Multifactorial aetiology of recurrent respiratory tract infections in children

Recurrent respiratory tract infections in children are a common health problem. Exposure to harmful environmental agents and coexistence of chronic diseases affect the severity and rate of infections. Ineffective outpatient treatment is an indication for a more comprehensive diagnostic workup. The aim of the study was to determine the cause of recurrent respiratory tract infections in children. The study group included 130 children aged 3–17 years who were referred for diagnostic investigation to determine the cause of recurrent respiratory tract infections. The eligibility criterion for the study group was the occurrence of 8 or more respiratory tract infections a year in children aged up to 6 years and 5 or more infections a year in children aged 7–17 years. The study group was subdivided into the following age groups: 3–5 years (n = 60), 6–9 years (n = 35), 10–13 years (n = 11) and 14–17 years (n = 24). The presence of potential risk factors for recurrent infection was analysed on the basis of questionnaires. Tests and examinations were also performed in order to exclude allergies, ear, nose and throat disorders and gastroesophageal reflux disease. Selected laboratory values (complete blood count, vitamin D concentration, immunoglobulin levels) were compared with those obtained from 86 healthy children from the control group. The majority of children had risk factors for recurrent respiratory tract infections. Adenoid hypertrophy was diagnosed in 44.6% of children, asthma in 36.9%, vitamin D deficiency in 30.7%, gastroesophageal reflux disease in 16.2% and immunodeficiency in 9.2% of children. Multimorbidity was found in 34.6% of the subjects. In the study group, there were higher vitamin D levels [study group: 25.6 ng/mL (25th percentile = 17; 75th percentile = 33.3), control group: 22.84 ng/mL (25th percentile = 16.3; 75th percentile = 28.7); p < 0.044] and higher leukocyte levels [study group: 7.5 × 103/μL (25th percentile = 5.9; 75th percentile = 9.1), control group: 6.4 × 103/μL (25th percentile = 5.3; 75th percentile = 7.7); p < 0.02]. The results indicate that children with recurrent respiratory tract infections are a heterogeneous group of patients. The youngest children were the largest group (n = 60). In the majority of children, the onset of symptoms was associated with the beginning of nursery/preschool or school attendance. In 1 in 3 children, a combined presence of a few diseases was found which increase susceptibility to recurrent respiratory tract infections.

A rare case of primary amenorrhoea and breast development in a 46,XY 15-year-old girl

A disorder of sex development (DSD) is defined as a congenital condition in which development of chromosomal, gonadal, or anatomical sex is atypical. Swyer syndrome is an example of 46,XY DSD with a female phenotype. It usually becomes apparent in adolescence with delayed puberty and amenorrhoea. Spontaneous breast development is very rare. A 15-year-old girl was presented due to primary amenorrhoea with breast development compatible with Tanner stage V. Hormonal tests revealed hypergonadotropic hypogonadism with low level of oestradiol. Pelvic ultrasound and magnetic resonance imaging revealed a small uterus, and no ovaries were found. In the right lower abdomen, a structure of unknown origin was visible. The chromosome analysis revealed a 46,XY karyotype. The patient was qualified for a laparoscopic bilateral gonadectomy. Postoperative histopathological examination revealed gonadoblastoma. We underline the need to consider DSD 46,XY in the presence of primary amenorrhoea, even when pubertal development is present. Germ cell tumors have a tendency to grow and metastasize rapidly. Delayed diagnosis may increase the risk of malignant transformation and cause a poor diagnosis.

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 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.

The influence of fatty acids on theophylline binding to human serum albumin. Comparative fluorescence study

Theophylline, popular diuretic, is used to treat asthma and bronchospasm. In blood it forms complexes with albumin, which is also the main transporter of fatty acids. The aim of the present study was to describe the influence of fatty acids (FA) on binding of theophylline (Th) to human serum albumin (HSA) in the high affinity binding sites. Binding parameters have been obtained on the basis of the fluorescence analysis. The data obtained for the complex of Th and natural human serum albumin (nHSA) obtained from blood of obese patients qualified for surgical removal of stomach was compared with our previous studies on the influence of FA on the complex of Th and commercially available defatted human serum albumin (dHSA).

