Writing epilepsy: a neurophysiological, neuropsychological and neuroimaging study

Writing epilepsy is a rare reflex syndrome in which seizures are triggered by writing. We describe a 33-year-old, right-handed man, with a history of juvenile absence epilepsy in remission and a family history of epilepsy, in whom myoclonic jerks precipitated exclusively by writing started at the age of 30. Intensive video/EEG monitoring during neuropsychological tests revealed, at about 1 minute after starting to write, a dystonic posture, followed by myoclonic jerks involving the right hand that shortly after became generalized. Concomitantly, the ictal EEG documented generalized hypersynchronous polyspike-wave discharges, maximal over the right parietocentral area. SPECT revealed an ictal hyperperfusion and interictal hypoperfusion over right parietofrontal regions, and fMRI showed extensive and intense left frontal, supplementary motor area activation, induced by writing. This case study provides some evidence supporting the hypothesis that the mechanism underlying writing-triggered seizures may be a generalized seizure process, with a focal cortical trigger zone, presumed to be the left frontal lobe as suggested by clinical and fMRI data. A relevant role played by the right hemisphere (right parietofrontal region) is postulated in the full-blown expression of reflex epileptogenesis, as supported by EEG and SPECT findings.     

Interpopulation variability among Panstrongylus megistus (Hemiptera: Reduviidae) from Brazil

Comparisons were made among Panstrongylus megistus (Burmeister) from three areas of Brazil (Bahia, Minas Gerais, and Santa Catarina), where populations differ with regard to their degree of association with human dwellings. The following characters were studied: morphology of the eggs and the male genitalia; morphometry of the head and thorax; isoenzyme profile; enzymatic activity of the alpha-glycerophosphate dehydrogenase (alpha-GPDH); and cytogenetics. In general, differences were observed in the weight, diameter, and length of the egg among Bahia, Minas Gerais, and Santa Catarina populations. Differences were not observed in the architecture of the egg exochorion. The size of the median process of the pygophore of the male genitalia of individuals from Bahia differed from the other two populations. The Minas Gerais population presented the largest number of denticles in the endosome process. The morphometry of the head and thorax differentiated Santa Catarina from the Bahia and Minas Gerais populations. Phosphoglucomutase (EC 5.4.2.2., PGM) was the only enzyme out of 11 that showed polymorphism; the population from Minas Gerais was most polymorphic, whereas the population from Santa Catarina was monomorphic. Study of the alpha-GPDH activity and cytogenetics did not reveal differences among the three populations. Analysis of all the characters studied together with information on these three populations from previous publications allowed a phenogram to be constructed. Two distinct groups were evident, one represented by Santa Catarina and the other by Bahia and Minas Gerais. Considering the greater variability of the Minas Gerais and Bahia populations, we propose the inclusion of these states within the area of origin of P. megistus.     

Soluble factors released by Toxoplasma gondii-infected astrocytes down-modulate nitric oxide production by gamma interferon-activated microglia and prevent neuronal degeneration

The maintenance of a benign chronic Toxoplasma gondii infection is mainly dependent on the persistent presence of gamma interferon (IFN-gamma) in the central nervous system (CNS). However, IFN-gamma-activated microglia are paradoxically involved in parasitism control and in tissue damage during a broad range of CNS pathologies. In this way, nitric oxide (NO), the main toxic metabolite produced by IFN-gamma-activated microglia, may cause neuronal injury during T. gondii infection. Despite the potential NO toxicity, neurodegeneration is not a common finding during chronic T. gondii infection. In this work, we describe a significant down-modulation of NO production by IFN-gamma-activated microglia in the presence of conditioned medium of T. gondii-infected astrocytes (CMi). The inhibition of NO production was paralleled with recovery of neurite outgrowth when neurons were cocultured with IFN-gamma-activated microglia in the presence of CMi. Moreover, the modulation of NO secretion and the neuroprotective effect were shown to be dependent on prostaglandin E(2) (PGE(2)) production by T. gondii-infected astrocytes and autocrine secretion of interleukin-10 (IL-10) by microglia. These events were partially eliminated when infected astrocytes were treated with aspirin and cocultures were treated with anti-IL-10 neutralizing antibodies and RP-8-Br cyclic AMP (cAMP), a protein kinase A inhibitor. Further, the modulatory effects of CMi were mimicked by the presence of exogenous PGE(2) and by forskolin, an adenylate cyclase activator. Altogether, these data point to a T. gondii-triggered regulatory mechanism involving PGE(2) secretion by astrocytes and cAMP-dependent IL-10 secretion by microglia. This may reduce host tissue inflammation, thus avoiding neuron damage during an established Th1 protective immune response.     

