Acute health effects of desktop 3D printing (fused deposition modeling) using acrylonitrile butadiene styrene and polylactic acid materials: An experimental exposure study in human volunteers

3D printers are increasingly run at home. Nanoparticle emissions from those printers have been reported, which raises the question whether adverse health effects from ultrafine particles (UFP) can be elicited by 3D printers. We exposed 26 healthy adults in a single-blinded, randomized, cross-over design to emissions of a desktop 3D printer using fused deposition modeling (FDM) for 1 hour (high UFP-emitting acrylonitrile butadiene styrene [ABS] vs low-emitting polylactic acid [PLA]). Before and after exposures, cytokines (IL-1β, IL-6, TNF-α, INF-γ) and ECP in nasal secretions, exhaled nitric oxide (FeNO), urinary 8-isoprostaglandin F_2α (8-iso PGF_2α ), and self-reported symptoms were assessed. The exposures had no significant differential effect on 8-iso PGF_2α and nasal biomarkers. However, there was a difference (P < .05) in the time course of FeNO, with higher levels after ABS exposure. Moreover, indisposition and odor nuisance were increased for ABS exposure. These data suggest that 1 hour of exposure to 3D printer emissions had no acute effect on inflammatory markers in nasal secretions and urine. The slight relative increase in FeNO after ABS printing compared to PLA might be due to eosinophilic inflammation from inhaled UFP particles. This possibility should be investigated in further studies using additional biomarkers and longer observation periods.

Psychological and cognitive effects of laser printer emissions: A controlled exposure study

The possible impact of ultrafine particles from laser printers on human health is controversially discussed although there are persons reporting substantial symptoms in relation to these emissions. A randomized, single-blinded, cross-over experimental design with two exposure conditions (high-level and low-level exposure) was conducted with 23 healthy subjects, 14 subjects with mild asthma, and 15 persons reporting symptoms associated with laser printer emissions. To separate physiological and psychological effects, a secondary physiologically based categorization of susceptibility to particle effects was used. In line with results from physiological and biochemical assessments, we found no coherent, differential, or clinically relevant effects of different exposure conditions on subjective complaints and cognitive performance in terms of attention, short-term memory, and psychomotor performance. However, results regarding the psychological characteristics of participants and their situational perception confirm differences between the participants groups: Subjects reporting symptoms associated with laser printer emissions showed a higher psychological susceptibility for adverse reactions in line with previous results on persons with multiple chemical sensitivity or idiopathic environmental intolerance. In conclusion, acute psychological and cognitive effects of laser printer emissions were small and could be attributed only to different participant groups but not to differences in exposure conditions in terms of particle number concentrations.

Health effects of laser printer emissions: a controlled exposure study

Ultrafine particles emitted from laser printers are suspected to elicit adverse health effects. We performed 75-minute exposures to emissions of laser printing devices (LPDs) in a standardized, randomized, cross-over manner in 23 healthy subjects, 14 mild, stable asthmatics, and 15 persons reporting symptoms associated with LPD emissions. Low-level exposures (LLE) ranged at the particle background (3000 cm^-3 ) and high-level exposures (HLE) at 100 000 cm^-3 . Examinations before and after exposures included spirometry, body plethysmography, transfer factors for CO and NO (TLCO, TLNO), bronchial and alveolar NO, cytokines in serum and nasal secretions (IL-1β, IL-5, IL-6, IL-8, GM-CSF, IFNγ, TNFα), serum ECP, and IgE. Across all participants, no statistically significant changes occurred for lung mechanics and NO. There was a decrease in volume-related TLNO that was more pronounced in HLE, but the difference to LLE was not significant. ECP and IgE increased in the same way after exposures. Nasal IL-6 showed a higher increase after LLE. There was no coherent pattern regarding the responses in the participant subgroups or single sets of variables. In conclusion, the experimental acute responses to short but very high-level LPD exposures were small and did not indicate clinically relevant effects compared to low particle number concentrations.

