Mika Ishioka - Academia.edu (original) (raw)

Papers by Mika Ishioka

Acta Odontologica Scandinavica, 2012

Association between perceived chewing ability and oral health-related quality of life in partiall... more Association between perceived chewing ability and oral health-related quality of life in partially dentate patients

Dentistry, 2012

Bone regeneration is a complex, well-coordinated physiological process. Large quantities of bone ... more Bone regeneration is a complex, well-coordinated physiological process. Large quantities of bone regeneration are often required for craniofacial skeletal reconstruction of large bone defects created by trauma, tumor resection, infection, and skeletal abnormalities. Over the last two decades, a tissue engineering and regeneration approach has been developed as an alternative to conventional surgical treatments using bone grafts. Tissue engineering methods have several advantages including the potential to regenerate bone with natural form and function. This review presents several key elements of tissue engineering for craniofacial bone: the signaling molecules (proteins and genes); scaffolds or supporting matrices; and cells. Furthermore, the advantages, challenges, and risks related with each element will be discussed.

Journal of Physics: Condensed Matter, 2010

The electronic structure of γ phase in the system Mg(17)Al(12) containing 58 atoms per unit cell ... more The electronic structure of γ phase in the system Mg(17)Al(12) containing 58 atoms per unit cell with space group I43m has been calculated by using the WIEN2k-FLAPW program package. A pseudogap is found across the Fermi level. The FLAPW-Fourier spectra at the symmetry points N and Γ of the bcc Brillouin zone revealed that electronic states across the Fermi level at these symmetry points are dominated by |G|(2) = 26 and 24 states corresponding to centers of {510} + {431} and {422} zone planes, respectively. The 1253-wave nearly-free-electron (NFE) band calculations identified that a combination of the two Fermi surface-Brillouin-zone (FsBz) interactions associated with |G|(2) = 26 and 24 account well for the observed DOS pseudogap in γ-Mg(17)Al(12), most likely leading to the stabilization of this complex metallic compound. The β-Al(3)Mg(2) containing 1178 atoms per cubic unit cell is suggested to be stabilized by satisfying the Hume-Rothery matching condition expressed in terms of e/uc, the number of electrons per unit cell, versus critical |G|(2). A critical |G|(2) is predicted to be 200 in β-Al(3)Mg(2), which results in 84 Brillouin zone planes interacting almost simultaneously with a more or less spherical Fermi surface.

Journal of Oral Rehabilitation, 2008

To report about the feasibility of oral health-related quality of life assessment using two short... more To report about the feasibility of oral health-related quality of life assessment using two short forms of the Oral Health Impact Profile - OHIP-J14 and OHIP-J5 - in prosthodontic patients. Using the item pool of the Japanese version of the OHIP, two short forms based on a 14-item English-language version and a 5-item German-language questionnaire were derived. To test construct validity, the associations between summary scores of two short versions and self-reported oral health and self-reported denture quality have been investigated. Responsiveness was tested in 30 patients treated for their removable partial denture. Test-retest reliability using a time interval of 2 weeks and internal consistency were also tested. Associations between the two short form summary scores and self-reported oral health and denture quality supported construct validity of the instruments. Acceptable reliability for OHIP-J14 and OHIP-J5 was indicated by intra-class correlation coefficients of 0.73 and 0.75 (test-retest reliability) and CRONBACH'S alpha of 0.94 and 0.81 (internal consistency) respectively. Responsiveness was sufficient for OHIP-J14 and OHIP-J5 indicated by 'medium' effect sizes (0.50 and 0.57 respectively). In addition to sufficient discriminative psychometric properties, the ability to measure change of perceived oral health make OHIP-J14 and OHIP-J5 suitable for outcomes research.

