1 × 105 to 2 × 105 germlings/well,
VCZ at 0.5 µg/ml inhibited growth by 50% ± 7%. PMN alone inhibited
hyphal growth of A. fumigatus by 30%. When VCZ and PMN were
combined, inhibition (75%) was additive (Table 1). By contrast, the
combination of AmB and PMN did not increase inhibition over that of AmB
alone. Whether this was due to the highly effective activity of AmB
alone or to some other effect remains to be determined.
Activity of VCZ with or without PMN: XTT assay.
At low VCZ
concentrations and a low E/T ratio (10:1), the inhibitory activities of
PMN (18%) and VCZ (32%) were more than additive when combined in
culture (Table 2). Similar results were
obtained in two other experiments. In a total of three experiments with
1 × 105 to 3 × 105 germlings/well,
VCZ at 0.05 µg/ml inhibited growth of isolate 96-92 by 34% ± 5%.
VCZ at 0.5 µg/ml inhibited growth by 97% under these conditions. In
two experiments, isolate 92-270 was inhibited by 67% ± 7% by 0.05 µg of VCZ per ml.
In an experiment with isolate 92-270 and a smaller inoculum (2 × 103/ml), VCZ alone at 0.01, 0.05, and 0.1 µg/ml inhibited
growth by 62, 72, and 86%, respectively (all P values were
<0.01 compared to medium alone). At an E/T ratio of 25:1 in that
experiment, PMN inhibited growth by 46% (P < 0.01)
and PMN combined with VCZ produced 78, 94, and 100% inhibition,
respectively, each value being significantly (P < 0.05) greater than PMN alone or the respective VCZ concentration alone.
At a 400:1 E/T ratio, VCZ at 0.1 µg/ml boosted an already
potent inhibition by PMN (72%) to 98% (P < 0.01). In
some experiments (not shown), we found that PMN activity alone could be
quite variable versus hyphae and even could be low with high E/T
ratios. The variables responsible could have been the aspergillus
strain, the PMN donor, and the germling size (which could vary after
24 h of incubation). However, as this study will show, even low
levels of PMN activity can be boosted by VCZ, and, as detailed below,
by immunostimulants.
Effect of G-CSF or GM-CSF on PMN activity and further studies of
E/T ratio: XTT assay.
Treatment of PMN with G-CSF or GM-CSF during
the coculture period with germlings resulted in enhanced inhibitory
activity compared to control PMN (Table
3); inhibition by PMN alone (11%) increased to 40% when G-CSF (500 ng/ml) was present and to 34% when
GM-CSF (500 U/ml) was present. At the same E/T ratio in other experiments, PMN inhibition of 6% significantly increased to 31 and
24% when lower doses of G-CSF (100 ng/ml) or GM-CSF (100 U/ml), respectively, were present (P was <0.05 for both).
When the parameters in the experiments were changed, e.g., an E/T ratio
of 25:1, PMN inhibition increased, as did inhibition by G-CSF- or
GM-CSF-stimulated PMN (Fig. 3). At an E/T
ratio of 400:1, inhibition by PMN alone (72%) increased to 89% when
G-CSF (100 ng/ml) was present and was increased slightly by 100 U of GM-CSF per ml, significantly increasing only by 500 U of GM-CSF per ml
(to 97%) (data not shown).
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FIG. 3.
Effects of G-CSF and GM-CSF on antifungal activity of
PMN for hyphae of A. fumigatus (isolate 96-92). Percent
inhibition of hyphal growth by PMN or PMN in the presence of G-CSF (100 ng/ml) or GM-CSF (100 U/ml) is given on the vertical axis. The E/T
ratio was 25:1. Data from two experiments are given. Both G-CSF-treated
and GM-CSF-treated PMN produced significantly (P < 0.01) greater inhibition than did untreated PMN.
|
|
Interaction of stimulated PMN with VCZ: XTT assay.
At an E/T
ratio of 10:1, where PMN activity alone was negligible, VCZ alone at
0.1 µg/ml inhibited growth by 73% and boosted inhibition by G-CSF
(500 ng/ml)-treated and GM-CSF (500 U/ml)-treated PMN from 38 and 18%,
respectively, to 89 and 83% (P was <0.01 for either
treatment versus PMN alone).
