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Biomedical subjects

D C Straus

Publications and source records attributed to D C Straus.

At least 19 recordsLinked to original sources
PubMed2005

Detection of airborne Stachybotrys chartarum macrocyclic trichothecene mycotoxins on particulates smaller than conidia.

Highly respirable particles (diameter, <1 microm) constitute the majority of particulate matter found in indoor air. It is hypothesized that these particles serve as carriers for toxic compounds, specifically the compounds produced by molds in water-damaged buildings. The presence of airborne Stachybotrys chartarum trichothecene mycotoxins on particles smaller than conidia (e.g., fungal fragments) was therefore investigated. Cellulose ceiling tiles with confluent Stachybotrys growth were placed in gas-drying containers through which filtered air was passed. Exiting particulates were collected by using a series of polycarbonate membrane filters with decreasing pore sizes. Scanning electron microscopy was employed to determine the presence of conidia on the filters. A competitive enzyme-linked immunosorbent assay (ELISA) specific for macrocyclic trichothecenes was used to analyze filter extracts. Cross-reactivity to various mycotoxins was examined to confirm the specificity. Statistically significant (P < 0.05) ELISA binding was observed primarily for macrocyclic trichothecenes at concentrations of 50 and 5 ng/ml and 500 pg/ml (58.4 to 83.5% inhibition). Of the remaining toxins tested, only verrucarol and diacetylverrucarol (nonmacrocyclic trichothecenes) demonstrated significant binding (18.2 and 51.7% inhibition, respectively) and then only at high concentrations. The results showed that extracts from conidium-free filters demonstrated statistically significant (P < 0.05) antibody binding that increased with sampling time (38.4 to 71.9% inhibition, representing a range of 0.5 to 4.0 ng/ml). High-performance liquid chromatography analysis suggested the presence of satratoxin H in conidium-free filter extracts. These data show that S. chartarum trichothecene mycotoxins can become airborne in association with intact conidia or smaller particles. These findings may have important implications for indoor air quality assessment.

Air Microbiology↗
PubMed2005

Detection of airborne Stachybotrys chartarum macrocyclic trichothecene mycotoxins in the indoor environment.

The existence of airborne mycotoxins in mold-contaminated buildings has long been hypothesized to be a potential occupant health risk. However, little work has been done to demonstrate the presence of these compounds in such environments. The presence of airborne macrocyclic trichothecene mycotoxins in indoor environments with known Stachybotrys chartarum contamination was therefore investigated. In seven buildings, air was collected using a high-volume liquid impaction bioaerosol sampler (SpinCon PAS 450-10) under static or disturbed conditions. An additional building was sampled using an Andersen GPS-1 PUF sampler modified to separate and collect particulates smaller than conidia. Four control buildings (i.e., no detectable S. chartarum growth or history of water damage) and outdoor air were also tested. Samples were analyzed using a macrocyclic trichothecene-specific enzyme-linked immunosorbent assay (ELISA). ELISA specificity was tested using phosphate-buffered saline extracts of the fungal genera Aspergillus, Chaetomium, Cladosporium, Fusarium, Memnoniella, Penicillium, Rhizopus, and Trichoderma, five Stachybotrys strains, and the indoor air allergens Can f 1, Der p 1, and Fel d 1. For test buildings, the results showed that detectable toxin concentrations increased with the sampling time and short periods of air disturbance. Trichothecene values ranged from <10 to >1,300 pg/m3 of sampled air. The control environments demonstrated statistically significantly (P < 0.001) lower levels of airborne trichothecenes. ELISA specificity experiments demonstrated a high specificity for the trichothecene-producing strain of S. chartarum. Our data indicate that airborne macrocyclic trichothecenes can exist in Stachybotrys-contaminated buildings, and this should be taken into consideration in future indoor air quality investigations.

Air Microbiology↗
PubMed2005

Effect of chlorine dioxide gas on fungi and mycotoxins associated with sick building syndrome.