A low carbohydrate diet affects autonomic modulation during heavy but not moderate exercise

The aim of this study was to examine the effects of low carbohydrate (CHO) availability on heart rate variability (HRV) responses during moderate and severe exercise intensities until exhaustion. Six healthy males (age, 26.5 ± 6.7 years; body mass, 78.4 ± 7.7 kg; body fat %, 11.3 ± 4.5%; [(V)\dot] \textO_{2 max} , \dot{V} {\text{O}}_{{2{ \max }}} , 39.5 ± 6.6 mL kg⁻¹ min⁻¹) volunteered for this study. All tests were performed in the morning, after 8–12 h overnight fasting, at a moderate intensity corresponding to 50% of the difference between the first (LT₁) and second (LT₂) lactate breakpoints and at a severe intensity corresponding to 25% of the difference between the maximal power output and LT₂. Forty-eight hours before each experimental session, the subjects performed a 90-min cycling exercise followed by 5-min rest periods and subsequent 1-min cycling bouts at 125% [(V)\dot] \textO_{2 max} \dot{V} {\text{O}}_{{2{ \max }}} (with 1-min rest periods) until exhaustion, in order to deplete muscle glycogen. A diet providing 10% (CHO_low) or 65% (CHO_control) of energy as carbohydrates was consumed for the following 2 days until the experimental test. The Poicaré plots (standard deviations 1 and 2: SD1 and SD2, respectively) and spectral autoregressive model (low frequency LF, and high frequency HF) were applied to obtain HRV parameters. The CHO availability had no effect on the HRV parameters or ventilation during moderate-intensity exercise. However, the SD1 and SD2 parameters were significantly higher in CHO_low than in CHO_control, as taken at exhaustion during the severe-intensity exercise (P < 0.05). The HF and LF frequencies (ms²) were also significantly higher in CHO_low than in CHO_control (P < 0.05). In addition, ventilation measured at the 5 and 10-min was higher in CHO_low (62.5 ± 4.4 and 74.8 ± 6.5 L min⁻¹, respectively, P < 0.05) than in CHO_control (70.0 ± 3.6 and 79.6 ± 5.1 L min⁻¹, respectively; P < 0.05) during the severe-intensity exercise. These results suggest that the CHO availability alters the HRV parameters during severe-, but not moderate-, intensity exercise, and this was associated with an increase in ventilation volume.     

Extract of the bristles of Dirphia sp. increases nitric oxide in a rat pleurisy model

Objectives In the present study we assessed the inflammatory potential of venom obtained from caterpillar genus Dirphia in an acute model of lung injury. Material and methods Injection of extract from the bristles of Dirphia sp. (EBD) into the pleural cavity of rats elicited an acute inflammation response characterized by fluid accumulation which contained a large number of polymorphonuclear neutrophils (PMNs). Results The results show that EBD induces an inflammatory response, with a significant increase in PMNs, exudate and nitric oxide within 4 h after a 0.04 mg/kg dose. The administration of anti-inflammatory drugs (fructose-1,6-bisphosphate, dexamethasone, rofecoxib, sodium diclofenac and pyrilamine) significantly reduced the inflammatory effect of EBD. Conclusions EBD causes an inflammatory reaction in the pleural cavity of rats involving a variety of inflammatory mediators, its action mechanism probably involving cellular injury and the exacerbated induction of cytokines and nitric oxide. Received 23 June 2005; returned for revision 24 August 2005; returned for final revision 2 October 2005; accepted by I. Ahnfelt-R?nne 13 October 2005     

