PubMed | Dankook University, Oxford UCL Center for the Advancement of Sustainable Medical Innovation and, UCL Eastman Dental Institute, Massachusetts Institute of Technology and 15 more.
Type: Journal Article | Journal: Stem cells translational medicine | Year: 2015
There is a need for physical standards (reference materials) to ensure both reproducibility and consistency in the production of somatic cell types from human pluripotent stem cell (hPSC) sources. We have outlined the need for reference materials (RMs) in relation to the unique properties and concerns surrounding hPSC-derived products and suggest in-house approaches to RM generation relevant to basic research, drug screening, and therapeutic applications. hPSCs have an unparalleled potential as a source of somatic cells for drug screening, disease modeling, and therapeutic application. Undefined variation and product variability after differentiation to the lineage or cell type of interest impede efficient translation and can obscure the evaluation of clinical safety and efficacy. Moreover, in the absence of a consistent population, data generated from in vitro studies could be unreliable and irreproducible. Efforts to devise approaches and tools that facilitate improved consistency of hPSC-derived products, both as development tools and therapeutic products, will aid translation. Standards exist in both written and physical form; however, because many unknown factors persist in the field, premature written standards could inhibit rather than promote innovation and translation. We focused on the derivation of physical standard RMs. We outline the need for RMs and assess the approaches to in-house RM generation for hPSC-derived products, a critical tool for the analysis and control of product variation that can be applied by researchers and developers. We then explore potential routes for the generation of RMs, including both cellular and noncellular materials and novel methods that might provide valuable tools to measure and account for variation. Multiparametric techniques to identify signatures for therapeutically relevant cell types, such as neurons and cardiomyocytes that can be derived from hPSCs, would be of significant utility, although physical RMs will be required for clinical purposes.
Watson E.K.,UCL Eastman Dental Institute |
Moles D.R.,Peninsula Dental School |
Kumar N.,UCL Eastman Dental Institute |
Porter S.R.,UCL Eastman Dental Institute
British Dental Journal | Year: 2010
Aim: There is little information available concerning the impact of visual impairment upon oral health. The present study sought to identify the oral health and experiences of adults with a visual impairment together with the nature, source and access to oral health information. In addition the study evaluated the oral health status of a group of individuals with a visual impairment with respect to oral health markers, treatment choice and attendance patterns in comparison to a reference group from the general population in the United Kingdom. Method: One hundred adults with a visual impairment were examined and completed a questionnaire concerning their experience of oral health care and available information sources. The information collected was directly compared with data from the Adult Dental Health Survey 1998 for the south region of England. Results: The present group of individuals with a visual impairment had better oral hygiene practices, and similar levels of oral hygiene and hard tissue disease to those of a comparable group of the Adult Dental Health Survey 1998 (ADHS 1998). However 24% of those with a visual impairment were not registered with a dentist and 26% of the patients wished for appropriate information concerning oral health care. Conclusions: There is a need to develop oral health promotion that ensures patients with a visual impairment have appropriate information regarding oral health care and its provision. © 2010 Macmillan Publishers Limited. All rights reserved.
Shah R.,UCL Eastman Dental Institute |
Ready D.,Eastman Dental Hospital |
Knowles J.C.,UCL Eastman Dental Institute |
Knowles J.C.,Dankook University |
And 3 more authors.
Journal of Tissue Engineering and Regenerative Medicine | Year: 2014
Tissue engineering has the potential to overcome limitations associated with current management of skeletal muscle defects. This study aimed to sequentially identify a degradable phosphate glass scaffold for the restoration of muscle defects. A series of glass compositions were investigated for the potential to promote bacterial growth. Thereafter, the response of human craniofacial muscle-derived cells was determined. Glass compositions containing Fe4- and 5mol% did not promote greater Staphylococcus aureus and Staphylococcus epidermidis growth compared to the control (p>0.05). Following confirmation of myogenicity, further studies assessed the biocompatibility of glasses containing Fe5 mol%. Cells seeded on collagen-coated disks demonstrated comparable cellular metabolic activity to control. Upregulation of genes encoding for myogenic regulatory factors (MRFs) confirmed myofibre formation and there was expression of developmental MYH genes. The use of 3-D aligned fibre scaffolds supported unidirectional cell alignment and upregulation of MRF and developmental MYH genes. Compared to the 2-D disks, there was also expression of MYH2 and MYH7 genes, indicating further myofibre maturation on the 3-D scaffolds and confirming the importance of key biophysical cues. © 2012 John Wiley & Sons, Ltd.
