False-Negative Results of Real-Time Reverse-Transcriptase Polymerase Chain Reaction for Severe Acute Respiratory Syndrome Coronavirus 2: Role of Deep-Learning-Based CT Diagnosis and Insights from Two Cases

The epidemic of 2019 novel coronavirus, later named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is still gradually spreading worldwide. The nucleic acid test or genetic sequencing serves as the gold standard method for confirmation of infection, yet several recent studies have reported false-negative results of real-time reverse-transcriptase polymerase chain reaction (rRT-PCR). Here, we report two representative false-negative cases and discuss the supplementary role of clinical data with rRT-PCR, including laboratory examination results and computed tomography features. Coinfection with SARS-COV-2 and other viruses has been discussed as well.

An investigation on fluorosis awareness of children aged 8 - 12 in coal-burning type endemic fluorosis in Guizhou Province / 中华地方病学杂志

Objective To survey on fluorosis awareness of children aged 8 - 12 in coal-burning type endemic fluorosis in key diseased districts of Guizhou Province, and to provide a basis for school health education. Methods In 2014, five towns were selected according to five locations as east, south, west, north and center of 23 key diseased districts of Guizhou Province, one complete primary school in each town was chosen to survey on fluorosis awareness of all the children aged 8 - 12. At the same time, datas of fluorosis knowledge awareness of 23 counties in 2010 were collected and compared with the results of this survey. Results In 2014, the students awareness knowledge on endemic fluorosis was 84.21% (247518/293940). The awareness of 9 counties was higher than 90%, 5 counties ranged from 80% to 90%, and 9 counties lower than 80%. Compared with 2010 (awareness:96.58%), 21.74%(5/23) of the counties with increased awareness, and 78.26%(18/23) of the counties with decreased awareness. In overall qustionnaines object, the awareness rates of fluorosis prevention, correct use of coal-fired stoves, correct maintenance method of coal-fired stoves, method of avoid soot pollution food were 81.91% (48154/58788), 83.72%(82026/97980), 85.11%(66709/78384), and 86.12%(50629/58788), respectively. The awareness rates of children aged 8, 9, 10, 11 and 12 were 80.47%(32359/40215), 83.36%(52581/63075), 85.04%(53882/63360), 84.79% (53328/ 62895), and 85.98% (55368/64395), respectively, the differences were statistically significant (χ2=658.93, P0.05).Conclusions The awareness rate of children aged 8 - 12 in key diseased districts of Guizhou Province is decreased. Work on school health education should be continued, to consolidate control outcomes.

Contents of fluoride in corn and peppers in key regions of coal-burning-borne endemic fluorosis areas in Guizhou Province / 中华地方病学杂志

Objective To investigate the content and changes of fluoride in corn and pepper, to evaluate the effect of prevention and control measures, and to provide a basis for adjusting the prevention and control strategy. Methods In 2013, according to the different directions of east, west, south, north and center, 5 townships were selected from each coal-burning-borne endemic fluorosis areas in all 23 counties (cities, districts), and 3 villages was randomly selected from each township. Household samples of corn and dried pepper in 10 households were collected to detect fluorine content. The results of 14 counties were compared with the 2007 survey data. Results A total of 884 and 3379 samples of corn and pepper were collected, and the median fluorine content was 1.26 and 9.15 mg/kg, the range was 0.50~254.59 mg/kg and 0.50~3701.88 mg/kg, respectively. Compared with the survey data of 2007, the median fluoride content of corn of 14 counties decreased by nearly 50%, and the median amount of pepper was reduced by more than 80%. The differences were statistically significant (mg/kg:corn 1.36 vs 2.63, dried pepper 9.70 vs 55.31, Z = 3.28, 9.13, P<0.05). Conclusion The fluoride content of corn and pepper in Guizhou Province is significantly lower, but it is still relatively high in some coal-burning-borne fluorosis counties (cities, districts).

