The correlation of sleep duration and insomnia with low muscle mass, strength and quality in Chinese adults / 中华流行病学杂志

Objective: To explore the relationship of sleep duration and insomnia with muscle mass, strength, and quality in Chinese adults. Methods: Based on the second resurvey of China Kadoorie Biobank (CKB) in 2013-2014, logistic regression models were used to analyze the correlation of sleep duration, insomnia, and its duration with low muscle mass, handgrip strength, and muscle quality. Results: The average sleep duration of the study population was (7.4±1.5) hours. Morbidities of short sleep duration (<6 hours), long sleep duration (≥9 hours), and insomnia were 9.3%,17.4%,and 29.9%,respectively. Compared with those who slept for 7- hours, those who slept for ≥9 hours were more likely to have low muscle mass, low handgrip strength,and low arm muscle quality (AMQ), and the OR (95%CI) of low appendicular skeletal muscle mass index (ASMI), low total skeletal muscle mass index (TSMI), low grip strength and low AMQ were 1.32 (1.18-1.48),1.26 (1.13-1.41), 1.33 (1.18-1.49) and 1.16 (1.03-1.30), respectively. Compared with participants without insomnia, insomnia patients were more likely to have low muscle mass,and the longer the duration of insomnia,the higher the risk (P for trend <0.001). Participants who reported <6 hours sleep duration and insomnia had a higher proportion of low ASMI and low TSMI,compared with those who slept for 7- hours and without insomnia, the OR (95%CI) were 1.26 (1.08-1.47) and 1.25 (1.07-1.46), respectively. Conclusions: Participants who reported ≥9 hours sleep duration were more likely to have low muscle mass,low handgrip strength,and low AMQ. Participants with insomnia had lower muscle mass, and the longer the duration of insomnia, the higher the proportion of low ASMI and low TSMI.

The correlation of physical activity and sedentary leisure time with low muscle mass, strength, and quality in Chinese adults / 中华流行病学杂志

Objective: To explore the relationship of physical activity and sedentary leisure time with muscle mass, strength, and quality in Chinese adults. Methods: Based on the second resurvey of China Kadoorie Biobank (CKB) in 2013-2014, logistic regression models were used to analyze the correlation of physical activity and sedentary leisure time with low muscle mass, grip strength, and muscle quality. Results: A total of 24 245 participants were included in the analysis. The average daily physical activity level was (18.3±13.8) MET-h/d, and the sedentary leisure time was (4.4±1.9) hours. We took the lowest physical activity quartile as the reference and found that the participants' physical activity was negatively correlated to low muscle mass, strength, and quality. The ORs (95%CIs) of low appendicular skeletal muscle mass index (ASMI), low total skeletal muscle mass index (TSMI), low grip strength and low arm muscle quality (AMQ) were 0.68 (0.60-0.77), 0.66 (0.58-0.75), 0.82 (0.72-0.94) and 0.84 (0.74-0.95), respectively. The subtypes of physical activity, including those related to work, transportation, housework, and leisure, also showed negative correlations with low muscle mass, strength, and quality to varying degrees. Compared with participants with the shortest sedentary leisure time, those who had the longest were more likely to have low TSMI (OR=1.13, 95%CI: 0.99-1.30). Conclusions: Physical activity was negatively correlated with a lower risk of low muscle mass and strength, while longer sedentary leisure time positively correlated with low muscle mass.

Differentiation of adult mouse mesenchymal stem cells into hepatocytes cultured in a conditioned culture medium of injured hepatocytes / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To establish a method through which murine bone marrow mesenchymal stem cells (MSCs) can be induced into hepatocytes in vitro.</p><p><b>METHODS</b>A conditioned medium of injured hepatocytes (with CCl4 in vivo) was used to culture the isolated MSCs. The differentiated cells were identified by morphological observation, reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence assay (for AFP, Albumin, and CK18) and periodic acid schiff reaction (PAS) for glycogen.</p><p><b>RESULTS</b>The differentiated cells showed characteristics of hepatocytes. PT-PCR detected AFP mRNA on day 5 and it increased gradually until day 15, and then decreased; CK18 mRNA was detected on day 10; TAT was detected on day 20. Immunofluorescence assay for AFP, albumin and CK18 showed positive staining reactions on day 20. PAS positive glycogen granules appeared in the cytoplasm of the differentiated cells.</p><p><b>CONCLUSION</b>MSCs of adult mice cultured in a conditioned medium of injured hepatocytes can differentiate into hepatocytes. This method can be used in further studying of the mechanism of transdifferentiation of MSCs into hepatocytes.</p>