PURPOSE: To review the recent developments in the structure and function of Smad proteins. DATA SOURCES: Both Chinese- and English-language literatures were searched using MEDLINE/CD-ROM (1997 - 2000) and the Index of...PURPOSE: To review the recent developments in the structure and function of Smad proteins. DATA SOURCES: Both Chinese- and English-language literatures were searched using MEDLINE/CD-ROM (1997 - 2000) and the Index of Chinese-Language Literature (1997 - 2000). STUDY SELECTION: Data from published articles about TGF-beta signal transduction in recent domestic and foreign literature were selected. DATA EXTRACTION: Data were mainly extracted from 22 articles which are listed in the reference section of this review. RESULTS: Smad proteins mediate signal transduction induced by the TGF-beta superfamily. Based on their structural and functional properties, Smad proteins are divided into three groups. The first group, receptor-regulated Smads (R-Smads), are phosphorylated by activated type I receptors and form heteromeric complexes with the second group of Smads, common mediator Smads (Co-Smads). These Smad complexes translocate into the nucleus to influence gene transcription. Inhibitory Smads (I-Smads) are the third group and these antagonize the activity of R-Smads. In the nucleus, Smads can directly contact Smad-binding elements (SBE) in target gene promoters. Through interaction with different transcription factors, transcriptional co-activators or co-repressors, Smads elicit different effects in various cell types. The aberrance of Smad proteins has been noted in several human disorders such as fibrosis, hypertrophic scarring and cancer. CONCLUSION: The structure of Smads determines their function as transcriptional factors which translocate signals from the cell surface to the nucleus where Smads regulate TGF-beta superfamily-dependent gene expression.展开更多
AIM: To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-L1 adipocytes. METHODS: The model of insulin resistance in 3T3-L1 adipocy...AIM: To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-L1 adipocytes. METHODS: The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol/L) to the culture medium. Berberine treatment was performed at the same time. Glucose uptake rate was determined by the 2-deoxy-[3H]-D-glucose method. The levels of IkB kinase beta (IKKβ) Ser181 phosphorylation, insulin receptor substrate-1(IRS-1) Ser307 phosphorylation, expression of IKKβ, IRS-1, nuclear transcription factor kappaB p65 (NF-κB p65), phosphatidylinositol-3-kinase p85 (PI-3K p85) and glucose transporter 4 (GLUT4) proteins were detected by Western blotting. The distribution of NF-κB p65 proteins inside the adipocytes was observed through confocal laser scanning microscopy (CLSM). RESULTS: After the intervention of palmic acid for 24 h, the insulin-stimulated glucose transport in 3T3-L1 adipocytes was inhibited by 67%. Meanwhile, the expression of IRS-1 and PI-3K p85 protein was reduced, while the levels of IKKβ Ser181 and IRS-1 Ser307 phosphorylation, and nuclear translocation of NF-κB p65 protein were increased. However, the above indexes, which indicated the existence of insulin resistance, were reversed by berberine although the expression of GLUT4, IKKβ and total NF-κB p65 protein were not changed during this study. CONCLUSION: Insulin resistance induced by FFAs in 3T3-L1 adipocytes can be improved by berberine. Berberine reversed free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ.展开更多
OBJECTIVE: To evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers. METHODS: In a randomized, double-blind, placebo-controlled trial, a total of ...OBJECTIVE: To evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers. METHODS: In a randomized, double-blind, placebo-controlled trial, a total of 216 patients with atrophic gastritis were randomly assigned to one of the four groups: (1) folate (FA, 20 mg per day plus vitamin B(12) 1 mg, intramuscularly, per month for one year, then 20 mg two times a week plus 1 mg per three months for the next year); (2) natural beta-carotene (N-betaC, 30 mg per day for first year, then 30 mg two times a week for the next); (3) synthetic beta-carotene (S-betaC, administered as in N-betaC); and (4) placebo. Follow-ups continued from 1994 to 2001. RESULTS: A total of 7 new cases of gastrointestinal cancers were diagnosed with 3 stomach, 1 colon and 1 esophageal cancers occurring in the placebo group; 1 stomach cancer in both of the N-betaC and S-betaC groups, and no cancer occurring in FA group. In terms of GI cancers, there was a significant reduction in the FA group, compared with the placebo group (P = 0.04). A similar trend was observed in both N-betaC and S-betaC groups (P = 0.07 - 0.08). Taken together, the three intervention groups displayed a highly significant decrease in occurrence (P = 0.004, vs placebo), and a lower risk for GI cancers (OR = 0.12; 95% confidence interval, 0.03 - 0.51). For development of gastric cancer, any one of the three active-treated groups did not reach statistically significant reduction. The FA group showed obvious improvement of the gastric mucosal lesions with more patients displaying lesions reversed or stable atrophy and inflammation (P = 0.04), reversed intestinal metaplasia (P = 0.06) at the end of follow-up, and reversed displasia (P = 0.017) at 12 months. Two cases of false jaundice were found in beta-carotene groups with no influence on administration, and no side-effects were reported in FA group. CONCLUSIONS: This trial revealed the interventional effect of folic acid on the development of GI cancers, a similar eff展开更多
