BACKGROUND It is evident that an accurate evaluation of T and N stage rectal cancer is essential for treatment planning.It has not been extensively investigated whether texture features derived from diffusion-weighted...BACKGROUND It is evident that an accurate evaluation of T and N stage rectal cancer is essential for treatment planning.It has not been extensively investigated whether texture features derived from diffusion-weighted imaging(DWI)images and apparent diffusion coefficient(ADC)maps are associated with the extent of local invasion(pathological stage T1-2 vs T3-4)and nodal involvement(pathological stage N0 vs N1-2)in rectal cancer.AIM To predict different stages of rectal cancer using texture analysis based on DWI images and ADC maps.METHODS One hundred and fifteen patients with pathologically proven rectal cancer,who underwent preoperative magnetic resonance imaging,including DWI,were enrolled,retrospectively.The ADC measurements(ADCmean,ADCmin,ADCmax)as well as texture features,including the gray level co-occurrence matrix parameters,the gray level run-length matrix parameters and wavelet parameters were calculated based on DWI(b=0 and b=1000)images and the ADC maps.Independent sample t-tests or Mann-Whitney U tests were used for statistical analysis.Multivariate logistic regression analysis was conducted to establish the models.The predictive performance was validated by receiver operating characteristic curve analysis.RESULTS Dissimilarity,sum average,information correlation and run-length nonuniformity from DWIb=0 images,gray level nonuniformity,run percentage and run-length nonuniformity from DWIb=1000 images,and dissimilarity and run percentage from ADC maps were found to be independent predictors of local invasion(stage T3-4).The area under the operating characteristic curve of the model reached 0.793 with a sensitivity of 78.57%and a specificity of 74.19%.Sum average,gray level nonuniformity and the horizontal components of symlet transform(SymletH)from DWIb=0 images,sum average,information correlation,long run low gray level emphasis and SymletH from DWIb=1000 images,and ADCmax,ADCmean and information correlation from ADC maps were identified as independent predictors of nodal involvement.The area under the operating characteristic curve of the model reached 0.802 with a sensitivity of 80.77%and a specificity of 68.25%.CONCLUSION Texture features extracted from DWI images and ADC maps are useful clues for predicting pathological T and N stages in rectal cancer.展开更多
Twenty strains of Microcystis Kütz were isolated from different freshwater bodies in China to analyze the diversity, geographical distribution and toxin profiles. Based on whole-cell polymerase chain reaction of ...Twenty strains of Microcystis Kütz were isolated from different freshwater bodies in China to analyze the diversity, geographical distribution and toxin profiles. Based on whole-cell polymerase chain reaction of cpcBA-IGS nucleotlde sequence, the derived neighbor-joining （NJ） and maximum parsimony （MP） trees Indicate that these strains of Microcystis can be divided into four clusters. The strains from south, middle and north region of China formed distinct lineages, suggesting high diversity and a geographical distribution from south to north locations. Moreover, the results being indicating high variable genotypes of the strains of the Microcystis strains from the same lake show that there Is high diversity of Microcystis within a water bloom population. Comparing the results of the present study with those reported for compared with 43 strains of Microcystis from other locations, also reveals Chinese strains have high similarity with those from regions in the North Hemispherical. This suggests that the Microcystis strains In the world might have a geographical distribution. Analysis of 30 strains using the primers MCF/TER and TOX2P/TOX2M showed that there was no correlation between the gene of cpcBA-IGS and the presence of racy. Toxic strains were founded to be predominant in different water bodies throughout China.展开更多
The effects of salt stress on carbohydrate metabolism in Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crusts, were investigated in the present study. Extracellular total carbohydrates and ex...The effects of salt stress on carbohydrate metabolism in Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crusts, were investigated in the present study. Extracellular total carbohydrates and exopolysaccharides （EPS） in the culture medium produced by M. vaginatus increased significantly during the growth phase and reached a maximum during the stationary phase. The production of extracellular carbohydrates also significantly increased under higher salt concentrations, which was attributed to an increase in low molecular weight carbohydrates. In the presence of NaCI, the production of cellular total carbohydrates decreased and photosynthetic activity was impaired, whereas cellular reducing sugars, water-soluble sugars and sucrose content and sucrose phosphate synthase activity increased, reaching a maximum in the presence of 200 mmol/L NaCI. These parameters were restored to original levels when the algae were transferred to a non-saline medium. Sodium and K＋ concentrations of stressed cells decreased significantly and H＋-ATPase activity increased after the addition of exogenous sucrose or EPS. The results suggest that EPS and sucrose are synthesized to maintain the cellular osmOtic equilibrium between the intra-and extracellular environment, thus protecting algal cells from osmotic damage, which was attributed to the selective exclusion of cellular Na＋ and K＋ by H＋-ATPase.展开更多
