Immunotoxicity activity of 1,2,4-trimethoxybenzene from the Paulownia coreana Uyeki. against Aedes aegypti L.

The flower parts of Paulownia coreana were extracted and the major essential oils composition and immunotoxicity effects were studied. The analyses were conducted by gas chromatography-mass spectroscopy (GC-MS) revealed that the essential oils of P. coreana. The P. coreana essential oil (PCEO) yield was 0.175%, and GC/MS analysis revealed that its major constituents were benzyl alcohol (13.72%), phenol, 3,4-dimethoxy-methyl ester (3.64%), phenol, 2-methoxy-3-(2-popenyl)-methyl ester (6.24%), 1,2,4-Trimethoxybenzene (8.32%), tricosane (3.28%), and pentacosane (3.26%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with an LC(50) value of 31.64 ppm and an LC(90) value of 56.43 ppm. 1,2,4-Trimethoxybenzene was the most toxic among the major components with an LC(50) value near 23.1 ppm. The results could be useful in search for newer, safer, and more effective natural immunotoxicity agents against A. aegypti.

Time courses of sensory irritations due to 2-butanone and ethyl benzene exposure: influences of self-reported multiple chemical sensitivity (sMCS).

The individually different effects of exposure to comparable levels of chemicals might be partly explained by dissimilar response sensitivity towards chemicals. Multiple chemical sensitivity (MCS) might be the clinical endpoint of this altered sensitivity. Concerning a subclinical range of chemical sensitivity, 'challenge studies' with people reporting chemical sensitivity are needed to improve the knowledge about such differences. The chemical and general environmental sensitivity questionnaire (CGES) is a standardized screening tool for the selection of this group. In the present study 24 healthy male volunteers, half of them classified as sMCS-subjects, were experimentally exposed to 2-butanone and ethyl benzene at different levels (TLV-level vs. odor threshold). The strength of self-reported sensory irritations (nasal and ocular) and symptoms of bad smell were assessed, prior, during, and after the 4 hours of exposure. The time courses of sensory irritations were affected by sMCS. Across all exposure periods sMCS-subjects showed increasing symptom scores while control-subjects did not. Symptoms of bad smell were affected by three exposure-related factors (substance, level, duration) without any additional influence from the sMCS factor. Starting from these results it could be concluded that the time-depending influence of reported chemical sensitivity is most prominent for subjective data of sensory irritations.

Evaluation of a commercially available ELISA kit as a tool to determine BTEX in groundwater.

The reliability of enzyme-linked immunosorbent assay (ELISA) tests as a screening technique to address groundwater contamination was tested in an area following leakage of gasoline from a petrol station. Immunoassay data of benzene, toluene, ethylbenzene, and o-, m- and p-xylene (BTEX) were compared with results obtained using capillary gas chromatographic analysis. Detection limits were of 20 microg l(-1) for ELISA and 0.3 microg l(-1) for gas chromatography with flame ionization and photoionization detectors (GC-FID/PID) determination. Despite an observed overestimation of BTEX concentrations as given by ELISA, the tests responded reliably to different levels of contamination.

Further investigation of the prohapten concept: reactions to benzene derivatives in man.

p-Phenylenediamine (PPDA) is a strong contact sensitizer which is included in the standard patch test tray and which can also act as an indicator of allergy to related substances by virtue of cross-reactions. In a previous study, the pattern of cross-reactions between PPDA and related substances was investigated in the guinea pig to evaluate the prohapten concept. The results provided some support for this concept, but also indicated that a number of reactive intermediates might be behaving as haptens. This work has now been extended to an examination of the prohapten concept in man in PPDA-allergic subjects. These subjects were tested with 7 substituted benzenes, plus PPDA. Of these, the 1,4-substituted benzenes hydroquinone, Metol, PPDA and p-aminophenol are all capable theoretically of giving rise to benzoquinone by oxidation (after demethylation in the case of Metol). However, as had been the case in the guinea pig, only a limited degree of cross-reaction was observed. Only one of the subjects allergic to PPDA gave a clearly positive allergic reaction to benzoquinone. The data provided only limited support for the prohapten concept in terms of benzoquinone as the ultimate hapten for a range of 1,4-substituted benzenes. As indicated in the guinea pig, a range of reaction intermediates or indeed other oxidation products may be involved. So, for each molecule, the sensitizing activity and potential to give rise to cross-reactions may depend on the balance between routes of skin metabolism.

Anti-phosphorylcholine antibodies with a preferred reactivity for either PC or PC-phenyl represent independent expressions.

Anti-hapten antibodies to phosphorylcholine(PC)-conjugated proteins can be divided into antibodies reacting preferentially with PC (group I) or with PC-phenyl (group II). We have selected two hybridomas producing group II-type anti-PC antibodies of the IgM and IgE classes, respectively. With one exception, NH2-terminal amino acid sequence analyses of the light chains are identical in their first 21 residues and similar to that of M460, but differ from that of group I-type light chains. These results suggest that PC-phenyl-specific group II antibodies are expressed independently of PC-specific group I antibodies.

Investigation of the prohapten concept. Cross reactions between 1,4-substituted benzene derivatives in the guinea pig.

