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| 2. |
- Gambelunghe, G., et al.
(författare)
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Lack of association of CCR2-64I and CCR5-Delta 32 with type 1 diabetes and latent autoimmune diabetes in adults
- 2003
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Ingår i: Human Immunology. - 0198-8859 .- 1879-1166. ; 64:6, s. 629-632
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Tidskriftsartikel (refereegranskat)abstract
- It is well known that type I diabetes mellitus (T1DM) is a complex genetic disease resulting from the autoimmune destruction of pancreatic beta cells. Several genes have been associated with susceptibility and/or protection for T1DM, but the disease risk is mostly influenced by genes located in the class II region of the major histocompatibility complex. The attraction of leukocytes to tissues is essential for inflammation and the beginning of autoimmune reaction. The process is controlled by chemokines, which are chemotactic cytolines. Some studies have shown that CCR2-64I and CCR5-Delta32 might be important for protection of susceptibility to some immunologically-mediated disorders. In the present study, we demonstrate the lack of association between CCR2-64I and CCR5-Delta32 gene polymorphism and TIDM and we desrcibe a new method for a simple and more precise genotyping of the CCR2 gene.
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| 3. |
- Gharizadeh, B., et al.
(författare)
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Multiple group-specific sequencing primers for reliable and rapid DNA sequencing
- 2003
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Ingår i: Molecular and Cellular Probes. - : Elsevier BV. - 0890-8508 .- 1096-1194. ; 17:4, s. 203-210
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Tidskriftsartikel (refereegranskat)abstract
- Pyrosequencing(TM) technology is a bioluminometric DNA sequencing method that employs a cascade of four enzymes to deliver sequence signals. To date this technology has been limited to the sequencing of short stretches of DNA. As an improvement to this technique, we have introduced a bacterial group-specific, multiple sequencing primer approach that circumvents sequencing of less informative semi-conservative regions of the 16S rRNA gene. This new approach is suitable for challenging templates, improving sequence data quality, avoiding sequencing of non-specific amplification products, lessening sequencing time, and moreover, this strategy should open the way for many new applications in the future. The group-specific, multiple sequencing primers can be applied in the Sanger dideoxy sequencing method as well. In addition, we have improved the chemistry of the Pyrosequencing system enabling sequencing of longer stretches of DNA, which allows numerous new applications.
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| 4. |
- Gharizadeh, B., et al.
(författare)
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Multiple-primer DNA sequencing method
- 2003
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Ingår i: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 24:08-jul, s. 1145-1151
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Tidskriftsartikel (refereegranskat)abstract
- A multiple-primer DNA sequencing approach suitable for genotyping, detection and identification of microorganisms and viruses has been developed. In this new method two or m ore sequencing primers, combined in a pool, are added to a DNA sample of interest. The oligonucleotide that hybridizes to the DNA sample will function as a primer during the subsequent DNA sequencing procedure. This strategy is suited for selective detection and genotyping of relevant microorganisms and samples harboring different DNA targets such as,multiple variant/infected samples as well as unspecific amplification products. This method is used here in a model system for detection and typing of high-risk oncogenic human papilloma viruses (HPVs) in samples containing multiple infections/variants or unspecific amplification products. Type-specific sequencing primers were designed for four of the most oncogenic (high-risk) HPV types (HPV-16, HPV-18, HPV-33, and HPV-45). The primers were combined and added to a sample containing a mixture of one high-risk (16, 18, 33, or 45) and one or two low-risk types. The DNA samples were sequenced by the Pyrosequencing(TM) technology and the Sanger dideoxy sequencing method. Correct genotyping was achieved in all tested combinations. This multiple-sequencing primer approach also improved the sequence data quality for samples containing unspecific amplification products. The new strategy is highly suitable for diagnostic typing of relevant species/genotypes of microorganisms.
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| 5. |
- Gharizadeh, B., et al.
(författare)
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Type-specific multiple sequencing primers - A novel strategy for reliable and rapid genotyping of human papilloma viruses by pyrosequencing technology
- 2005
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Ingår i: Journal of Molecular Diagnostics. - 1525-1578 .- 1943-7811. ; 7:2, s. 198-205
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Tidskriftsartikel (refereegranskat)abstract
- DNA sequencing is the gold standard method for accurate microbial and viral typing. However, DNA sequencing techniques have been facing limitations in typing of human papillomaviruses when the specimen harbors multiple genotypes and yields nonspecific amplification products, resulting in nonspecific and noninterpretable sequence data. To address these limitations we have developed a type-specific multiple sequencing primer DNA-sequencing method. This new strategy is suitable for sequencing and typing of samples harboring different genotypes (co-infections with multiple genotypes) and yielding nonspecific amplifications, thus eliminating the need for nested polymerase chain reaction (PCR), stringent PCR conditions, and cloning. The new approach has also proved useful for amplicons containing low PCR yield or subdominant types, avoiding reperforming of amplifications. We have applied the multiple sequencing primer method for genotyping of clinically relevant human papillomaviruses in a clinical test panel by using a combined pool of seven type-specific sequencing primers for HPV-6, -11, -16, -18, -31, -33, and -45. Furthermore, we introduced a sequence pattern recognition approach when there was a plurality of genotypes in the sample to facilitate typing of more than one target DNA in the sample. The multiple sequencing primer method has proved to be a multifaceted approach for typing of human papillomaviruses by DNA sequencing technologies.