AIM:To observe the effect of acupuncture and moxibustion on the expression of IL-1beta and IL-6 mRNA in ulcerative colitis rats.METHODS:The SD rat ulcerative colitis model was created by immunological method associate...AIM:To observe the effect of acupuncture and moxibustion on the expression of IL-1beta and IL-6 mRNA in ulcerative colitis rats.METHODS:The SD rat ulcerative colitis model was created by immunological method associated with local stimulation. Colonic mucosa was prepared from human fresh surgical colonic specimens, homogenized by adding appropriate amount of normal saline and centrifuged at 3000r/min. The supernatant was collected for measurement of protein conentration and then mixed with Freund adjuvant. This antigen fluid was first injected into the plantae of the model group rats, and then into their plantae, dorsa, inguina and abdominal cavities (noFreund adjuvant for the last injection) again on the 10th, 17th, 24th and 31st day. When a certain titer of serum anti colonic antibody was reached, 2% formalin and antigen fluid (no Freund adjuvant) were administered separately by enema. The ulcerative colitis rat model was thus set up. The animals were randomly divided into four groups: model control group (MC, n = 8), electro acupuncture group (EA, n = 8), herbs partition moxibustion group (HPM 8), normal control group (NC,n = 8). HPM: Moxa cones made of refined mugwort floss were placed on the medicinal pad (medicinal pad dispensing: Radix Aconiti praeparata, cortex Cinnamomi, etc) for Qihai (RN 6) and Tianshu (ST 25, bilateral) and ignited. Two moxa cones were used for each acupoint once a day and 14 times in all. EA: Tianshu (bilateral) and Qihai were stimulated by the intermittent pulse with 2Hz frequency, 4mA intensity for 20 minutes once a day and 14 times in all. After treatment, rats of all four groups were killed simultaneously. The spleen was separated and the distal colon was dissected. Total tissue RNA was isolated by the guanidinium thiocyanate phenol chloroform extraction method. RT-PCR technique was used to study the expression of IL-1 beta and IL-6 mRNA.RESULTS:IL-1 beta and IL-6 mRNAs were not detected in the spleen and colonic mucosa of the NC rats, whereas they were significantly expressed in 展开更多
Aims Understanding what drives the variation in species composition and diversity among local communities can provide insights into the mechanisms of community assembly.Because ecological traits are often thought to b...Aims Understanding what drives the variation in species composition and diversity among local communities can provide insights into the mechanisms of community assembly.Because ecological traits are often thought to be phylogenetically conserved,there should be patterns in phylogenetic structure and phylogenetic diversity in local communities along ecological gradients.We investigate potential patterns in angiosperm assemblages along an elevational gradient with a steep ecological gradient in Changbaishan,China.Methods We used 13 angiosperm assemblages in forest plots(32×32 m)distributed along an elevational gradient from 720 to 1900 m above sea level.We used Faith’s phylogenetic diversity metric to quantify the phylogenetic alpha diversity of each forest plot,used the net relatedness index to quantify the degree of phylogenetic relatedness among angiosperm species within each forest plot and used a phylogenetic dissimilarity index to quantify phylogenetic beta diversity among forest plots.We related the measures of phylogenetic structure and phylogenetic diversity to environmental(climatic and edaphic)factors.Important Findings Our study showed that angiosperm assemblages tended to be more phylogenetically clustered at higher elevations in Changbaishan.This finding is consistent with the prediction of the phylogenetic niche conservatism hypothesis,which highlights the role of niche constraints in governing the phylogenetic structure of assemblages.Our study also showed that woody assemblages differ from herbaceous assemblages in several major aspects.First,phylogenetic clustering dominated in woody assemblages,whereas phylogenetic overdispersion dominated in herbaceous assemblages;second,patterns in phylogenetic relatedness along the elevational and temperature gradients of Changbaishan were stronger for woody assemblages than for herbaceous assemblages;third,environmental variables explained much more variations in phylogenetic relatedness,phylogenetic alpha diversity and phylogenetic beta diversity for wood展开更多
INTRODUCTIONLiver fibrosis or cirrhosis is a common progressively pathological lesion of chronic liver diseases in response to various liver-damaging factors. The main mechanisms of fibrotic or cirrhotic initiation an...INTRODUCTIONLiver fibrosis or cirrhosis is a common progressively pathological lesion of chronic liver diseases in response to various liver-damaging factors. The main mechanisms of fibrotic or cirrhotic initiation and progression at the level of cellular and molecular events have been elucidated in the past two decades[1,2].展开更多
