The Impact of ESCRT on Aβ1-42 Induced Membrane Lesions in a Yeast Model for Alzheimer's Disease

Aβ metabolism plays a pivotal role in Alzheimer’s disease. Here, we used a yeast model to monitor Aβ₄₂ toxicity when entering the secretory pathway and demonstrate that processing in, and exit from the endoplasmic reticulum (ER) is required to unleash the full Aβ₄₂ toxic potential. Consistent with previously reported data, our data suggests that Aβ₄₂ interacts with mitochondria, thereby enhancing formation of reactive oxygen species and eventually leading to cell demise. We used our model to search for genes that modulate this deleterious effect, either by reducing or enhancing Aβ₄₂ toxicity, based on screening of the yeast knockout collection. This revealed a reduced Aβ₄₂ toxicity not only in strains hampered in ER-Golgi traffic and mitochondrial functioning but also in strains lacking genes connected to the cell cycle and the DNA replication stress response. On the other hand, increased Aβ₄₂ toxicity was observed in strains affected in the actin cytoskeleton organization, endocytosis and the formation of multivesicular bodies, including key factors of the ESCRT machinery. Since the latter was shown to be required for the repair of membrane lesions in mammalian systems, we studied this aspect in more detail in our yeast model. Our data demonstrated that Aβ₄₂ heavily disturbed the plasma membrane integrity in a strain lacking the ESCRT-III accessory factor Bro1, a phenotype that came along with a severe growth defect and enhanced loading of lipid droplets. Thus, it appears that also in yeast ESCRT is required for membrane repair, thereby counteracting one of the deleterious effects induced by the expression of Aβ₄₂. Combined, our studies once more validated the use of yeast as a model to investigate fundamental mechanisms underlying the etiology of neurodegenerative disorders.

Recent Insights on Alzheimer's Disease Originating from Yeast Models

In this review article, yeast model-based research advances regarding the role of Amyloid-β (Aβ), Tau and frameshift Ubiquitin UBB+1 in Alzheimer’s disease (AD) are discussed. Despite having limitations with regard to intercellular and cognitive AD aspects, these models have clearly shown their added value as complementary models for the study of the molecular aspects of these proteins, including their interplay with AD-related cellular processes such as mitochondrial dysfunction and altered proteostasis. Moreover, these yeast models have also shown their importance in translational research, e.g., in compound screenings and for AD diagnostics development. In addition to well-established Saccharomyces cerevisiae models, new upcoming Schizosaccharomyces pombe, Candida glabrata and Kluyveromyces lactis yeast models for Aβ and Tau are briefly described. Finally, traditional and more innovative research methodologies, e.g., for studying protein oligomerization/aggregation, are highlighted.

Expression of Leukemia-Associated Nup98 Fusion Proteins Generates an Aberrant Nuclear Envelope Phenotype

Chromosomal translocations involving the nucleoporin NUP98 have been described in several hematopoietic malignancies, in particular acute myeloid leukemia (AML). In the resulting chimeric proteins, Nup98's N-terminal region is fused to the C-terminal region of about 30 different partners, including homeodomain (HD) transcription factors. While transcriptional targets of distinct Nup98 chimeras related to immortalization are relatively well described, little is known about other potential cellular effects of these fusion proteins. By comparing the sub-nuclear localization of a large number of Nup98 fusions with HD and non-HD partners throughout the cell cycle we found that while all Nup98 chimeras were nuclear during interphase, only Nup98-HD fusion proteins exhibited a characteristic speckled appearance. During mitosis, only Nup98-HD fusions were concentrated on chromosomes. Despite the difference in localization, all tested Nup98 chimera provoked morphological alterations in the nuclear envelope (NE), in particular affecting the nuclear lamina and the lamina-associated polypeptide 2α (LAP2α). Importantly, such aberrations were not only observed in transiently transfected HeLa cells but also in mouse bone marrow cells immortalized by Nup98 fusions and in cells derived from leukemia patients harboring Nup98 fusions. Our findings unravel Nup98 fusion-associated NE alterations that may contribute to leukemogenesis.

Rlp24 activates the AAA-ATPase Drg1 to initiate cytoplasmic pre-60S maturation

Formation of eukaryotic ribosomes is driven by energy-consuming enzymes. The AAA-ATPase Drg1 is essential for the release of several shuttling proteins from cytoplasmic pre-60S particles and the loading of late joining proteins. However, its exact role in ribosome biogenesis has been unknown. Here we show that the shuttling protein Rlp24 recruited Drg1 to pre-60S particles and stimulated its ATPase activity. ATP hydrolysis in the second AAA domain of Drg1 was required to release shuttling proteins. In vitro, Drg1 specifically and exclusively extracted Rlp24 from purified pre-60S particles. Rlp24 release required ATP and was promoted by the interaction of Drg1 with the nucleoporin Nup116. Subsequent ATP hydrolysis in the first AAA domain dissociated Drg1 from Rlp24, liberating both proteins for consecutive cycles of activity. Our results show that release of Rlp24 by Drg1 defines a key event in large subunit formation that is a prerequisite for progression of cytoplasmic pre-60S maturation.

The genotoxic risk of hospital, pharmacy and medical personnel occupationally exposed to cytostatic drugs--evaluation by the micronucleus assay

The aim of this study was to evaluate the genotoxicity of cytostatic drugs in hospital and pharmacy employees (n=100), occupationally exposed. The micronucleus assay was used to study lymphocytes in 247 peripheral blood samples. Samples were collected at "baseline level" without any cytostatic drugs exposure before recruiting or after at least 3 weeks without cytostatic drugs contact and at three times (cycle 1-3) post-exposure. Samples from 60 office employees served as controls. Furthermore, our results were compared to urinary analyses of cytostatic drugs (oxazaphosporines, anthracyclines, platinum) which were collected in parallel to the cytogenetic investigation. Statistical analyses were performed under consideration of age, gender and X-ray exposure. The frequency of micronuclei was significantly related to the age of the subjects (r(Spearman)=0.16; P<0.05). However, there were no significant differences in micronucleus rates between controls and exposed hospital workers. Similarly, micronucleus rates were not significantly different at the various sampling time points and there was no correlation between duration of employment and micronucleus rates. Furthermore, no correlation between current biomonitoring data of exposure (urine tests) and micronuclei frequency was found. Therefore, significantly increased genotoxic damage of the lymphocytes investigated in this study could not be demonstrated.

