Radioimmunoassay for TA-0910, a new stable thyrotropin releasing hormone analogue and its metabolite, TA-0910 acid-type, in human plasma and urine

Determination of taltirelin, a new stable thyrotropin-releasing hormone analogue, in human plasma by high-performance liquid chromatography turbo-ionspray ionization tandem mass spectrometry

A rapid, selective and sensitive assay of taltirelin, a novel thyrotropin-releasing hormone analogue, in human plasma has been developed. This method is based on a rapid sample preparation and high-performance liquid chromatography (HPLC) turbo-ionspray ionization tandem mass spectrometry (MS-MS). Analytes were purified from human plasma by SPE cartridge and separated by gradient HPLC. Turbo-ionspray ionization and MS-MS analyses were carried out by PE-Sciex API 3000 tandem mass spectrometer. Taltirelin was separated from its metabolite (acid form) on a semi-micro ODS column in methanol - 0.1% (v/v) formic acid. The selected reaction monitoring by precursor-->product ion combination of m/z 406-->264, was used for determination of taltirelin. The linearity was confirmed in the concentration range of 17-4137 pg/ml in human plasma, and the precision of this assay, expressed as a relative deviation, was less than 9.8% over the entire concentration range with adequate assay accuracy. The results obtained by the HPLC-MS-MS method correlated well with those of the radioimmunoassay method reported previously. Therefore, the HPLC-MS-MS method is useful for the determination of taltirelin with sufficient selectivity and sensitivity on pharmacokinetic studies in human.

Keyhole limpet hemocyanin (KLH): a biomedical review

In this review we present a broad survey of fundamental scientific and medically applied studies on keyhole limpet hemocyanin (KLH). Commencing with the biochemistry of KLH, information on the biosynthesis and biological role of this copper-containing respiratory protein in the marine gastropod Megathura crenulata is provided. The established methods for the purification of the two isoforms of KLH (KLH1 and KLH2) are then covered, followed by detailed accounts of the molecular mass determination, functional unit (FU) structure, carbohydrate content, immunological analysis and recent aspects of the molecular genetics of KLH. The transmission electron microscope (TEM) has contributed significantly to the understanding of KLH structure, primarily from negatively stained images. We give a brief account of TEM studies on the native KLH oligomers, the experimental manipulation of the oligomeric states, together with immunolabelling data and studies on subunit reassociation. The field of cellular immunology has provided much relevant biomedical information on KLH and has led to the expansion of use of KLH in experimental immunology and clinically as an immunotherapeutic agent; this area is presented in some detail. The major clinical use of KLH is specifically for the treatment of bladder carcinoma, with efficacy probably due to a cross-reacting carbohydrate epitope. KLH also has considerable possibilities for the treatment of other carcinomas, in particular the epithelially derived adenocarciomas, when used as a carrier for carcinoma ganglioside and mucin-like epitopes. The widespread use of KLH as a hapten carrier and generalised vaccine component represent other major on-going aspects of KLH research, together with its use for the diagnosis of Schistosomiasis, drug assay and the treatment of drug addiction. Immune competence testing, assessment of stress and the understanding of inflammatory conditions are other areas where KLH is also making a useful contribution to medical research.