Comparisons of polybrominated diphenyl ether and hexabromocyclododecane concentrations in dust collected with two sampling methods and matched breast milk samples.

UNLABELLED: Household dust from 19 Swedish homes was collected using two different sampling methods: from the occupant's own home vacuum cleaner after insertion of a new bag and using a researcher-collected method where settled house dust was collected from surfaces above floor level. The samples were analyzed for 16 polybrominated diphenyl ether (PBDE) congeners and total hexabromocyclododecane (HBCD). Significant correlations (r = 0.60-0.65, Spearman r = 0.47-0.54, P < 0.05) were found between matched dust samples collected with the two sampling methods for ∑OctaBDE and ∑DecaBDE but not for ∑PentaBDE or HBCD. Statistically significantly higher concentrations of all PBDE congeners were found in the researcher-collected dust than in the home vacuum cleaner bag dust (VCBD). For HBCD, however, the concentrations were significantly higher in the home VCBD samples. Analysis of the bags themselves indicated no or very low levels of PBDEs and HBCD. This indicates that there may be specific HBCD sources to the floor and/or that it may be present in the vacuum cleaners themselves. The BDE-47 concentrations in matched pairs of VCBD and breast milk samples were significantly correlated (r = 0.514, P = 0.029), indicating that one possible exposure route for this congener may be via dust ingestion. PRACTICAL IMPLICATIONS: The statistically significant correlations found for several individual polybrominated diphenyl ether (PBDE) congeners, ∑OctaBDE and ∑DecaBDE between the two dust sampling methods in this study indicate that the same indoor sources contaminate both types of dust or that common processes govern the distribution of these compounds in the indoor environment. Therefore, either method is adequate for screening ∑OctaBDE and ∑DecaBDE in dust. The high variability seen between dust samples confirms results seen in other studies. For hexabromocyclododecane (HBCD), divergent results in the two dust types indicate differences in contamination sources to the floor than to above-floor surfaces. Thus, it is still unclear which dust sampling method is most relevant for HBCD as well as for ∑PentaBDE in dust and, further, which is most relevant for determining human exposure to PBDEs and HBCD.

Daclizumab phase II trial in relapsing and remitting multiple sclerosis: MRI and clinical results.

OBJECTIVE: Daclizumab is an interleukin 2 receptor alpha chain specific humanized monoclonal antibody that has shown promising therapeutic effects in multiple sclerosis (MS). Daclizumab treatment in patients with relapsing and remitting MS was administered to determine effects on MRI and clinical outcomes. METHODS: Patients with MS on interferon (IFN) therapy but with continuing relapses and contrast enhancing lesions (CEL) were selected. Patients were evaluated with monthly MRI scans and clinical rating scales starting 3 months prior to treatment and then at 0.5 to 27.5 months during treatment. Daclizumab (1 mg/kg IV) was administered twice in the first month (initiated and administered again in 2 weeks), followed by treatments every 4 weeks. IFN was continued until 5.5 months after daclizumab was initiated. Patients were then placed on daclizumab monotherapy. Patients with recurrent CEL were restarted on IFN with daclizumab therapy at (1.5 mg/kg IV) every 28 days. RESULTS: Nine patients qualified for inclusion and completed the trial. Efficacy measured by both total CEL and new CEL (p < 0.001), relapses, timed ambulation, Expanded Disability Status Scale, and Neurologic Rating Scale (p < 0.05 to p < 0.01) was observed. CONCLUSION: Daclizumab was effective in reducing contrast enhancing lesions and improving clinical scores in patients with relapsing and remitting multiple sclerosis with active disease not controlled by interferon therapy. These results provide evidence for long-term efficacy and support further clinical development of daclizumab.

Large-volume programmed-temperature vaporiser injection for fast gas chromatography with electron capture and mass spectrometric detection of polybrominated diphenyl ethers.

A large volume injection fast-GC-MS method has been developed, optimized and evaluated for the determination of polybrominated diphenyl ethers, including the decabrominated diphenyl ether (BDE-209). The programmed-temperature vaporiser injection parameters, temperature programming of the GC oven, and the physical dimensions of the narrow bore GC column were investigated to find the optimal operating conditions for the analysis. Depending on parameter settings the yield of the PBDEs and particularly BDE-209, varies significantly. Volumes up to 125 microl were successfully injected and a fast GC separation was performed, with retention times as short as 6.4 min for the last eluting compound, BDE-209. In a pilot study an air sample, collected at an electronics dismantling facility, was analyzed. Low-resolution mass spectrometry in electron capture negative ion mode was used for detection. Nine BDE congeners, including BDE-209, were identified and quantified.

