An experiment was conducted to compare the effects of two mouse thrombocytopenia models induced by cyclophosphamide at two different administration routes to determine a proper cyclophosphamide administration route th...An experiment was conducted to compare the effects of two mouse thrombocytopenia models induced by cyclophosphamide at two different administration routes to determine a proper cyclophosphamide administration route that could cause stable thrombocytopenia. A suitable drug dosage that could induce thrombocytopenia in mouse efficiently with the definite administration route was then investigated. BALB/c mice were randomly divided into Normal, Model A and Model B groups. To Model A, 200 mg/kg of cyclophosphamide was given by vena caudalis injection as first dose and 30 mg/kg as maintenance dose by intraperitoneal injection at the following 6 days. To Model B, 150 mg/kg of cyclophosphamide was given by subcutaneous injection once a day for consecutive 3 days. All groups were under investigation for 15 days. The result suggested that a decrease in the number of blood platelets of Model B at the 7th day were significantly than that of Normal. Other platelet related indices like platelet distribution width, mean platelet volume and platelet-large cell ratio of Model B increased significantly in comparison with those of Normal group. The platelets count was reduced but fluctuated greatly, and more than half of the mice died in Model A. Therefore, subcutaneous injection of cyclophosphamide for 3 days was used for the cyclophosphamide dosage test. BALB/c mice were randomly divided into Normal, cyclophosphamide low dose （100 mg/kg）, medium dose （120 mg/kg） and high dose （140 mg/kg） groups. All groups were under investigation for 11 days. Though all 3 dosages successfully initiated thrombocytopenia as the platelets number dropped at the 7th day, the low dose was considered to be a suitable one that was of high efficacy and low toxicity. Thus, BALB/c mice challenged by subcutaneous injection of cyclophosphamide 100 mg/kg per day for 3 consecutive day is one simple, feasible and stable mouse thrombocytopenia model that could be used for pharmacodynamic test of the drugs which are supposed to have platelets increasing effect.展开更多
AIM： To establish a simple model consisting of the rou- tine laboratory variables to predict both minimal fibrosis and cirrhosis in chronic hepatitis B virus （HBV）-infected patients. METHODS： We retrospectively in...AIM： To establish a simple model consisting of the rou- tine laboratory variables to predict both minimal fibrosis and cirrhosis in chronic hepatitis B virus （HBV）-infected patients. METHODS： We retrospectively investigated 114 chron- ic HBV-infected patients who underwent liver biopsy in two different hospitals. Thirteen parameters were analyzed by step-wise regression analysis and correla- tion analysis. A new fibrosis index [globulin/platelet （GP） model] was developed, including globulin （GLOB） and platelet count （PLT）. GP model = GLOB （g/mL） x 100/PLT （x 109/L）. We evaluated the receiver operating characteristics analysis used to predict minimal fibrosis and compared six other available models. RESULTS： Thirteen clinical biochemical and hemato- logical variables [sex, age, PLT, alanine aminotransfer- ase, aspartate aminotransferase （AST）, albumin, GLOB, total bilirubin （T.bil）, direct bilirubin （D.bil）, glutamyl-transferase, alkaline phosphatase, HBV DNA and pro- thrombin time （PT）] were analyzed according to three stages of liver fibrosis （F0-F1, F2-F3 and F4）. Bivariate Spearman＇s rank correlation analysis showed that six variables, including age, PLT, T.bil, D.bil, GLOB and PT, were correlated with the three fibrosis stages （FS）. Cor- relation coefficients were 0.23, -0.412, 0.208, 0.220, 0.314 and 0.212; and P value was 0.014, 〈 0.001, 0.026, 0.018, 0.001 and 0.024, respectively. Univariate analysis revealed that only PLT and GLOB were signifi- cantly different in the three FS （PLT： F = 11.772, P 〈 0.001; GLOB： F = 6.612, P = 0.002）. Step-wise multiple regression analysis showed that PLT and GLOB were also independently correlated with FS （R2 = 0.237）. By Spearman＇s rank correlation analysis, GP model was significantly correlated with the three FS （r = 0.466, P 〈 0.001）. The median values in F0-F1, F2-F3 and F4 were 1.461, 1.720 and 2.634. Compared with the six available models （fibrosis index, AST-platelet ratio, FIB-4, fibrosis-cirrhosis index and age-AST model and age-PLT ratio）, GP model showed a highest correlation coefficient. The sensitivity and positive predictive value at a cutoff value 〈 1.68 for predicting minimal fibrosis F0-F1 were 72.4% and 71.2%, respectively. The speci- ficity and negative predictive value at a cutoff value 〈 2.53 for the prediction of cirrhosis were 84.5% and 96.7%. The area under the curve （AUC） of GP model for predicting minimal fibrosis and cirrhosis was 0.762 [95% confidence interval （CI）： 0.676-0.848] and 0.781 （95% CI： 0.638-0.924）. Although the differences were not statistically significant between GP model and the other models （P all 〉 0.05）, the AUC of GP model was the largest among the seven models. CONCLUSION： By establishing a simple model using available laboratory variables, chronic HBV-infected patients with minimal fibrosis and cirrhosis can be di- agnosed accurately, and the clinical application of this model may reduce the need for liver biopsy in HBV- infected patients.展开更多
