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R Bílek

Publications and source records attributed to R Bílek.

25 records · Page 2Linked to original sources
PubMed1994

Synthesis and high-performance liquid chromatographic purification of tritiated thyrotrophin-releasing hormone-like peptides.

A simple method is presented for the synthesis and RP-HPLC purification of tritium-labelled thyrotrophin-releasing hormone (TRH)-like tripeptides. These peptides differ from TRH (pGlu-His-Pro-amide) in that they possess a neutral or acidic residue in place of the histidine of TRH. The method involves the preparation of the appropriate dipeptide by a solid-phase peptide synthesis procedure using 9-fluorenylmethoxycarbonyl (Fmoc) protection. Very small amounts of tritiated glutamine are then converted into tritiated pyroglutamic acid, and coupling to the dipeptide is effected using a mixed anhydride derived from Fmoc-phenylalanine and the tritiated pyroglutamic acid. The required labelled product is then separated from unlabelled material by reversed-phase HPLC, as the hydrophobicity of the phenylalanine-containing product ensures that it is strongly retained. The availability of a series of tritium-labelled markers prepared by this method has permitted the unequivocal identification of certain naturally occurring TRH-like peptides.

Amino Acid Sequence↗
PubMed1994

[Significance of determination of antibodies to TSH receptors (using TRAK) in the diagnosis and monitoring of therapy in endocrine orbital disease].

The elevated antibody level against receptors for TSH assessed by the commercial set TRAK (Henning Berlin) supports the diagnosis of endocrine orbitopathy (EO) which is important in more complicated cases with unilateral EO or EO in euthyroid or hypothyroid patients. During treatment of EO by elimination of the thyroid with radioiodine 131I (with or without previous thyroidectomy) a decline of originally high TRAK values to normal suggests successful elimination. Persistence of high TRAK values is associated with a poorer therapeutic effect of elimination and reasons for this should be sought. In four of 26 such patients the authors found radioiodine accumulation in the residual thyroid tissue, in 8 patients they found a non-accumulating residue by means of sonography. In 14 patients within two years after administration of the radioiodine elimination dose a residue of the thyroid gland was not found by scintigraphy nor by sonography. Improvement of the therapeutic effect occurred in one of these subjects with a drop of the TRAK value after the 30th month following elimination, in another female patient after a high diagnostic radioiodine dose. Improvement of the protrusion after radioiodine treatment with or without previous incomplete thyroidectomy and was recorded in 33 subjects where a drop of the originally high level of TRAK antibodies occurred was significantly greater than in subjects where the TRAK values did not decline.

Autoantibodies↗
PubMed1992

[Determination of serum calcitonin using a non-commercial RIA method].

A radioimmunoanalytical determination of the immunoreactive calcitonine in the humen serum was worked out using the authors' own specific antiserum, the preparation and properties of which are reported in the present paper. The precision and reliability of the analytical procedure is within the usual limits (the intraserial variation coefficient was 8.6%, the calculated sensitivity was 6 pg/ml). The reported procedure was employed to determine calcitonine in a larger number of patients who were examined because of suspected medullar carcinoma of the thyroid gland and in patients suffering from other thyropathies. The results are discussed from the viewpoint of heterogeneity of calcitonine in the circulation.

Calcitonin↗
PubMed1991

Application of non-commercial methods for estimation of immunoreactive serum calcitonin in clinical practice (comparison of two methods).

The authors compared the results of two radioimmunological methods for the estimation of immunoreactive calcitonin in human serum. Parallel with the commercial RIA kit the estimation was made by the authors' own modification of this process with their own specific antiserum and radioligand prepared in the laboratory. The results in a large group of patients with medullary carcinoma of the thyroid gland (MCT) in different stages of the disease revealed that although the values obtained by the two methods differ, there is a statistically significant correlation between the values and the clinical evaluation is also comparable.

Calcitonin↗
PubMed1987

Radioimmunoassay of epitestosterone: methodology, thermodynamic aspects and applications.

A radioimmunoassay system for 17 alpha-hydroxy-4-androstene-3-one (epitestosterone) was developed and evaluated using rabbit antisera against 17 alpha-hydroxy-4-androstene-3-one-3-(O-carboxymethyl)-oxime-bovine serum albumin conjugate, and radioiodinated homologous histaminyl derivative of epitestosterone as a tracer. Two antisera with different specificity were used for radioimmunological determination of epitestosterone in hydrolyzed urine and plasma, respectively. Apparent intrinsic association constants and derived thermodynamic variables for ligand-antibody interaction were measured under various conditions in order to set up an optimal assay protocol. The mean plasma epitestosterone levels for healthy subjects were 0.44 +/- 0.15 nmol.l-1 (means +/- SD) in males and 0.092 +/- 0.056 nmol.l-1 in females. The corresponding concentrations in urine were 320 +/- 70 nmol.l-1 (males) and 273 +/- 100 nmol.l-1 (females).

Body Fluids↗