Mass spectrometric characteristics of decabromodiphenyl ether and the application of isotopic dilution in the electron capture negative ionization mode for the analysis of polybrominated diphenyl ethers.

The mass spectrometric properties of (12)C-and (13)C-labeled decabromodiphenyl ether (BDE-209) in the low-resolution mass spectrometry electron capture negative ionization mode (ECNI-MS) is described in detail and are compared with those of polybrominated diphenyl ethers (PBDEs) with a lower degree of bromination. The mass spectrometric properties of BDE-209 make it possible to apply (13)C-labeled BDE-209 as an internal surrogate standard for the determination of BDE-209 by isotopic dilution. A combination of the [Br](-) and [C(6)Br(5)O](-) fragment ions is proposed for the detection with ECNI-MS in the selected ion monitoring mode to increase selectivity, sensitivity and accuracy in the determination of decabromodiphenyl ether together with other polybrominated diphenyl ethers. The importance of optimizing the instrument parameters to obtain optimal response from the mass spectrometer in the analysis of PBDEs is discussed in detail.

Characterisation of recombinant human IgE-Fc fragments expressed in baculovirus-infected insect cells.

IgE mediates its effector functions through the Fc region and it has been demonstrated that structures in the Cvarepsilon3-domain are crucial for FcvarepsilonR-binding. In order to further study structures of importance for the function of IgE, such as the carbohydrates, fragments with unmodified amino acid sequence were blunt-end cloned and expressed in baculovirus-infected Sf9 cells. Two fragments of human IgE, one encompassing the entire Fc-region (rCvarepsilon2-4) and a smaller one comprising the second and third domain (rCvarepsilon2-3), were produced and characterised with respect to epitope expression, glycosylation and FcvarepsilonR-binding. N-terminal analysis showed the expected VCSRDF-sequence of the Cvarepsilon2-domain, confirming correct cleavage of the secretion signal. Immunoblotting and gel permeation chromatography demonstrated that rCvarepsilon2-4 mainly formed a dimer, whereas rCvarepsilon2-3 also existed as monomers and oligomers. Endoglycosidase-treatment revealed that both fragments were N-glycosylated. In inhibition ELISA, rCvarepsilon2-4 and myeloma protein IgE(DES) reacted in a near equimolar way with monoclonal antibodies against the Cvarepsilon2-, Cvarepsilon3- and Cvarepsilon4-domains, whereas rCvarepsilon2-3 only reacted with anti-Cvarepsilon2 mAbs. Moreover, in FACS analysis rCvarepsilon2-4 interacted with two cell-lines constitutively expressing FcvarepsilonRI or FcvarepsilonRII, whereas rCvarepsilon2-3 lacked reactivity. A substantial reduction in the ability of rCvarepsilon2-4, following endoglycosidase treatment, to react with recombinant alpha-chain of the high affinity receptor for IgE in sandwich ELISA, indicated a role of N-linked oligosaccharides in stabilising receptor binding structures. Taken together, our results show that rCvarepsilon2-4, but not rCvarepsilon2-3, will be useful in studies of structure-function relationships of IgE, including the role of N-glycosylation, since it demonstrated appropriate epitope expression, conformation and ability to bind Fcvarepsilon-receptors.

N-methylputrescine oxidation during cocaine biosynthesis: study of prochiral methylene hydrogen discrimination using the remote isotope method.

[structure: see text] The stereoselectivity of N-methylputrescine (3) oxidation to pyrrolinium ion 4 in Erythroxylum coca during cocaine (1) biosynthesis was studied. The remote isotope method was used to advantage. Each enantiomer of 4-monodeuterated N-methylputrescine served as a precursor for plant feeding. To facilitate mass-spectrometric analysis of products, a 2H3 13C-methyl group was also incorporated into the 4-deuterio-N-methylputrescines. Oxidative deamination of N-methylputrescine was found to be stereoselective; the pro-S hydrogen atom is removed with 6-10:1 selectivity.

Stimulation of feeding behavior and food consumption in the goldfish, Carassius auratus, by orexin-A and orexin-B.

The neuropeptides, orexin-A and orexin-B, have been demonstrated to have a physiological role in the regulation of food intake in mammals. The effects of human orexin-A and orexin-B intracerebroventricular (i.c.v.) injection on the feeding behavior of goldfish (Carassius auratus) were investigated. I.c.v. injection of orexin-A and orexin-B both caused a significant increase in appetite, as indicated by an increased number of feeding acts. Orexin-A and orexin-B both significantly stimulated food consumption, as indicated by increased total food intake during a 60-min observation period; the actions of orexin-A were dose dependent. Orexin-A was more potent than orexin-B in stimulation of both feeding behavior and food intake. These results indicate that orexin peptides are involved in the hypothalamic regulatory pathways of feeding behavior in goldfish.

