Detection of adrenocortical autoantibodies in Addison's disease with a peroxidase-labelled protein A technique

Adrenocortical autoantibodies (ACA), present in 60-80 percent of patients with idiopathic Addison's disease, are conventionally detected by indirect immunofluorescence (IIF) on frozen sections of adrenal glands. The large-scale use of IIF is limited in part by the need for a fluorescence microscope and the fact that histological sections cannot be stored for long periods of time. To circumvent these restrictions we developed a novel peroxidase-labelled protein A (PLPA) technique for the detection of ACA in patients with Addison's disease and compared the results with those obtained with the classical IIF assay. We studied serum samples from 90 healthy control subjects and 22 patients with Addison's disease, who had been clinically classified into two groups: idiopathic (N = 13) and granulomatous (N = 9). ACA-PLPA were detected in 10/22 (45 percent) patients: 9/13 (69 percent) with the idiopathic form and 1/9 (11 percent) with the granulomatous form, whereas ACA-IIF were detected in 11/22 patients (50 percent): 10/13 (77 percent) with the idiopathic form and 1/9 (11 percent) with the granulomatous form. Twelve of the 13 idiopathic addisonians (92 percent) were positive for either ACA-PLPA or ACA-IIF, but only 7 were positive by both methods. In contrast, none of 90 healthy subjects was found to be positive for ACA. Thus, our study shows that the PLPA-based technique is useful, has technical advantages over the IIF method (by not requiring the use of a fluorescence microscope and by permitting section storage for long periods of time). However, since it is only 60 percent concordant with the ACA-IIF method, it should be considered complementary instead of an alternative method to IIF for the detection of ACA in human sera

Estímulo do eixo hipófise-adrenocortical com o hormônio liberador de corticotrofina (CRH) na síndrome de imunodeficiência adquirida: evidência de ativaçäo do sistema imune-neuroendócrino / Stimulus of hypophyseal-adrenocortical axis with the corticotropin releasing hormone (CRH) in acquired immunodeficiency syndrome: evidence for activation of the immune-neuroendocrine system

Portadores de AIDS podem apresentar alteraçöes primárias e/ou secundárias do eixo hipotálamo-hipofisário-adrenocortical (EHHA), com manifestaçöes clínicas que väo de crises addisonianas a quadros de hipercortisolismo. Objeto. Avaliar o EHHA de 20 pacientes de AIDS e 17 controles normais, mediante testes de estímulo com ACTH exógeno (cosintropina, 250µg IV em bolo, com dosagem de cortisol basal e 60min após) e, subseqüentemente, teste de estímulo com hormônio liberador de corticotrofina ovino sintético (oCRH, 1µg/kg IV em bolo, com dosagens de ACTH e cortisol basais e a intervalos de 15-30min durante duas horas). Resultados. Diferente dos voluntários normais, pacientes de AIDS apresentaram estado de hipercortisolismo basal e após estímulo, tanto com cosintropina como com o CRH; cortisol (em µg/dL, média + or - cosintropina - basal 22,5 + or - 7,1 x 10,6 + or - 3,6 (p < 0,01) e após estímulo, 36,0 + or - 12,8 x 28,3 + or - 7,6 (p< 0,05); teste de oCRH - basal 19,7 + or - 9,0 x 10,1 + or - 3,4 (p < 0,01) e no pico de resposta, 27,5 + or - 8,9 x 18,3 + or 0 5,1 (p < 0,05). Além disso, a secreçäo de ACTH encontrava-se também significantemente mais elevada nos pacientes de AIDS após o teste de estímulo com o CRH; ACTH (em pg/mL) nos pacientes com AIDS x normais: teste de oCRH - basal 42,2 + or - 33,5 x 28,9 + or - 12,7 (NS) e no pico de resposta, 104,7 + or - 62,2 x 59,3 + or - 17,6 (p < 0,05). Conclusöes. Pela condiçäo de estresse continuado, os pacientes de AIDS apresentam estado de hipercortisolismo e de hipersecreçäo de ACTH, revelando resistência ao mecanismo de feedback negativo. Este fenômeno pode ser explicado pela interaçäo do sistema imunológico com o EHHA, com ativaçäo deste eixo pela liberaçäo de linfocinas circulantes que estimulariam, diretamente, hipotálamo e hipófise a produzir CRH e ACTH, respectivamente

Comparative study of two tests of renal diluting ability in Bartter's syndrome

1. Different results concerning distal NaCl reabsorption have been reported for patients with Bartter's syndrome in tests of renal diluting ability. We describe clearance studies performed on 3 patients with Bartter's syndrome using different routes for body fluid content expansion: water was given orally and 0.45 NaCl solution intravenously. The impact of fluid composition was evaluated in one patient who additionally underwent a "reverse test": i.e., intravenous 5 glucose in water and an oral load of 0.45 NaCl solution. 2. Urine flow per ml glomerular filtration rate (GFR) reached higher levels when the iv route was used (20.6 +/- 1.8 vs 11.8 +/- 5.7, P < 0.05). Fractional excretion of Na+, Cl- and osmoles increased during NaCl infusion but not during the oral load. Also, distal delivery of solute increased and was greater than that observed in the oral test (21.9 +/- 5.5 vs 11.4 +/- 2.1, P < 0.05). 3. In contrast, fractional distal chloride reabsorption in the iv test reached subnormal values which were lower than in the oral load test (65.0 +/- 11.2 vs 86.8 +/- 11.0, P < 0.05). A positive correlation was observed between distal delivery and Cl- fractional excretion (r = 0.87; P < 0.005). In one patient, the 5 glucose infusion resulted in greater urine flow and distal delivery when compared to distilled water or 0.45 NaCl taken orally (28.1 vs 13.3 ml/min and 27.3 vs 12.8, respectively). These values were as high as those observed during iv administration of hypotonic saline. 4. The iv route was always associated with lower rates of fractional distal chloride reabsorption (70.7 vs 89.1) regardless of the solute composition and should be recommended when testing the renal diluting ability of patients suspected of Bartter's syndrome.