Cisplatin and oxaliplatin surface contamination in intensive care units (ICUs) and hospital wards during attendance of HIPEC patients

PURPOSE

The aim of this pilot study was to evaluate surface contamination by platinum drugs in the environment of patients in ICUs and wards treated by hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

The monitoring included 12 HIPEC treatments from four hospitals during the following 3 days after perfusion. A total of 33 urine and 33 drainage fluids from HIPEC patients and 160 wipe samples from several surfaces (urine/drainage bags, floors, gloves) were taken during the study period.

RESULTS

In urine, the highest platinum concentrations were measured on the first day after perfusion. Median platinum concentrations were 1260 ng/ml for patients after cisplatin perfusion and 11,000 ng/ml for oxaliplatin treatment. Concentrations decreased until day three to 413 ng/ml cisplatin and 529 ng/ml oxaliplatin, respectively. In drainage liquids, platinum concentrations were generally lower. Platinum concentrations from surfaces of bags and floors ranged from 0.01 to 439 pg/cm(2) (median: urine bag 2.77 pg/cm(2), drainage bag 0.22 pg/cm(2), floor left 0.14 pg/cm(2), floor right 0.24 pg/cm(2)), with the highest contamination found on the outer surface of the urine bags. Samples from nurses' protective gloves ranged between 0.03 and 12 pg/cm(2) (median: 0.2 pg/cm(2)).

CONCLUSIONS

High platinum-drug concentrations in urine and drainage liquids are the main source of contamination. Therefore, safe handling of these liquids is the best way to avoid cross-contamination on surfaces in wards and ICUs. Our results show that it is possible to take care of HIPEC patients without high contaminations during the first 3 days.

Cow hair allergen concentrations in dairy farms with automatic and conventional milking systems: From stable to bedroom

Bovine hair and dander are considered to be a notable risk factor for sensitization and allergic symptoms in occupationally exposed cattle farmers due to various IgE binding proteins. Farmers are suspected not only to be exposed during their work inside the stables but also inside their homes as allergens could be transferred via hair and clothes resulting in continued bovine allergen exposure in private areas. In recent years a new sensitive sandwich ELISA (enzyme linked immunosorbent assay) test has been developed to measure the cow hair allergen (CHA) concentration in dust. The aim of the present study was to determine the CHA concentration in airborne and settled dust samples in stables and private rooms of dairy cattle farms with automatic milking systems (AM) and conventional milking systems (CM), also with respect to questionnaire data on farming characteristics. For this purpose different sampling techniques were applied, and results and practicability of the techniques were compared. Dust sampling was performed in the stable, computer room (only AM), changing room, living room and bedroom (mattress) of 12 dairy farms with automatic milking systems (AM group) and eight dairy farms with conventional milking systems (CM group). Altogether, 90 samples were taken by ALK filter dust collectors from all locations, while 32 samples were collected by an ion charging device (ICD) and 24 samples by an electronic dust fall collector (EDC) in computer rooms (AM) and/or changing and living rooms (not stables). The dust samples were extracted and analyzed for CHA content with a sandwich ELISA. At all investigated locations, CHA concentrations were above the limit of detection (LOD) of 0.1 ng/ml dust extract. The median CHA concentrations in dust collected by ALK filters ranged from 63 to 7154 μg/g dust in AM farms and from 121 to 5627 μg/g dust in CM farms with a steep concentration gradient from stables to bedrooms. ICD sampling revealed median CHA contents of 112 μg/g airborne dust in the computer rooms of the AM farms and median CHA loads of 5.6 μg/g (AM farms) and 19.8 μg/g (CM farms) in the living rooms. Passive dust sampling by EDC was performed only at two locations in the AM group resulting in median CHA values of 116 μg/m(2) (computer room) and 55.0 μg/m(2) (changing room). Except for the stable samples the median CHA load was lower in AM farms compared to CM farms. The CHA contents of ALK filter samples were significantly correlated in most locations. Differences between the farming types were not significant. Although allergen transfer to the private area of the farmers has been found and results from several locations were correlated, differences in CHA concentrations were not significant with respect to questionnaire data such as the wearing of stable clothes in living room, free access of pets to stable and home, frequency of hair washing. All sampling techniques seem to being practicable for simple and effective CHA measurement.

