Lipoxygenase(LOX) is related to emergence and development of many diseases, such as acute and chronic inflammation, atherosclerosis, hypertension and tumor. Therefore, the inhibition of LOX may play an important role in the prevention and treatment of these diseases. Many kinds of flavonoids, such as chalcones, flavonols, flavones and flavanols, have inhibitory effect on 5-LOX, 12-LOX and 15-LOX probably through inhibiting expression of LOX, bonding to the enzyme or reacting with free radicals generated at the active site of the enzyme. Their inhibitory activities are related to their structures. The inhibitory effects of flavonoids on LOX maybe one of mechanisms of flavonoids' some biological functions, such as anti-inflammatory, anti-tumor and reducing the risk of cardiovascular disease and cerebrovascular disease.

There is a close relationship between oxidative stress induced tissue damage and many diseases.As a multi-function oxidase,lipoxygenase can generate reactive oxygen species (ROS)by oxidatively metabolizing various endogenous and exogenous chemicals such as drugs and environmental pollutants.Lipoxygense can catalyze endogenous che mical reaction,such as arachidonic acid and pro-duce ROS.Lipoxygenase can be also activated in other ways to generate ROS by activating signal trans-duction.Moreover,some exogenous chemicals can be metabolized into highly reactive radical intermedi-ates by lipoxygenase,inducing ROS generation.The accumulation of intracellar ROS can damage intra-cellar redox balance and induce oxidative stress.That may be one of the possible toxic effect mecha-nis ms of che mical agents.

In recent years, researches on cells, animals, and human beings have found that the carcinogenic mechanism of environmental carcinogen benzo (a) pyrene〔B(a)P〕can reduce methyla?tion of the whole genes, increase the tumor suppressor gene methylation and reduce the gene methyla?tion of proto-oncogene, in addition to the genetic toxicity. It can also cause changes in small RNA expression, the increase of long-chain non-coded RNA expression and imbalance in histone phosphor?ylation expressions. These changes can cause abnormalities in gene expression and chromosome structure and instability, directly leading to cancer. These changes can also cause the corresponding changes of genetic toxicity, such as gene mutation, abnormal genetic damage repair, increas of cell apoptosis and cell cycle arrest. All these are considered to be potential epigenetic mechanisms of B(a)P. Existing researches have provided the scientific basis for the mechanism of and prevention counter?measures for environment-related diseases and vocational diseases caused by B(a)P.

DNA methylation is part of the epigenetic modification process,which can lead to aberrant gene expression. Cytochrome P450 enzyme,cyclooxygenase,lipoxygenase and monoamine oxidase are a class of enzymes produced by human tissues,which are involved in the oxidization pro?cess of endogenous and exogenous chemicals. The methylation patterns of these enzyme genes are dif?ferent between normal tissues and pathological ones. Abnormal methylation patterns will change en?zymes′expression and function,and affect the occurrence and development of diseases. This paper re?viewed the characteristic changes of four oxidative metabolic enzyme genes in certain diseased tis?sues,the impact on methylation status of the metabolic activity of chemicals and on human health. It is hoped that this review can provide a new theoretical basis for the study on the toxic mechanism of chemicals and for diagnosis of diseases.

Dust ; Humans ; Maximum Allowable Concentration ; Occupational Exposure ; adverse effects ; Research Report ; Silicon Dioxide ; toxicity

Humans ; Oxidative Stress ; drug effects ; Oxidoreductases ; metabolism ; physiology

Objective To evaluate the dual blood supply of lung adenocarcinoma and squamous cell carcinoma using dualinput perfusion CT.Methods A total of 40 patients confirmed with lung cancer pathologically underwent CT perfusion (CTP) scanning.The pulmonary flow (PF),bronchial flow (BF),perfusion index (PI,PI=PF/[PF+BF])and tumor volume,location were measured and recorded by 2 experienced radiologists.The differences in CTP parameters between lung adenocarcinomas and squamous cell carcinomas,the central lung cancers and peripheral lung cancers were analyzed.The correlation between the tumor volume and CTP parameters was analyzed.Interobserver agreements were assessed with intraclass correlation coefficient (ICC).Results The average of PF,BF and PI of all 40 cases was (54.26± 21.07)ml/ (min · 100 ml),(64.41±22.06)ml/(min · 100 ml) and (43.38±16.07)％,respectively.Tumor histology was consistent with adenocarcinomas in 23 cases and squamous cell carcinomas in 17 cases,lung adenocarcinomas showed lower PI than that of squamous cell carcinomas (t=-2.196,P=0.034).There were 17 peripheral lung cancers and 23 central lung cancers,and the PI of the peripheral lung cancers was higher than that of the central lung cancer (t=2.305,P=0.027).No statistically significant differences were found for BF and PF between two types of lung cancers and central lung cancers and the peripheral cancers (all P＞0.05).Tumor volume was negatively associated with PI (r =-0.39,P=0.01).Good agreement was found between the two observers,the ICC for BF,PF and PI was 0.97,0.93 and 0.91,respectively.Conclusion Dual-input CTP technique can be used to evaluate the differences of blood supply between different pathological types and locations of lung cancer,with PI depending both on tumor size and location.

