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1.
Front Neurol ; 13: 923669, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36212637

RESUMO

Background: Tai Chi Chuan (TCC) is a physical activity modality that originated in China and is now widely popular around the world. Although there are a series of articles reporting that TCC can improve balance and other functional symptoms in a variety of populations, including the elderly, patients with stroke, and patients with Parkinson's disease, its efficiency has not been scientifically and methodically evaluated in subjects with functional ankle instability (FAI). Moreover, there is no literature directly comparing TCC and conventional balance training (CBT) interventions for FAI. The objective of this study is to investigate the comparative effects of TCC intervention and CBT protocols in improving postural balance and subjective instability feelings in patients with FAI. Methods: This study will be a single-center, parallel group, randomized controlled trial. Sixty-eight patients with FAI will be included and randomly assigned in a 1:1 ratio to either an intervention group (n =34) or a control group (n = 34). The participants in the intervention group will complete 12 weeks of TCC intervention (40 min/time, 3 times/week for 12 weeks) on the basis of health education treatment. The control group will receive health education and 36 CBT sessions during a 12-week period. Outcome measures include postural stability and self-reported feelings of instability at baseline, after the end of the intervention, and 3-month follow-up. The postural stability assessment of patients with FAI will be detected by performing static and dynamic postural tests, which will be carried out through a specific balance platform (TecnoBody ProKin). Self-reported feelings of instability will be assessed by Cumberland Ankle Instability Tool (CAIT), American Orthopedics Foot and Ankle Society's Ankle-Hindfoot Evaluation Scale (AOFAS-AHES), and the MOS item Short Form Health Survey (SF-36). Discussion: This trial will demonstrate whether a 12-week TCC intervention positively affects postural stability and self-reported outcomes in patients with FAI. At the same time, the superiority of its clinical efficacy will also be compared with that of CBT. This study may also help to redefine the value of traditional Chinese exercises in the treatment of chronic ankle instability. Clinical trial registration: Chinese Clinical Trial Registry: ChiCTR2100041790. Registration date: 22 March 2021. http://www.chictr.org.cn/edit.aspx?pid=119501&htm=4.

2.
J Clin Transl Hepatol ; 10(5): 901-912, 2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36304495

RESUMO

Background and Aims: Generally acceptable prognostic models for hepatocellular carcinoma (HCC) are not available. This study aimed to establish a prognostic model for HCC by identifying immune-related differentially expressed genes (IR-DEGs) and to investigate the potential role of NR6A1 in the progression of HCC. Methods: Bioinformatics analysis using The Cancer Genome Atlas and ImmPort databases was used to identify IR-DEGs. Lasso Cox regression and multivariate Cox regression analysis were used to establish a prognostic model of HCC. Kaplan-Meier analysis and the receiver operating characteristic (ROC) curves were used to evaluate the performance of the prognostic model, which was further verified in the International Cancer Genome Consortium (ICGC) database. Gene set enrichment analysis was used to explore the potential pathways of NR6A1. Cell counting kit 8, colony formation, wound healing, and Transwell migration assays using Huh7 cells, and tumor formation models in nude mice were conducted. Results: A prognostic model established based on ten identified IR-DEGs including HSPA4, FABP6, MAPT, NDRG1, APLN, IL17D, LHB, SPP1, GLP1R, and NR6A1, effectively predicted the prognosis of HCC patients, was confirmed by the ROC curves and verified in ICGC database. NR6A1 expression was significantly up-regulated in HCC patients, and NR6A1 was significantly associated with a low survival rate. Gene set enrichment analysis showed the enrichment of cell cycle, mTOR, WNT, and ERBB signaling pathways in patients with high NR6A1 expression. NR6A1 promoted cell proliferation, invasiveness, migration, and malignant tumor formation and growth in vitro and in vivo. Conclusions: An effective prognostic model for HCC, based on a novel signature of 10 immune-related genes, was established. NR6A1 was up-regulated in HCC and was associated with a poor prognosis of HCC. NR6A1 promoted cell proliferation, migration, and growth of HCC, most likely through the cell cycle, mTOR, WNT, and ERBB signaling pathways.