Background Type 2 diabetes is a chronic disease characterized by a progressive loss of beta cell functions. However, the evaluation of beta cell functions is either expensive or inconvenient for clinical practice. We ...Background Type 2 diabetes is a chronic disease characterized by a progressive loss of beta cell functions. However, the evaluation of beta cell functions is either expensive or inconvenient for clinical practice. We aimed to elucidate the association between the changes of insulin responsiveness and the fasting plasma glucose （FPG） during the development of diabetes. Methods A total of 1192 Chinese individuals with normal blood glucose or hyperglycemia were enrolled for the analysis. The early insulinogenic index （△I30/△G30）, the area under the curve of insulin （AUC-Ⅰ）, and homeostasis model assessment were applied to evaluate the early phase secretion, total insulin secretion, and insulin resistance respectively. Polynomial regression analysis was performed to estimate the fluctuation of beta cell functions. Results The △I30/△G30 decreased much more rapidly than the AUC-Ⅰ accompanying with the elevation of FPG. At the FPG of 110 mg/dl （a pre-diabetic stage）, the AI30/AG30 lost 50% of its maximum while the AUC-Ⅰ was still at a compensated normal level. The AUC-Ⅰ exhibited abnormal and decreased gradually at the FPG of from 130 mg/dl to higher （overt diabetes）, while the △I30/△G30 almost remained at 25% of its maximum value. When hyperglycemia continuously existed at 〉 180 mg/dl, both the AI30/AG30 and AUC-Ⅰ were totally lost. Conclusion The increased fasting plasma glucose reflects progressive decompensation of beta cell functions, and could be used to guide the strategy of clinical treatments.展开更多
Objective： To observe the influence on IL-1β and IL-2 in rat models with rheumatoid arthritis after moxibustion on Shenshu （BL 23） and Zusanli （ST 36） points, and to discuss the mechanism of moxibustion. Methods...Objective： To observe the influence on IL-1β and IL-2 in rat models with rheumatoid arthritis after moxibustion on Shenshu （BL 23） and Zusanli （ST 36） points, and to discuss the mechanism of moxibustion. Methods： Fifty male Wistar rats were divided randomly into 5 groups, control group, model group, drug group, moxibustion group, and laser group, 10 for each. Four groups except the normal group were built on the model of rheumatoid arthritis. The changes of body weight and plantar circumference were measured and the level of IL-1β, IL-2 in sera were examined by ELISA. Results： Compared with the model group, the weight and plantar circumference of rats in the moxibustion group were improved significantly after treatment （P〈0.01）, and the improvement of plantar circumference also had significant differences compared with the drug group and the laser group （P〈0.05）. The level of IL-1β, IL-2 in sera were down regulated in the moxibustion group and the laser group, which had statistical differences compared with the model group （P〈0.05）, but no statistical differences were found when comparing with the drug group. Conclusion： Moxibustion obviously improves the toe tumefaction of the rats with rheumatoid arthritis, which is better than CO2 laser of 10.6μm. On the aspect of decreasing the amount of IL-1β, IL-2, CO2 laser of 10.6μm is similar with moxibustion.展开更多
The benzene alkylation process for the production of ethylbenzene has undergone significant improvements during recent decades.Various environmentally benign zeolite-catalyzed ethylbenzene processes,including ZSM-5-ze...The benzene alkylation process for the production of ethylbenzene has undergone significant improvements during recent decades.Various environmentally benign zeolite-catalyzed ethylbenzene processes,including ZSM-5-zeolite-based vapor-phase ethylbenzene processes and Y-,β-,and MCM-22-zeolite-based liquid-phase processes,have been developed and commercialized.Pure ethylene,ethanol,and dilute ethylene have been used as ethylation agents.Here,the development and industrial application of alkylation catalysts and benzene ethylation techniques are summarized,and some other promising innovations are discussed.Recent advances in benzene alkylation over hierarchical zeolites with improved access to active sites and molecular transport are also covered.Zeolites with short diffusion lengths are promising candidates as better alkylation catalysts.The key point is how to obtain such materials easily and economically.The structure-activity relationships of commercial zeolites in these processes are discussed.Liquid-phase processes catalyzed by β and MCM-22 are more profitable than vapor-phase processes catalyzed by ZSM-5.展开更多
BACKGROUND:Transforming growth factor-β(TGF-β) plays an important role in the regulation of cell growth and differentiation,angiogenesis,extracellular matrix formation,immunosuppression and cancer development. In th...BACKGROUND:Transforming growth factor-β(TGF-β) plays an important role in the regulation of cell growth and differentiation,angiogenesis,extracellular matrix formation,immunosuppression and cancer development. In this study,we investigated the levels of TGF-β1 and TGF-β1 mRNA expression,their relationship with HBV replication,and their diagnostic value for hepatocellular carcinoma(HCC). METHODS:Total RNAs were extracted from HCC samples and matched non-tumor tissues,and from peripheral blood mononuclear cells in HCC patients.TGF-β1 mRNA was amplified by RT-PCR and confirmed by DNA sequencing. The distribution of TGF-β1 expression was assessed by immunohistochemistry.The clinical characteristics were analyzed between TGF-β1 and HBV replication.The diagnostic value of circulating TGF-β1 and TGF-β1 mRNA levels were investigated in HCC patients. RESULTS:The incidence