Maternal neurofascin-specific autoantibodies bind to structures of the fetal nervous system during pregnancy, but have no long term effect on development in the rat

Neurofascin was recently reported as a target for axopathic autoantibodies in patients with multiple sclerosis (MS), a response that will exacerbate axonal pathology and disease severity in an animal model of multiple sclerosis. As transplacental transfer of maternal autoantibodies can permanently damage the developing nervous system we investigated whether intrauterine exposure to this neurofascin-specific response had any detrimental effect on white matter tract development. To address this question we intravenously injected pregnant rats with either a pathogenic anti-neurofascin monoclonal antibody or an appropriate isotype control on days 15 and 18 of pregnancy, respectively, to mimic the physiological concentration of maternal antibodies in the circulation of the fetus towards the end of pregnancy. Pups were monitored daily with respect to litter size, birth weight, growth and motor development. Histological studies were performed on E20 embryos and pups sacrificed on days 2, 10, 21, 32 and 45 days post partum. Results: Immunohistochemistry for light and confocal microscopy confirmed passively transferred anti-neurofascin antibody had crossed the placenta to bind to distinct structures in the developing cortex and cerebellum. However, this did not result in any significant differences in litter size, birth weight, or general physical development between litters from control mothers or those treated with the neurofascin-specific antibody. Histological analysis also failed to identify any neuronal or white matter tract abnormalities induced by the neurofascin-specific antibody. Conclusions: We show that transplacental transfer of circulating anti-neurofascin antibodies can occur and targets specific structures in the CNS of the developing fetus. However, this did not result in any pre- or post-natal abnormalities in the offspring of the treated mothers. These results assure that even if anti-neurofascin responses are detected in pregnant women with multiple sclerosis these are unlikely to have a negative effect on their children

Margin Rules, Informed Trading in Derivatives and Price Dynamics

We analyze the impact of option trading and margin rules on the behavior of informed traders and on the microstructure of stock and option markets. In the absence of binding margin requirements, the introduction of an options market causes informed traders to exhibit a relative trading bias towards the stock because of its greater information sensitivity. In turn, this widens the stock's bid-ask spread. But when informed traders are subject to margin requirements, their bias towards the stock is enhanced or mitigated depending on the leverage provided by the option relative to the stock, leading to wider or narrower stock bid-ask spreads. The introduction of option trading, with or without margin requirements, unambiguously improves the informational efficiency of stock prices. Margin rules improve market efficiency when stock margins and options margins (relative to stock margins) are sufficiently large or small but not when they are of moderate size.

Aumento na detecção de casos de hanseníase em São Luís, Maranhão, Brasil, de 1993 a 1998: a endemia está em expansão? Increase in leprosy detection rates in São Luís, Maranhão, Brazil, from 1993 to 1998: is the endemic expanding?

Foi realizado estudo epidemiológico descritivo sobre detecção de casos novos de hanseníase em São Luís, Maranhão, Brasil, de 1993 a 1998, a partir da criação de banco de dados com 2.796 notificações. Foram calculados coeficientes de detecção brutos e específicos por sexo, forma clínica e faixa etária. Foi analisada sua tendência temporal por meio dos modelos de ajuste linear, exponencial, geométrico e logarítmico. Evidenciou-se tendência de aumento às custas do sexo feminino e das formas paucibacilares, principalmente da tuberculóide, e mais acentuada na população de 15 a 19 anos. O percentual da detecção em menores de 15 anos indicou necessidade de busca ativa da doença nesta população.<br>A descriptive epidemiologic study on the detection of new leprosy cases was conducted in São Luís, Maranhão, Brazil, from 1993 to 1998. A database was created for the purpose, covering 2,796 reported cases. General detection rates were calculated, as well as specific rates by gender, clinical type, and age group. Linear, exponential, geometric, and log adjustment models were performed to analyze time trends in the disease. An increase in detection was observed, involving mostly female and paucibacillary cases, mainly of tuberculoid leprosy. The increase in detection was most evident in the 15 to 19 year-old population. The percentage of detection under 15 indicated the need for active case search in this group