共查询到20条相似文献,搜索用时 15 毫秒
1.
Hua Zhang Jingnan Liu Caroline R. Li Bahram Momen Ronald A. Kohanski Leslie Pick 《Proceedings of the National Academy of Sciences of the United States of America》2009,106(46):19617-19622
Insulin/Insulin-like growth factor signaling regulates homeostasis and growth in mammals, and is implicated in diseases from diabetes to cancer. In Drosophila melanogaster, as in other invertebrates, multiple Insulin-Like Peptides (DILPs) are encoded by a family of related genes. To assess DILPs'' physiological roles, we generated small deficiencies that uncover single or multiple dilps, generating genetic loss-of-function mutations. Deletion of dilps1–5 generated homozygotes that are small, severely growth-delayed, and poorly viable and fertile. These animals display reduced metabolic activity, decreased triglyceride levels and prematurely activate autophagy, indicative of “starvation in the midst of plenty,” a hallmark of Type I diabetes. Furthermore, circulating sugar levels are elevated in Df [dilp1–5] homozygotes during eating and fasting. In contrast, Df[dilp6] or Df[dilp7] animals showed no major metabolic defects. We discuss physiological differences between mammals and insects that may explain the unexpected survival of lean, ‘diabetic’ flies. 相似文献
2.
Ryoichi Fujiwara Nghia Nguyen Shujuan Chen Robert H. Tukey 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(11):5024-5029
High levels of unconjugated bilirubin (UCB) in newborn children is associated with a reduction in hepatic UDP glucuronosyltransferase (UGT) 1A1 activity that can lead to CNS toxicity, brain damage, and even death. Little is known regarding those events that lead to UCB accumulation in brain tissue, and therefore, we sought to duplicate this condition in mice. The human UGT1 locus, encoding all 9-UGT1A genes including UGT1A1, was expressed in Ugt1−/− mice. Because the most common clinical condition associated with jaundice in adults is Gilbert’s syndrome, which is characterized by an allelic polymorphism in the UGT1A1 promoter, hyperbilirubinemia was monitored in humanized UGT1 mice that expressed either the Gilbert’s UGT1A1*28 allele [Tg(UGT1A1*28)Ugt1−/− mice] or the normal UGT1A1*1 allele [Tg(UGT1A1*1)Ugt1−/− mice]. Adult Tg(UGT1A1*28)Ugt1−/− mice expressed elevated levels of total bilirubin (TB) compared with Tg(UGT1A1*1)Ugt1−/− mice, confirming that the promoter polymorphism associated with the UGT1A1*28 allele contributes to hyperbilirubinemia in mice. However, TB accumulated to near toxic levels during neonatal development, a finding that is independent of the Gilbert’s UGT1A1*28 promoter polymorphism. Whereas serum TB levels eventually returned to adult levels, TB clearance in neonatal mice was not associated with hepatic UGT1A1 expression. In ∼10% of the humanized UGT1 mice, peak TB levels culminated in seizures followed by death. UCB deposition in brain tissue and the ensuing seizures were associated with developmental milestones and can be prevented by enhancing regulation of the UGT1A1 gene in neonatal mice. 相似文献
3.
Manzoor A. Malik Priya Srivastava Showkat A. Zargar Balraj Mittal 《Saudi Journal Of Gastroenterology》2014,20(6):371-377
Background/Aim:
Phospholipase C epsilon 1 (PLCE1) plays a crucial role in carcinogenesis and progression of several types of cancers. A single nucleotide polymorphism (SNP, rs2274223) in PLCE1 has been identified as a novel susceptibility locus. The aim of the present study was to investigate the role of three potentially functional SNPs (rs2274223A > G, rs3765524C > T, and rs7922612C > T) of PLCE1 in gastric cancer patients from Kashmir Valley.Patients and Methods:
The study was conducted in 108 GC cases and 195 healthy controls from Kashmir Valley. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism method. Data were statistically analyzed using χ2 test and logistic regression models. A P value of less than 0.05 was regarded as statistically significant.Results:
The frequency of PLCE1 A2274223C3765524T7922612, G2274223C3765524T7922612, and G2274223T3765524C7922612 haplotypes were higher in patients compared with controls, conferred high risk for GC [odds ratio (OR) =6.29; P = 0.001; Pcorr = 0.003], (OR = 3.23; P = 0.011; Pcorr = 0.033), and (OR = 5.14; P = 0.011; Pcorr = 0.033), respectively. Smoking and salted tea are independent risk factors for GC, but we did not find any significant modulation of cancer risk by PLCE1 variants with smoking or excessive consumption of salted tea.Conclusion:
These results suggest that variation in PLCE1 may be associated with GC risk in Kashmir Valley. 相似文献4.