Levels of Cr, Co, Ni and Mo in erythrocytes, serum and urine after hip resurfacing arthroplasty

BACKGROUND

Hip resurfacing arthroplasty is known to increase the metal ion concentration in the serum, urine and whole blood, with potentially adverse effects on the organism. However, only few data are available about the metal ion concentrations in erythrocytes, although they are directly exposed to the higher concentrations of the serum.

METHODS

The ion levels of chromium, cobalt, nickel and molybdenum in erythrocytes of 25 patients with a hip resurfacing implant were analysed with high resolution ICP-sf-MS (inductively-coupled-plasma-sector-field-mass-spectrometry). The results were compared to the ion levels in the serum and urine of the patients, and also to the ion levels of 27 control persons without an implant.

RESULTS

Compared to the control group, ion levels in the erythrocytes of the hip resurfacing group were markedly increased for cobalt (0.10 vs. 3.26 microg/kg) and slightly for chromium (6.04 vs. 7.38 microg/kg). In contrast, ion levels in the serum of the hip resurfacing group were increased for cobalt (0.21 vs. 1.92 microg/l), chromium (1.48 vs. 5.64 microg/l), nickel (1.53 vs. 4.25 microg/l) and molybdenum (2.17 vs. 3.78 microg/l).

CONCLUSION

Ion concentrations of cobalt and chromium are also increased in erythrocytes after hip resurfacing arthroplasty. Further research is required to evaluate the impact of the elevated ion levels on the erythrocytes, and to evaluate if metal ions also accumulate in other tissues of the body.

Toxicity and elemental composition of particulate matter from outdoor and indoor air of elementary schools in Munich, Germany

Outdoor particulate matter (PM(10)) is associated with detrimental health effects. However, individual PM(10) exposure occurs mostly indoors. We therefore compared the toxic effects of classroom, outdoor, and residential PM(10). Indoor and outdoor PM(10) was collected from six schools in Munich during teaching hours and in six homes. Particles were analyzed by scanning electron microscopy and X-ray spectroscopy (EDX). Toxicity was evaluated in human primary keratinocytes, lung epithelial cells and after metabolic activation by several human cytochromes P450. We found that PM(10) concentrations during teaching hours were 5.6-times higher than outdoors (117 ± 48 μg/m(3) vs. 21 ± 15 μg/m(3), P < 0.001). Compared to outdoors, indoor PM contained more silicate (36% of particle number), organic (29%, probably originating from human skin), and Ca-carbonate particles (12%, probably originating from paper). Outdoor PM contained more Ca-sulfate particles (38%). Indoor PM at 6 μg/cm(2) (10 μg/ml) caused toxicity in keratinocytes and in cells expressing CYP2B6 and CYP3A4. Toxicity by CYP2B6 was abolished with the reactive oxygen species scavenger N-acetylcysteine. We concluded that outdoor PM(10) and indoor PM(10) from homes were devoid of toxicity. Indoor PM(10) was elevated, chemically different and toxicologically more active than outdoor PM(10). Whether the effects translate into a significant health risk needs to be determined. Until then, we suggest better ventilation as a sensible option.

PRACTICAL IMPLICATIONS

Indoor air PM(10) on an equal weight base is toxicologically more active than outdoor PM(10). In addition, indoor PM(10) concentrations are about six times higher than outdoor air. Thus, ventilation of classrooms with outdoor air will improve air quality and is likely to provide a health benefit. It is also easier than cleaning PM(10) from indoor air, which has proven to be tedious.

Low surface contamination by cis/oxaliplatin during hyperthermic intraperitoneal chemotherapy (HIPEC)

AIM

The aim of this study was to evaluate contamination by platinum drugs in the operating room during hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

Environmental sampling of 151 wipe samples from surfaces on the HIPEC devices and operating room floors was performed for platinum in six German hospitals during 19 HIPEC procedures. Additionally, 45 wipe samples from surgeons' and perfusionists' protective gloves were analyzed.

RESULTS

Platinum concentrations from the HIPEC devices and operating room floors ranged from 0.07 to 110,000 pg/cm(2) (Median: 1.5 pg/cm(2)) with high contamination on the regulation knob and reservoir after HIPEC procedure, particularly when injecting the cytostatic drug into the reservoir via syringe. Samples from perfusionists' and surgeons' protective gloves ranged between 0.01 and 729 ng/pair.