Aljabo A.,UCL Eastman Dental Institute |
Xia W.,UCL Eastman Dental Institute |
Liaqat S.,UCL Eastman Dental Institute |
Khan M.A.,UCL Eastman Dental Institute |
And 3 more authors.
Dental Materials | Year: 2015
Objectives Cure, volumetric changes and mechanical properties were assessed for new dental composites containing chlorhexidine (CHX) and reactive calcium phosphate-containing (CaP) to reduce recurrent caries. Methods 20 wt.% of light curable urethane dimethacrylate based liquid was mixed with 80 wt.% glass filler containing 10 wt.% CHX and 0-40 wt.% CaP. Conversion versus depth with 20 or 40 s light exposure was assessed by FTIR. Solidification depth and polymerization shrinkage were determined using ISO 4049 and 17304, respectively. Subsequent volume expansion and biaxial flexural strength and modulus change upon water immersion were determined over 4 weeks. Hydroxyapatite precipitation in simulated body fluid was assessed at 1 week. Results Conversion decreased linearly with both depth and CaP content. Average solidification depths were 4.5, 3.9, 3.3, 2.9 and 5.0 with 0, 10, 20, and 40% CaP and a commercial composite, Z250, respectively. Conversions at these depths were 53 ± 2% for experimental materials but with Z250 only 32%. With Z250 more than 50% conversion was achieved only below 1.1 mm. Shrinkage was 3% and 2.5% for experimental materials and Z250, respectively. Early water sorption increased linearly, whilst strength and modulus decreased exponentially to final values when plotted versus square root of time. Maximum volumetric expansion increased linearly with CaP rise and balanced shrinkage at 10-20 wt.% CaP. Strength and modulus for Z250 decreased from 191 to 158 MPa and 3.2 to 2.5 GPa. Experimental composites initial strength and modulus decreased linearly from 169 to 139 MPa and 5.8 to 3.8 GPa with increasing CaP. Extrapolated final values decreased from 156 to 84 MPa and 4.1 to 1.7 GPa. All materials containing CaP promoted hydroxyapatite precipitation. Significance The lower surface of composite restorations should both be solid and have greater than 50% conversion. The results, therefore, suggest the experimental composite may be placed in much thicker layers than Z250 and have reduced unbounded cytotoxic monomer. Experimental materials with 10-20 wt.% additionally have volumetric expansion to compensate shrinkage, antibacterial and re-mineralizing components and competitive mechanical properties. © 2015 Academy of Dental Materials.
PubMed | UCL Eastman Dental Institute
Type: Journal Article | Journal: Journal of tissue engineering and regenerative medicine | Year: 2014
Tissue engineering has the potential to overcome limitations associated with current management of skeletal muscle defects. This study aimed to sequentially identify a degradable phosphate glass scaffold for the restoration of muscle defects. A series of glass compositions were investigated for the potential to promote bacterial growth. Thereafter, the response of human craniofacial muscle-derived cells was determined. Glass compositions containing Fe4- and 5 mol% did not promote greater Staphylococcus aureus and Staphylococcus epidermidis growth compared to the control (p > 0.05). Following confirmation of myogenicity, further studies assessed the biocompatibility of glasses containing Fe5 mol%. Cells seeded on collagen-coated disks demonstrated comparable cellular metabolic activity to control. Upregulation of genes encoding for myogenic regulatory factors (MRFs) confirmed myofibre formation and there was expression of developmental MYH genes. The use of 3-D aligned fibre scaffolds supported unidirectional cell alignment and upregulation of MRF and developmental MYH genes. Compared to the 2-D disks, there was also expression of MYH2 and MYH7 genes, indicating further myofibre maturation on the 3-D scaffolds and confirming the importance of key biophysical cues.
