After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds （VOSCs）： methanethiol （MESH）, dimethyl sulfide （DMS）, dime^yl disulfide （DMDS）, d...After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds （VOSCs）： methanethiol （MESH）, dimethyl sulfide （DMS）, dime^yl disulfide （DMDS）, dimethyl trisulfide （DMTS） and dimethyl tetrasulfide （DMTeS）. Even in the untreated control without a methionine addition, methionine and its catabolites （VOSCs, mainly DMDS） were found in considerable amounts that were high enough to account for the water＇s offensive odor. However, blackening only occurred in two methionine-amended treatments. The VOSCs production was observed to precede black color development, and the reaching of a peak value for total VOSCs was often followed by water blackening. The presence of glucose stimulated the degradation of methionine while postponing the occurrence of the black color and inhibiting the production of VOSCs. In addition, DMDS was found to be the most abundant species produced after the addition of methionine alone, and DMTeS appeared to be the most important compound produced after the addition of methionine＋glucose. These results suggest that methionine acted as an important precursor of the VOSCs in lakes suffering from algea-induced black bloom. The existence of glucose may change the transformation pathway of methionine into VOSCs to form larger molecular weight compounds, such as DMTS and DMTeS.展开更多
Nonalcoholic fatty liver disease(NAFLD)is a heterogeneous and complex disease that is imprecisely diagnosed by liver biopsy.NAFLD covers a spectrum that ranges from simple steatosis,nonalcoholic steatohepatitis(NASH)w...Nonalcoholic fatty liver disease(NAFLD)is a heterogeneous and complex disease that is imprecisely diagnosed by liver biopsy.NAFLD covers a spectrum that ranges from simple steatosis,nonalcoholic steatohepatitis(NASH)with varying degrees of fibrosis,to cirrhosis,which is a major risk factor for hepatocellular carcinoma.Lifestyle and eating habit changes during the last century have made NAFLD the most common liver disease linked to obesity,type 2 diabetes mellitus and dyslipidemia,with a global prevalence of 25%.NAFLD arises when the uptake of fatty acids(FA)and triglycerides(TG)from circulation and de novo lipogenesis saturate the rate of FAβ-oxidation and verylow density lipoprotein(VLDL)-TG export.Deranged lipid metabolism is also associated with NAFLD progression from steatosis to NASH,and therefore,alterations in liver and serum lipidomic signatures are good indicators of the disease’s development and progression.This review focuses on the importance of the classification of NAFLD patients into different subtypes,corresponding to the main alteration(s)in the major pathways that regulate FA homeostasis leading,in each case,to the initiation and progression of NASH.This concept also supports the targeted intervention as a key approach to maximize therapeutic efficacy and opens the door to the development of precise NASH treatments.展开更多
AIM To investigate the interference ofmethionine.free parenteral nutrition plus 5-Fu（-MetTPN+5-Fu）in gastric cancer cell kineticsand the side effects of the regimen.METHODS Fifteen patients with advancedgastric canc...AIM To investigate the interference ofmethionine.free parenteral nutrition plus 5-Fu（-MetTPN+5-Fu）in gastric cancer cell kineticsand the side effects of the regimen.METHODS Fifteen patients with advancedgastric cancer were randomly divided into twogroups,7 patients were given preoperatively aseven-day course of standard parenteralnutrition in combination with a five-day courseof chemotherapy（sTPN+5-Fu）,while the other8 patients were given methionine-deprivedparenteral nutrition and 5-Fu（-MetTPN+5-Fu）.Cell cycles of gastric cancer and normal mucosawere studied by flow cytometry（FCM）.Bloodsamples were taken to measure the serumprotein,methionine（Met）and cysteine（Cys）levels,and liver and kidney functions.RESULTS As compared with the resultsobtained before the treatment,the percentage ofG<sub>0</sub>/G<sub>1</sub> tumor cells increased and that of S phasedecreased in the-MetTPN+5-Fu group,while thecontrary was observed in the sTPN+5-Fu group.Except that the ALT,AST and AKP levels wereslightly increased in a few cases receiving-MetTPN+5-Fu,all the other biochemicalparameters were within normal limits.Serum Cys level decreased slightly after the treatmentin both groups.Serum Met level of patientsreceiving sTPN+5-Fu was somewhat higher aftertreatment than that before treatment;however,no significant change occurred in the -MetTPN+5-Fu group,nor operative complications in bothgroups.CONCLUSION -MetTPN+5-Fu exerted asuppressive effect on cancer cell proliferation,probably through a double mechanism ofcreating a state of'Met starvation'adverse tothe tumor cell cycle,and by allowing 5-Fu to killspecifically cells in S phase.Preoperative short-term administration of -MetTPN+5-Fu had littleundesirable effect on host metabolism.展开更多