Aerosol bolus dispersion in patients with bronchiolitis obliterans after heart-lung and double-lung transplantation. The Munich Lung Transplantation Group

Bronchiolitis obliterans (BO) is one of the main late complications in patients after lung transplantation. Because BO is located in small airways, conventional lung function tests are supposed to be rather insensitive to detect early stages of this disease. In this study, the capability of the aerosol bolus dispersion test to detect BO was tested in 12 subjects with heart-lung and double-lung transplantation. Four of these patients had histological evidence of BO. The broadening (dispersion) of inhaled boluses consisting of monodispersed inert test particles during respiration was repeatedly measured in each subject. Additional measurements of spirometric and bodyplethysmographic measurements were performed. Patients with evidence of BO showed significantly increased aerosol bolus dispersion and significantly reduced maximal airflow parameters. Calculation of receiver operating characteristics (ROCs) revealed that from all lung function parameters under consideration, aerosol bolus dispersion divided by the maximum expiratory flow rate at 50% of vital capacity (MEF50) and MEI50 had the highest sensitivity and specificity for the detection of BO. Both parameters showed a sensitivity and specificity of 100%. Therefore, it may be speculated that even in early stages of disease, the combination of MEF50 measurement with aerosol bolus dispersion measurements may be a powerful tool for the detection of BO in patients with lung transplantation.

Urinary excretion of platinum from platinum industry workers

OBJECTIVES

Assessment of level of exposure to platinum and platinum concentration in urine from platinum industry workers to evaluate internal exposures and excretion kinetics.

METHODS

Platinum concentrations in urine samples from 34 workers were measured by adsorptive voltammetry after UV-photolysis. Morning and evening samples were taken two to six times during six months. Individual exposures were assessed by personal air sampling. Also, two male volunteers were exposed to platinum dust for four hours at a typical platinum refinery workplace.

RESULTS

Urinary platinum excretion after a shift in platinum industry workers was found to be up to 6270 ng/g creatinine--that is, 1000 times above the median value of unexposed people. Urinary excretion reached the maximum nearly 10 hours after inhalative exposure to dust containing platinum. Elimination corresponded to a first half life of about 50 (95% confidence interval (95% CI) 36 to 66) hours, but there were indications that a part of the incorporated platinum is stored longer. The amount of urinary platinum excretion showed a close correlation with the exposure level monitored by personal air sampling.

CONCLUSIONS

A newly developed analytical method enabled the detection of even natural background concentrations of platinum. Thus, increased urinary platinum concentrations could be detected early, which is important to avoid damaging health of exposed workers.

Occupational asthma in hairdressers: results of inhalation tests with bleaching powder

STUDY OBJECTIVE

To analyze the extent to which the clinical diagnosis of bleach-induced asthma can be confirmed by laboratory tests and to determine the role of work-related exposure to bleaching powder in a group of hairdressers with respiratory complaints.

METHODS

The study population consisted of 55 female hairdressers who had regular contact with various hair products and a clinical history of job-related rhinitic and/or asthmatic symptoms. We divided the individuals into two groups: group I, with asthmatic symptoms (n = 38), and group II, without asthmatic symptoms (control group, n = 17). All subjects underwent immunological, pulmonary-function, and nonspecific bronchial provocation tests, and 46 study participants were subjected to a standardized bleaching-powder test in a designated chamber.

RESULTS

There were 13 positive responses to bleaching powder in the skin test, and 32 individuals showed positive bronchial responsiveness to acetylcholine; positive responses to the challenge with bleaching powder occurred in 9 women (22% of those tested). None of the women in group II reacted to bleaching powder. There was no significant difference between persons with a positive or a negative bronchial provocation test with regard to the evaluated parameters.

CONCLUSIONS

In the diagnostic workup of hairdressers with work-related respiratory symptoms, bleaching powder is one of the products that need to be tested. As not every patient with an asthmatic response to bleaching powder shows a positive response to the acetylcholine challenge test, in doubtful cases a specific exposure test may be recommendable.

Cardiopulmonary exercise testing following hay exposure challenge in farmer's lung

In patients experiencing an acute episode of hypersensitivity pneumonitis (HP), the alveoli and interstitium show a marked inflammation. The effects of this infiltration with effector cells on gas exchange and the cardiopulmonary system are not well characterized, and there are no data regarding cardiopulmonary exercise testing during hypersensitivity pneumonitis. The aim of this study was to gain new insights into the pathophysiology of acute farmer's lung using cardiopulmonary exercise testing. Cardiopulmonary exercise testing was performed in patients who had farmer's lung (n=21) before and 4 h after a standardized exposure with mouldy hay. Farmers who were asymptomatic for this condition (n=15) served as controls. At baseline, patients who had farmer's lung had a decreased breathing reserve and a greater alveolar to arterial oxygen difference. Following exposure, all of these patients developed hypersensitivity pneumonitis. Compared to the asymptomatic farmers, they showed an increase of alveolar to arterial oxygen difference and functional dead space ventilation during exercise and a reduction of the breathing reserve. In addition, 40% of the asymptomatic farmers demonstrated a pathological increase of the alveolar to arterial oxygen difference during exercise following exposure. In conclusion, our data signify that acute hypersensitivity pneumonitis induces significant changes in pulmonary gas exchange during exercise. Cardiopulmonary exercise testing may help to identify individuals with possible subclinical farmer's lung disease.

