Detection of the antiviral activity of epicatechin isolated from Salacia crassifolia (Celastraceae) against Mayaro virus based on protein C homology modelling and virtual screening.

Mayaro fever, caused by Mayaro virus (MAYV) is a sub-lethal disease with symptoms that are easily confused with those of dengue fever, except for polyarthralgia, which may culminate in physical incapacitation. Recently, outbreaks of MAYV have been documented in metropolitan areas, and to date, there is no therapy or vaccine available. Moreover, there is no information regarding the three-dimensional structure of the viral proteins of MAYV, which is important in the search for antivirals. In this work, we constructed a three-dimensional model of protein C of MAYV by homology modelling, and this was employed in a manner similar to that of receptors in virtual screening studies to evaluate 590 molecules as prospective antiviral agents. In vitro bioassays were utilized to confirm the potential antiviral activity of the flavonoid epicatechin isolated from Salacia crassifolia (Celastraceae). The virtual screening showed that six flavonoids were promising ligands for protein C. The bioassays showed potent antiviral action of epicatechin, which protected the cells from almost all of the effects of viral infection. An effective concentration (EC50) of 0.247 µmol/mL was observed with a selectivity index (SI) of 7. The cytotoxicity assay showed that epicatechin has low toxicity, with a 50% cytotoxic concentration (CC50) greater than 1.723 µmol/mL. Epicatechin was found to be twice as potent as the reference antiviral ribavirin. Furthermore, a replication kinetics assay showed a strong inhibitory effect of epicatechin on MAYV growth, with a reduction of at least four logs in virus production. Our results indicate that epicatechin is a promising candidate for further testing as an antiviral agent against Mayaro virus and other alphaviruses.

Mesembrinellinae (Diptera: Calliphoridae) to edge effects in the Tinguá Biological Reserve, Rio de Janeiro, Brazil.

In this study we describe the diversity of Mesembrinelinae in a biological reserve in the city of Nova Iguaçu, State of Rio de Janeiro. Traps containing sardines were distributed seasonally, at four sites: Site A (22° 58.788' S, 43° 43.459' W), in a forest edge, and sites B (22° 58.523' S, 43° 44.540' W), C (22° 58.350' S, 43° 44.678' W), and D (22° 34.865' S, 43° 27.063' W), located 1,000 m, 500 m, and 2,000 m respectively, inwards from the edge. A total of 2,150 individuals of Mesembrinellinae were collected, representing ten species. Laneela nigripes Guimarães, 1977 was the most abundant species, followed by Mesembrinella bellardiana Aldrich, 1922, Eumesembrinella cyaneicincta (Surcouf, 1919) and Mesembrinella semihyalina Mello, 1967. These species were common and constant during the study period. Mesembrinella batesi Aldrich, 1922, Eumesembrinella quadrilineata (Fabricius, 1805) and Huascaromusca aeneiventris (Wiedmann, 1830) were the less abundant flies, being considered rare and accidental. Eumesembrinella besnoiti (Seguy, 1925) was rare and accessory. Eumesembrinella cyaneicincta, M. bellardiana, M. semihyalina and M. bicolor were mostly collected in site B, while L. nigripes was mostly collected in site C. The edge effect was not evident since the four sites showed similar populations. Site B showed a strong positive relationship between abundance and richness, in site C the correlation was positive and weak, and there was no correlation in A and D. The highest abundance of specimens was recorded during autumn and winter. These flies occurred from the edge up to 2,000 m inside the forest.

Mesembrinellinae (Diptera: Calliphoridae) to edge effects in the Tinguá Biological Reserve, Rio de Janeiro, Brazil / Mesembrinellinae (Diptera: Calliphoridae) na Reserva Biológica do Tinguá, Rio de Janeiro, Brasil