An epidemiological investigation of dental fluorosis of children aged 8-12 in coal-burning type endemic fluorosis areas in Guizhou Province / 中华地方病学杂志

Objective To investigate the prevalence of dental fluorosis in children aged 8-12 in coalburning-borne endemic fluorosis areas in 23 counties in Guizhou Province,and to evaluate the effects of prevention and control measures.Methods In 2014,five towns were selected according to their location of the east,the south,the west,the north and the center of the 23 counties,one primary school in each town was chosen.All the students aged 8-12 in each school were selected,according to the Diagnosis of Dental Fluorosis (WS/T 208-2011),dental fluorosis was examined.At the same time,the detection rate of dental fluorosis of children aged 8-12 was investigated in 23 counties in 2000 and 2007.Analysis and comparison of the data in 2000,2007 and 2014 were done.Results The total detectable rate of dental fluorosis of children aged 8-12 was 32.31％ (5 803/17 962).The detection rate of 3 counties was lower than 15％,12 counties ranged from 15％ to 30％ and 8 counties more than 30％.Very light,mild,moderate,and severe cases of dental fluorosis cases accounted for 48.39％ (2 808/5 803),30.43％ (1 766/5 803),15.16％ (880/5 803) and 6.01％ (349/5 803).Male and female children's overall detection rate was 33.05％ (3 083/9 329) and 31.51％ (2 720/8 633),the difference was statistically significant (x2=4.86,P ＜ 0.05).The detection rates of dental fluorosis of children aged 8,9,10,11 and 12 were 17.79％ (224/1 259),26.02％ (871/3 348),30.28％ (1 255/4 144),34.07％ (1 595/4 682) and 41.02％ (1 858/4 529),indicating that the detection rate increased with age (x2 =345.78,P ＜ 0.01).After longitudinal comparison of the detection rates of dental fluorosis of children aged 8-12 in 2000,2007 and 2014,we found that 17 counties were gradually decreased (all P ＜ 0.05) except Xiuwen,Weining,Qianxi,Qingzhen,Liuzhi and Xixiu (x2 =0.84,4.19,3.67,5.03,1.98,2.37,all P ＞ 0.05).The ratio of dental fluorosis detection rate ＜ 15％,15％-30％ and ＞ 30％ was accounted for 21.74％ (25/115),32.17％ (37/115) and 46.09％ (53/115),respectively,in the 115 villages.Conclusion The detection rate of dental fluorosis of children aged 8-12 in coal-burning-borne endemic fluorosis areas is significantly dropped,and the comprehensive prevention and control effect is gradually apparent.

An evaluation of stove and its usage in key coal-burning fluorosis areas in Guizhou / 中华地方病学杂志

Objective To investigate the usage of the stoves in the severe endemic areas of coal burning fluorosis, sum up experience timely, find problems and adjust strategy for making prevention and control measures. Methods In 23 counties of Guizhou Province in the severe endemic areas of coal burning fluorosis, a town was selected according to the east, west, south, north and center positions, three villages were selected from each town, and 20 families were selected from each village;household stoves and usage were investigated in 2013. And the data of 14 conties was compared with the survey results of 2007. Results A total of 6 916 families from 341 villages in 115 towns of the 23 counties were investigated. Average utilization rate of coal-fired furnace and electric cooker was relatively high, which was 91.34%(6 317/6 916) and 92.93%(6 427/6 916), respectively. Utilization rate of coal stove, firewood oven, gas stove and liquefied gas stove oven was 7.75% (536/6 916)-21.56%(1 491/6 916). The correct utilization rate of coal-fired furnace was 92.80%(5 862/6 317). The correct utilization rate of coal stove was 66.80%(839/1 256); 92.93%(6 427/6 916)of the families used electric cooker year around. Totally 89.82%(5 674/6 317) of the farmers used iron stove in winter. Compared with those of 2007, in 14 of the counties; the differences of coal-fired furnace, coal stove, firewood oven, electric cooker, gas stove, and liquefied gas stove utilization rate were statistically significant (χ2= 888.35, 6 210.71, 165.54, 9 194.29, 36.98, 729.76, all P<0.05). Conclusion After positive and effective comprehensive treatment for many years, great c hanges have taken place in energy structure, clean energy is widely used, the correct utilization rate of coal-fired stoves is increased, and indoor fluorine pollution caused by coal-burning is under control.