of hepatic TGF-β1 expression was 83.3%in HCC samples,43.3%in the surrounding tissues, 94.7%in the HBV DNA-positive group,and 63.6%in the HBV DNA-negative group.Liver TGF-β1 expression was associated with the degree of HCC differentiation and the status of HBV replication,but not with the size or number of tumors.Circulating TGF-β1 level and incidence of TGF-β1 mRNA were significantly higher in the HCC groupthan in any group of patients with benign liver disease, with a higher sensitivity of 89.5%and a specificity of 94.0% for HCC diagnosis when circulating TGF-β1 levels were >1.2μg/L.No significant correlation was found between TGF-β1 expression and AFP level or tumor size.Combining TGF-β1 level and serum AFP raised the detection rate to 97.4%. CONCLUSIONS:Abnormal expression of hepatic TGF-β1 is associated with the degree of HCC differentiation and HBV replication.Both circulating TGF-β1 and TGF-β1 mRNA can be used as sensitive biomarkers for the diagnosis and prognosis of HBV-induced HCC.展开更多
Low thermal expansion superalloys have been used for a number of years in a variety of applications, including gas turbine engines. The low thermal expansion characteristics of the most widely used class of materials ...Low thermal expansion superalloys have been used for a number of years in a variety of applications, including gas turbine engines. The low thermal expansion characteristics of the most widely used class of materials are derived from the ferromagnetic characteristics of Ni, Fe, and Co-based austenitic matrices containing little or no Cr.Alloy developments have been aimed at improving the oxidation resistance and stress accelerated grain boundary oxygen (SAGBO) attack.INCONEL alloy 783 is an oxidation resistant, low coefficient of thermal expansion superalloy developed for gas turbine applications. Alloy 783 represents a culmination in the development, of an alloy system with very high alumtnum content that, in addition to forming γ′,causes βaluminide phase precipitation in the austenitic matrix.This type of structure can be processed to resist both SAGBO and general oxidation,while providing low thermal expansion and useful mechanical properties up to 700℃.Key aspects of the alloy's development are presented.展开更多
Mitophagy is an essential intracellular process that eliminates dysfunctional mitochondria and maintains cellular homeostasis. Mitophagy is regulated by the post-translational modification of mitophagy receptors. Fun1...Mitophagy is an essential intracellular process that eliminates dysfunctional mitochondria and maintains cellular homeostasis. Mitophagy is regulated by the post-translational modification of mitophagy receptors. Fun14 domain-containing protein 1 （FUNDC1） was reported to be a new receptor for hypoxia-induced mitophagy in mammalian cells and interact with micro-tubule-associated protein light chain 3 beta （LC3B） through its LC3 interaction region （LIR）. Moreover, the phosphorylation modification of FUNDC1 affects its binding affinity for LC3B and regulates selective mitophagy. However, the structural basis of this regulation mechanism remains unclear. Here, we present the crystal structure of LC3B in complex with a FUNDCI LIR peptide phosphorylated at Ser17 （pS17）, demonstrating the key residues of LC3B for the specific recognition of the phosphorylated or dephosphorylated FUNDC1. Intriguingly, the side chain of LC3B Lys49 shifts remarkably and forms a hydrogen bond and electrostatic interaction with the phosphate group of FUNDC1 pS17. Alternatively, phosphorylated Tyr18 （PY18） and Ser13 （PS13） in FUNDC1 significantly obstruct their interaction with the hydrophobic pocket and Arg10 of LC3B, respectively. Structural observations are further validated by mutation and isothermal titration calorimetry （ITC） assays. Therefore, our structural and biochemical results reveal a working model for thespecific recognition of FUNDCI by LC3B and imply that the reversible phosphorylation modification of mitophagy receptors may be a switch for selective mitophagy.展开更多
AIM To study the molecular mechanisms ofretinoic acid(RA)on proliferation andexpression of cyclin-dependent kinase inhibitors(CKI),i.e.p16,p21 and p27 in cultured rathepatic stellate cells(HSC)stimulated withtransform...AIM To study the molecular mechanisms ofretinoic acid(RA)on proliferation andexpression of cyclin-dependent kinase inhibitors(CKI),i.e.p16,p21 and p27 in cultured rathepatic stellate cells(HSC)stimulated withtransforming growth factor beta 1(TGF-β1).METHODS HSC were isolated from healthy ratlivers and cultured.After stimulated with1 mg/L TGF-β1,subcultured HSC were treatedwith or without 1 nmol/L RA.MTT assay,immunocytochemistry(ICC)for p16,p21,p27and α-smooth muscle actin(α-SMA)protein,insitu hybridization(ISH)for retinoic acidreceptor beta 2(RAR-β2)and p16,p21 and p27mRNA and quantitative image analysis(partially)were performed.RESULTS RA inhibited HSC proliferation(41.50%,P【0.05),decreased the protein levelof α-SMA(55.09%,P【0.05),and induced HSCto express RAR-β2 mRNA.In addition,RAincreased the protein level of p16(218.75%,P【0.05)and induced p21 protein expression;meanwhile,p27 was undetectable by ICC in bothcontrol and RA-treated HSC.However,RA hadno influence on the mRNA levels of p16,p21 orp27 as determined by ISH.CONCLISION Up-regulation of p16 and p21 on post-transcriptional level may contribule, in part to RA inhibition of TGF-β1-initiated rat HSC activation in vitro.展开更多