CONCLUSIONS

Although sporadically high platinum concentrations on surfaces on the HIPEC device and operating room floor were detected, our study revealed that low surface loads are definitely possible and can be documented by wipe samples. Important factors for achieving low surface contamination are the use of infusion bags instead of syringes for injection of the cytostatic solution, careful cleaning of the device after HIPEC and wearing of two pairs of gloves.

Serum leptin and adiponectin levels and their association with allergic sensitization

BACKGROUND

Obesity and respiratory allergies have increased in parallel in industrialized countries. We have recently shown an association between obesity and allergic sensitization whereby obesity diminished the protective effect of childhood farm contact.

OBJECTIVE

To assess whether taking obesity into account allergic sensitization is associated with adipokine levels in blood and whether this effect is modified by childhood farm contact.

METHODS

Serum samples of 231 adult participants (age 18-45 years) of the Lower Saxony Lung Study were analysed for leptin and adiponectin by ELISA. Subjects were elected to represent equal-sized groups with respect to obesity (<30 vs> or =30 kg/m(2)), childhood farm contact, specific IgE to ubiquitous allergens and sex. Multiple logistic regression models were adjusted for potential confounders.

RESULTS

Leptin levels were positively related to the prevalence of sensitization (highest vs lowest quartile odds ratio 6.7, 95% confidence interval 2.0-22.4). For adiponectin levels, a weak, not statistically significant inverse association with sensitization was shown (highest vs lowest quartile 0.4, 0.2-1.1). The association between leptin and sensitization appeared to be more pronounced in subjects with farm contact; however, the effect modification was not statistically significant.

CONCLUSION

These findings suggest that adipokines might be involved in the causal pathway between obesity and allergic sensitization.

[Air quality in schools - classroom levels of carbon dioxide (CO2), volatile organic compounds (VOC), aldehydes, endotoxins and cat allergen]

Children are assumed to be more vulnerable to health hazards and spend a large part of their time in schools. To assess the exposure situation in this microenvironment, we evaluated the indoor air quality in winter 2004/5 in 92 classrooms, and in 75 classrooms in summer 2005 in south Bavaria, Germany. Indoor air climate parameters (temperature, relative humidity), carbon dioxide (CO2) and various volatile organic compounds, aldehydes and ketones were measured. Additionally, cat allergen (Fel d1) and endotoxin (LAL-test) were analysed in the settled dust of school rooms. Data on room and building characteristics were collected by use of a standardised form. Only data collected during teaching hours were considered in analysis. The median indoor CO2 concentration in the classrooms ranged in the winter and summer period from 598 to 4 172 ppm and 480 to 1 875 ppm, respectively. While during the winter period in 92% of the classrooms the CO2 daily medians went above 1 000 ppm, the percentage of classrooms with increased CO2 concentration fell to 28% in summer. In winter, in 60% of classes the daily median CO2 concentration exceeded 1 500 ppm, while in summer this threshold was reached by only 9%. A high concentration of CO2 was associated with a high number of pupils, a low room surface area and a low room volume. The levels of total volatile organic compounds (TVOC) in classrooms ranged between 110 and 1 000 microg/m3 (median in winter 345 microg/m3, in summer 260 microg/m3). Acetone, formaldehyde and acetaldehyde were measured in concentrations from 14.0 to 911 microg/m3, from 3.1 to 46.1 microg/m3, and from 2.9 to 78 microg/m3, respectively. The other aldehydes were detected in minor amounts only. The median Fel d1 level in winter was 485 ng/g dust (20 to 45 160 ng/g) and in summer it was 417 ng/g (40-7 470 ng/g). We observed no marked differences between the two sampling periods and between smooth floors and rooms with carpeted floors. No differences were found according to room surface area and room volume. The median endotoxin contents in winter and summer were 19.7 EU/mg dust (6.6 to 154 EU/mg) and 32.2 EU/mg (9.6 to 219 EU/mg), respectively. The levels varied significantly between the sampling periods, but were independent of room surface area, room volume and surface floorings. Overall the results of VOC, aldehydes, ketones and endotoxin indicate, in general, a low exposure level in classrooms. The observed concentrations of cat allergens should be considered as a meaningful exposure route and thus could be tackled within preventive programs.

