Animal models of Kashin-Beck disease exposed to environmental risk factors: Methods and comparisons.

The main etiological mechanism for Kashin-Beck disease (KBD) is deep chondrocyte necrosis induced by environmental risk factors (ERFs). The scholars have conducted several epidemiological, cellular, and animal model studies on ERFs. Gradually, four etiological hypotheses have been formed, including water of organic poisoning hypothesis represented by fulvic acid (FA), biogeochemical hypothesis represented by selenium (Se) deficiency, food mycotoxin poisoning hypothesis represented by T-2 toxin poisoning and compound etiology theory hypothesis. The animal models of KBD have been replicated based on the previous etiological hypotheses. The different species of animals (monkey, rat, dog, pig, chicken, and rabbit) were treated with different ERFs interventions, and the clinical manifestations and pathological changes of articular cartilages were observed. The animals in the experimental group were fed with endemic water, endemic grain, low nutrition, thallium sulfate, FA, Se, T-2 toxin, and iodine. The dose of thallium sulfate was 1154 µg/d; the doses range of FA were 5, 50, 150, 200, and 211 mg/kg; the doses range of Se were 0.00035, 0.00175, 0.005, 0.02, 0.031, 0.1, 0.15, 0.314, 0.5, and 10 mg/kg; the doses range of T-2 toxin were 40, 100, 200, 600, 1000, 1500, 3000, 6000, and 9000 ng/g; and the doses range of iodine were 0.04, 0.18, and 0.4-0.5 µg/g. The sample size ranged from 9 to 230 depending on the interventions and grouping; the follow-up duration ranged from 1 week to 18 months. Moreover, the methods and comparisons of different animal models of KBD had been summarized to provide a useful basis for studying the pathogenesis of KBD. In conclusion, the rhesus monkeys administrated endemic water and grain were susceptible animals to replicate KBD. The rats treated with T-2 toxin combined with Se/nutrition deficiency could be a suitable and widely used animal model.

Early application of low-dose glucocorticoid improves acute respiratory distress syndrome: A meta-analysis of randomized controlled trials.

Previous clinical trials have investigated the effect of glucocorticoid therapy in acute respiratory distress syndrome (ARDS), with controversial results, particularly with regard to the early administration of low dose glucocorticoid. The present meta-analysis aimed to assess whether the application of glucocorticoid was able to reduce mortality in patients with ARDS. A literature search was performed using online databases, including MEDLINE, Embase, Cochrane and CNKI regardless of whether the studies were published in English or Chinese. Following assessment via inclusion and exclusion criteria, two reviewers screened controlled randomized trials which investigated glucocorticoid therapy in ARDS patients and independently extracted data. The quality of all of the included trials was evaluated based on blinding, randomization and other methods. A total of 14 studies with 1,441 patients met the inclusion criteria. The results of the meta-analysis demonstrated that glucocorticoid significantly reduced the overall mortality of patients with ARDS [relative ratio (RR), 0.68; 95% confidence interval (CI), 0.50-0.91; P<0.05], particularly with a low-dose of glucocorticoid (RR, 0.57; 95% CI, 0.39-0.84; P<0.05) at the early phase of ARDS (RR, 0.37; 95% CI, 0.16-0.86; P<0.05), and a longer duration of steroids (RR, 0.44; 95% CI, 0.30-0.64; P<0.05). Administration of steroids also significantly increased the number of days that patients remained alive and were off mechanical ventilation (RR, 3.08; 95% CI, 1.49-4.68; P<0.05) without significantly increasing the novel infection rate (RR, 1.00; 95% CI, 0.44-2.25; P<0.05). Due to inconsistencies and other limitations, the quality of the studies used for the meta-analysis of the effect of glucocorticoid on mortality was low. In conclusion, early use of low dose glucocorticoid may effectively reduce mortality in patients with ARDS. However, this conclusion may be affected by the limited quality of the studies included in the present meta-analysis.

[Relationships of forest fire with lightning in Daxing' anling Mountains, Northeast China].

Forest fire is an important factor affecting forest ecosystem succession. Recently, forest fire, especially forest lightning fire, shows an increasing trend under global warming. To study the relationships of forest fire with lightning is essential to accurately predict the forest fire in time. Daxing' anling Mountains is a region with high frequency of forest lightning fire in China, and an important experiment site to study the relationships of forest fire with lightning. Based on the forest fire records and the corresponding lightning and meteorological observation data in the Mountains from 1966 to 2007, this paper analyzed the relationships of forest fire with lightning in this region. In the period of 1966-2007, both the lightning fire number and the fired forest area in this region increased significantly. The meteorological factors affecting the forest lighting fire were related to temporal scales. At yearly scale, the forest lightning fire was significantly correlated with precipitation, with a correlation coefficient of -0.489; at monthly scale, it had a significant correlation with air temperature, the correlation coefficient being 0.18. The relationship of the forest lightning fire with lightning was also related to temporal scales. At yearly scale, there was no significant correlation between them; at monthly scale, the forest lightning fire was strongly correlated with lightning and affected by precipitation; at daily scale, a positive correlation was observed between forest lightning fire and lightning when the precipitation was less than 5 mm. According to these findings, a fire danger index based on ADTD lightning detection data was established, and a forest lightning fire forecast model was developed. The prediction accuracy of this model for the forest lightning fire in Daxing' anling Mountains in 2005-2007 was > 80%.