AIM: To elucidate whether human primary gastric cancer and gastric mucosa epithelial cells in vitro can grow normally in a methionine (Met) depleted environment, i.e. Met-dependence, and whether Met-depleting status c...AIM: To elucidate whether human primary gastric cancer and gastric mucosa epithelial cells in vitro can grow normally in a methionine (Met) depleted environment, i.e. Met-dependence, and whether Met-depleting status can enhance the killing effect of chemotherapy on gastric cancer cells. METHODS: Fresh human gastric cancer and mucosal tissues were managed to form monocellular suspensions, which were then cultured in the Met-free but homocysteine-containing (Met(-)Hcy(+)) medium, with different chemotherapeutic drugs. The proliferation of the cells was examined by cell counter, flow cytometry (FCM) and microcytotoxicity assay (MTT). RESULTS: The growth of human primary gastric cancer cells in Met(-)Hcy(+) was suppressed, manifested by the decrease of total cell counts [1.46 +/- 0.42 (x 10(9).L(-1)) in Met(-)Hcy(+) vs 1.64 +/-0.44(x 10(9).L(-1)) in Met(+)Hcy(-), P【0.01], the decline in the percentage of G(0)G(1) phase cells (0.69 +/- 0.24 in Met(-)Hcy(+) vs 0.80 +/- 0.18 in Met(+)Hcy(-), P【0.01) and the increase of S cells (0.24 +/- 0.20 in Met(-)Hcy(+) vs 0.17 +/- 0.16 in Met(+)Hcy(-), P【0.01); however, gastric mucosal cells grew normally. If Met(-)Hcy(+) medium was used in combination with chemotherapeutic drugs, the number of surviving gastric cancer cells dropped significantly. CONCLUSION: Human primary gastric cancer cells in vitro are Met-dependent; however, gastric mucosal cells have not shown the same characteristics. Met(-)Hcy(+) environment may strengthen the killing effect of chemotherapy on human primary gastric cancer cells.展开更多
基金supported by the National Natural Science Foundation of China (No. 50979102, 40730528,40901252, 20907057)
文摘After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds （VOSCs）： methanethiol （MESH）, dimethyl sulfide （DMS）, dime^yl disulfide （DMDS）, dimethyl trisulfide （DMTS） and dimethyl tetrasulfide （DMTeS）. Even in the untreated control without a methionine addition, methionine and its catabolites （VOSCs, mainly DMDS） were found in considerable amounts that were high enough to account for the water＇s offensive odor. However, blackening only occurred in two methionine-amended treatments. The VOSCs production was observed to precede black color development, and the reaching of a peak value for total VOSCs was often followed by water blackening. The presence of glucose stimulated the degradation of methionine while postponing the occurrence of the black color and inhibiting the production of VOSCs. In addition, DMDS was found to be the most abundant species produced after the addition of methionine alone, and DMTeS appeared to be the most important compound produced after the addition of methionine＋glucose. These results suggest that methionine acted as an important precursor of the VOSCs in lakes suffering from algea-induced black bloom. The existence of glucose may change the transformation pathway of methionine into VOSCs to form larger molecular weight compounds, such as DMTS and DMTeS.
文摘Nonalcoholic fatty liver disease(NAFLD)is a heterogeneous and complex disease that is imprecisely diagnosed by liver biopsy.NAFLD covers a spectrum that ranges from simple steatosis,nonalcoholic steatohepatitis(NASH)with varying degrees of fibrosis,to cirrhosis,which is a major risk factor for hepatocellular carcinoma.Lifestyle and eating habit changes during the last century have made NAFLD the most common liver disease linked to obesity,type 2 diabetes mellitus and dyslipidemia,with a global prevalence of 25%.NAFLD arises when the uptake of fatty acids(FA)and triglycerides(TG)from circulation and de novo lipogenesis saturate the rate of FAβ-oxidation and verylow density lipoprotein(VLDL)-TG export.Deranged lipid metabolism is also associated with NAFLD progression from steatosis to NASH,and therefore,alterations in liver and serum lipidomic signatures are good indicators of the disease’s development and progression.This review focuses on the importance of the classification of NAFLD patients into different subtypes,corresponding to the main alteration(s)in the major pathways that regulate FA homeostasis leading,in each case,to the initiation and progression of NASH.This concept also supports the targeted intervention as a key approach to maximize therapeutic efficacy and opens the door to the development of precise NASH treatments.
