Pyrethroids used indoor-ambient monitoring of pyrethroids following a pest control operation.

House dust and airborne particles (PM) were sampled before (T1) and 1 day (T2), 4-6 months (T3) as well as 10-12 months (T4) after a pest control operation (PCO). Cyfluthrin was applied in 11, cypermethrin in 1, deltamethrin in three and permethrin in four interiors. The pyrethroid concentrations in house dust and PM were measured by GC/MS with a detection limit for all pyrethroids of 0.5 mg/kg house dust and of 1 ng/m3 PM for deltamethrin and permethrin and 3 ng/m3 PM for cyfluthrin and cypermethrin. A general background concentration of permethrin (95th percentile: 5.9 mg/kg) and cyfluthrin (95th percentile: 34.9 mg/kg) in house dust was found. In general, an appropriately performed PCO lead to an increase of pyrethroids in house dust as well as in PM, in some cases up to 1 year after application. One day after the application the cyfluthrin concentration increased significantly from 0.25 (T1) to 33.8 mg/kg house dust (T2) and up to 4.9 ng/m3 in PM. The permethrin concentration increased significantly from 4.3 to 70 mg/kg in house dust and up to 18.1 ng/m3 in PM, deltamethrin increased to 54.5 mg/kg and 20.8 ng/m3 and cypermethrin to 14 mg/kg and 45.7 ng/m3. Thereafter a continuous decrease could be observed during the time course of 1 year. After 1 year the permethrin concentration in house dust was still 1/5 of the T2 concentration, whereas for cypermethrin and cyfluthrin only 1/14 and 1/23 of the T2 concentration were found. Deltamethrin was not detected at all after T2. Moreover, the data of this study showed significant, positive correlations between pyrethroids in house dust and in airborne particles especially one day after PCO.

Acute stress effects on local Il-1beta responses to pathogens in a human in vivo model.

The combined effects of stress and antigen on interleukin-1beta (Il-1beta) have rarely been studied locally at the site of microbial challenges in vivo, so far. We here propose a model for the analysis of such effects in humans and examine its utility for acute stress trials. Twelve students (6 male, 6 female) refrained from oral hygiene in two antagonistic quadrants for 28 days to allow for increasing bacterial stimulation of the respective gingival sites due to accumulation of microbial plaque. Good oral hygiene was maintained in the remaining quadrants. At day 27 and 28 students were subjected to either stress ('public speech') or a control condition, in a cross-over design. Samples of gingival crevicular fluid (GCF) which emerges between the tooth surface and the gingival epithelium as transudate of healthy and exudate of inflamed gingival tissue, were taken immediately after stress and 60 min later for Il-1beta analysis. Salivary cortisol was assessed to prove the validity of the stress protocol. Stress induced a profound increase of salivary cortisol (p=.001). Repeated measures (stress x time x hygiene) ANOVA with gender as between factor revealed significant stress (p=.014) and hygiene (p=.038) effects on GCF-Il-1beta concentrations and tentatively significant hygiene x time (p = .097) and stress x time x hygiene x gender (p=.107) interactions. Stress induced an increase of Il-1beta as did plaque accumulation. The merits of the proposed model are discussed. It is concluded that it is well suited for the assessment of the effects of stress on inflammatory responses in vivo in humans.

Dietary intake of lead by children and adults from Germany measured by the duplicate method.