Abstract In this study we describe the diversity of Mesembrinelinae in a biological reserve in the city of Nova Iguaçu, State of Rio de Janeiro. Traps containing sardines were distributed seasonally, at four sites: Site A (22° 58.788’ S, 43° 43.459’ W), in a forest edge, and sites B (22° 58.523’ S, 43° 44.540’ W), C (22° 58.350’ S, 43° 44.678’ W), and D (22° 34.865’ S, 43° 27.063’ W), located 1,000m, 500m, and 2,000m respectively, inwards from the edge. A total of 2,150 individuals of Mesembrinellinae were collected, representing ten species. Laneela nigripes Guimarães, 1977 was the most abundant species, followed by Mesembrinella bellardiana Aldrich, 1922, Eumesembrinella cyaneicincta (Surcouf, 1919) and Mesembrinella semihyalina Mello, 1967. These species were common and constant during the study period. Mesembrinella batesi Aldrich, 1922, Eumesembrinella quadrilineata (Fabricius, 1805) and Huascaromusca aeneiventris (Wiedmann, 1830) were the less abundant flies, being considered rare and accidental. Eumesembrinella besnoiti (Seguy, 1925) was rare and accessory. Eumesembrinella cyaneicincta, M. bellardiana, M. semihyalina and M. bicolor were mostly collected in site B, while L. nigripes was mostly collected in site C. The edge effect was not evident since the four sites showed similar populations. Site B showed a strong positive relationship between abundance and richness, in site C the correlation was positive and weak, and there was no correlation in A and D. The highest abundance of specimens was recorded during autumn and winter. These flies occurred from the edge up to 2,000m inside the forest.

Resumo Nesse estudo, descrevemos a diversidade de Mesembrinelinae, em uma reserva biológica na cidade de Nova Iguaçu, Estado do Rio de Janeiro. Armadilhas contendo sardinha foram distribuídas sazonalmente em quatro pontos: Ponto A (22° 58.788’ S, 43° 43.459’ W), na borda da mata B (22° 58.523’ S, 43° 44.540’ W), C (22° 58.350’ S, 43° 44.678’ W), e D (22° 34.865’ S, 43º 27.063’ W), localizados a 1.000m, 500m e 2.000m para o interior da borda respectivamente. Foram coletados 2.159 exemplares de Mesembrinellinae, com um total de dez espécies. Laneela nigripes Guimarães, 1977 foi a espécie mais abundante, seguida por Mesembrinella bellardiana Aldrich, 1922, Eumesembrinella cyaneicincta (Surcouf, 1919) e Mesembrinella semihyalina Mello, 1967. Essas espécies foram consideradas comuns e contantes durante o período de estudo. Mesembrinella batesi Aldrich, 1922, Eumesembrinella quadrilineata Fabricius, 1805 e Huascaromusca aeneiventris (Wiedmann, 1830) foram as moscas com as menores abundâncias, sendo consideradas raras e acidentais, Eumesembrinella besnoiti (Seguy, 1925) foi rara e acessória. Eumesembrinella cyaneicincta, M. bellardiana, M. semihyalina e M. bicolor foram as mais coletadas no ponto B, enquanto L. nigripes foi a mais coletada no ponto C. Os efeitos de borda não foram evidentes porque os quatro pontos apresentaram populações similares. O ponto B apresentou uma relação forte e positiva entre a abundância e a riqueza, no ponto C a correlação foi positiva e fraca e não houve correlação nos pontos A e D. A maior abundância de indivíduos foi registrada nas estações do outono e inverno. Espécimes da subfamília Mesembrinellinae ocorreram da borda até 2.000 metros para o interior da mata.

Mesembrinellinae (Diptera: Calliphoridae) to edge effects in the Tinguá Biological Reserve, Rio de Janeiro, Brazil