Mouse model of hypersensitivity pneumonitis after inhalation exposure to different microbial antigens associated with organic dusts

The aim of this study was to reproduce in laboratory conditions hypersensitivity pneumonitis (HP) pathogenesis in a new animal model predictive of the human response, and to select the microbial antigen associated with organic dust that exerts the strongest pathogenic effect on the respiratory organ. To achieve this goal, mice of the strain C57BL/6J prone to fibrosis were exposed for 1 hour daily up to 28 days to the inhalation of aerosols of each of the 5 microbial components of organic dusts whose conjunction with the occurrence of HP has been confirmed by numerous authors: Pantoea agglomerans saline extract (SE), P. agglomerans microvesicle-bound endotoxin, Saccharopolyspora rectivirgula SE, Aspergillus fumigatus SE, saline extract of dust from a grain sample overgrown with S. rectivirgula and Thermoactinomyces vulgaris, and a saline solvent (PBS) was used as a control. Exposure of the animals to organic dust components was conducted using a novel inhalation challenge set. Lung samples were collected from untreated mice and from mice exposed for 7 and 28 days, and examined by digitalized histopathology and biochemistry for the presence of inflammatory changes and fibrosis. P. agglomerans SE appeared to be the sole antigen which evoked a statistically significant fibrosis and a significant increase of hydroxyproline in the lungs of mice exposed for 28 days to this extract, both compared to the mice untreated and to those exposed to the solvent. P. agglomerans SE also evoked the strongest and statistically significant inflammatory response in the lungs of the mice, both after 7 and 28 days of exposure. After 7 days, significant inflammatory changes were also found in mice exposed to A. fumigatus SE, and after 28 days in mice exposed to all antigens. In conclusion, our results allow us to define a useful animal model of HP which can be a supplement for now commonly used bleomycin model. This model should comprise: present set of instruments for inhalation, mice of the line C57BL/6J and the saline extract of P. agglomerans as the antigen. For a better understanding of the presented results, a detailed study covering immunological investigations, focused on the mechanism of antigen action, are needed.

Occupational exposure to organic dust, microorganisms, endotoxin and peptidoglycan among plants processing workers in Poland

The objective of present work was to determine and compare the components of bioaerosol in several sectors of plant processing industries. The study was conducted in 10 facilities engaged in herb and grain processing, flax threshing, grain storing, baking, and cereals production. The air samples were taken on glass fibre filters with an AS-50 sampler. We determined the concentrations of airborne microorganisms, dust, endotoxin and peptidoglycan. Total concentrations of viable airborne microorganisms ranged from 0.18-861.4 x 10(3) cfu/m(3). The highest levels of microbial contamination of the air were observed at flax farms, in grain elevators and in a herb processing plant. Gram-positive bacteria and fungi were detected at all sampling sites and their median concentrations were respectively 18.1 x 10(3) cfu/m(3) and 0.66 x 10(3) cfu/m(3). The concentration of Gram-negative bacteria ranged from 0.0-168.0 x 10(3) cfu/m(3). The concentration of thermophilic actinomycetes ranged from 0.0-1.45 x 10(3) cfu/m(3). Qualitatively, Gram-positive bacteria constituted 23-93% of the total microbial count. The most common species were: Staphylococcus spp., Curtobacterium pusillum, Rhodococcus fascians, Aureobacterium testaceum, Sanguibacter keddieii, Microbacterium spp., and Bacillus spp. Gram-negative bacteria formed 0-48% of the total count. The species Pantoea agglomerans dominated in all examined air samples. Fungi constituted 2.5-76.9% of the total microbial count. Among them, Penicillium spp., Mucor spp., Alternaria spp., Aspergillus niger, and Aspergillus spp. were found. The dust concentration ranged from 0.18-86.9 mg/m(3). The concentration of endotoxin was large and ranged from 0.0041-1562.6 microg/m(3). Muramic acid, the chemical marker of peptidoglycan, was detected in 9 out of 13 (69.2%) collected samples. The concentration of peptidoglycan ranged from 1.93-416 ng/m(3). A highly significant correlation was found between the individual components of bioaerosol determined in this study. The concentration of endotoxin was correlated with the concentration of Gram-negative bacteria, total microorganisms, and peptidoglycan (R>0.9, p<0.001). The concentration of peptidoglycan was correlated with the concentration of Gram-positive bacteria, Gram-negative bacteria, and total microorganisms (R>0.9, p<0.001).

