AIM:Survivin, a recently identified member of the inhibitor of apoptosis protein family, is expressed during development and in various human cancers. However, its expression in normal tissues and clinical relevance i...AIM:Survivin, a recently identified member of the inhibitor of apoptosis protein family, is expressed during development and in various human cancers. However, its expression in normal tissues and clinical relevance in cancers are still debated. In the present study, we analyzed the expression of the survivin gene in human primary and metastatic gastric cancer cells as well as in paired epithelial cells from normal gastric mucosa by means of a novel laser capture microdissection (LCM) technique coupled with reverse transcription -polymerase chain reaction (RT-PCR).METHODS: Thirty patients who had undergone gastrectomy with lymph node dissection for gastric cancer without preoperative treatments were included. Neoplastic tissue, metastatic lymph nodes, and apparently uninvolved normal tissue were collected from each patient. LCM-captured 'pure' cell groups were respectively subjected to RT-PCR analysis with primers specific for the survivin gene.RESULTS: Of the paired samples from 30 gastric cancer patients studied, 24 (80%) primary gastric cancer cell groups and 7 (23%) adjacent morphologically 'normal' gastric epithelial cell groups were shown to have a detectable survivin expression. There was a statistically significant difference in suvivin expression between these two groups (P<0.01). Meanwhile, 95% (19/20) of the metastatic gastric cancer cell groups from lymph nodes had a clear expression of the survivin gene. However, no significant correlation between survivin expression and clinicopathological features of gastric cancer was observed in the present study. CONCLUSION: Survivin expression is present in the majority of gastric cancer cell groups obtained by LCM techniques. The high expression rate in metastatic lesions suggests a possible role of survivin in cancer invasiveness and metastasis. It may contribute to the detection of gastric cancer micrometastasis as a potential molecular marker. In addition, the high expression percentage renders survivin a potential target in the therapy for gastric cancer.展开更多
AIM: To verify the effectiveness of denaturing highperformance liquid chromatography (DHPLC) in detecting somatic mutation of p53 gene in gastric carcinoma tissues.The superiority of this method has been proved in the...AIM: To verify the effectiveness of denaturing highperformance liquid chromatography (DHPLC) in detecting somatic mutation of p53 gene in gastric carcinoma tissues.The superiority of this method has been proved in the detection of germline mutations, but it was not very affirmative with respect to somatic mutations in tumor specimens. ST7 gene, a candidate tumor suppressor gene identified recently at human chromosome 7q31.1, was also detected because LOH at this site has also been widely reported in stomach cancer.METHODS: DNA was extracted from 39 cases of surgical gastric carcinoma specimen and their correspondent normal mucosa. Seven fragments spanning the 11 exons were used to detect the mutation of p53 gene and the four exons reported to have mutations in ST7 gene were amplified by PCR and directly analyzed by DHPLC without mixing with wild-type allele.RESULTS: In the analysis of p53 gene mutation, 9 aberrant DHPLC chromatographies were found in tumor tissues, while their normal-adjacent counterparts running in parallel showed a normal shape. Subsequent sequencing revealed nine sequence variations, 1 polymorphism and 8 mutations including 3 mutations not reported before. The mutation rate of p53 gene (21%) was consistent with that previously reported. Furthermore, no additional aberrant chromatography was found when wild-type DNA was added into the DNA of other 30 tumor samples that showed normal shapes previously. The positivity of p53 mutations was significantly higher in intestinal-type carcinomas (40 %) than that in diffuse-type (8.33 %) carcinomas of the stomach. No mutation of ST7 gene was found.CONCLUSION: DHPLC is a very convenient method for the detection of somatic mutations in gastric carcinoma. The amount of wild type alleles supplied by the non-tumorous cells in gastric tumor specimens is enough to form heteroduplex with mutant alleles for DHPLC detection. ST7 gene may not be the target gene of inactivation at 7q31 site in gastric carcinoma.展开更多