With the XTT assay and a 50:1 E/T ratio, inhibitory activity of PMN
(56%) collaborated with VCZ at 0.01 µg/ml (34% inhibition) for an
additive effect on hyphal growth (84%) (Table
4). Compared to untreated PMN, G-CSF- and
GM-CSF-treated PMN had significantly increased antifungal activities,
of 95 and 91%, respectively. Inhibition of growth by G-CSF- or
GM-CSF-treated PMN plus VCZ was significantly greater than inhibition
by untreated PMN plus VCZ. Conversely, inhibition by G-CSF- or
GM-CSF-treated PMN was boosted by VCZ; this was significant for GM-CSF
but not G-CSF, possibly because the G-CSF-treated PMN were so
inhibitory already. At an E/T ratio of 400:1, the potent PMN plus VCZ
combination yielding 98% inhibition was only slightly increased by
GM-CSF (to 99%), and this required 500 U/ml.
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TABLE 4.
Collaboration of G-CSF- and GM-CSF-treated PMN with VCZ
for activity against A. fumigatus hyphae: XTT assay
|
|
Activities of VCZ and PMN with or without G-CSF or GM-CSF: MTT
assay.
MTT results were consistent with the above observations. At
a low E/T ratio (10:1), where PMN inhibition alone was low and variably
significant, G-CSF-treated PMN collaborated with VCZ (0.5 µg/ml) for
increased inhibition of hyphal growth. In this experiment, PMN were not
inhibitory alone, VCZ (0.5 µg/ml) inhibited growth by 50%, and G-CSF
(500 ng/ml)-treated PMN inhibited growth by 55% (P of
<0.01 compared to PMN); this increased to 77% with VCZ (P
of <0.05 to 0.01 versus VCZ or G-CSF PMN alone). In another experiment, VCZ inhibition was the same, GM-CSF (100 U/ml)-treated PMN inhibited growth by 61%, and the combination
gave 78% inhibition.
Activity of VCZ and monocytes with or without GM-CSF: MTT
assay.
Monocyte monolayers challenged with germinated conidia at a
high E/T ratio (50:1) inhibited hyphal growth by 59% (Table
5). Monocyte activity is sensitive to
culture conditions; with XTT assays, 96-well plates, and other times of
incubation and adherence conditions, less monocyte activity was
demonstrated (data not shown). VCZ alone had an effect similar to
monocytes alone under the present study conditions (Table 5), i.e.,
inhibition of 58%. Similar results were obtained in a second,
identical experiment.
When the combination of monocytes plus VCZ was challenged with hyphae,
inhibition was increased to 79%, greater than by either agent alone.
GM-CSF treatment of monocytes significantly increased their inhibition
of hyphal growth, from 59 to 83% (Table 5). Similar results were
obtained in a second experiment. However, the combination of
GM-CSF-treated monocytes and VCZ did not increase the inhibition of
hyphal growth above that of GM-CSF-treated monocytes alone. In other
experiments (not shown), as would be expected, G-CSF had no effect on
monocyte activity.
| |
DISCUSSION |
We report here for the first time, to our knowledge, that VCZ (0.6 µg/ml) is fungicidal for conidia of A. fumigatus in vitro. These findings have implications for prophylactic therapy in patients at high risk for pulmonary aspergillosis.
Others using the broth macrodilution method (7) or the agar
dilution method (10) have reported that VCZ (0.5 µg/ml)
has in vitro activity against A. fumigatus hyphae. Using the
MTT and XTT assays, we have confirmed these results. Moreover, we
have demonstrated the utility, simplicity, and objectivity
of
and data for statistical analysis provided bythe microtest
plate XTT assay.
We report for the first time that under the appropriate
conditions, PMN or monocytes and VCZ collaborate additively in
inhibiting hyphal growth of A. fumigatus in a 24-h assay.
These in vitro results may partially explain the clinical efficacy of
VCZ in acute invasive aspergillosis (2).
Treatment of PMN with G-CSF has been reported to increase their
activity against hyphae of A. fumigatus in a short-term
assay (12). Using a 24-h coculture system with G-CSF, we
have obtained similar results. In addition, we report here that GM-CSF
treatment of PMN also significantly increases the inhibitory activity
against hyphae of A. fumigatus. Moreover, this boost in
activity due to these CSFs also significantly increases collaboration
with VCZ compared to control PMN plus VCZ.