A exploration and application of a quality control method for urinary fluoride detection / 中华地方病学杂志

Objective To analyze the quality control measures on urinary fluoride testing in the implementation,and to provide experience in quality control for testing activities.Method According to the Determination of Fluoride in Urine-Ion Selective Electrode Method (WS/T 89-1996),focusing on ways to complete testing all the samples in a short time,implementing internal quality control measures in the testing before,during and after the implementation by different ways as blank experiment,standard substance detection,personnel parallel experiment,paralleled detection,instrument comparison and sample test repeat,were carried out.Results The test results of blank experiment were lower than the lowest detection limit;the test results of standard material were within the scope of the standard reference,there was no significant difference between the mean value and the reference value (t =0.01,0.00,0.02,all P ＞ 0.05),|Z| values were all less than 1;the results of personnel parallel experiment,paralleled detection,instrument comparison test results and sample test repeat were not significantly different statistically (all P ＞ 0.05);the results of instrument comparison and sample test repeat were not significantly different statistically (t =0.129,0.034,all P ＞ 0.05).A total of 9 123 urine samples were tested,the geometric mean of urinery fluoride was 0.58 mg/L.Conclusion Different quality control measures should be implemented through all the testing,control personnel errors,instruments,and reagents,etc,to ensure the quality of the entire test results.

An investigation of coal-burning-borne endemic fluorosis followed comprehensive control in Guizhou / 中华地方病学杂志

Objective To observe the effects of comprehensive prevention and control measures through the trend change analysis of the prevalence of dental fluorosis of children and urinary fluoride in Guizhou.Methods Three villages were selected in each county from Qianxi,Pu'an and Renhuai,in 2009,2011 and 2013.Dental fluorosis of all children aged 8-12 were examined using the reference Diagnosis of Dental Fluorosis (WS/T 208-2011);50 children were selected randomly from each village to detect urinary fluoride content according to the reference Determination of Fluoride in Urine-ion Selective Electrode Method (WS/T 89-1996).Results The detectable rates of dental fluorosis of children aged 8-12 from Qianxi,Pu'an and Renhuai were 53.20％ (490/921),89.97％ (547/608) and 51.73％ (629/1 216),respectively,in 2009,46.68％ (281/602),63.60％ (332/522) and 43.84％ (530/1 209),respectively,in 2011 and 34.04％ (256/752),14.29％ (80/560) and 26.97％ (243/901),respectively,in 2013,and the detection rate in each county was reduced year by year (x2 =60.46,674.96,125.95,all P ＜ 0.01).In 2009,3 counties' urinary fluoride levels of children aged 8-12 were (1.21 ± 1.29),(0.89 ± 0.80) and (1.00 ± 0.59) mg/L,respectively,which were significantly higher than those of 2013 [(0.94 ± 0.52),(0.68 ± 0.26) and (0.87 ± 0.33) mg/L,t =3.743,4.778,3.743,all P ＜ 0.01].Conclusions The dental fluorosis prevalence and urinary fluorine content of children aged 8-12 are falling obviously through comprehensive prevention and control measures.The target to control and eliminating the disease of endemic fluorosis is not reached.It should be continue to strengthen management after comprehensive prevention and control measures.

An evaluation of the effectiveness of prevention and control measures on coal-burning-borne endemic fluorosis in Guizhou Province / 中华地方病学杂志