The growth of indoor molds and their resulting products (e.g., spores and mycotoxins) can present health hazards for human beings. The efficacy of chlorine dioxide gas as a fumigation treatment for inactivating sick building syndrome-related fungi and their mycotoxins was evaluated. Filter papers (15 per organism) featuring growth of Stachybotrys chartarum, Chaetomium globosum, Penicillium chrysogenum, and Cladosporium cladosporioides were placed in gas chambers containing chlorine dioxide gas at either 500 or 1,000 ppm for 24 h. C. globosum was exposed to the gas both as colonies and as ascospores without asci and perithecia. After treatment, all organisms were tested for colony growth using an agar plating technique. Colonies of S. chartarum were also tested for toxicity using a yeast toxicity assay with a high specificity for trichothecene mycotoxins. Results showed that chlorine dioxide gas at both concentrations completely inactivated all organisms except for C. globosum colonies which were inactivated an average of 89%. More than 99% of ascospores of C. globosum were nonculturable. For all ascospore counts, mean test readings were lower than the controls (P < 0.001), indicating that some ascospores may also have been destroyed. Colonies of S. chartarum were still toxic after treatment. These data show that chlorine dioxide gas can be effective to a degree as a fumigant for the inactivation of certain fungal colonies, that the perithecia of C. globosum can play a slightly protective role for the ascospores and that S. chartarum, while affected by the fumigation treatment, still remains toxic.

Chaetomium↗
PubMed2004

Children symptoms before and after knowing about an indoor fungal contamination.

To describe children symptoms before and after an indoor fungal problem was publicized. Children attending one of two elementary schools (one with indoor fungal problems and one without) were included in this study. The study included an analysis of symptoms reported by the nurses before and after the indoor fungal problem was publicized and a questionnaire responded to by the parents. Several symptoms related to exposure to mold were found to be statistically significant in the school with an indoor fungal problem before the problem was detected: the symptoms included coughing/wheezing, headaches and joint pains. After the problem was publicized the perception of symptoms increased.

Air Pollution, Indoor↗
PubMed2004

An investigation into techniques for cleaning mold-contaminated home contents.

This study examined the efficacy of the following treatments to reduce selected fungal spore and mycotoxin levels on materials commonly found in home contents: (1) gamma irradiation at a 10-13 kiloGray exposure, (2) a detergent/bleach wash, and (3) a steam cleaning technique. A minimum of six replicates were performed per treatment. Paper, cloth, wood, and carpet were inoculated with either fungal spores (Stachybotrys chartarum, Aspergillus niger, Penicillium chrysogenum, or Chaetomium globosum) at 240,000 spores/2.54 cm2 of material or with the mycotoxins roridin A, T-2, and verrucarin A at 10 microg per 2.54 cm2 of material. Treatments were evaluated with an agar plating technique for fungal spores and a yeast toxicity culture assay for mycotoxins. Results showed that gamma irradiation inactivated fungal spores, but the treatment was not successful in inactivating mycotoxins. The washing technique completely inactivated or removed spores on all materials except for C. globosum, which was reduced on all items except paper (p < 0.05). Washing inactivated all mycotoxins on paper and cloth but not on carpet or untreated wood (p < 0.001). The steam cleaning treatment did not completely eliminate any fungal spores; however, it reduced P. chrysogenum numbers on all materials, C. globosum was reduced on wood and carpet, and S. chartarum was reduced on wood (p < 0.05). Steam cleaning was unsuccessful in inactivating any of the tested mycotoxins. These results show that the bleach/detergent washing technique was more effective overall in reducing spore and mycotoxin levels than gamma irradiation or steam cleaning. However, the other examined techniques were successful in varying degrees.

Chlorine↗
PubMed2004

Allergic inflammation induced by a Penicillium chrysogenum conidia-associated allergen extract in a murine model.

