[Idiopathic hypertrophic pachymeningitis: a diagnostic dilemma]. / Paquimeningitis hipertrófica idiopática: un dilema diagnóstico.

INTRODUCTION: Idiopathic hypertrophic pachymeningitis (IHP) is a rare fibrosing inflammatory process of unknown pathogenesis that causes diffuse thickening of the duramater. In spite of the fact that this pathological entity has been linked to specific etiological agents such as syphilis, tuberculosis, mycosis and sarcoidosis, In recent years there has been an increase in the number of patients with IHP of undetermined cause. CASE REPORT: 58 year-old female with a long date history of oppressive headaches, frontally located at first, and later generalized, accompanied by weakness and asthenia; urinary incontinence, dizziness, vomiting, and gait ataxia. Physical examination revealed bilateral cerebellar signs, and optic atrophy. Magnetic resonance displayed a diffuse thickening of the falx cerebrii, and cerebellar tentorium, hypointense in T1 and T2- weighted images, and markedly enhanced following administration of intravenous Gd-DTPA. A biopsy obtained from the falx revealed conspicuous fibrosis, and focal chronic inflammatory mononuclear infiltrate. Complementary exams carried out in order to reveal a specific etiologic agent were negative. CONCLUSION: Due to the variable clinical presentation, and the difficulty to establish the etiology of the pathological process, to make the diagnosis of IHP usually represents a true dilemma. This diagnosis is often made by exclusion.

[Cerebrovascular disease: its relationship with cardiovascular and renal pathology in 134 clinical autopsies]. / Enfermedad cerebrovascular: su relación con cardiovasculopatías y nefropatías en 134 necropsias clínicas.

OBJECTIVE: To establish the relationship between cardiopathy and chronic nephropathy, and cerebral vascular pathology in clinical necropsies performed in adult patients. MATERIAL AND METHODS: The protocols of 861 clinical autopsies done during the lapse 1990-2000 were reviewed, of these, 134 cases with diagnosis of cerebrovascular disease (CVD) were selected. Analyzed features included: neuropathological study of CVD, renal and cardiovascular pathology, and cause of death. RESULTS: CVD represented 15.5% of all autopsies done during the study period. Ischemic CVD constituted 56.7% of the cases, whereas cases of hemorrhagic CVD accounted for 43.3% of the total. Causes included arterial hypertension (33%), atherosclerosis (19%), emboli and vascular malformations (13% each, respectively), coagulopathies (8%), angeiitis (4%), tumors (1%), and unknown origin (11%). Ischemic CVD was caused by atherosclerosis in 34.2% of the cases, lacunar infarcts in 32.8%, of embolic cause in 14.4% of the cases, angeiitis in 1.3%, and of unknown origin in 17.1% of the cases. Hemorrhagic CVD presented as intraparenchymal hematoma in 50% of the cases, as sub-arachnoid hemorrhage in 28%, as disseminated petechial hemorrhages in 19%, and intraventricular in 3% of the cases. Ischemic CVD was associated with hypertensive cardiopathy in 86.5% of the cases, and with nephrosclerosis in 51.3%, whereas hemorrhagic CVD was seen associated with the same pathological entities in 86.2% and 29.3% of the cases, respectively. Cerebral herniation was the cause of death in 2.6% of the patients with ischemic CVD, and in 74.1% of the patients with hemorrhagic CVD. CONCLUSIONS: CVD was associated with a high frequency of intercurrent pathological processes, namely hypertensive cardiopathy, atherosclerosis, nephroscleroisis, and other chronic nephropathies, that eventually interact, and constitute well known predisposing and/or concomitant factors to the cerebrovascular event

[Non neoplastic space occupying lesions mimicking central nervous system tumors]. / Lesiones ocupantes de espacio no neoplasicas que simulan tumores del sistema nervioso central.

OBJECTIVE: To establish the frequency and nature of space occupying lesions of the central nervous system (CNS) that mimic neoplastic growths. PATIENTS AND METHODS: We reviewed the clinical records, imaging and neuropathological studies of patients operated in different hospitals of Maracaibo, Venezuela during the period January 1 1996 July 31 2002. These patients had a pre operative diagnosis of CNS tumor, and their definitive diagnosis was non neoplastic disease. RESULTS: The 33 cases of expansive, non neoplastic growths represented 8% of 408 CNS lesions diagnosed during the study period. Approximately two thirds of the cases (63,36%) consisted of either inflammatory or vascular lesions, whereas the rest of the cases grouped miscellaneous conditions. CONCLUSIONS: Even though it is not frequent that non neoplastic lesions of the CNS mimic expansive growths of neoplastic nature, on occasions the clinical and neuroimaging features of both groups of entities are remarkably similar.