Although multi-stage incremental sheet forming has always been adopted instead of single-stage forming to form parts with a steep wall angle or to achieve a high forming performance, it is largely dependent on empiric...Although multi-stage incremental sheet forming has always been adopted instead of single-stage forming to form parts with a steep wall angle or to achieve a high forming performance, it is largely dependent on empirical designs. In order to research multi-stage forming further, the effect of forming stages(n) and angle interval between the two adjacent stages(Δα) on thickness distribution was investigated. Firstly, a finite element method(FEM) model of multi-stage incremental forming was established and experimentally verified. Then, based on the proposed simulation model, different strategies were adopted to form a frustum of cone with wall angle of 30° to research the thickness distribution of multi-pass forming. It is proved that the minimum thickness increases largely and the variance of sheet thickness decreases significantly as the value of n grows. Further, with the increase of Δα, the minimum thickness increases initially and then decreases, and the optimal thickness distribution is achieved with Δα of 10°.Additionally, a formula is deduced to estimate the sheet thickness after multi-stage forming and proved to be effective. And the simulation results fit well with the experimental results.展开更多
OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activit...OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activity of iridoid glycosides (IGs) in a rat model of carotid artery thrombosis. The effects on coagulation, such as thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT), and the effect on collagen-induced platelet aggregation in vivo were investigated. Rats were intragastrically administered IGs (50, 100 or 200 mg/ kg) twice daily for 3 days. RESULTS: IGs were shown for the first time to have an antithrombotic action through the inhibition of platelet aggregation, with little effect on the coagulation time of peripheral blood. Our results also showed that IGs may significantly and dose-dependently reduce arterial thrombus load in a model of carotid artery thrombosis and inhibit collagen-induced platelet aggregation in rats. IGs (100or 200 mg/kg) had no significant effect on APTT and PT, but did lengthenTT at a higher dose. CONCLUSION: These data, together with the previously reported neuroprotective effects of IGs in rats with cerebral ischemia, suggest that the antithrombotic action of IGs may potentially contribute to the treatment of cerebral ischemic diseases, including cerebral apoplexy.展开更多
This paper is concerned with inference of panel data varying-coefficient partially linear models with a one-way error structure. The model is a natural extension of the well-known panel data linear model （due to Balt...This paper is concerned with inference of panel data varying-coefficient partially linear models with a one-way error structure. The model is a natural extension of the well-known panel data linear model （due to Baltagi 1995） to the setting of semiparametric regressions. The authors propose a weighted profile least squares estimator （WPLSE） and a weighted local polynomial estimator （WLPE） for the parametric and nonparametric components, respectively. It is shown that the WPLSE is asymptotically more efficient than the usual profile least squares estimator （PLSE）, and that the WLPE is also asymptotically more efficient than the usual local polynomial estimator （LPE）. The latter is an interesting result. According to Ruckstuhl, Welsh and Carroll （2000） and Lin and Carroll （2000）, ignoring the correlation structure entirely and ＂pretending＂ that the data are really independent will result in more efficient estimators when estimating nonparametric regression with longitudinal or panel data. The result in this paper shows that this is not true when the design points of the nonparametric component have a closeness property within groups. The asymptotic properties of the proposed weighted estimators are derived. In addition, a block bootstrap test is proposed for the goodness of fit of models, which can accommodate the correlations within groups illustrate the finite sample performances of the Some simulation studies are conducted to proposed procedures.展开更多
基金Supported by the 211 Project of Jinan Universitythe Team Project of Natural Science Foundation of Guangdong Province (8351063201000003)+3 种基金the Popular Science Foundation of Science & Technology Bureau of Guangzhou City (2008KP055)the Natural Science Foundation of Guangdong Province (06025198)the Jinan University Natural Science Foundation (51204017)the Science and Technology Innovation Project for Undergraduates (cx08120)
