Authors: R Bílek, T Zelinka, P Vlček...

This work discusses the clinical performance of chromogranin A, free metanephrine and normetanephrine determination in plasma using a radioimmunoanalytical methods for the diagnosis of pheochromocytoma and paraganglioma. Blood samples were collected from 55 patients (46 pheochromocytomas, 9 paragangliomas). A sampling of biological materials was performed preoperatively and about one week, six months and one year after adrenal gland surgery. The comparative group without a diagnosis of pheochromocytoma/paraganglioma consisted of 36 pheochromocytoma/paraganglioma patients more than 4 months after adrenal gland surgery, and of 87 patients, 16 of them with multiple endocrine neoplasia, 9 with medullary and 5 with parafolicullar carcinoma of the thyroid gland. The rest were patients with various adrenal gland disorders. Chromogranin A, metanephrine and normetanephrine were determined in the EDTA-plasma using a radioimmunoassay kits Cisbio Bioassays, France and IBL International GmbH, Germany. Clinical sensitivity was 96 % for the combination of metanephrine and normetanephrine, and 93 % for chromogranin A. Clinical specificity was 100 % for the combination metanephrine and normetanephrine, and 96 % for chromogranin A. Falsely elevated levels of chromogranin A were observed in 1 patient with chronic renal insufficiency and 9 analyses were influenced by the administration of proton pump inhibitors. These results were excluded of CGA specificity. Both the combination of plasma free metanephrine, normetanephrine and chromogranin A as determined by radioimmunoassays, which are simple without the necessity of special laboratory material, are effective markers of pheochromocytoma or paraganglioma. Chromogranin A exerts association to malignity and all markers are associated with tumor mass.

Topics: Adolescent; Adrenal Gland Neoplasms; Adult; Aged; Biomarkers, Tumor; Chromogranin A; Female; Humans; Male; Metanephrine; Middle Aged; Normetanephrine; Pheochromocytoma; Radioimmunoassay; Young Adult

PubMed: 28948824
DOI: 10.33549/physiolres.933719

Review

Authors: R D Grange, J P Thompson, D G Lambert...

Topics: Enzyme-Linked Immunosorbent Assay; Humans; Immunoassay; Immunoenzyme Techniques; Radioimmunoassay

PubMed: 24431350
DOI: 10.1093/bja/aet293

Review

Authors: K Bridget Brosnihan, Mark C Chappell

The renin-angiotensin system (RAS) is a complex circulating and tissue-based system. There are multiple pathways for the formation and degradation of peptides. In order to understand the functions of the system, characterization of angiotensin peptides (products and substrates) is important. Radioimmunoassays with the requisite specificity and sensitivity have been developed to allow for the characterization and quantification of circulating and tissue angiotensins. Here, we describe the appropriate methods for collecting the tissue and blood, the extractions steps required to partially purify and remove larger molecular weight-interfering proteins from tissue and plasma, and the radioimmunoassay of three of the peptides of this system (Ang I, Ang II, and Ang-(1-7)), as well as the verification of immunoreactive identity for Ang II and Ang-(1-7) by combined high-performance liquid chromatography-RIA analysis.

Topics: Angiotensin I; Angiotensin II; Animals; Chromatography, High Pressure Liquid; Humans; Peptide Fragments; Radioimmunoassay; Renin-Angiotensin System

PubMed: 28116709
DOI: 10.1007/978-1-4939-6625-7_7

Review

Authors: Etienne Cavalier

Parathyroid hormone (PTH) determination is of paramount importance for the exploration of diseases related with calcium metabolism and for the follow-up of patients suffering from bone and mineral disorders associated with chronic kidney diseases (CKD-MBD). Unfortunately, the biologically active form of PTH, i.e. 1-84 PTH, circulates in the blood stream with many fragments and post-translationally modified forms, which decreases the specificity of immunoassays. The assays used to measure PTH, either from 2nd or 3rd generation, are not standardised, which may lead to interpretation errors and clinical consequences. Reference ranges for PTH have neither been always correctly established and the stability of the peptide is also a matter of concern. Fortunately, these last years, newer techniques using mass spectrometry (either high resolution or triple quadripole) coupled with liquid chromatography have been developed, which will help to standardise the different assays. Indeed, PTH assays standardisation is one of the task of the IFCC Committee for Bone Metabolism. Such standardisation will allow a better consistency in the interpretation of the results and will promote studies aiming at the establishment of correct reference ranges.