At higher E/T ratios, PMN activity is greater and the effects of the
CSFs are proportionally smaller. This would suggest a greater
importance of the effects of CSFs clinically in combating infection
when there are less PMN available at the site of infection, i.e., in
neutropenic states. Thus, the CSFs may not only increase cell numbers
but may also have their greatest enhancing effects on individual cell
functions at times when cell numbers are low.
Monocyte monolayers significantly inhibited hyphal growth by 59% when
challenged for 24 h, and GM-CSF treatment significantly increased
this to 83%. These results are similar to those reported by Roilides
et al. (11), who used 4-day monocyte-derived macrophages and
a 2-h challenge with germinated conidia to estimate hyphal damage.
Here, we show that in 24-h combination studies, monocytes collaborated
with VCZ for significantly increased inhibition of hyphal growth,
from 58 to 79%. However, significantly increased inhibition
of hyphal growth by a combination of GM-CSF treatment of monocytes and
VCZ could not be demonstrated, possibly due to the already
high inhibitory activity of GM-CSF-treated monocytes.
| |
FOOTNOTES |
*
Corresponding author. Mailing address: Division of
Infectious Diseases, Department of Medicine, Santa Clara Valley Medical Center, 751 South Bascom Ave., San Jose, CA 95128-2699. Phone: (408)
885-4313. Fax: (408) 885-4306. E-mail:
stevens{at}leland.stanford.edu.
| |
REFERENCES |
| 1.
|
Brummer, E., and D. A. Stevens.
1996.
Synergy of human neutrophils with fluconazole in killing Candida species.
Mycopathologia
134:115-120[Medline].
|
| 2.
|
Denning, D. W.,
A. del Favero,
E. Gluckman,
D. Norfolk,
M. Ruhnke,
S. Yonren,
P. Troke, and N. Sarantis.
1996.
UK-109,496, a novel wide-spectrum triazole derivative for treatment of fungal infections: clinical efficacy in acute invasive aspergillosis, abstr. F80, p. 126.
In
Abstracts of the 36th Interscience Conference on Antimicrobial Agents and Chemotherapy. American Society for Microbiology, Washington, D.C.
|
| 3.
|
Denning, D. W.,
L. H. Hanson,
A. M. Perlman, and D. A. Stevens.
1992.
In vitro susceptibility and synergy studies of Aspergillus species to conventional and new agents.
Diagn. Microbiol. Infect. Dis.
15:21-34[Medline].
|
| 4.
|
Denning, D. W., and D. A. Stevens.
1990.
Antifungal and surgical treatment of invasive aspergillosis: review of 2,121 published cases.
Rev. Infect. Dis.
12:1147-1199[Medline].
|
| 5.
|
Garcha, U. K.,
E. Brummer, and D. A. Stevens.
1995.
Synergy of fluconazole with human monocytes or monocyte-derived macrophages for killing Candida species.
J. Infect. Dis.
172:1620-1623[Medline].
|
| 6.
|
Gujral, S.,
E. Brummer, and D. A. Stevens.
1996.
Role of extended culture time on synergy of fluconazole and human monocyte-derived macrophages in clearing Candida albicans.
J. Infect. Dis.
174:888-889[Medline].
|
| 7.
|
Hitchcock, C. A.,
G. E. Pye,
G. P. Oliver, and P. F. Troke.
1996.
UK-109,496, a novel wide-spectrum triazole derivative for the treatment of fungal infections: antifungal activity and selectivity in vitro, abstr. F72, p. 125.
In
Abstracts of the 36th Interscience Conference on Antimicrobial Agents and Chemotherapy. American Society for Microbiology, Washington, D.C.
|
| 8.
|
Levitz, S. M., and R. D. Diamond.
1985.
A rapid colorimetric assay for fungal viability with the tetrazolium salt MTT.
J. Infect. Dis.
152:938-945[Medline].
|
| 9.
|
Meshulam, T.,
S. M. Levitz,
L. Christin, and R. D. Diamond.
1995.
A simplified new assay for assessment of fungal cell damage with the tetrazolium dye (2,3)-bis-(2-methoxy-4-nitro-5-sulphenyl)-tetrazolium-5-carboxanilide (XTT).
