Pesticides and their behavior in the soil and water

It explains how pesticides can move from the area in which they are applied, and shows how this information can be used, along with otherfactors, to select the proper pesticide.

[Value of the detection of antithyroid antibodies in thyroid pathology]. / Intérêt de la détection des anticorps antithyroïdiens en pathologie thyroïdienne.

Antithyroid microsomal hemagglutination antibody (MCHA) and antithyroglobulin hemagglutination antibody (TGHA) were measured in 629 patients with thyroid disease and 100 controls. Thyroid antibodies were present in 4% of control patients, only in women and at low titer. Thyroid antibodies prevalence was 97% in autoimmune thyroiditis (MCHA: 93%; TGHA: 53%), was 55% in Graves disease before treatment (MCHA: 46%; TGHA: 33%) and 90% in the first year following 131I therapy. Antibodies prevalence was 57% in myxoedema (MCHA: 52%; TGHA: 25%). In patients with iodine overload, antibodies prevalence was 29% in euthyroid patients, 25% in iodine-induced hyperthyroidism and 55% in iodine-induced hypothyroidism. Thyroid antibodies detection should be systematically performed in the routine evaluation of any thyroid disorder. Because of discrepancies between TGHA and MCHA positivity, their simultaneous detection should be performed.

Iodine-induced thyrotoxicosis: analysis of eighty-five consecutive cases.

Iodine-induced thyrotoxicosis was documented in eighty-five cases. Eighty per cent occur in apparently normal thyroid glands; 60% among them occur in males. Amiodarone accounted for 50% of iodine-induced thyrotoxicosis. Mean thyroid hormone levels at diagnosis were: FT1: 21.7 (normal mean: 7.5, arbitrary units); T3: 4.53 nmol 1(-1) (normal: 2.30 nmol 1(-1). Mean 131I- 24-h uptake was 3.5% (normal range in France 25-45%) and was activated by exogenous TSH (mean 27%). The spontaneous cure in nontreated cases was observed within an average 6 months. A phase of biological hypothyroidism (mean FT1: 3.7, T3: 1.23 nmol 1(-1), TSH: 9.6 microU ml-1 (normal TSH range: 1-7 microU ml-1] preceded the return to euthyroidism. Intrathyroid iodine content measured by X-ray fluorescence was high, then fell gradually. Thyroid tissue study showed a large quantity of intrathyroid iodine and the overiodination of thyroglobulin. Histological and electron microscopic studies are reported. Prednisone and in some cases propylthiouracile were found to be effective.

[Congenital hypothyroidism with probable anomaly of thyroid receptiveness to thyrotropin. 2 cases]. / Hypothyroïdie congénitale avec probable anomalie de la réceptivité thyroïdienne à l'hormone thyréotrope. Deux observations.

Congenital hypothyroidism associated with unresponsiveness to thyrotropin (TSH) is a very rare condition. In the two cases reported the thyroid gland was not enlarged and endogenous THS secretion control was normal: the high TSH levels observed during hypothyroidism returned to normal after thyroid hormone replacement therapy and were normally responsive to TRH stimulation. Thyroid iodide clearance was investigated under various conditions of stimulation and inhibition. In hypothyroidism clearance was normal and TSH levels very high. During replacement therapy clearance seemed to be inversely correlated to levels of circulating thyroid hormones; it was almost nil in euthyroidism. Whatever the level of circulating hormones, clearance was not reactivated by exogenous TSH. In one patient in euthyroidism clearance, which was virtually zero, was unmodified after butyric AMPc stimulation, which suggests that the anomaly lies below the AMPc stage.

Thyroid iodine content measured by x-ray fluorescence in amiodarone-induced thyrotoxicosis: concise communication.

Iodine-induced thyrotoxicosis (liT) is characterized by (a) a low radioiodine uptake, increased by exogenous TSH, and (b) a spontaneous evolution towards cure within a few months. An hypothetical pathogenesis of liT is an initial inflation in the stores of thyroid hormones during iodine excess, followed by their sudden discharge into the circulation. Thyroid iodine content was measured by fluorescent scanning in 10 patients with amiodarone-induced thyrotoxicosis and in various control groups. Results were found to be high at the onset of the disease and to decrease during its course. The data agree with the hypothetical pathogenesis. Furthermore they may permit exclusion of a painless subacute thyroiditis, which is the main differential diagnosis of liT.

[Unusual concentrations of triiodothyronine in the serum due to anti-T3 autoantibodies]. / Concentrations insolites de la triiodothyronine du sérum dues à des autoanticorps anti-T3.