Topics: Humans; Parathyroid Hormone; Radioimmunoassay; Peptides; Chromatography, Liquid; Mass Spectrometry

PubMed: 36640443
DOI: 10.1515/cclm-2022-0942

Authors: Silvia Falso, Sofia Marini, Cinzia Carrozza...

BACKGROUND AND PURPOSE

Acetylcholine receptor antibody (AChR-Ab) detection is crucial in myasthenia gravis (MG) diagnosis and, currently, the radioimmunoassay (RIA) is the gold standard. However, RIA may detect AChR-Ab against nonpathogenic intracellular epitopes. In this study, we performed fixed cell-based assay (F-CBA) in RIA-AChR-Ab positive subjects without MG symptoms, to assess whether F-CBA could show a higher specificity compared to RIA in detecting pathogenic Abs.

METHODS

We reviewed medical records of patients referred to our MG outpatient clinic because of RIA-AChR-Ab detection. MG diagnosis was based on clinical examination, electrophysiology and Ab detection. AChR-Abs were tested by RIA in the whole cohort. Serum samples from RIA-positive asymptomatic subjects were retested by F-CBA.

RESULTS

Of 605 subjects who tested RIA-AChR-Ab positive, MG diagnosis was confirmed in 599. Six subjects were RIA-AChR-Ab positive although they had never had MG symptoms; in four of these subjects AChR-Abs were not detected by F-CBA, whereas the remaining two (both non-MG thymoma cases) were positive also by F-CBA.

CONCLUSIONS

RIA false positivity for AChR-Ab is very rare. Previous literature has demonstrated that F-CBA has higher sensitivity than RIA for MG, especially in ocular cases. Our preliminary results show that, in rare instances, F-CBA may be more specific than RIA for MG diagnosis.

Topics: Humans; Radioimmunoassay; Receptors, Cholinergic; Myasthenia Gravis; Female; Male; Middle Aged; Autoantibodies; Adult; Aged; Sensitivity and Specificity; Retrospective Studies

PubMed: 39118440
DOI: 10.1111/ene.16435

Review

Authors: Kellen DeLaney, Amanda R Buchberger, Louise Atkinson...

Neuropeptides are one of the most diverse classes of signaling molecules and have attracted great interest over the years owing to their roles in regulation of a wide range of physiological processes. However, there are unique challenges associated with neuropeptide studies stemming from the highly variable molecular sizes of the peptides, low concentrations, high degree of structural diversity and large number of isoforms. As a result, much effort has been focused on developing new techniques for studying neuropeptides, as well as novel applications directed towards learning more about these endogenous peptides. The areas of importance for neuropeptide studies include structure, localization within tissues, interaction with their receptors, including ion channels, and physiological function. Here, we discuss these aspects and the associated techniques, focusing on technologies that have demonstrated potential in advancing the field in recent years. Most identification and structural information has been gained by mass spectrometry, either alone or with confirmations from other techniques, such as nuclear magnetic resonance spectroscopy and other spectroscopic tools. While mass spectrometry and bioinformatic tools have proven to be the most powerful for large-scale analyses, they still rely heavily on complementary methods for confirmation. Localization within tissues, for example, can be probed by mass spectrometry imaging, immunohistochemistry and radioimmunoassays. Functional information has been gained primarily from behavioral studies coupled with tissue-specific assays, electrophysiology, mass spectrometry and optogenetic tools. Concerning the receptors for neuropeptides, the discovery of ion channels that are directly gated by neuropeptides opens up the possibility of developing a new generation of tools for neuroscience, which could be used to monitor neuropeptide release or to specifically change the membrane potential of neurons. It is expected that future neuropeptide research will involve the integration of complementary bioanalytical technologies and functional assays.

Topics: Animals; Computational Biology; Immunohistochemistry; Invertebrates; Mass Spectrometry; Neuropeptides; Optogenetics; Radioimmunoassay; Vertebrates

PubMed: 29439063
DOI: 10.1242/jeb.151167

Authors: Jana Uhrová, Hana Benáková, Zdislava Vaníčková...