It has been proposed that the cross-reactions seen clinically between hydroquinone and para-phenylenediamine (PPD) arise from the formation of a common hapten, benzoquinone, in vivo, and that these chemicals therefore represent "prohaptens". A series of 1,4-substituted benzene derivatives has been used to examine this prohapten concept in the guinea pig model. Using both topical and intradermal routes of application, it is demonstrated that in the guinea pig 1,4-substituted benzene derivatives capable of oxidation to benzoquinone, including hydroquinone and PPD, show only restricted evidence of cross-reactions. These results support the prohapten concept. However taken in combination with data on cross-reactivity with 1,2- and 1,3-substituted benzenes, rather than giving rise to a single common hapten, they can be more readily interpreted as the formation of a spectrum of antigenic determinants in vivo, some of which are shared in common.

Selective determination of a group of organic compounds in complex sample matrixes by LC/MIMS with on-line immunoaffinity extraction.

An on-line immunoaffinity extraction with liquid chromatography/membrane introduction mass spectrometry (IAE/LC/MIMS) method for the determination of BTEX compounds in complex sample matrixes is described. This method uses an immunoaffinity column (1 mm i.d. x 20 mm) for on-line sample cleanup and enrichment, a 5-micron C18 trapping column (2 mm i.d. x 20 mm) for analyte focusing, a 3-micron C18 analytical column (3.2 mm i.d. x 100 mm) for separation, and a membrane introduction mass spectrometer for quantitation. The immunoaffinity column was evaluated in terms of binding capacity, recovery, and enrichment factor. The method was optimized for the determination of BTEX compounds in a mixture of 30 volatile organic compounds, which showed no matrix interference and a dramatic improvement of the detection limit over that of the LC/MIMS method (up to 474-fold). This method was also used for the determination of BTEX compounds in several gasoline-contaminated water samples, and the results were compared with the EPA reference methods.

Two str1cturally similar haptens each induce a different inherited idiotype.

When mice of the A/J strain were immunized with azobenzenearsonate (ABA) directly coupled to a protein, they produced antibodies that share an inherited cross-reactive idiotype (CRI). In the antigenic determinant that induces CRI, ABA is very probably coupled to tyrosine, and the structure that protrudes from the polypeptide backbone has two benzene rings and a molecular weight of 419. When this same structure is separated from the polypeptide backbone by a spacer of 99 daltons, it induces a different inherited idiotype (ABA-HOP-e) in the same strain of mice. Our data suggest that antibodies with the idiotype CRI recognize the terminal benzene ring and the azo group, but do not fit closely around the second ring structure. Antibodies with the idiotype ABA-HOP-e have fine specificity for both benzene rings. Both idiotypes are inherited and both are linked to genes controlling constant regions of the heavy chains.

Role of the clotting system in cell-mediated hypersensitivity. II. Kinetics of fibrinogen/fibrin accumulation and vascular permeability changes in tuberculin and cutaneous basophil hypersensitivity reactions.

Radioactive tracers and immunofluorescence were employed to detect and quantitate fibrinogen/fibrin deposition in two types of cell-mediated hypersensitivity reactions in the guinea pig. Classic delayed hypersensitivity (DH) reactions to Old Tuberculin and to the azobenzenearsonate hapten were characterized by a progressive increase in the fibrinogen (125-I-HF) content which exceeded that of the albumin tracer (131-I-HSA) and paralleled the development of induration and erythema. Accumulation of 125-I-HF could be related both to increased vascular permeability to 125-I-HF and, more specifically, to retarded efflux of extra vascular 125-I-HF from tuberculin reaction sites. Warfarin inhibited 125-I-HF accumulation and the formation of urea-insoluble 125-I-HF (cross-linked fibrin) as well as induration in tuberculin reactions. Immunofluorescence studies revealed the site of Fib deposition to be extravascular, among the connective tissue fibers of the dermis, similar to that in DH reactions in man. In contrast, little 125-I-HF accumulated in cell-mediated reactions rich in basophils--cutaneous basophil hypersensitivity (CBH) reactions to keyhole limpet hemocyanin, ovalbumin, and dinitrochlorobenzene--due in part to less vascular leakage of macromolecules and to decreased formation of urea-insoluble fibrin. By immunofluorescence Fib deposits were found in CBH reactions in a pattern similar to that in DH reactions, but the intensity of staining was appreciably less. Thus, fibrin accumulation further distinguishes DH from CBH reactions and is very likely responsible for the induration characteristic of DH reactions.

The production and characterisation of an antibody to detect the coccidiostat toltrazuril and its metabolite ponazuril.

The production of an antibody to detect toltrazuril or its metabolite ponazuril is complicated due to structural constraints of conjugating these coccidiostats to a carrier protein. Therefore a search was carried out for a compound that shared a common substructure to use as an antigen mimic. The chosen compound, trifluoraminoether, was conjugated to two carrier proteins (HSA and BTG) and used in the immunisation of six rabbits. Two immunogen doses (1 mg and 0.1 mg) were also used. All six rabbits produced an immunological response to the hapten regardless of the carrier protein or immunogen dose used. The most sensitive polyclonal antibody produced, designated R609, was subsequently characterised. This antiserum exhibited an IC50 of 18 ng ml(-1) using a competitive ELISA format. Cross reactivity studies show that this serum is specific for toltrazuril and its metabolites (toltrazuril sulfoxide and toltrazuril sulfone) but does not cross-react with other coccidiostats such as halofuginone, nitroimidazoles or nicarbazin. This is the first reported production of an antibody capable of specifically binding toltrazuril and ponazuril.