Staale Lyngstadaas - Academia.edu (original) (raw)
Papers by Staale Lyngstadaas
Tidsskrift for Den norske legeforening, May 10, 1996
The Norwegian Dental Journal, 1991
Tumour viruses are thought to contribute to the development of one fifth of all human cancers, al... more Tumour viruses are thought to contribute to the development of one fifth of all human cancers, although the mechanisms involved are still obscure. Human papilloma virus (HPV) is a DNA virus associated with oral carcinomas. It has been shown that virus DNA has to become integrated into cellular DNA in order to transform normal to malignant cells. Cellular oncogenes and tumour suppressor genes are potential cancer genes. They are involved in the control of growth and differentiation of normal cells. It is known that structural or regulatory changes (activation) of these genes will lead to malignant transformation. Virus integration will sometimes take place in close relation to cellular oncogenes. Such incorporation may result in oncogene activation. Other cellular factors that may contribute to the development of oral squamous cell carcinoma are also discussed.
Journal of Anatomy, 1996
Maxillary and mandibular incisors of mice aged 5 wk were sectioned and ground along various plane... more Maxillary and mandibular incisors of mice aged 5 wk were sectioned and ground along various planes, acidetched and observed by scanning electron microscopy (SEM). The general design of the enamel structure resembled rat incisor enamel with an uniserial lamellar pattern of prisms in the inner enamel and incisally directed parallel prisms in the outer enamel. The centrolabial thickness of the enamel was about 60 microns in the maxillary and about 95 microns in the mandibular incisor. The angle between prism rows and enamel-dentine junction was about 70 degrees in the maxillary and about 45 degrees in the mandibular incisor, while the angle of decussation, which increased from the enamel-dentine junction towards the outer enamel, was 50-95 degrees and 30-80 degrees respectively. The angle between outer enamel prisms and enamel surface was about 12 degrees in the maxillary and 5-15 degrees in the mandibular incisor. The outer 1/2-1/3 of the outer enamel contained iron and was more acid-...
Den Norske tannlaegeforenings tidende, 1990
Den Norske tannlaegeforenings tidende, 1990
International Journal of Oral and Maxillofacial Surgery
The use of two particulate bone graft substitute materials in experimental narrow marginal peri-i... more The use of two particulate bone graft substitute materials in experimental narrow marginal peri-implant bone defects was investigated with respect to early bone healing and implant stability. Porous titanium granules, oxidized white porous titanium granules (WPTG), and demineralized bovine bone mineral (DBBM) were characterized in vitro, after which the two latter materials were tested in experimental peri-implant bone defects in six minipigs, with empty defects as control. After mandibular premolar extraction, the top 5mm of the alveoli were widened to 6mm in diameter, followed by the placement of six implants, three on each side, in each pig. Six weeks of healing was allowed. The WPTG showed better mechanical properties. No significant differences in resonance frequency analysis were found directly after compacting or healing, and similar quantities of defect bone formation were observed on micro-computed tomography for all groups. Histomorphometric analysis demonstrated a more coronal bone-to-implant contact in the DBBM group, which also displayed more defect bone fill as compared to the WPTG group. The better mechanical properties observed for WPTG appear of negligible relevance for the early stability and osseointegration of implants.
Journal of the European Ceramic Society, 2009
... Specimens were mounted vertically on a plastic support and rotated 180° around the ... which ... more ... Specimens were mounted vertically on a plastic support and rotated 180° around the ... which grayscale tomograms of scaffolds were most accurately represented by their binaries counterparts in ... The scaffolds were gold sputtered (MACHINE) and examined in SEM (Tabletop SEM ...
Journal of Materials Science: Materials in Medicine, 2013
Critical Reviews in Oral Biology & Medicine, 2001
The assessment of genetic controls for sequential developmental processes such as tooth formation... more The assessment of genetic controls for sequential developmental processes such as tooth formation and biomineralization is often difficult in transgenic "knockout" models, where phenotypes reflect only the permanent eradication of a gene, and reveal little about the dynamic range of expression for the gene(s) involved. One promising strategy to overcome this problem is through the use of ribozymes, a class of metalloenzymes made entirely of ribonucleic acid (RNA), that are capable of cleaving other RNA molecules in a catalytic fashion. Their activity can be targeted against specific mRNAs by selection of unique sequences flanking a conserved catalytic motif. In synthetic ribozymes, specificity, stability, and cell permeability can be dramatically improved by the incorporation of chemically modified ribonucleotides. This review focuses on the design and application of hammerhead ribozymes, the best-known and most widely used class of RNA-based enzymes. So far, except for a ...
