The serum capacity to solubilize immune complexes (ICSC) measured by an enzyme-anti-enzyme complex probe.

The capacity to solubilize immune complexes can be readily measured by incubating the test serum with a suspension of an immune precipitate formed by beta-galactosidase and anti-beta-galactosidase antibody, and then reading the enzyme units (EU) liberated in the clear supernatant. Our method is rapid and inexpensive; it can be performed in plates and read in scanning colorimeters. Although on large numbers of observations the ICSC is significantly correlated with the CH50, a few discordant cases suggest that solubilization and haemolysis are functions of the alternative and classical pathways of complement respectively.

A comparison of the ability of beta-galactosidase and horseradish peroxidase enzyme-antibody conjugates to detect specific antibodies.

The ability of two different enzyme-antibody conjugates to detect specific antibodies has been compared. beta-Galactosidase was conjugated to antibodies raised against rabbit Fc fragments using m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS). Horseradish peroxidase (HRP) was conjugated to part of the same batch of antibodies using the periodate method. The beta-galactosidase and HRP labels enabled detection of approximately 8 fmoles and 4 fmoles respectively of human growth hormone (HGH) antibodies, when their enzyme activities were measured spectrophotometrically. The detection limit of the beta-galactosidase label was increased 4-fold when a fluorimetric detection system was employed.

The influence of antigen properties on the conditions required to elute antibodies from immunoadsorbents.

Immunoadsorbents were used to purify a number of antibodies. Using pH 2.0 acid conditions alone it was possible to elute antibodies raised against human growth hormone (HGH) and Fc fragments from such immunoadsorbents with 50% or better recovery of antibody activity. However, to elute antibodies raised against triiodothyronine and cortisol required 6 M guanidine HCl, pH 2.0. The avidities of the purified antibodies were similar to those of the non-purified antibodies. The purified antibodies were stable in solution at 4 degrees C for at least six months.

Ability and fitness to drive of Parkinson's disease patients.

The authors review reports in the literature on the fitness and ability to drive of neurosurgical patients and subjects afflicted by neurological disorders, before focusing on their own series of 204 idiopathic Parkinson's disease (PD) patients. The study sample comprised 173 men and 31 women (average age 70.6 and 74.2 years, respectively) of whom 51, for various reasons, still drove (albeit only short distances). Different variables were examined (Hoehn & Yahr scale values (of the total group and of the subgroup of active drivers), scores for various clinical diseases, and so on) looking for an association between these variables and the number of accidents incurred by PD patients as compared with the healthy population and with a control group of healthy age-matched subjects (ISTAT data). The need for adequate legislation on driving in PD emerges clearly and recommendations are given on which such legislation might be based.

The "soluble sandwich" approach for immunoassays: methodological and instrumental implications.

The simultaneous presence of homogeneous and heterogeneous reactions at different binding sites of a multiepitope antigen makes the description of the kinetic parameters of the so called "one step" solid phase immunometric assays complex. The authors extended the "one step" approach to the concept of the "soluble sandwich" methodology which differs from the former by the delayed solid phase capture of the biotinylated immunocomplex to a streptavidin coated solid support. Using prolactin monoclonal IEMAs as a model, the equilibria involved in the reactions have been studied on a thermodynamic basis through a description of the kinetics of the interactions between biotinylated Mabs and solid phase streptavidin both in presence and/or in absence of the antigen and HRP-conjugated antibody. A comparative evaluation of models in which the biotinylated antibody was previously insolubilized on the streptavidin solid phase has been performed as well. The experimental work was carried out by using 125I labelled McBiot and Prolactin to trace individual interactions and peroxidase/H2O2/TMB systems to develop the enzymatic analytical signals. A new instrument/data reducing system was also optimized to expand the OD reading range provided by conventional, single wavelength colorimeters. The greater flexibility theoretically expected for the "soluble sandwich" approach and the possibility to extend the analyte working range without detrimental effects on the readability of low doses responses have been experimentally confirmed.