Heart rate variability, hemostatic and acute inflammatory blood parameters in healthy adults after short-term exposure to welding fume

The present study aimed to investigate, whether short-term experimental exposure to high levels of welding fumes would be capable of exerting acute effects in healthy subjects. Specifically, we assessed cardiovascular function in terms of heart rate variability (HRV) as well as the concentrations of inflammatory mediators and hemostatic proteins in blood as outcome measures. Twenty subjects without a history of airway and cardiovascular diseases were exposed to either control air or welding fume for 1 h on 2 separate days under standardized conditions. The median concentration of the alveolar particle fraction during welding was 3.5 mg/m(3 )(quartiles: 1.4-6.3 mg/m(3); range 1.0-25.3 mg/m(3)). Five hours later a panel of clinical assessments was performed, including HRV measurement and drawing of blood samples. There were no changes in symptom ratings or lung function after welding fume exposure. Exposures did also not differ regarding effects on time- and frequency-domain parameters of HRV. Similarly, blood leukocyte numbers, cell differentials and the blood levels of fibrinogen, C-reactive protein, antithrombin III, factor VIII, von Willebrand factor, ristocetin cofactor, sICAM-1, tumor necrosis factor alpha, interleukin 6, interleukin 8 and epithelial neutrophil activating peptide 78 were not altered by welding fume inhalation. However, there was a significant fall in the level of endothelin-1 (P < 0.01). In conclusion, the data did not indicate effects of clinical significance of a short-term high-level exposure to welding fumes on HRV or a set of blood hemostatic and acute inflammatory parameters in healthy subjects. The small but statistically significant effect on endothelin levels demonstrated that measurable effects could be elicited even in these individuals. Overall, welding fumes are not likely to exert acute cardiovascular effects in healthy individuals.

Exposure to pets, and the association with hay fever, asthma, and atopic sensitization in rural children

BACKGROUND

An increasing number of studies report pet exposure to be associated with lower risk of asthma and allergies. This 'protective pet effect' has been suggested to result from a modified T-helper (Th)2-cell response, or because of increased microbial load in homes where pets are kept. We examined the associations between pet contact and the occurrence of asthma and allergies in children of the rural Allergy and Endotoxin (ALEX) population, taking farm animal contact, endotoxin and cat allergen levels in mattress dust into account.

METHODS

Information about contact with pets and farm animals, asthma and allergy were collected for 812 children by a standardized parents' questionnaire and an interview. Mattress dust endotoxin and cat allergen levels as well as specific IgE and IgG4 antibodies to Fel d1 were determined.

RESULTS

Current contact with dogs was inversely associated with diagnosed hay fever (OR 0.26, 95% CI 0.11-0.57), diagnosed asthma (OR 0.29, 95% CI 0.12-0.71), sensitization to cat allergen (OR 0.48, 95% CI 0.23-0.99) and to grass pollen (OR 0.55, 95% CI 0.33-0.94), but not with increased IgG4 levels. Early and current contact with cats were associated with reduced risk of wheezing (OR 0.48, 95% CI 0.23-1.00, and OR 0.49, 95% CI 0.26-0.92, respectively) and grass pollen sensitization. Adjustment for farm animal contact but not for endotoxin and cat allergen exposure attenuated these associations and the effect of pet was stronger among farmers' children.

CONCLUSION

Although pet exposure was very frequent in this rural population, the inverse relation between current dog contact, asthma and allergy was mostly explained by simultaneously occurring exposure to stable animals or was restricted to farm children. In addition, a subtle form of pet avoidance may contribute to the protective effect of pet.

Determinants of endotoxin levels in living environments of farmers' children and their peers from rural areas

BACKGROUND

Lower frequencies of asthma and hayfever have been observed in children with contact to livestock. At school age, the amount of endotoxin measured in the dust of children's mattresses is inversely related to the occurrence of atopic asthma, hayfever and atopic sensitization both in children from farming and non-farming households.

OBJECTIVE

The aim of the present study was to investigate which home and lifestyle characteristics of farm and non-farm families contribute to endotoxin levels measured in different indoor home environments.

