ABSTRACT
Objective@#To investigate the anti-photoaging effects of human umbilical cord mesenchymal stem cells derived extracellular vesicles (hucMSC-EVs) on dermal fibroblasts.@*Methods@#Human fibroblasts were pretreated with hucMSC of different concentrations for 24 hours before ultraviolet B (UVB) irradiation. Immediately post irradiation, the intracellular reactive oxygen species (ROS) were analyzed using reactive oxygen detection kit. After 72 hours irradiation, cell proliferation was assessed using CCK-8 assay, and the percentage of senescent cells was evaluated by β-galactosidase (SA-β-gal) staining.@*Results@#The UVB irradiation increased intracellular ROS level, decreased the cell proliferation from 100% to(77.33±2.89)%, and increased the percentage of SA-β-gal positive senescent cells from (6.70±0.46)% to (17.67±1.53)%. The hucMSC-EVs pretreatment decreased the intracellular ROS level, stimulated cell proliferation from (77.33±2.89)% to (90.67±2.52)% and( 96.00±5.57)% , and decreased the positive rate of SA-β-gal positive cells from (17.67±1.53)% to (8.38±0.56)% and (7.07±1.10)%.@*Conclusions@#The hucMSC-EVs preconditioning may protect dermal fibroblasts from UVB induced photoaging, by reducing intracellular ROS.
ABSTRACT
Purpose To propose a definition based algorithm for segmenting and counting cell microscopic images. Materials and Methods Cell microscopic images were first pretreated and then transformed using discrete cosine transformation (DCT). The high frequency part was truncated and re-converted to differentiate clear and blurred images. The clear foreground regions were obtained. The intact objective was extracted using region growing method. Statistics and analysis of cell number were then conducted. Results This algorithm showed good performance in cell microscopic image counting with accuracy of over 90% at less than 100 ms/image. Conclusion Definition based method is fast and accurate in cell microscopic image segmentation and counting.
ABSTRACT
Purpose This study examined the effect of pre-exercise low and high glycemic index (GI) carbohydrate (CHO) meals on running performance. Methods Eight endurance-trained male runners completed two trials that were separated by at least seven days in a counterbalanced design. Two hours before the run and after an overnight fast, each subject consumed an isocaloric meal containing either low (GI = 37, LGI) or high (GI = 77, HGI) GI CHO foods that provided 1.5 g CHO(kg -1 body mass in random order. Each trial consisted of a 21km performance run on a level treadmill. The subjects were required to run at 70% VO 2max during the first 5km of the run. They then completed the remaining 16km as fast as possible. Results All of the subjects achieved a faster performance time after the consumption of the LGI meal (LGI vs HGI: 98 7? 2 min vs 101 5?2 min, P