Browsing by Author "MICHAUD, P"

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    A PREPUBERTAL SURGE OF THYROTROPIN PRECEDES AN INCREASE IN THYROXINE AND 3,5,3'-TRIIODOTHYRONINE IN NORMAL-CHILDREN
    (ENDOCRINE SOC, 1991) MICHAUD, P; FORADORI, A; RODRIGUEZPORTALES, JA; ARTEAGA, E; LOPEZ, JM; TELLEZ, R
    The variations in plasma levels of TSH, T4, T3, and rT3, during the pubertal period, were studied in 647 school students from the urban area of Santiago in Chile (47% males and 53% females) with ages ranging between 7.5 and 15 yr. The subjects were grouped by age in consecutive intervals of 6 months each, and pubertal development was determined in every subject. TSH showed a significant increase, reaching a peak in the 9- to 9.5-yr interval. The same was found for T3 and T4, which reached a peak by 10 and 11 yr. The T4/T3 ratio did not show any significant variation with age. After 9.5 yr, a decrease in rT3 and increase in the T4/rT3 ratio was found. The TSH peak preceded the onset of clinical pubertal development, while the T3 and T4 peaks coincided with this onset. The variations in rT3 suggest an increase of peripheral conversion of T4 to T3. These transient events, not described until now, could be termed thyroidarche and could have a significant effect on pubertal growth and development.
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    ADRENAL MACROTUMORS DIAGNOSED BY COMPUTED-TOMOGRAPHY
    (1990) LOPEZ, JM; FARDELLA, C; ARTEAGA, E; MICHAUD, P; RODRIGUEZ, JA; CRUZ, F
    Adrenal tumors larger than 6 cm are unusual but show a greater incidence of malignant etiologies than smaller adrenal tumors. The scarce information about adrenal macrotumors (AMT) induced us to study prospectively all patients who were seen in our clinic during the period 1984-1988 and were diagnosed by computed tomography (CT) to have an adrenal mass .gtoreq.6 cm. The clinical characteristics, including the main complaint, tumoral secretory activity, CT findings and histologic diagnosis from 18 patients are described; they represented a 0.3% of the total amount of abdominal CT studies performed. Seventy-two % of AMT resulted to be non cortisol or catecholamines secreting masses, and from them, a 38% corresponded to malignant etiologies characterized by marked and rapid weight loss. Four out of five hormone secreting AMT corresponded to pheochromocytomas, while the fifth one resulted to be a bilateral macronodular hyperplasia secreting cortisol. In two cases AMT did not correspond to a genuine adrenal mass, resulting to be a malignant histocytoma in one case and a hydatidic cyst in other one. When performed in two occasions, a percutaneous needle biopsy was a valuable diagnostic tool, permitting to diagnose a lymphoma and a tuberculoma. In conclusion: 1) AMT correspond mainly to non cortisol or catecholamines secreting tumors, often malignant; 2) not all AMT diagnosed by CT correspond to true adrenal masses; 3) percutaneous needle biopsy can be a helpful procedure for diagnosing nonfunctioning solid AMT.
