BACKGROUND:During the process of acute brain injury after stroke, matrix metaloproteinase can undermine the integrity of vascular basement membrane, promote the migration of neutrophils and inflammatory factors, and cause secondary brain injury. OBJECTIVE:To investigate the activation of matrix metaloproteinase 2/9 and the degradation rule of claudin in rat models of middle cerebral artery ischemia at different ischemic durations. METHODS:Thirty-nine male SD rats were randomly divided into three groups according to different ischemic durations (3, 5 and 7 hours) . Middle cerebral artery occlusion (stroke) model was established using modified suture method,i.e., separation of the external carotid artery, inserting the suture into the internal carotid artery through the external carotid artery, and eventualy reaching the middle cerebral artery. The ischemic duration in these three groups was respectively 3 , 5 and 7 hours. After 2 hours of reperfusion, Zea-Longa score and Ludmila Belayev score, brain infarct area, matrix metaloproteinase 2/9 activities and claudin 5 degradation were determined in each group. RESULTS AND CONCLUSION:With the extension of ischemic duration, brain infarct area gradualy increased, central nervous system damage gradualy aggravated, matrix metaloproteinase 2/9 activities gradualy increased, and claudin-5 expression gradualy decreased. There were significant differences between any two ischemic durations in terms of each of above-mentioned indices. The results indicate that after long duration of ischemia, the progressive damage of brain tissue can cause the gradual increase of activation of matrix metaloproteinase 2/9 and the gradual degradation of claudin 5.

Exercise is one of the important techniques of cardiovascular rehabilitation. Exercise can reduce inflammatory response to improve endothelial function, and improve mitochondrial function to increase myocardial cell activity. For cardiovascular risk factors, exer-cise can promote the activity of lipoprotein, increase the level of high-density lipoprotein;improve the function of insulin receptor to reduce insulin resistance, reduce platelet aggregation and improve endothelial function to reduce blood pressure. For the respiratory system, aerobic exercise can improve the function of respiratory muscle, thus relieve the dyspnea. Exercise can promote the activation of immune factor and increase metabolism, to increase immune function and anti-aging. Resistance exercise can improve mitochondrial function and promote fi-ber type conversion, to improve the function of skeletal muscle system.

Objective: To investigate the gene expresssion changes in normal and degeneration cervical intervertebral disc in rats, providing information for clinical diagnosis and treatment of cervical intervertebral disease.Methods: The models of cervical intervertebral disc degeneration in rats caused by imbalance between the dynamic and static forces was established.cDNA microarray chips containing 512 cDNAs were used to investigate the gene expression pattern in cervical intervertebral disc of rat.The results were scanned and analyzed by computer image analysis,and then subjected to standardization,ratio and clustering analysis.Results: Eighteen genes expressed in cervical intervertebral disc were screened out,comprising 11 up regulated and 7 down regulated ones,respectively.This genes expression in cervical spondylosis was similar to other reports.Conclusion: Signal transduction pathways plays an important role in the process of cervical intervertebral disc degeneration.Investigation on the gene expression pattern is helpful for studying degeneration of cervical intervertebral disc pathogenesis.

Objective To evaluate the risk of plague occurrence via surveying and analyzing indoor rat density and flea index in natural villages having previous plague experience. Methods During August to September 2007, 30 natural villages experiencing previous plague were selected based on the surveillance data, and then all households were coded with numbers and 20 households in each village were randomly selected via computer. Cages and sticky papers were set in 600 selected households to capture rats and fleas. Rat density, flea prevalence, flea index and median were estimated. Results One hundred thirty-three Rattus flavipectus and 33 Suncus murinus were caught and averaged rat density was 2.8 rats per one hundred cage. nights (166/6000), the median was 5 rats each village. One hundred and one mice infected fleas, flea prevalence on rats was 60.8% (101/166), 296 Xenopsylla cheopis and 48 Leptopsylla segnis were collected. Rat flea index was 2.1 fleas per rat (344/166). A total of 315 dissociated flea was caught, average dissociated flea index was 0.026 fleas per sticky paper (315/11888). The median was 5.5 dissociated fleas per village. Of dissociated fleas, Ctenocephalides felis felis (205) and Xenopsylla cheopis (103) accounted for 97.8% (308/315). The proportion for species of the rat flea and the dissociated flea was different(Fisher test: P < 0.01). The rat flea was significantly associated with the rat density(r = 0.68, P < 0.01), but the dissociated flea was significantly associated with neither the rat density(r = -yield than fried wheat batter(χ2 = 5.59, P < 0.05). Conclusions In these villages having previous plague experience of Lianghe County, Rattusflavipectus was dominant species of indoor rats, Xenopsylla cheopis and Ctenocephalides felis felis were dominant species of rat flea and dissociated flea, respectively. Mengsong, Bangdu, and Tangjiatun village had potential risk of plague emergence.