Journal of Dental Research, 2008

The impact of oral disorders and interventions on individuals’ perceived oral health and oral-hea... more The impact of oral disorders and interventions on individuals’ perceived oral health and oral-health-related quality of life (OHRQoL) is being increasingly recognized as an important health component. This study examined the association between denture quality and OHRQoL in individuals wearing removable partial dentures (RPDs). The study participants were 245 consecutive patients (mean age: 63.3 ± 8.7 yrs) at a university-based prosthodontic clinic who wore RPDs for more than one month. RPD quality and OHRQoL were determined by means of a 100-mm visual analog scale (VAS) and the 49-item Oral Health Impact Profile-Japanese version (OHIP-J49), respectively. Linear regression analysis between RPD quality and OHRQoL revealed that a 10-mm VAS increase in RPD quality rating was related to −2.8 OHIP-J49 units (95% confidence interval: −4.5 to −1.1, p = 0.001), which represents an improvement in OHRQoL. The results suggest that RPD quality influences individuals’ OHRQoL to a clinically sign...

Health and Quality of Life Outcomes, 2010

Background One of the most immediate and important functional consequences of many oral disorders... more Background One of the most immediate and important functional consequences of many oral disorders is a reduction in chewing ability. The ability to chew is not only an important dimension of oral health, but is increasingly recognized as being associated with general health status. Whether perceived chewing ability and oral health-related quality of life (OHRQoL) are correlated to a similar degree in patient populations has been less investigated. The aim of this study was to examine whether perceived chewing ability was related to OHRQoL in partially dentate patients. Methods Consecutive partially dentate patients (N = 489) without signs or symptoms of acute oral disease at Tokyo Medical and Dental University's Prosthodontic Clinic participated in the study (mean age 63.0 ± 11.5, 71.2% female). A 20-item chewing function questionnaire (score range 0 to 20) was used to assess perceived chewing ability, with higher scores indicating better chewing ability. The 14-item Oral Health...

BMC Oral Health, 2009

Background: The aim of this study was to investigate the dimensionality, reliability, and validit... more Background: The aim of this study was to investigate the dimensionality, reliability, and validity of an alternate version of the chewing function questionnaire in partially dentate patients in Japan. Methods: Subjects were partially dentate patients who attended the prosthodontic clinic at Tokyo Medical and Dental University (N = 491, 71% women, mean age (± SD): 63.0 ± 11.5 years). The questionnaire asked each subject to rate his or her ability to chew 20 common Japanese foods. For each individual, responses were combined to yield a chewing function summary score, with higher scores indicating better self-reported chewing ability. We used exploratory factor analysis to investigate the scores' dimensionality. For validity assessment, we computed the correlations between the chewing function score and oral health-related quality of life (OHRQoL, as measured by the Japanese 14-item Oral Health Impact Profile (OHIP-14)) Internal consistency of scores and test-retest reliability were investigated by asking a subset of subjects (N = 62) to complete the questionnaire twice, 2 weeks apart. Results: Exploratory factor analysis provided some evidence that self-reported chewing ability can be characterized by a summary score as the original authors suggest. Support for the validity of chewing function scores using the alternate version of the questionnaire was derived from correlations with OHIP-14 scores (r =-0.46, 95% confidence interval (CI):-0.53 to-0.39); thus, better chewing ability was associated with less impaired OHRQoL. Internal consistency was 'satisfactory,' with a Cronbach's alpha of 0.90 (lower limit of 95% CI: 0.89). The test-retest reliability was 'good,' with an intraclass correlation coefficient of 0.69 (95% CI: 0.56 to 0.82). Conclusion: The alternate version of the chewing function questionnaire can be used as a standalone instrument because of the demonstrated reliability and validity of scores obtained using the questionnaire in partially dentate patients.

