Objective： We investigated the relationship between the expression of Caspase-3, cell proliferation and apoptosis in gastric cancer and their precancerous lesions, to explore the tumorigenesis of the stomach mucosa. ...Objective： We investigated the relationship between the expression of Caspase-3, cell proliferation and apoptosis in gastric cancer and their precancerous lesions, to explore the tumorigenesis of the stomach mucosa. Methods： Caspase- 3 expression in 13 normal gastric mucosa, 6 chronic atrophic gastritis （CAG）, 31 intestinal metaplasia （IM）, 114 dysplasia （DYS） and 20 gastric carcinomas were investigated immunohistochemically. Cell proliferation was evaluated with anti-Ki-67 immunostaining and apoptosis was evaluated using DNA fragmentation in situ by TdT-mediated dUTP biotin nick end labeling （TUNEL） method. Results： Caspase-3 mild-moderately positive expression was observed in most of normal superficial epithelia, its positively polar distribution in normal mucosa, CAG, IM, DYS and gastric carcinomas changed as seen in TU- NEL, and so did the positive rate. Caspase-3 protein expression showed significantly positive correlation with the number of apoptotic cells labeled with TUNEL （correlation coefficient r = 0,94; P 〈 0101）. Ki-67 expression showed a negative but not significant correlation trend with Caspase-3 （correlation coefficient r = -0.23; P 〉 0.05）. Conclusion： Caspase-3 protein expression was up-regulated from CAG to IM and mild-moderate atypical dysplasia, but down-regulated in severe dysplasia and gastric carcinoma, indicating that inactivity or reduced expression of Caspase-3 is closely correlated with carcinogenesis of the stomach mucosa.展开更多
For better detecting the spatial-temporal change mode of individual susceptible-infected-symptomatic-treated-recovered epidemic progress and the characteristics of information/material flow in the epidemic spread netw...For better detecting the spatial-temporal change mode of individual susceptible-infected-symptomatic-treated-recovered epidemic progress and the characteristics of information/material flow in the epidemic spread network between regions,the epidemic spread mechanism of virus input and output was explored based on individuals and spatial regions.Three typical spatial information parameters including working unit/address,onset location and reporting unit were selected and SARS epidemic spread in-out flow in Beijing was defined based on the SARS epidemiological investigation data in China from 2002 to 2003 while its epidemiological characteristics were discussed.Furthermore,by the methods of spatial-temporal statistical analysis and network characteristic analysis,spatial-temporal high-risk hotspots and network structure characteristics of Beijing outer in-out flow were explored,and spatial autocorrelation/heterogeneity,spatial-temporal evolutive rules and structure characteristics of the spread network of Beijing inner in-out flow were comprehensively analyzed.The results show that(1)The outer input flow of SARS epidemic in Beijing concentrated on Shanxi and Guangdong provinces,but the outer output flow was disperse and mainly includes several north provinces such as Guangdong and Shandong.And the control measurement should focus on the early and interim progress of SARS breakout.(2)The inner output cases had significant positive autocorrelative characteristics in the whole studied region,and the high-risk population was young and middle-aged people with ages from 20 to 60 and occupations of medicine and civilian labourer.(3)The downtown districts were main high-risk hotspots of SARS epidemic in Beijing,the northwest suburban districts/counties were secondary high-risk hotspots,and northeast suburban areas were relatively safe.(4)The district/county nodes in inner spread network showed small-world characteristics and information/material flow had notable heterogeneity.The suburban Tongzhou and Changping districts were the underlying high-risk regions,and several suburban districts such as Shunyi and Huairou were the relatively low-risk safe regions as they carried out minority information/material flow.The exploration and analysis based on epidemic spread in-out flow help better detect and discover the potential spatial-temporal evolutive rules and characteristics of SARS epidemic,and provide a more effective theoretical basis for emergency/control measurements and decision-making.展开更多
In this paper, an SIRS epidemic model with high-risk immunization was investigated, where a susceptible neighbor of an infected node is immunized with rate h. Through analyzing the discrete-time model, we found that t...In this paper, an SIRS epidemic model with high-risk immunization was investigated, where a susceptible neighbor of an infected node is immunized with rate h. Through analyzing the discrete-time model, we found that the epidemic threshold above which an epidemic can prevail and persist in a population is inversely proportional to 1 - h value. We also studied the continuous-time epidemic model and obtained a different result： the epidemic threshold does not depend on the immunization parameter h. Our results suggest that the difference between the discrete-time epidemic model and the continuous-time epidemic model exists in the high-risk immunization.展开更多
In this paper, based on a class of multi-group epidemic models of SEIR type with bilinear incidences, we introduce a vaccination compartment, leading to multi-group SVEIR model. We establish that the global dynamics a...In this paper, based on a class of multi-group epidemic models of SEIR type with bilinear incidences, we introduce a vaccination compartment, leading to multi-group SVEIR model. We establish that the global dynamics are completely determined by the basic reproduction number R0V which is defined by the spectral radius of the next generation matrix. Our proofs of global stability of the equilibria utilize a graph-theoretical approach to the method of Lyapunov functionals. Mathematical results suggest that vaccination is helpful for disease control by decreasing the basic reproduction number. However, there is a necessary condition for successful elimination of disease. If the time for the vaccines to obtain immunity or the possibility for them to be infected before acquiring immunity is neglected in each group, this condition will be satisfied and the disease can always be eradicated by suitable vaccination strategies. This may lead to over evaluation for the effect of vaccination.展开更多
基金Supported by grants from the National Natural Science Foundation of China (No. 30070845, 30271607, 30600286)Climbing Scholars of the Universities in Liaoning Province (2009–2011)
文摘Objective： We investigated the relationship between the expression of Caspase-3, cell proliferation and apoptosis in gastric cancer and their precancerous lesions, to explore the tumorigenesis of the stomach mucosa. Methods： Caspase- 3 expression in 13 normal gastric mucosa, 6 chronic atrophic gastritis （CAG）, 31 intestinal metaplasia （IM）, 114 dysplasia （DYS） and 20 gastric carcinomas were investigated immunohistochemically. Cell proliferation was evaluated with anti-Ki-67 immunostaining and apoptosis was evaluated using DNA fragmentation in situ by TdT-mediated dUTP biotin nick end labeling （TUNEL） method. Results： Caspase-3 mild-moderately positive expression was observed in most of normal superficial epithelia, its positively polar distribution in normal mucosa, CAG, IM, DYS and gastric carcinomas changed as seen in TU- NEL, and so did the positive rate. Caspase-3 protein expression showed significantly positive correlation with the number of apoptotic cells labeled with TUNEL （correlation coefficient r = 0,94; P 〈 0101）. Ki-67 expression showed a negative but not significant correlation trend with Caspase-3 （correlation coefficient r = -0.23; P 〉 0.05）. Conclusion： Caspase-3 protein expression was up-regulated from CAG to IM and mild-moderate atypical dysplasia, but down-regulated in severe dysplasia and gastric carcinoma, indicating that inactivity or reduced expression of Caspase-3 is closely correlated with carcinogenesis of the stomach mucosa.