基金supported by a grant from the National Natural Science Foundation of China(No．G1999054204)； the National Prominent Youth Science Foundation of China(No．39525024)．
文摘PURPOSE: To review the recent developments in the structure and function of Smad proteins. DATA SOURCES: Both Chinese- and English-language literatures were searched using MEDLINE/CD-ROM (1997 - 2000) and the Index of Chinese-Language Literature (1997 - 2000). STUDY SELECTION: Data from published articles about TGF-beta signal transduction in recent domestic and foreign literature were selected. DATA EXTRACTION: Data were mainly extracted from 22 articles which are listed in the reference section of this review. RESULTS: Smad proteins mediate signal transduction induced by the TGF-beta superfamily. Based on their structural and functional properties, Smad proteins are divided into three groups. The first group, receptor-regulated Smads (R-Smads), are phosphorylated by activated type I receptors and form heteromeric complexes with the second group of Smads, common mediator Smads (Co-Smads). These Smad complexes translocate into the nucleus to influence gene transcription. Inhibitory Smads (I-Smads) are the third group and these antagonize the activity of R-Smads. In the nucleus, Smads can directly contact Smad-binding elements (SBE) in target gene promoters. Through interaction with different transcription factors, transcriptional co-activators or co-repressors, Smads elicit different effects in various cell types. The aberrance of Smad proteins has been noted in several human disorders such as fibrosis, hypertrophic scarring and cancer. CONCLUSION: The structure of Smads determines their function as transcriptional factors which translocate signals from the cell surface to the nucleus where Smads regulate TGF-beta superfamily-dependent gene expression.
基金The National Natural Science Foundation of China, No. 30371816
文摘AIM: To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-L1 adipocytes. METHODS: The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol/L) to the culture medium. Berberine treatment was performed at the same time. Glucose uptake rate was determined by the 2-deoxy-[3H]-D-glucose method. The levels of IkB kinase beta (IKKβ) Ser181 phosphorylation, insulin receptor substrate-1(IRS-1) Ser307 phosphorylation, expression of IKKβ, IRS-1, nuclear transcription factor kappaB p65 (NF-κB p65), phosphatidylinositol-3-kinase p85 (PI-3K p85) and glucose transporter 4 (GLUT4) proteins were detected by Western blotting. The distribution of NF-κB p65 proteins inside the adipocytes was observed through confocal laser scanning microscopy (CLSM). RESULTS: After the intervention of palmic acid for 24 h, the insulin-stimulated glucose transport in 3T3-L1 adipocytes was inhibited by 67%. Meanwhile, the expression of IRS-1 and PI-3K p85 protein was reduced, while the levels of IKKβ Ser181 and IRS-1 Ser307 phosphorylation, and nuclear translocation of NF-κB p65 protein were increased. However, the above indexes, which indicated the existence of insulin resistance, were reversed by berberine although the expression of GLUT4, IKKβ and total NF-κB p65 protein were not changed during this study. CONCLUSION: Insulin resistance induced by FFAs in 3T3-L1 adipocytes can be improved by berberine. Berberine reversed free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ.
基金ThisresearchwaspartlysupportedbytheNationalNaturalScienceFoundationofChina (No 39370 332 )
文摘OBJECTIVE: To evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers. METHODS: In a randomized, double-blind, placebo-controlled trial, a total of 216 patients with atrophic gastritis were randomly assigned to one of the four groups: (1) folate (FA, 20 mg per day plus vitamin B(12) 1 mg, intramuscularly, per month for one year, then 20 mg two times a week plus 1 mg per three months for the next year); (2) natural beta-carotene (N-betaC, 30 mg per day for first year, then 30 mg two times a week for the next); (3) synthetic beta-carotene (S-betaC, administered as in N-betaC); and (4) placebo. Follow-ups continued from 1994 to 2001. RESULTS: A total of 7 new cases of gastrointestinal cancers were diagnosed with 3 stomach, 1 colon and 1 esophageal cancers occurring in the placebo group; 1 stomach cancer in both of the N-betaC and S-betaC groups, and no cancer occurring in FA group. In terms of GI cancers, there was a significant reduction in the FA group, compared with the placebo group (P = 0.04). A similar trend was observed in both N-betaC and S-betaC groups (P = 0.07 - 0.08). Taken together, the three intervention groups displayed a highly significant decrease in occurrence (P = 0.004, vs placebo), and a lower risk for GI cancers (OR = 0.12; 95% confidence interval, 0.03 - 0.51). For development of gastric cancer, any one of the three active-treated groups did not reach statistically significant reduction. The FA group showed obvious improvement of the gastric mucosal lesions with more patients displaying lesions reversed or stable atrophy and inflammation (P = 0.04), reversed intestinal metaplasia (P = 0.06) at the end of follow-up, and reversed displasia (P = 0.017) at 12 months. Two cases of false jaundice were found in beta-carotene groups with no influence on administration, and no side-effects were reported in FA group. CONCLUSIONS: This trial revealed the interventional effect of folic acid on the development of GI cancers, a similar eff
基金Supparted by the Ntiona1 Natura1 Science Foundation of China No.39670899.