Biomaterials, 2014

Regenerative procedures using barrier membrane technology are presently well established in perio... more Regenerative procedures using barrier membrane technology are presently well established in periodontal/endodontic surgery. The objective of this study was to compare the subsequent effects of the released platelet-derived growth factor (PDGF) and growth/differentiation factor 5 (GDF-5) from collagen membranes (CMs) on bone regeneration in vitro and in vivo. In vitro studies were conducted using MC3T3-E1 mouse preosteoblasts cultured with or without factors. Cell viability, cell proliferation, alkaline phosphatase (ALP) activity and bone marker gene expression were then measured. In vivo studies were conducted by placing CMs with low or high dose PDGF or GDF-5 in rat mandibular defects. At 4 weeks after surgery new bone formation was measured using mCT and histological analysis. The results of in vitro studies showed that CM/GDF-5 significantly increased ALP and cell proliferation activities without cytotoxicity in MC3T3-E1 cells when compared to CM/PDGF or CM alone. Gene expression analysis revealed that Runx2 and Osteocalcin were significantly increased in CM/GDF-5 compared to CM/ PDGF or control. Quantitative and qualitative mCT and histological analysis for new bone formation revealed that although CM/PDGF significantly enhanced bone regeneration compared to CM alone or control, CM/GDF-5 significantly accelerated bone regeneration to an even greater extent than CM/PDGF. The results also showed that GDF-5 induced new bone formation in a dose-dependent manner. These results suggest that this strategy, using a CM carrying GDF-5, might lead to an improvement in the current clinical treatment of bone defects for periodontal and implant therapy.

Journal of Oral Rehabilitation, 2007

The objective of the study was to develop a Japanese version of the Oral Health Impact Profile (O... more The objective of the study was to develop a Japanese version of the Oral Health Impact Profile (OHIP). The original 49 items were translated using a forward-backward method following accepted cultural adaptation guidelines. A de novo development of Japanese items was conducted to establish content validity. The associations between the OHIP summary score and self-reported oral health (n = 220) and self-reported denture quality (n = 155) were investigated for construct validity. The association between the OHIP summary score and six oral conditions (n = 227) were also tested. The responsiveness of the instrument was established by comparing the score before and after using newly fabricated removable partial dentures (n = 30). The test-retest reliability (n = 37) and internal consistency (n = 251) were also calculated. After the de novo development, five new items were added to the OHIP. The priori hypothesized associations between the OHIP score and oral health conditions were confirmed (P < 0.001). The change in the OHIP scores from 63.6 to 40.6 (P < 0.001) supports the responsiveness of the instrument. Intra-class correlation coefficients of 0.81 and Cronbach's alpha of 0.98 indicate high test-retest reliability and internal consistency of the instrument's summary score. Sufficient discriminative and evaluative psychometric properties of the currently developed Japanese version of the OHIP in typical target populations make the instrument suitable for assessing the oral health-related quality of life in cross-sectional as well as longitudinal studies.

Biotechnology Letters, Feb 27, 2014

A combination of modified HIV-1 Tat (mTat) peptide and cationic lipids, FuGENE HD (FH), dramatica... more A combination of modified HIV-1 Tat (mTat) peptide and cationic lipids, FuGENE HD (FH), dramatically enhanced transfection efficiency across a range of cell lines when compared to mTat or FH alone (Biomaterials 35:1705-1715 2014). The efficiency of this Tat peptide combination was significantly higher than many commercial non-viral vectors. In this present study, we tested the feasibility of this nonviral vector, mTat/FH, in vivo using plasmid DNA encoding a luciferase gene. The results of the in vivo studies showed that animals administered mTat/FH/ DNA intramuscularly had significantly higher and longer luciferase expression (&7 months) than those with mTat/DNA, FH/DNA, or DNA alone. Histological evaluation showed little immune response in the muscles, livers, and kidneys of mice administered with the mTat/FH. The combination of mTat with FH could significantly improve transfection efficiency, expanding the potential use of non-viral gene vectors in vivo.

Biomaterials

Polyethylenimine (PEI), a cationic polymer, has been widely studied and shown great promise as an... more Polyethylenimine (PEI), a cationic polymer, has been widely studied and shown great promise as an efficient gene delivery vehicle. Likewise, the HIV-1 Tat peptide, a cell-permeable peptide, has been successfully used for intracellular gene delivery. To improve the favorable properties of these two vectors, we combine PEI with the modified Tat peptide sequence bearing histidine and cysteine residues (mTat). In vitro mTat/PEI-mediated transfection was evaluated by luciferase expression plasmid in two cell types. mTat/PEI produced significant improvement (≈5-fold) in transfection efficiency of both cell lines with little cytotoxicity when compared to mTat alone, PEI alone, or four commercial reagents. The particle size of mTat/PEI/DNA complex was significantly smaller than mTat or PEI alone, and it was correlated with higher transfection efficiency. Filipin III, an inhibitor of caveolae-mediated endocytosis, significantly inhibited mTat/PEI transfection. In contrast, chlorpromazine, an...