Shao-Qin Chen Zhi-Hua Chen Su-Yong Lin Qi-Bao Dai Leng-Xi Fu Rui-Qing Chen 《World journal of gastroenterology : WJG》2014,20(29):10071-10081
AIM:To examine the effect of aberrant methylation of the KISS1 promoter on the development of colorectal cancer(CRC)and to investigate reversing aberrant methylation of the KISS1 promoter as a potential therapeutic target.METHODS:KISS1 promoter methylation,mRNA expression and protein expression were detected by methylation-specific polymerase chain reaction(PCR),real-time quantitative PCR and Western blotting,respectively,in 126 CRC tissues and 142 normal colorectal tissues.Human CRC cells with KISS1 promoter hypermethylation and poor KISS1 expression were treated in vitro with 5-aza-2’-deoxycytidine(5-Aza-CdR).After treatment,KISS1 promoter methylation,KISS1 mRNA and protein expression and cell migration and invasion were evaluated.RESULTS:Hypermethylation of KISS1 occurred frequently in CRC samples(83.1%,105/126),but was infrequent in normal colorectal tissues(6.34%,9/142).Moreover,KISS1 methylation was associated with tumor differentiation,the depth of invasion,lymph node metastasis and distant metastasis(P<0.001).KISS1methylation was also associated with low KISS1 expression(P<0.001).Furthermore,we observed re-expression of the KISS1 gene and decreased cell migration after 5-Aza-CdR treatment in a CRC cell line.CONCLUSION:These data suggest that KISS1 is down-regulated in cancer tissues via promoter hypermethylation and therefore may represent a candidate target for treating metastatic CRC. 相似文献
5.
Intestine-specific ablation of mouse atonal homolog 1 (Math1) reveals a role in cellular homeostasis 总被引:1,自引:0,他引:1
Shroyer NF Helmrath MA Wang VY Antalffy B Henning SJ Zoghbi HY 《Gastroenterology》2007,132(7):2478-2488
6.
Schnittger S Bacher U Haferlach C Kern W Alpermann T Haferlach T 《Haematologica》2011,96(12):1799-1807
Background
Combined treatment with all-trans-retinoic acid and chemotherapy is extremely efficient in patients with acute promyelocytic leukemia with t(15;17)/PML-RARA, but up to 15% of patients relapse.Design and Methods
To further clarify the prognostic impact of parameters such as FLT3 mutations, we comprehensively characterized the relation between genetic features and outcome in 147 patients (aged 19.7–86.3 years) with acute promyelocytic leukemia.Results
Internal tandem duplications of the FLT3 gene (FLT3-ITD) were detected in 47/147 (32.0%) and tyrosine kinase domain mutations (FLT3-TKD) in 19/147 (12.9%) patients. FLT3-ITD or FLT3-TKD mutation status did not have a significant prognostic impact, whereas FLT3-ITD mutation load, as defined by a mutation/wild-type ratio of less than 0.5 was associated with trends to a better 2-year overall survival rate (86.7% versus 72.7%; P=0.075) and 2-year event-free survival rate (84.5% versus 62.1%, P=0.023) compared to the survival rates of patients with a ratio of 0.5 or more. Besides the t(15;17), an additional chromosomal abnormality was detected in 57 of 147 cases and did not show a significant impact on survival. White blood cell counts of 10×109/L or less versus more than 10×109/L were associated with a better 2-year overall survival rate (88.3% versus 69.4%, respectively; P=0.015), as was male sex (P=0.040). In multivariate analysis, only higher age had a significant adverse impact.Conclusions
Prospective trials should further investigate the clinical impact of the FLT3-ITD/wild-type mutation load aiming to evaluate whether this parameter might be included in risk stratification in patients with acute promyelocytic leukemia. 相似文献7.