文摘AIM:To observe the effect of acupuncture and moxibustion on the expression of IL-1beta and IL-6 mRNA in ulcerative colitis rats.METHODS:The SD rat ulcerative colitis model was created by immunological method associated with local stimulation. Colonic mucosa was prepared from human fresh surgical colonic specimens, homogenized by adding appropriate amount of normal saline and centrifuged at 3000r/min. The supernatant was collected for measurement of protein conentration and then mixed with Freund adjuvant. This antigen fluid was first injected into the plantae of the model group rats, and then into their plantae, dorsa, inguina and abdominal cavities (noFreund adjuvant for the last injection) again on the 10th, 17th, 24th and 31st day. When a certain titer of serum anti colonic antibody was reached, 2% formalin and antigen fluid (no Freund adjuvant) were administered separately by enema. The ulcerative colitis rat model was thus set up. The animals were randomly divided into four groups: model control group (MC, n = 8), electro acupuncture group (EA, n = 8), herbs partition moxibustion group (HPM 8), normal control group (NC,n = 8). HPM: Moxa cones made of refined mugwort floss were placed on the medicinal pad (medicinal pad dispensing: Radix Aconiti praeparata, cortex Cinnamomi, etc) for Qihai (RN 6) and Tianshu (ST 25, bilateral) and ignited. Two moxa cones were used for each acupoint once a day and 14 times in all. EA: Tianshu (bilateral) and Qihai were stimulated by the intermittent pulse with 2Hz frequency, 4mA intensity for 20 minutes once a day and 14 times in all. After treatment, rats of all four groups were killed simultaneously. The spleen was separated and the distal colon was dissected. Total tissue RNA was isolated by the guanidinium thiocyanate phenol chloroform extraction method. RT-PCR technique was used to study the expression of IL-1 beta and IL-6 mRNA.RESULTS:IL-1 beta and IL-6 mRNAs were not detected in the spleen and colonic mucosa of the NC rats, whereas they were significantly expressed in
基金China National Scientific and Technical Foundation Project(2012FY112000 to Z.H.)。
文摘Aims Understanding what drives the variation in species composition and diversity among local communities can provide insights into the mechanisms of community assembly.Because ecological traits are often thought to be phylogenetically conserved,there should be patterns in phylogenetic structure and phylogenetic diversity in local communities along ecological gradients.We investigate potential patterns in angiosperm assemblages along an elevational gradient with a steep ecological gradient in Changbaishan,China.Methods We used 13 angiosperm assemblages in forest plots(32×32 m)distributed along an elevational gradient from 720 to 1900 m above sea level.We used Faith’s phylogenetic diversity metric to quantify the phylogenetic alpha diversity of each forest plot,used the net relatedness index to quantify the degree of phylogenetic relatedness among angiosperm species within each forest plot and used a phylogenetic dissimilarity index to quantify phylogenetic beta diversity among forest plots.We related the measures of phylogenetic structure and phylogenetic diversity to environmental(climatic and edaphic)factors.Important Findings Our study showed that angiosperm assemblages tended to be more phylogenetically clustered at higher elevations in Changbaishan.This finding is consistent with the prediction of the phylogenetic niche conservatism hypothesis,which highlights the role of niche constraints in governing the phylogenetic structure of assemblages.Our study also showed that woody assemblages differ from herbaceous assemblages in several major aspects.First,phylogenetic clustering dominated in woody assemblages,whereas phylogenetic overdispersion dominated in herbaceous assemblages;second,patterns in phylogenetic relatedness along the elevational and temperature gradients of Changbaishan were stronger for woody assemblages than for herbaceous assemblages;third,environmental variables explained much more variations in phylogenetic relatedness,phylogenetic alpha diversity and phylogenetic beta diversity for wood
文摘INTRODUCTIONLiver fibrosis or cirrhosis is a common progressively pathological lesion of chronic liver diseases in response to various liver-damaging factors. The main mechanisms of fibrotic or cirrhotic initiation and progression at the level of cellular and molecular events have been elucidated in the past two decades[1,2].
