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- Omar, Omar, et al.
(author)
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In vivo gene expression in response to anodically oxidized versus machined titanium implants.
- 2010
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In: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 92:4, s. 1552-1566
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Journal article (peer-reviewed)abstract
- A quantitative polymerase chain reaction technique (qPCR) in combination with scanning electron microscopy was applied for the evaluation of early gene expression response and cellular reactions close to titanium implants. Anodically oxidized and machined titanium miniscrews were inserted in rat tibiae. After 1, 3, and 6 days the implants were unscrewed and the surrounding bone was retrieved using trephines. Both the implants and bone were analyzed with qPCR. A greater amount of cells, as indicated with higher expression of 18S, was detected on the oxidized surface after 1 and 6 days. Significantly higher osteocalcin (at day 6), alkaline phosphatase (at days 3 and 6), and cathepsin K (at day 3) expression was demonstrated for the oxidized surface. Higher expression of tumor necrosis factor-alpha (at day 1) and interleukin-1beta (at days 1 and 6) was detected on the machined surfaces. SEM revealed a higher amount of mesenchymal-like cells on the oxidized surface. The results show that the rapid recruitment of mesenchymal cells, the rapid triggering of gene expression crucial for bone remodeling and the transient nature of inflammation, constitute biological mechanisms for osseointegration, and high implant stability associated with anodically oxidized implants. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2009.
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- Slotte, Christer, 1954, et al.
(author)
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Gene Expression of Inflammation and Bone Healing in Peri-Implant Crevicular Fluid after Placement and Loading of Dental Implants. A Kinetic Clinical Pilot Study Using Quantitative Real-Time PCR.
- 2012
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In: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 14:5, s. 723-736
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Journal article (peer-reviewed)abstract
- Purpose: Early detection of healing complications after placement of dental implants is a pressing but elusive goal. This paper proposes a non-invasive diagnostic tool for monitoring healing- and peri-implant disease specific genes, complementary to clinical evaluations. Material and Methods: Eighteen partially edentulous patients were recruited to this pilot study. Three Brånemark TiUnite® implants/patient (Nobel Biocare) were placed in a one-stage procedure. Abutments with smooth or rough (TiUnite®) surface were placed. The test group (n=9) received fixed bridges (immediate loading), whereas the control group (n=9) implants were loaded 3 months after surgery. In addition to clinical measurements, crevicular fluid was collected using paper strips at the implant abutments 2, 14, 28, and 90 days postoperative. mRNA was extracted, purified, and converted to cDNA. Quantitative PCR assays for IL-1β, TNF-α, Osteocalcin (OC), Alkaline Phosphatase (ALP), Cathepsin K, Tartrate Resistant Acid Phosphatase, and 18S ribosomal RNA were designed and validated. Relative gene expression levels were calculated. Results: One implant was lost in the control group and three in the test group. In one test patient, one implant showed lowered stability after 2 to 4 weeks and was unloaded. Later implant stability improved which allowed for loading after 3 to 4 months. TNF-α and ALP most commonly showed correlation with clinical parameters followed by IL-1β and OC. The strongest correlation was found for TNF-α with clinical complications at 2 and 14 days (p=.01/r=-048, and p=.0004/r=-0.56, respectively; test and control groups together). In some cases, gene expression predicted clinical complications (TNF-α, ALP, CK). Conclusion: This study is based on samples from few individuals; still, some genes showed correlation with clinical findings. Further studies are needed to refine and optimize the sampling process, to find the appropriate panel, and to validate gene expression for monitoring implant healing.
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- Ståhlberg, Anders, 1975, et al.
(author)
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Comparison of reverse transcription quantitative real-time PCR, flow cytometry, and immunohistochemistry for detection of monoclonality in lymphomas.