N-glycosylation influences epitope expression and receptor binding structures in human IgE.

Although human IgE is relatively rich in carbohydrates, there are few studies concerning their structural and functional importance. The low serum concentration of IgE has limited carbohydrate characterisation to a few IgE myeloma proteins. Four to six of the seven potential N-glycosylation sites in the constant region of the epsilon chain seem occupied together with some residual microheterogeneity. We have used a panel of 28 anti-Cepsilon2, 7 anti-Cepsilon3 and 18 anti-Cepsilon4 domain-specific anti-IgE mAbs, and rFcepsilonRIalpha to examine the effect of N-glycosylation on epitope expression of human IgE. Myeloma proteins IgE(DES)-kappa, IgE(ND)-lambda and IgE(UD)-kappa as well as polyclonal IgE were deglycosylated with PNGF and/or sialidase and tested in different ELISA. In all ELISA approaches, the reactivity of most domain-specific anti-IgE mAbs was independent of the glycosylation state of IgE(DES), except for one-third of the anti-Cepsilon2 mAbs. These mAbs reacted better with deglycosylated IgE(DES) in the order of treatment PNGF/sialidase > PNGF > or = sialidase > buffer control. In sharp contrast, the reactivity of IgE(DES) with rFcepsilonRIalpha was not influenced by sialidase but markedly reduced following PNGF or PNGF/sialidase treatment. These findings were neither myeloma restricted nor caused by aggregation, since monomeric IgE demonstrated the same reactivity pattern. Thus. N-glycosylation seems to influence both structure and function of human IgE. The oligosaccharides modulate epitope expression, mainly in the Cepsilon2-domain, as revealed by a subset of mAbs. They also promote subtle changes in the Cepsilon3-domain, leading to a reduced FcepsilonRIalpha binding. These findings suggest physiological implications of carbohydrates in human IgE.

Immunoglobulin levels in patients with carbohydrate-deficient glycoprotein syndrome type I.

BACKGROUND: The characteristic feature of carbohydrate-deficient glycoprotein syndrome (CDGS) type I, a multisystemic disease, is underglycosylation of many serum glycoproteins, such as transferrin. A few cases of severe infections during childhood have been reported and an underlying immunodeficiency has been suggested. Because of this and the fact that all immunoglobulin (Ig) isotypes are glycoproteins we analysed the Ig levels in patients with CDGS I. METHODS: The serum concentrations of IgG1, IgG2, IgG3, IgG4, IgA, IgM, IgD and IgE, and the frequency of the G2m(23) allotype were measured by enzyme immunoassay in 15 patients with CDGS type I. RESULTS: Ten (67%) patients had an elevated level of at least one Ig, when compared to age-related reference ranges. No particular isotype was involved although a tendency towards high IgE levels was registered. The frequency of homozygous G2m(23)-negative CDGS patients (33%) was not different from that of blood donors (34%). CONCLUSION: We conclude that CDGS I patients have no major changes in the serum levels of any specific Ig isotype. The severe infections observed in some CDGS patients are therefore unlikely to involve any Ig deficiency. Our results do not exclude that Ig of patients with CDGS may have altered physiological functions because of abnormal glycosylation.

Modulation of antigen-antibody complexations by immunoglobulins.

In this investigation, the modulating effects of non-immune human IgG and rheumatoid factors (RFs) on antigen-antibody complexations were studied. Non-immune human IgG, as well as RF, were found to inhibit the binding of antigen to specific antibodies of both human and rabbit origin. In addition, human immunoglobulins were also able to modify the composition of preformed antigen-antibody complexes. The effects were detected by immunological methods in two different antigen-antibody systems (human serum albumin-rabbit anti-HSA and tetanus toxoid-human anti-TT). Changes in biological activities could be followed by employing enzymes (glucose-6-phosphate dehydrogenase and human placental alkaline phosphatase) as antigens. The outcome of the effects was found to be dependent on the ratio of antigen to antibody, the antigen-binding properties of the antibody and its origin, and on the properties of the immunoglobulins added. The observed changes could not be explained only by the presence of specific antibodies in the immunoglobulin preparations. The ability of immunoglobulins to modulate antigen-antibody complexations may provide a rationale for the large amounts of non-specific immunoglobulins in the circulation by preventing premature precipitation and promoting the elimination of antigenic molecules.