METHODS

In the framework of the Allergy and Endotoxin (ALEX) Study, endotoxin was measured in dust samples from the living room floor and the child's mattress of 319 farmers' families and 493 non-farming families, and in settled dust from stables. Endotoxin content of all dust samples was determined by a kinetic Limulus assay (Limulus-Amebocyte-Lysate test). Information about the child's activities on farms, home characteristics and cleaning behaviours was obtained from parental questionnaires.

RESULTS

Endotoxin levels in stables did not predict the amount of endotoxin measured in floors or mattresses. However, a dose-dependent association between the child's activity on the farm and indoor home endotoxin levels was observed, both in farm and non-farm children. In non-farm children pet keeping and the frequency of floor cleaning were additionally associated with endotoxin levels, whereas in farm children parental farm activities, study area, time since last cleaning, the mattress type as well as younger age of the children contributed to increased microbial exposure.

CONCLUSION

These results demonstrate that regular contact to farm animals increases indoor home endotoxin concentrations, both in farm and non-farm children, and might thus explain the protective effect of contact to livestock on atopic outcomes. To assess children's individual exposure to a microbial environment, measures of mattress dust exposure are needed as stable endotoxin concentrations were not associated with indoor home levels.

Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey

BACKGROUND

A farming environment protects against development of asthma, hay fever, and atopic sensitisation in children. We aimed to establish whether increased exposure to microbial compounds has to occur early in life to affect maturation of the immune system and thereby reduces risk for development of allergic diseases.

METHODS

We did a cross-sectional survey in rural areas of Austria, Germany, and Switzerland. 2618 (75%) of 3504 parents of 6-13-year-old children completed a standardised questionnaire on asthma, hay fever, and atopic eczema. Children from farming families, and a random sample of non-farmers' children, who gave consent for blood samples to be obtained for measurements of specific serum IgE antibodies to common allergens were invited to participate (n=901).

FINDINGS

Exposure of children younger than 1 year, compared with those aged 1-5 years, to stables and consumption of farm milk was associated with lower frequencies of asthma (1% [3/218] vs 11% [15/138]), hay fever (3% [7] vs 13% [18]), and atopic sensitisation (12% [27] vs 29% [40]). Protection against development of asthma was independent from effect on atopic sensitisation. Continual long-term exposure to stables until age 5 years was associated with the lowest frequencies of asthma (0.8% [1/122]), hay fever (0.8% [1]), and atopic sensitisation (8.2% [10]).

INTERPRETATION

Long-term and early-life exposure to stables and farm milk induces a strong protective effect against development of asthma, hay fever, and atopic sensitisation.

Urinary platinum levels associated with dental gold alloys

Platinum concentrations were determined in 50 urine and 20 saliva samples obtained from 50 subjects who had gold dental restorations. In addition, 42 urine and 35 saliva samples were collected from subjects who did not have gold dental restorations. Subjects with gold alloys had significantly (p < .001) higher urinary platinum excretion (mean = 11.9 +/- 8.5 ng/gm creatinine, range = 1.9-45.8 ng/gm creatinine) than controls (mean = 6.2 +/- 3.2 ng/gm, range = 1.9-14.4 ng/gm creatinine). Mean saliva concentrations were significantly higher in subjects with dental gold alloys (526 pg/gm vs. 8.5 pg/gm; p < .001). A laboratory test with 5 commercially available dental gold/platinum alloys showed that 0.1% sodium chloride mobilized platinum within 1 hr (i.e., 1-18 pg/ml) of its introduction. In conclusion, dental gold/platinum alloys appear to be the main source for urinary platinum excretion from the occupationally unexposed population.

Urinary excretion of platinum in chemotherapy-treated long-term survivors of testicular cancer

As the majority of patients with metastatic testicular cancer are cured by cisplatin-based chemotherapy and can expect an additional life span of around 50 years, late toxicity is of particular relevance. Urine and serum concentrations of platinum were determined by voltammetry in 37 patients at 5.3 to 16.8 years after cisplatin-based chemotherapy. Urinary excretion and serum levels of platinum were 100 to 1000 times higher in patients than in unexposed controls. There may be an association between platinum storage and endocrinologic and metabolic late sequelae, as well as a risk of second cancer. However, further research is necessary to clarify the biological relevance of long-term storage of platinum.