Determination of renin plasma levels is useful in the diagnosis of hypertension and in the therapeutic follow-up of hypertensive patients. Plasmatic concentration of renin decreases in patients with hypertension due to a primary hyperaldosteronism, contrary to renovascular hypertension where concentrations of renin and aldosterone are both elevated. Blood samples (serum, EDTA plasma) were analysed using two different chemiluminiscent methods CLIA LIAISON® and radioimmunoassay for aldosterone (IMMUNOTECH Beckman Coulter) and renin (Cisbio Bioassay) measurements were compared. We used both methods to ascertain the correlation between serum vs. EDTA plasma levels of aldosterone (RIA, CLIA) and renin (IRMA, CLIA) and to compare aldosterone to renin ratios for CLIA and for radioimmunoassay: serum aldosterone to plasma renin and plasma aldosterone to plasma renin. We compared serum aldosterone CLIA vs. RIA (rP=0.933, P<0.001) and plasma renin determined using CLIA vs. IRMA (rP=0.965, P=0.062). Furthermore, we used both methods to establish the correlation between the serum vs. plasma levels of aldosterone: RIA (rP=0.980, P<0.001); CLIA (rP=0.994, P=0.353) and serum vs. plasma levels of renin: IRMA (rP=0.948, P<0.001); CLIA (rP=0.921, P=0.011). Aldosterone (serum, plasma) to plasmatic renin ratios for CLIA (rP=0.999, P=0.286) and for radioimmunoassay (rP=0.992, P=0.025). Our data demonstrate that renin and aldosterone concentrations obtained using CLIA correlate with renin and aldosterone concentrations using radioimmunoassay methods. Correlation coefficients of pair results ranged from 0.921 to 0.994. Aldosterone (serum, EDTA plasma) to plasmatic renin ratios are comparable and any of them can be used with no significant differences found.

Topics: Aldosterone; Humans; Hyperaldosteronism; Luminescence; Radioimmunoassay; Renin

PubMed: 34137684
DOI: 10.14712/23362936.2021.9

Review

Authors: Nicolai J Wewer Albrechtsen, Jens F Rehfeld

Gastrointestinal hormones are peptides, and the gastrointestinal tract is the largest endocrine organ in the body for production of peptide hormones. As a premise for accurate measurement of gastrointestinal hormones, the present review provides first an overview over the complex biology of the hormones: The structures and structural homologies; biogenetic aspects; phenotype variabilities; and cellular expression in- and outside the digestive tract. Second, the different methodological principles for measurement are discussed: Bioassay, radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), mass-spectrometry (LC-MS/MS) and processing-independent analysis (PIA). Third, the variability of secretion patterns for some of the gut hormones is illustrated. Finally, the diagnostic value of gut hormone measurement is discussed. The review concludes that measurement of gastrointestinal peptide hormones is relevant not only for examination of digestive functions and diseases, but also for extra-intestinal functions. Moreover, it concludes that, so far, immunoassay technologies (RIA and ELISA) in modernized forms are still the most feasible for accurate measurements of gastrointestinal hormones in biological fluids. Mass-spectrometry technologies are promising, but still too insensitive and expensive.

Topics: Alternative Splicing; Animals; Biological Assay; Blood Chemical Analysis; Enzyme-Linked Immunosorbent Assay; Gastrointestinal Hormones; Gene Expression; Humans; Mass Spectrometry; Peptide Hormones; Radioimmunoassay

PubMed: 33811948
DOI: 10.1016/j.peptides.2021.170545

Authors: K W Simpson

Topics: Animals; Biomarkers; Cat Diseases; Cats; Pancreatitis; Radioimmunoassay; Sensitivity and Specificity; Tomography, X-Ray Computed; Ultrasonography

PubMed: 11467588
DOI: No ID Found

Review

Authors: N A Lisitsyn, A A Chernyĭ, I G Nikitina...

This review describes current methods of protein immunoanalysis: radioimmunoanalysis, ELISA, immuno-PCR, electrochemical analysis and chromatin immunoprecipitation, as well as main areas of their application.

Topics: Chromatin Immunoprecipitation; Electrochemical Techniques; Enzyme-Linked Immunosorbent Assay; Immunoassay; Polymerase Chain Reaction; Proteins; Radioimmunoassay

PubMed: 25842856
DOI: No ID Found