Abstract In this study we describe the diversity of Mesembrinelinae in a biological reserve in the city of Nova Iguaçu, State of Rio de Janeiro. Traps containing sardines were distributed seasonally, at four sites: Site A (22° 58.788 S, 43° 43.459 W), in a forest edge, and sites B (22° 58.523 S, 43° 44.540 W), C (22° 58.350 S, 43° 44.678 W), and D (22° 34.865 S, 43° 27.063 W), located 1,000m, 500m, and 2,000m respectively, inwards from the edge. A total of 2,150 individuals of Mesembrinellinae were collected, representing ten species. Laneela nigripes Guimarães, 1977 was the most abundant species, followed by Mesembrinella bellardiana Aldrich, 1922, Eumesembrinella cyaneicincta (Surcouf, 1919) and Mesembrinella semihyalina Mello, 1967. These species were common and constant during the study period. Mesembrinella batesi Aldrich, 1922, Eumesembrinella quadrilineata (Fabricius, 1805) and Huascaromusca aeneiventris (Wiedmann, 1830) were the less abundant flies, being considered rare and accidental. Eumesembrinella besnoiti (Seguy, 1925) was rare and accessory. Eumesembrinella cyaneicincta, M. bellardiana, M. semihyalina and M. bicolor were mostly collected in site B, while L. nigripes was mostly collected in site C. The edge effect was not evident since the four sites showed similar populations. Site B showed a strong positive relationship between abundance and richness, in site C the correlation was positive and weak, and there was no correlation in A and D. The highest abundance of specimens was recorded during autumn and winter. These flies occurred from the edge up to 2,000m inside the forest.

Resumo Nesse estudo, descrevemos a diversidade de Mesembrinelinae, em uma reserva biológica na cidade de Nova Iguaçu, Estado do Rio de Janeiro. Armadilhas contendo sardinha foram distribuídas sazonalmente em quatro pontos: Ponto A (22° 58.788 S, 43° 43.459 W), na borda da mata B (22° 58.523 S, 43° 44.540 W), C (22° 58.350 S, 43° 44.678 W), e D (22° 34.865 S, 43º 27.063 W), localizados a 1.000m, 500m e 2.000m para o interior da borda respectivamente. Foram coletados 2.159 exemplares de Mesembrinellinae, com um total de dez espécies. Laneela nigripes Guimarães, 1977 foi a espécie mais abundante, seguida por Mesembrinella bellardiana Aldrich, 1922, Eumesembrinella cyaneicincta (Surcouf, 1919) e Mesembrinella semihyalina Mello, 1967. Essas espécies foram consideradas comuns e contantes durante o período de estudo. Mesembrinella batesi Aldrich, 1922, Eumesembrinella quadrilineata Fabricius, 1805 e Huascaromusca aeneiventris (Wiedmann, 1830) foram as moscas com as menores abundâncias, sendo consideradas raras e acidentais, Eumesembrinella besnoiti (Seguy, 1925) foi rara e acessória. Eumesembrinella cyaneicincta, M. bellardiana, M. semihyalina e M. bicolor foram as mais coletadas no ponto B, enquanto L. nigripes foi a mais coletada no ponto C. Os efeitos de borda não foram evidentes porque os quatro pontos apresentaram populações similares. O ponto B apresentou uma relação forte e positiva entre a abundância e a riqueza, no ponto C a correlação foi positiva e fraca e não houve correlação nos pontos A e D. A maior abundância de indivíduos foi registrada nas estações do outono e inverno. Espécimes da subfamília Mesembrinellinae ocorreram da borda até 2.000 metros para o interior da mata.

A critical period for omega-3 nutritional supplementation in the development of the rodent visual system.

Retinocollicular connections form precise topographical maps that are normally completed through the selective elimination of misplaced axons and the stabilization of topographically ordered axon terminals during early development. Omega-3 fatty acids, acquired exclusively through the diet, and its main metabolite, docosahexaenoic acid (DHA), are involved in brain development and synaptic maturation. We have previously shown that the nutritional restriction of omega-3/DHA results in abnormal retinocollicular topographical fine-tuning. Therefore, we studied the role of omega-3 fatty acids nutritional supplementation and the developmental time windows during which this postnatal supplementation would restore normal topographical maps in the visual system. Female rats and their litters were chronically fed with either control (soy oil) or restricted omega-3 (coconut oil) diets. Fish oil supplementation was introduced between either postnatal day (PND) 7-13, PND7-28 or PND21-42. At PND13, PND28 or PND42, animals received an anterograde eye injection of a neuronal tracer to visualize retinocollicular axons. Confirming previous observations we found that an omega-3/DHA deficiency resulted in an abnormally high innervation density of retinal axons at the visual layers of the superior colliculus (SC). Although a short-term fish oil supplementation between PND7-13 could not restore normal retinocollicular topography, an extended treatment between PND7-28 completely recovered normal innervation densities of retinotectal axons. However, a late onset supplementation protocol, between PND28-42, was no longer effective in the restoration of the abnormal topographical pattern induced by an early omega-3 nutritional malnutrition. The results suggest a critical period for omega3/DHA dietary intake for the proper development of visual topographical maps.