Biological monitoring of hospital pharmacy personnel occupationally exposed to cytostatic drugs: urinary excretion and cytogenetics studies

For evaluation of the risk borne by hospital pharmacy personnel exposed to antineoplastic agents, the incorporation of cyclophosphamide, ifosfamide, and platinum-containing drugs was quantified by the determination of urinary concentrations. In addition, the induction of micronuclei (MN) and sister-chromatid-exchange (SCE) rates in peripheral blood lymphocytes were studied for correlation with the urinary excretion of cytostatic drugs. Cyclophosphamide and ifosfamide were determined in 24-h urine samples using gas chromatography with electron capture (detection limit 2.5 micrograms/l). Voltammetric analysis enabled the determination of platinum concentrations of 4 ng/l. Heparinized blood (20 ml) was drawn and lymphocytes were cultured for MN and SCE studies. In all, 13 hospital pharmacists and pharmacy technicians regularly involved in the preparation of cytostatic drugs participated in this investigation (7 persons represent a follow-up group). All subjects applied standard safety precautions, including the use of a vertical laminar air-flow hood, protective gowns, and latex gloves. On the day of urine sampling an average of 4,870 mg cyclophosphamide, 5,580 mg ifosfamide, and 504 mg platinum-containing drugs were handled. The excretion of 5 and 9 micrograms cyclophosphamide/l urine was measured in two samples, respectively. An elevated level of urinary platinum was found in one pharmacist (22.3 ng/g creatinine) in comparison with a nonexposed control group. Mean frequencies of MN and SCE did not differ significantly between the drug exposed group and control group. The employees who had incorporated chemotherapeutic agents were part of the follow-up group and, thus, particularly cautious and sensitive to a possible hazard. The results emphasize the necessity of improving personal protection of hospital pharmacy personnel occupationally exposed to cytostatic drugs and support the importance of biological monitoring. In an ongoing project in our department the sources of contamination are being investigated parallel to biological monitoring so as to determine critical situations and improve personal protection.

Long-term augmentation therapy in twenty patients with severe alpha-1-antitrypsin deficiency--three-year follow-up

The purpose of this uncontrolled, prospective study was to evaluate the influence of long-term augmentation therapy with plasma-derived alpha 1-antitrypsin (AAT) on lung function parameters in patients with severe emphysema caused by AAT deficiency. Twenty patients (mean age 48 years) received AAT infusions once weekly for up to 36 months. No adverse effects were observed. At the beginning of the study, mean (+/- SEM) FEV1 was 1.35 +/- 0.12 liters and mean TLCO was 54 +/- 4% of predicted. After 36 months of treatment, mean FEV1 was 1.25 +/- 0.12 liters (p = n.s) and the TLCO was 52 +/- 4% predicted (p = n.s). Similar values were obtained before and after therapy for FVC (2.79 +/- 0.23 vs. 2.82 +/- 0.21 liters), MEF50 (0.72 +/- 0.09 vs. 0.68 +/- 0.08 liters/s), RV (4.60 +/0 0.44 vs 4.45 +/- 0.311) and TLC (7.72 +/- 0.49 vs. 7.38 +/- 0.42 l). The calculated annual loss of FEV1 (35.6 ml/year) was smaller than in historical untreated patients with AAT deficiency.

Cardiorespiratory responses to incremental exercise in patients with systemic sclerosis

Patients with systemic sclerosis are known to have histologic pulmonary abnormalities despite normal chest radiograph or conventional pulmonary function or both. In an attempt to detect early features of lung involvement in progressive systemic sclerosis, we investigated patients with systemic sclerosis using cardiopulmonary exercise testing. We have studied 78 patients who fulfilled the American Rheumatism Association criteria for the classification of systemic sclerosis, and according to the classification of LeRoy, 44 had limited cutaneous systemic sclerosis and 34 had diffuse cutaneous systemic sclerosis. A significantly decreased diffusing capacity (65 +/- 3% of that predicted) was present only in the group with diffuse cutaneous systemic sclerosis. The patients with lung involvement showed a significant reduction in exercise capacity (54 +/- 3% of that predicted) and in oxygen uptake (70 +/- 3% of that predicted). Additionally, we could demonstrate an increased functional dead space ventilation (0.34 +/- 0.02) and widened alveolar-arterial oxygen difference during exercise (44 +/- 3 mm Hg). By cardiopulmonary exercise testing, 12 of the 78 patients (15%) with normal single-breath diffusing capacity for carbon monoxide had increased dead space to tidal volume ratio. Our results suggest that occult pulmonary impairment may be present in patients with normal pulmonary function and that cardiopulmonary exercise testing enables detection of such impairment. Our study results show the limitations of resting data in predicting abnormalities during exercise in patients with systemic sclerosis.

Bronchoalveolar lavage for evaluation and management of scleroderma disease of the lung

Fibrosing alveolitis (FA) is a frequent and often fatal complication of systemic sclerosis (SSC). Alveolar inflammation has been recognized as a primary event in the pulmonary manifestation of SSC. To evaluate the significance of the alveolitis in SSC, we performed bronchoalveolar lavage (BAL) and correlated the generated data with changes in lung function over time. Seventy nine SSC patients with pulmonary involvement were followed for 56.8 +/- 3.1 wk (mean +/- SEM) with a repeat lung function test at the end of the follow-up period. During follow-up, 38 patients were treated with a systemic immunosuppressive regimen. For evaluation, patients were assigned to two groups according to whether their BAL cell differential was normal (inactive BAL) or abnormal (active BAL: i.e., polymorphonuclear leukocytes > 5% and/or lymphocytes > 15%). Active BAL was associated with more severe lung function impairment than was inactive BAL, and patients with active BAL deteriorated during follow-up if untreated. In contrast, treated patients with active BAL stabilized or improved. In summary, active alveolitis as characterized by BAL is associated with progressive pulmonary disease in SSC patients, and a significant positive effect of immunosuppressive therapy on the course of pulmonary disease was observed in patients with active BAL.