Objective To evaluate the effects of health education and improved stoves on control of coalburning-borne endemic fluorosis in Guizhou Province.Methods In 2014,according to the detectable rate of dental fluorosis of children aged 8-12 before implementing control measures,11 counties were divided into three layers:low detection rate (detection rate was less than 60％),medium detection rate (detection rate from 60％ to 90％) and high detection rate (detection rate was greater than 90％).One county was selected from each layer and two towns were selected in each county.According to the Diagnosis of Dental Fluorosis (WS/T 208-2011),dental fluorosis of all children aged 8-12 was examined in all towns;At the same time,in the 2 villages in each town,20households and students of one class in grade 4 to 6 were selected to survey knowledge about prevention and control of coal-burning-borne endemic fluorosis;and to survey the situation of improved stoves,drying and elutriation of corn and chillies,and related life behavior.Results The detectable rate of dental fluorosis of children aged 8-12was 5.49％ (198/3 607),8.33％ (72/864),12.46％ (179/1 437),and it was significantly lower than before implementing control measures [41.88％ (931/2 223),61.91％ (4 863/7 855),91.25％(2 439/2 673),x2 =1 166.43,909.56,2 508.96,all P ＜ 0.01].Correct answer rates of students about knowledge on endemic fluorosis were 78.03％ (792/1 015),84.93％ (1 465/1 725) and 80.18％ (910/1 135),the correct answer rates of knowledge were significantly higher than those before implementing control measures [23.19％ (640/2 760),47.41％ (2 368/4 995) and 40.25％ (3 405/8 460),x2 =947.96,736.61,644.69,all P ＜ 0.01].Correct answer rates of family householders about knowledge on endemic fluorosis were 86.75％ 047/400),95.25％ (381/400) and 86.25％ (345/400),the correct answer rates of knowledge were higher than those before implementing control measures [17.78％ (80/450),37.20％ (279/750) and 25.27％ (139/550);x2 =402.97,359.49,344.55,all P ＜ 0.01].The percentages of households whose stoves were qualified and can be used correctly to the total households were 96.25％ (77/80),96.25％ (77/80) and 93.75％ (75/80),and before implementing control measures [4.92％ (348/7 078),21.51％ (7 461/34 693) and 6.73％ (475/7 062)],and the differences were statistically significant (x2 =1 181.55,262.63,842.82,all P ＜ 0.01).The percentages of households using clean energy in heating season to the total households increased from 0 (0/7 078),0 (0/34 693),0(0/7 062) to 98.75％ (79/80),98.75％ (79/80),96.25％ (77/80).The rates of the three counties whose inhabitants could bake the chillies correctly were 96.25％ (77/80),95.00％ (76/80) and 97.50％ (78/80),which were significantly higher than before implementing control measures [5.55％(5/90),26.00％ (39/150),52.73％ (58/110),x2=139.52,99.36,45.64,all P ＜ 0.01].Who cooked chillies after washing were 93.75％ (75/80),95.00％ (76/80),93.75％ (75/80),which were significantly higher than before implementing control measures [74.44％ (67/90),87.33％ (131/150),34.55％ (38/110),x2 =11.47,3.91,67.36,all P ＜ 0.05].Conclusion The effects of health education and improving stoves on coal-burning-borne endemic fluorosis in the three counties of Guizhou Province are remarkable.

Advances in cerebral microbleeds / 国际脑血管病杂志

Cerebral microbleeds are new biomarkers of the cerebral small vascular disease.With the development of neuroimaging techniques,the related research of cerebral microbleeds has been paid more and more attention.The research of the correlation between cerebral microbleeds and cognitive impairment and stroke,imaging features,pathological changes,and clinical outcomes can provide an important basis for clinical treatment decisions.

Quality analysis of urinary fluoride detection ability from 2010 to 2012 in Guizhou endemic fluorosis monitoring network laboratories / 中华地方病学杂志

Objective To evaluate the urinary fluorine detection quality of endemic fluorosis monitoring network laboratories in Guizhou Province and promote the improvement of quality control.Methods From 2010 to 2012,according to the method for determination of fluoride in urine by ion selective electrode,in 11 endemic fluorosis monitoring network laboratories in Guizhou,an quality control assessment was done.In the internal quality control assessment,standard substance detection inspection was used for personnel parallel samples and equipment comparison,t test was used to compare the inter-group differences.In the external quality control inspection,blind urine fluorine sample was tested,and a Z score value evaluation method was used to compare the relative error of the test results.Results In the assessment of internal quality control,the parallel comparison test results of sample,personnel and instrument showed that the differences were not statistically significant (t =-1.81-1.80,P ＞ 0.05).In 2010,in the external quality control inspection,there was 1 laboratory |Z|≥3,and 2 test results |Z| ＞2;in 2011,there was 4 test results |Z| ＞ 2;in 2012,there was 5 test results |Z| ＞ 2;in 2010,there was one laboratory in a blind test,relative error of the results ＞ 20％;in 2011 and 2012,there was a laboratory in a blind test,relative error of the results ＞ 10％.Conclusion The endemic fluorosis monitoring network laboratory testing ability in Guizhou is relatively good,but there is an obvious individual laboratory system error.