Regenerative procedures using barrier membrane technology are presently well established in perio... more Regenerative procedures using barrier membrane technology are presently well established in periodontal/endodontic surgery. The objective of this study was to compare the subsequent effects of the released platelet-derived growth factor (PDGF) and growth/differentiation factor 5 (GDF-5) from collagen membranes (CMs) on bone regeneration in vitro and in vivo. In vitro studies were conducted using MC3T3-E1 mouse preosteoblasts cultured with or without factors. Cell viability, cell proliferation, alkaline phosphatase (ALP) activity and bone marker gene expression were then measured. In vivo studies were conducted by placing CMs with low or high dose PDGF or GDF-5 in rat mandibular defects. At 4 weeks after surgery new bone formation was measured using mCT and histological analysis. The results of in vitro studies showed that CM/GDF-5 significantly increased ALP and cell proliferation activities without cytotoxicity in MC3T3-E1 cells when compared to CM/PDGF or CM alone. Gene expression analysis revealed that Runx2 and Osteocalcin were significantly increased in CM/GDF-5 compared to CM/ PDGF or control. Quantitative and qualitative mCT and histological analysis for new bone formation revealed that although CM/PDGF significantly enhanced bone regeneration compared to CM alone or control, CM/GDF-5 significantly accelerated bone regeneration to an even greater extent than CM/PDGF. The results also showed that GDF-5 induced new bone formation in a dose-dependent manner. These results suggest that this strategy, using a CM carrying GDF-5, might lead to an improvement in the current clinical treatment of bone defects for periodontal and implant therapy.

Acta Odontologica Scandinavica, 2012

Association between perceived chewing ability and oral health-related quality of life in partiall... more Association between perceived chewing ability and oral health-related quality of life in partially dentate patients

Dentistry, 2012

Bone regeneration is a complex, well-coordinated physiological process. Large quantities of bone ... more Bone regeneration is a complex, well-coordinated physiological process. Large quantities of bone regeneration are often required for craniofacial skeletal reconstruction of large bone defects created by trauma, tumor resection, infection, and skeletal abnormalities. Over the last two decades, a tissue engineering and regeneration approach has been developed as an alternative to conventional surgical treatments using bone grafts. Tissue engineering methods have several advantages including the potential to regenerate bone with natural form and function. This review presents several key elements of tissue engineering for craniofacial bone: the signaling molecules (proteins and genes); scaffolds or supporting matrices; and cells. Furthermore, the advantages, challenges, and risks related with each element will be discussed.

Journal of Physics: Condensed Matter, 2010

The electronic structure of γ phase in the system Mg(17)Al(12) containing 58 atoms per unit cell ... more The electronic structure of γ phase in the system Mg(17)Al(12) containing 58 atoms per unit cell with space group I43m has been calculated by using the WIEN2k-FLAPW program package. A pseudogap is found across the Fermi level. The FLAPW-Fourier spectra at the symmetry points N and Γ of the bcc Brillouin zone revealed that electronic states across the Fermi level at these symmetry points are dominated by |G|(2) = 26 and 24 states corresponding to centers of {510} + {431} and {422} zone planes, respectively. The 1253-wave nearly-free-electron (NFE) band calculations identified that a combination of the two Fermi surface-Brillouin-zone (FsBz) interactions associated with |G|(2) = 26 and 24 account well for the observed DOS pseudogap in γ-Mg(17)Al(12), most likely leading to the stabilization of this complex metallic compound. The β-Al(3)Mg(2) containing 1178 atoms per cubic unit cell is suggested to be stabilized by satisfying the Hume-Rothery matching condition expressed in terms of e/uc, the number of electrons per unit cell, versus critical |G|(2). A critical |G|(2) is predicted to be 200 in β-Al(3)Mg(2), which results in 84 Brillouin zone planes interacting almost simultaneously with a more or less spherical Fermi surface.