Hormogonium,which was thought to play an important role in the dispersal and survival of these microorganisms in their natural habitats,is a distinguishable developmental stage of heterocystous cyanobacteria.The prese...Hormogonium,which was thought to play an important role in the dispersal and survival of these microorganisms in their natural habitats,is a distinguishable developmental stage of heterocystous cyanobacteria.The present study examined the effects of different light conditions and sugars on the differentiation ofNostoc sphaeroides Kiitzing to the hormogonia stage.Results showed that differentiation of hormogonia was light dependent in the absence of sugar,but that close to 100%of cyanobacteria differentiated to hormogonia in the presence of glucose or sucrose,irrespective of the light conditions.This differentiation was inhibited,even in the presence of sugars,upon application of an inhibitor of respiration.Following the testing of different sugars,the effects of different lights were examined.It was found that 5-10μmol·m^-2·s^-1 photon flux density was optimal for hormogonia differentiation.One hundred percent differentiation was obtained with white light irradiation,in contrast with irradiation with green light(80%differentiation)and red light(0-10%differentiation).Although they showed different efficiencies in inducing hormogonia differentiation in N.sphaeroides,the green and red radiation did not display antagonistic effects.When the additional aspect of time dependence was investigated through the application of different fight radiations and an inhibitor of protein synthesis,it was found that the initial 6 h of the differentiation process was crucial for hormogonia differentiation.Taken together,these results show that hormogonia differentiation in N.sphaeroides is either a photoregulated or an energy deoendent orocess.展开更多
基金Supported by Research and Development Foundation for Major Science and Technology from Shenyang,No.19-112-4-105Big Data Foundation for Health Care from China Medical University,No.HMB201902105Natural Fund Guidance Plan from Liaoning,No.2019-ZD-0743.
文摘BACKGROUND It is evident that an accurate evaluation of T and N stage rectal cancer is essential for treatment planning.It has not been extensively investigated whether texture features derived from diffusion-weighted imaging(DWI)images and apparent diffusion coefficient(ADC)maps are associated with the extent of local invasion(pathological stage T1-2 vs T3-4)and nodal involvement(pathological stage N0 vs N1-2)in rectal cancer.AIM To predict different stages of rectal cancer using texture analysis based on DWI images and ADC maps.METHODS One hundred and fifteen patients with pathologically proven rectal cancer,who underwent preoperative magnetic resonance imaging,including DWI,were enrolled,retrospectively.The ADC measurements(ADCmean,ADCmin,ADCmax)as well as texture features,including the gray level co-occurrence matrix parameters,the gray level run-length matrix parameters and wavelet parameters were calculated based on DWI(b=0 and b=1000)images and the ADC maps.Independent sample t-tests or Mann-Whitney U tests were used for statistical analysis.Multivariate logistic regression analysis was conducted to establish the models.The predictive performance was validated by receiver operating characteristic curve analysis.RESULTS Dissimilarity,sum average,information correlation and run-length nonuniformity from DWIb=0 images,gray level nonuniformity,run percentage and run-length nonuniformity from DWIb=1000 images,and dissimilarity and run percentage from ADC maps were found to be independent predictors of local invasion(stage T3-4).The area under the operating characteristic curve of the model reached 0.793 with a sensitivity of 78.57%and a specificity of 74.19%.Sum average,gray level nonuniformity and the horizontal components of symlet transform(SymletH)from DWIb=0 images,sum average,information correlation,long run low gray level emphasis and SymletH from DWIb=1000 images,and ADCmax,ADCmean and information correlation from ADC maps were identified as independent predictors of nodal involvement.The area under the operating characteristic curve of the model reached 0.802 with a sensitivity of 80.77%and a specificity of 68.25%.CONCLUSION Texture features extracted from DWI images and ADC maps are useful clues for predicting pathological T and N stages in rectal cancer.