3.
J Sports Med Phys Fitness ; 62(12): 1707-1715, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35333029

RESUMO

INTRODUCTION: Chronic ankle instability (CAI), which is characterized by deficient postural control, is associated with functional limitations and diminished self-reported quality of life. Recent studies have suggested that balance training can improve postural control, but high-quality evidence-based research to confirm the effect of balance training on dynamic postural stability in CAI patients is lacking. The purpose of this study was to synthesize current evidence regarding the effect of balance training on dynamic postural stability in CAI patients. EVIDENCE ACQUISITION: PubMed, Embase, Web of Science and Cochrane Library databases were searched for clinical trials that evaluated the effect of balance training on posture and balance in CAI patients from their inception to 15 July 2021. All statistical analyses were performed in RevMan 5.4. The risk of bias was assessed by the Cochrane Collaboration's risk of bias tool, and studies that reported statistically comparable outcomes were analyzed in meta-analyses using random effects models. Heterogeneity was assessed using the I2 statistic index. EVIDENCE SYNTHESIS: A total of 12 RCTs included in this meta-analysis and revealed that balance training was effective for improving the dynamic posture stability of CAI patients (SMD=0:90; 95% CI: 0.54 to 1.26; P<0:00001, I2=71%; Star Excursion Balance Test). Subgroup analysis (balance training vs. other training) revealed a small negative effect size, but this was not statistically significant (SMD=-0.12, 95% CI=-0.53 to 0.29, P=0.56, I2=9%). Another subgroup analysis (balance training vs. no training) revealed that balance training was more likely to have greater improvement on the dynamic posture stability of CAI patients (SMD=0.94, 95% CI: 0.71 to 1.17; P<0.00001, I2=0%). CONCLUSIONS: Balance training yielded a statistically significant and clinically meaningful improvement in dynamic postural stability in CAI patients. Limited evidence indicates that balance training was more effective than other training methods.


Assuntos
Articulação do Tornozelo , Instabilidade Articular , Humanos , Tornozelo , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Equilíbrio Postural , Doença Crônica
4.
J Clin Transl Hepatol ; 3(4): 265-70, 2015 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-26807382

RESUMO

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of liver dysfunction worldwide, and its prevalence is highly associated with genetic susceptibility. The transmembrane 6 superfamily member 2 (TM6SF2) E167K variant represents a general genetic determinant of hepatic triglyceride content and lobular inflammation, and its presence appears to be directly involved in the pathogenesis and development of NAFLD. Although this variant appears to be a novel powerful modifier in the development of NAFLD, whether it is associated with an increased risk of NAFLD-related liver fibrosis and hepatocellular carcinoma (HCC) remains to be determined. The aim of this review is to describe the functions of the TM6SF2 E167K variant and its association with NAFLD, with particular emphasis on the underlying mechanisms of its role in the development and progression of NAFLD. Additionally, the links between the TM6SF2 E167K variant and NAFLD-related liver fibrosis and HCC will be discussed.

5.
PLoS One ; 9(9): e108132, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25250770

RESUMO

AIMS: To compare the different serum peptidome patterns between twins with and without non-alcoholic fatty liver disease (NAFLD) in order to help understand the pathogenesis of NAFLD and to identify potential diagnostic and therapeutic targets. METHODS: The peptidomics patterns of 63 cases with NAFLD were compared with their twin healthy controls in Qingdao, China. Peptides between 800 Da and 3,500 Da were captured and concentrated using C18 reversed-phase columns, followed by MALDI-TOF mass spectrometry. The sequences of peptides associated with NAFLD were further identified by MALDI-TOF-TOF. Further validation studies were conducted. One hundred additional serum samples were detected by commercially available ELISA kits to calculate the concentrations of complement C3f and fibrinopeptide A, respectively. The differences of these two peptides in the NAFLD and control groups were compared using SPSS 17.0, respectively. RESULTS: Compared with healthy controls, eleven peaks (861.1, 877.07, 904.5, 1206.57, 1350.64, 1518.7, 1690.9, 1777.94, 2931.29, 3190.4, 3261.4) were up-regulated and 7 peaks (942.44, 1020.47, 1060.06, 1211.7, 1263.63, 1449.76, 2768.3) were down-regulated in the NAFLD group. Two peptides derived from complement C3f and fibrinopeptide A, respectively, had the highest ROC values indistinguishing NAFLD cases from their normal controls. In the validation group, the concentrations of complement C3f and fibrinopeptide A (1466.929 ± 78.306 pg/ml, 4.189 ± 0.326 ng/ml, respevtively) in NAFLD group was higher than in control group (complement C3f 1159.357 ± 99.624 pg/ml, FPA 3.039 ± 0.483 ng/ml; P<0.05). CONCLUSIONS: In this study, we established apeptidomics pattern that could help distinguish NAFLD patients from their twin controls. The differently-regulated peptides identified in our study may be potential diagnostic markers or therapeutic targets for NAFLD.