[Characterization of neuronal ceroid lipofuscinosis in Venezuelan children]. / Caracterización de la ceroidolipofuscinosis en niños venezolanos.

INTRODUCTION: Neuronal ceroid lipofuscinosis (NCL), represents a group of inherited neurodegenerative disorders. Based on the age of the patient at onset, clinical course and ultrastructural morphology it has been identified three clinical types for the pediatric group: 1) Infantile NCL (INCL); 2) Late infantile NCL (LINCL); and 3) Juvenile NCL (JNCL). Other variants or atypical forms represent around 20% of the NCL in different populations. Genetic advances have made possible a better characterization, diagnostic and classification of these disorders. CASE REPORTS: We present the clinical, neurophysiological, neuroradiological, and morphological data from 6 patients with NCL, who were assessed at the pediatric neurology department of the Hospital Universitario de Maracaibo during a ten years period (1993 2003). All 6 cases corresponded with the late infantile form. Age of onset ranged form 2 to 5 years. For most of the patients initial symptoms included seizures, psychomotor delay, accompanied by macular degeneration and optic atrophy. The EEG was characterized by high voltage spikes elicited by low frequency photic stimulation, in 5 cases. Neuroimaging findings were characteristic of the late infantile form of the NCL. In three patients a decreased intensity of signal was seen in the thalami and putamen on T2-weighted images. The ultrastructural examination of the samples obtained through a biopsy showed curvilinear bodies in all patients. CONCLUSION: There is not epidemiological data of the NCL in Venezuela; it is presumed the presence of clinical forms and variants in the pediatric group. This first study could contribute to the knowledge and a better research of this group of disorders in our population.

[Estimations of the prevalence of attention deficit hyperactivity disorder in Marabino children]. / Estimaciones de la prevalencia del trastorno por déficit de atención-hiperactividad en niños marabinos.

AIMS: This study reports the findings of research aimed at determining the rate of prevalence of attention deficit hyperactivity disorder (ADHD) in children of school age. SUBJECTS AND METHOD: The epidemiological study was conducted using a community sample extracted by means of multi stage stratified sampling according to socio economic level and schooling and consisted in 1,141 children of both sexes of school age from the city of Maracaibo. The revised Conners scales were used to collect data. RESULTS: The estimated prevalence of ADHD was 7.19% and we also obtained 0.35% for the hyperactive type, 1.14% for the disattentional subtype, and 5.70% for the combined type. Contrary to what was expected, prevalence was higher for females. It was found that 7.45% of the general sample scored higher on the academic problems scales, whereas for the sample identified as having ADHD, academic problems were 50% and the comorbidity between ADHD and academic problems was confirmed. CONCLUSIONS: The estimates for prevalence found in this study are consistent with those reported in the literature, which suggests that ADHD is a valid diagnosis for Marabino children.

Serial MRI findings in the Costa Rican variant of neuronal ceroid-lipofuscinosis.

Widespread cerebral atrophy and basal ganglia involvement are highly suggestive imaging features of the variants of late infantile type neuronal ceroid-lipofuscinosis. In the presence of clinical findings indicative of neuronal ceroid-lipofuscinosis, neuroimaging procedures are highly recommended to differentiate the variants from classic late infantile neuronal ceroid-lipofuscinosis. The clinical features and follow-up magnetic resonance imaging studies in a patient with the Costa Rican variant of late infantile neuronal ceroid-lipofuscinosis is presented. These procedures were of the utmost importance to observe the progression of the neurologic ailment and the extent of the cerebral and cerebellar abnormalities.

[The classical clinical and neuroimaging features of meningiomas are mimicked by other intracranial, supratentorial expansive lesions]. / Las características clínico-imaginológicas clásicas de los meningiomas son imitadas por otras lesiones expansivas.

OBJECTIVE: To analyze the surgical neurology cases in which both the clinical and neuroimaging features suggested supratentorial meningioma, and resulted in different entities from the neuropathological point of view. PATIENTS AND METHODS: The clinical histories of patients harboring intracranial, supratentorial mass lesions diagnosed as meningioma operated in different hospitals of Maracaibo, Venezuela, during the period 1993-1997 were reviewed. RESULTS: Our analysis revealed 15 cases with different neuropathological diagnosis. They were distributed as follows: three cases of hemangiopericytoma, two cases each of anaplastic ependymoma, metastatic carcinoma, and solitary intracranial plasmacytoma, and one case each of plasma cell granuloma, pleomorphic xanthoastrocytoma, chondroma, actinomycetoma, meningeal fibroma and chronic inflammation not otherwise specified. CONCLUSION: A heterogeneous group of intracranial, supratentorial expansive mass lesions can masquerade as meningiomas both from the clinical and neuroimaging points of view.