Genetic Structure and Origin of Peopling in The Azores Islands (Portugal): The View from mtDNA

The Azores islands (Portugal), uninhabited when discovered by Portuguese navigators in the fifteenth century, are located in the Atlantic Ocean 1500 km from the European mainland. The archipelago is formed by nine islands of volcanic origin that define three geographical groups: Eastern (S. Miguel and Sta. Maria), Central (Terceira, Faial, Pico, Graciosa and S. Jorge) and Western (Flores and Corvo). To improve the genetic characterisation of the Azorean population, and to clarify some aspects related to the history of settlement, a study of mtDNA was conducted in the population of the archipelago. The HVRI region was sequenced and specific RFLPs were screened in 146 samples obtained from unrelated individuals with Azorean ancestry (50 from the Eastern group, 60 from the Central group, and 37 from the Western group). Samples were classified into haplogroups based on the information obtained from both sequencing and RFLP analysis. All the analyses performed support the idea that, in the whole group of islands, the majority of mtDNA lineages originated from the Iberian Peninsula, mainly from Portugal (mainland). However contributions from other European populations, especially from Northern Europe, cannot be disregarded. The values obtained for the various diversity parameters in the Azores archipelago indicate that the Azorean population, as a whole, does not exhibit the typical characteristics of an isolated population. The analysis of genetic data by groups of islands showed that the Western group exhibited particular features. The distribution of haplogroups in the Western group is very atypical, being significantly different from what is observed in the Eastern and Central groups. Furthermore, the diversity values are, in general, lower than those observed in other populations used for comparison. African haplogroups were found in all the groups of islands. Therefore the presence of Moorish and African slaves on the islands, as reported in historical sources, is supported by the mtDNA genetic data, especially in the Eastern group. The presence of Jews in the Central group is also supported by the mtDNA data. Neither historical nor genetic data (phylogeography of mtDNA) supports the idea of a differential settlement history for the Western group; however, it is represented in the phylogenies as an isolated branch. The effect of genetic drift, induced by the reduced population size since peopling occurred, has led to a very atypical distribution of haplogroups/haplotypes in this group of islands. We cannot ignore the influence of biodemographic and genetic processes, namely founder effect, genetic drift, migration, and even recent mutational events in the mtDNA lineages of the Azorean populations. Nevertheless, a great part of the variation in the Azorean mtDNA can be explained by the settlement history.     

Genetic polymorphism in <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis> I isolated from Brazilian Northeast triatomines revealed by low-stringency single specific primer–polymerase chain reaction

Different molecular markers have been employed for typing Trypanosoma cruzi strains from endemic areas of Chagas disease. The low-stringency single specific primer-polymerase chain reaction (LSSP-PCR) has been a sensitive and informative technique that uses the variable region of kinetoplast DNA minicircles as a genetic marker, allowing detection of DNA sequence variation. In the present study, we analyzed the intra-lineage genetic variability of the T. cruzi strains obtained from triatomine feces collected on filter paper FTA card by LSSP-PCR. The hybridization of the PCR products with a probe for the subgenus Schizotrypanum and a clone-specific probe from Dm28c confirmed the subgenus as T. (S.) cruzi and respective lineages as T. cruzi I. Phenetic analysis showed the presence of three clusters that diverged by different coefficients of similarity. Thirteen T. cruzi I genotypes were observed circulating among Triatoma pseudomaculata and Rhodnius nasutus from peridomiciliary and natural environments in five peri-urban and urban localities of Jaguaruana, Ceará, Brazil. These data indicate the importance of the circulation of T. cruzi I genotypes among T. pseudomaculata and R. nasutus in different environments and the possible risk of Chagas disease domestic transmission.