The dietary lead intake was studied among children and adults from Germany. Two different age groups of children (A: 1.8, 1.3-3.0 years, B: 3.8, 1.8-5.2 years) and one group of adults (D: 40.9, 24-64 years) were from the highly industrialized Ruhr district and one group of children from the North Sea island Amrum (C: 3.9, 1.5-5.3 years). A total of 229 duplicate food portions were collected from 49 individuals between December 1994 and May 1995. Sampling period for each participant was either 3 (groups B and D) or 7 days (groups A and C). Lead levels in duplicate samples were measured by electrothermal atomic absorption spectrometry. The lead intakes (median, range) for the different groups were as follows: Group A: 0.21 (0.05-1.5) microgram/(kg bw.day), group B: 0.68 (0.06-1.6) microgram/(kg bw.day), group C: 0.29 (0.04-1.6) microgram/(kg bw.day) and group D: 0.26 (0.07-0.83) microgram/(kg bw.day). No value exceeded the provisional tolerable weekly intake (PTWI) of 25 micrograms/(kg bw.week) proposed by the WHO. The median and maximum of the different groups amounted to 7.2-16% and 16-36% of the PTWI, respectively. It is concluded that health risks due to dietary lead intake seem to be low in Germany.

Pyrethroids used indoors--biological monitoring of exposure to pyrethroids following an indoor pest control operation.

A prospective epidemiological study with respect to pyrethroid exposure was carried out combining clinical examination, indoor monitoring and biological monitoring. The results of the biological monitoring are presented. Biological monitoring was performed in 57 persons before (T1) as well as 1 day (T2), 3 days (T3), 4-6 months (T4), and 10-12 months (T5) following a pest control operation (PCO) with pyrethroid containing products such as cyfluthrin, cypermethrin, deltamethrin or permethrin. Pyrethroids in blood were measured by GC-ECD. The respective metabolities cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (DBCA), 3-phenoxybenzoic acid (3-PBA) and fluorophenoxybenzoic acid (FPBA) were measured in urine using GC/MS. For all cases the concentrations of pyrethroids in blood were found to be below the detection limit of 5 micrograms/l before and after the PCO. With a detection limit of 0.2 microgram/l of the investigated metabolites, the percentage of positive samples were 7% for cis-DCCA, 3.5% for trans-DCCA and 5.3% for 3-PBA before PCO. One day after PCO (T2) the percentage of positive samples increased remarkably for cis-DCCA (21.5%), trans-DCCA (32.1%) and 3-PBA (25%) showing significantly increased internal doses as compared to pre-existing values. This holds also true for T3, whereas at T4 and T5 the significant increase was no more present. FPBA and DBCA concentrations were below the respective detection limit before PCO and also in most cases after PCO. In 72% of the subjects the route of pyrethroid uptake (measured by determining the DCCA isomeric ratio) was oral/inhalative and in 28% it was dermal. Based on the biological monitoring data it could be shown that appropriately performed pest control operations lead to a significant increase of pyrethroid metabolite concentration in the early phase (1 and 3 days) after pyrethroid application as compared to the pre-exposure values. However, evaluated metabolite concentrations 4-6 months after PCO did not exceed values of published background levels.

Pyrethroids used indoors--immune status of humans exposed to pyrethroids following a pest control operation--a one year follow-up study.

A multiparametric analysis of immune components was performed in blood and serum of 61 voluntary persons before and after (1 day, 3 days, 4-6 months, 10-12 months) a professional pest control operation (PCO) using pyrethroids. Following parameters were included in the study (1) immunological parameters of the humoral defence, i.e. immunoglobulins of the classes A, G, M and E, complement components C3c and C4, acute phase proteins such as acid alpha 1-glycoprotein, haptoglobin, C-reactive protein; (2) mediators and receptors of immunity, i.e. neopterin, soluble interleukin-2 receptor (sIL-2R), soluble interleukin-6 receptor (sIL-6R), soluble tumor necrosis factor receptor (sTNF RII); (3) immunological markers of the cellular defence, i.e. white blood cell counts and lymphocyte (sub)populations such as total lymphocytes (CD2), mature lymphocytes (CD3), T-helper/inducer cells (CD4), T-suppressor/cytotoxic cells (CD8), B-cells (CD20), natural killer cells (CD56), as well as the ratio of CD4/CD8. The medians of all investigated immune components found before and for all time intervals after pyrethroid application were within the reference interval with respect to the total collective. Within this physiological range the investigated parameters showed a trend to lower values predominantly during the early phase (1 and 3 days) after PCO, partially being significant. Significant decreases were no more present in the late phase (6 to 12 month) after PCO indicating reversibility. Atopics did not differ in the immune response after PCO as compared to non-atopics. Obtained results suggest a modulation of immune components after a correct performed PCO within the physiological range towards lower values during the first days. However these immune changes are considered to be subtle and underlying compensatory mechanisms of immunoregulation.