An analysis of the monitoring results of coal-burning-borne endemic fluorosis in Pu'an County in 2011-2013 / 中华地方病学杂志

Objective To provide a basis for specific intervention by dynamic observation of the households'related health life behavior and the children fluorosis change trend caused by the coal-burning-borne endemic fluorosis in Pu'an County.Methods Three villages were chosen using simple random sampling method in 2011-2013 for continuous monitoring.Every monitoring year in each monitoring village,according to the principle of every household survey,10 households were selected to survey related health life behavior;,and in the monitoring village all the children aged 8-12 years old were selected for Diagnosis of Dental Fluorosis (WS/T 208-2001),and in each age group,10 urine samples (half male half female) were collected,the fluoride content was determined by the ion selective electrode method (WS/T 89-1996).Results In 2011-2013,the households stoves qualified rate,stoves correct usage rate and the corn or chili correct drying rate were all 100.00％ (30/30).The dental fluorosis incidences of 8-12 years old children were 63.60％ (332/522),25.44％ (173/680) and 14.29％ (80/560),respectively,decreased year by year (x2 =324.67,P ＜ 0.05).In 2011-2013,children urinary fluoride levels were 0.83,0.84 and 0.68 mg/L,respectively.The difference between years was statistically significant (x2 =26.89,P ＜ 0.05),and the level in 2013 was significantly lower than those of 2011 and 2012 (all P ＜ 0.01).Conclusion In 2011-2013,the residents in Pu'an have good health life behavior,and the condition of children's dental fluorosis is decreased year by year.

An evaluation of the effectiveness of prevention and control measures on coal-burning-borne endemic fluorosis in Xishui County of Guizhou Province / 中华地方病学杂志

Objective To evaluate the effectiveness of comprehensive prevention and control measures on coal-burning-borne endemic tluorosis in Xishui,on residents healthy behavior and situation of the disease.Methods In 2013,five towns were selected according to their location of east,south,west,north and centre.Three villages and one elementary school in each town were chosen,and 20 families' related behavior and fluorine prevention knowledge questionnaire in each village were surveyed.All the students from one class aged 8-12 of grade 3-6 in each school were selected,according to the Diagnosis of Dental Fluorosis,dental fluorosis was examined and fluorine knowledge questionnaire was surveyed.At the same time,the detection rate of dental fluorosis of children aged 8-12,information of the knowledge about prevention and cure of fluorosis and related behavior of target groups in 2007,and the urinary fluoride contents of children aged 8-12 in 2000 were collected.Analysis and comparison of the data in 2000,2007 and 2013 were done.Results After the intervention,the witting rates of students and family householders 90.95％ (11 773/12 945),84.27％ (3 792/4 500),were significantly higher than those of before the intervention [19.29％ (1 039/5 385),26.27％ (394/1 500),x2 =9 279.14,1 794.22,all P ＜ 0.01].Proper utilization rate of cooking stove was 100.00％ (37/37),iron stove utilization rate was 99.64％ (279/280),dry chili correct rate was 100.00％ (299/299) and before the intervention,these values were 3.20％ (43/1 345),90.28％ (1 207/1 337)and 62.14％ (855/1 376),respectively,and the differences were statistically significant (x2 =601.12,27.28,27.28,all P ＜ 0.01).Children's dental fluorosis detection rate was 24.21％ (206/851),compared with that of before the intervention,61.62％ (2 150/3 489),the difference was statistically significant (x2 =385.93,P ＜ 0.01).Children's urine fluoride was (0.51 ± 0.29) mg/L,and before the intervention [(1.55± 1.59) mg/L],the difference was statistically significant (t'=10.25,P ＜ 0.01).Conclusions The effect of comprehensive prevention and control measures against coal-burning-borne endemic fluorosis in Xishui are remarkable.The residents health related behavior has been formed and the condition is reduced markedly.

