Impact of long-term administration of amiodarone on the thyroid function of patients with Chagas' disease.

The effect of long-term treatment with amiodarone on patients with Chagas' disease has seldom been reported. This nonrandomized observational study attempted to analyze the follow-up of patients with Chagas' disease regarding their clinical evolution, thyroid dysfunction, and goiter. We compared 72 patients with long-term use (11 +/- 5 years) of amiodarone, including 22 patients who developed goiter, to 33 patients who did not use amiodarone, followed-up for 2 to 20 years (7 +/- 11 years). Follow-up of 72 patients for 9 +/- 5.4 years with periodic cardiac and thyroid function evaluations showed that only 26 maintained normal serum thyrotropin (TSH) levels; 24 presented with elevated levels; 4 had low levels, and 18 patients presented with fluctuations of TSH level. Among the 22 patients with goiter, only 3 (14%) patients maintained normal TSH, 8 (36%) had elevated TSH, 2 (9%) had low TSH, and 9 (41%) patients presented with fluctuating serum TSH levels. Most individuals remained clinically euthyroid with no evidence of cardiac impairment that could be attributed to thyroid dysfunction and the arrhythmias were adequately controlled by amiodarone. We suggest that amiodarone treatment may be continued for patients with Chagas' disease with arrhythmias, even in those who develop thyroid function abnormalities or goiter.

Hypothalamic response to experimental allergic encephalomyelitis: role of substance P.

Adjuvant-induced arthritis (AA) is thought to be a model for experimental chronic stress that has as main features decreased adrenocorticotropin hormone (ACTH) plasma levels and a rise in median eminence content of arginine vasopressin (AVP) due to the activity of substance P. In experimental allergic encephalomyelitis (EAE), another chronic stress model, the role of substance P action is not clear. In this paper we tried to clarify the role of substance P in Lewis rats, which are susceptible to this disease. EAE was induced using myelin basic protein plus complete Freund's adjuvant injected into the hind limbs. One day later injections of an antagonist to substance P (RP 67580), saline, and substance P were administered daily for 12-14 days through a stainless steel cannula into the lateral ventricle of the brain, and then the rats were killed. The rats were divided into groups of controls, sham, diseased controls (no intracerebroventricular injections) and EAE (injected intracerebroventricularly). Plasma was used for the quantification of ACTH and corticosterone but not AVP which was assayed in hypothalamic median eminence extracts. In noninjected diseased rats the plasma levels of ACTH and corticosterone were significantly higher than in noninjected control rats, whereas the AVP concentrations in the median eminence were unchanged. The substance P antagonist did not affect the levels of these hormones in plasma or the median eminence. Substance P decreased the plasma levels of ACTH and corticosterone but did not increase the median eminence content of vasopressin. Administration of the antagonist 30 min before an equivalent dose of substance P increased the plasma levels of the two hormones, but did not change the content of AVP. Based on the lack of response to the antagonist RP 67580 we suggest that the substance P has different roles in EAE and AA at least in the later stages of EAE (after 11 days of immunization).

Serum cytokines in chronic Chagas' disease

Estudamos os níveis séricos da lL-2, IFN-gama e do TNF-alfa de portadores da doença de Chagas em suas diferentes formas clínicas, compensados e descompensados. As citocinas medidas nos 91 pacientes com a forma crônica da doença näo diferiram dos níveis de 13 indivíduos controle. Näo houve diferença estatística entre os 17 portadores da forma indeterminada da doença e os portadores de cardiopatia insipiente (n = 4), de cardiopatia bem estabelecida (n = 62), da forma digestiva (n = 4) ou da forma mista (n = 4) da doença. Os níveis séricos de TNF foram indetectáveis e IFN-gama näo diferiu nas diferentes formas clínicas ou com a severidade da doença. No entanto, encontramos níveis mais elevados de IL-2 nos 25 pacientes näo-contrololados do que nos 66 pacientes bem compensados (p < 0,001). Sugerimos que a dosagem de IL-2 possa servir como indicadora da necessidade de terapêuticas mais agressivas nestes pacientes