Extraventricular cerebral anaplastic ependymomas.

BACKGROUND: Anaplastic ependymomas are considered to be uncommon cerebral tumors by most authors. We have had the opportunity to study 34 cases of such lesions in 13 years. METHODS: 34 cases of anaplastic ependymoma operated in different hospitals of Maracaibo, Venezuela, during the period of 1983-1995 were analyzed. Cases of ependymoblastoma were excluded. RESULTS: Adult patients made up most of the present series. All patients harbored supratentorial growths in locations distant from the ventricular system. The microscopic pattern was of limited value to establish prognosis, for there was no constant correlation between the histologic features and tumor relapse; only in sporadic cases in which high cell density and conspicuous mitotic activity were maximally expressed, did tumor relapse occur shortly after removal of the lesion. CONCLUSION: This type of paradoxical behavior being the rule makes all attempts at predicting prognosis in these entities a disappointing task.

[Venezuelan equine encephalitis. 1995 outbreak: clinical profile of the case with neurologic involvement]. / Encefalitis equina venezolana. Epidemia de 1995: perfil clínico de los casos con compromiso neurológico.

INTRODUCTION: Venezuelan equine encephalitis virus has caused periodic epidemics and epizootics in the American continent since the 1920s. Such events have been profusely documented from the epidemiologic point of view, however, reports concerning the clinical features of this disease are rather scarce. OBJECTIVE: To analyze the clinical characteristics evidenced by Venezuelan equine encephalitis patients from Zulia state (western Venezuela) studied during the outbreak that occurred in Colombia and Venezuela in 1995. These cases, classified as complicated, were hospitalized at the Hospital Universitario de Maracaibo, state of Zulia, Venezuela. PATIENTS AND METHODS: The clinical charts of 313 Venezuelan equine encephalitis patients hospitalized during the period January 1st 1995-March 31st 1996 were reviewed. These cases accounted for 2.82% of 11,072 patients that were medically assisted during the outbreak. The following variables were analyzed: age, gender, signs and symptoms, contact history, complications and evolution. RESULTS: Intracranial hypertension signs became eloquent in 55.9% of these patients. Neurologic complications were represented by two cases of cerebellitis, two cases of meningoencephalitis and one case of encephalomyelitis. The mortality rate was 1.7%. CONCLUSION: Our results corroborate the benign evolutionary profile that is typical of this entity.

GABAergic neurons and circuits in the pretectal nuclei and the accessory optic system of mammals.

Two classes of GABAergic cell bodies have been described. They probably can be divided into GABAergic local interneurons and GABAergic projection neurons. GABAergic cell bodies receive few terminals which is in contrast to non-GABAergic somata, which receive many synaptic contacts. GABAergic dendrites that originate from GABAergic cell bodies, however, receive numerous terminals, both GABAergic and nonGABAergic. It can therefore be concluded that somatic inhibition is not present on GABAergic neurons, but does occur on nonGABAergic neurons. Furthermore, dendrites traverse large parts of the NOT/DTN forming a complex network that enables sampling and integration from a wide area. The projection to the IO is not GABAergic itself, but cells projecting to the IO receive a substantial GABAergic input, that probably originates in part from the MTN. Further investigation on the distribution of this input over a completely identified neuron would provide the quantitative data that are required to verify the above mentioned hypothesis. A GABAergic projection that originates in the pretectal nuclei is directed towards the superficial layers of the SC in the cat (Appell and Behan, 1990) and rat (Van der Want et al., 1991). A second GABAergic projection derives from the pretectum and reaches the LGN (Cucchiaro et al., 1991). Whether this projection originates from the same GABAergic cell bodies that project to the SC and the LGN or is derived from different populations remains to be determined. The ultrastructural studies of the NOT/DTN complex have shown that GABAergic terminals with different morphological characteristics are present and that the GABA positive F and P terminals are widely distributed over somata and the adjacent neuropil. The P terminals probably originate from dendrites of GABAergic interneurons while the F types originate from GABAergic projection and interneurons (Van der Want and Nunes Cardozo, 1988). One of these sources is located in the MTN differ from the intrinsic GABAergic terminals with respect to their relation to R terminals. GABAergic MTN terminals were never observed to receive R terminal input. This is in contrast with other GABAergic terminals which frequently do receive direct contact from R terminals. Within glomeruli triadic arrangements, formed by a single retinal terminal, a dendritic profile and second axonal profile dendritic profile and second axonal profile synapsing with the dendrite, were frequently encountered in the OPN (Campbell and Lieberman, 1985), but only occasionally in the NOT/DTN (Nunes Cardozo and Van der Want, 1987).(ABSTRACT TRUNCATED AT 400 WORDS)

GABA immuno-electron microscopic study of the nucleus of the optic tract in the rabbit.