Quantum chemical modeling of electrochromism of tungsten oxide films

A cluster model is proposed to describe the excitations in solid tungsten oxide. The density-functional theory approach is used to calculate the ground-state electronic structure of the model cluster and its optimum geometry; subsequently, time-dependent density-functional theory calculations are performed to obtain the oscillator strengths and energies of the excited states. The results are reported both for the electrically neutral cluster and for the cluster with an extra electron (mimicking the effect of electron injection from the cathode). They correctly locate the electrochemically active transition. The corresponding wave functions are delocalized, suggesting that electron localization at one tungsten center is rather unlikely, thereby shedding doubt as to the validity of the polaron model. Local lattice distortions presumably created at the stage of sample preparation are found to affect the excitation energies to a considerable extent, which explains the experimentally observable large width of optical absorption responsible for electrochromism.

Respiratory effects of exposure to dust from herbs

A group of 150 people occupationally exposed to dust from herbs were examined. As a reference group, 50 urban dwellers, not exposed to any kind of organic dust were examined. People were subjected to routine physical examination and to lung function examinations with the LUNGTEST 500 spirometer (MES, Kraków, Poland). The spirometric values of the forced expiratory volume in one second (FEV (1)), vital capacity (VC) and FEV(1)/VC were recorded before and after work. Physical chest examination revealed pathological crepitations in 10 people (6.7 %). The mean baseline spirometric values in the study and reference groups did not show significant differences compared to the normal values. In the herb workers exposed to organic dust the post-shift decrease of all analysed spirometric values was noted. The post-shift decrease of some spirometric values (VC, VC % of normal values) was highly significant (p < 0.01). There was evidenced of a significant positive correlation between the age of examined people and decrease of VC and FEV(1) values. In 12 exposed workers the decrease of FEV(1) or FEV(1) % of normal values higher than 15 % was noted. 50 % of these workers cultivated thyme (Thymus vulgaris L.). This may suggest that dust from herbs, especially thyme dust, may cause acute airway obstruction. In the group showing significant decrease of FEV(1)/FEV(1) % of normal values ( > 15 %) the frequency of reported respiratory work-related symptoms (83.3 %) was higher than in the rest of exposed group (61.5 %). In conclusion, occupational exposure to dust from herbs may cause harmful effects on the respiratory system among herb processing workers. This indicates the need for use of prophylactic measures in this professional group, the more so as number of people occupationally exposed to dust from herbs is growing.

Health effects of exposure to herb dust in valerian growing farmers

The aim of the present study was to determine the health status of farmers cultivating valerian (Valeriana officinalis L.) and occupationally exposed to dust from this plant. A group of 75 valerian growing farmers were examined. As a reference group, 50 urban dwellers, not exposed to any kind of organic dust were examined. All people were interviewed for the presence of work-related symptoms and subjected to physical and spirometric examinations. Skin prick tests were conducted with 4 microbial antigens associated with organic dust and 3 herbal extracts, precipitin tests with 12 microbial antigens and 4 herbal extracts and tests for specific inhibition of leukocyte migration with 4 microbial antigens. 30.7 % of the valerian farmers reported occurrence of work-related symptoms. No significant differences were found between the spirometric values in the group of valerian farmers and the reference group. Valerian farmers showed a low frequency of positive skin reactions to all tested antigens (0-4.0 %), not significantly greater compared to reference group. The frequency of positive precipitin reactions to the antigen of Gram-negative bacterium Pantoea agglomerans was very high in valerian farmers (45.5 %) with 3-fold concentrated sera and significantly greater compared to the reference group (p < 0.001). The positive precipitin response of valerian farmers to other microbial and herbal antigens was much lower or absent and did not show any difference compared to reference group. In the test for specific inhibition of leukocyte migration, the highest frequencies of positive reactions in valerian farmers were noted with Pantoea agglomerans and Saccharopolyspora rectivirgula (15.0 % each), in both cases significantly greater compared to reference group (p < 0.05). In conclusion, the farmers growing valerian showed a moderate frequency of work-related symptoms and low reactivity to most microbial and herbal allergens. They exhibited an increased immunologic response to Gram-negative bacterium Pantoea agglomerans which appears to be the most important risk factor associated with valerian dust.