BACKGROUND: Recent evidence has shown that viable conidia from the fungus Penicillium chrysogenum induce allergic effects in mice. The present study was conducted to determine the specific allergic dose response of C57BL/6 mice to the protease extract, Pen ch, isolated from viable P. chrysogenum conidia. METHODS: Mice were treated with primary intraperitoneal (IP) injections of 10 or 100 microg of Pen ch adsorbed to alum, followed by weekly IP injections of 0.1, 1.0, or 10.0 microg Pen ch with alum for 4 weeks, and with 10.0 microg of Pen ch by intranasal (IN) inoculations the final 2 weeks before killing. RESULTS: Intraperitoneal injections of 10 and 100 microg of Pen ch for 5 weeks followed by 2 weeks of IN instillation of 10 microg induced significant increases of total serum immunoglobulin (Ig)E and IgG(1). Bronchoalveolar lavage cell counts revealed increased numbers of eosinophils and neutrophils. Histopathological examination of lungs detected perivascular inflammation by eosinophils and neutrophils and increased mucous production. CONCLUSIONS: The data presented in this study indicate that sensitization to protease allergens released by viable P. chrysogenum conidia in vivo induce a strong allergic inflammatory response in a murine model, which could have implications for people exposed to high levels of conidia of this organism.

Administration, Intranasal↗
PubMed2002

Airborne microbial flora in a cattle feedlot.

A total of 1,408 cattle held in eight commercial feedlot pens were used to examine the quantity and diversity of microorganisms in cattle feedlot air. The effect of two feeding patterns on the generation of airborne dust and the total numbers of microorganisms was also examined (four feedlot pens/treatment). Microbial samples were collected, and dust particles that were 2.5 microm or less in diameter were measured with a Dustrak monitor during the evening dust peak for 4 days at sites both upwind and downwind of the feedlot pens. An Andersen biological cascade sampler was employed with different medium and incubation combinations for the capture and identification of bacteria and fungi. The results showed that when bacteria were considered, only nonpathogenic gram-positive organisms were recovered. However, gram-negative bacteria may have been present in a viable but nonculturable state. Fungi were recovered in smaller numbers than bacteria, and none of the fungi were pathogenic. The Dustrak results showed that one feeding pattern resulted in cattle behavior that generated levels of downwind dust lower (P = 0.04) than the levels generated by the behavior resulting from the other feeding pattern. However, the Andersen sampler results showed that there were no differences between feeding patterns with regard to the total number or diversity of microorganisms. The disparity may have been due to the different operating principles of the two systems. The overall numbers of microorganisms recovered were lower than those reported in studies of intensively housed farm animals in which similar recovery techniques were used.

Air Microbiology↗
PubMed2002

The presence of fungi associated with sick building syndrome in North American zoological institutions.

A total of 110 sites from five zoological institutions were examined to determine whether fungi associated with sick building syndrome (SBS) were prevalent in the exhibits or night-time holding facilities and to investigate whether the presence of these organisms was associated with declining breeding rates or increases in morbidity and mortality (or both). Each site was sampled with an Andersen two-stage air sampler using Sabourauds dextrose agar media and a Burkard personal volumetric air sampler. Suspect surfaces were also sampled. High levels of airborne Penicillium chrysogenum, a fungal species associated with poor indoor air quality, were recovered from 16 sites out of all five institutions. Five culturable growth sites of Stachybotrys chartarum, a species strongly associated with SBS and commonly known as "black mold," were recovered from surfaces at two institutions. A wide range of other fungal species was recovered in low numbers from all institutions. A Fisher exact test analysis showed a significant nonrandom association between high levels of P. chrysogenum and sites with records of poor animal health. This study indicated that significant numbers of airborne fungi associated with SBS and poor indoor air quality are present in zoological institutions and that they could affect animal health and reproduction rates and zoo staff.

Air Microbiology↗
PubMed2001

Evaluation of fungal growth on cellulose-containing and inorganic ceiling tile.

Buildings with poor indoor air quality (IAQ) frequently have many areas with surface fungal contamination. Studies have demonstrated that certain fungal genera (e.g., Cladosporium, Penicillium, and Stachybotrys) are able to grow on building materials such as wallpaper, drywall, and ceiling tiles, particularly after water damage has occurred. Due to the increasing awareness of sick building syndrome (SBS), it has become essential to identify building materials that prevent the interior growth of fungi. The objective of this study was to identify building materials that would not support the growth of certain fungal genera, regardless of whether an external food source was made available. The growth of three fungal genera (Cladosporium, Penicillium, and Stachybotrys) was evaluated on cellulose-containing ceiling tile (CCT) and inorganic ceiling tile (ICT). Both types of ceiling tile were exposed to environmental conditions which can occur inside a building. Our results show that ICT did not support the growth of these three fungal genera while CCT did. Our data demonstrate that ICT could serve as an ideal replacement for CCT.