Journal of Oral Rehabilitation, 2008

To report about the feasibility of oral health-related quality of life assessment using two short... more To report about the feasibility of oral health-related quality of life assessment using two short forms of the Oral Health Impact Profile - OHIP-J14 and OHIP-J5 - in prosthodontic patients. Using the item pool of the Japanese version of the OHIP, two short forms based on a 14-item English-language version and a 5-item German-language questionnaire were derived. To test construct validity, the associations between summary scores of two short versions and self-reported oral health and self-reported denture quality have been investigated. Responsiveness was tested in 30 patients treated for their removable partial denture. Test-retest reliability using a time interval of 2 weeks and internal consistency were also tested. Associations between the two short form summary scores and self-reported oral health and denture quality supported construct validity of the instruments. Acceptable reliability for OHIP-J14 and OHIP-J5 was indicated by intra-class correlation coefficients of 0.73 and 0.75 (test-retest reliability) and CRONBACH'S alpha of 0.94 and 0.81 (internal consistency) respectively. Responsiveness was sufficient for OHIP-J14 and OHIP-J5 indicated by 'medium' effect sizes (0.50 and 0.57 respectively). In addition to sufficient discriminative psychometric properties, the ability to measure change of perceived oral health make OHIP-J14 and OHIP-J5 suitable for outcomes research.

Journal of Dental Research, 2008

The impact of oral disorders and interventions on individuals’ perceived oral health and oral-hea... more The impact of oral disorders and interventions on individuals’ perceived oral health and oral-health-related quality of life (OHRQoL) is being increasingly recognized as an important health component. This study examined the association between denture quality and OHRQoL in individuals wearing removable partial dentures (RPDs). The study participants were 245 consecutive patients (mean age: 63.3 ± 8.7 yrs) at a university-based prosthodontic clinic who wore RPDs for more than one month. RPD quality and OHRQoL were determined by means of a 100-mm visual analog scale (VAS) and the 49-item Oral Health Impact Profile-Japanese version (OHIP-J49), respectively. Linear regression analysis between RPD quality and OHRQoL revealed that a 10-mm VAS increase in RPD quality rating was related to −2.8 OHIP-J49 units (95% confidence interval: −4.5 to −1.1, p = 0.001), which represents an improvement in OHRQoL. The results suggest that RPD quality influences individuals’ OHRQoL to a clinically sign...

Health and Quality of Life Outcomes, 2010

Background One of the most immediate and important functional consequences of many oral disorders... more Background One of the most immediate and important functional consequences of many oral disorders is a reduction in chewing ability. The ability to chew is not only an important dimension of oral health, but is increasingly recognized as being associated with general health status. Whether perceived chewing ability and oral health-related quality of life (OHRQoL) are correlated to a similar degree in patient populations has been less investigated. The aim of this study was to examine whether perceived chewing ability was related to OHRQoL in partially dentate patients. Methods Consecutive partially dentate patients (N = 489) without signs or symptoms of acute oral disease at Tokyo Medical and Dental University's Prosthodontic Clinic participated in the study (mean age 63.0 ± 11.5, 71.2% female). A 20-item chewing function questionnaire (score range 0 to 20) was used to assess perceived chewing ability, with higher scores indicating better chewing ability. The 14-item Oral Health...

