Browsing by Author "LOPEZ, JM"

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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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    AUTOIMMUNE THYROID-DISEASE IN THE PUERPERIUM - PREDICTIVE VALUE OF THYROID ENLARGEMENT AND RELATED HORMONAL CHANGES OCCURRING DURING PREGNANCY
    (1990) FARDELLA, C; LOPEZ, JM; VALDES, ME; NUNEZ, M; MIRANDA, M
    The incidence of goiter detected during pregnancy and its significance as an indicator of autoimmune thyroid disease after delivery was investigated in a sample of 707 pregnant women (81% in their 2nd trimester of gestation). Goiter was detected in 106 subjects (15%). Blood T4, T3, TSH, free T4 index (FT4), antimicrosomal antibodies (AMA) and urinary iodine excretion were measured in these women and in a control group of gravidas without goiter. These measurements were repeated at 1 and 3 months after delivery. Compared with controls during pregnancy, subjects with goiter had lower FT4I values (11.0 .+-. 2.8 vs 9.0 .+-. 1.8; p < 0.01) and higher TSH values (2.9 .+-. 0.6 .mu.U/ml vs 4.2 .+-. 2.1 .mu.U/ml; p < 0.01). In contrast, T4, T3, AMA and urinary iodine excretion values were similar in both groups. In subjects with goiter FT4I values increased over pregnancy levels at 1 month (11.2 .+-. 2.0; p < 0.05) and 3 months (14.0 .+-. 3.0; p < 0.05) after delivery; in 29% a biochemical hyperthyroidism (FT4I > 13.5) was detected. During the same period TSH values decreased significantly (1 month: 1.9 .+-. 0.7 .mu.U/ml; p < 0.05; 3 months: 2.7 .+-. 3.0 .mu.U/ml; p < 0.05). Frequency of positive AMA increased from 8.6% during pregnancy up to 32.1% in the post-delivery period (p < 0.01). In the control groups no variation in the FT4I, TSH or AMA were observed after delivery. These results indicate that goiter during pregnancy is common in Chilean gravidas and that it has predictive value for the appearance of autoimmune thyroid disease after delivery.
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    CONGENITAL 11-BETA-HYDROXYSTEROID DEHYDROGENASE-DEFICIENCY ASSOCIATED WITH JUVENILE HYPERTENSION - CORTICOSTEROID METABOLITE PROFILES OF 4 PATIENTS AND THEIR FAMILIES
    (1985) SHACKLETON, CHL; RODRIGUEZ, J; ARTEAGA, E; LOPEZ, JM; WINTER, JSD
    Four children with 11 .beta.-hydroxysteroid dehydrogenase deficiency are described. All patients had severe hypertension, hypokalemia, and low plasma aldosterone and renin activities. Two of the patients were siblings and 2 were unrelated. The most noticable biochemical feature of these individuals was the extremely low excretion of cortisol metabolites containing on 11-carbonyl group compared to the excretion of the 11 .beta.-hydroxyl containing metabolites. Although this condition is readily diagnosed in affected individuals by urinary steroid analysis, carriers of the defect do not differ from normal in their urinary steroids. Both parents of the affected siblings had normal 11-oxo-steroid/11 .beta.-hydroxysteroid ratios under baseline conditions and the lesions could not be revealed by ACTH administration.
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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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    GROWTH-HORMONE (GH) RECEPTOR ANTIBODIES WITH GH-LIKE ACTIVITY OCCUR SPONTANEOUSLY IN ACROMEGALY
    (1992) CAMPINO, C; SZECOWKA, J; LOPEZ, JM; MULCHAHEY, J; SERONFERRE, M
    Previous studies in our laboratory have identified a portion of big-big GH as actually being anti-GH receptor immunoglobulins. We now report the isolation of two types of anti-GH receptor antibodies from the serum of active acromegalic patients. One of them (patient A) interferes with the human GH RIA, thus overestimating the real plasma GH values. The other type of immunoglobulin G (IgG; patient B) was detected in an acromegalic patient with almost normal immunoreactive GH level. The main aim of the present study was to explore whether these anti-GH receptor IgGs possess GH-like biological activity. The IgGs of both patients were isolated by chromatography on Sephadex G-100 and then on protein-A-Sepharose. In the bioassay, cultured Nb2 lymphoma cells were incubated with hGH standards and serial dilutions of the purified IgGs, and cell proliferation was used as a measure of biological activity. The IgGs of both patients showed GH-like bioactivities, which, when calculated as equivalents of human GH, correspond to approximately 260 and 120-mu-g/L, respectively. The results suggest that biologically active anti-GH receptor antibodies may contribute in the pathology of some cases of acromegaly.
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    PLASMA-ALDOSTERONE RESPONSE TO ANGIOTENSIN-11 AND KCL INFUSIONS IN HYPOPITUITARY PATIENTS
    (1980) LOPEZ, JM; RODRIGUEZ, JA; MARUSIC, ET
    The acute adrenal response to KCl and angiotensin II (A II) infusions was studied in hypopituitary patients and compared with normal subjects. The peripheral plasma levels of aldosterone (PAC), cortisol, K and plasma renin activity, were measured at 0900 h and after 60 and 120 min of infusion. All subjects were recumbent and under balance conditions, receiving a daily dietary intake of 180 mmol of Na and 80 mmol of K. Basal PAC in hypopituitary patients was not significantly different from that observed in the control group. Both normal and hypopituitary patients respond to A II infusion with significant increments. Under KCl stimulus the PAC response in hypopituitary patients was only observed when cortisol (20 mg) was given 2 h prior to the infusion. When cortisol replacement was omitted the response to KCl was not detected. These results suggest a permissive role of cortisol on glomerulosa response to K.
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    RENIN-SECRETING TUMOR - CASE-REPORT
    (1980) VALDES, G; LOPEZ, JM; MARTINEZ, P; ROSENBERG, H; BARRIGA, P; RODRIGUEZ, JA; OTIPKA, N
    Renin-secreting tumor, though rare, should be considered in assessing severe hyperreninemic, hypertensive patients. An 18-yr-old girl with hypokalemic hyperreninemic hyperaldosteronism was studied. No angiographic lesion was detected. The plasma renin activity (PRA) of the right/left renal vein was 7.3. With a presumptive diagnosis of renin-secreting tumor (RST), the patient was operated on, and a cortical nodule was found on the right lower pole. Partial nephrectomy was followed by a rapid fall in PRA (half-life, 33-44 min) and normalization of blood pressure (BP). At 3 1/2 mo. postoperatively, the patient showed normotension, normopokalemia, normal aldosterone and slightly elevated PRA unresponsive to postural changes and furosemide treatment. Tumoral PRA secretion responded to postural stimulus, spironolactone use and nitroprusside-induced hypotension. Neither the high aldosterone excretion nor hyperreninemia decreased after 3 days of DOCA [deoxycorticosterone acetate]; this agrees with a previously reported case, suggesting the usefulness of this test in the diagnosis of RST.