A epidemiological study of children's dental fluorosis in coal-burning-borne endemic fluorosis areas of three counties in Guizhou Province / 中华地方病学杂志

Objective To explore the changes of children's dental fluorosis before and after implementation of comprehensive prevention and control intervention in coal-burning-borne endemic fluorosis areas of Guizhou Province,and to provide a scientific basis for making corresponding prevention and control measures.Methods In 2010,according to a simple random cluster sampling method,1/5 of the villages out of 1/5 of the towns of Zunyi,Kaiyang and Longli Counties,were selected as investigation sites for inspection of dental fluorosis in 8-12 years old children and a longitudinal comparison was done with historical related dental fluorosis (year 1986 and 2000).Dental fluorosis of children was diagnosed by Dean method.Results In Zunyi,Kaiyang and Longli Counties,the detection rates of 8-12 years old children's dental fluorosis were 23.76％(202/850),15.77％ (79/501) and 11.17％(42/376),respectively.The detection rates of dental fluorosis in the 8,9,10,11 and 12 years old age group of children were 11.52％(19/165),17.19％(44/256),20.20％ (81/401),18.61％ (75/403) and 20.72％ (104/502),respectively,and there was no significant difference between groups (x2 =2.90,P ＞ 0.05).The survey results of this investigation in the three counties in 2000 were 34.20％(7 805/22 821),39.77％(1 782/ 4 481),60.88％(2 806/4 609),and the differences were statistically significant between the results of 2010 and 2000(x2 =37.81,110.91,350.76,all P ＜ 0.01).And compared with the results of 1986[34.29％ (9 463/27 596),36.30％ (2 708/7 460),35.72％ (1 896/5 308)],the difference of Zunyi County was not statistically significant (x2 =0.045,P ＞ 0.05),but for Kaiyang and Longli the differences were statistically significant(x2 =14.35,626.39,all P ＜ 0.01).Conclusions The effect of comprehensive prevention and control intervention is very obvious.In the 3 counties,the incidence rates of 8-12 years old children's dental fluorosis are already dropped to below 30％ of the control standard.Subsequent management should be carried out and the state of disease should be evaluated for organization-assessment acceptance in accordance with relevant hygiene standards in a planned way.

Prevalence of coal-burning-fluorosis by factor analysis in Guizhou Province / 中华地方病学杂志

Objective To investigate the epidemic situation of coal-burning-fluorosis,and to explore key areas for implementing prevention and control measures in Guizhou Province.Methods Survey data of dental fluorosis of children aged 8-10,anti-fluoride knowledge and health-related behaviors of target students and their families before implementing the comprehensive disease control measures in 2010,were analyzed and evaluated using the method of factor analysis in 23 diseased districts.Results ①The three main factors (F) related to the endemic of coal-burning-fluorosis were economic factor (F 1),knowledge factor (F2) and behavior factor (F3):F1 included the detection rate of 8 to 12 years old children's dental fluorosis,iron stove ownership,corn correct drying rate and chili correct drying rate; F2 included stove correct utilization rate,students awareness and head of the household awareness; F3 included corn food washing rate before cooking and chili food washing rate.②In the economic factor score arrangement,the first three were Zunyi,Xiuwen and Qingzhen.In the F2 score arrangement,the first three were Zunyi,Xishui and Xixiu.In the F3 score arrangement,the first three was Liuzhi,Bijie and Xixiu.③After comprehensive score,Zunyi,Qingzhen,Xishui,Xixiu,Puding and Liuzhi Counties were found to be relatively stronger in control of the epidemic of coal-burning-fluorosis; Xiuwen,Renhuai,Guanling and so on 13 counties were found to be relatively moderate,and Tongzi,Hezhang,Shuicheng and Nayong Counties were found to be relatively weak.Conclusions ①The endemic of coal-burning-fluorosis is related with many factors,and the indexes we selected in this study have a strong correlation and sensitivity,which may be used in evaluating the prevention effect of control measures to coal-buming-fluorosis.②The endemic of coal-burning-fluorosis in Guizhou Province is quite different,and key prevention and control measures can be applied according to a comprehensive factor analysis.