Clinical Oral Implants Research, 2013
The aim of this in vitro study was to compare the effect of combined chemical and mechanical debr... more The aim of this in vitro study was to compare the effect of combined chemical and mechanical debridement of titanium (Ti) surfaces inoculated with Staphylococcus epidermidis, compared with the effect of chemical debridement alone. Different Ti surfaces were characterized with respect to roughness and subsequently inoculated with S. epidermidis. NaCl (0.9 vol.%), EDTA (12 vol.%), H₂O₂ (3 vol.%) or H₂O₂ + TiO₂ nanoparticles served as chemical debridement agents, while TiBrush was used as the mechanical debridement tool. Safranin staining assessed biomass still attached to surfaces after debridement. Biofilm viability was assessed after re-incubation of the debrided samples. SEM analysis was performed before and after the cleaning process. Surface average roughness (Sa ) of the samples was measured at 2.22 ± 0.19 μm for group A, 0.19 ± 0.02 μm for group B, and 1.99 ± 0.10 μm for group C. When chemical debridement agents were used alone, H₂O₂-containing products were most efficient in reducing the biomass load. The surface roughness did not affect the outcome of chemical debridement. However, when combining chemical and mechanical debridement, a further reduction of biofilm load and viability was observed with best effect on the smoothest surface. Combining H₂O₂-containing chemical agents with mechanical debridement (TiBrush) provided best reduction in biofilm mass and re-growth, when studied in vitro.
Journal of Biomaterials Applications, 2014
The aim of this study was to investigate the effect of TiO2 scaffold (SC) coated with an alginate... more The aim of this study was to investigate the effect of TiO2 scaffold (SC) coated with an alginate hydrogel containing a proline-rich peptide (P2) on osteoblast proliferation and differentiation in vitro. Peptide release was evaluated and a burst release was observed during the first hours of incubation, and then progressively released overtime. No changes were observed in the cytotoxicity after 48 h of seeding MC3T3-E1 cells on the coated and uncoated TiO2 SC. The amount of cells after 7 days was higher on uncoated TiO2 SC than on alginate-coated TiO2 SC, measured by DNA content and scanning electron microscope imaging. In addition, while lower expression of integrin beta1 was detected for alginate-coated TiO2 SC at this time point, similar gene expression was observed for other integrins, fibronectin-1, and several osteoblast differentiation markers. After 21 days, gene expression of integrin beta3, fibronectin-1, osterix, and collagen-I was increased in alginate-coated compared to TiO2 SC. Moreover, increased gene expression of integrin alpha8, bone morphogenetic protein 2, interleukin-6, and collagen-I was found on P2 alginate-coated TiO2 SC compared to alginate-coated TiO2 SC. In conclusion, our results indicate that alginate-coated TiO2 SC can act as a matrix for delivery of proline-rich peptides increasing osteoblast differentiation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Adsorption of biomolecules onto material surfaces involves a potentially complex mechanism where ... more Adsorption of biomolecules onto material surfaces involves a potentially complex mechanism where molecular species interact to varying degrees with a heterogeneous material surface. Surface adsorption studies by atomic force microscopy, sum frequency generation spectroscopy, and solid-state NMR detect the structures and interactions of biomolecular species that are bound to material surfaces, which, in the absence of a solid−liquid interface, do not exchange rapidly between surface-bound forms and free molecular species in bulk solution. Solution NMR has the potential to complement these techniques by detecting and studying transiently bound biomolecules at the liquid−solid interface. Herein, we show that dark-state exchange saturation transfer (DEST) NMR experiments on gel-stabilized TiO 2 nanoparticle (NP) samples detect several forms of biomolecular adsorption onto titanium(IV) oxide surfaces. Specifically, we use the DEST approach to study the interaction of amino acids arginine (Arg), lysine (Lys), leucine (Leu), alanine (Ala), and aspartic acid (Asp) with TiO 2 rutile NP surfaces. Whereas Leu, Ala, and Asp display only a single weakly interacting form in the presence of TiO 2 NPs, Arg and Lys displayed at least two distinct bound forms: a species that is surface bound and retains a degree of reorientational motion and a second more tightly bound form characterized by broadened DEST profiles upon the addition of TiO 2 NPs. Molecular dynamics simulations indicate different surface bound states for both Lys and Arg depending on the degree of TiO 2 surface hydroxylation but only a single bound state for Asp regardless of the degree of surface hydroxylation, in agreement with results obtained from the analysis of DEST profiles.