Abnormally high T3 serum concentrations incompatible with the patients' clinical thyroid status were observed in a case of Graves' disease and in a euthyroid patient with hyperlipaemia. T3 was in the form of immune complexes precipitable by polyethyleneglycol. Specific anti-T3 autoantibodies were detected in the serum gammaglobulin fraction. The T3 affinity constants of these autoantibodies were found to be as high as 1.10(10) and 7.2.10(10)l/mol respectively. The antibodies interfered with radioimmunological T3 determination, resulting in an apparent increase of T3. However, after extraction, true T3 serum levels remained higher than expected. These findings illustrate the importance of hormone concentrations, affinity constants of binding proteins and equilibrium between free and bound forms in the resulting hormonal effect.

[Iodine excess and iatrogenic thyroid pathology (author's transl)]. / Surcharge iodée et pathologie thyroïdienne iatrogène.

Iodine-induced thyroid disorder is frequent. Amiodarone is responsible for more than half cases of iodine-induced hypothyroidism and hyperthyroidism. Iodine-induced hypothyroidism is detected by the Perchlorate discharge test where its positivity suggests failure of the normal iodine organification. An inhibition of the thyroglobulin proteolysis is probably involved in the pathological process of iodine-induced hypothyroidism. Premature infants are unusually sensitive to iodine excess. Hypothyroidism has been induced in 50% of newborns of 34 weeks or less of gestation after the application, for a few days, of iodized antiseptics. Iodine-induced thyrotoxicosis account for 6% of patients with hyperthyroidism. It occurs most frequently in male with prior normal thyroid gland. The main diagnosis features are the activation of the 131I uptake by exogenous TSH and the spontaneous evolution towards cure. However, in some cases, the severity of the thyrotoxicosis or the slow spontaneous resolution require surgical or medical therapy. From different therapeutic trials it seems that only corticoids and Propylthiouracile are useful. PTU, believed as the drug of choice, has however an incomplete and inconstant effect. The histochemical aspects of the iodine-induced hypo and hyperthyroidism let suppose the possibility of some common mechanism.

[Clinical use of the assay of the thyroxin-binding-globulin (TBG) and of the calculated index: T4/TBG (author's transl)]. / Intérêt clinique du dosage de la "thyroxin-binding-globulin" (TBG) et du calcul de l'index T4-TBG.

The level of TBG in normal adults is 2.21 +/- 0.4 mg/100 ml, without any sex difference. TBG levels are high in the neonatal period (3.26 +/- 0.49 mg/100 ml) and in children under the age of 1 year (2.61 +/- 0.66 mg). Estrogens induce a significant increase (3.96 +/- 1.0 mg) and corticoids a significant decrease of TBG (1.44 +/- 0.32 mg). TBG is also decreased in thyrotoxicosis (1.88 +/- 0.34 mg) but normal in hypothyroidism. There is a strong correlation between T4 and TBG levels, and the T4/TBG ratio appears to be a useful index, which remains constant in normal adults, and under treatment by estrogens and corticoids.

[Study of the hypothalamo-pituitary adrenal function in 16 patients after surgery for pituitary tumor (author's transl)]. / Etude de la fonction corticotrope chez 16 sujets opérés d'une tumeur hypophysaire.

The hypothalamic pituitary adrenocortical function has been studied in 16 patients operated from pituitary tumors (13 adenomas; 3 craniopharyngiomas). Comparisons have been made between corticotropin and cortisol response to lysine vasopressin, insulin induced-hypoglycemia and metyrapone IV and per os. Among these different stimulating tests, insulin induced hypoglycemia and metyrapone per os seem to give the more accurate informations metyrapone per os being more convenient because harmless. Three different groups of patients have been distinguished : one without adrenocortical deficiency; one with a complete deficiency and a third group with a partial deficiency. Correlations have been studied between the degree of the adrenocortical deficiency, the volume of the tumor and the presence of the absence of other anterior pituitary dysfunctions.

[Hyperthyroidism induced by iodine in an apparently normal thyroid gland. A new iatrogenic disease]. / L'hyperthyroïdie induite par l'iode sur une glande thyroïde apparemment normale. Une pathologie iatrogène nouvelle

Iodine-induced thyrotoxicosis was reported to occur in patients with previously altered thyroid gland. Evidence is presented here from 23 cases that iodine-induced thyrotoxicosis may also occur in patients with no prior thyroid desorder and is characterized by: a) an almost undetectable 131I uptake, wich can be activated by TSH; b) a spontaneous improvement within a few weeks or months after withdrawing the high intake of iodine; c) the absence of any detectable thyroid abnormality after recovery.

Synthetic MIF has no effect on beta-MSH and ACTH hypersecretion in Nelson's syndrome.

The effect of synthetic MIF (H-Pro-Leu-Gly-NH2) on beta-MSH secretion was studied in five patients with Nelson's syndrome and in one patient with Addison's disease. Two milligrams of the tripetide were injected intravenously (1 mg in an acute injection, followed by a 30-minute-infusion of 1 mg in 20 ml of saline solution). No consistent effect could be observed during the 90-minute period after the beginning of the infusion. In the same patients, LVP stimulation and dexamethasone suppression tests brought about significant changes in the plasma beta-MSH and ACTH levels.