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    EFFECT OF ORAL POTASSIUM SUPPLEMENTS ON URINARY KALLIKREIN EXCRETION IN SHEEHANS SYNDROME
    (1988) LOPEZ, JM; MAHANA, D; RODRIGUEZ, JA; MICHAUD, P; ARTEAGA, E; FARDELLA, C
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    EFFECT OF THE COMBINATION OF DEXAMETHASONE AND SODIUM IPODATE ON SERUM THYROID-HORMONES IN GRAVES-DISEASE
    (1983) ARTEAGA, E; LOPEZ, JM; RODRIGUEZ, JA; MICHAUD, P; LOPEZ, G
    To investigate the effect of the combination of dexamethasone (Dex) and sodium ipodate (SI) on hyperthyroidism, 24 patients with typical Graves'' disease, divided into 4 groups of 6 persons each were studied. Three groups (Study I) were studied acutely (24 h) to determine the effects of Dex (5 mg every 12 h i.m.), SI (1 oral dose of 3 g) and both drugs at the same doses, upon T4, T3 and rT3 [thyroxine, triidothyronine and reverse triiodothyronine] at 0900 h before therapy was started and 24 h later. The group on Dex and that on SI had a similar T3 decrement of 25.9 .+-. 4.0% and 35.8 .+-. 5.0%, respectively, (P < 0.05), whereas the effect of both drugs combined was greater (64.2 .+-. 3.6%; P < 0.01, Dex, and P < 0.01, SI, respectively). The increment of rT3 was markedly greater in those patients on SI than in those on Dex (561 .+-. 149.2% and 58.9 .+-. 11%, respectively, P < 0.025). A 4th group (Study II) was studied for 7 days while receiving both Dex (1 mg orally 3 times per day) and SI (500 mg orally 3 times per day). Both T4 (from 18.8 .+-. 1.1 to 13.1 .+-. 1.1 .mu.g/dl, P < 0.02) and T3 (from 593 .+-. 41 to 136.3 .+-. 12.7 ng/dl, P < 0.001) decreased at day 8. The initial brisk increment of rT3 at 24 h (808 .+-. 149%, P < 0.005) then diminished concomitantly with the fall of its precursor, T4. The pulse rate correlated with plasma T3 concentration (r = 0.67, P < 0.001) and varied from 104.7 .+-. 3.9 on day 1 to 77.3 .+-. 3.0 beats/min (P < 0.001) on day 4 and then remained stable. Dex and SI have potent inhibitory effects at the level of peripheral conversion of T4 and on the thyroid gland itself and the combined use of these drugs significantly increases these effects. Considering the rapid clinical improvement of thyrotoxicosis achieved with both drugs, this regimen may be valuable in the initial treatment of some patients.
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    RESPONSE OF THE MATERNAL, FETAL, AND NEONATAL PITUITARY-THYROID AXIS TO THYROTROPIN-RELEASING-HORMONE
    (1986) MOYA, F; MENA, P; HEUSSER, F; FORADORI, A; PAIVA, E; YAZIGI, R; MICHAUD, P; GROSS, I
    Thyrotropin releasing hormone (TRH) readily crosses the placenta and stimulates the fetal pituitary. We studied the response of the maternal and fetal pituitary-thyroid axes to TRH and the influence of prenatal exposure to TRH on the physiological postnatal increase in thyrotropin (TSH) and triiodothyronine (T3) in the neonate. Twenty-six pregnant women received TRH (400 or 600 .mu.g) intravenous or saline (controls) either 2 or 12 h before elective cesarean section at term. Administration of 400 .mu.g of TRH resulted in significant elevations of maternal TSH (15.7 .+-. 2.9 versus 3.2 .+-. 0.4 .mu.U/ml, p < 0.01) and prolactin (416 .+-. 94 versus 223 .+-. 41 ng/ml, p < 0.05) 2 h later. Maternal T3 remained unchanged. A higher dose of TRH (600 .mu.g) produced comparable results. Maternal administration of TRH (400 .mu.g) 2 h before delivery resulted in significant increases in fetal TSH and T3 over controls (21.1 .+-. 3.7 versus 4.8 .+-. 1.0 .mu.U/ml, and 132 .+-. 12 versus 64 .+-. 9 ng/dl, p < 0.01, respectively). Cord blood hormone levels 12 hours after TRH administration were similar to controls. Higher doses of TRH did not produce further increases in fetal TSH or T3. Control and treated neonates demonstrated similar physiological postnatal increases in TSH and T3, suggesting that prior exposure to TRH did not blunt this response. These data suggest that maternal administration of TRH is an effective way of increasing fetal T3 levels, and that this treatment does not inhibit the postnatal surge is TSH and T3.