Diethylnitrosamine (DENA) is able to induce various benign and malignant liver lesions in rats with a high success rate and a low mortality rate. It provides a more appropriate model that better simulates the various ...Diethylnitrosamine (DENA) is able to induce various benign and malignant liver lesions in rats with a high success rate and a low mortality rate. It provides a more appropriate model that better simulates the various lesions occurring in humans than the usual model of tumor implantations. The aim of the present study was to evaluate MRI liver examination in Sprague-Dawley(SD) rats as a routine method to detect hepatocellular carcinoma (HCC) nodules induced by DENA and to follow up their growth. METHODS:Hepatic carcinogenesis was induced in 80 male SD rats using oral DENA solution. All animals were imaged for liver tumor detection with a 1.5 Tesla magnet (Siemens Sonata,Erlangen, Germany) using correspondence scan parameters and a radio-frequency knee coil. Macroscopic examinations were performed along the axial MRI sections to evaluate magnetic resonance imaging (MRI) findings, and histopathological assessment was also performed. RESULTS:No false negative results were obtained on MR images. Hepatic tumors in 72 rats were confirmed macro-scopically and 68 rats were detected by MRI till the 20th week. The smallest and the largest nodules detected by MRI were 2 mm and 37 mm in diameter respectively. The agreement rate of MRI with macroscopic observation was 39. 1% and 97. 4% respectively for 2 mm to 5 mm and more than 5 mm nodules. CONCLUSIONS:The hepatic tumor induced by DENA provides a more representative range of tumors for imaging diagnosis and interventional treatment. MRI is the best approach for scrutinizing pathological changes of rat livers in the period of observation.展开更多
It is generally assumed that behavior results from an interaction between susceptible genes and environmental stimuli during critical life stages.The present article reviews the main theoretical and practical concepts...It is generally assumed that behavior results from an interaction between susceptible genes and environmental stimuli during critical life stages.The present article reviews the main theoretical and practical concepts in the research of gene environment interaction,emphasizing the need for models simulating real life complexity.We review a novel approach to study gene environment interaction in which a brief post-natal interference with the expression of multiple genes,by hindering the activity of the ubiquitous transcription factor specificity protein 1(Sp1) is followed by later-in-life exposure of rats to stress.Finally,this review discusses the role of peripheral processes in behavioral responses,with the Sp1 model as one example demonstrating how specific behavioral patterns are linked to modulations in both peripheral and central physiological processes.We suggest that models,which take into account the tripartite reciprocal interaction between the central nervous system,peripheral systems and environmental stimuli will advance our understanding of the complexity of behavior.展开更多
基金This study was supported by grants from specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) (20030b10090)China Medical Board of New York (CMB 82-412) the TCM Administration Bureau of Sichuan Province (TCM 2004 B03).
文摘Diethylnitrosamine (DENA) is able to induce various benign and malignant liver lesions in rats with a high success rate and a low mortality rate. It provides a more appropriate model that better simulates the various lesions occurring in humans than the usual model of tumor implantations. The aim of the present study was to evaluate MRI liver examination in Sprague-Dawley(SD) rats as a routine method to detect hepatocellular carcinoma (HCC) nodules induced by DENA and to follow up their growth. METHODS:Hepatic carcinogenesis was induced in 80 male SD rats using oral DENA solution. All animals were imaged for liver tumor detection with a 1.5 Tesla magnet (Siemens Sonata,Erlangen, Germany) using correspondence scan parameters and a radio-frequency knee coil. Macroscopic examinations were performed along the axial MRI sections to evaluate magnetic resonance imaging (MRI) findings, and histopathological assessment was also performed. RESULTS:No false negative results were obtained on MR images. Hepatic tumors in 72 rats were confirmed macro-scopically and 68 rats were detected by MRI till the 20th week. The smallest and the largest nodules detected by MRI were 2 mm and 37 mm in diameter respectively. The agreement rate of MRI with macroscopic observation was 39. 1% and 97. 4% respectively for 2 mm to 5 mm and more than 5 mm nodules. CONCLUSIONS:The hepatic tumor induced by DENA provides a more representative range of tumors for imaging diagnosis and interventional treatment. MRI is the best approach for scrutinizing pathological changes of rat livers in the period of observation.
文摘It is generally assumed that behavior results from an interaction between susceptible genes and environmental stimuli during critical life stages.The present article reviews the main theoretical and practical concepts in the research of gene environment interaction,emphasizing the need for models simulating real life complexity.We review a novel approach to study gene environment interaction in which a brief post-natal interference with the expression of multiple genes,by hindering the activity of the ubiquitous transcription factor specificity protein 1(Sp1) is followed by later-in-life exposure of rats to stress.Finally,this review discusses the role of peripheral processes in behavioral responses,with the Sp1 model as one example demonstrating how specific behavioral patterns are linked to modulations in both peripheral and central physiological processes.We suggest that models,which take into account the tripartite reciprocal interaction between the central nervous system,peripheral systems and environmental stimuli will advance our understanding of the complexity of behavior.