Changes in a nanoparticle's spectroscopic signal mediated by the local environment.

Using a first-principles theoretical model the adsorption of a methyl radical on different sized silver nanoparticles is compared to the adsorption of the same radical on model surfaces. Calculations of our structural, dynamical and electronic properties indicated that small changes in the local environment will lead to small changes in infrared (IR) wavenumbers, but in dramatic changes in the IR signal. Our calculations indicate the lower the adsorption site coordination, the higher is the signal strength, suggesting that small changes in the electronic charge distribution will result in bigger changes in the polarizability and hence in the spectroscopic signal intensity. This effect explains, among others, the signal magnification observed for nanoparticles in surface enhanced Raman spectroscopic (SERS) experiments.

Epidemiological study of myiases in the Hospital do Andaraí, Rio de Janeiro, including reference to an exotic etiological agent.

Myiases are infestations with dipteran larvae in both necrosed and living tissues, the food source of these insects. These illnesses occur in warm humid climates, and are most frequent in developing countries. We assessed the epidemiological aspects and the influence of climate on the occurrence of myiases and the bioagents in patients admitted to the federal Hospital do Andaraí in Rio de Janeiro from February 2007 to 2008. The influence of abiotic factors (temperature, humidity, and rainfall) on the incidence of myiases was investigated by using the Pearson's correlation test. Of the 40 patients studied, the prevalence of myiases was higher in adults, particularly in the 40 to 65 year-old (37.5%) African descent males (57.5%). Most of the injuries were caused by trauma (62.5%). Some patients made use of licit (50%) and illicit drugs (17.2%). The occurrence of myiases was not affected by the abiotic factors investigated. The cases reported here were treated in only one hospital, indicating that the disease is relatively common. The most frequent bioagent was Cochliomyia hominivorax (Coquerel), but Cochliomyia macellaria (Fabricius), Chrysomya albiceps (Wiedemann) and Dermatobia hominis (Wiedemann) (Diptera: Calliphoridae) were also detected causing myiases. Chrysomya albiceps is an exotic etiologic agent of myiases.

Size effects on silver nanoparticles' properties.

In this work a systematic study of the dependence of the structural, electronic, and vibrational properties on nanoparticle size is performed. Based on our total energy calculations we identified three characteristic regimes associated with the nanoparticle's dimensions: (i) below 1.5 nm (100 atoms) where remarkable molecular aspects are observed; (ii) between 1.5 and 2.0 nm (100 and 300 atoms) where the molecular behavior is influenced by the inner core crystal properties; and (iii) above 2.0 nm (more than 300 atoms) where the crystal properties are preponderant. In all considered regimes the nanoparticle's surface modulates its properties. This modulation decreases with the increasing of the nanoparticle's size.

Semiconductor nanoparticle modeling via density functional theory.

In this work, a 2.0 nm nanoparticle (low limit synthesized system) is compared to possible simplified models: passivated clusters, small (1.3 nm) nanoparticles and sets of plane surfaces. Our density functional theory results suggest that even when geometric aspects are properly described by the simplifications considered, electronic properties might be very different, especially when edge atoms are not properly taken into account in the nanoparticle's modeling. In addition, we propose a protocol that might help future theoretical descriptions of nanoparticles.

First record of human myiasis caused by association of the species Chrysomya megacephala (Diptera: Calliplioridae), Sarcophaga (Liopygia) ruficornis (Diptera: Sarcophagidae), and Musca domestica (Diptera: Muscidae).

