Mesozoic tectonic inversion in the Neuquen Basin of west-central Argentina

Mesozoic tectonic inversion in the Neuquen Basin of west-central Argentina produced two main fault systems: (1) deep faults that affected basement and syn-rift strata where preexisting faults were selectively reactivated during inversion based on their length and (2) shallow faults that affected post-rift and syn-inversion strata. Normal faults formed at high angle to the reactivated half-graben bounding fault as a result of hangingwall expansion and internal deformation as it accommodated to the shape of the curved footwall during oblique inversion. Contraction during inversion was initially accommodated by folding and internal deformation of syn-rift sedimentary wedges, followed by displacement along half-graben bounding faults. We suspect that late during inversion the weight of the overburden inhibited additional fault displacement and folding became the shortening-accommodating mechanism. A Middle Jurassic inversion event produced synchronous uplift of inversion structures across the central Neuquen Basin. Later inversion events (during Late Jurassic, Early Cretaceous, and Late Cretaceous time) produced an "inversion front" that advanced north of the Huincul Arch. Synchroneity of fault reactivation during the Callovian inversion event may be related to efficient stress transmission north of the Huincul Arch, probably due to easy reactivation of low-dip listric fault segments. This required little strain accumulation along "proximal" inversion structures before shortening was transferred to more distal structures. Later inversion events found harderto- reactivate fault segments, resulting in proximal structures undergoing significant inversion before transferring shortening. The time between the end of rifting and the different inversion events may have affected inversion. Lithosphere was probably thermally weakened at the onset of the initial Callovian inversion phase, allowing stress transmission over a large distance from the Huincul Arch and causing synchronous inversion across the basin. Later inversion affected a colder and more viscous lithosphere. Significant strain needed to accumulate along proximal inversion structures before shortening was transferred to more distal parts of the basin. Timing of inversion events along the central Neuquen Basin suggest a megaregional control by right-lateral displacement motion along the Gastre Fault Zone, an intracontinental megashear zone thought to have been active prior to and during the opening of the South Atlantic Ocean

Leishmania mexicana amazonensis isolated from a patient with fatal mucosal leishmaniasis

Faculdade de Medicina (FMD

Leishmaniose mucosa ("espundia") respondendo a baixa dose de N-metil-glucamina (Glucantime ®) no Rio de Janeiro, Brasil

Response to treatment with antimonial drugs varies considerably depending on the parasite strain involved, immune status of the patient and clinical form of the disease. Therapeutic regimens with this first line drug have been frequently modified both, in dose and duration of therapy. A regimen of 20 mg/kg/day of pentavalent antimony (Sb5+) during four weeks without an upper limit on the daily dose is currently recommended for mucosal disease ("espundia"). Side-effects with this dose are more marked in elderly patients, more commonly affected by this form of leishmaniasis. According to our experience, leishmaniasis in Rio de Janeiro responds well to antimony and, in cutaneous disease, high cure rates are obtained with 5 mg/kg/day of Sb5+ during 30 to 45-days. In this study a high rate of cure (91.4%) employing this dose was achieved in 36 patients with mild disease in this same geographic region. Side-effects were reduced and no antimony refractoriness was noted with subsequent use of larger dose in patients that failed to respond to initial schedule.A resposta de pacientes com leishmaniose ao tratamento antimonial pode variar em função de fatores como a cepa do parasito envolvido, estado imunológico do paciente e a forma clínica da doença. Os esquemas terapêuticos com antimônio pentavalente (Sb5+) têm sido frequentemente modificados quanto à dose e duração da terapia. Os efeitos colaterais observados com o uso de 20 mg/kg/dia de Sb5+ durante quatro semanas (dose recomendada para o tratamento da forma mucosa) são mais acentuados em pacientes idosos, os mais afetados pela forma mucosa (espundia) da doença. Nossa experiência demonstra que a forma cutânea ocorrendo no Rio de Janeiro responde muito bem ao tratamento com a dose de 5 mg/kg/dia de Sb5+ durante 30 ou 45 dias. Neste estudo foi obtida elevada eficácia (91,4%) com o mesmo regime terapêutico em 36 pacientes com espundia (que evoluem, contudo, com lesão crônica menos destrutiva do que o observado em outras áreas endêmicas) procedentes desta região. Os efeitos colaterais foram reduzidos, não havendo também qualquer resistência ao emprego de doses maiores nos casos que não responderam ao tratamento inicial

Minicircle kDNA microheterogeneity in Endotrypanum indicate diversity within this genus.

A comparison of kDNA restriction-endonuclease fragment patterns from strains representing selected Endotrypanum zymodemes was done by schizodeme analysis. As the degree of heterogeneity within mini-circles varied among species or strains of Endotrypanum, the fingerprint obtained with each of the restriction enzymes was unique for each of these parasites. The data have revealed that this trypanosomatid genus is much more complex than it was originally thought to be