Previous Article | Next Article 
Applied and Environmental Microbiology, July 2000, p. 2817-2821, Vol. 66, No. 7
0099-2240/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Reduction of Pulmonary Toxicity of
Stachybotrys chartarum Spores by Methanol Extraction
of Mycotoxins
Carol Y.
Rao,*
Joseph
D.
Brain, and
Harriet A.
Burge
Department of Environmental Health, Harvard
School of Public Health, Boston, Massachusetts 02115
Received 20 December 1999/Accepted 11 April 2000
 |
ABSTRACT |
The fungus Stachybotrys chartarum has been implicated
in cases of nonspecific indoor air quality complaints in adults and in
cases of pulmonary hemorrhaging in infants. The effects that have been
described have been attributed to mycotoxins. Previous dose-effect
studies focused on exposure to a single mycotoxin in a solvent, a
strategy which is unlikely to accurately characterize the effects of
inhaled spores. In this study we examined the role of mycotoxins in the
pulmonary effects caused by S. chartarum spores and the
dose dependency of these effects. S. chartarum spores were
extracted in methanol to reduce the mycotoxin content of the spores.
Then either untreated (toxin-containing) or methanol-extracted S. chartarum spores were intratracheally instilled into male
10-week-old Charles River-Dawley rats. After 24 h, the lungs were
lavaged, and the bronchoalveolar lavage fluid was analyzed to determine differences in lactic dehydrogenase, albumin, hemoglobin,
myeloperoxidase, and leukocyte differential counts. Weight change was
also monitored. Our data show that methanol extraction dramatically
reduced the toxicity of S. chartarum spores. No
statistically significant effects were observed in the bronchoalveolar
lavage fluids of the animals that were treated with methanol-extracted
spores at any dose. Conversely, dose-dependent effects of the
toxin-containing spores were observed when we examined the lactic
dehydrogenase, albumin, and hemoglobin concentrations, the
polymorphonuclear leukocyte counts, and weight loss. Our findings show
that a single, intense exposure to toxin-containing S. chartarum spores results in pulmonary inflammation and injury in
a dose-dependent manner. Importantly, the effects are related to
methanol-soluble toxins in the spores.
| |
INTRODUCTION |
Acute exposure to Stachybotrys
chartarum spores results in severe pulmonary injury in animal
models (15, 16, 21). Although several outbreaks of illness
in humans have been attributed to respiratory exposure to S. chartarum, the causal link between fungal contamination in the
indoor environment and adverse pulmonary effects has yet to be firmly
established (4-6, 9, 13, 25).
The majority of the data regarding dose-response relationships between
mycotoxin exposure and health effects are 50% lethal dose data
resulting from ingestion or injection exposure in animals (10,
26). There are no data on the effects of low doses and the
effects of inhaled mycotoxins. One limiting factor in studies is the
ability to detect the pulmonary effects of low doses, since such doses
may not result in mortality or detectable histological changes. In
addition, S. chartarum can concurrently produce several different mycotoxins, each of which has different effects. These toxins
may act synergistically, and particle association may contribute to
toxicity (1, 2, 14, 23).
Bronchoalveolar lavage (BAL) has been used to detect adverse pulmonary
effects resulting from indoor exposure to fungi (17). The
indicators measured with BAL can be used to quantitatively evaluate pulmonary edema (albumin), cytotoxicity (lactic dehydrogenase [LDH]), polymorphonuclear leukocyte (PMN) activation (myeloperoxidase [MPO]), and pulmonary hemorrhaging (hemoglobin). Differential leukocyte enumerations for alveolar macrophages, PMNs, lymphocytes, and
eosinophils are used to assess cellular inflammatory and immunological responses. In the study described here, we used BAL to investigate the
dose-effect relationship between exposure to S. chartarum spores and pulmonary effects. To differentiate between
mycotoxin-induced injury and the effects of other fungal spore
components (e.g., allergens, 
-glucans), we also tested S. chartarum spores that had been extracted with methanol to reduce
the mycotoxin concentration in them.
| |
MATERIALS AND METHODS |
Fungal strains and spore suspensions.