Characterization of soybean allergens causing sensitization of occupationally exposed bakers

Fourteen bakers suffering from workplace-related respiratory symptoms and sensitized to soybean were studied. Twelve of them were also allergic to wheat flour, 10 to rye flour, and five to alpha-amylase of Aspergillus oryzae (Asp o 2). IgE estimation by RAST strongly indicated that the trypsin inhibitor and lipoxidase are major allergens of soybean. Various allergenic components could be characterized by immunoblotting after two-dimensional electrophoresis. Our RAST and immunoblotting results show an interindividually different allergic response to inhalative soybean constituents, and that the trypsin inhibitor (20 kDa, pI approximately 4.5) is an important inhalative soybean allergen recognized by IgE antibodies in the sera of 86% of the examined sensitized bakers.

Airborne platinum concentrations in Munich city buses

Airborne platinum concentrations sampled over 4 h in local buses in Munich during regular rides were analyzed by adsorptive stripping voltammetry. The detection limit was 0.5 pg/m3, related to an air-sampling of 5 m3. In 96 samples from 1993 and 1994 we found a mean concentration of 7.3 pg/m3 (S.D. 6.5). The route with highest traffic showed 33.0 pg/m3 compared to 3.0 pg/m3 at a suburban bus route.

Environmental ozone field study on pulmonary and subjective responses of assumed risk groups

Lung function parameters (measured with a body plethysmograph) and subjective votes on irritations of eyes or airways were taken from subjects belonging to four assumed ozone risk groups and one control group (40 subjects each: senior citizens, juvenile asthmatics, forestry workers, athletes, and clerks). Every subject was examined on 8 days both in the morning and in the afternoon. The intention was to obtain an equal distribution of measuring days with elevated and low ozone concentrations, respectively, for each subject. On average the ozone concentrations reached 0.070 ppm on "ozone days" [maximum concentration 0.112 ppm for clerks (outdoors), 0.100 ppm for senior citizens, 0.091 for juvenile asthmatics, 0.086 ppm for athletes, and 0.077 ppm for forestry workers] and 0.028 ppm on "control days" (minimum 0.001 ppm). The results show no relevant ozone effect for the group with the lowest ventilation rate (senior citizens) and only marginal reductions of respiratory flows and volumes for athletes. Pulmonary decrements of juvenile asthmatics on ozone days were small but larger than those documented in the literature for healthy children. Forestry workers and clerks had significantly higher airway resistances on ozone days, although having been exposed to the lowest ozone concentrations of all groups. Thus, on days with moderately elevated levels of ozone in the environment it is assumed that ozone itself has a minor influence on pulmonary responses compared to that of other constituents of the air in certain locations like in forests or indoors on these days. These could be reaction products of ozone with motor tool exhausts in the case of forestry workers or substances originating from ozone deposition on the surfaces of the offices.

[Lung function and prevalence of irritation of eyes and respiratory airways on days with elevated ozone concentrations]

In order to evaluate potential health effects on days with elevated ozone concentrations, lung function parameters and subjective votes on irritations of eyes and airways were taken repeatedly from subjects belonging to four assumed ozone risk groups and one control group (at least 40 subjects each) - senior citizens, juvenile asthmatics, forestry workers, athletes and clerks - in comparison of days with elevated (at least 100 micrograms/m3) and low ozone concentrations (at most 80 micrograms/m3). The results show no relevant ozone effects for the groups, "senior citizens" and "athletes", only minor pulmonary effects for "juvenile asthmatics", but significantly higher airway resistances on "ozone days" for "forestry workers" (by 21%) and "clerks" (by 16%). On days with moderately elevated levels of ozone in the environment it is assumed that ozone itself has minor influence on pulmonary responses compared to that of other constituents of the air in certain location like forest or indoors.

Increased oxidation of extracellular glutathione by bronchoalveolar inflammatory cells in diffuse fibrosing alveolitis

An unbalanced oxidative stress is thought to be an important element in the pathogenesis of diffuse fibrosing alveolitis (DFA). The purpose of our study was to investigate the role of reactive oxygen metabolites (ROMs) released from cultured bronchoalveolar inflammatory cells (BA-cells) on glutathione oxidation. We studied bronchoalveolar lavage samples from 10 healthy controls and from 20 patients with diffuse fibrosing alveolitis (all were nonsmokers). BA-cells obtained by bronchoalveolar lavage (BAL) were incubated with 50 microM of reduced glutathione (GSH). Oxidation of GSH to glutathione disulphide (GSSG) by BA-cell derived oxidants was detected as a decline of GSH in the supernatants. Total glutathione (GSHtot = GSH + 2 GSSG) and GSSG in the epithelial lining fluid (ELF), and methionine sulphoxide (Met(O)) content of BAL proteins were determined. In diffuse fibrosing alveolitis the oxidative activity of BA-cells was enhanced, GSHtot and GSH were decreased, whereas the GSSG:GSH ratio was increased. The oxidative activity of BA-cells correlated positively with the GSSG:GSH ratio, but not with the methionine sulphoxide content. The methionine sulphoxide content was elevated in diffuse fibrosing alveolitis and inversely correlated with GSHtot. The methionine sulphoxide content also correlated positively with the percentage of BAL neutrophils. We conclude that BA-cell-derived reactive oxygen species are capable of oxidizing extracellular GSH in vitro. The positive correlation between the BA-cell oxidative activity in vitro and GSSG:GSH ratio in ELF suggests that a similar oxidative effect on extracellular GSH may also occur in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pulmonary manifestations of systemic scleroderma: pathophysiologic and clinical significance of the activation of lung fibroblasts]