Exposure to bioaerosols: allergic reactions and respiratory function in Polish hop growers

BACKGROUND

The aim of the study was to assess the prevalence of work-related symptoms in hop growers and their relation to bioaerosols exposure. The study group comprised 69 hop growers and 58 office workers as controls. The examination included: physician-administrated questionnaire, PEF measurements, skin prick test, agar-gel precipitation test, and migration inhibition test. Microbiological air sampling was performed on all farms.

RESULTS

The concentrations of total airborne microflora ranged from 2.08 to 129.6 x 10(3) CFU/m3. Airborne endotoxin and dust concentrations ranged from 26 to 6250 ng/m3 and 0.2-31.7 mg/m3, respectively. Altogether 52.2% of farmers complained of work-related symptoms. Positive skin reactions to microbial allergens were significantly more frequent in a group of hop growers with work-related respiratory symptoms compared to the rest of the farmers (18% vs 2%, P <0.05). Positive reactions in agar-gel precipitation test and in the leukocyte migration inhibition test were not correlated with the occurrence of work-related symptoms. The mean daily PEF values in farmers were lower compared to controls (469.7 +/- 127.5 vs 562.9 +/- 123.8; P <0.001). PEF (amp%mean) was higher in farmers compared to controls (9.3% vs 8.1%; P <0.05).

CONCLUSION

Despite relatively lower exposure to bioaerosols, compared to farmers in other branches of agriculture, over 50% of hop growers complained of work-related symptoms. This may be partly due to the effects of microbial allergens and toxins and partly to the irritant or allergic properties of hop plant itself.

Working Group report 1: tools for the diagnosis of organic dusts-induced disease

This paper describes the outcomes of the discussion of Working Group 1. The tasks of the workgroup were to: i) review current methods for the clinical diagnosis of organic dust induced disease, and ii) suggest how further research in this field should proceed. The working group proceeded on the paradigm that for diagnosis specific and precise tests are needed, where outcomes can be related to the risk for disease. The different methods available for the investigation of individuals and groups exposed to organic dusts are summed and graded according to scientific or diagnostic values. Many of the tools should be used in experimental research only, but can be used diagnostically for evaluation during follow up of patients when treated or removed from exposure. These techniques may also be employed for investigations of outbreaks, however, only after comparison with a proper control group. Future research should focus on associations between markers of inflammation and symptoms or clinical outcomes and dose-response relationships both for short-term and long-term health effects.

Health effects of inhalation exposure to organic dust in hops farmers

Medical examinations were performed in a group of 23 hops farmers exposed to organic dust from hop (Humulus lupulus). The examinations took place in individual farms during harvesting, sorting and transporting of hop cones. As a reference group, 50 urban dwellers not exposed to organic dust were examined. There were conducted physical examinations, interviews concerning the occurrence of respiratory disorders and work-related symptoms, lung function tests, determination of cytokines concentrations, and allergological tests comprising skin prick test with 4 microbial antigens associated with organic dust, precipitin test with 12 microbial antigens, and a test for inhibition of leukocyte migration. Five farmers (21.7%) reported occurrence of work-related symptoms, including dry cough and dyspnoea. Eight farmers (34.8%) reported symptoms of chronic bronchitis. Mean spirometric values were within normal ranges. The farmers showed positive responses in precipitin test and test for inhibition of leukocyte migration to antigens of environmental microbes, mainly to the antigen of Gram-negative bacterium Pantoea agglomerans. The results showed a potential risk of occupational respiratory diseases in the population of hops farmers.

