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W Frei

Publications and source records attributed to W Frei.

7 recordsLinked to original sources
PubMed1989

Prevention of bridge binding in immunoassays: a general estradiol tracer structure.

Iodinated estradiol tracers were synthesized with three different bridges connecting the radiolabelled moiety to the steroid core: Hemisuccinate, carboxymethyloxime and amide. Taking these iodinated tracers in combination with ten antibodies raised against estradiol-6-CMO-albumin, titers and slopes of calibration curves have been compared to the corresponding data using a 3H tracer. The data indicate that the tracer with the amide bridge is recognized similarly to the tritiated estradiol by all antibodies tested, whereas the two other iodinated tracers exhibit substantial bridge binding. The results suggest that the amide tracer structure can generally be used to improve the quality of estradiol antibodies suffering from bridge binding effects.

Amides↗
PubMed1987

[125I]amatoxin and anti-amatoxin for radioimmunoassay prepared by a novel approach: chemical and structural considerations.

A novel approach for the production of [125I]amatoxin and anti-amanitin is described. The antigen and the starting material for Bolton Hunter iodination is prepared by periodic acid oxidation of the gamma-delta-dihydroxy-isoleucine side chain of alpha-amanitin followed by reductive amination. The antigen seems to be of low apparent toxicity. Chemical, spectroscopic and immunological evidence suggests that the hapten has a secondary structure similar to alpha-amanitin, but a modified tryptophanyl ring system. The establishment of a clinically useful iodinated radioimmunoassay system is possible, because the ring system seems to be of limited immunological importance.

Amanitins↗
PubMed1986

Radioimmunoassay for amatoxins by use of a rapid, 125I-tracer-based system.

In this new radioimmunoassay system for determination of amatoxins in urine and plasma, a novel chemical approach is used for antigen and 125I-tracer production, based on a detoxified alpha-amanitin derivative (aldoamanitin). Total assay time, including data processing, is less than 100 min. The lowest detectable concentration is 1 microgram/L for urine, 0.1 microgram/L for plasma. In the clinically significant range, within-run CVs are less than 8%. This new 125I-based assay is a significant improvement over existing 3H technology in terms of speed, precision, and freedom from interference.

Amanitins↗
PubMedDate not supplied

Simulation by personal workstation for man-machine interface design.

This paper presents a simulation tool which has been developed for Man-Machine interface (MMI) design study, in the context of the European EVA Space Suit System development, under contract of ESA/ESTEC. The main new point is that this simulation is based on a personal workstation, and not on a heavy real-time computer, as in most simulation centres. It will be used in ESTEC to perform low cost simulations of the front part of a manned system, to improve and develop MMI with efficiency.

Computer Simulation↗