基金the National Natural Science Foundation of China,No.39370780
文摘AIM To investigate the interference ofmethionine.free parenteral nutrition plus 5-Fu（-MetTPN+5-Fu）in gastric cancer cell kineticsand the side effects of the regimen.METHODS Fifteen patients with advancedgastric cancer were randomly divided into twogroups,7 patients were given preoperatively aseven-day course of standard parenteralnutrition in combination with a five-day courseof chemotherapy（sTPN+5-Fu）,while the other8 patients were given methionine-deprivedparenteral nutrition and 5-Fu（-MetTPN+5-Fu）.Cell cycles of gastric cancer and normal mucosawere studied by flow cytometry（FCM）.Bloodsamples were taken to measure the serumprotein,methionine（Met）and cysteine（Cys）levels,and liver and kidney functions.RESULTS As compared with the resultsobtained before the treatment,the percentage ofG<sub>0</sub>/G<sub>1</sub> tumor cells increased and that of S phasedecreased in the-MetTPN+5-Fu group,while thecontrary was observed in the sTPN+5-Fu group.Except that the ALT,AST and AKP levels wereslightly increased in a few cases receiving-MetTPN+5-Fu,all the other biochemicalparameters were within normal limits.Serum Cys level decreased slightly after the treatmentin both groups.Serum Met level of patientsreceiving sTPN+5-Fu was somewhat higher aftertreatment than that before treatment;however,no significant change occurred in the -MetTPN+5-Fu group,nor operative complications in bothgroups.CONCLUSION -MetTPN+5-Fu exerted asuppressive effect on cancer cell proliferation,probably through a double mechanism ofcreating a state of'Met starvation'adverse tothe tumor cell cycle,and by allowing 5-Fu to killspecifically cells in S phase.Preoperative short-term administration of -MetTPN+5-Fu had littleundesirable effect on host metabolism.
基金the Science Foundation of Ministry of Health of China,No.96-2-296
文摘AIM: To elucidate whether human primary gastric cancer and gastric mucosa epithelial cells in vitro can grow normally in a methionine (Met) depleted environment, i.e. Met-dependence, and whether Met-depleting status can enhance the killing effect of chemotherapy on gastric cancer cells. METHODS: Fresh human gastric cancer and mucosal tissues were managed to form monocellular suspensions, which were then cultured in the Met-free but homocysteine-containing (Met(-)Hcy(+)) medium, with different chemotherapeutic drugs. The proliferation of the cells was examined by cell counter, flow cytometry (FCM) and microcytotoxicity assay (MTT). RESULTS: The growth of human primary gastric cancer cells in Met(-)Hcy(+) was suppressed, manifested by the decrease of total cell counts [1.46 +/- 0.42 (x 10(9).L(-1)) in Met(-)Hcy(+) vs 1.64 +/-0.44(x 10(9).L(-1)) in Met(+)Hcy(-), P【0.01], the decline in the percentage of G(0)G(1) phase cells (0.69 +/- 0.24 in Met(-)Hcy(+) vs 0.80 +/- 0.18 in Met(+)Hcy(-), P【0.01) and the increase of S cells (0.24 +/- 0.20 in Met(-)Hcy(+) vs 0.17 +/- 0.16 in Met(+)Hcy(-), P【0.01); however, gastric mucosal cells grew normally. If Met(-)Hcy(+) medium was used in combination with chemotherapeutic drugs, the number of surviving gastric cancer cells dropped significantly. CONCLUSION: Human primary gastric cancer cells in vitro are Met-dependent; however, gastric mucosal cells have not shown the same characteristics. Met(-)Hcy(+) environment may strengthen the killing effect of chemotherapy on human primary gastric cancer cells.