Assuntos
Biomarcadores/sangue , Complemento C3b/análise , Fibrinopeptídeo A/análise , Hepatopatia Gordurosa não Alcoólica/sangue , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Adulto , Biomarcadores/análise , China/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Gêmeos
6.
World J Gastroenterol ; 20(13): 3655-62, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24707151

RESUMO

AIM: To investigate the association between two polymorphisms of apolipoprotein C3 (APOC3) and risk of nonalcoholic fatty liver disease (NAFLD) in a Chinese Han population. METHODS: Genotypes for rs2854116 and rs2854117 in APOC3 and the known rs738409 in patatin-like phospholipase domain-containing protein 3 (PNPLA3) in 390 patients with NAFLD and 409 control subjects were determined by sequencing and polymerase chain reaction analysis. Serum lipid profiles were determined using biochemical methods, and an index of insulin resistance (IR, HOMA-IR), serum APOC3 concentrations and total antioxidant status (TAS) were also assessed. RESULTS: No significant differences in genotype and allele frequencies of rs2854116 and rs2854117 were found between the NAFLD population and the controls (P > 0.05). The OR for the association between -455C and -482T allele carriers and the risk of NAFLD were 1.06 (95%CI: 0.72-1.57, P > 0.05) and 1.00 (95%CI: 0.68-1.48, P > 0.05), respectively. The variant carriers did not have a significantly increased risk of NAFLD or elevated clinical and biochemical parameters such as APOC3 concentrations, IR (1.42 ± 0.43 vs 1.48 ± 0.52, P > 0.05), liver enzymes and TAS (13.94 ± 2.01 vs 14.38 ± 1.92, P > 0.05) compared with the controls. Moreover, the results were similar when testing was carried out independent of the genetic variation in PNPLA3. CONCLUSION: The two polymorphisms of the APOC3 gene are not associated with a risk of NAFLD, or with lipid profiles, IR and oxidative stress in the Chinese Han population.


Assuntos
Apolipoproteína C-III/genética , Lipase/genética , Proteínas de Membrana/genética , Hepatopatia Gordurosa não Alcoólica/genética , Polimorfismo Genético , Adulto , Idoso , Alelos , Antioxidantes/metabolismo , Estudos de Casos e Controles , China/epidemiologia , Feminino , Frequência do Gene , Genótipo , Humanos , Resistência à Insulina , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Razão de Chances , Reação em Cadeia da Polimerase
7.
Zhonghua Gan Zang Bing Za Zhi ; 21(8): 619-23, 2013 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-24119744

RESUMO

OBJECTIVE: To study the relationship between the patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene and hereditary susceptibility to non-alcoholic fatty liver disease (NAFLD) by detecting single nucleotide polymorphisms (SNPs). METHODS: Peripheral blood DNA from 315 patients diagnosed with NAFLD (including the spectrum of simple steatosis (SS) and non-alcoholic steatosis (NASH)) and 336 control subjects was used to determine the PNPLA3 genotype by polymerase chain reaction (PCR) and direct sequencing. The relationship of SNPs and NAFLD-related markers of liver function were assessed by correlation analysis. RESULTS: The SNP rs738409 was identified in more of the NAFLD patients (allele variant frequencies: NAFLD, 65.40%; NASH: 71.87%; SS, 56.47%) than in the controls (33.18%). Case-control analysis revealed that carriers of the 148GG genotype were at 3.81-fold (95% CI: 3.03 ~ 4.79) higher risk of developing NAFLD and at 1.97-fold (95% CI: 1.41 ~ 2.75) higher risk of progressing from SS to NASH, compared with non-carriers. rs738409 was also found to be associated with serum levels of alanine aminotransferase (ALT) and y-glutamyltransferase (y-GT) (both P less than 0.05). Carriers of the 148GG genotype had significantly higher body mass index, ALT, and fasting insulin than carriers of the 148CC genotype (all P less than 0.05), and significantly higher level of serum HDL than carriers of either the 148CC genotype or the 148GC genotype (both P less than 0.05). CONCLUSION: Polymorphisms in the PNPLA3 gene may play an important role in mediating susceptibility to developing NAFLD in the Chinese population. The rs738409 polymorphism, in particular, is related to development and progression of NAFLD and may play a role in the contribution of PNPLA3 to NAFLD pathogenesis.


