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Biosynthesis of vitamin B₁₂ (VB₁₂) requires the methylation at positions C-2 and C-7 of the precursor uroporphyrinogen Ⅲ (urogen Ⅲ) to precorrin-2 by S-adenosyl-L-methionine uroporphyrinogen Ⅲ methyltransferase (SUMT), which is a potential bottleneck step. Most of SUMTs are inhibited by urogen Ⅲ and by-product S-adenosyl-L-homocysteine (SAH). In order to mine an SUMT that lacks such an inhibitory property to drive greater flux through the VB₁₂ biosynthetic pathway, we cloned two SUMT genes (RCcobA1, RCcobA2) from Rhodobacter capsulatus SB1003 and expressed them in Escherichia coli BL21 (DE3). Thereafter, the two enzymes were purified and their specific activity of 27.3 U/mg, 68.9 U/mg were determined respectively. The latter was 2.4 times higher than PDcobA (27.9 U/mg) from Pseudomonas denitrifican. Additionally, RCcobA2 could tolerate over 70 μmol/L urogen Ⅲ, which has never been reported before. Hence, RCcobA2 can be used as an efficient enzyme to regulate the VB₁₂ metabolic pathway and enhance VB₁₂ production in industrial strains.
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Objective To explore cost effective means for early detection of malignant tumors in individuals undergoing health check-up.Methods This was a retrospective study involving 280,477 participants who had undergone health check-up including essential items from 2012 to 2016 at the Health Assessment and Intervention Research Center of Jiangsu Province.The protocol was composed of four steps.First,essential items were decided and conducted for all health examination participants.Second,cases with a high risk of malignant tumors were collected and additional tests were specified.Third,suspected malignant tumor cases were identified and recommendations for referrals and follow-up were made.Finally,physicians in charge of follow up would urge suspected cases to visit an oncologist,update case files,give regular instructions,and track recall results.Results There were 517 microscopically confirmed cases of malignant tumors,representing a detection rate of 184/100,000(1.84‰)in individuals seeking regular health check-up and of 2,023/100,000 (20.23‰)in those receiving follow ups.The five most prevalent malignant tumors were thyroid cancer (140 cases or 0.499‰),lung cancer(120 cases or 0.428‰),breast cancer(35 cases or 0.374‰),kidney cancer(55 cases or 0.196‰)and prostate cancer (33 cases or 0.177‰).Conclusions Essential examination items in combination with subsequent special tests,specialist referrals and follow ups are a cost effective way for early detection of malignant tumors in people seeking regular health examinations.
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Objective To explore cost effective means for early detection of malignant tumors in individuals undergoing health check-up.Methods This was a retrospective study involving 280,477 participants who had undergone health check-up including essential items from 2012 to 2016 at the Health Assessment and Intervention Research Center of Jiangsu Province.The protocol was composed of four steps.First,essential items were decided and conducted for all health examination participants.Second,cases with a high risk of malignant tumors were collected and additional tests were specified.Third,suspected malignant tumor cases were identified and recommendations for referrals and follow-up were made.Finally,physicians in charge of follow up would urge suspected cases to visit an oncologist,update case files,give regular instructions,and track recall results.Results There were 517 microscopically confirmed cases of malignant tumors,representing a detection rate of 184/100,000(1.84‰)in individuals seeking regular health check-up and of 2,023/100,000 (20.23‰)in those receiving follow ups.The five most prevalent malignant tumors were thyroid cancer (140 cases or 0.499‰),lung cancer(120 cases or 0.428‰),breast cancer(35 cases or 0.374‰),kidney cancer(55 cases or 0.196‰)and prostate cancer (33 cases or 0.177‰).Conclusions Essential examination items in combination with subsequent special tests,specialist referrals and follow ups are a cost effective way for early detection of malignant tumors in people seeking regular health examinations.
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ObjectiveRetrospectively investigate the characteristics of neoplasma of health checkup participants to find ways to improve cancer detection rate.Methods A total of 186 confirmed cancer patients were enrolled in this study.Personal information,including age,gender,andlocation were collected.The contribution of clinical symptoms,physical examination and laboratory test to cancer detection was investigated.ResultsBiopsy confirmed cancers accounted for 0.133％( 186/140 127 ).Lung (0.036％ ),liver ( 0.017％ ),kidney ( 0.014％ ),colorectal ( 0.013％ ) and gastric cancer ( 0.011％ )were the most commonly found neoplasma.Detection rate of liver cancer in male was significantly higher than that in female (x2 =6.181,P＜0.05 ).Asymptomatic cancer was found in 158 adults (84.9％ ).Ultrasound showed a significantly higher sensitivity to liver,kidney and thyroid cancer than tumor biomarkers.The detection of lung cancer was improved with the combination of X ray,tumor marker( TM ),clinical symptom and low-dose chest CT scan.In 2008,the detection rate for digest system carcinoma (0.083％ ) and lung cancer (x2 =8.538,P＜0.05) was significantly increased (x2 =11.792,P＜0.05).ConclusionsHealth check-up plays an important role in early detection of cancer.The combined use of physical examination,chest X ray,ultrasound test,TM and CT may improve the detection of cancer.