Hemolytic activity of crystalline silica--separated erythrocytes versus whole blood.

Whole blood and 1% erythrocyte suspensions were treated with crystalline silica (quartz DQ12, Min-U-Sil5) at concentrations of 0.5, 1, 2, and 5 mg/ml. Quartz DQ12 and Min-U-Sil5 revealed a strong dose-dependent hemolytic activity in the 1% erythrocyte suspension reaching nearly total hemolysis (> 80%) at the highest tested concentration of 5 mg/ml. This effect may be ascribed to surface reactivity by silanol groups. In contrast, using whole blood cultures the tested silica dusts caused no or only minor hemolytic activity (< 4%). The mechanism by which the hemolytic activity is prevented in whole blood cultures can be attributed to a number of factors such as the presence of metal binding proteins and free radical scavenger, antioxidant mechanisms and to coating of the silica surface by proteins, antibodies and complement. In contrast to separated erythrocytes whole blood represents an independent physiological compartment with functions of host defence and regulatory functions against cell damaging effects produced by oxidative stress.

Effects of plaque, psychological stress and gender on crevicular Il-1beta and Il-1ra secretion.

OBJECTIVES: The study aimed to analyse (a) whether the effects of psychological stress and of experimental gingivitis on interleukin-1beta (Il-1beta) described before are compensated by concomitant increases in Il-1 receptor antagonist (Il-1ra), and (b) whether there do exist any gender differences in the Il-1 responses to experimental gingivitis and to psychological stress. MATERIALS AND METHODS: Thirteen medical students participating in a major academic exam (seven males, six females) and 14 medical students without academic stress (eight males, six females) refrained from oral hygiene in two antagonistic quadrants for 28 days (plaque) while they maintained oral hygiene in the remaining quadrants (hygiene). Weekly crevicular fluid samples of plaque and hygiene sites were assayed for Il-1beta and Il-1ra. RESULTS: Neither stress nor experimental gingivitis exerted significant effects on Il-1ra. In controls, we observed significant gender and gender x time effects on Il-1beta; comparing stress groups, gender x time and stress x gender x time interactions became significant. Women show a reduced Il-1beta response to plaque at rest and an increased response under stress. Similar results were found with respect to bleeding on probing. CONCLUSIONS: Gender must be controlled in studies on periodontal responses to pathogens. Stress plays a role in these responses.

Indoor pyrethroid exposure in homes with woollen textile floor coverings.

In order to investigate human's exposure to permethrin from treated woollen textile floor coverings and possible adverse health effects, a study was carried out in 80 private homes in Hannover (Germany) equipped with woollen textile floor coverings (wool wall-to-wall carpets or woven or knotted rugs). For indoor monitoring, permethrin was determined both in house dust and on suspended particles. While permethrin concentrations in house dust (< 2 mm) were high (arithmetic mean: 53.7 mg/kg, 90th percentile 129.1 mg/kg), the permethrin concentrations in the air (suspended particles) were very low (arithmetic mean 2.8 ng/m3, 90th percentile 5.8 ng/m3, first sampling). Additional experiments demonstrate that permethrin on suspended particles result from carpet fiber abrasion (and not from an evaporation/re-condensation process). The internal exposure of the 145 inhabitants participating in the study was determined by biological monitoring (permethrin metabolites in urine). In a first sampling period almost 14% of the samples showed concentrations of the metabolite DCCA and almost 23% of the metabolite 3-PBA above the limit of detection (0.2 microgram/l). A model was developed which allows the calculation of the metabolite concentration in urine due to inhalative uptake of permethrin. Even for the worst case situation the calculated metabolite concentrations were ca. 30 times lower than the experimental results. The observed concentrations of metabolites are comparable to those of the background concentrations of the general population in Germany, suggesting that they must origin from other sources than woollen textile floor coverings. The indoor and biological monitoring data as well as the evaluation of the reported symptoms give no indication of an adverse health effect due to carpet treatment by permethrin.