AIM: To study the effect of cyclin G2 on proliferation of gastric adenocarcinoma cell line-SGC-7901 cell in vitro.METHODS: By use of cation lipofectamine transfection reagent,the pIRES-G2 and pIRESneo plasmids were tr...AIM: To study the effect of cyclin G2 on proliferation of gastric adenocarcinoma cell line-SGC-7901 cell in vitro.METHODS: By use of cation lipofectamine transfection reagent,the pIRES-G2 and pIRESneo plasmids were transferred into SGC-7901cell line. Anticlones were selected by G418. Positive clones were observed and counted using Giemsa staining.Cell proliferative ability was assayed by Ml-r.RESULTS: (1) The done number of pIRES-G2 group decreased,clone volume reduced. The number of cell clones in pIRESneo group was 87+3, that of pIRES-G2 group was 53+4,occupying 60.1% of pIRESneo group, there was significant difference obviously (P<0.01, t=15.45). (2) The average absorbance of clone cell obtained by stable transfection of pIRES-G2 at 570 nm was 1.6966+0.2125, the average absorbance of clone cell obtained by stable transfection of pIRESneo at 570 nm was 2.1182+0.3675, there was significant difference between them (P<0.01, t=3.412).CONCLUSION: Cyclin G2 can inhibit SGC-7901cell proliferative ability obviously, it may be a negative regulator in cell cycle regulation.展开更多
The effect of trace amount of active element Si on the wetting and interface characteristics of 1Cr18Ni11Nb/TiO was investigated. Based on the results, a new binder phase for TiO based cermets imitated gold materials ...The effect of trace amount of active element Si on the wetting and interface characteristics of 1Cr18Ni11Nb/TiO was investigated. Based on the results, a new binder phase for TiO based cermets imitated gold materials was developed, and the related mechanisms were studied. The results indicated that there was small wet-ability of the 1Cr18Ni11Nb alloy on TiO, and the interface binding strength of 1Cr18Ni11Nb/TiO was low. 1.5%Si in 1Cr18Ni11Nb could not only make the alloy wet TiO, but also lead to mutual dissolving near the interface, forming high interface binding strength and matching with the thermal expansion coefficient of TiO.展开更多
LOCATED in the northwest of southwest China＇s Yunnan Province, Lijiang has two faces - one scenic, and the other urban. Its multifaceted nature makes it a perfect Valentine＇s Day destination for sun-seeking couples ...LOCATED in the northwest of southwest China＇s Yunnan Province, Lijiang has two faces - one scenic, and the other urban. Its multifaceted nature makes it a perfect Valentine＇s Day destination for sun-seeking couples and singles alike.展开更多
A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated that fon3 acted as a single recessive gene. Microscopic observation showed that the ...A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated that fon3 acted as a single recessive gene. Microscopic observation showed that the number of floral organs in fon3 increased centripetally. For example, the number of pistils was the more frequently increased than organs in the outer whorls. Homeotic conversion of lodicules and glumes into palea/lemma-like organs was observed in some flowers. Scanning electron microscopy observation showed that the size of flower meristems was maintained the same or similar until the lemma primordium started to differentiate, at which time the floral meristem became enlarged, suggesting abnormal development of the inner whorls of rice florets. The relationship of fon3 with other similar rice mutants is discussed.展开更多
基金Supported by the Nationa 1973 Program of China,No.G 1998051203,the National Science Fund for Distinguished Young Scholars of China,No.30125017,and the MOE TRAPOYT Program of China,No.1999-96
文摘AIM:Survivin, a recently identified member of the inhibitor of apoptosis protein family, is expressed during development and in various human cancers. However, its expression in normal tissues and clinical relevance in cancers are still debated. In the present study, we analyzed the expression of the survivin gene in human primary and metastatic gastric cancer cells as well as in paired epithelial cells from normal gastric mucosa by means of a novel laser capture microdissection (LCM) technique coupled with reverse transcription -polymerase chain reaction (RT-PCR).METHODS: Thirty patients who had undergone gastrectomy with lymph node dissection for gastric cancer without preoperative treatments were included. Neoplastic tissue, metastatic lymph nodes, and apparently uninvolved normal tissue were collected from each patient. LCM-captured 'pure' cell groups were respectively subjected to RT-PCR analysis with primers specific for the survivin gene.RESULTS: Of the paired samples from 30 gastric cancer patients studied, 24 (80%) primary gastric cancer cell groups and 7 (23%) adjacent morphologically 'normal' gastric epithelial cell groups were shown to have a detectable survivin expression. There was a statistically significant difference in suvivin expression between these two groups (P<0.01). Meanwhile, 95% (19/20) of the metastatic gastric cancer cell groups from lymph nodes had a clear expression of the survivin gene. However, no significant correlation between survivin expression and clinicopathological features of gastric cancer was observed in the present study. CONCLUSION: Survivin expression is present in the majority of gastric cancer cell groups obtained by LCM techniques. The high expression rate in metastatic lesions suggests a possible role of survivin in cancer invasiveness and metastasis. It may contribute to the detection of gastric cancer micrometastasis as a potential molecular marker. In addition, the high expression percentage renders survivin a potential target in the therapy for gastric cancer.