Objective To investigate dental caries in 3-year-old children in Jing′an District of Shanghai and analyze the influence of oral cleaning behavior on caries in children. Methods Six hundread 3-year-old children from 12 kindergartens in Jing′an District, Shanghai were randomly selected by cluster sampling method for oral examination, and a self-administered questionnaire survey on children′s oral cleaning behavior was completed by parents.SPSS 22.0 software package was used for statistical analysis. Results Among the 600 children, the prevalence of dental caries was 42.50%, and the average dmft index was 1.76±2.92.Children who did not brush their teeth had a statistically significant increase in rate of dental caries(χ²=29.995, P < 0.001).Children who brushed their teeth for more than three minutes each time had a statistically significant lower rate of caries(χ²=3.918, P=0.048).Children whose parents helped their children brush their teeth every day had a lower rate of caries than those who brushed teeth by themselves, and the difference was statistically significant (χ²=8.718, P=0.013).Logistic regression analysis showed that age of beginning brushing teeth, times of brushing teeth per day and length of brushing teeth per time were all influence factors for caries in children (P < 0.05). Conclusion For the prevention and control of dental caries in 3-year-old, proper oral cleaning behavior is very important.We should make parents as a priority group for doing oral hygiene in children.Schools should strengthen oral health education for parents.Medical institutions should guide and monitor the effectiveness of oral hygiene in children.It is important to reduce the rate of dental caries in preschool children from three aspects:family, school and medical institutions.

OBJECTIVE: The purpose of this experimental stud y was to explore the mechanism of the vertebral osteophyte formation. METHODS: An experimental model of cervical spondylosis in rabbits was established by resection of the cervical supraspinous and interspino us ligaments and detachment of the posterior paravertebral muscles from cerv ical vertebrae. Because of individual difference, the natural development proced ure of the vertebral osteophyte formation could be seen with a microscope by dyn amic observation. RESULTS: The cartilage end-plate was divided into a growth car tilage layer and an articular cartilage layer. Vertebrae and discs from the 3-m onth control group rabbits showed normal structure. The changes of cartilage pla tes from the 3-month experimental group and the 8-month control group animals showed proliferation in peripheral articular cartilage. The osteophytes from the 8-month experimental group animals could be seen. The osteophyte obviously ari sed from proliferation, calcification and ossification of the peripheral articul ar cartilage. CONCLUSIONS: The vertebral osteophyte arises from proliferation of peripheral articular cartilage which undergoes cartilaginous osteophyte, and then changes into bony osteophyte through an endochondral calcification and ossification.

Objective To compare the saccharometabolism with the pancreatic islets functions and insulin resistance index in children with severe stress. Methods Thirty children with severe stress and 30 healthy children in control group were tested. The levels of fasting blood glucose (FBG), fasting insulin (FINS) and fasting C - peptide (FCP) were detected by radioimmunoassay respectively and insulin sensitivity index (ISI), insulin resistance index (IR) and fasting blood cell function index (FBCI) were calculated statistically. Results There were significant differences between the children with severe stress and the normal controls in the levels of FINS, FCP and FBG,(all P0.05). Conclusion There is insulin resistance with the significant decrease in the insulin sensitivity index and significant increase in insulin resistance index in the children with severe stress, which may cause the disorder in glucose metabolism in children with severe stress.

Exosomes are a kind of endosomal vesicles that are secreted by most if not all living cells. Due to their capability of delivering a variety of cargos, such as tissue- or cell-specific proteins, lipids, and genetic materials, and their broad biological activities, exosomes have gained substantial attention as emerging therapeutics. Exosomes derived from mesenchymal stem cells (MSCs) and dendritic cells (DCs) are two types of exosomes that are widely studied. Many preclinical and clinical studies have shown that they have a satisfactory treatment effect in lung diseases, liver diseases, nervous system diseases, tumors, and other diseases. In addition, exosomes from macrophages, tumor cells, plant cells, and many other cells are getting more attention due to their therapeutic potential. Besides natural exosomes, research on engineered exosomes has also made plenty of progress. There have been several engineering methods of exosomes, such as targeting modification and loading of active ingredients. In this review, we summarize the research progress of therapeutic exosomes from different sources, and further discusses the application prospects of exosomes and possible challenges in the future.

To study the chemical constituents from the the deep-sea fungus Alternaria sp. F49. Seven compounds were isolated from the EtOAc extract by using silica gel, Sephadex LH-20, ODS and HPLC methods. Based on the spectroscopic analysis, their structures were identified as (8R)-5-O-methyl-orcinotriol (1), orcinotriol (2), α-acetylorcinol (3), 3'-hydroxyalternariol 5-O-methyl ether (4), altenusiol (5), altenusin (6), and 5'-methoxy-6-methyl-biphenyl-3,4,3'-triol (7). (8R)-5-O-Methyl-orcinotriol (1) is a new phenolic compound which has never been reported in the literature. Compounds 4-7 showed strong DPPH free radical scavenging activity; whereas compounds 1-7 showed strong ABTS free radical scavenging activity.

Military pilot selection is an effective way to lower the training cost, ensure the safety of pilots and aircraft, and improve the military efficiency, which involves a comprehensive evaluation of medical fitness, psychology and flying aptitude of a pilot candidate.The concept and classification of comprehensive evaluation methods were introduced in this paper.Comprehensive evaluation methods used in domestic and overseas military pilot selection were reviewed.Finally, suggestions on the research and application of the military pilot selection system in China were raised.