Evaluation of the prevention and control measures on coal-burning endemic fluorosis in Guizhou 2013 / 中华地方病学杂志

Objective Through investigation of children fluorosis illness,family households improved stoves and related life styles,to provide a scientific basis for sustainable control of endemic fluorosis.Methods In 2013,in Huishui County and Baiyun District,3 towns were selected in each county(district),and 3 villages were selected in each town.All 8-12 years old children in the school of these villages were checked dental fluorosis,which was diagnosed according to Dental Fluorosis Diagnosis (WS/T 208-2011); at the same time,10 families were selected to survey the situation of improved stoves and related life styles.Results Dental fluorosis detection rate of 8-12 years old children in Huishui and Baiyun were 2.75％ (23/836) and 2.26％ (11/487),which were all lower than 30％.Qualified rate of improved stoves and qualified stoves correct utilization rate were all 100.0％ (90/90).For human consumption,the correct rate of corn drying was 100.0％ (90/90) ; the correct rates of chili drying were 98.9％ (89/90) and 100.0％ (90/90).Conclusions The prevention effect is obvious,which has reached the control standards.We should continue to improve the long-term mechanism of comprehensive control measures,and to achieve substantial elimination of coal-burning endemic fluorosis.

Application of Magnetic Resonance Diffusion Tensor Imaging in Intracerebral Hemorrhage (review) / 中国康复理论与实践

@#Intracerebral hemorrhage is a disease with high mortality and morbidity. This article discussed the application of magnetic resonance diffusion tensor imaging for intracerebral hemorrhage clinical research, and its limitations and prospect.

Analysis on the value of the multi-slice spiral CT and MRI scanning for applying to the identifying diagnosis of the new and old vertebral compresion fracture / 中华放射学杂志

Objective To analyze and explore the value of the mutislice spiral CT (MSCT) scanning,its reconstructive technology and MRI scanning for applying to the identifying diagnosis of new and old vertebral compresion fracture.Methods One hundred and sixty-seven cases with the new and old vertebral compresion fracture who have 189 vertebrae in total were examined using the MSCT scanning,their imaging information were postprocessed with 2D and 3D reconstruction at the work station.Thirty-four patients with overall 43 vertebrae were carried out by MRI scanning and their images were compared with those of MSCT.Results They had the highest proportion of vertebrae in L1 with accounting for 27.68% (31/112) and 35.06% (27/77) among the patients with new and old vertebral compresion fracture,respectively.The next was T12,L2 and T11.There were statistically significant differences between new and old cases in such appearance as fracture line clear and sharp(102 and 21),contusion and hemorrhage of spinal cord(15 and 0),parenchyma shadow beside vertebrae(103 and 11),appendant fracture(26 and 5),organ's lacerated wound around vertebral body(30 and 0),discus intervertebrales vacuum(10 and 36),derangement and hardening of vertebral bone trabecularism(29 and 51) (P＜0.01).Twenty-six vertebrae with the uneven low T1 WI signal,27 vertebrae with the T2 WI fat-suppresion irregular high signal were demonstrated in MRI scanning among 27 vertebrae of 21 cases with new vertebral compresion fracture.While 16 vertebrae with the T1WI and T2WI signals were the same as those of the normal vertebrae,16 vertebrae were the T2WI fat-suppresion low signal among 13 cases with old vertebral compresion fracture.Conclusions The MSCT plays an important role in identifying diagnosis for the most of the patients with the new and old vertebral compresion fracture, while MRI scanning may reflect the pathophysiological characteristics in diagnosis of the spinal cord and the ligament lesion.Therefore,the MSCT and MRI scanning should be integrated to be used to enhance remarkably the accurate rate of the diagnosis.

