Prevalence of serological response to Borrelia burgdorferi in farmers from eastern and central Poland.

Lyme borreliosis (Lyme disease) caused by the Borrelia burgdorferi sensu lato spirochete is the most common tick-borne infection manifested by a wide spectrum of clinical symptoms. In Poland, the preventive health care does not comprise individual farmers as it is practiced in foresters. The objective of this study was to evaluate the exposure of Polish farmers to infection with B. burgdorferi, based on serological screening test and epidemiological investigation. A total of 3,597 farmers were examined for the presence of B. burgdorferi antibodies, as well as interviewed regarding exposure to ticks and prophylaxis of tick-borne diseases. The prevalence varied between 18.2 and 50.7 % suggesting a focal occurrence of borreliosis. A significant increase in the frequency of positive reactions in the oldest age ranges was observed, equaling 30.9 % in the range of 60-69 years and 53.6 % in the range of 80-91 years. The prevalence of the anti-B. burgdorferi antibodies of IgG class (14.7 %) was similar to that of IgM class (16.0 %). Seroreactivity to B. burgdorferi antigen was significantly higher in the group of farmers exposed to repeated tick bites. Significant relationships were also found between some other risk factors and occurrence of seropositive reactions to B. burgdorferi. To the best of our knowledge, this is the first study concerning seroprevalence to B. burgdorferi carried out on such a large group of farmers. Results indicate a high risk of B. burgdorferi infection among Polish farmers and associations between some risk factors and the presence of seropositive reactions.

Cathelicidin related antimicrobial peptide, laminin, Toll-like receptors and chemokines levels in experimental hypersensitivity pneumonitis in mice.

INTRODUCTION: Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by unresolved inflammation and tissue repair pathologies triggered by repeated organic dust exposure. The aim of the study was to investigate changes in levels of the cathelicidin related antimicrobial peptide (CRAMP), laminin (LAM-A1), selected Toll-like receptors (TLR) and chemokines in experimental HP in mice. MATERIALS AND METHODS: Three and 18-month-old female C57BL/6J mice underwent inhalations of the saline extract of Pantoea agglomerans cells, Gram-negative bacterium common in organic dust and known for its pathogenic impact. The inhalations were repeated daily (28 days). ELISA was used for measuring in lung tissue homogenates concentration of CRAMP, LAM-A1, TLR2, TLR4, TLR8, CXCL9 (chemokine [C-X-C motif] ligand) and CXCL10. RESULTS: Levels of TLR2, TLR4 and CXCL9 were significantly higher in both young and old mice lungs already after 7 days of inhalations, while significant increase of LAM-A1 and CXCL10 was noted after 28 days, compared to untreated samples. TLR8 level was significantly augmented only in young mice. Only CRAMP level significantly declined. Significantly higher TLR8 and CXCL9 concentration in untreated samples were noted in old animals compared to young ones. CONCLUSION: Significant alterations of the examined factors levels indicate their role in HP pathogenesis.

Cathelicidin LL-37 in bronchoalveolar lavage and epithelial lining fluids from healthy individuals and sarcoidosis patients.

Sarcoidosis is a granulomatous disease of unknown etiology most often characterized by pulmonary manifestations. Changes in an innate immune system, involving antimicrobial peptides, have been noted during the course of pulmonary sarcoidosis. This study focuses on the level of LL-37 peptide, the only human cathelicidin, additionally characterized by a wide range of pleiotropic activities, in pulmonary sarcoidosis. A cross-sectional study was conducted in groups of 32 patients with sarcoidosis and 12 healthy individuals. Bronchoalveolar lavage fluid (BALF) sampling, followed by LL-37 measurements by mass spectrometry combined with previous immunoaffinity purification, was performed. Based on urea levels, concentrations of LL-37 in epithelial lining fluid (ELF) were calculated. The levels of LL-37 peptide in BALF samples derived from patients with pulmonary sarcoidosis (median: 17.45 pg/ml, 25th-75th percentile: 8.05-28.33 pg/ml) were significantly higher compared to the healthy group (median: 6.38 pg/ml, 25th-75th percentile: 4.90-11.55 pg/ml) (U Mann-Whitney test, p=0.04). Assessment of LL-37 in ELF confirmed the differences across the groups that were observed in BALF. The level of LL-37 in patients with sarcoidosis (median: 2.25 ng/ml, 25th-75th percentile: 1.03-5.06 ng/ml) was again higher compared to healthy individuals (median: 0.62 ng/ml, 25th-75th percentile: 0.43-2.17 ng/ml) (p=0.06, Mann-Whitney U test). The results of this study demonstrate that the level of LL-37 peptide is elevated in pulmonary compartment affected by sarcoidosis. This might have a meaning in the pathomechanism of the disease, especially taking into consideration versatile activity of human cathelicidin revealed in numerous experimental studies during the last years.

