Bestimmung des Gesamtthyroxins mit dem homogenen Enzymimmunoassay. Vergleich der manuellen und automatisierten enzymimmunologischen Methode mit einem Radioimmunoassay

Ohne Zusammenfassung

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Determination of total thyroxin with the homogeneous enzyme-immunoassay. A comparison of the manual and automated enzyme-immunological determination with the radioimmunoassay

     

Monitoring of serum or saliva theophylline concentrations by a new radioimmunoassay

Conclusions The new radioimmunoassay RIA-mat Theophylline appeared to be highly specific, as none of the drugs structurally related to theophylline or other substances tested showed a noticeable cross reaction. Precision and accuracy are better than comparable assays, the sensitivity of detection is much better than e.g. if using an enzyme immunoassay.Since the required reagents are available as ready-to-use solutions, it is possible to run individual determinations e.g. in emergency cases, as well as large series in a very brief period of time.

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Bestimmung von Theophyllin-Konzentrationen in Serum oder Speichel mit einem neuen Radioimmunoassay

     

Instrument for the mechanization of the capillary radioimmunoassay

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Instrument for the mechanization of the capillary radioimmunoassay

     

Alpha-Fetoprotein: Methodik und klinische Erfahrungen mit einem neuen Radioimmunoassay

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Alpha-Fetoprotein: Methodology and clinical experiences with a new radioimmunoassay

     

Zur Bestimmung des carcinoembryonalen Antigens: Erfahrungen mit einem neuen Radioimmunoassay

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Determination of carcinoembryonic antigen: Experiences with a new radioimmunoassay

     

Separation of bromo- and iodosubstituted thyronines by high-performance liquid chromatography

Summary A reversed-phase high performance liquid chromatographic method on C-18 bonded silica is described for the separation of trisubstituted iodo/bromothyronines, which exert thyroid hormone activity. The composition of the mobile phase has been systematically optimized resulting in a ternary mixture of methanol/acetonitrile/water acidified with trifluoroacetic acid. The applicability of ultraviolet absorption detection, amperometric detection and off-line radioimmunoassay was investigated. The latter method allows detection of the different iodo/bromothyronines down to 40–120 ng/l mobile phase; this sensitivity is high enough for application to thyroid hydrolysates in order to clarify the question as to whether bromine can substitute iodine in the biosynthesis of thyroid hormones.     

Determination of cortisol in guinea pig urine by high performance thin-layer chromatography, high performance liquid chromatography, and thin-layer chromatography/radioimmunoassay

Summary In order to collect urinary samples from unrestrained guinea pigs, animals were kept in their familiar home cages with wood shavings for bedding. Cortisol was removed from shavings by a simple washing step, and an attempt was made to measure its concentrations by high performance thin-layer chromatography (HPTLC), high performance liquid chromatography (HPLC), or thin layer chromatography/radioimmunoassay (TLC-RIA). After intramuscular administration of 25 mg cortisol, cortisol excretion increased from about 20–30 μg/day to 400–500 μg/day (HPTLC: 531 μg/day, HPLC: 493 μg/day; TLC-RIA: 394 μg/day). Similarly, the treatment of the animals with 20 IU ACTH resulted in an augmented cortisol excretion, with mean values of 294 μg/day (HPTLC), 256 μg/day (HPLC) and 143 μg/day (TLC-RIA), respectively. The present study shows, for the first time, that cortisol excretion in unrestrained laboratory animals can be determined. Whilst the cortisol values measured by HPTLC and HPLC agree, the amounts measured by TLC-RIA were significantly lower. These differences are probably due to the presence of substances in urine or shavings which interfere with the radioimmunological determination. Hence, cortisol should be determined either by HPTLC or HPLC. Beside having a desirable specificity, these methods are more suited than TLC/RIA for steroid analysis since they confer the possibility of measuring additional steroids (e.g. precursors and/or metabolites of cortisol) in a single urine extract. This is especially the case for the HPTLC method since substances can be transformed into fluorescent derivatives.     

Separation techniques in radioimmunoassays for digoxin and insulin

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Separation techniques in radioimmunoassays for digoxin and insulin