Different effects of pyridostigmine on growth hormone (GH) response to GH-releasing hormone in endogenous and exogenous hypercortisolemic patients

1. Somatostatin may play a role in the inhibition of growth hormone (GH) response to GH-releasing hormone (GHRH) in hypercortisolism. To examine this hypothesis we studied the effect of pyridostigmine, a cholinergic agonist that decreases hypothalamic somatostatin, on the GH response to GHRH in 8 controls, in 6 patients with endogenous hypercortisolism (3 with Cushing's disease and 3 with adrenal adenomas) and in 8 patients with exogenous hypercortisolism (lupus erythematosus chronically treated with 20-60 mg/day of prednisone). Each subject received GHRH(1-29)NH2,100 micrograms iv twice, preceded by pyridostigmine (120 mg) or placebo, orally. 2. The GH response to GHRH was significantly blunted in all hypercortisolemic patients compared to controls both after placebo (GH peak, 5.8 +/- 1.6 vs 46.2 +/- 15.9 micrograms/l, mean +/- SEM) and after pyridostigmine (15.7 +/- 5.6 vs 77.2 +/- 19.8 micrograms/l). 3. The GH response was absent in endogenous hypercortisolemic patients compared to the exogenous group, both after placebo (2.2 +/- 0.3 vs 8.5 +/- 2.4 micrograms/l) and after pyridostigmine (4.9 +/- 2.5 vs 23.8 +/- 8.7 micrograms/l). The GH release after GHRH/pyridostigmine for the exogenous group was similar to the response of controls treated with GHRH/placebo. 4. These results confirm that the GH response to GHRH is blunted in hypercortisolism, although more pronounced in the endogenous group. Pyridostigmine partially reversed this inhibition in the exogenous group. Therefore, somatostatin may play a role in the inhibition of GHRH-induced GH release in exogenous hypercortisolemic states

Tomografia computadorizada das adrenais na investigacao da sindrome de Cushing. / Computerized tomography of adrenal glands in the research of Cushing's syndrome

A tomografia computadorizada tem demonstrado grande utilidade no diagnostico de tumores adrenais.Dez pacientes com sindrome de Cushing foram submetidos a tomografia computadorizada das adrenais utilizando-se um aparelho G.E. 8.800 CT/T BodyScanner (Matriz 320 x 320). O diagnostico tomografico de tumor adrenal unilateral em 4 pacientes foi confirmado pelos achados cirurgicos (2 adenomas e 2 adenocarcinomas). Nos demais pacientes, nos quais o exame nao evidenciou a presenca de massas, ambas adrenais eram bem visualizadas e apresentavam forma conservada. Nesses pacientes, mensuracao das adrenais na tomografia (comprimento, largura e espessura) revelou adrenais de tamanho normal (n = 1) ou aumentadas (n = 5). O diagnostico de hiperplasia adrenal nesses pacientes foi estabelecido atraves de adrenalectomia (n= 4) ou cirurgia hipofisaria e evolucao (n= 2). Esses resultados atestam a utilidade da tomografia computadorizada no estudo anatomico das adrenais em pacientes com sindrome de Cushing

Padrao de resposta da 17-alfa-hidroxiprogesterona ao estimulo com ACTH em heterozigotos para deficiencia da enzima 21-hidroxilase. / Response standard of 17-alpha hydroxyprogesterone to ACTH stimulation in heterozygotes for 21-hydroxylase deficiency

A resposta de 17-alfa-OHD e cortisol ao estimulo com ACTH em individuos heterozigotos (HTZ) e homozigostos para hiperplasia adrenal congenita por deficiencia da 21-hidroxilase foi comparada com individuos controles. Os niveis basais ou estimulos de conrtisol nao apresentaram nenhuma diferenca entre os HTZ e os controles. A 17-alfa-OHP, por sua vez, nao apresentou diferenca em condicoes basais porem 60 minutos apos estimulos houve um incremento dignificativamente maior que os controles.A relacao 17-alfa-OPH/cortisol, apos estimulo, foi significativamente maior nos HTZ Concomitantemente, foram colhidas amostras de sangue por aspiracao continua que surgeriram uma taxa de incremento mais elevado no intervalo de 0-15 minutos, antingido os valores mais altos no intervalo entre 30-60 minutos.Nas duas metodologias de coleta, observou-se uma resposta de 17-alfa-OHP apos estimulo nitidamente superior nos HTZ que no grupo controle, embora, devido a faixa de superposicao entre os 2 grupos, nao autoriza a padronizacao do teste para detectar portadores de heterozigose na populacao geral