Eight strains of
S. chartarum that were isolated from a Southern California
residence were screened for toxin production by using a modified brine
shrimp lethality assay as described by Eppley (8). A
toxin-producing strain was selected for the experiments. The strain of
S. chartarum used was maintained on potato dextrose agar
slants at 15°C. Spores were vacuumed from the surfaces of 14-day agar
cultures by using a modified filter cassette with a 37-mm-diameter,
0.4-µm-pore-size polycarbonate membrane filter (Poretics Corp.,
Livermore, Calif.). The spores were then suspended in 0.9% saline to
concentrations of 2 × 106, 4 × 106,
1 × 107, and 2 × 107 spores per ml.
A reduced-toxin S. chartarum spore suspension was prepared
from the same spore harvest by performing agitated extraction with
100% methanol (Sigma, Lenexa, Kans.) for 30 min. After centrifugation
at 350 × g for 10 min, the spore pellet was collected,
washed in fresh methanol, centrifuged, washed in saline, and then
suspended in fresh saline to concentrations of 2 × 106, 4 × 106, 1 × 107,
and 2 × 107 spores per ml. The concentrations and
nature of the spore suspensions were evaluated by light microscopy at a
magnification of ×200 in a hemocytometer chamber. Minor hyphal
fragments and negligible spore clumping were observed, and the majority
of the particles were ovoid spores with a mean size of 6.1 by 8.8 µm.
BAL procedures.
Male 10-week-old Charles River-Dawley rats
were supplied by Charles River Breeding Corporation. The average
initial weight of the animals was 332 ± 26.6 g. The rats
were housed in isolation at 25°C for at least a 1-week acclimation
period and were fed Purina Rat Chow and water ad libitum.
The spore suspensions were delivered into the lungs of the animals by
intratracheal instillation. The rats were anesthetized by inhalation of
5% halothane gas and then were placed on a slanted board. A freshly
prepared spore suspension or a saline carrier control was instilled
into the lungs of each animal with a 1-ml disposable tuberculin syringe
attached to a 3.5-in., 19-gauge, bent, blunt-tip needle inserted
between the vocal folds. Tracheal insertion was verified by detection
of the cartilaginous rings by the needle. The volume of the carrier
control (saline) or the spore suspension instilled was 150 µl per
100 g of body weight. The animal remained in the slanted position
until it recovered minimally, approximately 1 min. Then it was placed
on its back in a cage, where it regained consciousness within a few
minutes. After instillation, the animals were kept in the laboratory
under preinstillation housing and maintenance conditions.
After 24 h, the rats were reweighed, injected with 1 ml of sodium
pentobarbital, and then exsanguinated by cutting the abdominal
aorta.
The trachea was exposed and cannulated with an 18-gauge,
blunt-tip
needle fitted with a 1-in., flared, 19-gauge, polypropylene
tube and a
5-ml disposable syringe. The lungs were lavaged in
situ 12 times by
injecting 3 ml of phosphate-buffered saline into
them and then
massaging the ribcage while the lavage fluid was
aspirated. The first
two lavage aliquots were combined (approximately
5 ml) and centrifuged
under refrigerated conditions at 350 ×
g for 10 min.
The supernatant was reserved for use in LDH, MPO,
and albumin analyses.
The resulting cell pellet was combined with
the cell pellet obtained
from the next 10 lavage aliquots and
used for the cytospin and
hemoglobin
analyses.
Analysis of BAL fluid.
The total leukocyte count in the
lavage fluid was determined in a hemocytometer chamber at a
magnification of ×100. Leukocytes were identified on the basis of size
and granularity. After a cytospin (72 × g, 5 min)
onto a microscope slide, the deposited cells were fixed, stained, and
mounted in Permount. Differential counts for macrophages, PMNs,
eosinophils, and lymphocytes were determined at a magnification of
×200 by light microscopy.
The supernatant reserved from the first two lavage aliquots was
recentrifuged under refrigerated conditions at 14,500 ×
g for 30 min, and the resultant supernatant was analyzed to
determine
LDH, MPO, and albumin concentrations by spectrophotometry.
The
combined cell pellet obtained from all 12 lavage aliquots was
analyzed for hemoglobin. The supernatants of some of the lavage
aliquots from the animals that received the highest dose were
red
tinged (instead of clear). This indicated that some erythrocytes
had
been lysed; therefore, we may have underestimated the total
hemoglobin
concentration in some of the BAL samples by analyzing
only the cell
pellet. Biochemical analyses with a spectrophotometer
were performed as
described by Beck et al. (
3).