Relationship between COPD and lower socioeconomic status in farmers from South-Eastern Poland (Lublin region).

INTRODUCTION: Lower socioeconomic status is considered to be an independent risk factor of chronic conditions, such as chronic obstructive pulmonary disease (COPD). COPD, one of the major public health problems worldwide, is a chronic inflammatory lung disease of a multifactorial background. COPD morbidity in rural areas has been higher than in urban settings, as apart from the major causative factor, tobacco smoking, the burden of this disease in rural environments is also connected to additional occupational factors (organic dusts). The management of chronic diseases seems to be particularly difficult in rural areas. The aim of the study was to analyze the socioeconomic status of farmers suffering from COPD in comparison to healthy farmers. METHODS: Thirty farmers with COPD and 34 healthy farmers from the Lublin region (Poland) were investigated based on the area of land they possessed (an indicator used in the health insurance system in Poland to classify farmers). The farmers from five rural communes were selected by general practitioners. Statistical analysis was performed by non-parametric Mann-Whitney U-test for the differences between area of farms. The p < 0.05 level was considered as significant. RESULTS: Area of land (median: 1.5 ha, 25th-75th percentile: 1.0-4.0) owned by farmers with COPD was significantly lower than area of farms belonging to healthy farmers (median: 7.0 ha, 25th-75th percentile: 3.0-10.0) (p < 0001, Mann-Whitney U-test). CONCLUSIONS: In rural areas individuals with COPD are characterized by significantly lower socioeconomic status than healthy persons. COPD is a major health problem, especially in rural areas, which may indicate that policy-makers should consider addressing equity in COPD management in rural areas.

Cathelicidin LL-37 in bronchoalveolar lavage and epithelial lining fluids from COPD patients and healthy individuals.

Innate immunity is currently under scope of interest concerning its role in the development of chronic obstructive pulmonary disease (COPD). Antimicrobial peptides constitute a potent part of this fast response system. Here, we focus on the role of a specific antimicrobial peptide, the only human cathelicidin, the pleiotropic LL-37 peptide, in the development of COPD under clinical conditions. A cross-sectional study was conducted in groups of 43 patients with COPD (previously classified according to GOLD) and 12 healthy individuals. Bronchoalveolar lavage fluid (BALF) sampling, followed by LL-37 measurements by mass spectrometry combined with previous immunoaffinity purification, was performed. Based on urea levels, concentrations of LL-37 in epithelial lining fluid (ELF) were calculated. Additionally, an antimicrobial assay of growth inhibition of two bacterial species, often involved in COPD development mechanisms, by purchased LL-37 was conducted. Altogether, 55 BALF samples were analyzed. LL-37 levels were significantly higher in BALF from patients in early stages of COPD (GOLD I-II) compared to BALFs from healthy individuals. The same was true for ELF. Cathelicidin’s concentration was significantly lower in both BALF and ELF from patients in advanced COPD (GOLD III-IV). The significantly elevated LL-37 levels both in BALF and ELF in patients with COPD at stage GOLD I-II together with reduced levels in advanced (COPD stage III-IV) further supports the innate immunity involvement in COPD pathology and suggests a profound change in non-specific immunity during the disease progression.

HRTEM studies of amorphous ZrNiTiCu nanocrystalline composites.

Ball milling of easy glass forming Ti(25)Zr(17)Ni(29)Cu(29) alloys lead to the formation of an amorphous structure accompanied by a substantial increase of powder microhardness. The powders show clear glass transition effect and a few stage crystallization starting above 500 degrees C. High-resolution transmission electron microscope technique allowed identifying nanocrystalline inclusions as Cu(12)NiTi(7) within the amorphous powder. The amorphous powders mixed with nanocrystalline iron or silver powders were hot pressed to form composites. A narrow 200 nm broad intermediate single-phase layer at the amorphous-phase/iron interface containing all elements present in the composite was identified using transmission electron microscope and high-angle annular dark field detector techniques. scanning transmission electron microscopy energy dispersive spectroscopy line profile showed gradual change of composition within the intermediate zone. Amorphous phase contains small nanocrystals of size close to 10 nm identified using High-resolution transmission electron microscope as Cu(12)NiTi(7.) Compression tests have shown better plasticity of composites than in the case of pure hot-pressed amorphous powder; furthermore, high elastic limit of composites and the ultimate compression stress of about 1800 MPa for composites containing 20% Fe and near 700 MPa for those with 20% Ag.