基金Supported by the State Key Basic Research and Development Plan of China （2002CB412306）, the Hi-Tech Research and Development Program of China （2005AA60101005）, the National Natural Science Foundation of China （204070117）, and the Knowledge Innovation Program of the Chinese Academy of Sciences （KSCX2-1-10）.Acknowledgements The authors thank Dr BTett Neilan of the University of New South Wales, Austrailia, for his support in designating the MCF/ TER primer. The authors also thank M r Ching H. Yang of California State University, Fullerton, USA and Dr Renhui Li for their editing and advice on the manuscript.
文摘Twenty strains of Microcystis Kütz were isolated from different freshwater bodies in China to analyze the diversity, geographical distribution and toxin profiles. Based on whole-cell polymerase chain reaction of cpcBA-IGS nucleotlde sequence, the derived neighbor-joining （NJ） and maximum parsimony （MP） trees Indicate that these strains of Microcystis can be divided into four clusters. The strains from south, middle and north region of China formed distinct lineages, suggesting high diversity and a geographical distribution from south to north locations. Moreover, the results being indicating high variable genotypes of the strains of the Microcystis strains from the same lake show that there Is high diversity of Microcystis within a water bloom population. Comparing the results of the present study with those reported for compared with 43 strains of Microcystis from other locations, also reveals Chinese strains have high similarity with those from regions in the North Hemispherical. This suggests that the Microcystis strains In the world might have a geographical distribution. Analysis of 30 strains using the primers MCF/TER and TOX2P/TOX2M showed that there was no correlation between the gene of cpcBA-IGS and the presence of racy. Toxic strains were founded to be predominant in different water bodies throughout China.
基金Supported by the National Natural Science Foundation of China(30500068, 30170112)the Chinese Academy of Sciences(KSCX2-SW-322)
文摘The effects of salt stress on carbohydrate metabolism in Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crusts, were investigated in the present study. Extracellular total carbohydrates and exopolysaccharides （EPS） in the culture medium produced by M. vaginatus increased significantly during the growth phase and reached a maximum during the stationary phase. The production of extracellular carbohydrates also significantly increased under higher salt concentrations, which was attributed to an increase in low molecular weight carbohydrates. In the presence of NaCI, the production of cellular total carbohydrates decreased and photosynthetic activity was impaired, whereas cellular reducing sugars, water-soluble sugars and sucrose content and sucrose phosphate synthase activity increased, reaching a maximum in the presence of 200 mmol/L NaCI. These parameters were restored to original levels when the algae were transferred to a non-saline medium. Sodium and K＋ concentrations of stressed cells decreased significantly and H＋-ATPase activity increased after the addition of exogenous sucrose or EPS. The results suggest that EPS and sucrose are synthesized to maintain the cellular osmOtic equilibrium between the intra-and extracellular environment, thus protecting algal cells from osmotic damage, which was attributed to the selective exclusion of cellular Na＋ and K＋ by H＋-ATPase.
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX1-SW-12)the State Key Basic Research and Development Plan of China(2OO2CB4123O6)the Hi-tech Research and Development(863)Program of China(2OO2AA6O1O13).
文摘Hormogonium,which was thought to play an important role in the dispersal and survival of these microorganisms in their natural habitats,is a distinguishable developmental stage of heterocystous cyanobacteria.The present study examined the effects of different light conditions and sugars on the differentiation ofNostoc sphaeroides Kiitzing to the hormogonia stage.Results showed that differentiation of hormogonia was light dependent in the absence of sugar,but that close to 100%of cyanobacteria differentiated to hormogonia in the presence of glucose or sucrose,irrespective of the light conditions.This differentiation was inhibited,even in the presence of sugars,upon application of an inhibitor of respiration.Following the testing of different sugars,the effects of different lights were examined.It was found that 5-10μmol·m^-2·s^-1 photon flux density was optimal for hormogonia differentiation.One hundred percent differentiation was obtained with white light irradiation,in contrast with irradiation with green light(80%differentiation)and red light(0-10%differentiation).Although they showed different efficiencies in inducing hormogonia differentiation in N.sphaeroides,the green and red radiation did not display antagonistic effects.When the additional aspect of time dependence was investigated through the application of different fight radiations and an inhibitor of protein synthesis,it was found that the initial 6 h of the differentiation process was crucial for hormogonia differentiation.Taken together,these results show that hormogonia differentiation in N.sphaeroides is either a photoregulated or an energy deoendent orocess.