Application of the Kappa statistic in MRI diagnosis of lumbar disk herniation / 中华放射学杂志

Objective To assess the concordance of MRI diagnosis for patients suspected of lumbar disk herniation by using Kappa statistic.Methods One hundred patients(48 males and 52 females)with lumbosaeral radicular pain,aged from 17 to 86(average 61).All patients underwent fast spin-echo T1 and T2 weighted imaging on a 3.0 T MR scanner and spine surface coil.Two radiologists(doctor A and doctor B)evaluated the lumbar disks from L3-4,L4-5.and L5-S1 in 50 out of the 100 patients independently.The presence of a bulging disk or a herniation was reported.Images were interpreted twice:once before and once after disclosure of clinical information.And disks of 52 patients out of the 100 samples were interpreted by the two radiologists independently without clinical information as well.The Kappa statistics was employed to assess the concordance of each radiologist's diagnoses as well as the observer variation of the two radiologists.Results Diagnoses before and after disclosure to clinical information were concordant in 114 disks for doctor A and in 109 for doctor B.respectively.Diagnoses before and after disclosure to clinical information were not concordant in 36 disks for doctor A and in 41 disks for doctor B,respectively.The Kappa values were 0.60±0.06 and 0.57±0.06 for doctor A and doctor B,respectively.The concordance was moderate.After disclosure to elinical information.the numbers of reported bulging disks increased significantly.by 10 and 31 for doctor A and doctor B,respectively.Without clinical information,the diagnoses of the two radiologists were concordant in 77 disks,while not concordant in 79 disks.The interobserver agreement was poor(Kappa=0.24±0.06).The diffcrence on diagenoses made between with and without clinical information mainly happened on the differential diagnosis of normal disks and bulging disks.The different,diagnoses made between with and without clinical information were on 20 disks and on 30 disks for doctor A and doctor B,respectively;that accounted for 55.6%(20/36)and 73.2%(30/41)of total variation respectively.The diagnostic difference between the 2 doctors happened mainly on differentiation of bulging disks and normal disks,which happened in 56 disks,aceountiong for 70.9%(56/79)of total variation.Conclusion Variation on diagnoses of the same radiologist or between tworadiologists was mainly caused by disagreement on bulging disks.

Application of SCGE-FPG in the study of arsenic-induced oxidative DNA damage in PHA-stimulated and unstimulated human lymphocytes / 中华预防医学杂志

<p><b>OBJECTIVE</b>To confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes.</p><p><b>METHODS</b>The alkaline comet assay combined with specific enzyme (Formamidopyrimidine-DNA glycosylase, FPG) digestion was used to measure As-induced base damage.</p><p><b>RESULTS</b>The enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 micromol As for 2 hours. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significantly revealed in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hour repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21 %, respectively, were repaired in unstimulated cells.</p><p><b>CONCLUSIONS</b>As induces oxidative DNA damage in human lymphocytes within micromolar concentrations. Like the damage induced by H(2)O(2), As-induced DNA damage was more slowly repaired in unstimulated lymphocytes.</p>

Arsenic Induces DNA Damage via Reactive Oxygen Species in Human Cells

To elucidate arsenic-induced oxidative DNA damage, the genotoxicity of arsenic in human cells was comparatively studied with single cell gel electrophoresis (SCGE) assay in combination with the observation of the protective effects of dimethyl sulfoxide (DMSO) and catalase. Arsenic, at the concentration of 2.4 μM by coincubation for 24 hours, significantly induced DNA damage in HL60, a human promyelocytic leukemia cell line. In contrast, significant DNA damage was found in human mononucleocytes at the concentration of 4.8 μM or above. The cells were incubated separately with DMSO (12 mM/l), a well-known hydroxyl radical (OH-) scavenger, and catalase (1,300 U/ml), a hydrogen peroxide (H2O2) scavenger, for 6 hours and then further coincubated with various concentrations of arsenic for 24 hours at 37°C and 5% CO2. The findings showed that both DMSO and catalase significantly reduced the arsenic-induced tail moment, a parameter of total damaged DNA, in HL60 and mononucleocytes. Hence our findings indicate that arsenic, with micromolar concentrations, induces typical and various extents of DNA damage in human cells via reactive oxygen species in a dose-dependent manner.