BMC Oral Health, 2009

Background: The aim of this study was to investigate the dimensionality, reliability, and validit... more Background: The aim of this study was to investigate the dimensionality, reliability, and validity of an alternate version of the chewing function questionnaire in partially dentate patients in Japan. Methods: Subjects were partially dentate patients who attended the prosthodontic clinic at Tokyo Medical and Dental University (N = 491, 71% women, mean age (± SD): 63.0 ± 11.5 years). The questionnaire asked each subject to rate his or her ability to chew 20 common Japanese foods. For each individual, responses were combined to yield a chewing function summary score, with higher scores indicating better self-reported chewing ability. We used exploratory factor analysis to investigate the scores' dimensionality. For validity assessment, we computed the correlations between the chewing function score and oral health-related quality of life (OHRQoL, as measured by the Japanese 14-item Oral Health Impact Profile (OHIP-14)) Internal consistency of scores and test-retest reliability were investigated by asking a subset of subjects (N = 62) to complete the questionnaire twice, 2 weeks apart. Results: Exploratory factor analysis provided some evidence that self-reported chewing ability can be characterized by a summary score as the original authors suggest. Support for the validity of chewing function scores using the alternate version of the questionnaire was derived from correlations with OHIP-14 scores (r =-0.46, 95% confidence interval (CI):-0.53 to-0.39); thus, better chewing ability was associated with less impaired OHRQoL. Internal consistency was 'satisfactory,' with a Cronbach's alpha of 0.90 (lower limit of 95% CI: 0.89). The test-retest reliability was 'good,' with an intraclass correlation coefficient of 0.69 (95% CI: 0.56 to 0.82). Conclusion: The alternate version of the chewing function questionnaire can be used as a standalone instrument because of the demonstrated reliability and validity of scores obtained using the questionnaire in partially dentate patients.

Biomaterials, 2014

Regenerative procedures using barrier membrane technology are presently well established in perio... more Regenerative procedures using barrier membrane technology are presently well established in periodontal/endodontic surgery. The objective of this study was to compare the subsequent effects of the released platelet-derived growth factor (PDGF) and growth/differentiation factor 5 (GDF-5) from collagen membranes (CMs) on bone regeneration in vitro and in vivo. In vitro studies were conducted using MC3T3-E1 mouse preosteoblasts cultured with or without factors. Cell viability, cell proliferation, alkaline phosphatase (ALP) activity and bone marker gene expression were then measured. In vivo studies were conducted by placing CMs with low or high dose PDGF or GDF-5 in rat mandibular defects. At 4 weeks after surgery new bone formation was measured using mCT and histological analysis. The results of in vitro studies showed that CM/GDF-5 significantly increased ALP and cell proliferation activities without cytotoxicity in MC3T3-E1 cells when compared to CM/PDGF or CM alone. Gene expression analysis revealed that Runx2 and Osteocalcin were significantly increased in CM/GDF-5 compared to CM/ PDGF or control. Quantitative and qualitative mCT and histological analysis for new bone formation revealed that although CM/PDGF significantly enhanced bone regeneration compared to CM alone or control, CM/GDF-5 significantly accelerated bone regeneration to an even greater extent than CM/PDGF. The results also showed that GDF-5 induced new bone formation in a dose-dependent manner. These results suggest that this strategy, using a CM carrying GDF-5, might lead to an improvement in the current clinical treatment of bone defects for periodontal and implant therapy.

Journal of Oral Rehabilitation, 2007

The objective of the study was to develop a Japanese version of the Oral Health Impact Profile (O... more The objective of the study was to develop a Japanese version of the Oral Health Impact Profile (OHIP). The original 49 items were translated using a forward-backward method following accepted cultural adaptation guidelines. A de novo development of Japanese items was conducted to establish content validity. The associations between the OHIP summary score and self-reported oral health (n = 220) and self-reported denture quality (n = 155) were investigated for construct validity. The association between the OHIP summary score and six oral conditions (n = 227) were also tested. The responsiveness of the instrument was established by comparing the score before and after using newly fabricated removable partial dentures (n = 30). The test-retest reliability (n = 37) and internal consistency (n = 251) were also calculated. After the de novo development, five new items were added to the OHIP. The priori hypothesized associations between the OHIP score and oral health conditions were confirmed (P < 0.001). The change in the OHIP scores from 63.6 to 40.6 (P < 0.001) supports the responsiveness of the instrument. Intra-class correlation coefficients of 0.81 and Cronbach's alpha of 0.98 indicate high test-retest reliability and internal consistency of the instrument's summary score. Sufficient discriminative and evaluative psychometric properties of the currently developed Japanese version of the OHIP in typical target populations make the instrument suitable for assessing the oral health-related quality of life in cross-sectional as well as longitudinal studies.