Precipitin response of potato processing workers to work-related microbial allergens

Serum samples from 61 potato processing workers and 30 urban dwellers not exposed to organic dusts (as a reference group) were examined in agar-gel precipitation test performed by Ouchterlony double diffusion method with the antigens of 12 microorganisms associated with organic dusts. Each serum was tested twice: not concentrated, and three-fold concentrated, for the detection of low levels of precipitins. The antibody response of workers to the antigen of coryneform bacterium Agromyces ramosus was high, at both not concentrated and 3-fold concentrated sera (respectively 29.5% and 45.9%)--significantly greater than in reference group (p < 0.001). Workers' response to the antigens of Gram-negative bacterium Alcaligenes faecalis and thermophilic actinomycete Thermoactinomyces vulgaris was lower (respectively 13.1% and 13.1% at not concentrated sera, 24.6% and 29.5% at 3-fold concentrated sera) but in all cases significantly greater than in reference group (p < 0.05 at not concentrated sera, p < 0.01 and p < 0.001 at 3-fold concentrated sera). The frequency of positive precipitin reactions of potato workers to antigen of Penicillium citrinum was high only at 3-fold concentrated sera (55.7%)--significantly higher compared to reference group (p < 0.001). The antibody response of potato workers to other antigens was either unspecific or low, showing no significant difference compared to reference group. Twenty eight out of 61 examined potato processing workers (45.9%) reported the occurrence of the work-related pulmonary symptoms. The frequency of positive precipitin reactions to Agromyces ramosus, Alcaligenes faecalis, Thermoactinomyces vulgaris, Penicillium citrinum and Acinetobacter calcoaceticus was significantly greater in the subgroup of 28 workers reporting work-related pulmonary symptoms compared to 33 asymptomatic workers (p < 0.05). Study results suggest that antigens of Agromyces ramosus, Alcaligenes faecalis, Thermoactinomyces vulgaris and Penicillium citrinum should be considered as potential occupational allergens, probably stimulating an adverse immunopathological reaction in the exposed potato processing workers.

The effects of exposure to organic dust on the respiratory system of potato processing workers

A cross-sectional study was carried out to evaluate lung function and the prevalence of work-related symptoms in workers of a potato processing plant located in Lublin region (eastern Poland). The study group comprised 61 workers employed in 2 departments. The examination included: physician-administrated questionnaire on occurrence of work-related symptoms, occupational history and smoking habits. Spirometry was performed before (7:00-8:00) and after (16:00-17:00) the morning shift. Altogether 41/61 (67.2%) subjects reported at least one symptom associated with their job. Pulmonary symptoms were recorded in 28/61 (45.9%) subjects. The most commonly recorded complaints were: cough (44.3%), hoarseness (19.7%), shortness of breath (18%), followed by headache and skin lesion (13.1% each), and eye and nose irritation (11.5%). The prevalence of work-related symptoms (except for eye and nose irritation) was higher in the group of subjects working longer than 4 years (the difference was statistically significant only for skin lesion). Among non-smoking workers a significantly higher prevalence of headache was seen compared to smokers (Fisher's test, p < 0.05). Smokers complained more frequently of respiratory symptoms such as cough, shortness of breath, hoarseness and chest pain. The difference was significant only for cough (p < 0.05). A statistically significant over-shift decline in all measured spirometric values: FVC, FEV(1) (p < 0.001), FEV(1)/VC (p < 0.05), PEF (p < 0.01) was observed.

Work-related symptoms among furniture factory workers in Lublin region (eastern Poland)

48 woodworkers employed in the furniture factory were examined. The control group consisted of 41 office workers with no exposure to organic dust. The examination included: interview on work-related symptoms, physical examination, and lung function test performed before and after the working-day. 38 out of 48 (79.2%) woodworkers reported work-related symptoms. The most common complaint was dry cough reported by 25 workers (52.1%), followed by general malaise -- reported by 17 (35.45%), conjunctivitis -- by 16 (33.3%), rhinitis - by 16 (33.3%), and skin symptoms by 16 (33.3%). Other symptoms such as headache, shortness of breath and chest pain occurred less frequently. Subjects working in initial processing and board processing departments had a higher prevalence of cough compared to workers employed in the varnishing department (p < 0.01). The prevalence of skin symptoms was significantly higher in board processing and varnishing departments compared to initial processing department (p < 0.05). Occupational asthma and allergic alveolitis were recorded in 3 out of 48 (6.2%) and 2 out of 48 (4.2%) workers, respectively. Baseline FVC and FEV(1) values were lower in woodworkers compared to controls (p < 0.01). The increased lung function parameters (FVC, FEV(1)) were observed in woodworkers who smoked compared to non-smokers. The difference was not statistically significant. There was a significant over-shift decrease of all measured spirometric values: FVC, FEV(1)), FEV(1)) /VC, PEF among woodworkers (p < 0.001). There was a significant pre-shift, post-shift decline in FVC, FEV(1)), FVC/FEV(1)), and PEF among workers under 30 years of age (p < 0.001). The same tendency was seen for FVC and FEV(1)) in subjects over 30. The percentage changes in FVC and FEV(1)) were greater in the group of younger workers (15.1% and 17.6%) respectively, than in the group of older subject (6.2%, 7.1%). The difference was not statistically significant.