Objective To investigate factors related to chronic pain in those injured with fractures 27 months after the Sichuan earthquake.The correlation between intensity of pain and quality of life was also analyzed.Methods A total of 705 victims were investigated on site.Their residual pain was categorized using a visual analogue scale (VAS) score as no pain,mild pain,moderate pain or severe pain.The pain-related biological,psychological and social factors were analyzed using the Barthel Index ( BI ),Life Satisfaction Questionaire-11 ( LiSat-11 )and the SF-36 health questionnaire. Rehabilitation and surgical interventions,employment,income and emotional status were also investigated. Results The incidence of chronic pain was 88.5％ in this population,of which mild pain and moderate pain were 35.7％ and 33.3％,respectively.The percentage of the victims who had received fracture surgery was 65.8％ ; the percentage of those who had recovered was 96.9％.BI scores for the victims without pain,with mild,moderate and severe pain were 92.7 + 10.2,92.8 + 8.4,91.2 ± 9.9 and 90.4 + 14.7,respectively ; the differences between these groups were all statistically insignificant.The influence of pain intensity on life satisfaction showed a significant linear trend.The percentages of the victims with restricted occupational ability in the four groups were 38.3％,61.5％,75.7％ and 62.8％ respectively.The median of personal annual income were ￥ 3550,￥ 2500,￥ 2000 and ￥ 2500.The VAS scores were significantly related to abnormal emotions,life satisfaction,employment and annual income.The subjects with different levels of residual pain also showed significant differences in the physical functioning,role-physical,bodily pain,general health,vitality,social functioning,role-emotional and mental health sub-scales of the SF-36.The total SF-36 scores were highest among victims without pain (70.6 + 17.5) and declined significantly in those with mild (61.3 + 14.3 ),moderate (52.7 + 14.3 ) and severe pain (52.3 + 14.7 ).This negative correlation between pain intensity and SF-36 total score was statistically significant. Conclusions Chronic pain remains common among fracture victims 27 months after the earthquake.Its intensity is correlated with psychological and social factors as well as quality of life.

Objective To study the clinical value of using a four-point method (FP) in measuring joint angles.Method Methods Twenty-five subjects without knee dysfunction were studied.Every knee joint was tested in extension,below 90° of flexion and above 90° of flexion with the traditional three-point method (TP) and the new four-point method.X-rays were taken as a gold standard measurement.The reliability and validity were analyzed using Bland-Altman plots,which can yield 95% limits of agreement (LOA).Results (1) The joint axis centers moved with changes in joint angle.(2) The 95% LOA of inter-tester reliability was (-5.0,2.7) with the FP and (-6.5,4.4) with the TP.The 95% LOAs of intra-tester reliability were (-3.6,4.0) for tester A and (-4.1,4.8) for tester B with the FP,while (-5.0,6.4) for tester A and (-6.1,5.8) for tester B with the TP.(3) The 95% LOAs in the three positions were (3.5,2.6) in extension,(-3.3,3.6) in mild flexion and (-1.9,5.7) in greater flexion with the FP,and ( 6.8,1.1),(-4.0,7.1) and (0,8.5) with the TP.Conclusions The FP gives better reliability and validity than the TP in joint angle measurement.

Objective To make a comparison between the plain radiograph, CT, and MR findings of gouty arthritis and to analyse the relationship between clinical data and imaging findings. Methods Fifty-four joints of 33 patients with a confirmed diagnosis of gouty arthritis were included in this study. In the morning, the blood uric acid level of patients was tested before meal. In the afternoon, their clinical data were recorded and joints were examinated by plain radiography, CT, and MRI. The imaging findings were evaluated by tophi, bone erosion, soft tissue swelling, hydrarthrosis, synovial thickness, and bone oedema. The data was analyzed by Chi-square test, indepentdent-samples t test, and logistic regression. Results The Chi-square test was utilized to evaluate number of joints with tophi(CT>plain radiography, MR>plain radiography, P<0. 01), soft tissue swelling (MR>CT>plain radiography, P<0. 01), hydrarthrosis(MR>CT, P<0. 01). In addition, 35 joints had bone oedema and 50 joints had synovial thickness. The course of disease(tophi positive group vs tophi negative group, P<0. 01) was analyzed by indepentdent-samples t test. The tophi's causative agents including bone erosion and course of disease were analysed by logistic regression(P<0. 01). Conclusions MRI is superior to CT and plain radiography on the early diagnosis of gout. Tophi and bone erosion may not affect the blood uric acid level. With the progression of disease, the probability of tophi formation increases. The relationship between the formation of tophi and bone erosion may be interpromotied.