Chemical Identification and Confirmation of Contact Allergens.

Identification of the etiological chemical agent(s) associated with a case(s) of allergic contact dermatitis (ACD) is important for both patient management and public health surveillance. Traditional patch testing can identify chemical allergens to which the patient is allergic. Confirmation of allergen presence in the causative ACD-associated material is presently dependent on labeling information, which may not list the allergenic chemical on the product label or safety data sheet. Dermatologists have expressed concern over the lack of laboratory support for chemical allergen identification and possibly quantification from patients' ACD-associated products. The aim of this review was to provide the clinician a primer to better understand the analytical chemistry of contact allergen confirmation and unknown identification, including types of analyses, required instrumentation, identification levels of confidence decision tree, limitations, and costs.

From paper electrophoresis to computer-supported interpretation of capillary electrophoresis--clinical plasma protein analysis in Malmö, Sweden.

Protein analyses have been used in Malmö as a routine clinical diagnostic tool since 1953. Most serum samples are submitted for "protein profiles" including capillary zone electrophoresis and rate immune nephelometric quantification of nine proteins (five in urines), although analysis of single proteins may be requested. Standardization between laboratories in our region has been greatly improved by automation, CRM 470 calibration and external quality assurance. We are further extending standardization by developing computer supported interpretations using a program with improved user interface and graphical representation of electrophoretic curves superimposed upon a shaded reference interval. Programming is underway to provide complete automatic interpretation of these curves. Together, capillary electrophoresis (with access to mathematical analysis) and immunochemical quantifications allow a highly automated process accessible to further digital analysis and automated interpretation. Rapid, cost-effective and standardized analysis of serum protein profiles should improve the diagnostic evaluation of many categories of patients.

The structure of sugar chains of Japanese quail ovomucoid. The occurrence of oligosaccharides not expected from the classical biosynthetic pathway for N-glycans; a method for the assessment of the structure of glycans present in picomolar amounts.

While the structure of the major oligosaccharide of Japanese quail ovomucoid was reported earlier (Hase, S. et al. (1982) J. Biochem. 91, 735-737), the structures of the minor oligosaccharide units were investigated for the first time in the present studies. For this purpose, the glycans of the protein were liberated from the polypeptide chain by hydrazinolysis. After N-acetylation, the reducing ends of the oligosaccharides obtained were coupled with 2-aminopyridine, and then the resulting fluorescent derivatives were purified by Bio-Gel P-2 column chromatography and reversed-phase HPLC. The chemical structures of two minor oligosaccharide units were determined with the aid of exoglycosidases, and by methylation analysis and Smith degradation. The results demonstrated that the ovomucoid contains the following two monoantennary glycans: Man alpha 1-6(Gal beta 1-4GlcNAc beta 1-2Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4GlcNAc and Gal beta 1-4GlcNAc beta 1-2Man alpha 1-6(Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4GlcNAc. The latter structure was not predicted by the classical metabolic pathway for the N-glycans to be formed. The structures of three additional minor heterosaccharides were deduced from their elution positions on HPLC together with the results of determination of their molecular sizes and the HPLC elution positions of their enzymatic degradation products. It is noteworthy that for the latter procedure for the estimation of the structures of oligosaccharides only minute quantities of glycans (several hundreds pmol) are required.

A sensitive, rapid, and economic radioimmunoassay of human growth hormone using ethanol-ammonium acetate.

An aqueous solution of 66 per cent ethanol and 6.6 per cent ammonium acetate has been used in the development of a relatively simpler and rapid as well as highly reproducible method of separation of antibody-bound and free hormones in the radioimmunoassay of human growth hormone (HGH). The present assay is sensitive to detect 20 pg. of hormone with a precision of plus or minus 5 per cent, hence, as little as 20 mul of plasma is required to perform the radioimmunoassay. Serum levels of HGH have been found to be approximately 70 per cent of the plasma concentrations in the same subjects.