Fibrosing alveolitis (FA) is a common and often fatal complication of systemic sclerosis (SSC). The purpose of this study was to characterize the fibrotic process within the lungs using bronchoalveolar lavage fluid (BALF). We investigated 25 healthy controls (CON) and 85 SSC patients. In 61 patients (72%) lung function tests, clinical, and radiological findings indicated manifest FA, whereas 24 patients (28%) where free of significant lung disease. Of the latter, 12 had pathologic BAL differential cell counts (= subclinical alveolitis; SUB), 12 had normal BAL cytology (NOR). BAL samples were analysed for chemoattractant activity (CAA) for fibroblasts using Boyden chambers. Procollagen-III-Peptide (P-III-P) and Laminin fragment P1 (Lam-P1) were measured radioimmunologically. CAA (expressed as % of the effect of conditioned medium) was increased in FA and SUB (CON: 17.3 +/- 3.2; FA: 40.8 +/- 5.8, p < 0.01 vs. CON; SUB: 58.6 +/- 11.8, p < 0.01 vs. CON; NOR: 23.7 +/- 6.3; n.s.). Lam-P1 [U/ml ELF] was also elevated in FA and SUB patients (CON: 0.90 +/- 0.17; FA: 2.07 +/- 0.48, p < 0.05 vs. CON; SUB: 2.61 +/- 1.14, p < 0.05 vs. CON; NOR: 1.05 +/- 0.35, n.s. vs. CON). P-III-P [U/ml ELF] was elevated in FA patients (CON: 8.3 +/- 1.1; FA: 26.9 +/- 5.5, p < 0.001 vs. CON) but not in SUB or NOR (SUB: 10.2 +/- 0.7, NOR: 7.9 +/- 2.9; n.s.). There was no significant relationship between P-III-P and LAM-P1 values in ELF and serum, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenetic and clinical significance of fibroblast activation in scleroderma lung disease

Fibrosing alveolitis (FA) is a major and often fatal complication of systemic sclerosis (SSC). The critical role of fibroblasts in the pathogenesis of FA has long been recognized. Characterization of fibroblast activation in the lungs may improve our understanding and the management of this disease. We analyzed bronchoalveolar lavage (BAL) fluid samples from 9 healthy controls and 43 patients with FA caused by lung involvement form SSC. The chemoattractant activity (CAA) of cultured human fibroblasts elicited by native BAL fluid was measured in Boyden chambers. In addition, procollagen III peptide was measured in BAL fluid as a marker of collagen synthesis. CAA (expressed as percentage of the chemoattractant effect of 0.25 ng/ml platelet-derived growth factor; PDGF) was elevated in the SSC patients compared with that of the controls (control: 12.6 +/- 4.0%; SSC: 68.8 +/- 15.2%; p < 0.01). A positive correlation was found between BAL total cell count and CAA (r = 0.60, p < 0.01). An inverse correlation existed between CAA and total lung capacity (r = -0.55, p < 0.05). The patients were followed up for 13.3 +/- 1.4 months (mean +/- SEM). Twenty-seven patients received immunosuppressive therapy, whereas 16 refused therapy. The patients were assigned to two groups according to their CAA being lower or higher than 36% of the PDGF response (= mean value of the controls + 2 SD).

Respiratory and other hazards of isocyanates

Isocyanates are increasingly being used for manufacturing polyurethane foam, elastomers, adhesives, paints, coatings, insecticides, and many other products. At present, they are regarded as one of the main causes of occupational asthma. The large number of workers who are exposed to these chemicals have a concentration-dependent risk of developing chronic airway disorders, especially bronchial asthma. Different pathophysiologic mechanisms are involved. Immunoglobulin E (IgE)-mediated sensitization and irritative effects have been clearly demonstrated in both exposed subjects and animals. Presumably, neural inflammation due to neuropeptide release of capsaicin-sensitive afferent nerves is crucial. We collected data on 1780 isocyanate workers who had been examined by our groups. Of them 1095 (including subjects from outpatient departments) had work-related symptoms, predominantly of the respiratory tract. Specific IgE antibodies were found in 14% of the 1095 subjects. The methacholine challenge test was shown to be an inadequate predictor of the results of inhalative isocyanate provocation tests in workers and in asthmatic controls. Isocyanate (toluene diisocyanate TDI) air concentrations of 10 ppb (0.07 mg/m3) and 20 ppb (0.14 mg/m3), respectively, did not cause significant bronchial obstruction in the majority of previously unexposed asthmatics with bronchial hyperreactivity. IgG-mediated allergic alveolitis, a rare disease among isocyanate workers, was found in approximately 1% of the symptomatic subjects. Experimental studies exhibit dose-dependent toxic effects and give evidence for tachykinin-mediated bronchial hyperreactivity after exposure to isocyanates. The clinical role of genotoxic effects of isocyanates and their by-products demonstrated here in vitro and in vivo has yet to be clarified.

Allergens causing bird fancier's asthma

The study investigates to what extent bird feathers contain relevant allergens/antigens involved in bird fancier's asthma. The study group consisted of two budgerigar fanciers, two parrot fanciers and one canary fancier. All subjects complained of asthmatic symptoms, caused by contact with their birds, and they showed a significant bronchial hyperreactivity to acetylcholine. Positive IgE antibody reactions to bird sera as well as to extracts of feathers were observed in RAST. Well-defined major allergenic bands could be detected and identified in the IgE immunoblots with feather extracts as well as with serum proteins of budgerigar, parrot, pigeon, canary, and hen (mol. mass 20-30 kDa and 67 kDa). The most pronounced bands appeared with the extracts of species to which an exposure had taken place. Weaker IgG-binding patterns were also observed. Our results show that inhalable feather dust contains several allergenic components which cross-react with serum allergens/antigens of the same as well as of other bird species. This emphasizes the significance of bird feathers for immediate-type allergic reactions.

