Search results for "Digestive System"
showing 10 items of 1747 documents
O6-methylguanine DNA methyltransferase and p53 status predict temozolomide sensitivity in human malignant glioma cells
2006
Temozolomide (TMZ) is a methylating agent which prolongs survival when administered during and after radiotherapy in the first-line treatment of glioblastoma and which also has significant activity in recurrent disease. O6-methylguanine DNA methyltransferase (MGMT) is a DNA repair enzyme attributed a role in cancer cell resistance to O6-alkylating agent-based chemotherapy. Using a panel of 12 human glioma cell lines, we here defined the sensitivity to TMZ in acute cytotoxicity and clonogenic survival assays in relation to MGMT, mismatch repair and p53 status and its modulation by dexamethasone, irradiation and BCL-X(L). We found that the levels of MGMT expression were a major predictor of T…
Inhibition of O6-Methylguanine-DNA Methyltransferase by Glucose-Conjugated Inhibitors: Comparison with Nonconjugated Inhibitors and Effect on Fotemus…
2004
The DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) is an important suicide enzyme involved in the defense against O(6)-alkylating mutagens. It also plays a role in the resistance of tumors to anticancer drugs targeting the O(6)-position of guanine, such as temozolomide and fotemustine. Several potent MGMT inhibitors have been developed sensitizing cells to O(6)-alkylating agents. Aimed at targeting MGMT inhibitors to tumor cells, we synthesized MGMT inhibitory compounds conjugated with glucose to improve uptake in tumor cells. Here, we compared O(6)-benzylguanine, O(6)-2-fluoropyridinylmethylguanine (O(6)FPG), O(6)-3-iodobenzylguanine, O(6)-4-bromothenylguanine, and O(6)…
Hepatocytes of double-transgenic mice expressing high levels of hepatitis B virus e antigen and interferon-gamma are not injured by HBeAg specific au…
2000
Seroconversion from HBeAg to alphaHBe of persons chronically infected by HBV is usually associated with a transient exacerbation of liver disease and subsequent normalization of liver histology. It is speculated that these clinico-pathological features may be due to the activation of cytodestructive mechanisms by alphaHBe antibodies. The aim of the present study was to investigate the pathogenic potential of alphaHBe antibodies in a transgenic mouse model. Therefore, alphaHBe autoantibodies were elicited in double-transgenic mice expressing high amounts of HBeAg and interferon-gamma in the liver. Interferon-gamma has reviously been shown to play an important role in the development of hepat…
Microarray-Based Gene Expression Analysis of Hepatocellular Carcinoma
2009
Microarray studies have successfully shed light on various aspects of the molecular mechanisms behind the development of hepatocellular carcinoma (HCC), such as the identification of novel molecular subgroups and the genetic profiles associated with metastasis and venous invasion. These experiments, mainly comprising genome wide profiling, potentially represent the basis of novel targeted therapeutic strategies in HCC. In response, we summarize the multiple reported expression profiles in HCC associated with HCC development, novel subgroups, venous invasion and metastasis.
Increase in gut microbiota after immune suppression in baculovirus-infected larvae.
2013
Spodoptera exigua microarray was used to determine genes differentially expressed in S. exigua cells challenged with the species-specific baculovirus SeMNPV as well as with a generalist baculovirus, AcMNPV. Microarray results revealed that, in contrast to the host transcriptional shut-off that is expected during baculovirus infection, S. exigua cells showed a balanced number of up- and down-regulated genes during the first 36 hours following the infection. Many immune-related genes, including pattern recognition proteins, genes involved in signalling and immune pathways as well as immune effectors and genes coding for proteins involved in the melanization cascade were found to be down-regul…
Association of Maternal Secretor Status and Human Milk Oligosaccharides With Milk Microbiota: An Observational Pilot Study
2019
Background and Objectives: Breast milk contains several bioactive factors including oligosaccharides (HMO) and microbes that shape the infant gut microbiota. HMO profile is determined by secretor status, however their influence on milk microbiota is still uncovered. This study is aimed to determine the impact of the FUT2 genotype on the milk microbiota during the first month of lactation and the association with HMO. Methods: Milk microbiota from 25 healthy lactating women was determined by quantitative PCR and 16S gene pyrosequencing. Secretor genotype was obtained by PCR-RFLPs and by HMO identification and quantification. Results: The most abundant bacteria were Staphylococcus and Strepto…
One-step polymerase chain reaction-based typing of Helicobacter pylori vacA gene: association with gastric histopathology.
2000
Heterogeneity of the Helicobacter pylori vacA gene may be associated with bacterial virulence and presentation. In this study, the possible correlation between vacA genotypes and gastric histopathology was investigated. Using a modified one-step polymerase chain reaction (PCR)-based method, 122 of 131 H. pylori isolates obtained from 63 of 67 patients from Germany were classified into distinct vacA genotypes according to their signal sequence (s1 or s2) and their midregion alleles (m1 or m2). A possible subtype of m1, now alluded to as m3, was identified in one-third of the isolates. Signal sequence s1 was significantly associated with higher H. pylori density but not with gastric inflammat…
Immunological Diagnosis of Human Cystic Echinococcosis: Utility of Discriminant Analysis Applied to the Enzyme-Linked Immunoelectrotransfer Blot
1999
ABSTRACT An enzyme-linked immunoelectrotransfer blot for the diagnosis of human hydatid disease was performed, and the different antibody responses were analyzed by a discriminant analysis. This multivariate technique gave us, first, a selection of the most important responses against Echinococcus granulosus infection and, second, a procedure for the classification of patients into two groups: patients with hydatid disease and patients without a history of hydatid disease. This method was applied to 67 patients, 25 with active hydatid cysts (24 hepatic and 1 pulmonary) and 42 without a history of hydatid disease and was compared with the results obtained by conventional serology: indirect h…
The cultivable human oral gluten-degrading microbiome and its potential implications in coeliac disease and gluten sensitivity
2013
AbstractCoeliac disease is characterized by intestinal inflammation caused by gluten, proteins which are widely contained in the Western diet. Mammalian digestive enzymes are only partly capable of cleaving gluten, and fragments remain that induce toxic responses in patients with coeliac disease. We found that the oral microbiome is a novel and rich source of gluten-degrading organisms. Here we report on the isolation and characterization of the cultivable resident oral microbes that are capable of cleaving gluten, with special emphasis on the immunogenic domains. Bacteria were obtained by a selective culturing approach and enzyme activities were characterized by: (i) hydrolysis of paranitr…
Detection of hepatitis B virus DNA by polymerase chain reaction in serum and liver of children with chronic hepatitis B negative for hepatitis B viru…
1992
Hepatitis B virus (HBV) DNA was detected by polymerase chain reaction in the serum of 87 and liver tissue of 40 children with chronic hepatitis B, negative for HBV DNA by dot blot and Southern blot hybridization, respectively. In sera HBV DNA could be detected in 73 hepatitis B surface antigen carriers; 14 were hepatitis B e antigen (HBeAg), 56 were anti-HBe-seropositive and 3 had neither HBeAg nor positive anti-HBe. In 14 anti-HBe-positive patients no HBV DNA could be found. Viral sequences in liver tissue were present in 33 specimens; 20 were HBeAg and 13 were anti-HBe-seropositive. All of the 7 negative children had anti-HBe. Our results confirm polymerase chain reaction to be a more sen…