PubMed | UCL Eastman Dental Institute
Type: Journal Article | Journal: British dental journal | Year: 2015
This paper re-visits the need for patients or their carers to maintain as low a level of denture biofilm as possible. It notes that the handling of dentures is unpleasant to carers and suggests a method of reducing this contact to a minimum but yet allow efficient cleaning by means of brushing. It also highlights the potential damage that can occur due to mishandling or accident. The denture box acts as a safe storage unit and finally, it suggests that its footprint allows accurate recovery in an institution where dentures can be inadvertently mingled.
PubMed | UCL Eastman Dental Institute
Type: Journal Article | Journal: European journal of orthodontics | Year: 2011
The root of the third permanent molar is the only dental structure that continues development after completion of growth of the second permanent molar. It is claimed that the lack of a clearly defined end point for completion of growth of the third permanent molar means that this tooth cannot be used for dental age assessment. The aim of this study was to estimate the mean age of attainment of the four stages (E, F, G, and H) of root development of the third molar. The way in which the end point of completion of stage H can be identified is described. A total of 1223 dental panoramic tomographs (DPTs) available in the archives of the Eastman Dental Hospital, London, were used for this study. The ages of the subjects ranged from 12.6 to 24.9 years with 63 per cent of the sample being female. Demirjans tooth development stages (TDSs), for the first and second molars, were applied to the third molars by a single examiner. For each of stages E, F, and G and for stage H censored data, the mean ages of the males and females were compared, separately within each tooth morphology type using the two sample t-test (P < 0.01). The same test was used to compare the mean ages of the upper and lower third molars on each side, separately for each gender. The mean age of attainment and the 99 per cent confidence interval (CI) for each TDS were calculated for each third molar. The final stage H data were appropriately censored to exclude data above the age of completion of root growth. The results showed that, for each gender, the age in years at which individuals attained each of the four TDSs was approximately normally distributed. The mean age for appropriately censored data was always lower than the corresponding mean age of the inappropriately censored data for stage H (male UR8 19.57, UL8 19.53, LL8 19.91, and LR8 20.02 and female UR8 20.08, UL8 20.13, LL8 20.78, and LR8 20.70). This inappropriately censored data overestimated the mean age for stage H. The appropriately censored data for the TDSs of the third molar may be used to estimate the age of adolescents and emerging adults assuming average growth and development and recent attainment of stage H.
PubMed | Royal Free Hospital, University College London and UCL Eastman Dental Institute
Type: | Journal: International journal of nanomedicine | Year: 2017
Scleroderma (or systemic sclerosis, SSc) is a disease caused by excess crosslinking of collagen. The skin stiffens and becomes painful, while internally, organ function can be compromised by the less elastic collagen. Diagnosis of SSc is often only possible in advanced cases by which treatment time is limited. A more detailed analysis of SSc may provide better future treatment options and information of disease progression. Recently, the histological stain picrosirius red showing collagen register has been combined with atomic force microscopy (AFM) to study SSc. Skin from healthy individuals and SSc patients was biopsied, stained and studied using AFM. By investigating the crosslinking of collagen at a smaller hierarchical stage, the effects of SSc were more pronounced. Changes in morphology and Youngs elastic modulus were observed and quantified; giving rise to a novel technique, we have termed quantitative nanohistology. An increase in nanoscale stiffness in the collagen for SSc compared with healthy individuals was seen by a significant increase in the Youngs modulus profile for the collagen. These markers of stiffer collagen in SSc are similar to the symptoms experienced by patients, giving additional hope that in the future, nanohistology using AFM can be readily applied as a clinical tool, providing detailed information of the state of collagen.