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R Sapin

Publications and source records attributed to R Sapin.

15 recordsLinked to original sources
PubMed1991

[Evaluation of thyroid function after myocardial infarction].

The myocardial infarction (M.I.) constitutes an exemplary acute severe affection able to modifie hormonal concentrations. The total and unbound thyroid hormones, reverse T3 (rt3), TSH, and cortisolemia were determined in 24 patients during a period of 21 days in order to compare them to different markers of severity of MI. The initial phase of the disease is characterized by low concentrations of total and free T3 and high concentrations of rT3 combined with more often than not normal total and free T4 and TSH values contrasting with an increase in cortisol levels. The abnormalities were more pronounced the day after admission and then progressively amend. There are several statistic relationship between the marker of severity of MI and thyroid hormones. In the same way total T3 is all the more decreased especially since myoglobin, CPK-MB, ST amplitude and ventricle ejection fraction are more disturbed. Severe forms of MI induces a pseudo central thyroid insufficiency with low T3, low T4 and a tendency to TSH decrease. Total T3 blood levels may usefully contribute to the elaboration of an MI severity index.

Adult↗
PubMed1990

Analytical and clinical evaluation of a new one-step non-analogue radioimmunoassay for serum-free thyroxine.

We evaluated analytically and clinically the new one-step non-analogue free thyroxine (FT4) assay (Amerlex-MAB from Amersham), using a labelled monoclonal thyroxine-specific antibody as tracer, in comparison with the Gammacoat two-step FT4 kit (Baxter). Analytical performances of the new kit were excellent: within and between run coefficients of variation were less than 5% in the working range. Clinical sensitivities for hypo- and hyperthyroidism were comparable for both kits (FT4 Amerlex-MAB 95% confidence interval: 12-25 pM). When serum was supplemented with albumin we observed a slight decrease in FT4 values measured by both kits. When oleate was added to serum we noted a moderate increase with the Amerlex-MAB kit up to 10 mM oleate added and a much more marked increase with the two-step kit. Results obtained with patients from particular euthyroid populations, known to have low albumin or high free fatty acids concentrations or to have perturbed FT4 results when measured by an analogue-based method, agreed with those of the in vitro studies. With these patients the specificity of the Amerlex-MAB FT4 results was good but slightly decreased compared with the two-step FT4 method, except for heparin-treated patients who were all classified according to their euthyroidal status (17/17 instead of 13/17 with the two-step kit).

Antibodies, Monoclonal↗
PubMed1990

[Antibody interference in immunoassays with markers].

Antibody interferences in competitive and non-competitive immunoassays are discussed for analyte specific and reagent specific (anti-antibodies) antibodies. The effect on apparent measured concentrations is described and the methods to detect and, when possible, to eliminate these interferences are reported.

Antibodies↗
PubMed1990

In vitro and in vivo effects of increased concentrations of free fatty acids on free thyroxin measurements as determined by five assays.

To compare in vitro and in vivo effects of increased concentrations of free fatty acids (FFA) on free thyroxin (FT4) values, we measured FT4 in three pooled sera supplemented with oleate and in serum from 18 euthyroid patients before and after an infusion of fat emulsion (Intralipid). We used five FT4 RIA kits: two two-step methods [Gammacoat, Baxter (GC); Ria-gnost, Behring (RG)], two analog RIAs [Amerlex-M, Amersham (AM); Coat-Ria, BioMérieux (CR)], and one kit with labeled antibodies [Amerlex-MAB*, Amersham (AA)]. In vitro, at the maximum oleate addition of 5 mmol/L, FT4 increased when measured by the GC and RG kits, decreased by the AM kit, and showed no significant change by the CR and AA kits. In vivo, post-Intralipid, FFA concentrations rose significantly and the FT4 changes agreed with the results of the in vitro experiments, except for the RG kit, for which FT4 increased in only nine patients. We conclude that in vitro oleate addition is useful to predict the in vivo effect of increased FFA on FT4 values; moreover, in serum from euthyroid subjects with high concentrations of FFA, FT4 analyzed with the CR or AA kits should better agree with normal results for thyrotropin than FT4 values measured with the other kits.

Chromatography, Gas↗
PubMed1989

[Diminution of thyroid stimulating hormone level but normal levels of thyroid hormones. Demonstration of occult hyperthyroidism].

The finding of a low basal concentration of thyroid-stimulating hormone (TSH) in the absence of high thyroid hormone levels is difficult to understand. In order to elucidate the meaning of such a dissociation, 22 patients without history of thyroid disease and showing clinical signs compatible with thyrotoxicosis were explored by the thyrotrophin-releasing hormone (TRH) test, by thyroid radioisotope scanning and, in case of high nodular uptake, by the triiodothyronine suppression test. A specific surgical, isotopic or medical treatment was instituted in the 17 patients who had a high nodular uptake unsupressible by triiodothyronine. During a clinicobiological re-evaluation carried out 6 months later, a significant clinical improvement was observed in 8 patients, and 12 patients whose free thyroxine level had decreased showed normal TSH levels. These results underline the value of thyroid radioisotope scanning in patients with isolated diminution of TSH. They confirm the reality of occult hyperthyroidism with normal thyroid hormone levels by the benefits observed after specific treatment.

Aged↗
PubMedDate not supplied

[Treatment and monitoring of primary hypothyroidism].

Treatment of primary hypothyroidism requires a long-term hormonal therapy with levothyroxine which restores a normal TSH value. In a series of 192 patients followed up for at least 3 years we tried to evaluate the variability of maintenance dosage and to analyse the factors predictive of replacement dosage. The L-T4 dosage varied from one individual to the other, from 0.6 to 3.2 micrograms/kg. The mean maintenance dosage (118 +/- 38 micrograms/day) was similar in men and women weight for weight, but it was higher in subjects aged under 60 and in those with Hashimoto's or congenital hypothyroidism. There is a positive linear relation between the equilibrium dose and the TSH value (n = 0.84; p < 0.001) and a negative relation with the L-T4 concentration (n = 0.71; p < 0.001). The yearly variation of dosage in each individual was small (about 3.5%) and of the same order as the variation of weight. We conclude that the L-T4 maintenance dosage depends on the cause of hypothyroidism, on the importance of biochemical abnormalities and on the patient's age, sex and weight. In practice, however, the necessary dosage is difficult to predict. In the equilibrium phase the need for replacements is remarkably stable. A yearly assay of baseline TSH seems to be sufficient to evaluate the quality of hormonal compensation in the absence of intercurrent events.

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↗