Assuntos
Fígado Gorduroso/genética , Predisposição Genética para Doença , Lipase/genética , Proteínas de Membrana/genética , Polimorfismo de Nucleotídeo Único , Adolescente , Adulto , Idoso , Alelos , Estudos de Casos e Controles , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica , Adulto Jovem
9.
Proteins ; 81(3): 406-14, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23042597

RESUMO

A missense mutation I148M in PNPLA3 (patatin-like phospholipase domain-containing 3 protein) is significantly correlated with nonalcoholic fatty liver disease (NAFLD). To glean insights into mutation's effect on enzymatic activity, we performed molecular dynamics simulation and flexible docking studies. Our data show that the size of the substrate-access entry site is significantly reduced in mutants, which limits the access of palmitic acid to the catalytic dyad. Besides, the binding free energy calculations suggest low affinity for substrate to mutant enzyme. The substrate-bound system simulations reveal that the spatial arrangement of palmitic acid is distinct in wild-type from that in mutant. The substrate recognition specificity is lost due to the loop where the I148M mutation was located. Our results provide strong evidence for the mechanism by which I148M affects the enzyme activity and suggest that mediating the dynamics may offer a potential avenue for NAFLD.


Assuntos
Domínio Catalítico , Lipase/química , Proteínas de Membrana/química , Simulação de Dinâmica Molecular , Polimorfismo Genético , Biologia Computacional/métodos , Ativação Enzimática , Estabilidade Enzimática , Humanos , Isoleucina/química , Isoleucina/genética , Lipase/genética , Proteínas de Membrana/genética , Complexos Multiproteicos/química , Mutação de Sentido Incorreto , Ácido Palmítico/química , Ligação Proteica , Estrutura Secundária de Proteína , Relação Estrutura-Atividade , Especificidade por Substrato
10.
World J Hepatol ; 4(7): 224-30, 2012 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-22855698

RESUMO

AIM: To evaluate the effect of a 6 and 12 mo lifestyle modification intervention in nonalcoholic fatty liver diseases (NAFLD) in Chengyang District of Qingdao. METHODS: Participants with NAFLD who had resided in Chengyang District for more than 5 years were enrolled in this study. After the 6 and 12 mo lifestyle modification intervention based on physical activity, nutrition and behavior therapy, parameters such as body weight, body mass index (BMI), waist circumference, serum alanine aminotransferase (ALT), aspartate aminotransferase values, serum cholesterol, triglycerides, fasting glucose, fasting insulin and visceral fat area (VFA), the liver-spleen ratio and the homeostasis model assessment of insulin resistance (HOMA-IR) were evaluated and compared between participants with and without the intervention. RESULTS: Seven hundred and twenty-four participants were assigned to the lifestyle intervention group (LS) and 363 participants were assigned to the control group (CON). After the intervention, body weights in the LS group were significantly decreased compared to those in the CON group at 6 mo (11.59% ± 4.7% vs 0.4% ± 0.2%, P = 0.001) and at 12 mo (12.73% ± 5.6% vs 0.9% ± 0.3%, P = 0.001). Compared with the CON group, BMI was more decreased in the LS group after 6 and 12 mo (P = 0.043 and P = 0.032). Waist circumference was more reduced in the LS group than in CON (P = 0.031 and P = 0.017). After the 6 and 12 mo intervention, ALT decreased significantly in the LS group (P = 0.003 and P = 0.002). After 6 and 12 mo, the metabolic syndrome rate had decreased more in the LS group compared with the CON group (P = 0.026 and P = 0.017). After 12 mo, the HOMA-IR score decreased more obviously in the LS group (P = 0.041); this result also appeared in the VFA after 12 mo in the LS group (P = 0.035). CONCLUSION: Lifestyle intervention was effective in improving NAFLD in both 6 and 12 mo interventions. This intervention offered a practical approach for treating a large number of NAFLD patients in the Chengyang District of Qingdao.

