3 resultados para Rate-limiting steps
Resumo:
Portuguese health care system was created in 1979. It is universal and for free. Expenses are supported by the State through taxes. The modern perinatal care system started by the end of 1970. The first neonatal intensive care units were created in 1980, the Portuguese Neonatal Society in 1985 and the National Neonatal Transport System in 1987. Until the seventies of twentieth century and even during eighties there were more than 200 hospitals with deliveries, a great part without obstetrician or paediatrician, a great percentage of pregnancies had no prenatal care, there were few neonatal intensive care units and perinatal mortality rate was one of the highest in the European countries. In 1987 an Experts Committee was nominated by the Health Ministry aiming to collect and analyse data on perinatal care and to suggest improvements. The Report resulting from this work is the main document on which is based the reform. The reform was a 9 years program in 3 years stages aiming to close hospitals with less than 1500 deliveries/year, to reclassify hospitals, to create Coordinating Units between health centres and hospitals, to equip neonatal intensive and intermediate care units, to define needs of obstetricians, paediatricians and nurses for each centre and to promote specialised training in neonatology for paediatricians and nurses. Levels of perinatal care were defined as well as localization of each level of hospital according to the number of deliveries in one geographic area, geographic difficulties and existing routes and connections. Steps for opening and closure of different levels of hospitals were very well programmed. The organization, capacities, number of obstetricians, neonatologists and nurses as well as equipment for each level of care was defined. Rules for pregnant women and newborns transfer from level II to level III hospitals were also well described. A specific training is neonatology was created starting in 1990. This organization resulted in an impressive decrease in mortality rates at all levels and still it is the policy we have today.
Resumo:
BACKGROUND: This study was designed to investigate, for the first time, the short-term molecular evolution of the HIV-2 C2, V3 and C3 envelope regions and its association with the immune response. Clonal sequences of the env C2V3C3 region were obtained from a cohort of eighteen HIV-2 chronically infected patients followed prospectively during 2-4 years. Genetic diversity, divergence, positive selection and glycosylation in the C2V3C3 region were analysed as a function of the number of CD4+ T cells and the anti-C2V3C3 IgG and IgA antibody reactivity RESULTS: The mean intra-host nucleotide diversity was 2.1% (SD, 1.1%), increasing along the course of infection in most patients. Diversity at the amino acid level was significantly lower for the V3 region and higher for the C2 region. The average divergence rate was 0.014 substitutions/site/year, which is similar to that reported in chronic HIV-1 infection. The number and position of positively selected sites was highly variable, except for codons 267 and 270 in C2 that were under strong and persistent positive selection in most patients. N-glycosylation sites located in C2 and V3 were conserved in all patients along the course of infection. Intra-host variation of C2V3C3-specific IgG response over time was inversely associated with the variation in nucleotide and amino acid diversity of the C2V3C3 region. Variation of the C2V3C3-specific IgA response was inversely associated with variation in the number of N-glycosylation sites. CONCLUSION: The evolutionary dynamics of HIV-2 envelope during chronic aviremic infection is similar to HIV-1 implying that the virus should be actively replicating in cellular compartments. Convergent evolution of N-glycosylation in C2 and V3, and the limited diversification of V3, indicates that there are important functional constraints to the potential diversity of the HIV-2 envelope. C2V3C3-specific IgG antibodies are effective at reducing viral population size limiting the number of virus escape mutants. The C3 region seems to be a target for IgA antibodies and increasing N-linked glycosylation may prevent HIV-2 envelope recognition by these antibodies. Our results provide new insights into the biology of HIV-2 and its relation with the human host and may have important implications for vaccine design.