Structure investigations of ferromagnetic Co-Ni-Al alloys obtained by powder metallurgy.

Elemental powders of Co, Ni and Al in the proper amounts to obtain Co(35)Ni(40)Al(25) and Co(40)Ni(35)Al(25) nominal compositions were ball milled in a high-energy mill for 80 h. After 40 h of milling, the formation of a Co (Ni, Al) solid solution with f.c.c. structure was verified by a change of the original lattice parameter and crystallite size. Analytical transmission electron microscopy observations and X-ray diffraction measurements of the final Co (Ni, Al) solid solution showed that the crystallite size scattered from 4 to 8 nm and lattice parameter a = 0.36086 nm. The chemical EDS point analysis of the milled powder particles allowed the calculation of the e/a ratio and revealed a high degree of chemical homogeneity of the powders. Hot pressing in vacuum of the milled powders resulted in obtaining compacts with a density of about 70% of the theoretical one. An additional heat treatment increased the density and induced the martensitic transformation in a parent phase. Selected area diffraction patterns and dark field images obtained from the heat-treated sample revealed small grains around 300 nm in diameter consisting mainly of the ordered gamma phase (gamma'), often appearing as twins, and a small amount of the L1(0) ordered martensite.

Microstructure evolution in hot worked steel after heating to semi-solid state.

Metal alloys can be formed successfully in a partially liquid state if they display a particular globular microstructure. The article presents an analysis of a study carried out of the development, by means of the strain-induced melt-activated method, of such a microstructure for an X210CrW12 steel. Hot rolled samples, with subsequent cooling, were heated to the temperature range at which the liquid and solid phases coexist in the material. The spheroidal shapes for solid particles, required for semi-solid processing, were found. The investigations were carried out using scanning electron microscopy in combination with energy dispersive spectroscopy.

TEM and HRTEM studies of ball milled 6061 aluminium alloy powder with Zr addition.

The effect of mechanical alloying on the microstructure of atomized 6061 aluminium alloy powder and 6061 powder with a zirconium addition was studied in the work. The atomized 6061 aluminium alloy powder and 6061 powder with addition of 2 wt.% Zr were milled in a planetary ball mill and investigated using X-ray diffraction measurements, conventional and high-resolution electron microscopy (TEM/HRTEM) and high-angle annular dark field scanning transmission electron microscopy combined with energy dispersive X-ray microanalysis. An increase of stresses was observed in milled powders after the refinement of crystallites beyond 100 nm. In the powder with zirconium addition, some part of the Zr atoms diffused in aluminium forming a solid solution containing up to 0.5 wt.% Zr. The remaining was found to form Zr-rich particles containing up to 88 wt.% Zr and were identified as face centred cubic (fcc) phase with lattice constant a= 0.48 nm. That fcc phase partially transformed into the L1(2) ordered phase. Eighty-hour milling brought an increase of microhardness (measured with Vickers method) from about 50 HV (168 MPa) for the initial 6061 powder to about 170 HV (552 MPa). The addition of zirconium had no influence on the microhardness.

Microstructure of friction stir welded joints of 2017A aluminium alloy sheets.

The present study examines a friction stir welded 2017A aluminium alloy. Transmission electron microscope investigations of the weld nugget revealed the average grain size of 5 microm, moderate density of dislocations as well as the presence of nanometric precipitates located mostly in grains interiors. Scanning electron microscope observations of fractures showed the presence of ductile fracture in the region of the weld nugget with brittle precipitates in the lower part. The microhardness analysis performed on the cross-section of the joints showed fairly small changes; however, after the artificial ageing process an increase in hardness was observed. The change of the joint hardness subject to the ageing process indicates partial supersaturation in the material during friction stir welding and higher precipitation hardening of the joint.

Microstructure and properties of hot compacted powders of aluminium alloys.

