Biodistribution of Transplanted Hematopoietic Precursor Cells Injected Through Different Administration Routes in Newborn Mice.

Hematopoietic stem cell transplantation has been studied for several decades now, mostly as a treatment for malignancies and hematological diseases but also for genetic metabolic disorders. Since many diseases that could be potentially treated with this approach develop early in life, studies of cell transplantation in newborn mice are needed, especially for gene therapy protocols. However, the small size of pups restricts the possibilities for routes of administration, and those available are normally technically challenging. Our goal was to test different routes of administration of Lin- cells in 2-day-old mice: intraperitoneal, intravenous through temporal vein (TV), and intravenous through retro-orbital (RO) sinus. Routes were evaluated by their easiness of execution and their influence in the biodistribution of cells in the short (48 h) and medium (30 days) term. In either 48 h or 30 days, all three routes presented similar results, with cells going mostly to bone marrow, liver, and spleen in roughly the same number. RO injection resulted in quick distribution of cells to the brain, suggesting better performance than the others. Rate of failure was higher for the TV route, which was also the hardest to execute, whereas the other two were considered easier. In conclusion, TV was the hardest to perform and all routes seemed to demonstrate similar results for cell biodistribution. In particular, the RO injection results in quicker biodistribution of cells to the brain, which is particularly important in the study of genetic metabolic disorders with a neurological component.

Polydimethylsiloxane/nano calcium phosphate composite tracheal stents: Mechanical and physiological properties.

In this study, we report the production and characterization of tracheal stents composed of polydimethylsiloxane/nanostructured calcium phosphate composites obtained by reactive synthesis. Tracheal stents were produced by transfer molding, and in vivo tests were carried out. PDMS was combined with H3 PO4 and Ca(OH)2 via an in situ reaction to obtain nanoparticles of calcium phosphate dispersed within the polymeric matrix. The incorporation of bioactive inorganic substances, such as calcium phosphates, improved biological properties, and the in situ reaction allowed tight coupling of particles to the matrix. Results showed the presence of the nanoparticles of DCPA and CDHA. The porosity generated during mixing decreased the tensile strength and tear properties. Composites presented higher values of cell viability compared with those for PDMS. In vivo tests indicated the presence of inflammatory tissue 30 days after implantation in both cases. Thus, the present biomaterial shows potential for application in tracheal disease, however further evaluation is needed. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 545-553, 2019.

O modelo experimental de carcinogênese gástrica induzido por n-methyl-n-nitrosourea em ratos F344 e camundongos C3H é válido para os ratos Wistar? / Experimental model of gastric carcinogenesis with N-methyl-N-nitrosourea for F344 rats and C3H mices is valid for Wistar rats?

INTRODUÇÃO: O N-metil-N-nitrosourea (MNU) tem ação cancerígena direta, induzindo tumores em várias espécies em uma variedade de órgãos, incluindo o estômago de ratos. Tratamento do MNU na água de beber por 25-42 semanas, seletivamente, induz carcinoma gástrico glandular de ratos F344 e camundongos C3H. OBJETIVO: Estabelecer um modelo experimental para indução seletiva de câncer no estômago glandular de ratos Wistar com MNU. MÉTODOS: Um total de 48 ratos Wistar machos com oito semanas, foram utilizados no presente estudo. MNU (Sigma-Aldrich) foi dissolvido em DMSO e liberada água potável ad libitum por um período variando de 16 a 70 semanas. Após 16 semanas, quatro ratos foram selecionados aleatoriamente e mortos. Depois, de seis em seis semanas, quatro animais também foram mortos até 70 semanas. RESULTADOS: A taxa de sobrevivência foi superior a 90 por cento. Ocorreu a indução de dois adenocarcinomas, um carcinoma espinocelular e um sarcoma. A incidência de adenocarcinoma gástrico foi de 4,5 por cento (0,5 a 15). CONCLUSÕES: O modelo experimental de carcinogênese gástrica em ratos Wistar, utilizando MNU dissolvido na água, não mostrou viabilidade prática neste estudo, devido à baixa taxa de adenocarcinoma gástrico que ocorreu.

BACKGROUND: The N-methyl-N-nitrosourea (MNU) is a direct acting carcinogen, inducing tumors in several species in a variety of organs, including stomach of rats. Treatment of MNU in the drinking water for 25-42 weeks selectively induced glandular gastric carcinoma in F344 rats and C3H mice. AIM: To establish an experimental model for selective MNU induction of glandular stomach cancer in Wistar rats. METHODS: A total of 48 males eight-week-old Wistar rats were used in the present study. MNU (Sigma-Aldrich) was dissolved in DMSO and provided as the drinking water ad libitum for a period ranging from 16 to 70 weeks. After 16 weeks, four rats were randomly selected and killed. After every six weeks four animals were killed until 70 weeks. RESULTS: Survival rate was higher than 90 percent. It had the induction of two adenocarcinomas, one squamous cell carcinoma and one sarcoma. The incidence of gastric adenocarcinoma was 4.5 percent (0.5 to 15). CONCLUSIONS: The experimental model of gastric carcinogenesis in Wistar rats, using MNU dissolved in water, showed not practice viability in this study due to the low rate of gastric adenocarcinoma.

Considerações técnicas no treinamento de anastomoses microvasculares em laboratório de microcirurgia: [revisão] / Microvascular anastomosis in the laboratory - technical considerations: [review]

Anastomoses microvasculares são um procedimento cirúrgico complexo e um armamento essencial utilizado em diversas sub especialidades. A primeira etapa de treinamento em anastomose microcirúrgica deve ser sempre no laboratório. Este artigo é uma revisão sobre os fatores envolvidos no para a realização de anastomoses microvasculares. Instrumental cirúrgico, microscópio, estrutura do laboratório, procedimentos cirúrgicos, questões éticas e parâmetros radiológicos e histológicos são discutidos.