Statistical analyses.
Overall, 42 animals were instilled
with an untreated S. chartarum spore suspension
(SPORE animals), a methanol-extracted spore suspension
(XSPORE animals), or a carrier control (CONTROL
animals). For each instillate type, at least four animals were studied
with each instillate concentration (2 × 106, 4 × 106, 1 × 107, 2 × 107 spores/ml of instillate). All indicators
(concentrations of LDH, hemoglobin, albumin, and MPO; total number of
macrophages; total number of PMNs; total number of eosinophils; total
number of lymphocytes; and percent weight change) were examined for
each animal.
Statistical analyses were performed by using SAS statistical software
(
22). Analyses to determine the trends (SAS PROC MULTTEST)
for the BAL indicators and weight change were performed for each
instillate type (untreated
S. chartarum spores and
methanol-extracted
S. chartarum spores). If a trend was
significant for an indicator,
we used an analysis of variance (ANOVA)
with Dunnett's test (SAS
PROC GLM) to determine which responses to
doses were significantly
different from the carrier control animal
responses. Some of the
BAL indicators were transformed to obtain an
approximate Gaussian
distribution of the
residuals.
To determine if the BAL indicators for untreated spores and
methanol-extracted spores were different, we used an analysis
of
covariance (ANCOVA) to compare the BAL indicators for animals
instilled
with untreated
S. chartarum spores, animals instilled
with
methanol-extracted
S. chartarum spores, and animals
instilled
with the saline carrier control (SAS PROC GLM). We
constructed
a linear model in which the main effects were instillate
type,
dose, and the interaction of instillate type and dose. To account
for multiple comparisons, we examined only within-dose comparisons
between untreated
S. chartarum spores and methanol-extracted
S. chartarum spores when the F statistic for the interaction
effect
was significant. The differences between least-square means
derived
from the model were used to determine statistical significance.
The critical value used was
P < 0.05.
| |
RESULTS |
Methanol-extracted S. chartarum spores.
No linear
trends were observed for most of the BAL indicators or for weight
change for animals instilled with methanol-extracted spores
(XSPORE animals); the only exception was MPO
(P = 0.02 [data not shown]). Within the data
set, 70% of the MPO measurements were below the limit of detection,
resulting in small variances which may explain the apparent
positive trend. The LDH (Fig. 1), hemoglobin (Fig. 2), and albumin (Fig.
3) concentrations; the macrophage, PMN,
lymphocyte, and eosinophil counts (Fig.
4); and the weight change percentages for
the XSPORE animals (Fig.
5) were not significantly different than
the values obtained for the CONTROL animals at the experimental doses
used.
View larger version (19K):
[in this window]
[in a new window]
|
FIG. 1.
Mean concentrations of LDH in BAL fluid 24 h after
S. chartarum spore instillation. The error bars indicate
standard errors. A plus sign indicates that a P value is
<0.05 for within-dose comparisons between animals instilled with
untreated S. chartarum spores (SPORE) and animals
instilled with methanol-extracted S. chartarum spores
(XSPORE), with the caveat that the
multiple-comparison F statistic of the ANCOVA is borderline significant
(P = 0.12).
|
|
View larger version (18K):
[in this window]
[in a new window]
|
FIG. 2.
Mean concentrations of hemoglobin in BAL fluid 24 h
after S. chartarum spore instillation. The error bars
indicate standard errors. A plus sign indicates that the P
value is <0.05 for within-dose comparisons between animals instilled
with untreated S. chartarum spores (SPORE) and
animals instilled with methanol-extracted S. chartarum
spores (XSPORE), with the caveat that the
multiple-comparison F statistic of the ANCOVA is borderline significant
(P = 0.18).
|
|
View larger version (18K):
[in this window]
[in a new window]
|
FIG. 3.
Mean concentrations of albumin in BAL fluid 24 h
after S. chartarum spore instillation. The error bars
indicate standard errors. Animals instilled with untreated S. chartarum spores (SPORE) were compared to animals
instilled with methanol-extracted S. chartarum spores
(XSPORE). An asterisk indicates that the
P value is <0.05.
|
|
View larger version (29K):
[in this window]
[in a new window]
|
FIG. 4.