We report a rare case of myiasis caused simultaneously by three dipterous species. A 54 yr-old indigent patient was admitted to Andaraí Hospital with painful eruptions on the scalp. The parieto-occipital sulcus showed two lesions caused by scratching associated with deep, odoriferous and exudative pediculosis. Larvae removed with the help of forceps and vaseline produced 153 adults, identified in the laboratory as 114 specimens of Chrysomya megacephala (F., 1794), 38 of Sarcophaga (Liopygia) ruficornis (F., 1794), and one of Musca domestica (L., 1758).

Effects of forest fragmentation on dipterofauna (Calliphoridae) at the Reserva Biológica do Tinguá, Nova Iguaçu, RJ.

Samples were collected every month in three different sites of the Reserva Biológica do Tinguá, Brazil: site A was located on the border of the forest and sites B and C were located 1,000 and 500 m, respectively, towards the forest interior. The objective was to determine edge effects on a fragment of the Atlantic Forest. The greatest species richness was observed in sites A and B (23 species), compared with site C (16 species). Site A showed the greatest abundance and constancy, independent of the degree of synanthropy. Asynanthropic species were more abundant and constant in sites B and C. Site B showed the greatest diversity; and sites A and B showed the greatest similarity of populations. There was no significant correlation between Calliphoridae richness and canopy openness except in site C. Richness and abundance were positively correlated with subwood density, except for richness in site B.

Lesion of the subthalamic nucleus reverses motor deficits but not death of nigrostriatal dopaminergic neurons in a rat 6-hydroxydopamine-lesion model of Parkinson's disease

The objective of the present study was to determine whether lesion of the subthalamic nucleus (STN) promoted by N-methyl-D-aspartate (NMDA) would rescue nigrostriatal dopaminergic neurons after unilateral 6-hydroxydopamine (6-OHDA) injection into the medial forebrain bundle (MFB). Initially, 16 mg 6-OHDA (6-OHDA group) or vehicle (artificial cerebrospinal fluid - aCSF; Sham group) was infused into the right MFB of adult male Wistar rats. Fifteen days after surgery, the 6-OHDA and SHAM groups were randomly subdivided and received ipsilateral injection of either 60 mM NMDA or aCSF in the right STN. Additionally, a control group was not submitted to stereotaxic surgery. Five groups of rats were studied: 6-OHDA/NMDA, 6-OHDA/Sham, Sham/NMDA, Sham/Sham, and Control. Fourteen days after injection of 6-OHDA, rats were submitted to the rotational test induced by apomorphine (0.1 mg/kg, ip) and to the open-field test. The same tests were performed again 14 days after NMDA-induced lesion of the STN. The STN lesion reduced the contralateral turns induced by apomorphine and blocked the progression of motor impairment in the open-field test in 6-OHDA-treated rats. However, lesion of the STN did not prevent the reduction of striatal concentrations of dopamine and metabolites or the number of nigrostriatal dopaminergic neurons after 6-OHDA lesion. Therefore, STN lesion is able to reverse motor deficits after severe 6-OHDA-induced lesion of the nigrostriatal pathway, but does not protect or rescue dopaminergic neurons in the substantia nigra pars compacta.

Lesion of the subthalamic nucleus reverses motor deficits but not death of nigrostriatal dopaminergic neurons in a rat 6-hydroxydopamine-lesion model of Parkinson's disease.

The objective of the present study was to determine whether lesion of the subthalamic nucleus (STN) promoted by N-methyl-D-aspartate (NMDA) would rescue nigrostriatal dopaminergic neurons after unilateral 6-hydroxydopamine (6-OHDA) injection into the medial forebrain bundle (MFB). Initially, 16 mg 6-OHDA (6-OHDA group) or vehicle (artificial cerebrospinal fluid - aCSF; Sham group) was infused into the right MFB of adult male Wistar rats. Fifteen days after surgery, the 6-OHDA and SHAM groups were randomly subdivided and received ipsilateral injection of either 60 mM NMDA or aCSF in the right STN. Additionally, a control group was not submitted to stereotaxic surgery. Five groups of rats were studied: 6-OHDA/NMDA, 6-OHDA/Sham, Sham/NMDA, Sham/Sham, and Control. Fourteen days after injection of 6-OHDA, rats were submitted to the rotational test induced by apomorphine (0.1 mg/kg, ip) and to the open-field test. The same tests were performed again 14 days after NMDA-induced lesion of the STN. The STN lesion reduced the contralateral turns induced by apomorphine and blocked the progression of motor impairment in the open-field test in 6-OHDA-treated rats. However, lesion of the STN did not prevent the reduction of striatal concentrations of dopamine and metabolites or the number of nigrostriatal dopaminergic neurons after 6-OHDA lesion. Therefore, STN lesion is able to reverse motor deficits after severe 6-OHDA-induced lesion of the nigrostriatal pathway, but does not protect or rescue dopaminergic neurons in the substantia nigra pars compacta.