International Journal of Molecular Sciences
In this study, the effect on osteoclast activity in vitro and in vivo of titanium implants that w... more In this study, the effect on osteoclast activity in vitro and in vivo of titanium implants that were coated with quercitrin was evaluated. Titanium surfaces were covalently coated with the flavonoid quercitrin. The effect of the surfaces on osteoclastogenesis was first tested in vitro on RAW264.7 cells that were supplemented with receptor activator of nuclear factor kappa-B ligand (RANKL) to generate osteoclast-like cells by tartrate-resistant acid phosphatase (TRAP) inmunostaining after five days of culture, and by analysis of the mRNA expression levels of markers related to bone resorption after seven days of culture. A rabbit tibial model was used to evaluate the in vivo biological response to the implant surfaces after eight weeks of healing, analyzing the lactate dehydrogenase (LDH) and the alkaline phosphatase (ALP) activities in the wound fluid that were present at the implant interface and the peri-implant bone mRNA expression levels of several markers related to inflammatio...
Journal of Clinical Periodontology
Bovine xenograft materials, followed by synthetic biomaterials, which unfortunately still lack do... more Bovine xenograft materials, followed by synthetic biomaterials, which unfortunately still lack documented predictability and clinical performance, dominate the market for the cranio-maxillofacial area. In Europe, new stringent regulations are expected to further limit the allograft market in the future. Aim: Within this narrative review, we discuss possible future biomaterials for bone replacement. Scientific Rationale for Study: Although the bone graft (BG) literature is overflooded, only a handful of new BG substitutes are clinically available. Laboratory studies tend to focus on advanced production methods and novel biomaterial features, which can be costly to produce. Practical Implications: In this review, we ask why such a limited number of BGs are clinically available when compared to extensive laboratory studies. We also discuss what features are needed for an ideal BG. Results: We have identified the key properties of current bone substitutes and have provided important information to guide clinical decision-making and generate new perspectives on bone substitutes. Our results indicated that different mechanical and biological properties are needed despite each having a broad spectrum of variations. Conclusions: We foresee bone replacement composite materials with higher levels of bioactivity, providing an appropriate balance between bioabsorption and volume maintenance for achieving ideal bone remodelling.
The present invention relates to the ?eld of terminal ?shing tackle, such as leaders, bait, lures... more The present invention relates to the ?eld of terminal ?shing tackle, such as leaders, bait, lures and/or ?ies, made from natural and/ or synthetic ?bres and coated With a uniform nano-thin metal oxide layer. More particularly, the present invention relates to terminal ?shing tackle that has a hydro phobic, hydrophilic, super hydrophilic, Water sealant, colour introducing, photocatalytic, UV-protecting, anti-microbial, and/ or anti-fouling property, Wherein said property is gained by a coating using advanced methods for atomic layer depo sition, or combinations of atomic layer deposition and addi tional coating on said tackle. In a preferred embodiment, said coating is selected from Carbon, Gold, Palladium, TiO2, Al2O3, SiO2 and combinations thereof. BACKGROUND TO THE INVENTION [0002] There are many different styles of ?shing and many of them involve the use of a line, and a lure, spinner, arti?cial ?y or other attractant. Fly ?shing is a style of ?shing in Which a very light Weight "?y" is attached to the end of a ?shing line. The Word "?y" is used to describe the device that attracts the attention of the ?sh and causes it to strike. This "?y" can be a construction Which is designed to simulate the general shape, colour, siZe, and look of a ?y or other insect or nymph or spaWn or small ?sh Which is naturally occurring in the ?sh's environment.