Cellulose↗
PubMed2001

Water quality in cattle feedyard playas in winter and summer.

OBJECTIVE: To determine the impact of feedyards on endotoxin concentration, fecal coliform count, and other water quality measurements during winter and summer in feedyard playas (shallow lakes). SAMPLE POPULATION: Water samples obtained from 7 feedyard playas and 3 nonfeedyard control playas. PROCEDURE: Surface water samples were collected from each playa and at various depths from 3 feedyard playas. Endotoxin concentrations, 22 water quality variables, and fecal coliform counts were determined in samples collected in summer and winter from various combinations of playas. RESULTS: Cattle numbers per feedyard ranged from 40,000 to 175,000 head/y. Mean endotoxin concentrations were significantly lower in control playas than in feedyard playas in winter and summer. Endotoxin concentration appeared to be homogenous at various water depths. Values for 20 of 22 water quality variables were higher in the feedyard playas than in control playas in winter and summer. In winter only, mean total fecal coliform concentration in feedyard playas was significantly greater than in control playas. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that feedyards have the potential to impact water quality in playas, and cattle should not be allowed access to them. Feedyard playa water should not be used under high pressure to settle dust in pens with cattle or to cool cattle, because aerosols containing pathogens and high concentrations of endotoxin are a health hazard for humans and cattle?

Animals↗
PubMed2000

Lipase activity from strains of Pasteurella multocida.

Thirteen clinical isolates of Pasteurella multocida from a variety of different animals and humans were examined for their ability to produce lipase. Lipase substrates used included Tween 20, Tween 40, Tween 80, and Tween 85. Lipase activity was detected in the filtrates of organisms grown to the exponential phase in Roswell Park Memorial Institute-1640 defined media (RPMI-1640), but activity increased in the filtrates when the cultures were allowed to proceed to the stationary phase. All strains examined (except for serotype 2) showed lipase activity against at least one of the Tweens. Tween 40 was the best substrate to demonstrate lipase activity. Pasteurella multocida serotype 8 produced the most active lipase against Tween 40 (3,561.7 units of activity/microgram of protein). This activity continued to increase after P. multocida entered a stationary growth phase. P. multocida lipase activity was optimal at pH 8.0. Lipase activity of P. multocida serotype 8 was eluted from a Sepharose 2B column at several points, indicating that several lipases may be produced in vitro by this organism. These data demonstrate that clinical isolates of P. multocida produce lipase; therefore, this enzyme should be considered a potential virulence factors for this organism.

Animals↗
PubMed2000

An animal model for allergic penicilliosis induced by the intranasal instillation of viable Penicillium chrysogenum conidia.

BACKGROUND: A study was undertaken to determine the consequences of long term intranasal instillation of Penicillium chrysogenum propagules in a mouse model. METHODS: C57 Black/6 mice were inoculated intranasally each week for six weeks with 10(4) viable and non-viable P chrysogenum conidia. Cytokine levels and cellular responses in these animals were then measured. RESULTS: Compared with controls, mice inoculated intranasally each week for six weeks with 10(4) P chrysogenum conidia (average viability 25%) produced significantly more total serum IgE (mean difference 1823.11, lower and upper 95% confidence intervals (CI) 539.09 to 3107.13), peripheral eosinophils (mean difference 5.11, 95% CI 2.24 to 7.99), and airway eosinophilia (rank difference 11.33, 95% CI 9.0 to 20.0). With the exception of airway neutrophilia (mean difference 20.89, 95% CI 3.72 to 38.06), mice inoculated intranasally with 10(4) non-viable conidia did not show significant changes in total serum IgE, peripheral or airway eosinophils. However, when compared with controls, this group (10(4) non-viable) had a significant increase in total serum IgG(2a) (mean difference 1990.56, 95% CI 790.48 to 3190.63) and bronchoalveolar lavage (BAL) fluid levels of interferon (IFN)-gamma (mean difference 274.72, 95% CI 245.26 to 304.19). In addition, lung lavages from mice inoculated intranasally with 10(4) viable P chrysogenum conidia had significantly increased levels of interleukin (IL)-4 (mean difference 285.28, 95% CI 108.73 to 461.82) and IL-5 (mean difference 16.61, 95% CI 11.23 to 21.99). The IgG(2a)/IgE ratio and the IFN-gamma/IL-4 ratio was lower in the group of mice inoculated intranasally with 10(4) viable conidia than in the 10(4) non-viable conidia group and the controls. When proteins were extracted from P chrysogenum conidia, attached to microtitre plates and incubated with serum from the 10(4) viable group, significant increases in conidia-specific IgE and IgG(1) were observed compared with controls, while serum from the 10(4) non-viable group was similar to controls. CONCLUSIONS: These data suggest that long term inhalation of viable P chrysogenum propagules induces type 2 T helper cell mediated (Th2) inflammatory responses such as increases in total and conidia-specific serum IgE and IgG(1), together with BAL fluid levels of IL-4 and IL-5 and peripheral and airway eosinophilia, which are mediators of allergic reactions.