Response of furniture factory workers to work-related airborne allergens

The aim of this work was to determine the reactivity of furniture factory workers to microbial allergens associated with wood dust. Allergological examinations by skin and precipitin tests were performed in 48 workers employed in a factory producing furniture from fibreboards and chipboards, and in 32 healthy urban dwellers not exposed to organic dusts (referents). The skin test was performed by the intradermal method with the saline extracts of the cultures of 3 microbial species (Rahnella sp., Arthrobacter globiformis, Aspergillus fumigatus) associated with wood dust. Skin reactions were recorded after 20 minutes, 8 hours and 24 hours and graded 1-4, depending on the diameter of the reaction. The agar-gel test for the presence of precipitins in serum was performed with the extracts of 15 microbial isolates. The furniture factory workers showed a high skin response to the extracts of environmental microbes. The frequency of early grade 2 reactions (diameter 10 mm) to the extract of Rahnella sp. was 64.6% among furniture workers, being significantly higher (p < 0.001) compared to reference group (18.7%). High frequencies of grade 2 reactions in furniture workers were also found with the extracts of A. globiformis and A. fumigatus (52.1% and 62.5%, respectively). The frequencies of grade 2 delayed (after 8 h) and late (after 24 h) reactions to Rahnella sp. in furniture workers were non-specifically high (97.9%/93.7%) while the response rates to A. globiformis and A. fumigatus were much lower (10.4%/25.0%, and 4.2%/37.5%, respectively). In agar-gel test for detection of precipitins, in most cases very low percentages of positive reactions (0-2.1%) were noted in furniture factory workers. The only exception was a high percentage of positive reactions (27.1%) to the antigen of Pseudomonas maltophilia, which was significantly greater in furniture workers compared to the reference group (p < 0.01). The obtained results suggest that early allergic reactions to microorganisms associated with wood dust are common among workers of furniture industry, which may increase a potential risk of work-related disease in this occupational group.

Atopy, allergic diseases and work-related symptoms among students of agricultural schools: first results of the Lublin study

136 eastern-Polish farming students (51 females and 85 males, aged 16-23 years) underwent clinical examination, skin prick tests with common and farm-specific allergens, total IgE measurement and Phadiatop test. Atopy was found in 35.3% (95% CI: 27.3-43.3%) of students. For allergic skin diseases, the point prevalence was 5.9%, the lifetime prevalence 28.7%; for allergic rhinitis 12.7% and 16.4%; for asthma 2.2% and 8.8% respectively. 56 students (41.2%) complained of work-related symptoms; most often of pruritus (30.9%), erythema of the skin (16.9%), sneezing (16.2%), rhinorrhea (15.4%), cough (9.6%) and dyspnea (8.1%). The students reported as causative factors of work-related symptoms: grain dust (71.4% of the 56 symptomatic students), hay dust (57.1%), straw dust (17.9%), green parts of plants (5.4%), fertilisers, diesel fuel and farm animals (3.6% each). Prick tests were positive in 30.9% of students, most frequently to Lepidoglyphus destructor (18.4% of all students), Tyrophagus putrescentiae (15.4%), Dermatophagoides pteronyssinus (14.0%), Acarus siro (13.2%) and weed pollens (5.1%). The only statistically significant difference between males and females found in the study was that in the lifetime prevalence of allergic skin diseases (males 17.6% versus females 47.1%, p<0.001). Students reporting work-related symptoms had significantly more present and past allergic skin diseases and allergic rhinitis (for each feature p<0.01), and past obstructive lung disease (p=0.001). In 12 farming students (8.8%, 95% CI: 4.1-13.6%), employment as a farmer was strongly contraindicated due to health status.