Biotechnology Letters, Feb 27, 2014

A combination of modified HIV-1 Tat (mTat) peptide and cationic lipids, FuGENE HD (FH), dramatica... more A combination of modified HIV-1 Tat (mTat) peptide and cationic lipids, FuGENE HD (FH), dramatically enhanced transfection efficiency across a range of cell lines when compared to mTat or FH alone (Biomaterials 35:1705-1715 2014). The efficiency of this Tat peptide combination was significantly higher than many commercial non-viral vectors. In this present study, we tested the feasibility of this nonviral vector, mTat/FH, in vivo using plasmid DNA encoding a luciferase gene. The results of the in vivo studies showed that animals administered mTat/FH/ DNA intramuscularly had significantly higher and longer luciferase expression (&7 months) than those with mTat/DNA, FH/DNA, or DNA alone. Histological evaluation showed little immune response in the muscles, livers, and kidneys of mice administered with the mTat/FH. The combination of mTat with FH could significantly improve transfection efficiency, expanding the potential use of non-viral gene vectors in vivo.

Biomaterials

Polyethylenimine (PEI), a cationic polymer, has been widely studied and shown great promise as an... more Polyethylenimine (PEI), a cationic polymer, has been widely studied and shown great promise as an efficient gene delivery vehicle. Likewise, the HIV-1 Tat peptide, a cell-permeable peptide, has been successfully used for intracellular gene delivery. To improve the favorable properties of these two vectors, we combine PEI with the modified Tat peptide sequence bearing histidine and cysteine residues (mTat). In vitro mTat/PEI-mediated transfection was evaluated by luciferase expression plasmid in two cell types. mTat/PEI produced significant improvement (≈5-fold) in transfection efficiency of both cell lines with little cytotoxicity when compared to mTat alone, PEI alone, or four commercial reagents. The particle size of mTat/PEI/DNA complex was significantly smaller than mTat or PEI alone, and it was correlated with higher transfection efficiency. Filipin III, an inhibitor of caveolae-mediated endocytosis, significantly inhibited mTat/PEI transfection. In contrast, chlorpromazine, an...

Regenerative procedures using barrier membrane technology are presently well established in perio... more Regenerative procedures using barrier membrane technology are presently well established in periodontal/endodontic surgery. The objective of this study was to compare the subsequent effects of the released platelet-derived growth factor (PDGF) and growth/differentiation factor 5 (GDF-5) from collagen membranes (CMs) on bone regeneration in vitro and in vivo. In vitro studies were conducted using MC3T3-E1 mouse preosteoblasts cultured with or without factors. Cell viability, cell proliferation, alkaline phosphatase (ALP) activity and bone marker gene expression were then measured. In vivo studies were conducted by placing CMs with low or high dose PDGF or GDF-5 in rat mandibular defects. At 4 weeks after surgery new bone formation was measured using mCT and histological analysis. The results of in vitro studies showed that CM/GDF-5 significantly increased ALP and cell proliferation activities without cytotoxicity in MC3T3-E1 cells when compared to CM/PDGF or CM alone. Gene expression analysis revealed that Runx2 and Osteocalcin were significantly increased in CM/GDF-5 compared to CM/ PDGF or control. Quantitative and qualitative mCT and histological analysis for new bone formation revealed that although CM/PDGF significantly enhanced bone regeneration compared to CM alone or control, CM/GDF-5 significantly accelerated bone regeneration to an even greater extent than CM/PDGF. The results also showed that GDF-5 induced new bone formation in a dose-dependent manner. These results suggest that this strategy, using a CM carrying GDF-5, might lead to an improvement in the current clinical treatment of bone defects for periodontal and implant therapy.