29 research outputs found
Analysis of backward differentiation formula for nonlinear differential-algebraic equations with 2 delays
The individual-cell-based cryo-chip for the cryopreservation, manipulation and observation of spatially identifiable cells. I: Methodology
<p>Abstract</p> <p>Background</p> <p>Cryopreservation is the only widely applicable method of storing vital cells for nearly unlimited periods of time. Successful cryopreservation is essential for reproductive medicine, stem cell research, cord blood storage and related biomedical areas. The methods currently used to retrieve a specific cell or a group of individual cells with specific biological properties after cryopreservation are quite complicated and inefficient.</p> <p>Results</p> <p>The present study suggests a new approach in cryopreservation, utilizing the Individual Cell-based Cryo-Chip (i3C). The i3C is made of materials having appropriate durability for cryopreservation conditions. The core of this approach is an array of picowells, each picowell designed to maintain an individual cell during the severe conditions of the freezing - thawing cycle and accompanying treatments. More than 97% of cells were found to retain their position in the picowells throughout the entire freezing - thawing cycle and medium exchange. Thus the comparison between pre-freezing and post-thawing data can be achieved at an individual cell resolution. The intactness of cells undergoing slow freezing and thawing, while residing in the i3C, was found to be similar to that obtained with micro-vials. However, in a fast freezing protocol, the i3C was found to be far superior.</p> <p>Conclusions</p> <p>The results of the present study offer new opportunities for cryopreservation. Using the present methodology, the cryopreservation of individual identifiable cells, and their observation and retrieval, at an individual cell resolution become possible for the first time. This approach facilitates the correlation between cell characteristics before and after the freezing - thawing cycle. Thus, it is expected to significantly enhance current cryopreservation procedures for successful regenerative and reproductive medicine.</p
Tratamento cirúrgico da fratura-avulsão da inserção tibial do L.C.P. do joelho: experiência de 21 casos Surgical treatment of avulsion fractures of the knee PCL tibial insertion: experience with 21 cases
Avaliamos 21 pacientes, sendo 16 pacientes do sexo masculino e 5 do feminino, com idade média de 30 anos, foram submetidos à tratamento cirúrgico da fratura-avulsão do LCP. Em 57% dos casos a lesão foi secundária a acidente motociclÃstico e 19% a acidente automobilÃstico. Em 72% dos casos foi identificada uma lesão na face anterior do joelho. O tratamento cirúrgico consistiu na abordagem posterior do joelho e fixação do fragmento ósseo com parafuso e arruela em 18 casos; e amarrilhas trans-ósseas em 3 casos, onde o fragmento ósseo era muito pequeno. Em 91% dos casos, a cirurgia foi realizada dentro dos primeiros 15 dias apos a lesão. Os pacientes foram avaliados objetivamente (teste de gaveta posterior) e subjetivamente (Escala de Lysholm), apos um seguimento pós-operatório mÃnimo de 12 meses. A análise estatÃstica não mostrou diferença significativa, ao nÃvel de 5%, entre as avaliações objetiva e subjetiva. A ausência de lesão ligamentar periférica pode ter contribuÃdo para que os resultados clÃnicos pós-operatórios tenham avaliação subjetiva satisfatória; entretanto, a presença de uma posteriorização tibial residual sugere que a fratura-avulsão do ligamento cruzado posterior deve ser abordada não como uma lesão óssea pura, mas sim, como uma lesão ósteo-ligamentar.<br>We assessed 21 patients (16 males and 5 females), with mean age of 30 years who underwent surgical treatment for PCL avulsion fracture. In 57% of the cases, injuries were secondary to motorcycle accidents and 19% resulted from car accidents. Injuries on knee's anterior surface were detected in 72% of the cases. The surgical procedure involved posterior approach and bone fragment fixation using nut and screw in 18 cases, the trans-bone suture loop fixation in 3 cases with small bone fragments. In 91% of the cases, surgery was performed within the first two weeks following injury. The patients were objectively (posterior drawer test) and subjectively (Lysholm scale) re-evaluated after a minimum follow-up period of 12 postoperative months. The statistical analysis of objective and subjective assessments did not demonstrate any significant difference (p = 0.05). The satisfactory results of the subjective clinical postoperative evaluation may have been due to the absence of peripheral ligament injury. However, the presence of residual tibial posteriorization suggests that the avulsion fracture of the PCL should be treated as bone-ligament injury, and not just as a bone lesion