11.
World J Gastroenterol ; 17(17): 2248-54, 2011 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-21633537

RESUMO

AIM: To evaluate the association of human leukocyte antigen (HLA)-DQB1 alleles with hepatocellular carcinoma (HCC) through meta-analysis of published data. METHODS: Case-control studies on HLA-DQB1 allele association with HCC published up to January 2010 were included in the analyses. The odds ratios (ORs) of HLA-DQB1 allele distributions in HCC patients were analyzed and compared with healthy controls. The meta-analysis software REVMAN 5.0 was applied for investigating heterogeneity among individual studies and for summarizing all the studies. A meta-analysis was performed using fixed-effect or random-effect methods, depending on the absence or presence of significant heterogeneity. Seven case-control studies containing 398 cases and 594 controls were included in the final analysis. RESULTS: Among the five family alleles, two (DQB1*02 and DQB1*03) were found to be significantly associated with the risk of HCC. The combined OR for the association of DQB1*02 and DQB1*03 allele with the risk for HCC was 1.78 (95% CI: 1.05-3.03, P = 0.03) and 0.65 (95% CI: 0.48-0.89, P = 0.007), respectively. Among the 13 specific alleles, two (DQB1*0502 and DQB1*0602) were significantly associated with risk of HCC. The combined OR for the association of DQB1*0502 and DQB1*0602 allele with the risk for HCC was 1.82 (95% CI: 1.14-2.92, P = 0.01) and 0.58 (95% CI: 0.36-0.95, P = 0.03), respectively. No significant association was established for other HLA-DQB1 family alleles and specific alleles. CONCLUSION: Our results support the hypothesis that specific HLA-DQB1 allele families and alleles might influence the susceptibility or resistance to HCC, although it needs further investigations.


Assuntos
Alelos , Carcinoma Hepatocelular/genética , Antígenos HLA-DQ/genética , Neoplasias Hepáticas/genética , Predisposição Genética para Doença , Cadeias beta de HLA-DQ , Humanos , Risco
13.
Hepatology ; 53(3): 726-36, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21319189

RESUMO

UNLABELLED: The aspartate aminotransferase-to-platelet ratio index (APRI), a tool with limited expense and widespread availability, is a promising noninvasive alternative to liver biopsy for detecting hepatic fibrosis. The objective of this study was to update the 2007 meta-analysis to systematically assess the accuracy of APRI in predicting significant fibrosis, severe fibrosis, and cirrhosis stage in hepatitis C virus (HCV) monoinfected and HCV / human immunodeficiency virus (HIV) coinfected individuals. Studies comparing APRI versus biopsy in HCV patients were identified via a thorough literature search. Areas under summary receiver operating characteristic curves (AUROC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were used to examine the APRI accuracy for the diagnosis of significant fibrosis, severe fibrosis, and cirrhosis. Heterogeneity was explored using meta-regression. Twenty-one additional studies were eligible for the update and, in total, 40 studies were included in this review (n = 8,739). The summary AUROC of the APRI for the diagnosis of significant fibrosis, severe fibrosis, and cirrhosis were 0.77, 0.80, and 0.83, respectively. For significant fibrosis, an APRI threshold of 0.7 was 77% sensitive and 72% specific. For severe fibrosis, a threshold of 1.0 was 61% sensitive and 64% specific. For cirrhosis, a threshold of 1.0 was 76% sensitive and 72% specific. Moreover, we found that the APRI was less accurate for the identification of significant fibrosis, severe fibrosis, and cirrhosis in HIV/HCV coinfected patients. CONCLUSION: Our large meta-analysis suggests that APRI can identify hepatitis C-related fibrosis with a moderate degree of accuracy. Application of this index may decrease the need for staging liver biopsy specimens among chronic hepatitis C patients.


Assuntos
Aspartato Aminotransferases/análise , Hepatite C Crônica/patologia , Cirrose Hepática/patologia , Contagem de Plaquetas , Adulto , Biomarcadores/análise , Biópsia , Feminino , Infecções por HIV/complicações , Infecções por HIV/patologia , Hepatite C Crônica/sangue , Hepatite C Crônica/complicações , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Curva ROC , Sensibilidade e Especificidade
14.
BMC Gastroenterol ; 10: 145, 2010 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-21172035