8.
William S. Stevenson Craig D. Hyland Jian-Guo Zhang Phillip O. Morgan Tracy A. Willson Anthony Gill Adrienne A. Hilton Elizabeth M. Viney Melanie Bahlo Seth L. Masters Sarah Hennebry Samantha J. Richardson Nicos A. Nicola Donald Metcalf Douglas J. Hilton Andrew W. Roberts Warren S. Alexander 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(38):16625-16630
With the notable exception of humans, uric acid is degraded to (S)-allantoin in a biochemical pathway catalyzed by urate oxidase, 5-hydroxyisourate (HIU) hydrolase, and 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline decarboxylase in most vertebrate species. A point mutation in the gene encoding mouse HIU hydrolase, Urah, that perturbed uric acid metabolism within the liver was discovered during a mutagenesis screen in mice. The predicted substitution of cysteine for tyrosine in a conserved helical region of the mutant-encoded HIU hydrolase resulted in undetectable protein expression. Mice homozygous for this mutation developed elevated platelet counts secondary to excess thrombopoietin production and hepatomegaly. The majority of homozygous mutant mice also developed hepatocellular carcinoma, and tumor development was accelerated by exposure to radiation. The development of hepatomegaly and liver tumors in mice lacking Urah suggests that uric acid metabolites may be toxic and that urate oxidase activity without HIU hydrolase function may affect liver growth and transformation. The absence of HIU hydrolase in humans predicts slowed metabolism of HIU after clinical administration of exogenous urate oxidase in conditions of uric acid-related pathology. The data suggest that prolonged urate oxidase therapy should be combined with careful assessment of toxicity associated with extrahepatic production of uric acid metabolites. 相似文献
9.
Hirsch P Tang R Marzac C Perrot JY Fava F Bernard C Jeziorowska D Marie JP Legrand O 《Haematologica》2012,97(2):241-245
ATP-binding cassette transporter (and specially P-glycoprotein) activity is a well known prognostic factor in acute myeloid leukemia, but when compared to other molecular markers its prognostic value has not been well studied. Here we study relationships between this activity, fms-like tyro-sine kinase 3(FLT3/ITD), nucleophosmin(NPM1), CAAT-enhancer binding protein alpha(CEBPα), and brain and acute leukemia cytoplasmic protein (BAALC), in 111 patients with normal cytogenetics who underwent the same treatment, and evaluate its prognostic impact. Independent factors for survival were age (P=0.0126), ATP-binding cassette transporter activity (P=0.018) and duplications in the fms-like tyrosine kinase 3 (P=0.0273). In the 66 patients without fms-like tyrosine kinase 3 duplication and without nucleophosmin mutation, independent prognostic factors for complete remission achievement and survival were age and ATP-binding cassette transporter activity. In conclusion, ATP-binding cassette transporter activity remains an independent prognostic factor, and could assist treatment decisions in patients with no nucleophosmin mutation and no fms-like tyrosine kinase 3 duplication. 相似文献
10.
La1−xSrxTiO3+δ has attracted much attention as an important perovskite oxide. However, there are rare reports on its optical properties, especially reflectivity. In this paper, its structural and optical properties were studied. The X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and spectrophotometer were used to characterize the sample. The results show that with increasing Sr concentration, the number of TiO6 octahedral layers in each “slab” increases and the crystal structure changes from layered to cubic structure. A proper Sr doping (x = 0.1) can increase the reflectivity, reaching 95% in the near infrared range, which is comparable with metal Al measured in the same condition. This indicates its potential applications as optical protective coatings or anti-radiation materials at high temperatures. 相似文献
11.