Exposure to endotoxin or other bacterial components might protect against the development of atopy

BACKGROUND

Several recent studies have shown that growing up on a farm confers significant protection against the development of atopy. These findings point particularly towards the importance of exposure to stable dust and farm animals. It has furthermore been reported that endotoxin, an intrinsic part of the outer membrane of gram negative bacteria, is abundant in environments where livestock and poultry is kept. The aim of this study was therefore to measure the level of environmental endotoxin exposure in homes of farmers' children, children with regular contact to livestock and control children with no contact to farm animals.

METHODS

Eighty-four farming and nonfarming families were identified in rural areas in Southern Germany and Switzerland. Samples of settled and airborne dust were collected in stables, and of settled dust indoors from kitchen floors and the children's mattresses. Endotoxin concentrations were determined by a kinetic Limulus assay.

RESULTS

Endotoxin concentrations were highest in stables of farming families, but were also significantly higher indoors in dust from kitchen floors (143 EU/mg vs 39 EU/mg, P < 0.001) and children's mattresses (49479 EU/m2 vs 9383 EU/m2, P < 0.001) as compared to control children from nonfarming families. In addition, endotoxin levels were also significantly higher in mattresses and dust from kitchen floors in households where children had regular contact to farm animals (38.6 EU/mg and 23340 EU/m2, respectively) as compared to control subjects.

CONCLUSION

We propose that the level of environmental exposure to endotoxin and other bacterial wall components is an important protective determinant for the development of atopic diseases in childhood.

Dust exposure in Munich public transportation: a comprehensive 4-year survey in buses and trams

OBJECTIVES

Published data obtained from outdoor stationary sampling stations cannot be applied directly to the exposure situation in vehicles. The aim of this study, therefore, was to assess the dust exposure relevant to passengers and drivers in public buses and trams.

METHOD

In the years 1993 to 1996, PM10 samples were taken during 201 journeys of typically 4 h duration on 14 routes (nine bus routes, five tramways) which were representative for the overall Munich transportation system with respect to area characteristics and traffic density. The concentrations of the samples were compared with those collected at the same time at sampling stations of the Bavarian State Office for Environmental Protection (OEP). Dust exposure was continuously and synchronously recorded by means of a tyndallometric device. Traffic and passenger density, weather conditions, special events, etc. were noted by our personnel, travelling on every journey.

RESULTS

The average PM10 dust concentration for all rides was 155 microg/m3 (single journey max. 686 microg/m3, min. 13 microg/m3). Interior concentrations were 1.7 to 4.0 times above those collected at the static outdoor stations. We found only minor associations between dust concentrations and traffic density or time of day. During several journeys continuous recording disclosed anomalies, dependence on weather conditions and cyclic track characteristics.

CONCLUSIONS

Interior PM10 particulate concentrations were comparable to those found elsewhere in truck drivers' cabs and are in the region of German regulative limits established for the general population's long term outdoor exposure. Indoor concentrations were well above the values found at stationary outdoor stations. Additional continuous recording of dust concentrations proved to be helpful in unveiling anomalies and dependencies on external effectors.

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.

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.

Cisplatin based chemotherapy in testicular cancer patients: long term platinum excretion and clinical effects

Patients with advanced testicular cancer (TC) have a very good long-term prognosis owing to cisplatin-based polychemotherapy. Platinum is believed to be excreted at a rapid rate via urine within weeks after chemotherapy. As a new, highly sensitive method has become available detecting even natural background platinum levels in body fluids, this study was set up to analyze urinary and serum platinum levels in long-term survivors of testicular neoplasm after cisplatin based polychemotherapy and to correlate clinical data with urinary and serum platinum levels. Urinary platinum concentrations were measured in 64 healthy controls (C) and 22 male patients (TC) 150 to 3022 days after the last application of i.v. cisplatin using voltammetry after UV-photolysis. In the latter group (TC), serum platinum levels were measured as well. Clinical data were analysed as to long-term organ toxicity. Mean urinary platinum levels were 2700 times higher in the patient group (TC) than natural background noise (p < 0.0001). There was a decline of urinary and serum platinum levels over time, being significantly above normal even 8 years after cisplatin exposure. The only significant variables related to the urine platinum concentration were a) the interval between the last i.v. cisplatin application and time of study and b) the total dose given. Not significant were the number of chemotherapy cycles, pre-therapy renal disease, patient age, tumour resection before/after chemotherapy, site of pre/post therapy resection, clinical staging, histological subtypes or tumour markers. Post-therapy renal disease or peripheral nerve damage were not significantly associated with urinary platinum levels. Our data indicate that even 8 years after cisplatin based chemotherapy 500 times elevated urinary and serum platinum levels can be measured in testicular cancer patients. No organ toxicity related to long-term platinum excretion could be detected. This may be due to our small sample size.