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| 6. |
- Gharizadeh, B., et al.
(författare)
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Typing of human papillomavirus by pyrosequencing
- 2001
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Ingår i: Laboratory Investigation. - : Elsevier BV. - 0023-6837 .- 1530-0307. ; 81:5, s. 673-679
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of using a new bioluminometric UNA sequencing technique, called pyrosequencing, for typing of human papillomaviruses (HPV) was investigated. A blinded pyrosequencing test was performed on an HPV test panel of 67 GP5+/GP6+ PCR-derived amplification products. The 67 clinical DNA samples were sequenced up to 25 bases and sequences were searched using BLAST. All of the samples were correctly genotyped by pyrosequencing and the results were unequivocally in accordance with the results obtained from conventional DNA sequencing. Pyrosequencing was found to be a fast and efficient tool for identifying individual HPV types. Furthermore, pyrosequencing has the capability of determining novel HPV types as well as HPV sequence variants harboring mutation(s). The method is robust and well suited for large-scale programs.
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| 7. |
- Lindback, E., et al.
(författare)
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DNA gyrase gene in Neisseria gonorrhoeae as indicator for resistance to ciprofloxacin and species verification
- 2005
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Ingår i: International Journal of STD and AIDS (London). - : SAGE Publications. - 0956-4624 .- 1758-1052. ; 16:2, s. 142-147
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Tidskriftsartikel (refereegranskat)abstract
- We have identified a unique region of eight amino acids in the quinolone resistance-determining region in the gyrA gene in Neisseria gonorrhoeae as an indicator of resistance to fluoroquinolones. We sequenced that region by the Pyrosequencing(TM) technology in 46 N. gonorrhoeae strains and 11 urine samples positive in AMPLICOR(TM) N. gonorrhoeae polymerase chain reaction (Roche Diagnostics), with corresponding isolates of N. gonorrhoeae. The results showed that 28 samples with minimum inhibitory concentration (MIC) of ciprofloxacin > 1 mg/L had mutations in positions 91 and 95. Fifteen samples with MIC 0.125-1.0 mg/L had either one or both of the mutations. The 14 susceptible samples had no mutations. The target region also discriminates N. gonorrhoeae from other species of Neisseria. Our conclusion is that gyrA is an indicator of resistance to ciprofloxacin in N. gonorrhoeae and sequencing by Pyrosequencing technology is a suitable tool for analysis of DNA in urine samples.
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| 8. |
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| 9. |
- Margeridon-Thermet, S, et al.
(författare)
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Ultra-deep pyrosequencing of hepatitis B virus quasispecies from nucleoside and nucleotide reverse-transcriptase inhibitor (NRTI)-treated patients and NRTI-naive patients
- 2009
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Ingår i: Journal of Infectious Diseases. - : University of Chicago Press. - 0022-1899 .- 1537-6613. ; 199:9, s. 1275-1285
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics of emerging nucleoside and nucleotide reverse-transcriptase inhibitor (NRTI) resistance in hepatitis B virus (HBV) are not well understood because standard dideoxynucleotide direct polymerase chain reaction (PCR) sequencing assays detect drug-resistance mutations only after they have become dominant. To obtain insight into NRTI resistance, we used a new sequencing technology to characterize the spectrum of low-prevalence NRTI-resistance mutations in HBV obtained from 20 plasma samples from 11 NRTI-treated patients and 17 plasma samples from 17 NRTI-naive patients, by using standard direct PCR sequencing and ultra-deep pyrosequencing (UDPS). UDPS detected drug-resistance mutations that were not detected by PCR in 10 samples from 5 NRTI-treated patients, including the lamivudine-resistance mutation V173L (in 5 samples), the entecavir-resistance mutations T184S (in 2 samples) and S202G (in 1 sample), the adefovir-resistance mutation N236T (in 1 sample), and the lamivudine and adefovir-resistance mutations V173L, L180M, A181T, and M204V (in 1 sample). G-to-A hypermutation mediated by the apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like family of cytidine deaminases was estimated to be present in 0.6% of reverse-transcriptase genes. Genotype A coinfection was detected by UDPS in each of 3 patients in whom genotype G virus was detected by direct PCR sequencing. UDPS detected low-prevalence HBV variants with NRTI-resistance mutations, G-to-A hypermutation, and low-level dual genotype infection with a sensitivity not previously possible.
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