BackgroundThe para-Bombay phenotype results from a variety of mutations in the α-(1,2)-fucosyltransferase gene (FUT1). We investigated samples from seven Chinese probands serologically typed as having the para-Bombay phenotype.ResultsThree FUT1 genotypes, h1/h1 (5 individuals), h1/h6 (1 individual) and h3/h2 (1 individual), and three FUT2 genotypes, Se357/Se357 (5 individuals), Se357/Se357, 385 (1 individual) and Se357/Se357, 716 (1 individual) were observed in seven para-Bombay probands. Among 331 donors, only one individual carried the G716A and 880delTT mutations in heterozygosity; this subjects FUT1 and FUT2 genotypes were H/h2 and Se357/Se357, 716, respectively.ConclusionThe review of all para-Bombay probands identified in the Fujian Blood Centre showed that h1 and h2 are the predominant non-functional FUT1 alleles in Fujian para-Bombay individuals. Our data confirm the hypothesis that the h2 allele is linked to Se357, 716, and the concurrence of unique FUT1 and FUT2 mutations is geographically specific. 相似文献
12.
Carlos Eduardo de Castro Alves Sabrina Araújo de Melo Jean de Melo Silva Leonardo Calheiros de Oliveira Valdinete Alves do Nascimento Joo Hugo Abdalla Santos Felipe Gomes Naveca Gemilson Soares Pontes 《Viruses》2022,14(5)
The systemic inflammatory response elicited by acute Zika virus (ZIKV) infection during pregnancy plays a key role in the clinical outcomes in mothers and congenitally infected offspring. The present study aimed to evaluate the serum levels of GDF-3 and inflammasome-related markers in pregnant women during acute ZIKV infection. Serum samples from pregnant (n = 18) and non-pregnant (n = 22) women with acute ZIKV infection were assessed for NLRP3, IL-1β, IL-18, and GDF3 markers through an enzyme-linked immunosorbent assay. ZIKV-negative pregnant (n = 18) and non-pregnant women (n = 15) were used as control groups. All serum markers were highly elevated in the ZIKV-infected groups in comparison with control groups (p < 0.0001). Among the ZIKV-infected groups, the serum markers were significantly augmented in the pregnant women in comparison with non-pregnant women (NLRP3 p < 0.001; IL-1β, IL-18, and GDF3 p < 0.0001). The IL-18 marker was found at significantly higher levels (p < 0.05) in the third trimester of pregnancy. Bivariate and multivariate analyses showed a strong positive correlation between GDF3 and NLRP3 markers among ZIKV-infected pregnant women (r = 0.91, p < 0.0001). The findings indicated that acute ZIKV infection during pregnancy induces the overexpression of GDF-3 and inflammasome-related markers, which may contribute to congenital disorders and harmful pregnancy outcomes. 相似文献
13.
Shaobing O. Zhang Andrew C. Box Ningyi Xu Johan Le Men Jingyi Yu Fengli Guo Rhonda Trimble Ho Yi Mak 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(10):4640-4645
Dietary fat accumulates in lipid droplets or endolysosomal compartments that undergo selective expansion under normal or pathophysiological conditions. We find that genetic defects in a peroxisomal β-oxidation pathway cause size expansion in lipid droplets that are distinct from the lysosome-related organelles in Caenorhabditis elegans. Expansion of lipid droplets is accompanied by an increase in triglycerides (TAG) that are resistant to fasting- or TAG lipase-triggered lipolysis. Nevertheless, in mutant animals, a diet poor in vaccenic acid reduced the TAG level and lipid droplet size. Our results implicate peroxisomal dysfunction in pathologic lipid droplet expansion in animals and illustrate how dietary factors modulate the phenotype of such genetic defects. 相似文献
14.