Tidsskrift for Den norske legeforening, May 10, 1996
The Norwegian Dental Journal, 1991
Tumour viruses are thought to contribute to the development of one fifth of all human cancers, al... more Tumour viruses are thought to contribute to the development of one fifth of all human cancers, although the mechanisms involved are still obscure. Human papilloma virus (HPV) is a DNA virus associated with oral carcinomas. It has been shown that virus DNA has to become integrated into cellular DNA in order to transform normal to malignant cells. Cellular oncogenes and tumour suppressor genes are potential cancer genes. They are involved in the control of growth and differentiation of normal cells. It is known that structural or regulatory changes (activation) of these genes will lead to malignant transformation. Virus integration will sometimes take place in close relation to cellular oncogenes. Such incorporation may result in oncogene activation. Other cellular factors that may contribute to the development of oral squamous cell carcinoma are also discussed.
Journal of Anatomy, 1996
Maxillary and mandibular incisors of mice aged 5 wk were sectioned and ground along various plane... more Maxillary and mandibular incisors of mice aged 5 wk were sectioned and ground along various planes, acidetched and observed by scanning electron microscopy (SEM). The general design of the enamel structure resembled rat incisor enamel with an uniserial lamellar pattern of prisms in the inner enamel and incisally directed parallel prisms in the outer enamel. The centrolabial thickness of the enamel was about 60 microns in the maxillary and about 95 microns in the mandibular incisor. The angle between prism rows and enamel-dentine junction was about 70 degrees in the maxillary and about 45 degrees in the mandibular incisor, while the angle of decussation, which increased from the enamel-dentine junction towards the outer enamel, was 50-95 degrees and 30-80 degrees respectively. The angle between outer enamel prisms and enamel surface was about 12 degrees in the maxillary and 5-15 degrees in the mandibular incisor. The outer 1/2-1/3 of the outer enamel contained iron and was more acid-...
Den Norske tannlaegeforenings tidende, 1990
Den Norske tannlaegeforenings tidende, 1990
International Journal of Oral and Maxillofacial Surgery
The use of two particulate bone graft substitute materials in experimental narrow marginal peri-i... more The use of two particulate bone graft substitute materials in experimental narrow marginal peri-implant bone defects was investigated with respect to early bone healing and implant stability. Porous titanium granules, oxidized white porous titanium granules (WPTG), and demineralized bovine bone mineral (DBBM) were characterized in vitro, after which the two latter materials were tested in experimental peri-implant bone defects in six minipigs, with empty defects as control. After mandibular premolar extraction, the top 5mm of the alveoli were widened to 6mm in diameter, followed by the placement of six implants, three on each side, in each pig. Six weeks of healing was allowed. The WPTG showed better mechanical properties. No significant differences in resonance frequency analysis were found directly after compacting or healing, and similar quantities of defect bone formation were observed on micro-computed tomography for all groups. Histomorphometric analysis demonstrated a more coronal bone-to-implant contact in the DBBM group, which also displayed more defect bone fill as compared to the WPTG group. The better mechanical properties observed for WPTG appear of negligible relevance for the early stability and osseointegration of implants.
Journal of the European Ceramic Society, 2009
... Specimens were mounted vertically on a plastic support and rotated 180° around the ... which ... more ... Specimens were mounted vertically on a plastic support and rotated 180° around the ... which grayscale tomograms of scaffolds were most accurately represented by their binaries counterparts in ... The scaffolds were gold sputtered (MACHINE) and examined in SEM (Tabletop SEM ...
Journal of Materials Science: Materials in Medicine, 2013
Critical Reviews in Oral Biology & Medicine, 2001
The assessment of genetic controls for sequential developmental processes such as tooth formation... more The assessment of genetic controls for sequential developmental processes such as tooth formation and biomineralization is often difficult in transgenic "knockout" models, where phenotypes reflect only the permanent eradication of a gene, and reveal little about the dynamic range of expression for the gene(s) involved. One promising strategy to overcome this problem is through the use of ribozymes, a class of metalloenzymes made entirely of ribonucleic acid (RNA), that are capable of cleaving other RNA molecules in a catalytic fashion. Their activity can be targeted against specific mRNAs by selection of unique sequences flanking a conserved catalytic motif. In synthetic ribozymes, specificity, stability, and cell permeability can be dramatically improved by the incorporation of chemically modified ribonucleotides. This review focuses on the design and application of hammerhead ribozymes, the best-known and most widely used class of RNA-based enzymes. So far, except for a ...