基金National Science Fund for Distinguished Young Scholars,No.30125017the Major State Basic Research Development Program of China(973 Program),No.G1998051203
文摘AIM: To verify the effectiveness of denaturing highperformance liquid chromatography (DHPLC) in detecting somatic mutation of p53 gene in gastric carcinoma tissues.The superiority of this method has been proved in the detection of germline mutations, but it was not very affirmative with respect to somatic mutations in tumor specimens. ST7 gene, a candidate tumor suppressor gene identified recently at human chromosome 7q31.1, was also detected because LOH at this site has also been widely reported in stomach cancer.METHODS: DNA was extracted from 39 cases of surgical gastric carcinoma specimen and their correspondent normal mucosa. Seven fragments spanning the 11 exons were used to detect the mutation of p53 gene and the four exons reported to have mutations in ST7 gene were amplified by PCR and directly analyzed by DHPLC without mixing with wild-type allele.RESULTS: In the analysis of p53 gene mutation, 9 aberrant DHPLC chromatographies were found in tumor tissues, while their normal-adjacent counterparts running in parallel showed a normal shape. Subsequent sequencing revealed nine sequence variations, 1 polymorphism and 8 mutations including 3 mutations not reported before. The mutation rate of p53 gene (21%) was consistent with that previously reported. Furthermore, no additional aberrant chromatography was found when wild-type DNA was added into the DNA of other 30 tumor samples that showed normal shapes previously. The positivity of p53 mutations was significantly higher in intestinal-type carcinomas (40 %) than that in diffuse-type (8.33 %) carcinomas of the stomach. No mutation of ST7 gene was found.CONCLUSION: DHPLC is a very convenient method for the detection of somatic mutations in gastric carcinoma. The amount of wild type alleles supplied by the non-tumorous cells in gastric tumor specimens is enough to form heteroduplex with mutant alleles for DHPLC detection. ST7 gene may not be the target gene of inactivation at 7q31 site in gastric carcinoma.
基金Supported by a grant for Distinguished Young Teachers of HigherEducation of the Ministry of Education of the Teaching and ResearchEncouragement Plan
文摘AIM: To study the effect of cyclin G2 on proliferation of gastric adenocarcinoma cell line-SGC-7901 cell in vitro.METHODS: By use of cation lipofectamine transfection reagent,the pIRES-G2 and pIRESneo plasmids were transferred into SGC-7901cell line. Anticlones were selected by G418. Positive clones were observed and counted using Giemsa staining.Cell proliferative ability was assayed by Ml-r.RESULTS: (1) The done number of pIRES-G2 group decreased,clone volume reduced. The number of cell clones in pIRESneo group was 87+3, that of pIRES-G2 group was 53+4,occupying 60.1% of pIRESneo group, there was significant difference obviously (P<0.01, t=15.45). (2) The average absorbance of clone cell obtained by stable transfection of pIRES-G2 at 570 nm was 1.6966+0.2125, the average absorbance of clone cell obtained by stable transfection of pIRESneo at 570 nm was 2.1182+0.3675, there was significant difference between them (P<0.01, t=3.412).CONCLUSION: Cyclin G2 can inhibit SGC-7901cell proliferative ability obviously, it may be a negative regulator in cell cycle regulation.
文摘The effect of trace amount of active element Si on the wetting and interface characteristics of 1Cr18Ni11Nb/TiO was investigated. Based on the results, a new binder phase for TiO based cermets imitated gold materials was developed, and the related mechanisms were studied. The results indicated that there was small wet-ability of the 1Cr18Ni11Nb alloy on TiO, and the interface binding strength of 1Cr18Ni11Nb/TiO was low. 1.5%Si in 1Cr18Ni11Nb could not only make the alloy wet TiO, but also lead to mutual dissolving near the interface, forming high interface binding strength and matching with the thermal expansion coefficient of TiO.
文摘LOCATED in the northwest of southwest China＇s Yunnan Province, Lijiang has two faces - one scenic, and the other urban. Its multifaceted nature makes it a perfect Valentine＇s Day destination for sun-seeking couples and singles alike.
文摘A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated that fon3 acted as a single recessive gene. Microscopic observation showed that the number of floral organs in fon3 increased centripetally. For example, the number of pistils was the more frequently increased than organs in the outer whorls. Homeotic conversion of lodicules and glumes into palea/lemma-like organs was observed in some flowers. Scanning electron microscopy observation showed that the size of flower meristems was maintained the same or similar until the lemma primordium started to differentiate, at which time the floral meristem became enlarged, suggesting abnormal development of the inner whorls of rice florets. The relationship of fon3 with other similar rice mutants is discussed.
