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Particles can be delivered to the respiratory tract of animals using various techniques. Inhalation mimics environmental exposure but requires large amounts of aerosolized NPs over a prolonged dosing time, varies in deposited dose among individual animals, and results in nasopharyngeal and fur particle deposition. Although less physiological, intratracheal (IT) instillation allows quick and precise dosing. Insufflation delivers particles in their dry form as an aerosol. We compared the distribution of neutron-activated 141CeO2 nanoparticles (5 mg/kg) in rats after 1) IT instillation, 2) left intrabronchial instillation, 3) microspraying of nanoceria suspension, and 4) insufflation of nanoceria dry powder. Blood, tracheobronchial lymph nodes, liver, gastrointestinal tract, feces and urine were collected at 5 minutes and 24 hours post-dosing. Excised lungs from each rat were dried at room temperature while inflated at a constant 30 cm water pressure. Dried lungs were then sliced into 50 pieces. The radioactivity of each lung piece and other organs was measured. The evenness index (El) of each lung piece was calculated [EI=(μCi/mgpiece)/(μCi/mglung)]. The degree of EI value departure from 1.0 is a measure of deposition heterogeneity. We showed that the pulmonary distribution of nanoceria differs among modes of administration. Dosing by IT or microspraying resulted in similar spatial distribution. Insufflation resulted in significant deposition in the trachea and in more heterogeneous lung distribution. Our left intrabronchial instillation technique yielded a concentrated deposition into the left lung. We conclude that animal dosing techniques and devices result in varying patterns of particle deposition that will impact biokinetic and toxicity studies.

RESUMO:A incontinência fecal é um problema de enorme impacto social e econômico. Com semelhante semblante encontrase a colostomia definitiva, outra situação de igual gravidade e impacto sobre a vida dos pacientes. Neste trabalho, reuniram-se artigos retirados das bases de dados Cochrane Library, Medline e Embase para tratar das atuais situações desses problemas. A abordagem é realizada através dos tópicos Prevalência e impacto, Etiologia e Tratamento, sendo nesse último descrito e comentado o procedimento do transplante anorretal. A análise realizada revela a atual situação ruim para o tratamento da incontinência fecal e colostomia definitiva, mas coloca o transplante anorretal como proposta futura capaz de alterar essa realidade. DESCRITORES:Transplante heterotópico; Transplante autólogo; Transplante isogênico; Incontinência fecal; Colostomia.ABSTRACT: Fecal incontinence is a problem of great social and economic impact. With similar aspects, there is the definitive colostomy, another situation of equal gravity and impact over the patient's lives. In this work, articles from Cochrane Library, Medline and Embase were revised using these problems as parameters. The approach is systematically accomplished through the topics Prevalence and impact, Etiology and Treatment, with the description of anorectal transplantation in this last topic. The analysis reveals the bad situation of treatment for fecal incontinence and definitive colostomy nowadays, but settles the anorectal transplantation as a future proposal capable of changing this reality. KEYWORDS:

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