When a red blood cell （RBC） is driven by a pressure gradient through a microfluidic channel, its passage or blockage provides a measure of the rigidity of the cell. This has been developed as a means to separate RBC...When a red blood cell （RBC） is driven by a pressure gradient through a microfluidic channel, its passage or blockage provides a measure of the rigidity of the cell. This has been developed as a means to separate RBCs according to their mechanical properties, which are known to change with pathological conditions such as malaria infection. In this study, we use numerical simulations to establish a quantitative connection between the minimum pressure needed to drive an RBC through a contracting microfluidic channel and the rigidity of the cell membrane. This provides the basis for designing such devices and interpreting the experimental data.展开更多
Objective： To investigate the enhancement basis and the mechanisms of solitary pulmonary nodules （SPNs） by comparing the differences in microvascular structure between benign and malignant lesions. Methods： Dynami...Objective： To investigate the enhancement basis and the mechanisms of solitary pulmonary nodules （SPNs） by comparing the differences in microvascular structure between benign and malignant lesions. Methods： Dynamic contrast-enhanced CT scan was performed on 53 patients with SPNs （diameter〈3 cm, 38 peripheral lung cancers, 5 hamartomas, 10 inflammatory lesions） using a Siemens Plus S or a Marconi MX8000 multi slices spiral CT scanner. The time-attenuation curves were interpreted. The microvascular density （MVD） and the continuity of the microvessels＇ basemental membrane in the dissected specimens were observed with the ABC （avldin-biotin complex） immuno-histochemical method in all patients. Results ：The CT enhancement values of lung cancer （49.05± 16.08 HU） and inflammatory lesions （49.59±21.30 HU） were significantly higher than those of hamartoma （8.98±4.56 HU） t=7.48, P〈0.051 t=8.35, P〈0.05）. But the enhancement of lung cancer was similar to that of inflammatory lesions （t=0.76, P±0. 05）. The time attenuation curve of inflammatory lesions tended to increase faster and reached a higher peak compared to the lung cancer, and both of them maintained a high plateau after crossing. The hamartoma showed a slight increase in the time-attenuation curve and demonstrated a lowplateau curve. The MVD of SPNs was positively correlated with CT enhancement （r=0. 8051）. The microvascular counts of peripheral lung cancer （48.45±10. 09） and inflammatory lesions （49. 60±19. 94） were significantly higher than those of hamartoma （8.70±7. 30） （t=11. 64, P〈0.001, t=6. 09, P〈0. 001 ）, but no significant difference was found between lung cancer and inflammatory lesions （t= -0.26, P=0.799）. There was no difference in the continuity of basement membrane between nodules with anen haneement less than 30 HU and those with an enhancement higher than 30HU （X^2=3. 13, P〉0.05 ）. Conclusion： The microvascular counts mainly contribute to the enhancement value of SPNs. The basement membrane is not related to nodule enhancement, but it might influence the pattern of the time-attenuation curve.展开更多
基金supported by the Natural Sciences and Engineering Research Council of Canada (NSERC 05862 and 06541)the Canada Research Chair program+4 种基金support by the Peter Wall Institute for Advanced Studies during his tenure as Wall Scholarsupport by the Chinese Government Award for Outstanding Self-Financed Students Abroadfunding from the Canadian Institutes of Health Research (CIHR 259107, 325373, 322375)the Canadian Blood Services (CIHR-BUC21403-HM)funding from the UBC Four Year Doctoral Fellowship
文摘When a red blood cell （RBC） is driven by a pressure gradient through a microfluidic channel, its passage or blockage provides a measure of the rigidity of the cell. This has been developed as a means to separate RBCs according to their mechanical properties, which are known to change with pathological conditions such as malaria infection. In this study, we use numerical simulations to establish a quantitative connection between the minimum pressure needed to drive an RBC through a contracting microfluidic channel and the rigidity of the cell membrane. This provides the basis for designing such devices and interpreting the experimental data.
文摘Objective： To investigate the enhancement basis and the mechanisms of solitary pulmonary nodules （SPNs） by comparing the differences in microvascular structure between benign and malignant lesions. Methods： Dynamic contrast-enhanced CT scan was performed on 53 patients with SPNs （diameter〈3 cm, 38 peripheral lung cancers, 5 hamartomas, 10 inflammatory lesions） using a Siemens Plus S or a Marconi MX8000 multi slices spiral CT scanner. The time-attenuation curves were interpreted. The microvascular density （MVD） and the continuity of the microvessels＇ basemental membrane in the dissected specimens were observed with the ABC （avldin-biotin complex） immuno-histochemical method in all patients. Results ：The CT enhancement values of lung cancer （49.05± 16.08 HU） and inflammatory lesions （49.59±21.30 HU） were significantly higher than those of hamartoma （8.98±4.56 HU） t=7.48, P〈0.051 t=8.35, P〈0.05）. But the enhancement of lung cancer was similar to that of inflammatory lesions （t=0.76, P±0. 05）. The time attenuation curve of inflammatory lesions tended to increase faster and reached a higher peak compared to the lung cancer, and both of them maintained a high plateau after crossing. The hamartoma showed a slight increase in the time-attenuation curve and demonstrated a lowplateau curve. The MVD of SPNs was positively correlated with CT enhancement （r=0. 8051）. The microvascular counts of peripheral lung cancer （48.45±10. 09） and inflammatory lesions （49. 60±19. 94） were significantly higher than those of hamartoma （8.70±7. 30） （t=11. 64, P〈0.001, t=6. 09, P〈0. 001 ）, but no significant difference was found between lung cancer and inflammatory lesions （t= -0.26, P=0.799）. There was no difference in the continuity of basement membrane between nodules with anen haneement less than 30 HU and those with an enhancement higher than 30HU （X^2=3. 13, P〉0.05 ）. Conclusion： The microvascular counts mainly contribute to the enhancement value of SPNs. The basement membrane is not related to nodule enhancement, but it might influence the pattern of the time-attenuation curve.