文摘An experiment was conducted to compare the effects of two mouse thrombocytopenia models induced by cyclophosphamide at two different administration routes to determine a proper cyclophosphamide administration route that could cause stable thrombocytopenia. A suitable drug dosage that could induce thrombocytopenia in mouse efficiently with the definite administration route was then investigated. BALB/c mice were randomly divided into Normal, Model A and Model B groups. To Model A, 200 mg/kg of cyclophosphamide was given by vena caudalis injection as first dose and 30 mg/kg as maintenance dose by intraperitoneal injection at the following 6 days. To Model B, 150 mg/kg of cyclophosphamide was given by subcutaneous injection once a day for consecutive 3 days. All groups were under investigation for 15 days. The result suggested that a decrease in the number of blood platelets of Model B at the 7th day were significantly than that of Normal. Other platelet related indices like platelet distribution width, mean platelet volume and platelet-large cell ratio of Model B increased significantly in comparison with those of Normal group. The platelets count was reduced but fluctuated greatly, and more than half of the mice died in Model A. Therefore, subcutaneous injection of cyclophosphamide for 3 days was used for the cyclophosphamide dosage test. BALB/c mice were randomly divided into Normal, cyclophosphamide low dose （100 mg/kg）, medium dose （120 mg/kg） and high dose （140 mg/kg） groups. All groups were under investigation for 11 days. Though all 3 dosages successfully initiated thrombocytopenia as the platelets number dropped at the 7th day, the low dose was considered to be a suitable one that was of high efficacy and low toxicity. Thus, BALB/c mice challenged by subcutaneous injection of cyclophosphamide 100 mg/kg per day for 3 consecutive day is one simple, feasible and stable mouse thrombocytopenia model that could be used for pharmacodynamic test of the drugs which are supposed to have platelets increasing effect.
文摘AIM： To establish a simple model consisting of the rou- tine laboratory variables to predict both minimal fibrosis and cirrhosis in chronic hepatitis B virus （HBV）-infected patients. METHODS： We retrospectively investigated 114 chron- ic HBV-infected patients who underwent liver biopsy in two different hospitals. Thirteen parameters were analyzed by step-wise regression analysis and correla- tion analysis. A new fibrosis index [globulin/platelet （GP） model] was developed, including globulin （GLOB） and platelet count （PLT）. GP model = GLOB （g/mL） x 100/PLT （x 109/L）. We evaluated the receiver operating characteristics analysis used to predict minimal fibrosis and compared six other available models. RESULTS： Thirteen clinical biochemical and hemato- logical variables [sex, age, PLT, alanine aminotransfer- ase, aspartate aminotransferase （AST）, albumin, GLOB, total bilirubin （T.bil）, direct bilirubin （D.bil）, glutamyl-transferase, alkaline phosphatase, HBV DNA and pro- thrombin time （PT）] were analyzed according to three stages of liver fibrosis （F0-F1, F2-F3 and F4）. Bivariate Spearman＇s rank correlation analysis showed that six variables, including age, PLT, T.bil, D.bil, GLOB and PT, were correlated with the three fibrosis stages （FS）. Cor- relation coefficients were 0.23, -0.412, 0.208, 0.220, 0.314 and 0.212; and P value was 0.014, 〈 0.001, 0.026, 0.018, 0.001 and 0.024, respectively. Univariate analysis revealed that only PLT and GLOB were signifi- cantly different in the three FS （PLT： F = 11.772, P 〈 0.001; GLOB： F = 6.612, P = 0.002）. Step-wise multiple regression analysis showed that PLT and GLOB were also independently correlated with FS （R2 = 0.237）. By Spearman＇s rank correlation analysis, GP model was significantly correlated with the three FS （r = 0.466, P 〈 0.001）. The median values in F0-F1, F2-F3 and F4 were 1.461, 1.720 and 2.634. Compared with the six available models （fibrosis index, AST-platelet ratio, FIB-4, fibrosis-cirrhosis index and age-AST model and age-PLT ratio）, GP model showed a highest correlation coefficient. The sensitivity and positive predictive value at a cutoff value 〈 1.68 for predicting minimal fibrosis F0-F1 were 72.4% and 71.2%, respectively. The speci- ficity and negative predictive value at a cutoff value 〈 2.53 for the prediction of cirrhosis were 84.5% and 96.7%. The area under the curve （AUC） of GP model for predicting minimal fibrosis and cirrhosis was 0.762 [95% confidence interval （CI）： 0.676-0.848] and 0.781 （95% CI： 0.638-0.924）. Although the differences were not statistically significant between GP model and the other models （P all 〉 0.05）, the AUC of GP model was the largest among the seven models. CONCLUSION： By establishing a simple model using available laboratory variables, chronic HBV-infected patients with minimal fibrosis and cirrhosis can be di- agnosed accurately, and the clinical application of this model may reduce the need for liver biopsy in HBV- infected patients.