The pretectal nucleus of the optic tract (NOT) was investigated immunocytochemically with an antiserum against gamma aminobutyric acid (GABA) employing the pre-embedding peroxidase antiperoxidase technique at the light microscopic level and the postembedding colloidal gold technique at the electron microscopic level. GABA immunoreactivity was observed in cell bodies of different sizes and as punctate structures in the neuropil. In the electron microscope, besides immunoreactive dendrites, four different types of terminals were found to be GABA-immunopositive; three types of terminals with clustered and flattened vesicles (F-profile) and a fourth type with pleomorphic vesicles, presumably of dendritic origin (P-profile). Both P- and F-profiles formed symmetrical synapses with dendritic profiles arranged in clusters ensheathed by glial elements. GABA-immunopositive terminals were observed in synaptic contact with somata and retinal terminals (R-profiles) that were always GABA-immunonegative. Some GABA-immunopositive somata showed presynaptic contacts with dendrites. The presence of GABA in numerous distinct elements in the NOT and the diversity in labeled somata and terminals demonstrate the importance of the inhibitor neurotransmitter in the NOT and suggest that its function is not limited to interneurons.

Synaptic organization of the nucleus of the optic tract in the rabbit: a combined Golgi-electron microscopic study.

The organization of the nucleus of the optic tract was investigated with light and electron microscopy in combination with Golgi impregnation. In Golgi material, neurons ranged in size from 10 to 25 microns with three to seven principal dendrites extending predominantly parallel to the fibres of the optic tract, irrespective of their location within the nucleus. In some areas dendrites extended into the neuropil of the adjacent dorsal terminal nucleus of the accessory optic system and the posterior pretectal nucleus. Occasionally spines and appendages were observed. The fine structure of the nuclei, perikarya and the dendritic arborization did not allow a well-defined distinction between interneurons and projection neurons. The synaptic organization of the nucleus of the optic tract showed great resemblance to the neuropil of the lateral geniculate nucleus and the superior colliculus. Similar types of presynaptic terminals were noticed: (i) R-terminals were either large and scalloped or small and regular in outline with spherical vesicles and electron-lucent mitochondria, and showed asymmetric contact zones; (ii) F-terminals with flattened vesicles, opaque mitochondria and symmetric contact zones; (iii) RLD-terminals with spherical vesicles and electron-dense mitochondria and asymmetric contact zones; (iv) P-terminals with pleomorphic vesicles and electron-lucent or opaque mitochondria and asymmetric synaptic thickenings. These different types of terminal were found isolated in the neuropil or in clusters of synapses. The most striking differences between the nucleus of the optic tract and the lateral geniculate nucleus were the relative scarcity of F-terminals in the clusters, the paucity of triadic arrangements and the relatively small size of the R-terminals. The differences in ultrastructure may be related to retinal W-type ganglion cells, which form the main retinal input to the nucleus of the optic tract and could also be related to the physiologically identified direction-selective units within the nucleus of the optic tract.

Variations in presynaptic grid size in the granular and molecular layer of the cerebellar cortex of the cat. I. A quantitative ultrastructural study on semithin E-PTA sections.

The size distribution of synapses in the cerebellar cortex of the cat was defined on 0.5-micron semithin sections stained with ethanolic phosphotungstic acid (E-PTA). The surface area (SA) of synaptic grids was measured and the number of dense projections per grid (NDP) was counted. The results show large differences in mean values between molecular and granular layer. Within the molecular layer the differences in mean values at different levels below the pial surface were small; however, the frequency distributions differed significantly. In the granular layer a confined unimodal frequency distribution of SA and NDP was observed (mean NDP, 7.02 +/- 0.10), in the molecular layer a considerable variation in the size of the synaptic discs was observed (mean NDP, 20.40 +/- 0.43). Only a small percentage of the synaptic discs have less than 5 or more than 47 DPs. The sharply defined differences in synaptic size between the granular and molecular layer and the smaller differences within the granular and molecular layer are discussed in the context of the congruity hypothesis of Chan-Palay.