Biological monitoring of cyclophosphamide and ifosfamide in urine of hospital personnel occupationally exposed to cytostatic drugs

The occupational exposure of 21 nurses and pharmacy personnel from eight hospitals to cyclophosphamide and ifosfamide was determined by quantifying the amount of the drugs handled and by measuring the urinary excretion of the unmetabolised substances. Preparing antineoplastic drugs for intravenous treatment was the major task of all study participants. Twenty four hour urine was collected on days when cyclophosphamide and/or ifosfamide were mixed, on average 3900 mg cyclophosphamide and/or 5900 mg ifosfamide. The analyses were performed by gas chromatography with electron capture, detection limit 2.5 micrograms/24 hour urine. Despite standard safety precautions, including a vertical laminar air flow safety cabinet and gloves, cyclophosphamide was detected in 12 of 31 and ifosfamide in four of 21 urine samples on days when the drugs were handled. Excretion of cyclophosphamide ranged from 3.5 to 38 micrograms/24 h (mean 11.4 micrograms/24 h) urine, ifosfamide from 5 to 12.7 micrograms/24 h (mean 9 micrograms/24 h) urine. Based on an excretion rate of 11.3% unmetabolised cyclophosphamide, the average amount excreted corresponded to an uptake of 101 micrograms cyclophosphamide. For ifosfamide the mean quantity incorporated was 20 micrograms assuming that 45% of the drug was excreted. Pertaining to the doses handled, the uptake of cyclophosphamide and ifosfamide was estimated to be approximately 0.0025% and 0.0004% respectively. Despite time-consuming purification procedures, gas chromatographic analysis is a suitable method for monitoring personnel occupationally exposed to cyclophosphamide and ifosfamide and is a major contribution to the evaluation of potential health risks of exposed personnel.

Urinary platinum in hospital personnel occupationally exposed to platinum-containing antineoplastic drugs

Urinary platinum levels of 21 nurses and hospital pharmacy personnel occupationally exposed to platinum containing antineoplastic drugs were determined in 24-h urine by voltammetric analysis after UV photolysis. All study participants applied standard safety measures, including a vertical laminar air-flow cabinet and latex gloves. The amount of platinum-containing drugs prepared for intravenous application ranged from 40-3260 mg/day. Urinary platinum was detected in 9 of 52 urine samples collected on days when platinum-containing drugs were mixed (limit of determination 4 ng/l). In comparison with a non-exposed control group, elevated urinary platinum levels were found in one pharmacist (35 ng/g creatinine) and one pharmacy technician (28 ng/g creatinine). The pharmacist's urinary platinum remained elevated after 2 days without occupational exposure to antineoplastic drugs. The urinary platinum level of the pharmacy technician dropped considerably after several weeks without handling cytostatic drugs. Voltammetric detection of urinary platinum is a highly sensitive method suitable for biological and environmental monitoring.

Activation of blood neutrophils in acute episodes of farmer's lung

Farmer's lung often presents clinically as recurring acute episodes several hours after exposure to moldy hay. During these episodes the blood neutrophil count increases. Because activated neutrophils release toxic oxygen metabolites and proteinases, we hypothesized that the pulmonary reaction in farmer's lung may be induced by the secretory products of activated neutrophils. To evaluate this concept, we quantified the respiratory burst of separated blood neutrophils from patients with farmer's lung (n = 12) during standardized exposure tests with moldy hay. The respiratory burst of these cells was evaluated by measuring zymosan-stimulated and lucigenin-amplified chemiluminescence (CL). Asymptomatic farmers (n = 12) and normal volunteers with no prior exposure to moldy hay (n = 15) were used as control subjects. As expected, following exposure in the group of patients with farmer's lung, striking changes in VC, TLCO, and PaO2 were observed, whereas there were only minor changes in these parameters in both control groups. In all three groups a considerable increase in the blood leukocyte count was observed. The CL response of the blood neutrophils from patients with farmer's lung 6 h after exposure was significantly higher than before or 1 h after exposure (p < 0.05 for both comparisons), whereas there was no significant change in the CL response in either control group during the observation period. Our results indicate that antigen inhalation induces an increase in the number of circulating neutrophils in patients and controls, but in patients with an acute episode of farmer's lung the neutrophils are primed for an enhanced respiratory burst and may thereby damage the lung.

Fibroblast chemotactic response elicited by native bronchoalveolar lavage fluid from patients with fibrosing alveolitis

BACKGROUND

In fibrosing alveolitis activation of lung fibroblasts is the decisive event in the pathogenetic sequence leading to pulmonary fibrosis. Fibroblast stimulating activity was measured in bronchoalveolar lavage (BAL) fluid to assess its relationship to the activity of fibrosing alveolitis.

METHODS

Nine control subjects and 40 patients with fibrosing alveolitis caused by idiopathic pulmonary fibrosis (n = 22) or pulmonary involvement in systemic sclerosis (n = 18) were studied. All patients were followed up by lung function testing for a minimum of six months (mean (SE) 13.3 (1.4) months). Twenty five patients received immunosuppressive therapy and 15 refused. At the beginning of follow up BAL was performed and, as a possible indicator of fibroblast stimulating mediators within the lungs, chemotactic migration of cultured human fibroblasts elicited by native BAL fluid was measured in Boyden-type chambers and expressed as a percentage of the chemoattractant effect of 25 ng/ml platelet derived growth factor. The procollagen III peptide level in BAL fluid served as a marker for collagen synthesis.

RESULTS

Chemoattractant activity was elevated in the patients with idiopathic pulmonary fibrosis and systemic sclerosis compared with the control group, (mean (SE) 56.4% (8.5%)) and 72.3% (16.3%) v 12.6% (4.0%). Chemoattractant activity was inversely correlated with total lung capacity (TLC) (r = -0.45) and with vital capacity (VC) (r = -0.33). Procollagen III peptide concentrations in BAL fluid and chemoattractant activity were not significantly correlated. For further evaluation chemoattractant activity of 36% (mean value of controls +2 SD) was used to separate normal (< 36%) from elevated (> or = 36%) activity. At the end of follow up, untreated patients with high chemoattractant activity (> or = 36%) showed a significant reduction of VC, TLC, and exercise arterial oxygen tension (PaO2) and a small decrease in carbon monoxide transfer factor (TLCO), whereas a significant improvement in VC, TLC, and TLCO and a small increase of exercise PaO2 occurred in treated patients with high chemoattractant activity. Patients with low chemoattractant activity (< 36%) showed no consistent change in lung function measurements, irrespective of treatment. In contrast, lung function results and differential cell counts in BAL fluid failed to identify progressive disease.