基金Project(51005258) supported by the National Natural Science Foundation of ChinaProject(CDJZR12130065) supported by the Fundamental Research Funds for the Central Universities,China
文摘Although multi-stage incremental sheet forming has always been adopted instead of single-stage forming to form parts with a steep wall angle or to achieve a high forming performance, it is largely dependent on empirical designs. In order to research multi-stage forming further, the effect of forming stages(n) and angle interval between the two adjacent stages(Δα) on thickness distribution was investigated. Firstly, a finite element method(FEM) model of multi-stage incremental forming was established and experimentally verified. Then, based on the proposed simulation model, different strategies were adopted to form a frustum of cone with wall angle of 30° to research the thickness distribution of multi-pass forming. It is proved that the minimum thickness increases largely and the variance of sheet thickness decreases significantly as the value of n grows. Further, with the increase of Δα, the minimum thickness increases initially and then decreases, and the optimal thickness distribution is achieved with Δα of 10°.Additionally, a formula is deduced to estimate the sheet thickness after multi-stage forming and proved to be effective. And the simulation results fit well with the experimental results.
文摘OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activity of iridoid glycosides (IGs) in a rat model of carotid artery thrombosis. The effects on coagulation, such as thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT), and the effect on collagen-induced platelet aggregation in vivo were investigated. Rats were intragastrically administered IGs (50, 100 or 200 mg/ kg) twice daily for 3 days. RESULTS: IGs were shown for the first time to have an antithrombotic action through the inhibition of platelet aggregation, with little effect on the coagulation time of peripheral blood. Our results also showed that IGs may significantly and dose-dependently reduce arterial thrombus load in a model of carotid artery thrombosis and inhibit collagen-induced platelet aggregation in rats. IGs (100or 200 mg/kg) had no significant effect on APTT and PT, but did lengthenTT at a higher dose. CONCLUSION: These data, together with the previously reported neuroprotective effects of IGs in rats with cerebral ischemia, suggest that the antithrombotic action of IGs may potentially contribute to the treatment of cerebral ischemic diseases, including cerebral apoplexy.
基金supported by the Leading Academic Discipline Program211 Project for Shanghai University of Finance and Economics (the 3rd phase) (No.B803)the Shanghai Leading Academic Discipline Project (No.B210)
文摘This paper is concerned with inference of panel data varying-coefficient partially linear models with a one-way error structure. The model is a natural extension of the well-known panel data linear model （due to Baltagi 1995） to the setting of semiparametric regressions. The authors propose a weighted profile least squares estimator （WPLSE） and a weighted local polynomial estimator （WLPE） for the parametric and nonparametric components, respectively. It is shown that the WPLSE is asymptotically more efficient than the usual profile least squares estimator （PLSE）, and that the WLPE is also asymptotically more efficient than the usual local polynomial estimator （LPE）. The latter is an interesting result. According to Ruckstuhl, Welsh and Carroll （2000） and Lin and Carroll （2000）, ignoring the correlation structure entirely and ＂pretending＂ that the data are really independent will result in more efficient estimators when estimating nonparametric regression with longitudinal or panel data. The result in this paper shows that this is not true when the design points of the nonparametric component have a closeness property within groups. The asymptotic properties of the proposed weighted estimators are derived. In addition, a block bootstrap test is proposed for the goodness of fit of models, which can accommodate the correlations within groups illustrate the finite sample performances of the Some simulation studies are conducted to proposed procedures.