Atomized 6061 aluminium alloy powders with and without the addition of 2 wt% Zr were milled for 80 h in a planetary ball mill and hot pressed in vacuum. The milled powders showed microhardness of about 170 HV, which increased after hot pressing up to 260 HV and up to 280 HV for powders without and with the Zr additions, respectively. Compression tests showed the high yield stress of 300 MPa obtained for the hot-pressed sample produced from the initial powders compared with ultimate compression strength of above 800 MPa for that of the milled sample and slightly higher for that with Zr additions. The effect of hot pressing on the structure of powders was investigated using a conventional analytical and high-resolution electron microscopy and high angle annular dark-field scanning transmission electron microscopy combined with energy dispersive X-ray microanalysis. The samples of initial powders hot pressed in vacuum showed a cell structure with particles of the Mg(2)Si and AlFeSi phases in intercell areas. In the milled and hot-pressed sample, the homogeneous structure of small grains of size below 200 nm was observed. The AlFeSi and Mg(2)Si particles with size 20-100 nm were uniformly distributed as well as the Zr rich particles in the Zr containing alloy. The Zr-rich particles containing up to 80 at% Zr were identified as a metastable fcc cubic phase with lattice parameter a= 0.48 nm.

HRTEM studies of NiNbZr + Ag amorphous-nanocrystalline composites.

Amorphous powder of composition corresponding to Ni60Ti20Zr20 (in at%) was obtained by ball milling in a high-energy mills starting from pure elements. Formation of the amorphous structure was observed already after 20 h of milling, although complete amorphization occurred after 40 h. The microhardness of powders increased from about 30 HV for pure elements to above 400 HV (1290 MPa) after 40 h of milling. Transmission electron microscopy (TEM) allowed to identify nanocrystalline inclusions of intermetallic phases of size 2-10 nm. Uniaxial hot pressing was performed in vacuum at temperature below the crystallization T(x) it is 510 degrees C and pressure of 600 MPa, Mixed amorphous powders and nanocrystalline silver powders were used to form a composite, in which microhardness was near 970 MPa HV and 400 HV for the amorphous phase and nanocrystalline silver, respectively. The compression strength of the composite containing 20 wt% of nanocrystalline Ag powder was equal to 600 MPa and plastic strain was 2%. Microstructure studies showed low porosity of composites of less than 1%, uniform distribution of the silver phase and a transition zone between both components, about 150 nm thick, where diffusion of nickel, niobium and zirconium into silver was observed. High-resolution TEM allowed identifying the structure of nanocrystalline inclusions in the amorphous matrix after hot pressing as either Ni(3)Zr or Ni(17)Nb(3). The identification was performed basing on measurements of angles and interatomic distances using inverse Fourier transformed images with enhanced contrast using Digital Micrograph computer program.

Microstructure of ball milled and compacted Co-Ni-Al alloys from the beta range.

Two powder alloys from the beta phase region of compositions Co(28.5)Ni(36.5)Al(35) and Co(35)Ni(30)Al(35) were ball milled for 80 h in a high energy ball mill. The formation of amorphous structure was observed after 40 h of milling and further milling did not change their structure. The analytical and high-resolution transmission electron microscopy (TEM, HREM) examination of powder structure showed that nanoparticles of L1(0) phase of size of about 5 nm were present within the amorphous matrix. The vacuum hot pressing of the milled powders under pressure of 400 MPa at 700 degrees C for 12 min resulted in the formation of compacts with density of about 70% of the theoretical one. The additional heat treatment at 1300 degrees C for 6 h followed by water quenching, led to significant improvement of density and induced the martensitic transformation manifested by a broad heat effect. The characteristic temperatures of the transformation were determined using DSC measurements, which revealed only small differences within the examined alloys compositions. TEM structure studies of heat-treated alloys allowed to identify the structure of an ordered beta (B2) phase and L1(0) martrensite.

HRTEM and TEM studies of amorphous structures in ZrNiTiCu base alloys obtained by rapid solidification or ball milling.

Amorphous structure of Ti(25)Zr(17)Ni(29)Cu(29) composition was studied. Alloys were prepared either by rapid solidification using melt spinning or by high-energy ball milling. The composition of multi-component eutectic in slowly cooled samples of ZrNiTiCu alloy was determined using EDS measurements in scanning microscope of slowly cooled cast samples. The alloys of eutectic composition were melt-spun or ball-milled. Transmission electron microscopy (TEM) studies of melt-spun ribbons from alloys near eutectic composition did not show presence of nanocrystals within the amorphous structure. TEM studies of ball-milled powders showed presence of nanocrystallites of size 2-5 nm. The electron diffraction pattern showed intense diffused ring due to the presence of the amorphous phase and a weak spot due to crystalline phases which were difficult to identify. The high temperature high-pressure compaction in vacuum of amorphous ball-milled powders resulted in a similar structure like in the powders showing nanocrystals embedded in the amorphous matrix. The crystallites were imaged using HREM. Interplanar distances were measured in pictures obtained by inverse fast Fourier transform (IFFT) of atomic planes to obtain better contrast. Analysis of the IFFT from high-resolution micrographs allowed to identify Cu(10)Zr(7) phase. Point analysis and elemental mapping performed using nondispersive X-ray energy spectroscopy showed uniform elements distribution indicating that chemical segregation to nanocrystals is within measurement error.