CONCLUSIONS

In patients with fibrosing alveolitis the chemoattractant activity of BAL fluid seems to be an independent indicator of lung fibroblast stimulating activity providing relevant information about disease activity, and may help to improve the clinical management of these patients.

Nocturnal asthma. Beta 2-adrenoceptors on peripheral mononuclear leukocytes, cAMP- and cortisol-plasma concentrations

To evaluate pathophysiologic mechanisms of the predominantly nocturnal complaints in atopic bronchial asthma, the expression and function of beta 2-adrenoceptors on peripheral mononuclear leukocytes (pMNL), the cAMP--as well as the cortisol--plasma concentrations were studied in eight healthy men and ten so far untreated male asthmatic patients at 4-h intervals for 24 h. No difference was seen in the beta 2-adrenoceptor density (Bmax) on pMNL between healthy and asthmatic men (24-h means +/- SE: 908 +/- 59 sites per cell and 821 +/- 54 sites per cell, respectively). The equilibrium dissociation constant (Kd), however, was significantly higher in the asthmatic patients (24-h mean +/- SE: 8.8 +/- 1.2 pmol/L vs 3.0 +/- 0.2 pmol/L in healthy men, p less than 0.0001), which is equivalent to a lower affinity of the beta 2-adrenoceptors for the radioligand 125iodocyanopindolol. Bmax showed a statistically significant circadian variation, but Kd did not. The circadian variation in Bmax was reflected in the basal intracellular cyclic adenosine-monophosphate (cAMP) content of the cells investigated. High Kd values (equivalent to low receptor affinities) tended to be associated with small increases of the intracellular cAMP content after in vitro stimulation by 10(-7) mol/L isoprenaline (isoproterenol) (24-h mean +/- SE: 1.4 +/- 0.2 pmol/10(6) cells; r = -0.529, p = 0.05 at r = -0.549, n = 10). Plasma cAMP concentrations were found to be significantly lower in the asthmatic patients (24-h means +/- SE: 22.9 +/- 1.3 nmol/L vs 29.1 +/- 1.1 nmol/L, p less than 0.0001). Plasma cortisol concentrations were significantly higher in the asthmatic patients (24-h means +/- SE: 0.500 +/- 0.084 mumol/L vs 0.319 +/- 0.063 mumol/L). The results support the hypothesis that a lesion of the beta-adrenergic system contributes to the pathophysiology of atopic bronchial asthma. In the patients investigated in this study, such a lesion could be demonstrated in the affinity rather than in the number of beta 2-adrenoceptors expressed on peripheral cells of the immune system (pMNL). According to present-day knowledge of adrenergic effects on pMNL, such an affinity decrease of beta 2-adrenoceptors could account for overshooting immune responses. In association with other factors influencing respiratory function, it could be responsible for the predominantly nocturnal complaints in atopic bronchial asthma. Plasma cortisol concentrations did not appear to be related to the principal cause of "nocturnal asthma;" they rather reflected an endogenous defense mechanism to the disease.

[Diagnosis of humidifier lung--comparison of various serologic procedures]

Humidifier lung is a form of exogenous-allergic alveolitis caused by microbial growth in humidifiers and air conditioners. It was the aim of the present study to employ and test the ELISA method as an alternative to antibody determination. 134 employees in a large printhouse equipped with air conditioning plant were examined by us. Specific IgG antibodies against contaminated humidifier fluid were determined by means of a solid-phase radioimmunoassay (protein A RAST) that we had developed further. Alternatively we examined a commercially available ELISA method (Pharmacia IgG-RAST 40; enzyme: beta-galactosidase) and an assay based on protein A peroxidase. The influence of different test conditions was studied. All the methods examined proved suitable for determining the specific IgG antibodies. The commercial beta-galactosidase assay could be adapted to application on microtitre plates in a slightly modified form. In the peroxidase assay it is recommended to use very low serum and enzyme concentrations on account of its high sensitivity. Examination of all the 134 serum samples yielded a high correlation between the results of these two non-radioactive methods and those obtained with the protein-A RAST.

Isocyanate-induced asthma: results of inhalation tests with TDI, MDI and methacholine

We performed diisocyanate inhalation tests (maximal concentration, 20 ppb; exposure time, 1-2 h) using toluene diisocyanate (TDI, n = 15) and diphenylmethane diisocyanate (MDI, n = 7) as well as methacholine challenges in 19 workers who had a clinical history of TDI/MDI-induced asthma. Additionally we tested volunteers who had no previous contact with diisocyanates: 10 healthy individuals with a negative methacholine test and 14 patients with asthma and a positive methacholine test were exposed to TDI. In all, 1 of the normal volunteers and 3 of the patients with asthma unrelated to diisocyanates showed a positive airway reaction to TDI, and 13 of the 19 diisocyanate workers displayed a positive result in the TDI/MDI inhalation test; however, only 6 of these 13 individuals reacted to methacholine. Furthermore, 3 of the 6 patients with a negative TDI/MDI challenge test demonstrated a significant response to methacholine. We conclude that bronchial hyperreactivity as evaluated by the methacholine challenge test is not closely related to isocyanate-induced bronchoconstriction and, therefore, the metacholine challenge is only of limited diagnostic value in patients with suspected isocyanate-induced asthma.

[Correlation of parameters of the flow-volume curve for the assessment of bronchial hyperreactivity]

The association of maximal expiratory flow-volume curve and the response of nonspecific bronchial responsiveness was studied in 265 normal and asthmatic subjects. Bronchial hyperresponsiveness to acetylcholine was found in 143 subjects. These hyperreactive persons had already significantly reduced maximal expiratory flow rate at 75%, 50% and 25% vital capacity before the test started. Besides, we found a significant correlation between the provocative dose and the flow-volume parameters, although resistance was in the normal range. We concluded that the flow rates at middle and low lung volumes may be an important determinant of bronchial sensitivity to acetylcholine.