Prevalence of respiratory symptoms in school children and salivary IgA--an epidemiological study in a rural area of Northrhine-Westphalia, Germany.

An elevated frequency of wheezing was found in school children in a rural area of Northrhine-Westphalia, Germany (Duhme and Keil, Institut für Epidemiologie und Sozialmedizin, Universität Münster, Münster, Germany 1997). In this study the prevalence of wheezing was reinvestigated by including main influencing factors. A cross-sectional survey was performed in all school children visiting school classes 1, 2 and 7, 8 (n = 1161). Two corresponding questionnaires were used: a parental questionnaire and a questionnaire for self-completion by the children aged 12-15. The latter included the ISAAC video questionnaire. The levels of immunoglobulins A, G and M were determined in 995 saliva samples. Testing of lung function (whole body plethysmography before and after physical exercise) was performed in children with and without parent-reported wheezing in the last 12 months (n = 377). Response rate (questionnaire: 93%) and participation rates (saliva samples: 86%, lung function tests: 93%) were high. Our study confirmed higher prevalence of asthmatic symptoms in children aged 6-8 in Ochtrup (13.2%) compared to children of the same age in Muenster (8.5% (Duhme et al., Eur. Respir. J. 11, 840-847, 1998)). However, in the age group 12-15 years the prevalence was significantly lower in Ochtrup (9.8%), when compared to the former investigation and in comparison to Muenster (former survey: 17.9%; Muenster: 13.1%). Prevalence of wheezing was consistently higher in families with atopic disease. Additionally, history of respiratory disease, premature birth and presence of pets during 1st year of life showed a positive association with prevalence of wheezing. Mean salivary IgA levels were 61.4 (SD (standard deviation) 35.1, median: 53.7) mg/l in children aged 6-8 years and 83.4 (SD 39.0, median: 76.3) mg/l in children aged 12-15 years. No significant association between salivary immunoglobulins and wheezing was detected.

Dietary intake of cadmium by children and adults from Germany using duplicate portion sampling.

The dietary intake of cadmium was studied among children and adults from Germany. The study area comprised the highly industrialized Ruhr district as well as the North Sea island Amrum. A total of 229 duplicate samples were collected from 49 individuals between December 1994 and May 1995. The sampling period for each participant was either 3 or 7 days. Cadmium concentrations in duplicate samples were measured by atomic absorption spectrometry. The daily cadmium intakes (geometric mean) for 4 different groups of individuals distributed as follows: for small children (mean age: 1.8 years) from the Ruhr district 0.17 microg/(kg(bw) x day) [range: 0.02-1.62 microg/(kg(bw) x day)], for children (mean age: 3.8 years) from the Ruhr district 0.49 microg/(kg(bw) x day) [range: 0.11-2.06 microg/(kg(bw) x day)], for children (mean age: 3.9 years) living on the North Sea island Amrum 0.35 microg/(kg(bw)-day) [range: 0.09-1.13 microg/ (kg(bw) x day)] and for adults (mean age: 40.9 years) from the Ruhr district 0.37 microg/(kg(bw) x day) [range: 0.05-1.32 microg/(kg(bw) x day)]. Compared to the provisional tolerable weekly intake (PTWI) of 7 microg/(kg(bw) x week) proposed by the WHO the dietary intake of cadmium was rather high. The geometric mean and maximum intake values for the different groups ranged between 24.3-55.7% and 62.7-120.7 respectively of the PTWI. We therefore conclude, that the cadmium exposure of the population needs to be reduced in order to minimize the risk of adverse health effects related to this metal.