AIM:To determine,by counting micronucleus (MN) frequencies,whether chromosomal or DNA damage have an effect on the pathogenesis of early colorectal adenocarcinoma (CRC). METHODS:We analyzed MN frequencies in 21 patien...AIM:To determine,by counting micronucleus (MN) frequencies,whether chromosomal or DNA damage have an effect on the pathogenesis of early colorectal adenocarcinoma (CRC). METHODS:We analyzed MN frequencies in 21 patients with CRC,24 patients with colon polyps [10 neoplastic polyps (NP) and 14 non-neoplastic polyps (NNP)] and 20 normal controls. RESULTS:MN frequency was significantly increased in CRC patients and in NP patients compared with controls (3.72 ± 1.34,3.58 ± 1.21 vs 1.97 ± 0.81,P < 0.001). However,there was no difference in the MN frequency between CRC patients and NP patients (P > 0.05). Similarly,there was no difference in the MN frequency between NNP patients (2.06 ± 0.85) and controls (P > 0.05). CONCLUSION:Our results suggest increased chromosome/DNA instabilities may be associated with the pathogenesis of early CRC.展开更多
Unstable repeats are associated with various types of cancer and have been implicated in more than 40 neurode-generative disorders. Trinucleotide repeats are located in non-coding and coding regions of the genome. Stu...Unstable repeats are associated with various types of cancer and have been implicated in more than 40 neurode-generative disorders. Trinucleotide repeats are located in non-coding and coding regions of the genome. Studies of bacteria, yeast, mice and man have helped to unravel some features of the mechanism of trinucleotide expansion. Looped DNA structures comprising trinucleotide repeats are processed during replication and/or repair to generate deletions or expansions. Most in vivo data are consistent with a model in which expansion and deletion occur by different mechanisms. In mammals, microsatellite instability is complex and appears to be influenced by genetic, epigenetic and developmental factors.展开更多
AIM：To study the nuclear microsatellite instability (nMSI) at BAT26 and mitochondral microsalellite instability (mtMSI) in the occurrence and development of hepatocellular carcinoma and the relationship between nMSI ...AIM：To study the nuclear microsatellite instability (nMSI) at BAT26 and mitochondral microsalellite instability (mtMSI) in the occurrence and development of hepatocellular carcinoma and the relationship between nMSI and mtMSI.METHODS: nMSI was observed with PCR and mtMSI with PCR-SSCP in 52 cases of hepatocellular carcinoma.RESULTS:mtMSI was detected in 11 out of the 52 cases of hepatocellular carcinoma (21.2%). Among the 11 cases of hepatocellular carcinoma with mtMSI, 7 occured in one locus and 4 in 2 loci. The frequency of mtMSI in the 52 cases of hepatocellular carcinoma showed no correlation to sex, age,infection of hepatitis B, liver cirrhosis as well as positive AFP of the patients (P>0.05). In addition, nMSI was detected in 3 out of 52 cases of hepatocellular carcinoma (5.8%) and there was no correlation of the incidence of mtMSI to that of nMSI (P>0.05).CONCLUSION:mtMSI may be involved in the coccurrence and development of hepatocellular carcinoma and it is independent of nMSI.展开更多
The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of （E）-13-ocimene. Myrrh was extracted with hexane to avoid inducing c...The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of （E）-13-ocimene. Myrrh was extracted with hexane to avoid inducing changes in the constituents and odor. The main constituent, （E）-L3-ocimene （group A; low boiling point）, and the other constituents （group B; high boiling point） of the hexane extract were separated by bulb-to-bulb distillation. The constituents of groups A and B were analyzed over time by nuclear magnetic resonance analysis and the odors were evaluated. Myrrh＇s odor depended on both the amount of thermally unstable （E）-[3-ocimene, which contributed to the fresh odor, and the constituents of group B （thermally stable）, which contributed to the myrrh-like odor. Six compounds （c^-santalene, （Z）-a-bisabolene, c^-bergamotene, （E）-ct-santalal, c^-photosantalol and campherenol） were isolated from group B. No individual group B component had a myrrh-like odor, although the combined odor of group B was myrrh like. The authors demonstrated that the aroma profile of myrrh depends on the thermal instability of （E）-^-ocimene and a combination of six thermally stable terpenes with similar molecular structures.展开更多
Chromosomal DNA replication is one of the central biological events occurring inside cells. Due to its large size, the replica-tion of genomic DNA in eukaryotes initiates at hundreds to tens of thousands of sites call...Chromosomal DNA replication is one of the central biological events occurring inside cells. Due to its large size, the replica-tion of genomic DNA in eukaryotes initiates at hundreds to tens of thousands of sites called DNA origins so that the replication could be completed in a limited time. Further, eukaryotic DNA replication is sophisticatedly regulated, and this regulation guarantees that each origin fires once per S phase and each segment of DNA gets duplication also once per cell cycle. The first step of replication initiation is the assembly of pre-replication complex （pre-RC）. Since 1973, four proteins, Cdc6/Cdcl8, MCM, ORC and Cdtl, have been extensively studied and proved to be pre-RC components. Recently, a novel pre-RC compo- nent called Sapl/Girdin was identified. Sapl/Girdin is required for loading Cdcl8/Cdc6 to origins for pre-RC assembly in the fission yeast and human cells, respectively. At the transition of G1 to S phase, pre-RC is activated by the two kinases, cy- clin-dependent kinase （CDK） and Dbf4-dependent kinase （DDK）, and subsequently, RPA, primase-polct, PCNA, topoisomer-ase, Cdc45, polδ and pole are recruited to DNA origins for creating two bi-directional replication forks and initiating DNA replication. As replication forks move along chromatin DNA, they frequently stall due to the presence of a great number of replication barriers on chromatin DNA, such as secondary DNA structures, protein/DNA complexes, DNA lesions, gene tran-scription. Stalled forks must require checkpoint regulation for their stabilization. Otherwise, stalled forks will collapse, which results in incomplete DNA replication and genomic instability. This short review gives a concise introduction regarding the current understanding of replication initiation and replication fork stabilization.展开更多
文摘AIM:To determine,by counting micronucleus (MN) frequencies,whether chromosomal or DNA damage have an effect on the pathogenesis of early colorectal adenocarcinoma (CRC). METHODS:We analyzed MN frequencies in 21 patients with CRC,24 patients with colon polyps [10 neoplastic polyps (NP) and 14 non-neoplastic polyps (NNP)] and 20 normal controls. RESULTS:MN frequency was significantly increased in CRC patients and in NP patients compared with controls (3.72 ± 1.34,3.58 ± 1.21 vs 1.97 ± 0.81,P < 0.001). However,there was no difference in the MN frequency between CRC patients and NP patients (P > 0.05). Similarly,there was no difference in the MN frequency between NNP patients (2.06 ± 0.85) and controls (P > 0.05). CONCLUSION:Our results suggest increased chromosome/DNA instabilities may be associated with the pathogenesis of early CRC.
