Search results for "Sequence Analysis"
showing 10 items of 1349 documents
Effect of antiviral treatment and host susceptibility on positive selection in hepatitis C virus (HCV).
2007
Abstract We have conducted a large sequence study of the E1–E2 and NS5A regions of the HCV, subtypes 1a and b, both in patients previously treated with interferon, and untreated patients, who later responded, or not, to a combination therapy based on interferon plus ribavirin. We have examined the role played by the number of positively selected sites on disease progression and its relationship with several variables such as patients’ age, sex and their risk of acquiring the disease. We have detected three groups of patients that respond or not to combination therapy: responders of intermediate age, older non-responders and young non-responders, they possess an increasing average number of …
Trends for genetic variation of Hepatitis C Virus quasispecies in Human Immunodeficiency virus-1 coinfected patients
2007
Chronic infection by Hepatitis C Virus (HCV) causes liver fibrosis, which is accelerated by unknown mechanisms in patients with HIV-1 coinfection. The evolution of HCV quasispecies in this setting of coinfection is not fully understood. To compare HCV quasispecies between HIV-HCV coinfection and HCV monoinfection, we sequenced 340 HCV clones from the HVR-1 and NS3 regions at two different time points in two groups of treatment-naive patients with HCV-1a infection: (1) HIV-HCV positive (n=6); and (2) HIV negative-HCV positive (n=3). In HCV/HIV coinfection, we found a trend for reduced HCV genetic complexity and diversity, and a trend towards reduced dN/dS ratios in the HVR-1 region, especial…
Array comparative genomic hybridization analysis of chromosomal imbalances and their target genes in gastrointestinal stromal tumors.
2007
Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. The tumors characteristically harbor KIT or PDGFRA mutations, and mutant tumors respond to imatinib mesylate (Glivectrade mark). Chromosomal imbalances resulting in altered gene dosage are known to have a role in the molecular pathogenesis of these tumors, but the target genes remain to be identified. The present study aimed to identify some of these genes. In total, 35 GIST samples were screened for chromosomal imbalances by array-based comparative genomic hybridization. A cDNA array was used to define the minimal common overlapping areas of DNA copy number change. Eight confirmative, …
Genome-wide analysis for micro-aberrations in familial exstrophy of the bladder using array-based comparative genomic hybridization
2007
OBJECTIVE: Exstrophy of the bladder (EB) is part of the bladder-exstrophy-epispadias complex (BEEC). Because familial occurrence of BEEC is rare, exogenous factors are thought to play a major role in the etiology of most BEEC cases. We aimed to investigate a possible genetic basis of BEEC in a consanguineous kindred of Moroccan origin with three members showing the same phenotypic expression of BEEC. PATIENTS AND METHODS: The three affected males (two cousins and their maternal uncle) all presenting with nonsyndromic classic EB, were born in Morocco or The Netherlands. One Moroccan patient had an open bladder surface for 22 years due to late surgical reconstruction, avoided upright posture …
New pattern of EGFR amplification in glioblastoma and the relationship of gene copy number with gene expression profile
2010
Gene amplification is a process that is characterized by an increase in the copy number of a restricted region in a chromosome arm, and is frequently associated with an overexpression of the corresponding amplified gene. Amplified DNA can be organized either as extrachromosomal elements, repeated units at a single locus or scattered throughout the genome. The amplification of the gene for epidermal growth factor receptor (EGFR) is a common finding in glioblastomas and the amplified gene copies appears as double minutes. The aim of this study was to investigate the different patterns of EGFR amplification in 40 cases of glioblastoma using FISH analysis in metaphases and paraffin sections, an…
Cholinesterase variants: rapid characterisation by PCR/SSCP and evidence for molecular homogeneity.
1995
We have applied the technique of PCR-SSCP (polymerase chain reaction-single stranded conformation polymorphism) to characterise the molecular basis of cholinesterase deficiency and variants in a Jordanian family. PCR-SSCP proved to be a quick and sensitive method of screening cholinesterase variants in a clinical setting. An AG insertion at position 351 was found to cause a silent allele, for which the parents were heterozygous and three children homozygous. In addition, the father and two sons were heterozygous for an A to G transition at position 209, known to cause the dibucaine resistant variant. No linkage to the K variant was found, which has been reported previously in white populati…
A study on occupational exposure of Sicilian farmers to Giardia and Cryptosporidium
2013
Introduction. A cross-sectional study was undertaken to deter- mine the prevalence of Giardia and Cryptosporidium in calves of Palermo area (Sicily) and to evaluate the occupational risk associated with occurrence of zoonotic genotypes. Methods. A total of 217 faecal samples, from 149 calves (between 2 and 240 days of age) and 68 farmers, were collected in 19 cattle- farms of Palermo area. A questionnaire regarding demographic characteristics and personal hygienic measures was submitted to all farmers. All faecal samples were analyzed by Immunoflu- orescence assay and Polimerase Chain Reaction (PCR); geno- types were determined by DNA sequencing of Triose Phosphate Isomerase gene for Giardi…
Can the serological status of anti-HBc alone be considered a sentinel marker for detection of occult HBV infection?
2008
Some individuals have “occult” infection with hepatitis B virus (HBV), defined as presence of HBV genome in the serum or liver tissue without HBV surface antigen (HBsAg) in the serum. The aim of this study was to investigate whether serum antibodies against HBV core antigen in isolation (“anti-HBc alone”) are a useful marker of “occult” HBV in patients with or without hepatitis C virus (HCV) infection. “Anti-HBc alone” was detected in the sera of 119/6,544 (1.8%) asymptomatic outpatients referred to the diagnostic laboratory for routine testing for viral hepatitis, 62/607 (10.2%) drug users, and 42/195 (21.5%) patients with hepatocellular carcinoma. Using three in-house nested-PCR amplifica…
Detection of Epstein-Barr virus (EBV) DNA and antigens in oral mucosa of renal transplant patients without clinical evidence of oral hairy leukoplaki…
1998
The use of the polymerase chain reaction (PCR) to detect the presence of Epstein-Barr virus (EBV) DNA in oral mucosa in the absence of specific lesions gives rise to the problem of identifying the real viral replication sites. To verify whether the detection of EBV is due to salivary contamination or its true replicative capacity in oral mucosa, saliva samples and exfoliated cells from four different oral mucosa sites were taken from 40 renal transplant patients and 20 normal subjects for examination by PCR using two pairs of primers specific for the BamHI-L and BamHI-K genomic regions. EBV-specific sequences were detected in one or more of the oral mucosa samples from 29 transplant patient…
Hepatitis B and C virus variants in long-term immunosuppressed renal transplant patients in Latvia.
2004
The incidence of genome variants of hepatitis B and hepatitis C viruses among 38 long-term (2–15 years) immunosuppressed patients after renal transplantation and 10 patients undergoing dialysis was investigated. Twelve patients had only HBV infection, 9 had only HCV infection and 14 were co-infected. Regions corresponding to the HBV X/EnII/BCP, preC/C, preS/S and to the HCV core were sequenced for molecular characterization of the HBV and HCV genomes. Fifty-seven percent of HBV DNA isolates belonged to genotype D and 42% to genotype A, whereas 77% of HCV RNA isolates belonged to genotype 1b and only 17% to genotype 3a. One sample (6%) was of genotype 2c. Detailed analysis of the above-menti…