[Hashimoto's encephalopathy associated with scleromyxedema: coincidental or the overlapping of two syndromes with a possible autoimmune origin?]. / Asociación de encefalopatía de Hashimoto y escleromixedema: coincidencia o solapamiento de dos síndromes de posible origen autoinmune?

INTRODUCTION: The encephalopathies that may accompany Hashimoto's thyroiditis and scleromyxedema, both of which are diseases that probably have an autoimmune origin, are clinically similar. The presence of both Hashimoto's thyroiditis and scleromyxedema in a patient with encephalopathy led us to compare the clinical symptoms and the different possible mechanisms accounting for the pathology. CASE REPORT: We describe the case of a 54-year-old male who was admitted to hospital because of several occurrences of transient neurological focus that finally developed into a clinical picture of aphasia, acalculia and right homonymous hemianopsia. The patient had previously been diagnosed as suffering from scleromyxedema, which responded poorly to treatment, as well as IgG kappa paraproteinemia and, six months before admission to hospital, Hashimoto's thyroiditis. No abnormalities were found in the complementary tests, except for slightly high protein levels in the cerebrospinal fluid, a diffuse slowing of brain waves in the electroencephalogram and alterations due to thyroiditis and paraproteinemia. Neurological symptoms improved after a few days of corticoid therapy. CONCLUSIONS: The presentation of encephalopathy as a stroke and its excellent response to treatment with corticoids pointed to a case of Hashimoto's encephalopathy, although we cannot completely rule out the possibility of it being a dermato-neuro syndrome, which is associated to scleromyxedema. In this paper we review the different pathological mechanisms proposed for the two clinical entities, as well as the clinical features that are similar in both syndromes and which could be an indication of some common mechanism shared by them.

[Localization of the epileptogenic zone by analysis of electroencephalographic dipole]. / Localización de la zona epileptógena mediante el análisis de dipolos electroencefalográficos.

INTRODUCTION: In partial epilepsy with seizures which are resistant to drug treatment, better results may be obtained with surgery. This follows thorough assessment to identify the area of the brain responsible for the origin of the seizures, or the epileptogenic zone (EZ), and show that surgical operation will not cause neurological or cognitive damage which might handicap the patient. OBJECTIVE: This study analyses the value in diagnosis of electroencephalographic dipoles in delimitation of the EZ in patients with refractory partial epilepsy who are candidates for surgical treatment. PATIENTS AND METHODS: In 43 patients we made EEG recordings whilst at rest with their eyes shut during 15 minutes. The signal was analysed by digital EEG apparatus and a map drawn of cerebral electrical activity based on the maximum average amplitude of the epileptic spikes. The electric dipole equivalent to epileptiform activity between seizures was obtained using the programme for analysis of electroencephalographic sources BESA. The localization of the EZ by means of the dipole was compared with the results of EEG, MR, SPECT and seizure video-EEG using intracranial electrodes. RESULTS: The results of this study show that the dipole model used is highly sensitive for localization of EZ, and in cases in which the dipole and MR coincided, its sensitivity is similar to that of video-EEG during seizures. CONCLUSIONS: The model of dipole used in this study is of great help when indicating surgery for patients with drug-resistant epilepsy.

Biochemical, electrophysiological and neurohormonal studies with B-20991, a selective 5-HT1A receptor agonist.

Different receptor subtypes mediate the effects produced by serotonin (5-HT) in mammals. Besides their proved anxiolytic action, agonists of the 5-HT1A receptor subtype show prospects as antidepressants or neuroprotective agents in case of ischemia. In order to better define the pharmacological profile and determine the selectivity for the 5-HT receptor type, the properties of the new 5-HT1A receptor agonist 2[[4-(o-methoxyphenyl)piperazin-1-yl]-methyl]-1.3-dioxoperhydroimidazo[1.5-a]pyridine (B-20991), an arylpiperazine derivative, have now been further studied. B-20991 was found to antagonize the forskolin-induced increase of cAMP synthesis in a HeLa cell line transfected with the human 5-HT1A in a process sensitive to the selective blocker N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinyl-cyclohexanecarboxamide maleate (WAY 100635). Additionally, B-20991 showed a dose-dependent inhibition of the spontaneous on-going activity of serotonin (5-HT) neurons in the dorsal raphe nucleus in rats, an effect that was reversed by treatment with WAY 100635. This, together with the fact that the hypothermia induced by B-20991 in mice was also antagonized by WAY 100635, suggests that the new compound acts upon somatodendritic 5-HT1A receptors. Additional activation of 5-HT1A postsynaptic receptors was indicated by the increase of corticosterone plasma levels induced by B-20991 in the rat. These results demonstrate that B-20991 is a selective 5-HT1A receptor agonist acting both pre- and postsynaptically, which represents an useful pharmacological tool to study 5-HT1A-receptor-mediated effects.

Monosynaptic Ia pathways at the cat shoulder.

1. The study aimed to describe in cat forelimb and shoulder motoneurones the convergence and projection patterns from large muscle spindle afferents (Ia). In 11 chloralose-anaesthetized cats maximum Ia EPSPs evoked by electrical stimulation of ipsilateral forelimb nerves were obtained in 309 intracellularly recorded alpha-motoneurones. 2. Groups of motor nuclei displayed similar Ia patterns. As in the distal forelimb they were often interconnected by bidirectional pathways, which were used to combine Ia synergistic groups. Three such groups are described at the shoulder. 3. The first group was composed of the main flexors of the scapulo-humeral joint. Regular disto-proximal Ia excitation from elbow extensors (and median afferents) indicates a coupling of flexion in the scapulo-humeral joint to the angular position of the elbow. 4. The second group comprised the outward rotators of the humerus with differentiated Ia convergence onto the different group members. The patterns of Ia excitation received and sent by the group members demonstrate that the outward rotators are incorporated in versatile synergisms and may occupy a central position in steering forelimb movements. 5. The third group was formed by the spinatus muscle and the subscapularis. This arrangement is suggested by the common convergence onto them from the elbow extensors and flexors. The pattern may serve to guide and keep the humeral head in the joint capsule. 6. The Ia synergistic groups receive Ia convergence from muscles acting at distant joints and also project to distant muscles. This is discussed as part of an extended pattern of Ia connections along the forelimb. In this way the shoulder muscles would be incorporated in flexor and extensor oriented synergisms which are needed to co-ordinate the muscular activation along the multijoint forelimb during locomotion. When the shoulder Ia pathways are compared with those in the distal forelimb, organization of the Ia system apparently follows a few basic principles which have adapted to the mechanical situation at the particular joints and their mechanical interaction.