文摘Unstable repeats are associated with various types of cancer and have been implicated in more than 40 neurode-generative disorders. Trinucleotide repeats are located in non-coding and coding regions of the genome. Studies of bacteria, yeast, mice and man have helped to unravel some features of the mechanism of trinucleotide expansion. Looped DNA structures comprising trinucleotide repeats are processed during replication and/or repair to generate deletions or expansions. Most in vivo data are consistent with a model in which expansion and deletion occur by different mechanisms. In mammals, microsatellite instability is complex and appears to be influenced by genetic, epigenetic and developmental factors.
基金Supported by the National-Natural Science Foundation of China,No.30070043
文摘AIM：To study the nuclear microsatellite instability (nMSI) at BAT26 and mitochondral microsalellite instability (mtMSI) in the occurrence and development of hepatocellular carcinoma and the relationship between nMSI and mtMSI.METHODS: nMSI was observed with PCR and mtMSI with PCR-SSCP in 52 cases of hepatocellular carcinoma.RESULTS:mtMSI was detected in 11 out of the 52 cases of hepatocellular carcinoma (21.2%). Among the 11 cases of hepatocellular carcinoma with mtMSI, 7 occured in one locus and 4 in 2 loci. The frequency of mtMSI in the 52 cases of hepatocellular carcinoma showed no correlation to sex, age,infection of hepatitis B, liver cirrhosis as well as positive AFP of the patients (P>0.05). In addition, nMSI was detected in 3 out of 52 cases of hepatocellular carcinoma (5.8%) and there was no correlation of the incidence of mtMSI to that of nMSI (P>0.05).CONCLUSION:mtMSI may be involved in the coccurrence and development of hepatocellular carcinoma and it is independent of nMSI.
文摘The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of （E）-13-ocimene. Myrrh was extracted with hexane to avoid inducing changes in the constituents and odor. The main constituent, （E）-L3-ocimene （group A; low boiling point）, and the other constituents （group B; high boiling point） of the hexane extract were separated by bulb-to-bulb distillation. The constituents of groups A and B were analyzed over time by nuclear magnetic resonance analysis and the odors were evaluated. Myrrh＇s odor depended on both the amount of thermally unstable （E）-[3-ocimene, which contributed to the fresh odor, and the constituents of group B （thermally stable）, which contributed to the myrrh-like odor. Six compounds （c^-santalene, （Z）-a-bisabolene, c^-bergamotene, （E）-ct-santalal, c^-photosantalol and campherenol） were isolated from group B. No individual group B component had a myrrh-like odor, although the combined odor of group B was myrrh like. The authors demonstrated that the aroma profile of myrrh depends on the thermal instability of （E）-^-ocimene and a combination of six thermally stable terpenes with similar molecular structures.
文摘Chromosomal DNA replication is one of the central biological events occurring inside cells. Due to its large size, the replica-tion of genomic DNA in eukaryotes initiates at hundreds to tens of thousands of sites called DNA origins so that the replication could be completed in a limited time. Further, eukaryotic DNA replication is sophisticatedly regulated, and this regulation guarantees that each origin fires once per S phase and each segment of DNA gets duplication also once per cell cycle. The first step of replication initiation is the assembly of pre-replication complex （pre-RC）. Since 1973, four proteins, Cdc6/Cdcl8, MCM, ORC and Cdtl, have been extensively studied and proved to be pre-RC components. Recently, a novel pre-RC compo- nent called Sapl/Girdin was identified. Sapl/Girdin is required for loading Cdcl8/Cdc6 to origins for pre-RC assembly in the fission yeast and human cells, respectively. At the transition of G1 to S phase, pre-RC is activated by the two kinases, cy- clin-dependent kinase （CDK） and Dbf4-dependent kinase （DDK）, and subsequently, RPA, primase-polct, PCNA, topoisomer-ase, Cdc45, polδ and pole are recruited to DNA origins for creating two bi-directional replication forks and initiating DNA replication. As replication forks move along chromatin DNA, they frequently stall due to the presence of a great number of replication barriers on chromatin DNA, such as secondary DNA structures, protein/DNA complexes, DNA lesions, gene tran-scription. Stalled forks must require checkpoint regulation for their stabilization. Otherwise, stalled forks will collapse, which results in incomplete DNA replication and genomic instability. This short review gives a concise introduction regarding the current understanding of replication initiation and replication fork stabilization.