Administration, Intranasal↗
PubMed2000

Conglutinin and immunoconglutinin titers in stressed calves in a feedlot.

OBJECTIVE: To determine whether increased conglutinin titers are evident in stressed calves that do not develop respiratory tract disease in feedlots, compared with respiratory tract disease, and to determine the increase in immunoconglutinin titers. ANIMALS: 101 mixed-breed beef calves. PROCEDURE: Calves were processed at 4 farms of origin and allowed to remain with their dams for another 100 days. Calves from each farm were brought to a centrally located order-buyer barn. In a feedlot, 101 calves were assigned to pens and observed daily for clinical signs of acute respiratory tract disease. When sick calves were detected, they were treated with antibiotics and isolated in a pen for 4 days. Conglutinin and immunoconglutinin titers were determined for all calves. RESULTS: During the 28-day study, 73 calves developed respiratory tract disease, whereas 28 calves remained healthy. Mean conglutinin titers differed significantly among calves from the 4 farms. Significant differences were not detected in conglutinin titers among calves on the basis of sex, morbidity, or vaccination status against Mannheimia haemolytica at each farm, the order-buyer barn, or the feedlot on days 8, 15, and 28 after arrival. Immunoconglutinin titers in calves differed significantly among farms and morbidity status. CONCLUSIONS AND CLINICAL RELEVANCE: Mean conglutinin titers in calves do not appear to be associated with the incidence of acute respiratory tract disease; however, increased immunoconglutinin titers appear to be associated with recovery of stressed calves from respiratory tract disease during the first 15 days after arrival in a feedlot.

Animals↗
PubMed1999

Continually measured fungal profiles in sick building syndrome.

Buildings with indoor air quality (IAQ) complaints frequently have high airborne concentrations of Penicillium species, while buildings with few IAQ complaints have an indoor air (IDA) fungal ecology similar to outdoor air (ODA), where Cladosporium species is usually the dominant microorganism. These studies compared fungal air profiles, measured continually over 6 h in a documented sick building, in IDA in a room experiencing IAQ problems with fungal profiles measured concurrently in ODA. The dominant species collected at both sites were Penicillium species, Cladosporium species, and Alternaria species. In the IDA, Penicillium species were always the dominant organisms, ranging from 150 to 567 cfu/m3 (89.8-100% of the total fungi). In the ODA, Cladosporium species were dominant in four samples (40.0-70.6%), while Penicillium species were dominant (52.7-79.6%) in two. These data demonstrate that, even though ODA fungal profiles are changing continuously, IDA fungal profiles in "sick" buildings tend to remain unchanged.

Air Microbiology↗
PubMed1998

Cross-protection studies with three serotypes of Pasteurella haemolytica in the goat model.