- 2014
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In: ISRN oncology. - : Hindawi Limited. - 2090-5661 .- 2090-567X. ; 2014
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Journal article (peer-reviewed)abstract
- In healthy humans, 60-70% of the B lymphocytes produce kappa light chains, while the remaining cells produce lambda light chains. Malignant transformation and clonal expansion of B lymphocytes lead to an altered kappa:lambda expression ratio, which is an important diagnostic criteria of lymphomas. Here, we compared three methods for clonality determination of suspected B cell lymphomas. Tumor biopsies from 55 patients with B cell malignancies, 5 B-lymphoid tumor cell lines, and 20 biopsies from patients with lymphadenitis were analyzed by immunohistochemistry, flow cytometry, and reverse transcription quantitative real-time PCR. Clonality was determined by immunohistochemistry in 52/53 cases, flow cytometry in 30/39 cases, and reverse transcription quantitative real-time PCR in 33/55 cases. In conclusion, immunohistochemistry was superior to flow cytometry and reverse transcription quantitative real-time PCR for clonality identification. Flow cytometry and reverse transcription quantitative real-time PCR analysis has complementary values. In a considerable number of cases tumor cells produced both kappa and lambda light chain transcripts, but only one type of light chain peptide was produced.
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- Ståhlberg, Anders, 1975, et al.
(author)
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Quantitative real-time PCR for cancer detection: the lymphoma case.
- 2005
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In: Expert review of molecular diagnostics. - : Informa UK Limited. - 1473-7159 .- 1744-8352. ; 5:2, s. 221-30
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Research review (peer-reviewed)abstract
- Advances in the biologic sciences and technology are providing molecular targets for diagnosis and treatment of cancer. Lymphoma is a group of cancers with diverse clinical courses. Gene profiling opens new possibilities to classify the disease into subtypes and guide a differentiated treatment. Real-time PCR is characterized by high sensitivity, excellent precision and large dynamic range, and has become the method of choice for quantitative gene expression measurements. For accurate gene expression profiling by real-time PCR, several parameters must be considered and carefully validated. These include the use of reference genes and compensation for PCR inhibition in data normalization. Quantification by real-time PCR may be performed as either absolute measurements using an external standard, or as relative measurements, comparing the expression of a reporter gene with that of a presumed constantly expressed reference gene. Sometimes it is possible to compare expression of reporter genes only, which improves the accuracy of prediction. The amount of biologic material required for real-time PCR analysis is much lower than that required for analysis by traditional methods due to the very high sensitivity of PCR. Fine-needle aspirates and even single cells contain enough material for accurate real-time PCR analysis.
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- Zoric, Neven, et al.
(author)
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Quantitative PCR: A promising technique investigating the early bone-implant interface
- 2007
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In: Abstract, European Association for Osseointegration (EAO), 16th Annual Scientific Meeting, Barcelona, Spain. ; 25-27 October
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Conference paper (peer-reviewed)abstract
- Objectives: Studies on the early tissue response to materials are difficult due to the inaccessibility of the interface zone and lack of sensitive techniques. The purpose of the present study was to apply quantitative PCR (qPCR) in combination with LM and SEM for the evaluation of early gene expression response as well as cellular reactions close to titanium implants. Experimental methods: Anodically oxidized titanium (TiUniteTM; Nobel Biocare AB) and machined titanium implants (2mm×2mm) were inserted in the rat tibia. After 1,3, and 6 days, implants were unscrewed and surrounding bone was retrieved. Both the implants and bone were analyzed with qPCR, routine histology and SEM. The amount of mRNA was normalized to 18S protein subunit. Results: After the initial inflammatory response, the tissue located inside the threads became rapidly organized. SEM analysis showed mesenchymal-like cells extending their processes into the pores of the anodically oxidized surface. qPCR demonstrated significantly higher 18S around anodically oxidized screws and in the surrounding tissues. Alkaline phosphatase (osteoblast marker), TRAP and Cathepsin K (osteoclast markers) mRNA, but not the inflammatory markers (TNF-alpha and IL-1beta) were expressed at different levels around the two surfaces. Conclusions: The results demonstrate that the experimental model and qPCR provide interesting possibilities to analyze the mechanisms of osseointegration. Furthermore, remodelling and in particular the molecular processes occur at implant surfaces in vivo already 3 days after implantation. Support: Swedish Research Council and the Institute for Biomaterials and Cell Therapy, Göteborg, Sweden
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