Health implications of engineered nanoparticles in infants and children.

BACKGROUND: The nanotechnology boom and the ability to manufacture novel nanomaterials have led to increased production and use of engineered nanoparticles (ENPs). However, the increased use of various ENPs inevitably results in their release in or the contamination of the environment, which poses significant threats to human health. In recent years, extraordinary economic and societal benefits of nanoproducts as well as their potential risks have been observed and widely debated. To estimate whether ENPs are safe from the onset of their manufacturing to their disposal, evaluation of the toxicological effects of ENPs on human exposure, especially on more sensitive and vulnerable sectors of the population (infants and children) is essential. DATA SOURCES: Papers were obtained from PubMed, Web of Science, and Google Scholar. Literature search words included: "nanoparticles", "infants", "children", "exposure", "toxicity", and all relevant cross-references. RESULTS: A brief overview was conducted to 1) characterize potential exposure routes of ENPs for infants and children; 2) describe the vulnerability and particular needs of infants and children about ENPs exposure; 3) investigate the current knowledge about the potential health hazards of ENPs; and 4) provide suggestions for future research and regulations in ENP applications. CONCLUSIONS: As the manufacturing and use of ENPs become more widespread, directed and focused studies are necessary to measure actual exposure levels and to determine adverse health consequences in infants and children.

[Development of a protocol on pulsed field gel electrophoresis analysis for Streptococcus suis].

OBJECTIVE: To develop a PFGE protocol for Streptococcus suis. METHODS: We developed and optimized a PFGE protocol for S. suis, in terms of plug preparation, choice of restriction endonucleases and optimized electrophoresis parameters. By analyzing the genome sequences of S. suis P1/7 with Mapdraw of DNAStar, we found three restriction enzymes, Swa I, Sma I and Apa I, were more suitable than others. RESULTS: Analysis of 100 isolates of S. suis including 34 of 35 serotypes identified, 59, 53 and 43 patterns were obtained from Swa I, Sma I and Apa I restriction, respectively. The enzyme Swa I had the greatest power for discrimination ability. CONCLUSION: By optimization of the protocol at various conditions, a rapid, reproducible, economic and practical PFGE method for S. suis was developed.

[An outbreak of human Streptococcus suis serotype 2 infections presenting with toxic shock syndrome in Sichuan, China].

OBJECTIVE: In mid-July 2005, five patients presented with septic shock to a hospital in Ziyang city in Sichuan, China, to identify the etiology of the unknown reason disease, an epidemiological, clinical, and laboratory study were conducted. METHODS: An enhanced surveillance program were established in Sichuan, the following activities were introduced: active case finding in Sichuan of (a) laboratory diagnosed Streptococcus suis infection and (b) clinically diagnosed probable cases with exposure history; supplemented by (c) monitoring reports on meningococcal meningitis. Streptococcus suis serotype 2 infection was confirmed by culture and biochemical reactions, followed by sequencing for specific genes for serotype and virulence factors. RESULTS: From June 10 to August 21, 2005, 68 laboratory confirmed cases of human Streptococcus suis infections were reported. All were villagers who gave a history of direct exposure to deceased or sick pigs in their backyards where slaughtering was performed. Twenty six (38%) presented with toxic shock syndrome of which 15 (58%) died. Other presentations were septicaemia or meningitis. All isolates were tested positive for genes for tuf, species-specific 16S rRNA, cps2J, mrp, ef and sly. There were 136 clinically diagnosed probable cases with similar exposure history but incomplete laboratory investigations. CONCLUSION: An outbreak of human Streptococcus suis serotype 2 infections occurred in villagers after direct exposure to deceased or sick pigs in Sichuan. Prohibition of slaughtering in backyards brought the outbreak to a halt. A virulent strain of the bacteria is speculated to be in circulation, and is responsible for the unusual presentation of toxic shock syndrome with high case fatality.