Furan interaction with the Si(001)-(2 × 2) surface: structural, energetics, and vibrational spectra from first-principles.

In this work we employ the state of the art pseudopotential method, within a generalized gradient approximation to the density functional theory, to investigate the adsorption process of furan on the silicon (001) surface. A direct comparison of different adsorption structures with x-ray photoelectron spectroscopy (XPS), ultra-violet photoelectron spectroscopy (UPS), high resolution electron energy loss spectroscopy (HREELS), near edge x-ray absorption fine structure (NEXAFS), and high resolution spectroscopy experimental data allows us to identify the [4+2 ] cycloaddition reaction as the most probable adsorbate. In addition, theoretical scanning tunnelling microscopy (STM) images are presented, with a view to contributing to further experimental investigations.

Maleic anhydride adsorption on silicon (001).

The adsorption of maleic anhydride on the Si(001) surface has been investigated using the first-principles pseudopotential formalism. Our total-energy calculations suggest that maleic anhydride (C2H2-C2O3) adsorbs preferentially through a [2+2] cycloaddition of the C=C bond ([2+2]) with an adsorption energy of around 42 kcal/mol. Besides the [2+2] configuration we have also considered other possible coverages and adsorption models, including the adsorption on inter-row and intrarow dimer sites. Based on the analysis of the relative stability of different adsorption models, we propose the formation of mixed domains, containing the [2+2] unit and an interdimer unit. The comparison of our calculated electronic band structure, vibrational modes, and scanning tunneling microscopy images for the [2+2] and the favored interdimer adsorbed structures corroborate our proposed mixed domain model.

Effects of fish oil on the central nervous system: a new potential antidepressant?

In the last 100 years major depression has increased worldwide. In this study we provided coconut fat (CF, rich in saturated fatty acids) or fish oil (FO, rich in n-3 polyunsaturated fatty acids) to female rats throughout pregnancy and lactation and then to their offspring post-weaning and examined lipid brain profile and the possible effect of FO as antidepressant agent in the offspring in adulthood (F1). Rats were submitted to forced swimming test, elevated plus maze, Morris water maze and open field. Peroxidation rate in the cerebral cortex and hippocampus were measured. Docosahexaenoic acid (DHA) concentration in dam's milk, eicosapentaenoic acid (EPA) and DHA concentration in hippocampus and cerebral cortex from F1 rats FO supplemented increased significantly when compared to control (C) and CF rats. Arachidonic acid/EPA ratio in the cerebral cortex and hippocampus decreased in rats submitted to forced swimming test. Peroxidation rate were not different between the groups. Immobility time in the forced swimming test in FO group was reduced (p < 0.01) when compared to C and CF rats. We conclude that lifelong intake of FO was able to induce an antidepressant effect with EPA and DHA concentration increased in the cerebral cortex and hippocampus.

[Cerebral vasculitis and Basedow-Graves disease: report of two cases]. / Vasculite cerebral e doença de Basedow-Graves: relato de dois casos.