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.

Long-term platinum excretion in patients treated with cisplatin

The purpose of this study was to determine long-term renal platinum excretion after chemotherapy with cisplatin. We examined urinary platinum concentrations in 23 men at 150-3022 days after anticancer treatment for testicular neoplasm. Spot urine samples were analyzed by voltammetry. This new, subtle method with a detection limit of 2 pg platinum allows determination of even the natural background level. Urinary platinum concentrations in our patients ranged between 0.74 and 77.24 micrograms/g creatinine, depending on the total delivered dose and follow-up period. Regression analysis of the data showed two phases of long-term renal platinum excretion, one occurring at between 150 and 900 days of follow-up and the other with an onset at 900 days after cisplatin administration (r1(2) = 0.82, r2(2) = 0.88). Two biological half-lives of 160 and 720 days were calculated. Our results show that urinary platinum concentrations determined at 8 years after cisplatin therapy are 40 times higher than the background level (up to 0.02 micrograms/g creatinine). Our findings on the long-term pharmacokinetics of this anticancer agent may facilitate further studies on sites of platinum storage in the human body as well as clinical studies on the late adverse effects of cisplatin.

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.

Dependence of induction of enterobacterial AmpC beta-lactamase on cell-wall peptidoglycan, as demonstrated in Proteus mirabilis and its wall-less protoplast L-form

The mobilizable plasmid pMD101 (ampR, ampC) was constructed by inserting cloned ampC, the structural gene for the chromosomal AmpC beta-lactamase of Citrobacter freundii, and the closely linked ampR encoding the transcriptional regulator essential for enzyme induction, into the broad host-range plasmid pKT231. Plasmid pMD101 was transconjugated into Proteus mirabilis VI and its isogenic, cell-wall-less protoplast L-form LVI. AmpC beta-lactamase was expressed constitutively from cloned ampR and ampC in bacteria and in some L-form protoplasts. However, induction of the enzyme by beta-lactam antibiotics occurred only in bacterial cells and not in the cell-wall- and peptidoglycan-deficient L-form. In agreement with current models, induction of AmpC beta-lactamase is thought to be initiated by an induction signal arising from the metabolic disturbance of cell-wall peptidoglycan.

Interception and retention of Chernobyl-derived 134Cs, 137Cs and 106Ru in a spruce stand

The time dependence of the specific activity of Chernobyl-derived 134Cs, 137Cs and 106Ru was determined in vegetation and soil samples from an old spruce stand within a period of 600 days after the beginning of the radioactive fallout. The results show that 70% of the total activity of radiocesium and 60% of radioruthenium deposited in the spruce stand were retained initially in the canopy. They were removed from the needles and twigs as a result of weathering (rain, wind, litter fall) and transferred to the forest floor, but only rather slowly (half-lives in the canopy: radiocesium, 90 days for the period 0-130 days, 230 days for the period 130-600 days; radioruthenium, 95 days for the period 0-200 days). The transfer of radiocesium and ruthenium to the forest floor by litter-fall was small when compared with that of weathering by rain or wind (radiocesium 7%, radioruthenium 8%, with respect to the total activity deposited in the canopy). The total deposition of radiocesium and ruthenium in the spruce stand was higher by 20 and 24%, respectively, than that observed in nearby grassland. The deposition velocity of radiocesium in the spruce stand was estimated at 5.5 mm s-1, higher by a factor of 10 than the figure for grassland. Similar values were found for radioruthenium.