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Nanotechnologies are emerging platforms that could be useful in measuring, understanding, and manipulating stem cells. Examples include magnetic nanoparticles and quantum dots for stem cell labeling and in vivo tracking; nanoparticles, carbon nanotubes, and polyplexes for the intracellular delivery of genes/oligonucleotides and protein/peptides; and engineered nanometer-scale scaffolds for stem cell differentiation and transplantation. This review examines the use of nanotechnologies for stem cell tracking, differentiation, and transplantation. We further discuss their utility and the potential concerns regarding their cytotoxicity.

Extramedullary hematopoiesis is a common accompaniment of a variety of hematologic diseases such as hereditary spherocytosis, thalassemia and myelofibrosis. The association of extramedullary hematopoiesis with polycythemia vera in the proliferative phase is much less usual. We report a patient who presented with paraplegia due to spinal cord compression; clinical investigation revealed a paravertebral hematopoietic tumor, and the diagnosis of polycythemia vera was then established.

In a population-based study, all infant deaths occurring in a one-year period in the metropolitan areas of Porto Alegre and Pelotas, in southern Brazil, were studied. There were 227 infants who presented diarrhoea during the fatal illness, and in 75% of these diarrhoea was considered to be the underlying cause of death. Acute diarrhoea (< 14 days' duration) accounted for 28% of the deaths, persistent diarrhoea for 62% and dysentery for a further 10%. Approximately one-half of the children with persistent diarrhoea were admitted to a hospital in the first two weeks of the episode. Hospital-acquired infections were likely to have contributed to one- to two-thirds of deaths due to dysentery and persistent diarrhoea. A comparison with neighbourhood controls showed that breast milk provided substantial protection against deaths due to either acute or persistent diarrhoea.

Population ageing in Brazil has been more rapid and more intense among women. This phenomenon is well described in developed countries where mortality rates are higher for men than women. In this regard, the analysis of mortality patterns by cause contributes to elucidate the determinant factors of the present situation in Brazil and provides indications of some future trends in female mortality. This is especially important due to the fact that in Brazil the social role of women has experienced great changes. This study presents data on mortality from ten capital cities in 1985, showing age-standardized overall and cause-specific mortality rates for five of the main groups of causes by sex. Ratios and differences effect estimators were used. The results revealed that regional patterns are associated with the urban and industrial processes with greater differences by sex in more developed regions. External causes and cardiovascular diseases are the main factors responsible for higher mortality among men with special emphasis on violent deaths. It is inferred that the present trend will be maintained, though it is possible that mortality differences by sex could decrease in the near future. The authors discuss that longer survival among women in Brazil does not reveal better life conditions.

In a population-based case-control study of infant mortality in two urban areas of southern Brazil, the type of milk in an infant's diet was found to be an important risk factor for deaths from diarrhoeal and respiratory infections. Compared with infants who were breast-fed with no milk supplements, and after adjusting for confounding variables, those completely weaned had 14.2 and 3.6 times the risk of death from diarrhoea and respiratory infections, respectively. Part-weaning was associated with corresponding relative risks (RR) of 4.2 and 1.6. The risk of death from infections other than diarrhoea or respiratory infection was less clearly associated with breast-feeding (completely weaned, RR = 2.5; partly weaned, RR = 0.4). Cow's and formula milk seemed to be equally hazardous. For deaths due to diarrhoea the increased risk associated with not breast-feeding was greatest in the first two months of life (RR for completely weaned vs breast-fed without supplementary milk = 23.3).

The validity of the official information on the cause of infant deaths was studied in the Brazilian cities of Porto Alegre and Pelotas in 1985. Using data collected for a population-based case-control study of infant mortality due to infectious diseases or malnutrition, a comparison was made between the causes of death reported on the death certificates and those obtained after a careful review of case-notes and a medical interview with the parents of the decreased infants. Official death certificates showed an excess of deaths attribute to bronchopneumonia (ICD 485X) and septicemia (ICD 038.9), and an underestimation of the number of deaths due to diarrheal diseases (ICD 009.1) and of sudden infant deaths (ICD 798.0). The overall rate of agreement between official and revised certificates, in terms of groups of causes of death, was only 27.9%. Lower respiratory infections, which were the leading infectious cause of infant death according to official statistics, were superseded by diarrheal diseases after this revision.