The objective of this study was to further establish and confirm the relationship of adipose mitochondrial biogenesis in diabetes/obesity and the effects of rosiglitazone (RSG), a peroxisome proliferator-activated receptor (PPAR) ␥ agonist, by systematically analyzing mitochondrial gene expression and function in two mouse models of obesity and type 2 diabetes. Using microarray technology, adipose mitochondrial gene transcription was studied in db/db, high-fat diet-fed C57BL/6 (HFD) and respective control mice with or without RSG treatment. The findings were extended using mitochondrial staining, DNA quantification, and measurements of citrate synthase activity. In db/db and HFD mice, gene transcripts associated with mitochondrial ATP production, energy uncoupling, mitochondrial ribosomal proteins, outer and inner membrane translocases, and mitochondrial heat-shock proteins were decreased in abundance, compared with db/؉ and standardfat diet-fed control mice, respectively. RSG dose-dependently increased these transcripts in both db/db and HFD mice and induced transcription of mitochondrial structural proteins and cellular antioxidant enzymes responsible for removal of reactive oxygen species generated by increased mitochondrial activity. Transcription factors, including PPAR coactivator (PGC)-1, PGC-1␣, estrogen-related receptor ␣, and PPAR␣, were suppressed in both models and induced by RSG. The effects of RSG on adipose mitochondrial genes were confirmed by quantitative RT-PCR and further supported by mitochondrial staining, mitochondrial DNA quantification, and citrate synthase activity. Adipose mitochondrial biogenesis was overwhelmingly suppressed in both mouse models of diabetes/obesity and globally induced by RSG. These findings suggest an important role of adipose mitochondria in diabetes/obesity and the potential for new treatment approaches targeting adipose mitochondria. Diabetes 56:1751-1760, 2007 P eroxisome proliferator-activated receptor (PPAR) ␥ agonists, including rosiglitazone (RSG), are effective drugs for the treatment of type 2 diabetes. It is well established that RSG induces adipogenesis and causes body-wide lipid repartitioning by increasing adipose triglyceride content, thereby lowering free fatty acids, glycerol, triglycerides, and glucose in the circulation, which is associated with increased insulin sensitivity of the liver, muscle, and other organs. Critical to this process, adipose tissue, which highly expresses PPAR␥, serves not only as a lipid storage depot but also as an endocrine organ producing adipokines that regulate the activity of other tissues (rev. in 1,2).There has been growing interest in exploring the involvement of adipose mitochondria in the regulation of whole-body energy homeostasis (3-9). Recent studies suggest that diabetes/obesity is accompanied by a decrease in the expression of adipose mitochondrial genes in ob/ob mice (8) and impaired adipose mitochondria in db/db mice (9) and that the compromised mitochondrial conditions in ob/ob and db/db mice were reversi...
Alpine grassland and the soil on which it is growing in the Qinghai‐Tibetan Plateau (QTP) of China is being degraded in an attempt to increase food and feed production for an increasing global population. Our objective was to use soil quality assessment to quantify changes in soil chemical and physical properties at three depth increments (0 to 4, 4 to 10, and 10 to 20 cm) and thus determine the linkages between soil and vegetation changes, the soil element(s) limiting grassland restoration in alpine region, and the ability to restore soil fertility by reestablishing grasslands. The soil and vegetation were sampled in the different types of degraded grasslands, that is, moderately degraded grassland (MDG), heavily degraded grassland (HDG) and severely degraded grassland (SDG) as well as in the reestablished grasslands at different ages, that is, 5‐yr restored grassland (5yRG), 7‐yr restored grassland (7yRG), and 9‐yr restored grassland (9yRG) for comparative study. The results show: (i) decreased water holding capacity and increased soil hardness as vegetative cover declined, (ii) decreased soil organic carbon (OC) and total nitrogen (TN) and increased total soil potassium, (TK) (iii) the establishment of artificial grassland did not restore soil quality or nutrient stocks within degraded grassland soils, and (iv) yearly variations in soil properties at different depths were significant along the degree of grassland degradation. Significant variations of soil physical and chemical parameters might be attributed to loss of the top soil and changes of vegetation composition and soil and textures. Soil quality can be used to assess grassland degradation and restoration in the alpine region. In conclusion, better soil management is needed for restoring the degraded alpine grasslands on the QTP.
Spatial accessibility to medical resources is an integral component of universal health coverage. However, research evaluating the spatial accessibility of healthcare services at the community level in China remains limited. We assessed the community-level spatial access to beds, doctors, and nurses at general hospitals and identified the shortage areas in Shenzhen, one of the fastest growing cities in China. Based on hospital and population data from 2016, spatial accessibility was analyzed using several methods: shortest path analysis, Gini coefficient, and enhanced 2-step floating catchment area (E2SFCA). The study found that 99.9% of the residents in Shenzhen could get to the nearest general hospital within 30 min. Healthcare supply was much more equitable between populations than across communities in the city. E2SFCA scores showed that the communities with the best and worst hospital accessibility were found in the southwest and southeast of the city, respectively. State-owned public hospitals still dominated the medical resources supply market and there was a clear spatial accessibility disparity between private and public healthcare resources. The E2SFCA scores supplement more details about resource disparity over space than do crude provider-to-population ratios (PPR) and can help improve the efficiency of the distribution of medical resources.
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