基金supported by National Natural Science Foundation of China(Grant Nos. 40871181 and 41101369)Key Knowledge Innovative Program of Chinese Academy of Sciences (Grant No. KZCX2-EW-318)+2 种基金Jiangxi Provincial Natural Science Foundation (Grant No. 20114BAB215024)Natural Science Youth Foundation of Jiangxi Provincial Office of Education (Grant No. GJJ11073)Open Foundation of Key Laboratory of Poyang Lake Wetland and Watershed Research,Ministry of Education (Grant No.PK2010001)
文摘For better detecting the spatial-temporal change mode of individual susceptible-infected-symptomatic-treated-recovered epidemic progress and the characteristics of information/material flow in the epidemic spread network between regions,the epidemic spread mechanism of virus input and output was explored based on individuals and spatial regions.Three typical spatial information parameters including working unit/address,onset location and reporting unit were selected and SARS epidemic spread in-out flow in Beijing was defined based on the SARS epidemiological investigation data in China from 2002 to 2003 while its epidemiological characteristics were discussed.Furthermore,by the methods of spatial-temporal statistical analysis and network characteristic analysis,spatial-temporal high-risk hotspots and network structure characteristics of Beijing outer in-out flow were explored,and spatial autocorrelation/heterogeneity,spatial-temporal evolutive rules and structure characteristics of the spread network of Beijing inner in-out flow were comprehensively analyzed.The results show that(1)The outer input flow of SARS epidemic in Beijing concentrated on Shanxi and Guangdong provinces,but the outer output flow was disperse and mainly includes several north provinces such as Guangdong and Shandong.And the control measurement should focus on the early and interim progress of SARS breakout.(2)The inner output cases had significant positive autocorrelative characteristics in the whole studied region,and the high-risk population was young and middle-aged people with ages from 20 to 60 and occupations of medicine and civilian labourer.(3)The downtown districts were main high-risk hotspots of SARS epidemic in Beijing,the northwest suburban districts/counties were secondary high-risk hotspots,and northeast suburban areas were relatively safe.(4)The district/county nodes in inner spread network showed small-world characteristics and information/material flow had notable heterogeneity.The suburban Tongzhou and Changping districts were the underlying high-risk regions,and several suburban districts such as Shunyi and Huairou were the relatively low-risk safe regions as they carried out minority information/material flow.The exploration and analysis based on epidemic spread in-out flow help better detect and discover the potential spatial-temporal evolutive rules and characteristics of SARS epidemic,and provide a more effective theoretical basis for emergency/control measurements and decision-making.
基金This research is supported by the National Natural Science Foundation of China （No. 61203153）.
文摘In this paper, an SIRS epidemic model with high-risk immunization was investigated, where a susceptible neighbor of an infected node is immunized with rate h. Through analyzing the discrete-time model, we found that the epidemic threshold above which an epidemic can prevail and persist in a population is inversely proportional to 1 - h value. We also studied the continuous-time epidemic model and obtained a different result： the epidemic threshold does not depend on the immunization parameter h. Our results suggest that the difference between the discrete-time epidemic model and the continuous-time epidemic model exists in the high-risk immunization.
文摘In this paper, based on a class of multi-group epidemic models of SEIR type with bilinear incidences, we introduce a vaccination compartment, leading to multi-group SVEIR model. We establish that the global dynamics are completely determined by the basic reproduction number R0V which is defined by the spectral radius of the next generation matrix. Our proofs of global stability of the equilibria utilize a graph-theoretical approach to the method of Lyapunov functionals. Mathematical results suggest that vaccination is helpful for disease control by decreasing the basic reproduction number. However, there is a necessary condition for successful elimination of disease. If the time for the vaccines to obtain immunity or the possibility for them to be infected before acquiring immunity is neglected in each group, this condition will be satisfied and the disease can always be eradicated by suitable vaccination strategies. This may lead to over evaluation for the effect of vaccination.
