Structural biology, homology modelling and rational drug design require accurate three-dimensional macromolecular coordinates. However, the coordinates in the Protein Data Bank (PDB) have not all been obtained using the latest experimental and computational methods. In this study a method is presented for automated re-refinement of existing structure models in the PDB. A large-scale benchmark with 16 807 PDB entries showed that they can be improved in terms of fit to the deposited experimental X-ray data as well as in terms of geometric quality. The re-refinement protocol uses TLS models to describe concerted atom movement. The resulting structure models are made available through the PDB_REDO databank (http://www.cmbi.ru.nl/pdb_redo/). Grid computing techniques were used to overcome the computational requirements of this endeavour.

Summary Accurate measurement of low IgE concentrations is technically difficult. In this paper results obtained by a direct sandwich and three inhibition methods of radioimmunoassays are compared. For values above 50 U/ml good correlation was obtained with all methods. Below 50 U/ml, however, the inhibition methods tended to yield falsely high values. For very low concentrations, 1–10 U/ml the best correlation was obtained between the direct sandwich test (PRIST*) and the inhibition test using a correction factor to allow for the non‐specific effect of serum. The four methods were used to quantify IgE in cord serum samples from healthy individuals. The mean value obtained by PRIST was 0.4 U/ml and by the inhibition test, using a correction factor, 0.6 U/ml respectively. Because of its greater simplicity the direct sandwich test is recommended.

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A two-site monoclonal antibody-enzyme immunoassay (MEIA) for carcinoembryonic antigen (CEA) was developed that uses two monoclonal anti-CEA antibodies, which recognize two different epitopes in the peptide moiety of CEA. The assay was sensitive to 0.5 pug/liter and had a measuring range of 0.5-200 pig of CEA per liter. It was highly specific inasmuch as none of three known CEA-related substances, "nonspecific crossreacting antigens 1 and 2" (NCA-1 and NCA-2) and biliary glycoprotein I (BGP I), reacted in the assay. NCA

Summary Serum samples from eighty‐one patients with suspected penicillin allergy were investigated with Phadebas RAST using the penicillin derivatives Benzylpenicilloyl‐human serum albumin (PBO‐HSA) and Phenoxymethylpenicilloyl‐human serum albumin (PMPO‐HSA) and the results were compared with skin test results and clinical data. Of the sixty‐one patients who had anaphylactic shock and/or urticaria as a possible consequence of penicillin administration, reagins against PBO‐HSA and PMPO‐HSA could be detected in thirty‐four cases (56%). Five per cent of these patients, with positive RAST results, showed negative skin tests; in the other 95% both RAST and skin tests were positive. All, except eight, of the RAST‐negative patients had had their adverse reactions at least 2 years prior to the blood sampling and in some of these cases skin tests were also negative. RAST and provocation test results agreed in 80% of the cases where exposition was performed. It is concluded that the RAST technique is a valuable diagnostic tool for the detection of immediate type hypersensitivity to penicillin.