Biomedical subjects

F Gasser

Publications and source records attributed to F Gasser.

113 records · Page 7Linked to original sources

PubMedDate not supplied

[Two-center evaluation of eight kits for antithyroid peroxidase autoantibodies determinations].

We compared eight antithyroid peroxidase antibody assay kits in two centres, by use of panel sera from 269 patients: controls (n = 100), patients with autoimmune thyroid diseases (n = 77 Graves' disease, Hashimoto's thyroiditis), with non autoimmune thyroid diseases (n = 69 nodular goiter, differentiated thyroid carcinoma), and with autoimmune disease without thyroid pathology (n = 23 diabetic subjects, rheumatoid polyarthritis). On the controls sera we observed different distributions of values. The cut-off values of each kit was, in most cases, similar to the value noted in the manufacturer's instructions. In the clinical study, we observed few differences. The majority of assays demonstrated high diagnostic performance. Some false positive results and the non assessment of some sera by competitive immunoassay were observed.

Adolescent↗

PubMedDate not supplied

[Macroprolactin detection: a new approach].

Macroprolactin is a complex of prolactin with immunoglobulins (IgG) that has limited or no biological activity in vivo. Immunoassays for prolactin have variable reactivity with macroprolactin. Therefore the presence of macroprolactin should be considered in the differential diagnosis of hyperprolactinemia. We compared a valid screening test for macroprolactin, polyethyleneglycol (PEG) precipitation, with the determination of the ratio of the results of two prolactin assays: Elecsys with high cross-reactivity with macroprolactin and Centaur with low cross-reactivity. In 59 negative samples subjected to the PEG test (precipitation < 50%), the Elecsys/Centaur ratio ranged between 1.11 and 1.45. Among 35 positive samples (precipitation > 60%), 33 had, as expected, an increased ratio (over 1.45), 1 a normal ratio and 1 a decreased ratio (1.07). This decreased ratio could be due to a particular form of macroprolactin poorly recognised by the Elecsys assay. Among 5 samples in the grey zone (precipitation between 50 and 60%), the ratio was increased in 2, normal in 1 and decreased in 2. Apart from one false negative case (normal ratio with positive PEG test), the results of the Elecsys/Centaur ratio method were in good agreement with those of the PEG test. The ratio method could be helpful for samples with PEG test results in the grey zone, before undertaking a complete analysis of circulating molecular forms by gel filtration chromatography. Out of the 5 five samples in the grey zone, the ratio was 4 times out of the reference range: 2 increased, 2 decreased. Our results also underline the necessity of reevaluating the Centaur prolactin reference range from samples without macroprolactin.

Adolescent↗

PubMedDate not supplied

Changes in serum testosterone levels after myocardial infarction.

To evaluate the effect of a severe non-endocrine disease on testosterone levels we determined the total testosterone (T), free testosterone (fT), myoglobin and myosin plasmatic levels in 18 men at the time of hospitalization for acute myocardial infarction (AMI), and 1, 3, 7 and 21 days later. Five different methods for determining fT were applied and compared; 1) radioimmunoassay after ultrafiltration, 2) direct analogue based radioimmunoassay (RIA), 3) calculation from total T, sex-hormone-binding globulin (SHBG) and albumin concentrations, 4) calculation from total T, SHBG concentrations with albuminemia fixed at 40 g/L, and 5) evaluation by the (total T)/(SHBG) ratio (fT index). After AMI the total T and fT decreased rapidly (minimum at day 1) and then increased until day 21. While a lower sensitivity in detecting small changes was noted for the direct analogue based fT RIA and for the calculation using a fixed albuminemia, the evolving pattern of the 5 different fT determinations was similar despite different absolute values. However, there was a wide scattering in the results from the different methods used to determine fT. Compared to ultrafiltration, the fT values were lower by direct analogue based assay and higher by calculation. There was a trend of correlation between changes in total T and the maximum myosin concentration (r = 0.557, p = 0.02), showing a relationship between the hormonal changes and the severity of the myocardial infarction.

Adult↗

PubMedDate not supplied

[Proposed reference values for nine methods for measurement of free thyroxin].

In connection with a comparative study of nine kits for the measurement of free thyroxin, we determined reference values in a adult control group of 81 women and 73 men. The correlations observed between the kits are associated with very large differences in the results obtained. The reference ranges are more or less broad according to the kits, but narrower than those offered by the manufacturers.

Adolescent↗

PubMedDate not supplied

[Ultrasensitive determination of thyrotropin. Improvement in the performance and reduction of the cost of thyroid function tests].

The characteristics of an ultrasensitive thyrotropin (TSH) assay method using monoclonal antibodies (TSH-U) were determined in euthyroid subjects, either healthy or with extra-thyroid disease, in treated and untreated hyper-and hypothyroid subjects and in subjects under amiodarone. The thyroid function was evaluated by free thyroxine (FT4) and free triiodothyronine (FT3) assays and by TSH tests and TSH response to TRH. With a sensitivity of 1 and a specificity of 0.94, the TSH-U assay proved highly reliable to evaluate the thyroid function. Dysthyroidism can be excluded when TSH-U levels are normal (0.15 to 4.5 microU/ml). In case of low TSH-U level, measurements of FT4 and FT3 and, if required, thyroid gland scintigraphy are necessary to confirm a diagnosis of hyperthyroidism. In contrast, a high TSH-U level is sufficient for affirm diagnosis of hypothyroidism. The TSH-U assay makes the TRH test redundant and can differentiate between hyperthyroxinaemia with euthyroidism and with hyperthyroidism. It is an effective method to detect disorders in thyroid function and it calls for a re-evaluation of thyroid diagnostic strategy.

Adult↗