文摘Background Type 2 diabetes is a chronic disease characterized by a progressive loss of beta cell functions. However, the evaluation of beta cell functions is either expensive or inconvenient for clinical practice. We aimed to elucidate the association between the changes of insulin responsiveness and the fasting plasma glucose （FPG） during the development of diabetes. Methods A total of 1192 Chinese individuals with normal blood glucose or hyperglycemia were enrolled for the analysis. The early insulinogenic index （△I30/△G30）, the area under the curve of insulin （AUC-Ⅰ）, and homeostasis model assessment were applied to evaluate the early phase secretion, total insulin secretion, and insulin resistance respectively. Polynomial regression analysis was performed to estimate the fluctuation of beta cell functions. Results The △I30/△G30 decreased much more rapidly than the AUC-Ⅰ accompanying with the elevation of FPG. At the FPG of 110 mg/dl （a pre-diabetic stage）, the AI30/AG30 lost 50% of its maximum while the AUC-Ⅰ was still at a compensated normal level. The AUC-Ⅰ exhibited abnormal and decreased gradually at the FPG of from 130 mg/dl to higher （overt diabetes）, while the △I30/△G30 almost remained at 25% of its maximum value. When hyperglycemia continuously existed at 〉 180 mg/dl, both the AI30/AG30 and AUC-Ⅰ were totally lost. Conclusion The increased fasting plasma glucose reflects progressive decompensation of beta cell functions, and could be used to guide the strategy of clinical treatments.
文摘Objective： To observe the influence on IL-1β and IL-2 in rat models with rheumatoid arthritis after moxibustion on Shenshu （BL 23） and Zusanli （ST 36） points, and to discuss the mechanism of moxibustion. Methods： Fifty male Wistar rats were divided randomly into 5 groups, control group, model group, drug group, moxibustion group, and laser group, 10 for each. Four groups except the normal group were built on the model of rheumatoid arthritis. The changes of body weight and plantar circumference were measured and the level of IL-1β, IL-2 in sera were examined by ELISA. Results： Compared with the model group, the weight and plantar circumference of rats in the moxibustion group were improved significantly after treatment （P〈0.01）, and the improvement of plantar circumference also had significant differences compared with the drug group and the laser group （P〈0.05）. The level of IL-1β, IL-2 in sera were down regulated in the moxibustion group and the laser group, which had statistical differences compared with the model group （P〈0.05）, but no statistical differences were found when comparing with the drug group. Conclusion： Moxibustion obviously improves the toe tumefaction of the rats with rheumatoid arthritis, which is better than CO2 laser of 10.6μm. On the aspect of decreasing the amount of IL-1β, IL-2, CO2 laser of 10.6μm is similar with moxibustion.
文摘The benzene alkylation process for the production of ethylbenzene has undergone significant improvements during recent decades.Various environmentally benign zeolite-catalyzed ethylbenzene processes,including ZSM-5-zeolite-based vapor-phase ethylbenzene processes and Y-,β-,and MCM-22-zeolite-based liquid-phase processes,have been developed and commercialized.Pure ethylene,ethanol,and dilute ethylene have been used as ethylation agents.Here,the development and industrial application of alkylation catalysts and benzene ethylation techniques are summarized,and some other promising innovations are discussed.Recent advances in benzene alkylation over hierarchical zeolites with improved access to active sites and molecular transport are also covered.Zeolites with short diffusion lengths are promising candidates as better alkylation catalysts.The key point is how to obtain such materials easily and economically.The structure-activity relationships of commercial zeolites in these processes are discussed.Liquid-phase processes catalyzed by β and MCM-22 are more profitable than vapor-phase processes catalyzed by ZSM-5.
文摘BACKGROUND:Transforming growth factor-β(TGF-β) plays an important role in the regulation of cell growth and differentiation,angiogenesis,extracellular matrix formation,immunosuppression and cancer development. In this study,we investigated the levels of TGF-β1 and TGF-β1 mRNA expression,their relationship with HBV replication,and their diagnostic value for hepatocellular carcinoma(HCC). METHODS:Total RNAs were extracted from HCC samples and matched non-tumor tissues,and from peripheral blood mononuclear cells in HCC patients.TGF-β1 mRNA was amplified by RT-PCR and confirmed by DNA sequencing. The distribution of TGF-β1 expression was assessed by immunohistochemistry.The clinical characteristics were analyzed between TGF-β1 and HBV replication.The diagnostic value of circulating TGF-β1 and TGF-β1 mRNA levels were investigated in HCC patients. RESULTS:The incidence of hepatic TGF-β1 expression was 83.3%in HCC samples,43.3%in the surrounding tissues, 94.7%in the HBV DNA-positive group,and 63.6%in the HBV DNA-negative group.Liver TGF-β1 expression was associated with the degree of HCC differentiation and the status of HBV replication,but not with the size or number of tumors.Circulating TGF-β1 level and incidence of TGF-β1 mRNA were significantly higher in the HCC groupthan in any group of patients with benign liver disease, with a higher sensitivity of 89.5%and a specificity of 94.0% for HCC diagnosis when circulating TGF-β1 levels were >1.2μg/L.No significant correlation was found between TGF-β1 expression and AFP level or tumor size.Combining TGF-β1 level and serum AFP raised the detection rate to 97.4%. CONCLUSIONS:Abnormal expression of hepatic TGF-β1 is associated with the degree of HCC differentiation and HBV replication.Both circulating TGF-β1 and TGF-β1 mRNA can be used as sensitive biomarkers for the diagnosis and prognosis of HBV-induced HCC.