J. Infect. Dis.
172:1153-1156[Medline].
|
| 10.
|
Oakley, K. L.,
C. B. Moore, and D. W. Denning.
1996.
In vitro activity of voriconazole against Aspergillus spp. and comparison with amphotericin B and itraconazole, abstr. F81, p. 114.
In
Abstracts of the 36th Interscience Conference on Antimicrobial Agents and Chemotherapy. American Society for Microbiology, Washington, D.C.
|
| 11.
|
Roilides, E.,
A. Holmes,
C. Blake,
D. Venzon,
P. A. Pizzo, and T. J. Walsh.
1994.
Antifungal activity of elutriated human monocytes against Aspergillus fumigatus hyphae: enhancement by granulocyte-macrophage colony-stimulating factor and interferon-gamma.
J. Infect. Dis.
170:894-899[Medline].
|
| 12.
|
Roilides, E.,
K. Uhlig,
D. Venzon,
P. A. Pizzo, and T. J. Walsh.
1993.
Enhancement of oxidative response and damage caused by human neutrophils to Aspergillus fumigatus hyphae by granulocyte colony-stimulating factor and gamma interferon.
Infect. Immun.
61:1185-1193[Abstract/Free Full Text].
|
Antimicrobial Agents and Chemotherapy, September 1998, p. 2299-2303, Vol. 42, No. 9
0066-4804/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
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[Full Text]
-
Patera, A. C., Menzel, F., Jackson, C., Brieland, J. K., Halpern, J., Hare, R., Cacciapuoti, A., Loebenberg, D.
(2004). Effect of Granulocyte Colony-Stimulating Factor Combination Therapy on Efficacy of Posaconazole (SCH56592) in an Inhalation Model of Murine Pulmonary Aspergillosis. Antimicrob. Agents Chemother.
48: 3154-3158
[Abstract]
[Full Text]
-
Van Epps, H. L., Feldmesser, M., Pamer, E. G.
(2003). Voriconazole Inhibits Fungal Growth without Impairing Antigen Presentation or T-Cell Activation. Antimicrob. Agents Chemother.
47: 1818-1823
[Abstract]
[Full Text]
-
Pearson, M. M, Rogers, P D., Cleary, J. D, Chapman, S. W
(2003). Voriconazole: A New Triazole Antifungal Agent. The Annals of Pharmacotherapy
37: 420-432
[Abstract]
[Full Text]
-
Gil-Lamaignere, C., Roilides, E., Maloukou, A., Georgopoulou, I., Petrikkos, G., Walsh, T. J.
(2002). Amphotericin B lipid complex exerts additive antifungal activity in combination with polymorphonuclear leucocytes against Scedosporium prolificans and Scedosporium apiospermum. J Antimicrob Chemother
50: 1027-1030
[Abstract]
[Full Text]
-
Gil-Lamaignere, C., Roilides, E., Mosquera, J., Maloukou, A., Walsh, T. J.
(2002). Antifungal Triazoles and Polymorphonuclear Leukocytes Synergize To Cause Increased Hyphal Damage to Scedosporium prolificans and Scedosporium apiospermum. Antimicrob. Agents Chemother.
46: 2234-2237
[Abstract]
[Full Text]
-
Roilides, E., Lyman, C. A., Filioti, J., Akpogheneta, O., Sein, T., Lamaignere, C. G., Petraitiene, R., Walsh, T. J.
(2002). Amphotericin B Formulations Exert Additive Antifungal Activity in Combination with Pulmonary Alveolar Macrophages and Polymorphonuclear Leukocytes against Aspergillus fumigatus. Antimicrob. Agents Chemother.
46: 1974-1976
[Abstract]
[Full Text]
-
Brummer, E., Maqbool, A., Stevens, D. A.
(2001). In vivo GM-CSF prevents dexamethasone suppression of killing of Aspergillus fumigatus conidia by bronchoalveolar macrophages. J. Leukoc. Biol.
70: 868-872
[Abstract]
[Full Text]
-
Chiller, T., Farrokhshad, K., Brummer, E., Stevens, D. A.
(2000). Influence of Human Sera on the In Vitro Activity of the Echinocandin Caspofungin (MK-0991) against Aspergillus fumigatus. Antimicrob. Agents Chemother.
44: 3302-3305
[Abstract]
[Full Text]
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Abstract
Introduction