Xian-Chun Tang Sudhakar S. Agnihothram Yongjun Jiao Jeremy Stanhope Rachel L. Graham Eric C. Peterson Yuval Avnir Aimee St. Clair Tallarico Jared Sheehan Quan Zhu Ralph S. Baric Wayne A. Marasco 《Proceedings of the National Academy of Sciences of the United States of America》2014,111(19):E2018-E2026
The newly emerging Middle East Respiratory Syndrome coronavirus (MERS-CoV) causes a Severe Acute Respiratory Syndrome-like disease with ∼43% mortality. Given the recent detection of virus in dromedary camels, zoonotic transfer of MERS-CoV to humans is suspected. In addition, little is known about the role of human neutralizing Ab (nAb) pressure as a driving force in MERS-CoV adaptive evolution. Here, we used a well-characterized nonimmune human Ab-phage library and a panning strategy with proteoliposomes and cells to identify seven human nAbs against the receptor-binding domain (RBD) of the MERS-CoV Spike protein. These nAbs bind to three different epitopes in the RBD and human dipeptidyl peptidase 4 (hDPP4) interface with subnanomolar/nanomolar binding affinities and block the binding of MERS-CoV Spike protein with its hDPP4 receptor. Escape mutant assays identified five amino acid residues that are critical for neutralization escape. Despite the close proximity of the three epitopes on the RBD interface, escape from one epitope did not have a major impact on neutralization with Abs directed to a different epitope. Importantly, the majority of escape mutations had negative impacts on hDPP4 receptor binding and viral fitness. To our knowledge, these results provide the first report on human nAbs against MERS-CoV that may contribute to MERS-CoV clearance and evolution. Moreover, in the absence of a licensed vaccine or antiviral for MERS, this panel of nAbs offers the possibility of developing human mAb-based immunotherapy, especially for health-care workers.Middle East Respiratory Syndrome coronavirus (MERS-CoV), a newly emergent subgroup C betacoronavirus, was first isolated in the Arabian Peninsula in 2012 (1). Similar to the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) that emerged in China in 2002, MERS-CoV causes severe respiratory tract infection, often in the lower respiratory tract and occasionally accompanied by renal disease (1). As of February 28, 2014, 184 cases with 80 deaths have been confirmed in 10 countries in the Middle East, Europe, and North Africa (www.who.int/csr/don/2014_02_28/en/). Although the human-to-human transmission rate is mild to moderate at the moment (2, 3), the increasing number of person-to-person transmissions raises concern for a more widespread regional outbreak or even global spread by international travelers, as occurred with SARS-CoV in 2002–2003. Limited information exists on the mechanisms that confer increased human-to-human transmission of MERS-CoV (4). However, mutational adaptation of the SARS-CoV Spike (S) protein for its receptor, angiotensin-converting enzyme 2 (ACE2) was a positive selection factor after zoonotic transfer to humans (5, 6).Phylogenetic analysis indicates that MERS-CoV is closely related to CoVs detected in Tylonycteris pachypus and Pipistrellus abramus bats in China, Nyctinomops laticaudatus bats in Mexico, and Nycteris cf. gambiensis bats in Ghana and Europe (7–9). An ∼190-bp nucleotide fragment that was genetically identical to the RNA-dependent RNA polymerase of MERS-CoV was detected in Taphozous perforatus bat specimens in the vicinity of the index case in Saudi Arabia (10). Two independent serological surveys of livestock found that dromedary camels had a high prevalence of neutralizing Abs (nAbs) against MERS-CoV (11, 12). Recently, MERS-CoV has been identified from dromedary camels on a farm associated with two human cases, but the transmission patterns remain unclear (13). More recently, a study detected Abs in all 151 samples of dromedary camel serum obtained from the United Arab Emirates in 2003, indicating that MERS-CoV or closely related CoVs existed in the United Arab Emirates long before the first human MERS cases (14, 15). A screen of cell lines derived from livestock and peridomestic small mammals on the Arabian Peninsula revealed that only ungulates such as goats and camels showed efficient replication of MERS-CoV (16). These findings suggest that bats and camels may play an important role in MERS-CoV transmission and that the range of species that can be infected with MERS-CoV may be even broader than currently known (17).The coronavirus S protein is a class I membrane fusion protein that represents the major envelope protein on the surface of CoVs. The S protein presents as a trimer and mediates receptor binding, membrane fusion, and virus entry. S also is the major target for nAbs (18). It has been reported that patients infected with MERS-CoV generated S protein-specific nAbs (19, 20). The cellular receptor for MERS-CoV has been identified as dipeptidyl peptidase 4 (DPP4, CD26), which is conserved across many species (21). The receptor-binding domain (RBD) of the virus S protein in complex with human DPP4 (hDPP4) has been characterized (22, 23).Although MERS-CoV has a lower reproduction number (R0) than SARS-CoV (0.69 vs. 0.80) (2), it has a much higher mortality rate (43% vs. 10%). Currently, no licensed vaccines or antivirals are available for the prevention or treatment of MERS. Combination treatment with IFN-α2b and ribavirin can moderate the host response and has been reported to improve clinical outcomes in MERS-CoV–infected rhesus macaques (24). MERS-CoV S protein vaccines based on modified vaccinia virus Ankara or Venezuelan Equine Encephalitis replicon particles and purified RBD can induce virus nAbs in mouse models (25–27). However, results of human studies have not been reported. Thus, an urgent medical need remains for the targeted prophylaxis and treatment of MERS.Human Ab engineering is a powerful tool that has been used for both discovery and therapeutic applications. We and others have proposed previously that human mAbs could be used in a outbreak setting for the prophylaxis and early treatment of emerging viral pathogens (28, 29). However, obtaining timely access to biological specimens from infected patients as a source of B cells for targeted selection or Ab-phage library construction is often challenging and can delay the discovery process (30–33). These restrictions have led us to use an ultra-large nonimmune human Ab-phage display library as a resource for the isolation of human nAbs to several emerging pathogens (29, 34, 35). With this Ab library resource and a unique panning strategy, we report the isolation and characterization of seven human nAbs that bind to three different epitopes at the MERS-CoV RBD–hDPP4 interface. We also investigated nAb-driven virus evolution and identified residues on the RBD that are critical for neutralization escape. These studies provide insight into the human nAb response that appears to impact MERS-CoV fitness and evolution. In addition, this panel of nAbs offers the possibility of developing a human mAb-based immunotherapy for the prevention and treatment of MERS. 相似文献
15.
Ekta K Bhardwaj Kathryn J Else Michael T Rogan Geoffrey Warhurst 《World journal of gastroenterology : WJG》2014,20(7):1797-1806
AIM:To investigate the influence of Trichuris muris(T.muris)infection in a mouse model of genetic susceptibility to inflammatory bowel disease,Mdr1a-/-.METHODS:Mdr1a-/-mice were housed under specific pathogen free conditions to slow the development of colitis and compared to congenic FVB controls.Mice were infected with approximately 200 embryonated ova from T.muris and assessed for worm burden and histological and functional markers of gut inflammation on day 19 post infection.RESULTS:Mdr1a-/-mice exhibited a marked increase in susceptibility to T.muris infection with a 10-fold increase in colonic worm count by day 19 pi compared to FVB controls.Prior to infection,Mdr1a-/-exhibitedlow-level mucosal inflammation with evidence of an enhanced Th1 environment.T.muris infection accelerated the progression of colitis in Mdr1a-/-as evidenced by marked increases in several indicators including histological damage score,mucosal CD4+T-cell and DC infiltration and dramatically increased production of proinflammatory cytokines.CONCLUSION:These data provide further evidence of the complex interaction between T.muris and an inflammatory bowel disease(IBD)-susceptible host which may have relevance to the application of helminth therapy in the treatment of human IBD. 相似文献
16.