Cross-protection studies employing three serotypes of Pasteurella haemolytica (Ph) were performed in goats, with challenge exposure by transthoracic injection. Indirect hemagglutination (IHA) serum titers showed that the herd had been naturally infected with Ph biovar A, serovar 2 (PhA2) prior to the study. Sixty-four weanling male Spanish goats were randomly allotted to 16 groups. Fifteen goats were given two transthoracic injections into the lungs 21 days apart with live Pasteurella haemolytica biovar A, serovar 1 (PhA1) in agar beads. Fifteen goats were given two transthoracic injections into the lungs 21 days apart with live PhA2 in agar beads. Sixteen goats were given two transthoracic injections into the lungs 21 days apart with live P. haemolytica biovar A, serovar 6 (PhA6) in agar beads. Eighteen control (CON) goats were given two transthoracic injections into the lungs 21 days apart with agar beads alone. Fourteen days after the second injection, goats were challenge-exposed to either live PhA1, PhA2, or PhA6 by transthoracic injection into the lung, and 4 days later, all goats were euthanatized and necropsied. Serum antibody to P. haemolytica antigens was measured throughout the experiment. Mean volumes of consolidated lung tissue for the CON goats challenged with PhA1, PhA2, and PhA6 were 28.29 cm3, 8.36 cm3, and 16.29 cm3, respectively. Mean volumes of consolidated lung tissue for the PhA1-immunized goats challenged with PhA1, PhA2, and PhA6 were 4.38 cm3, 0.25 cm3, and 1.90 cm3, respectively. Mean volumes of consolidated lung tissue for the PhA2-immunized goats challenged with PhA1, PhA2, and PhA6 were 9.68 cm3, 0.05 cm3, and 3.39 cm3, respectively. Mean volumes of consolidated lung tissue for the PhA6-immunized goats challenged with PhA1, PhA2, and PhA6 were 14.05 cm3, 1.27 cm3, and 4.53 cm3, respectively. These data demonstrate protection in immunized goats challenged with the homologous serotype of P. haemolytica. PhA1-immunized animals were protected against serotype 2 challenge as well as against serotype 6 challenge. PhA2-immunized animals were not protected against serotype 1 challenge, but were protected against transthoracic PhA6 challenge. PhA6-immunized animals were not protected against serotype 1 challenge, but were protected against transthoracic PhA2 challenge. There appears to be some cross-protection among the P. haemolytica serotypes, and this fact should be taken into consideration when developing vaccines against this organism.

Animals↗
PubMed1998

Pasteurella haemolytica ultraviolet-irradiated vaccine by parenteral and aerosol routes compared in the goat model.

Positive control 1 (PC1) (n = 9) goats were injected transthoracically into the left lung with live Pasteurella haemolytica biovar A, serovar 1 (PhA1) in polyacrylate (PA) beads on days 0 and 21. Positive control 2 (PC2) (n = 6) goats were nebulized with live PhA1 and PA beads on days 0 and 21. Negative control (NC) goats (n = 6) were each injected transthoracically into the left lung with PA beads alone on days 0 and 21. Four groups (n = 6) were administered PA beads mixed with ultraviolet (UV) killed PhA1 on days 0 and 21. The treatment doses of bacteria for these groups were principal group 1 (PR1) injected into the left lung (7.7 x 10(10) cfu); PR2, 7.7 x 10(10) UV-killed PhA1 injected subcutaneously (SC); PR3, 7.7 x 10(10) UV-killed PhA1 injected SC only on day 21; PR4, nebulized with PA beads mixed with 5.6 x 10(10) cfu of UV-killed PhA1; and PR5, nebulized with PA beads mixed with 5 x 10(8) cfu of UV-killed PhA1. All goats were challenged transthoracically in the right lung with 1 x 10(8) cfu of live PhA1 on day 42 and necropsied on day 46. The sizes of consolidated lung lesions at the challenge site were used as a measure of immunity. The data show that the introduction of live PhA1 into the lungs of goats, either by injection or aerosolization, offers excellent protection against a subsequent homologous challenge. The data also demonstrate that two transthoracic injections (21 days apart) of UV-killed PhA1 (PR1), and subcutaneous injection of UV-killed PhA1(PR2) also offer excellent protection against a subsequent homologous live PhA1 challenge. One SC injection of UV-killed PhA1 (PR3) appears to offer only partial protection against a subsequent homologous live PhA1 challenge. Inhalation of UV-killed PhA1 mixed with PA beads (PR4 and PR5) induced no protection in goats against a subsequent live PhA1 transthoracic challenge.

Aerosols↗