Mean macrophage (a), PMN (b), lymphocyte (c), and
eosinophil (d) counts in BAL fluid 24 h after S. chartarum spore instillation. The error bars indicate standard
errors. A plus sign indicates that the P value is <0.05 for
within-dose comparisons between animals instilled with untreated
S. chartarum spores (SPORE) and animals instilled
with methanol-extracted spores (XSPORE) with the
caveat that the multiple-comparison ANCOVA F statistic for total PMN
counts is borderline significant (P = 0.09).
|
|
View larger version (21K):
[in this window]
[in a new window]
|
FIG. 5.
Mean percent weight change 24 h after instillation.
The error bars indicate standard errors. Animals instilled with
untreated S. chartarum spores (SPORE) were
compared to animals instilled with methanol-extracted S. chartarum spores (XSPORE). An asterisk
indicates that the P value is <0.05.
|
|
Untreated S. chartarum spores. (i) Physiological
effects: weight change.
As the untreated S. chartarum spore instillate concentration increased
(SPORE animals), the animals lost more weight (P = 0.0001) (Fig. 5). There were significant differences compared to
the weights of the CONTROL (Table 1) and
XSPORE (Fig. 5) animals at the two highest
instillate concentrations.
View this table:
[in this window]
[in a new window]
|
TABLE 1.
P values from an ANOVA model comparison:
animals instilled with untreated S. chartarum spores
(SPORE animals) versus animals treated with a saline
carrier (CONTROL animals)a
|
|
(ii) Pulmonary injury and inflammation.
The LDH (P = 0.003) and hemoglobin (P = 0.005) concentrations
increased linearly as the untreated S. chartarum spore
instillate concentration increased (Fig. 1 and 2, respectively).
Compared to the values for the CONTROL animals, the concentrations of
LDH in the BAL fluid were significantly different at the two highest doses and the concentration of hemoglobin was significantly different at the highest instillate dose (Table 1). When the SPORE and XSPORE animal instillates were compared, the
hemoglobin or LDH concentrations in the BAL fluid were not
significantly different (P = 0.18 and P = 0.12, respectively). However, with the caveat that the
multiple-comparison F statistics were not significant, the
within-dose differences between the SPORE and
XSPORE animals exhibited the same pattern that the
SPORE and CONTROL animal differences exhibited (Table 1).
The albumin concentration (Fig.
3) and the total PMN count (Fig.
4b)
increased significantly as the SPORE dose increased
(
P = 0.0001 for both indicators). Linear trends were
not observed
with the MPO concentration or with the other leukocyte
counts
(macrophages, lymphocytes, and eosinophils). The albumin
concentrations
and the total PMN counts in the BAL fluid from
SPORE animals were
significantly different from the values
for the CONTROL animals
(Table
1) and the XSPORE
animals at instillate concentrations
equal to or greater than 4 × 10
6 spores/ml.
| |
DISCUSSION |
Mycotoxin-specific effects.
In vitro studies have shown that
nontoxic, noninfective species of fungi can modulate production of
cytokines and reactive oxygen species, which in turn can elicit
pulmonary inflammation (19, 24). Mycotoxins are highly
soluble in organic solvents and slightly soluble in physiological
fluids (11, 18). We extracted S. chartarum spores
in methanol to reduce their mycotoxin content. The pulmonary responses
of animals instilled with methanol-extracted spores were similar to the
pulmonary responses of CONTROL animals and significantly less than the
pulmonary responses of animals instilled with untreated S. chartarum spores. The lack of a linear trend for any of the
indicators measured (except MPO) in animals treated with
methanol-extracted spores demonstrated that the methanol-extractable fraction played a significant role in pulmonary inflammation.
Some glucans, extracellular polysaccharides, lipids, and allergens,
which can also cause inflammation, may also have been
extracted or
altered by the methanol. In addition, the methanol
treatment sterilized
the spores. Thus, the lack of effects associated
with the
methanol-extracted
S. chartarum spores cannot be attributed
solely to the absence of mycotoxins. However, previous research
in our
laboratory has shown that non-mycotoxin-containing fungal
spores (i.e.,
Penicillium chrysogenum and
Cladosporium
sphaerospermum)
have dose-effect relationships for the BAL
indicators similar
to the dose-effect relationships of the
methanol-extracted
S. chartarum spores (J. D. Brain, T. Donaghey, C. Y. Rao, and H.
A. Burge, unpublished data). They
are also less toxic than nonextracted
S. chartarum spores.
Moreover,
S. chartarum spores that exhibit
low toxicity (as
measured by cell culture assays) have also been
shown to have
diminished effects on pulmonary tissue (
16).