OBJECTIVE: To report two cases of patients with cerebral vasculitis and Basedow-Graves disease. CASE REPORT: Two young female patients presented at emergency with acute neurological picture of hemiparesis and speech distress. The first patient, 22 year-old, has been on clinical treatment for hyperthyroidism for one month. On clinical examination she had an elevated cardiac rate, bilateral exophthalmia and a diffuse goiter. On neurological examination we could observe a mild dysarthria and left hemiparesis. The second patient was a 15 year-old girl, who presented sudden conscious loss, aphasia and right hemiparesis. RESULTS: CT scan and MRI showed areas of cerebral infarcts. Angiographic study showed multiple vascular stenosis similar to an arteritic angiographic pattern. Extensive medical and laboratorial workout disclosed no other risk factor for stroke or for nervous system vasculitis. The antimicrosomal and antithyreoglobulin antibodies were positive and thyroidian hormones confirmed hyperthyroidism. CONCLUSION: The concurrence of cerebral arteritis and Basedow-Graves' disease suggest a possible pathogenic link between Graves' disease and specific cerebral vascular disorders, possibly through a common autoimmune mechanism.

[Cerebrovascular disease and neurocysticercosis]. / Doença cerebrovascular e neurocisticercose.

We report three cases of stroke secondary to neurocysticercosis. The first one is a 36 years old man with bilateral middle cerebral artery occlusions who had presented acute right hemiparesia and aphasia. MRI demonstrated several enhancing subarachnoid cysts surrounding the occluded vessels, a right parietal racemose cyst and a left temporal large infarction area. Angiographic study showed total occlusion of left middle cerebral artery and a subtotal occlusion of right middle cerebral artery. The second one is a 42 years old man with vasculitis of small cortical vessels who presented with headache, seizures and focal neurological deficit. CT scan demonstrated several calcifications and a left temporal infarction area. Cerebral angiographic study was normal. The third case was a woman, 53 years old, with a past history of six stroke events and an actual behavior disturbance and seizures. MRI demonstrated several cortical and subcortical infarction areas and cisternal cysts. Angiographic study showed diffuse arteritis of basilar and carotid arterial system. In all three cases CSF study showed linfomonocitic pleocytosis and positive ELISA for cysticercosis.

Ricinine-elicited seizures. A novel chemical model of convulsive seizures.

The present investigation introduces ricinine-elicited seizures as a novel chemical model of convulsive seizure. Ricinine, a neutral alkaloid obtained from the plant Ricinus communis, induces seizures when administered to mice at doses higher than 20 mg/kg. Animals presenting seizures showed a marked preconvulsive phase followed by short duration hind limb myoclonus, respiratory spasms, and death. The lethal nature of ricinine seizures is also pointed out as a good model to study the events causing death in clonic seizures, particularly those related to respiratory spasms, which are also observed in some types of human epilepsy. The behavioral signs of ricinine-elicited seizures are accompanied by electrographic alterations more evident during the preconvulsive phase in the cerebral cortex and more intense during the ictal phase both in the cortex and in the hippocampus. The ricinine-elicited seizures may be inhibited by diazepam but not by phenobarbital, phenytoin, or ethosuximide. Micromolar concentrations of ricinine cause a small decrease in the binding of [3H]-flunitrazepam to cerebral cortex membranes, but do not alter the binding of other radioligands to AMPA, 5-HT(1A), muscarinic, and alpha(1)-adrenergic receptors. Although ricinine presents a cyanide radical, only higher doses of ricinine (4 mM) caused a small impairment of mitochondrial respiration. These results suggest that the mechanism of action of ricinine probably involves the benzodiazepine site in the GABA(A) receptor. This may represent a new mechanism of drug-elicited seizures that may contribute to a better understanding of epilepsy and to new therapeutic approaches to this disease.

Pharmacological evaluation of ricinine, a central nervous system stimulant isolated from Ricinus communis.

The extract of the pericarp of castor bean (Ricinus communis) showed some typical central nervous system stimulant effects when administered to mice. The animals became exophthalmic, presented tremors and clonic seizures and died a few minutes after receiving larger doses of the extract. At lower doses the extract improved memory consolidation and showed some neuroleptic-like properties, such as a decrease in exploratory behavior and catalepsy. The memory-improving effect and the seizure-eliciting properties of the extract were also observed with the administration of ricinine, a neutral alkaloid isolated from the extract. However, the neuroleptic-like properties of the extract were not observed with ricinine. As the therapeutic index of ricinine is of the order of 200, the compound may be considered as a promising cognition-enhancing drug that may be used for the treatment of human amnesias.