Search PubMed⌕ Search

Biomedical subjects

R Sapin

Publications and source records attributed to R Sapin.

At least 19 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↗
PubMed1989

[Familial hyperthyroxinemia with dysalbuminemia: screening of 21,000 patients at the occasion of thyroid evaluation].

Serum samples from 21,342 patients undergoing evaluation of thyroid status were screened for familial dysalbuminemic hyperthyroxinemia (FDH) using a specific test based on the measure of charcoal uptake of 125I thyroxine (T4) from serum diluted 1:100 with addition of unlabelled 10(-6) M T4. We found 17 cases of FDH: a higher incidence (8:10,000) than previously reported in the general population (1:10,000). The results of thyroid function tests of patients with FDH are presented: total T4 concentration is increased in only 14 subjects; thyrotropin and free T4 measured by an immunoextraction method are the most useful assays to evaluate the clinical status of these patients.

Humans↗
PubMed1987

TRH-induced TSH and prolactin responses in the elderly.

Since there are divergencies in the thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH) in old age, and since a hypothalamopituitary dysfunction has been suggested in the elderly, we have studied the thyroid function and the TRH responsiveness of TSH and prolactin (PRL) in 56 euthyroid patients over 70 years old, grouped according to age (70-79, 80-89, 90 or more years) and sex. Results were compared to those of 15 postmenopausal women and 11 men. In the elderly patients there was a decrease in plasma tri-iodothyronine (T3) and an increase in reverse T3 (rT3) levels while thyroxine (T4), basal TSH and PRL levels remained normal. The mean TSH and PRL responses to TRH (250 micrograms i.v.) were reduced but there was no age effect within the elderly. Only a sex effect was detected, TSH and PRL responses being appreciably lowered in men. In eight patients without severe disease or malnutrition, the response of TSH was not significant. We conclude that despite an apparent euthyroid status, TSH and PRL responses are blunted in elderly patients, and more in men than in women. These data, consistent with a hypothetical hypothalamopituitary dysfunction, indicate the difficulties of thyroid status assessment in the elderly.

Aged↗
PubMed1987

[Study of salivary cortisol using radioimmunological assay. Diagnostic value].

Salivary cortisol levels reflect the biologically active "free" fraction of blood cortisol. The authors describe the results obtained with the aim of a radio-immunoassay commercial serum cortisol kit, without prealable extraction in different physiological and pathological situations. Salivary cortisol determination appears performant both in nycthemeral studies and in stimulation or freination tests.

Adult↗
PubMed1986

Cephalic phase insulin secretion in relation to food presentation in normal and overweight subjects.

The existence of a preabsorptive insulin reflex is well known in animals but remains controversial in humans. Glycemia and insulin variations following olfactive and visual presentation of a standard meal were studied in 25 subjects, 10 of them (5 men and 5 women) of normal weight and 15 overweight (7 men and 8 women), after a 15 hour fast. Blood samples were collected continuously, every minute for 16 minutes after the meal was presented. The presentation produced an early blood insulin increment, variable in magnitude and time course and occurring between the 3rd and 9th minute, in both normal and overweight subjects. Glycemia variations were not significant. Our study demonstrated a positive correlation between the reflex insulin release, body weight and a conscious effort to maintain current body weight. However, the differences between overweight and normal subjects remained small. The physiological and psychological determinants of the cephalic phase of insulin secretion are discussed.

Adult↗