In Kaposi’s sarcoma-associated herpesvirus (KSHV) oncogenesis, both latency and reactivation are hypothesized to potentiate tumor growth. The KSHV Rta protein is the lytic switch for reactivation. Rta transactivates essential genes via interactions with cofactors such as the cellular RBP-Jk and Oct-1 proteins, and the viral Mta protein. Given that robust viral reactivation would facilitate antiviral responses and culminate in host cell lysis, regulation of Rta’s expression and function is a major determinant of the latent-lytic balance and the fate of infected cells. Our lab recently showed that Rta transactivation requires the cellular peptidyl-prolyl cis/trans isomerase Pin1. Our data suggest that proline‑directed phosphorylation regulates Rta by licensing binding to Pin1. Despite Pin1’s ability to stimulate Rta transactivation, unchecked Pin1 activity inhibited virus production. Dysregulation of Pin1 is implicated in human cancers, and KSHV is the latest virus known to co-opt Pin1 function. We propose that Pin1 is a molecular timer that can regulate the balance between viral lytic gene expression and host cell lysis. Intriguing scenarios for Pin1’s underlying activities, and the potential broader significance for isomerization of Rta and reactivation, are highlighted. 相似文献
17.
18.
Miguel Torres-Rodríguez Mirella Gutiérrez-Arzaluz Violeta Mugica-álvarez Julia Aguilar-Pliego Sibele Pergher 《Materials》2012,5(5):872-881
Benzene alkylation with propylene was studied in the gas phase using a catalytic membrane reactor and a fixed-bed reactor in the temperature range of 200–300 °C and with a weight hourly space velocity (WHSV) of 51 h−1. β-zeolite was prepared by hydrothermal synthesis using silica, aluminum metal and TEAOH as precursors. The membrane’s XRD patterns showed good crystallinity for the β-zeolite film, while scanning electron microscopy SEM results indicated that its random polycrystalline film was approximately 1 μm thick. The powders’ specific area was determined to be 400 m2·g−1 by N2 adsorption/desorption, and the TPD results indicated an overall acidity of 3.4 mmol NH3·g−1. Relative to the powdered catalyst, the catalytic membrane showed good activity and product selectivity for cumene. 相似文献
19.
Cheng HH Tseng GY Yang HB Wang HJ Lin HJ Wang WC 《World journal of gastroenterology : WJG》2012,18(1):34-43
AIM: To determine the number of regulatory T cells (Tregs) in gastric mucosa of patients with gastritis, peptic ulcers and gastric cancer.METHODS: This study was a retrospective analysis of gastric antrum biopsy specimens from healthy controls (n = 22) and patients with gastritis (n = 30), peptic ulcer (n = 83), or gastric cancer (n = 32). Expression of CD4, CD25 and Foxp3 was determined by immunohistochemistry in three consecutive sections per sample.RESULTS: Compared with healthy controls, there was an increased number of CD25+ and Foxp3+ cells in patients with gastritis (P = 0.004 and P = 0.008), peptic ulcer (P < 0.001 and P < 0.001), and gastric cancer (P < 0.001 and P < 0.001). The ratio of CD25+/CD4+ or Foxp3+/CD4+ cells was also significantly higher in all disease groups (P < 0.001, respectively). The number of CD4+, CD25+, and Foxp3+ cells, and the ratio of CD25+/CD4+ and Foxp3+/CD4+ cells, were associated with the histological grade of the specimens, including acute inflammation, chronic inflammation, lymphoid follicle number, and Helicobacter pylori infection. The number of CD4+, CD25+ and Foxp3+ cells, and the ratio of CD25+/CD4+ and Foxp3+/CD4+ cells, were negatively associated with intestinal metaplasia among gastritis (P < 0.001, P < 0.001, P < 0.001, P = 0.002 and P = 0.002) and peptic ulcer groups (P = 0.013, P = 0.004, P < 0.001, P = 0.040 and P = 0.003).CONCLUSION: Tregs are positively associated with endoscopic findings of gastroduodenal diseases and histological grade but negatively associated with intestinal metaplasia in gastritis and peptic ulcer groups. 相似文献