Methane emission suppression in flooded soil from Amazonia

The coupling between ferrous iron and methane production has important global implications, with iron ions acting as electron acceptors for anaerobic oxidation of methane (AOM) and inhibitors of methanogenesis in different environments, including floodplain soils. In this sense, we analyzed the relationship between Fe(II) concentration and methane production in soil layers collected at 0-15 cm and 15-30 cm from flooded-forest and -agroforestry in Amazonian clear water floodplain incubated in anaerobic batch reactors using acetate, formate and glucose as organic sources. High throughput sequencing of archaeal and bacterial 16S rRNA genes was employed to assess the abundance and composition of the active methanogenic and methanotrophic microbial groups potentially involved in Fe(III)-dependent AOM in the soil used as inoculum. Positive correlation was revealed between Fe(II) concentration and methane production, with higher accumulation of Fe(II) in incubated soil layer collected at 0-15 cm in both forest and agroforestry sites for all the three organic sources. The accumulation of Fe(II) in the incubated soil evidenced the oxidation of Fe(III) potentially by Methanobacterium, Desulfobulbus and 'Candidatus methanoperedens nitroreducens' living in anaerobic condition at this soil layer. The results point out to the microbial ferric iron reduction as an important potential pathway for anaerobic organic matter decomposition in Amazonian floodplain, evidencing methanogenesis suppression by Fe(III) reduction in flooded-forest and -agroforestry in Amazonian clear water river floodplain.

[Acute psychotic disorder associated with vigabatrin]

Vigabatrin, a drug mainly used in the treatment of therapy-resistant epilepsy, has been associated to a large range of adverse effects, including acute psychotic disorders. The authors report the case of a 44-year-old patient with drug-resistant temporal lobe epilepsy that developed an acute psychotic episode about three weeks after initiating medication with vigabatrin. After the withdrawal of vigabatrin and the addition of an antipsychotic drug, the clinical picture improved promptly and the patient was discharged within a short period of time. The authors discuss the patient's diagnosis, the possible mechanisms of vigabatrin-associated psychosis and the therapeutic approach, stressing the questions that concern vigabatrin prescription and withdrawal.

Migraine with prolonged aura

We present the case of a 29-year-old man with a long history of migraine with aura, in whom migraine with prolonged aura was induced after the sudden withdrawal of prophylactic therapy.