Dose-related toxic effects of untreated S. chartarum
spores. (i) Physiological effects.
Overt physiological effects of
acute pulmonary exposure to S. chartarum were reflected by
dose-dependent decreases in body weight. Within 24 h after
instillation of untreated spores, the animals that received the highest
doses lost up to 13% of their body weight, while CONTROL animals
generally remained the same weight. The acute weight loss suggests that
consumption of food and water decreased, which could have resulted from
general malaise related to local effects or from systemic toxicity. In
some human case studies, systemic effects such as malaise, flulike
symptoms, muscle aches, and headaches have been associated with
postulated airborne exposure to S. chartarum spores (6,
7, 12, 13).
(ii) Pulmonary injury and inflammation.
The increased levels
of LDH, hemoglobin, albumin, and PMNs in the BAL fluid reflect the
direct effects of S. chartarum spores and their constituents
on lung tissue. In normal lungs, extracellular LDH (resulting from
cytotoxicity and cell death) and hemoglobin (resulting from erythrocyte
infiltration through capillary bed perforations) are not detectable in
the lavage fluid. Both of these indicators are sensitive indicators of
localized injury, a likely result if a large number of spores were
deposited in a relatively small area of tissue. This effect was
demonstrated by the significant changes in LDH and hemoglobin
concentrations that were observed at the higher doses. Mucosal
hemorrhaging and tissue necroses have been observed in animals that
have ingested large amounts of S. chartarum-contaminated
fodder (12, 20). Although trichothecenes are potent
inhibitors of protein synthesis, the specific mechanisms of action that
result in localized injury are not known.
An increase in the level of albumin, a serum protein that is
abundant in BAL fluid, may be an early and sensitive indicator
of
widespread inflammation. Significant differences from CONTROL
animals were apparent at lower spore instillate concentrations
for
albumin than for LDH and hemoglobin. Moreover, significant
increases in
albumin concentrations were observed as soon as 6
h after
pulmonary exposure to
S. chartarum spores (C. Y. Rao,
H. A. Burge, and J. D. Brain, unpublished
data).
The total leukocyte counts in BAL fluid increased, and PMNs were the
major contributor to this increase. Total macrophages,
lymphocytes, and
eosinophils did not increase as the instillate
concentration
increased. One day may not be long enough for such
changes to occur. We
have observed significant increases in macrophage
counts 72 h
after instillation (Rao et al., unpublished
data).
It has been hypothesized that the presence of
S. chartarum
in occupied spaces is responsible for building-related adverse
health
effects, including pulmonary hemorrhaging. Mycotoxins in
the spores are
the presumed causative factor. Documenting such
effects requires
demonstrating that (i)
S. chartarum spores in
the
environment contained toxins; (ii) the observed effect is
related to
the toxin content rather than to other spore components
or other
nonfungal factors; and (iii) sufficient toxin exposure
occurs to
achieve a toxic dose. We provide evidence that there
is a dose-related
association between an acute exposure to toxin-containing
S. chartarum spores and measurable pulmonary responses. The
consequences
of low-level chronic exposure remain to be investigated,
as does
the relevance of the rodent data to human
exposure.
| |
ACKNOWLEDGMENTS |
This work was supported by grant HL07118 from the National Heart,
Lung and Blood Institute.
We thank Donald Milton for statistical advice, Tom Donaghey for
technical guidance, and Janet Gallup for providing the S. chartarum isolates.
| |
FOOTNOTES |
*
Corresponding author. Present address: NIOSH, 1095 Willowdale Road, Morgantown, WV 26505. Phone: (304) 285-5987. Fax:
(304) 285-5820. E-mail: cnr3{at}cdc.gov.
| |
REFERENCES |
| 1.
|
Andersson, M. A.,
M. Nikulin,
U. Koljalg,
M. C. Andersson,
F. Rainey,
K. Reijula,
E. L. Hintikka, and M. Salkinoja-Salonen.
1997.
Bacteria, molds, and toxins in water-damaged building materials.
Appl. Environ. Microbiol.
63:387-393[Abstract/Free Full Text].
|
| 2.
|
Andriendko, E., and A. Zaichenko.
1997.