Transmission electron microscopy studies of microstructure of Ti-Nb and Ti-Ta alloys after ball milling and hot consolidation.

Two Ti alloys with compositions Ti-10Ta and Ti-10Nb (at.%) were milled in a high-energy mill for a maximum of 80 h in an argon atmosphere. A nanocrystalline structure of alpha-Ti(X) (X = Ta or Nb) solid solution was formed in both investigated alloys after milling, as shown by X-ray diffraction. Transmission electron microscopy observations of powders milled for 80 h revealed chemical inhomogeneity of particles in nanometre-scale regions and an average crystallite size of about 10 nm. The pulse plasma sintering method was applied for hot consolidation of milled powders. The mean density of pulse plasma sintering compacts of Ti-Nb alloy was about 99.5% of the theoretical value, whereas the density of the Ti-10Ta sample was lower, close to 92% of the theoretical value. Transmission electron microscopy observation of compacted samples showed that the sintering process caused the formation of a two-phase alpha + beta structure in both investigated alloys, with a mean grain size of 220 nm. The chemical inhomogeneity and high degree of deformation in nanometre-scale regions of milled powders led to a martensitic transformation, resulting in formation of a 9R martensite structure.

TEM and HREM study of Al3Zr precipitates in an Al-Mg-Si-Zr alloy.

The structure of Al(3)Zr precipitates in Al-1.0Mg-0.6Si-0.5Zr (in wt.%) alloy was investigated using conventional transmission electron microscopy (TEM) and high-resolution TEM (HREM). After annealing of the alloy in the temperature range 450-540 degrees C, spherical precipitates of metastable L1(2)-Al(3)Zr phase appeared nearly homogeneously within the matrix, and elongated particles were found at grain boundaries. L1(2)-structured Al(3)Zr were about 20-30 nm in diameter and coherent with the matrix. Inside some of them, planar faults parallel to {100} planes were revealed by use of HREM. Most probably, these faults are an indication of the transition stage of transformation to the stable D0(23)-type Al(3)Zr phase. The elongated precipitates (about 100 nm) were identified as D0(22)-type Al(3)Zr. Energy-dispersive X-ray analysis showed that they contain, apart from Al, mainly Zr with small amounts of Si. The substitution of Al by Si increased the stability of the D0(22)-Al(3)Zr as compared with D0(23)-Al(3)Zr.

Structure studies of ball-milled ZrCuAl, NiTiZrCu and melt-spun ZrNiTiCuAl alloys.

ZrNiTiCu and ZrNiTiCuAl alloys were amorphized using either a melt-spinning or ball-milling process in a high-energy planetary mill. The elemental powders were initially blended to the desired composition (in at.%) of Zr, 65; Cu, 27.5; Al, 7.5 and of Ti, 25; Zr, 17; Cu, 29; Ni, 29, respectively. The composition of alloys was chosen to be the same as for the bulk amorphous ZrCuAl and easy glass-forming ZrNiTiCu alloys. An almost fully amorphous structure was obtained after 80 h of milling in the case of both compositions. Transmission electron microscopy studies of ball-milled powders revealed the presence of nano-crystallites [2-5 nm for ZrCuAl and smaller (1-3 nm) for the ZrTiNiCu alloy]. High-resolution transmission electron microscopy of melt-spun ZrNiTiCuAl ribbons provided evidence of the amorphous structure.

Exposure to airborne microorganisms in fiberboard and chipboard factories.