Clinical Oral Implants Research, 2013
The aim of this in vitro study was to compare the effect of combined chemical and mechanical debr... more The aim of this in vitro study was to compare the effect of combined chemical and mechanical debridement of titanium (Ti) surfaces inoculated with Staphylococcus epidermidis, compared with the effect of chemical debridement alone. Different Ti surfaces were characterized with respect to roughness and subsequently inoculated with S. epidermidis. NaCl (0.9 vol.%), EDTA (12 vol.%), H₂O₂ (3 vol.%) or H₂O₂ + TiO₂ nanoparticles served as chemical debridement agents, while TiBrush was used as the mechanical debridement tool. Safranin staining assessed biomass still attached to surfaces after debridement. Biofilm viability was assessed after re-incubation of the debrided samples. SEM analysis was performed before and after the cleaning process. Surface average roughness (Sa ) of the samples was measured at 2.22 ± 0.19 μm for group A, 0.19 ± 0.02 μm for group B, and 1.99 ± 0.10 μm for group C. When chemical debridement agents were used alone, H₂O₂-containing products were most efficient in reducing the biomass load. The surface roughness did not affect the outcome of chemical debridement. However, when combining chemical and mechanical debridement, a further reduction of biofilm load and viability was observed with best effect on the smoothest surface. Combining H₂O₂-containing chemical agents with mechanical debridement (TiBrush) provided best reduction in biofilm mass and re-growth, when studied in vitro.
Journal of Biomaterials Applications, 2014
The aim of this study was to investigate the effect of TiO2 scaffold (SC) coated with an alginate... more The aim of this study was to investigate the effect of TiO2 scaffold (SC) coated with an alginate hydrogel containing a proline-rich peptide (P2) on osteoblast proliferation and differentiation in vitro. Peptide release was evaluated and a burst release was observed during the first hours of incubation, and then progressively released overtime. No changes were observed in the cytotoxicity after 48 h of seeding MC3T3-E1 cells on the coated and uncoated TiO2 SC. The amount of cells after 7 days was higher on uncoated TiO2 SC than on alginate-coated TiO2 SC, measured by DNA content and scanning electron microscope imaging. In addition, while lower expression of integrin beta1 was detected for alginate-coated TiO2 SC at this time point, similar gene expression was observed for other integrins, fibronectin-1, and several osteoblast differentiation markers. After 21 days, gene expression of integrin beta3, fibronectin-1, osterix, and collagen-I was increased in alginate-coated compared to TiO2 SC. Moreover, increased gene expression of integrin alpha8, bone morphogenetic protein 2, interleukin-6, and collagen-I was found on P2 alginate-coated TiO2 SC compared to alginate-coated TiO2 SC. In conclusion, our results indicate that alginate-coated TiO2 SC can act as a matrix for delivery of proline-rich peptides increasing osteoblast differentiation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Adsorption of biomolecules onto material surfaces involves a potentially complex mechanism where ... more Adsorption of biomolecules onto material surfaces involves a potentially complex mechanism where molecular species interact to varying degrees with a heterogeneous material surface. Surface adsorption studies by atomic force microscopy, sum frequency generation spectroscopy, and solid-state NMR detect the structures and interactions of biomolecular species that are bound to material surfaces, which, in the absence of a solid−liquid interface, do not exchange rapidly between surface-bound forms and free molecular species in bulk solution. Solution NMR has the potential to complement these techniques by detecting and studying transiently bound biomolecules at the liquid−solid interface. Herein, we show that dark-state exchange saturation transfer (DEST) NMR experiments on gel-stabilized TiO 2 nanoparticle (NP) samples detect several forms of biomolecular adsorption onto titanium(IV) oxide surfaces. Specifically, we use the DEST approach to study the interaction of amino acids arginine (Arg), lysine (Lys), leucine (Leu), alanine (Ala), and aspartic acid (Asp) with TiO 2 rutile NP surfaces. Whereas Leu, Ala, and Asp display only a single weakly interacting form in the presence of TiO 2 NPs, Arg and Lys displayed at least two distinct bound forms: a species that is surface bound and retains a degree of reorientational motion and a second more tightly bound form characterized by broadened DEST profiles upon the addition of TiO 2 NPs. Molecular dynamics simulations indicate different surface bound states for both Lys and Arg depending on the degree of TiO 2 surface hydroxylation but only a single bound state for Asp regardless of the degree of surface hydroxylation, in agreement with results obtained from the analysis of DEST profiles.