Certain peculiarities of biological action of the stachybotryotoxin preparations.
Mikrobiol. Zh.
59:41-46.
|
| 3.
|
Beck, B. D.,
J. D. Brain, and D. E. Bohannon.
1982.
An in vivo hamster bioassay to assess the toxicity of particulates for the lungs.
Toxicol. Appl. Pharmacol.
66:9-29[CrossRef][Medline].
|
| 4.
|
Centers for Disease Control and Prevention.
1997.
Update: pulmonary hemorrhage/hemosiderosis among infants Cleveland, Ohio, 1993-1996.
Morbid. Mortal. Weekly Rep.
46(2):33-35[Medline].
|
| 5.
|
Cooley, J.,
W. Wong,
C. Jumper, and D. Straus.
1998.
Correlation between the prevalence of certain fungi and sick building syndrome.
Occup. Environ. Med.
55:579-584[Abstract/Free Full Text].
|
| 6.
|
Croft, W. A.,
B. B. Jarvis, and C. S. Yatawara.
1986.
Airborne outbreak of trichothecene toxicosis.
Atmos. Environ.
20:549-552[CrossRef].
|
| 7.
|
Elidemir, O.,
G. N. Colasurdo,
S. N. Rossmann, and L. Fan.
1999.
Isolation of Stachybotrys from the lung of a child with pulmonary hemosiderosis.
Pediatrics
104:964-966[Abstract/Free Full Text].
|
| 8.
|
Eppley, R. M.
1974.
Sensitivity of brine shrimp (Artemia salina) to trichothecenes.
J. Assoc. Off. Anal. Chem.
57:618-620[Medline].
|
| 9.
|
Fung, F.,
R. Clark, and S. Williams.
1998.
Stachybotrys, a mycotoxin-producing fungus of increasing importance.
J. Toxicol. Clin. Toxicol.
36:629-631[Medline].
|
| 10.
|
Glavits, R.
1988.
Effect of trichothecene mycotoxins (satratoxin H and T-2 toxin) on the lymphoid organs of mice.
Acta Vet. Hung.
36:37-41[Medline].
|
| 11.
|
Harrach, B.,
M. Nummi,
M. L. Niku-Paavola,
C. J. Mirocha, and M. Palyusik.
1982.
Identification of "water-soluble" toxins produced by a Stachybotrys atra strain from Finland.
Appl. Environ. Microbiol.
44:494-495[Abstract/Free Full Text].
|
| 12.
|
Hintikka, E.-L.
1978.
Human stachybotryotoxicosis, p. 87-89.
In
T. Wyllie, and L. Morehouse (ed.), Mycotoxic fungi, mycotoxins and mycotoxicosis, vol. 3. Marcel Dekker, New York, N.Y.
|
| 13.
|
Johanning, E.,
R. Biagini,
D. Hull,
P. Morey,
B. Jarvis, and P. Landsbergis.
1996.
Health and immunology study following exposure to toxigenic fungi (Stachybotrys chartarum) in a water-damaged office environment.
Int. Arch. Occup. Environ. Health
68:207-218[Medline].
|
| 14.
|
Koshinsky, H., and G. Khachatourians.
1992.
Trichothecene synergism, additivity, and antagonism: the significance of the maximally quiescent ratio.
Nat. Toxins
1:38-47[CrossRef][Medline].
|
| 15.
|
Nikulin, M.,
K. Reijula,
B. B. Jarvis, and E. L. Hintikka.
1996.
Experimental lung mycotoxicosis in mice induced by Stachybotrys atra.
Int. J. Exp. Pathol.
77:213-218[CrossRef][Medline].
|
| 16.
|
Nikulin, M.,
K. Reijula,
B. B. Jarvis,
P. Veijalainen, and E. L. Hintikka.
1997.
Effects of intranasal exposure to spores of Stachybotrys atra in mice.
Fundam. Appl. Toxicol.
35:182-188[CrossRef][Medline].
|
| 17.
|
Park, H.,
K. Jung,
S. Kim, and S. Kim.
1994.
Hypersensitivity pneumonitis induced by Penicillium expansum in a home environment.
Clin. Exp. Allergy
24:383-385[CrossRef][Medline].
|
| 18.
|
Pasanen, A.,
J. Nikulin,
M. Tuimainen,
S. Berg,
P. Parikka, and E.-L. Hintikka.
1993.