Microbiological air sampling was performed in one fiberboard factory and two chipboard factories located in south-eastern Poland. It was found that the levels of bacteria, fungi, dust and bacterial endotoxin in the air of examined facilities were high during initial stages of the production cycle (shredding of waste wood, storing of chips) and then sharply decreased during further stages of this cycle (forming and formatting of the boards). In the fiberboard factory, the concentration of airborne microorganisms at the initial stages of production cycle was 71.8-95.2 x 10(3) cfu/m3 and dropped in further stages to the level of 8.4-17.5 x 10(3) cfu/m3. Fungi (mostly Aspergillus fumigatus and Penicillium spp.) were prevailing microorganisms in the air of the fiberboard factory, forming 46.0-87.3% of the total airborne microflora. The concentrations of microorganisms in the air of the chipboard factories were significantly lower compared to the fiberboard factory (p<0.05). During initial stages of production cycle they were within the range of 12.9-101.5 x 10(3) cfu/m3, while during forming and formatting of boards within the range of 5.3-12.4 x 10(3) cfu/m3. On average, the most common microorganisms in the air of the chipboard factories were corynebacteria (mostly Arthrobacter spp. and Corynebacterium spp.) which formed 24.4-64.6% of the total microflora. The values of the respirable fraction of airborne microflora in the fiberboard and chipboard factories varied within a fairly wide range and were between 20.5-91.1%. Altogether, 38 species or genera of bacteria and 16 species or genera of fungi were identified in the air of examined factories, of which respectively 14 and 9 species or genera were reported as having allergenic and/or immunotoxic properties. The concentration of bacterial endotoxin in the air of examined factories was greatest, similarly to the concentration of microorganisms, during the initial stages of the production cycle: 103.1-1974.0 EU/m3 in the fiberboard factory, and 3.2-217.4 EU/m3 in chipboard factories. In conclusion, the workers of fiberboard and chipboard factories may be exposed during the initial stages of the production cycle (shredding of waste wood, storing of chips) to high levels of airborne microorganisms and endotoxin posing respiratory hazard.

Exposure to airborne microorganisms and endotoxin in herb processing plants.

Microbiological air sampling was performed in two herb processing plants located in eastern Poland. Air samples for determination of the levels of bacteria, fungi, dust and endotoxin were collected at 14 sites during cleaning, cutting, grinding, sieving, sorting and packing of 11 kinds of herbs (nettle, caraway, birch, celandine, marjoram, mint, peppermint, sage, St. John's wort, calamus, yarrow), used for production of medications, cosmetics and spices. It was found that processing of herbs was associated with a very high pollution of the air with bacteria, fungi, dust and endotoxin. The numbers of microorganisms (bacteria and fungi) in the air of herb processing plants ranged within 40.6-627.4 x 10(3) cfu/m3 (mean +/- S.D = 231.4 +/- 181.0 x 10(3) cfu/m3). The greatest concentrations were noted at the initial stages of production cycle, during cleaning, cutting and grinding of herbs. The numbers of airborne microorganisms were also significantly (p<0.0001) related to the kind of processed herb, being the greatest at processing marjoram, nettle, yarrow and mint. The values of the respirable fraction of airborne microflora in the examined facilities varied within a fairly wide range and were between 14.7-67.7%. The dominant microorganisms in the air of herb processing plants were mesophilic bacteria, among which endospore-forming bacilli (Bacillus spp.) and actinomycetes of the species Streptomyces albus were most numerous. Among Gram-negative bacteria, the most common was endotoxin-producing species Alcaligenes faecalis. Altogether, 37 species or genera of bacteria and 23 species or genera of fungi were identified in the air of herb processing plants, of these, 11 and 10 species or genera respectively were reported as having allergenic and/or immunotoxic properties. The concentrations of dust and bacterial endotoxin in the air of herb processing plants were large with extremely high levels at some sampling sites. The concentrations of airborne dust ranged within 3.2-946.0 mg/m3 (median 18.1 mg/m3), exceeding at 13 out of 14 sampling sites the Polish OEL value of 4 mg/m3. The concentrations of airborne endotoxin ranged within 0.2-2681.0 microg/m3 (median 16.0 microg/m3), exceeding at all sampling sites the suggested OEL value of 0.1 microg/m3. In conclusion, the workers of herb processing plants could be exposed to large concentrations of airborne microorganisms, dust and endotoxin posing a risk of work-related respiratory disease.

Enzymatic activities of Aspergillus fumigatus strains isolated from the air at waste landfills.

Out of 15 Aspergillus fumigatus strains isolated from the air at waste landfills, all revealed cellulolytic and lipolytic activities. Eleven out of 15 strains showed very strong cellulolytic properties, as assessed by the viscosimetric test for endo-1,4-beta-glucanase activity (EGA). None of the examined strains revealed a well-expressed proteolytic activity. The results suggest that Aspergillus fumigatus strains developing in stored wastes produce strong cellulotytic enzymes which need further studies for the potential allergenic and/or immunotoxic effects of these proteins on exposed workers.