Sensitization cross reactions

This natural resin is used in adhesives, e.g., adhesive tape, epilating wax, and as a tacky wax to prevent slipping (violinists, gymnasts). It is a residue after distilling oils from certain pine trees. Gum rosin and wood rosin are the two main types. They contain abietic acid which may be the sensitizer. Cross-reactions between rosin and balsam of Peru occur (Fisher 1973, p. 173 Hjorth 1961). 

Cross-reactions with aspirin and NSAIDs are of practical importance. Typically, AIA patients are sensitive to all NSAIDs that preferentially inhibit COX-1 (table 2). Acetaminophen (paracetamol), a weak inhibitor of COX-1, is regarded as a relatively safe therapeutic alternative for almost all patients with AIA. High doses of the drug (>1,000 mg) have been reported to provoke mild, easily reversed bronchos-pasm in some AIA patients [13]. Some rare, well-documented cases of coexistence of aspirin and paracetamol sensitivity have been described. However, according to a recent meta-analysis, less that 2% of asthmatics are sensitive to both aspirin and paracetamol [14]. 

Sensitized cross-dimerizations form a second group with a few examples shown in Eqs. 24—27. Most examples involve electron-deficient olefins as one addend. The reactions are again highly regioselective... 

The principal advantages of RIA are its sensitivity, specificity and simplicity of operation. There are three main disadvantages. Firstly, the lengthy development periods for new methods often result from the difficulties of producing the specific binding agent. Secondly, cross-reactions with other molecules similar to the analyte can sometimes interfere. Thirdly, poor precision can result unless careful control of experimental conditions is employed to ensure reproducible binding reactions. Relative precisions of 1-3% are typical. 

Snitkoff et al. [75] reported the development of an EIA for the detection of ciprofloxacin in serum, which was sensitive at picogram per milliliter levels of the antibiotic and no cross-reaction with its metabolites was observed. Gobbo et al. [118] recently described the production of PAb for ciprofloxacin with the aim of detecting fluoroquinolones in Brazilian livestock. On the other hand, Bucknall et al. [77] produced antibodies for quinolones and fluoroquinolones with the aim of developing both generic and specific immunoassays. ELISAs for ciprofloxacin, enrofloxacin, flumequine, and nalidixic acid were developed with sensitivity values around 4 pg kg 1 (on both the generic and specific assays) in bovine milk and ovine kidney. 

From table 32.2 it is evident that the highest cross-reaction is 5% with N-desmethylchlordiazepoxide while demoxepam, N-desmethyldiazepam, diazepam and clonazepam displayed less than 1% inhibition. However, the RIA method appears to be reliable over a range of 2-100 ng per tube of chlordiazepoxide and, therefore, the sensitivity limit stands at 20 ng ml 1 using a 1.0 ml sample of plasma. 

Indeed, the oxidation of Fe(CN)g by O2 (as well as by H2O2 and BrOj) proceeds via the rds of dissociation of the hexa- to the penta-cyano complex. The value of k in (8.90) is 5.6 X lO M s at pH > 3.8. Traces of Fe from decomposition of the cyano complex promote catalytic oxidation (Prob. 19). A large number of complexes of the type Fe(CN)5X" for both Fe(II) and Fe(III) have been studied and cross-reaction redox kinetics abound. Care has to be exercised in the use of FeiCN) . Daylight can induce changes in the complex even within an hour and catalytic effects (traces of Cu Sec. 3.1.4) have to be considered. In addition, the sensitivity of the values of and rate constants to medium effects lessen the value of the iron-cyano complexes as reactant partners for the demonstration of Marcus relationships. Nevertheless, they, with other inorganic complexes, have been extensively employed to probe the peripheral characteristics of metallopro-teins. 

Application of the RIA. The RIA was initially used to evaluate the cross-reaction of the STXOL antisera to STX. The antibody was found to have excellent STX cross-reactivity (93%). Subsequent preparation of a logit/log (37) standard curve for STX (Figure 4) demonstrated that the chosen assay format would give good reproducibility and a desirable order of magnitude linear sensitivity range. 

Bisphenol A causes slight skin and eye irritation. It did not cause contact allergy in a guinea pig maximization test. Furthermore, no cross-reactions were detected when animals sensitized to the diglycidyl ether of bisphenol A were tested with bisphenol A. 

Cross-sensitivity Allergic cross-reactions may occur that could prevent future use of any or all of these antibiotics - Kanamycin, neomycin, paromomycin, streptomycin, and possibly, gentamicin. 

The tropomyosins of mite and insect species show some sequence identity (63-65%) with snail tropomyosin and share similar epitopes (EFSA, 2006 Fig. 4.1). Still, tropomyosin appears to play a minor role in the crossreactivity of dust mites and snails (Asturias et ah, 2002 Guilloux et ah, 1998 Van Ree et ah, 1996a). Other non-tropomyosin allergens are likely to be involved including Der p 4 (amylase), Der p 5, Der p 7, and hemocyanin (Martins et ah, 2005 Mistrello et ah, 1992 Van Ree et ah, 1996). While snail is the main molluscan shellfish species involved in cross-reactions with dust mites, some patients allergic to dust mites and snails are also sensitized to mussels (DeMaat-Bleeker et ah, 1995 Van Ree et ah, 1996b). In their study of 70 patients sensitized to molluscan shellfish, Wu and Williams (2004) noted that 90% were also sensitized to dust mites. However, the clinical significance of this sensitization was not documented. 

Immunochemical approaches are cheaper, readily adaptable, rapid, portable, and reduce the need for expensive analytical equipment. They can also be used to simultaneously assay a large number of samples over a short period of time. One of the major factors that still hmits the use of this technique in the detection of a wider range of PPCPs in the environment is the lack of suitable antibodies sensitive to most PPCPs that occur in the environment. Furthermore, immunoassay accuracy can be susceptible to cross reactions and other effects from the matrix, giving false positives in some instances (Huang and Sedlak, 2001). Thus, it is recommended that immunoassay analytical results be validated with GC- or LC-based methods. 

The possibility of recognising several molecules with different sensitivities causes dispersion in the results. How does one know if a cross-reaction (a false positive)... 

While ionic strengths as low as 1 mM have been used with the cell illustrated in Figure 1, most LCEC experiments are carried out with a minimum of 0.05 M buffer salts in the mobile phase. Postcolumn mobile phase changes (pH, ionic strength, solvent content) and post-column reactions (redox cross reactions, derivatiza-tions, enzyme catalyzed reactions) can expand the utility of electrochemical as well as other detectors. These subjects have recently been treated in some detail (9). Suffice it to say that direct detection, without post-column chemistry, is always preferable (more reliable, more sensitive, less expensive). 

Widespread occurrence of the mentioned proteins may, according to some authors, be the cause of polysensitization, i.e., sensitivity to many different products and it may account for some cross-reactions, for instance between latex and celery and bananas (Jgdrychowski 2001), which have been observed in peaches, apricots, plums, and apples a high structural affinity between the proteins of the fruits mentioned and respective sweet com proteins has been documented (Pastorello et al. 2001). 

Several authors report coexisting clinical soy allergies in 5%-50% of patients with cows milk allergies (NDA Opinion 2004). It is unclear whether soy allergy represents a de novo sensitization or a cross-reaction of a soy protein component with caseins from milk (Rozenfeld et al. 2002). However, due to homology in the amino acid sequences of soybean and cow s milk allergens of 50%-70%, cross-reactivity is likely (Wilson et al. 2005). 

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