Laboratory experiments on membrane filter sampling of airborne mycotoxins produced by Stachybotrys atra Corda.
Atmos. Environ.
27A:9-13.
|
| 19.
|
Ruotsalainen, M.,
A. Hyvarinen,
A. Nevalainen, and K. M. Savolainen.
1995.
Production of reactive oxygen metabolites by opsonized fungi and bacteria isolated from indoor air, and their interactions with soluble stimuli, fMLP or PMA.
Environ. Res.
69:122-131[Medline].
|
| 20.
|
Samsonov, P.
1960.
Respiratory mycotoxicoses (pneumonomycotoxicoses), p. 131-139.
In
V. Bilay (ed.), Mycotoxicosis of man and agricultural animals. U.S. Joint Publications Research Service, Washington, D.C.
|
| 21.
|
Samsonov, P., and A. Samsonov.
1960.
The respiratory mycotoxicoses (pneumonomycotoxicoses) experimentally, p. 140-150.
In
V. Bilay (ed.), Mycotoxicosis of man and agricultural animals. U.S. Joint Publications Research Service, Washington, D.C.
|
| 22.
|
SAS Institute.
1996.
SAS/STAT software, 6.12 ed.
SAS Institute Inc., Cary, N.C.
|
| 23.
|
Schiefer, H.,
D. Hancock, and A. Bhatti.
1986.
Systemic effects of topically applied trichothecenes. I. Comparative study of various trichothecenes in mice.
J. Vet. Med. Ser. A
33:373-383.
|
| 24.
|
Shahan, T.,
W. Sorenson, and D. Lewis.
1994.
Superoxide anion production in response to bacterial lipopolysaccharide and fungal spores implicated in organic dust toxic syndrome.
Environ. Res.
67:98-107[Medline].
|
| 25.
|
Sudakin, D.
1998.
Toxigenic fungi in a water-damaged building: an intervention study.
Am. J. Ind. Med.
34:183-190[CrossRef][Medline].
|
| 26.
|
Yoshizawa, T.,
K. Ohtsubo,
T. Sasaki, and K. Nakamura.
1986.
Acute toxicities of satratoxins G and H in micea histopathological observation with special reference to the liver injury caused by satratoxin G.
Proc. Jpn. Assoc. Mycotoxicol.
23:53-57.
|
Applied and Environmental Microbiology, July 2000, p. 2817-2821, Vol. 66, No. 7
0099-2240/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Pestka, J. J., Yike, I., Dearborn, D. G., Ward, M. D. W., Harkema, J. R.
(2008). Stachybotrys chartarum, Trichothecene Mycotoxins, and Damp Building-Related Illness: New Insights into a Public Health Enigma. Toxicol Sci
104: 4-26
[Abstract]
[Full Text]
-
Yike, I., Rand, T. G., Dearborn, D. G.
(2005). Acute Inflammatory Responses to Stachybotrys chartarum in the Lungs of Infant Rats: Time Course and Possible Mechanisms. Toxicol Sci
84: 408-417
[Abstract]
[Full Text]
-
Flemming, J., Hudson, B., Rand, T. G.
(2004). Comparison of Inflammatory and Cytotoxic Lung Responses in Mice after Intratracheal Exposure to Spores of Two Different Stachybotrys chartarum Strains. Toxicol Sci
78: 267-275
[Abstract]
[Full Text]
-
Dearborn, D. G., Smith, P. G., Dahms, B. B., Allan, T. M., Sorenson, W.G., Montana, E., Etzel, R. A.
(2002). Clinical Profile of 30 Infants With Acute Pulmonary Hemorrhage in Cleveland. Pediatrics
110: 627-637
[Abstract]
[Full Text]
-
Rand, T. G., Mahoney, M., White, K., Oulton, M.
(2002). Microanatomical Changes in Alveolar Type II Cells in Juvenile Mice Intratracheally Exposed to Stachybotrys chartarum Spores and Toxin. Toxicol Sci
65: 239-245
[Abstract]
[Full Text]
-
Kordula, T., Banbula, A., Macomson, J., Travis, J.
(2002). Isolation and Properties of Stachyrase A, a Chymotrypsin-Like Serine Proteinase from Stachybotrys chartarum. Infect. Immun.
70: 419-421
[Abstract]
[Full Text]
Top
Abstract
Introduction