文摘Low thermal expansion superalloys have been used for a number of years in a variety of applications, including gas turbine engines. The low thermal expansion characteristics of the most widely used class of materials are derived from the ferromagnetic characteristics of Ni, Fe, and Co-based austenitic matrices containing little or no Cr.Alloy developments have been aimed at improving the oxidation resistance and stress accelerated grain boundary oxygen (SAGBO) attack.INCONEL alloy 783 is an oxidation resistant, low coefficient of thermal expansion superalloy developed for gas turbine applications. Alloy 783 represents a culmination in the development, of an alloy system with very high alumtnum content that, in addition to forming γ′,causes βaluminide phase precipitation in the austenitic matrix.This type of structure can be processed to resist both SAGBO and general oxidation,while providing low thermal expansion and useful mechanical properties up to 700℃.Key aspects of the alloy's development are presented.
基金This work was supported by National Natural Science Founda- tion （Grant No. 31400629） the Strategic Priority Research Program of the Chinese Academy of Science （No. XDB08010101）+1 种基金 Ministry Of Science And Technology of China （No. 2016YFA0500700） China Postdoctoral Science Foundation （No. 2015M582009 and 2016T90579） and National Natural Science Foundation （Grant No. 31330018）.
文摘Mitophagy is an essential intracellular process that eliminates dysfunctional mitochondria and maintains cellular homeostasis. Mitophagy is regulated by the post-translational modification of mitophagy receptors. Fun14 domain-containing protein 1 （FUNDC1） was reported to be a new receptor for hypoxia-induced mitophagy in mammalian cells and interact with micro-tubule-associated protein light chain 3 beta （LC3B） through its LC3 interaction region （LIR）. Moreover, the phosphorylation modification of FUNDC1 affects its binding affinity for LC3B and regulates selective mitophagy. However, the structural basis of this regulation mechanism remains unclear. Here, we present the crystal structure of LC3B in complex with a FUNDCI LIR peptide phosphorylated at Ser17 （pS17）, demonstrating the key residues of LC3B for the specific recognition of the phosphorylated or dephosphorylated FUNDC1. Intriguingly, the side chain of LC3B Lys49 shifts remarkably and forms a hydrogen bond and electrostatic interaction with the phosphate group of FUNDC1 pS17. Alternatively, phosphorylated Tyr18 （PY18） and Ser13 （PS13） in FUNDC1 significantly obstruct their interaction with the hydrophobic pocket and Arg10 of LC3B, respectively. Structural observations are further validated by mutation and isothermal titration calorimetry （ITC） assays. Therefore, our structural and biochemical results reveal a working model for thespecific recognition of FUNDCI by LC3B and imply that the reversible phosphorylation modification of mitophagy receptors may be a switch for selective mitophagy.
基金the National Natural Science Foundation of China,No.39670287the Scientific Research Foundation for Doctorate Education,State Education Commission.No.96026530
文摘AIM To study the molecular mechanisms ofretinoic acid(RA)on proliferation andexpression of cyclin-dependent kinase inhibitors(CKI),i.e.p16,p21 and p27 in cultured rathepatic stellate cells(HSC)stimulated withtransforming growth factor beta 1(TGF-β1).METHODS HSC were isolated from healthy ratlivers and cultured.After stimulated with1 mg/L TGF-β1,subcultured HSC were treatedwith or without 1 nmol/L RA.MTT assay,immunocytochemistry(ICC)for p16,p21,p27and α-smooth muscle actin(α-SMA)protein,insitu hybridization(ISH)for retinoic acidreceptor beta 2(RAR-β2)and p16,p21 and p27mRNA and quantitative image analysis(partially)were performed.RESULTS RA inhibited HSC proliferation(41.50%,P【0.05),decreased the protein levelof α-SMA(55.09%,P【0.05),and induced HSCto express RAR-β2 mRNA.In addition,RAincreased the protein level of p16(218.75%,P【0.05)and induced p21 protein expression;meanwhile,p27 was undetectable by ICC in bothcontrol and RA-treated HSC.However,RA hadno influence on the mRNA levels of p16,p21 orp27 as determined by ISH.CONCLISION Up-regulation of p16 and p21 on post-transcriptional level may contribule, in part to RA inhibition of TGF-β1-initiated rat HSC activation in vitro.
