NRL-AgNP was developed bringing important properties of natural rubber as occlusive membrane with antimicrobial activity of silver nanoparticles. Biological aspects, such as cell viability, tissue reaction, and occlusive membrane performance of NRL-AgNP, are presented. In addition, in vivo degradation was investigated by Fourier Transform Infrared Spectroscopy (FTIR). The cell viability test was performed in mesenchymal stem cells of human deciduous dental pulp seeded with the new material. Tissue reaction was tested through subcutaneous implant of NRL-AgNP and compared to Polytetrafluoroethylene (PTFE) at the dorsum of rats. The performance of the NRL-AgNP as an occlusive membrane in Guided Bone Regeneration (GBR) was tested in full thickness critical size bone defects (8 mm) in rat calvaria. Cell viability was 98.8% for NRL-AgNP and did not result in statistically significant differences compared to negative control (p > 0.05 Kruskal–Wallis). All materials presented similar tissue reaction (p > 0.05). In the GBR experiment, the defects covered with NRL-AgNP presented a more advanced stage of bone regeneration in comparison with non-treated defects. The FTIR spectra of NRL-AgNP before and after implantation showed no degradation of NRL-AgNP membranes. These results are in favor of the NRL-AgNP use as an occlusive membrane for GBR.
Stem cells in platelet-rich plasma (PRP) scaffolds may be a promising treatment for cartilage repair. Human dental pulp stem cell (hDPSC) subpopulations have been identified to have substantial angiogenic, neurogenic and regenerative potential when compared with other stem cell sources. The present study evaluated the potential of hDPSCs in a PRP scaffold to regenerate full-thickness cartilage defects in rabbits. Full-thickness articular cartilage defects were created in the patellar groove of the femur of 30 rabbits allocated into three experimental groups: Those with an untreated critical defect (CTL), those treated with PRP (PRP) and those treated with stem cells in a PRP scaffold (PRP+SC). The patellar grooves of the femurs from the experimental groups were evaluated macroscopically and histologically at 6 and 12 weeks post-surgery. The synovial membranes were also collected and evaluated for histopathological analysis. The synovial lining cell layer was enlarged in the CTL group compared with the PRP group at 6 weeks (P=0.037) but not with the PRP+SC group. All groups exhibited low-grade synovitis at 6 weeks and no synovitis at 12 weeks. Notably, macroscopic grades for the area of articular cartilage repair for the PRP+SC group were significantly improved compared with those in the CTL (P=0.001) and PRP (P=0.049) groups at 12 weeks. Furthermore, histological scores (modified O'Driscoll scoring system) of the patellar groove articular cartilage in the PRP+SC and PRP groups, in which the articular cartilage was primarily hyaline-like, were significantly higher compared with those in the CTL group at 12 weeks (P=0.002 and P=0.007, respectively). The present results support the therapeutic use of hDPSCs for the treatment of full-thickness articular cartilage defects.
As células-tronco apresentam uma alta capacidade de autorregeneração, assim como, um Palavras-chave: Células-tronco cultivadas; controle citogenético; bandamento G; SKY (cariótipo espectral). IntroduçãoAs células-tronco apresentam uma alta capacidade de autorregeneração, assim como um potencial de diferenciação em uma variedade de tipos celulares. Estas células podem ser classificadas como embrionárias e adultas. As células-tronco embrionárias derivam-se do blastocisto e possuem a capacidade de se diferenciarem em todos os tecidos humanos. Um exemplo de células-tronco adultas são as células mesenquimais, as quais estão presentes em uma variedade de tecidos, como medula óssea, tecido adiposo, sangue de cordão umbilical e têm a capacidade de se diferenciarem em ossos, cartilagem, tecido adiposo e musculares, dentre outros. 1,2Apesar de apresentarem propriedades de células-tronco, as mesenquimais apresentam um certo grau de dificuldade no estabelecimento das culturas, podendo perder a expressão da enzima responsável pela imortalização ou enzima telomerase. Vários estudos mostram que os telômeros encurtam-se com o envelhecimento em células humanas somáticas normais e mantêm seu tamanho estável em células tumorais. [3][4][5][6] A regulação do tempo de vida das células humanas in vitro se dá por dois aspectos: a senescência/apoptose e a
BackgroundHematologic neoplasms are associated with mutations in hematopoietic cells and chromosomal abnormalities. During aging, about 2–3% of the elderly have chromosomal abnormalities arising from clonal mosaicism, the immune system is impaired and the bone marrow loses its ability to replace blood cells.ObjectiveTo describe the epidemiological and cytogenetic profile of hematological malignancies, highlighting the frequency of chromosomal alterations in these neoplasms associated with aging.MethodA retrospective cross-sectional study with analysis of karyotype exams results was performed in the Cytogenetic Laboratory of thee Blood Center of the Faculdade de Medicina de Marilia (FAMEMA) between 1998 and 2016. Blood samples from child and adult patients with different hematological malignancies treated in the Onco-hematology Outpatient Clinics of the local blood center and hospitals, and external clinics were tested.ResultsKaryotype exam results of 746 patients with a mean age of 54.7 years (±23.1) were analyzed. The elderly had the highest frequency of hematological malignancies (50.9%), followed by adults (38.3%) and young people (10.7%); elderly women had the highest percentage (55.0%). Normal karyotypes (46,XX/46,XY) were more common (61.8%) compared to abnormal karyotypes, especially among the elderly (56.4%). Myeloproliferative neoplasms were an exception with 67.4% of abnormal karyotypes.ConclusionThere is a higher frequency of hematological malignancies among the elderly. It is possible to conclude that failures in genomic mechanisms and hematopoiesis with aging lead to the formation of cells with the chromosomal alterations found in hematological malignancies.
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