Young farmers with cellular reactivity to airborne microbes suffer more frequently from work-related skin symptoms and allergic dermatitis

75 farming students (49 males and 26 females aged 16-23 years) underwent dermatological, laryngological and pulmonary examination, skin prick tests with common and farm allergens, Phadiatop and total IgE measurement. After that, the migration inhibition tests with antigens of airborne microbes typical for farm environment (Saccharopolyspora rectivirgula, Pantoea agglomerans, and Aspergillus fumigatus) were carried out. Possible differences between students with positive results and those non-reactive were sought.

RESULTS

10 students reacted to at least one microbial antigen in the migration inhibition test. There were no significant differences in distribution of atopy, prick test results, total IgE, and Phadiatop between the reactive students and their classmates. Only one case of asthma was found, hence a further statistical analysis was not feasible. Allergic rhinitis has been found in 30% of the reactive and in 9.2% of non-reactive students; the difference, however, was not statistically significant (p=0.06). Significant differences were found with respect to the frequency of allergic skin diseases (40% reactive versus 9.2% non-reactive, p = 0.009); no other triggering factors than microbial antigens could be identified in 2 out of 4 reactive students with dermatitis. Work-related symptoms were present in all reactive students (100% versus 27.7%, p=0.001); 8 out of 10 reactive students did not show any other specific sensitisation. Antigens of airborne microbes are commonly associated with lung diseases. Our results, however, suggest that the skin may be affected as well. Relatively strong association between cellular reactivity to airborne microbes and skin diseases deserves further studies.

Use of intramolecular chimeras to map molecular determinants of symptom severity of potato spindle tuber viroid (PSTVd)

Nucleotide sequence comparison shows that sequence variations are mostly clustered in the P (pathogenicity) and V (variable) domains of the potato spindle tuber viroid (PSTVd) molecule. Although these comparisons suggest the P domain as the primary determinant of PSTVd symptom severity, the potential contribution of the V domain has never been analysed in detail. To investigate the relationship between the structure of these domains and pathogenicity, six intraspecific chimeric PSTVd variants were constructed by exchanging P and V domains between a mild and two different severe PSTVd isolates. Infectivity studies showed that the P domain is directly responsible for the severity of symptoms induced in tomato. The four recombinants containing a P domain from a severe isolate caused severe symptoms including severe epinasty, stunting and veinal necrosis, while the two chimeras containing the mild isolate P domain induced only mild symptoms. Quantitation of viroid accumulation in plants infected with the various recombinants suggests that, with the constructions used, symptom severity did not correlate with viroid accumulation, indicating that the P domain did not influence symptom production through this simple mechanism.

Analysis of the population structure of three phenotypically different PSTVd isolates

Phenotypically dissimilar greenhouse isolates from a Polish collection of potato spindle tuber viroid (PSTVd) were analysed. Partially purified PSTVd genomic RNAs from severe, intermediate and mild isolates was reverse transcribed and the resulting cDNAs enzymatically amplified. Abutting-primer PCR (Ab-P PCR) technology was used to obtain, in a single step, infectious full-length PSTVd cDNA monomers and these were sequenced. The mild isolate was found to be composed of a unique molecular variant (M), closely related to previously described PSTVd mild isolates. In the intermediate isolate, three variants, i2, i3 and i4, were detected. The severe isolate was found to be a mixture containing at least four molecular variants: s23, s27, i4 and i2. Infection of test plants with plasmids carrying monomeric cDNAs corresponding to each of the cloned variants confirmed that they are infectious. In addition, variant M produced mild symptoms, variants i2, i3, i4 intermediate symptoms and variants s23 and s27 severe symptoms. Therefore, the disease symptoms produced by a mixture are determined by the severe variants, masking the presence of milder ones. All the variants detected (except i2 which is identical to previously described PSTVd-DI) represent novel PSTVd sequences with point mutations located in the V and/or P domains. In particular, variants s23 and i4 represent shorter (358 nucleotides) versions of the PSTVd genome.