RESUMO

BACKGROUND: HLA-DRB1 allele polymorphisms have been reported to be associated with hepatocellular carcinoma susceptibility, but the results of these previous studies have been inconsistent. The purpose of the present study was to explore whether specific HLA-DRB1 alleles (DRB1*07, DRB1*12, DRB1*15) confer susceptibility to hepatocellular carcinoma. METHODS: Case-control studies on HLA-DRB1 alleles association with HCC were searched up to January 2010 through a systematic review of the literature. The odds ratios (ORs) of HLA-DRB1 allele distributions in patients with hepatocellular carcinoma were analyzed against healthy controls. The meta-analysis software REVMAN 5.0 was applied for investigating heterogeneity among individual studies and for summarizing all the studies. Meta-analysis was performed using fixed-effect or random-effect methods, depending on absence or presence of significant heterogeneity. RESULTS: Eight case-control studies were included in the final analysis. Among the 3 HLA-DRB1 alleles studied, DRB1*07 and DRB1*12 were significantly associated with the risk of HCC in the whole populations (OR = 1.65, 95% CI: 1.08-2.51, P = 0.02 and OR = 1.59, 95% CI: 1.09-2.32, P = 0.02, respectively). No significant association was established for DRB1*15 allele with HCC in the whole populations. Subgroup analysis by ethnicity showed that DRB1*07, DRB1*12 and DRB1*15 alleles significantly increased the risk of hepatocellular carcinoma in Asians (OR = 2.10, 95% CI: 1.06-4.14, P = 0.03; OR = 1.73, 95% CI: 1.17-2.57, P = 0.006 and OR = 2.88, 95%CI: 1.77-4.69, P <0.001, respectively). CONCLUSION: These results support the hypothesis that specific HLA-DRB1 alleles might influence the susceptibility of hepatocellular carcinoma. Large, multi-ethnic confirmatory and well designed studies are needed to determine the host genetic determinants of hepatocellular carcinoma.


Assuntos
Alelos , Carcinoma Hepatocelular/genética , Antígenos HLA-DR/genética , Neoplasias Hepáticas/genética , Carcinoma Hepatocelular/imunologia , Cadeias HLA-DRB1 , Humanos , Neoplasias Hepáticas/imunologia , Polimorfismo Genético
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 26(10): 1829-32, 2006 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-17205731

RESUMO

The adsorption and oxidation of 1-butanol in alkaline media on a platinum electrode were investigated mainly by EQCM and in situ FTIR spectroscopy. The experimental results demonstrate that the electrooxidation of 1-butanol is closely relative to solution acidity. Since no chemically adsorbed species, such as CO, were evidenced by in situ FTIR spectroscopy, the adsorption of 1-butanol or its dissociative products on Pt surface is suggested by EQCM and CV data. Only one current peak of 1-butanol oxidation in PGPS was detected at -0.23 V/SCE, which illustrated the disappearance of the second current peak due to Pt electrode passivation in alkaline media. The final product of 1-butanol oxidation is only butyric acid anion under experimental condition. It may therefore be suggested that the main reaction occurring at the electrode is the oxidation of 1-butanol to butyric acid anion. The EQCM studies provide quantitative results of surface mass variation and have shed light on elucidating 1-butanol oxidation.

16.
J Inorg Biochem ; 99(11): 2240-7, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16199091

RESUMO

DNA-binding properties of novel copper(II) complex [Cu(l-Phe)(TATP)(H(2)O)](+), where L-Phe=L-phenylalaninate and TATP=1,4,8,9-tetra-aza-triphenylene are investigated using electronic absorption spectroscopy, fluorescence spectroscopy, voltammetry and viscosity measurement. It is found that the presence of calf thymus DNA results in a hypochromism and red shift in the electronic absorption, a quenching effect on fluorescence nature of ethidium bromide-DNA system, an enhanced response on voltammograms of [Co(phen)(3)](3+/2+)-DNA system, and an obvious change in viscosity of DNA. From absorption titration, fluorescence analysis and voltammetric measurement, the binding constant of the complex with DNA is calculated. The latter two methods reveal the stronger binding of [Cu(l-Phe)(TATP)(H(2)O)](+) complex to double strand DNA by the moderate intercalation than [Co(phen)(3)](3+). Such a binding induces the cleavage of plasmid pBR322 DNA in the presence of H(2)O(2).


Assuntos
Compostos Aza/metabolismo , Crisenos/metabolismo , Cobre/metabolismo , Dano ao DNA , DNA/metabolismo , Fenilalanina/metabolismo , Compostos Aza/química , Sítios de Ligação , Crisenos/química , Cobre/química , Ligantes , Fenilalanina/química , Espectrometria de Fluorescência , Viscosidade
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