Beta 2-adrenoceptors in human lung and peripheral mononuclear leukocytes of untreated and terbutaline-treated patients

Beta 2-adrenoceptor agonists act against bronchoconstriction by stimulating beta 2-adrenoceptors in bronchial smooth muscle. However, tachyphylaxis has been argued to occur because of beta 2-adrenoceptor down-regulation following therapy with beta 2-adrenergic agents. To investigate receptor alterations, human peripheral mononuclear leukocytes are frequently used, since human lung tissue is not easily available. In order to study whether beta 2-adrenoceptors in MNL reliably reflect the conditions in the human lung tissue, we compared MNL and human lung tissue of 18 patients who had to undergo lung resection. Ten patients were untreated, and eight had bronchodilator therapy prior to therapy with terbutaline because of bronchoconstriction. Both in human lung and MNL, the beta 2-adrenoceptor subpopulation was characterized by competition experiments with the beta 1-selective antagonist CGP 207.12 A and the beta 2-selective antagonist ICI 118.551. In MNL, a significant decrease in the density of beta 2-adrenoceptors was found in treated but not in untreated patients, while the antagonist affinity of the beta 2-adrenoceptors remained unchanged. However, in lung parenchyma, which was obtained at the very same time from the same patients, no down-regulation of the total amount of beta 2-adrenoceptors could be measured. It is concluded that MNLs are a reliable model for studying properties of beta 2-adrenoceptor regulation. However, the hereby obtained results show that MNLs do not reflect the conditions of beta 2-adrenoceptors in human lung tissue. Human lung tissue is found to be less susceptible than human MNL for beta 2-adrenoceptor down-regulation by terbutaline treatment at therapeutic doses.(ABSTRACT TRUNCATED AT 250 WORDS)

[Bronchial asthma in a hairdresser caused by hair bleach]

Three years after starting to work as a hairdresser a 33-year-old woman developed urticaria on contact with hairbleach. After a further four years rhinoconjunctivitis set in and later also bronchial asthma on contact with such bleaches. Extensive tests revealed hypersensitivity to widely used persulphate-containing bleaching liquids which ultimately forced the patient to give up her profession. The causative role of this group of chemicals was proven by positive skin tests and specific workplace-related provocation tests. But specific IgE antibodies could not be demonstrated. The findings suggest a pseudoallergic reaction.

[Diagnosis of irritative-toxic isocyanate asthma with the isocyanate exposure test]

We investigated 10 healthy control subjects, 15 asthmatics without occupational exposure to isocyanate, and 45 "isocyanate workers" with workplace-related respiratory symptoms. In none of the cases did the skin test or the IgE-RAST reveal a type I sensitisation to isocyanate. The investigation programme included a lung function test, provocation with metacholine or acetylcholine, and an isocyanate challenge test under controlled clinical conditions. A total of 17 "isocyanate workers", and 1 asthma patient with no occupational exposure to isocyanate revealed a positive bronchial obstructive reaction to the isocyanate challenge test. In 10 of the patients, the MCH (ACH) test was positive; 2 were chronically obstructive, but 6 patients showed no signs of bronchial hyperreactivity. No significant differences in the severity of the bronchial obstructive reaction induced by isocyanate exposure were observed between patients with and those without bronchial hyperreactivity. In the group of "isocyanate workers", the isocyanate challenge test was observed to be superior to the MCH (ACH) provocation test in terms of sensitivity (0.68 versus 0.62) and specificity (1.0 versus 0.61), this difference being more obvious in the overall group (sensitivity 0.71 versus 0.62; specificity 0.98 versus 0.49).

Tuberous sclerosis with pulmonary involvement

Pulmonary involvement in tuberous sclerosis (pTS) is very rare and seems to be associated with a more benign course, compared to tuberous sclerosis without pulmonary manifestation (TS). Furthermore, pTS seems to be related to lymphangiomyomatosis (LAM). We present the case of a 33-year-old woman in whom the overlap of TS, pTS and LAM is demonstrated. Treatment with medroxyprogesterone was initiated, but without success.

Humidifier lung and humidifier fever

The aim of our study was to evaluate clinical diagnoses in symptomatic persons exposed to aerosols from humidifiers or air conditioners. In addition, we tried to identify the causative antigens. Results of clinical investigations, including inhalation challenge tests, demonstrated a typical hypersensitivity pneumonitis (humidifier lung) in 9 persons and isolated systemic symptoms without significant changes in lung function and chest x-rays (humidifier fever) in 3 persons. Microbiological studies revealed a variety of fungi and bacteria in the water supplies of humidifiers and air conditioners at patients' workplaces. The detection of 4 members of the order Sphaeropsidales (Deuteromycotina), not previously associated with humidifier-induced diseases, is of special interest. By means of an improved polystyrene tube-immunoradiometric assay, high concentrations of IgG antibodies against extracts prepared from water of patients' humidifier systems were found in all cases. In addition, patients demonstrated low concentrations of IgG antibodies against thermophilic Actinomycetes, and usually also against various fungi, such as Alternaria tenuis, Aureobasidium pullulans, Penicillium notatum, Aspergilli, and fungi of the order Sphaeropsidales, which were isolated and cultured from humidifier water supplies. The much higher concentrations of antibodies against humidifier/air conditioner water extracts seem to result from sensitization to a variety of antigens from different fungi and bacteria. For in vivo and in vitro diagnostic tests in humidifier-induced lung diseases, we especially recommend using extracts from water systems installed at the corresponding workplaces.

[Baking ingredients as a contributory cause of baker's asthma]

140 bakers with occupation-related asthma symptoms and/or rhinoconjunctivitis were tested for specific IgE antibodies against various enzyme-containing baking components. 5-24% of subjects were sensitive to several carbohydrate-splitting enzymes obtained from mould fungi (amyloglucosidase, hemicellulase and alpha-amylase), as well as/or against soya flour. But allergies against the proteolytic enzymes papain and B. subtilis protease were rare (about 1%). These results indicate that various baking components, especially mould enzymes, play a not insignificant role in the causation of baker's asthma.