International Journal of Molecular Sciences
In this study, the effect on osteoclast activity in vitro and in vivo of titanium implants that w... more In this study, the effect on osteoclast activity in vitro and in vivo of titanium implants that were coated with quercitrin was evaluated. Titanium surfaces were covalently coated with the flavonoid quercitrin. The effect of the surfaces on osteoclastogenesis was first tested in vitro on RAW264.7 cells that were supplemented with receptor activator of nuclear factor kappa-B ligand (RANKL) to generate osteoclast-like cells by tartrate-resistant acid phosphatase (TRAP) inmunostaining after five days of culture, and by analysis of the mRNA expression levels of markers related to bone resorption after seven days of culture. A rabbit tibial model was used to evaluate the in vivo biological response to the implant surfaces after eight weeks of healing, analyzing the lactate dehydrogenase (LDH) and the alkaline phosphatase (ALP) activities in the wound fluid that were present at the implant interface and the peri-implant bone mRNA expression levels of several markers related to inflammatio...
Journal of Clinical Periodontology
Bovine xenograft materials, followed by synthetic biomaterials, which unfortunately still lack do... more Bovine xenograft materials, followed by synthetic biomaterials, which unfortunately still lack documented predictability and clinical performance, dominate the market for the cranio-maxillofacial area. In Europe, new stringent regulations are expected to further limit the allograft market in the future. Aim: Within this narrative review, we discuss possible future biomaterials for bone replacement. Scientific Rationale for Study: Although the bone graft (BG) literature is overflooded, only a handful of new BG substitutes are clinically available. Laboratory studies tend to focus on advanced production methods and novel biomaterial features, which can be costly to produce. Practical Implications: In this review, we ask why such a limited number of BGs are clinically available when compared to extensive laboratory studies. We also discuss what features are needed for an ideal BG. Results: We have identified the key properties of current bone substitutes and have provided important information to guide clinical decision-making and generate new perspectives on bone substitutes. Our results indicated that different mechanical and biological properties are needed despite each having a broad spectrum of variations. Conclusions: We foresee bone replacement composite materials with higher levels of bioactivity, providing an appropriate balance between bioabsorption and volume maintenance for achieving ideal bone remodelling.
The present invention relates to the ?eld of terminal ?shing tackle, such as leaders, bait, lures... more The present invention relates to the ?eld of terminal ?shing tackle, such as leaders, bait, lures and/or ?ies, made from natural and/ or synthetic ?bres and coated With a uniform nano-thin metal oxide layer. More particularly, the present invention relates to terminal ?shing tackle that has a hydro phobic, hydrophilic, super hydrophilic, Water sealant, colour introducing, photocatalytic, UV-protecting, anti-microbial, and/ or anti-fouling property, Wherein said property is gained by a coating using advanced methods for atomic layer depo sition, or combinations of atomic layer deposition and addi tional coating on said tackle. In a preferred embodiment, said coating is selected from Carbon, Gold, Palladium, TiO2, Al2O3, SiO2 and combinations thereof. BACKGROUND TO THE INVENTION [0002] There are many different styles of ?shing and many of them involve the use of a line, and a lure, spinner, arti?cial ?y or other attractant. Fly ?shing is a style of ?shing in Which a very light Weight "?y" is attached to the end of a ?shing line. The Word "?y" is used to describe the device that attracts the attention of the ?sh and causes it to strike. This "?y" can be a construction Which is designed to simulate the general shape, colour, siZe, and look of a ?y or other insect or nymph or spaWn or small ?sh Which is naturally occurring in the ?sh's environment.