Analysis of skeleton in a mouse model of Rett syndrome

Rett Syndrome (RTT) is an X-linked genetic disorder and a major cause of intellectual disability in girls. Mutations in the methyl-CpG binding protein 2 (MECP2) gene, are the primary cause of the disorder. Despite the dominant neurological phenotypes that characterise RTT, MECP2 is expressed ubiquitously throughout the body and a number of peripheral phenotypes such as growth retardation (reduced height and weight), skeletal deformities (scoliosis/kyphosis), reduced bone mass and low energy fractures are also common yet under-reported clinical features of the disorder. In order to explore whether MeCP2 protein deficiency results in altered structural and functional properties of bone and to test the potential reversibility of any such defects, I have conducted series of histological, imaging and biomechanical tests of bone using an accurate genetic (functional knockout) mouse model of RTT. Initial experiments using a GFP reporter mouse line demonstrated the presence of MeCP2 in bone cells and the effective silencing on the gene in functional knockout mice. Different aspects of the study were conducted in different types of bone tissues that were especially suited for individual assays. For instance, biomechanical three point bending tests were conducted in long bone (femur) whilst trabecular geometry measures were measured in spinal vertebrae. Both hemizygous Mecp2stop/y male mice in which Mecp2 is silenced in all cells and female Mecp2stop/+ mice in which Mecp2 is silenced in ~50% of cells as a consequence of random X-chromosome inactivation (XCI), revealed, lighter and smaller long bones and significant reductions in cortical bone mechanical properties (~ 39.5% reduction in stiffness, 31% reduction in ultimate load and 37% reduction in Young’s modulus respectively in Mecp2stop/y male mice; %) and material properties (microhardess reduced 12.3% in Mecp2stop/y male mice and 14% inMecp2stop/+ female mice) as compared to age wild type control mice. Micro structural analysis conducted using µCT also revealed a significant reduction in cortical (54% reduction in cortical thickness, 30% in bone volume, 20% in total area, and 38% in marrow area) and trabecular (~30% in trabecular thickness) bone parameters as compared to age matched wild-type controls MeCP2-deficent mice. Histological analysis using Sirius red staining as a marker of collagen revealed a ~25% reduction in collagen content in MeCP2 deficient mice as compared to age matched wild type controls. In experiments designed to establish the potential for reversal of MeCP2-related deficits, unsilencing of Mecp2 in adult mice by tamoxifen-induced and cre-mediated excision of a stop cassette located at the endogenous Mecp2 locus (male; Mecp2stop/y, CreER and female; Mecp2+/stop, CreER), resulted in a restoration of biomechanical properties towards the wild-type levels. Specifically, Male Mecp2stop/y, CreER mice displayed improvement in mechanical properties (stiffness 40%, ultimate load 10%, young’s modulus 61% and micro hardness 12%) and structural bone parameter (trabecular thickness 80%) as compared to Mecp2stop/y male mice. Female Mecp2+/stop, CreER, displayed a significant improvement (19%) in microhardess measures as compared to Mecp2 deficient mice. Overall, the results of my studies show that MeCP2-deficiency results in overt, but potentially reversible, alterations in the biomechanical integrity of bone and highlights the importance of targeting skeletal phenotypes in considering the development of pharmacological and gene-based therapies for Rett Syndrom

Biomechanical properties of bone in a mouse model of Rett syndrome

Rett syndrome (RTT) is an X-linked genetic disorder and a major cause of intellectual disability in girls. Mutations in the methyl-CpG binding protein 2 (<i>MECP2</i>) gene are the primary cause of the disorder. Despite the dominant neurological phenotypes, <i>MECP2</i> is expressed ubiquitously throughout the body and a number of peripheral phenotypes such as scoliosis, reduced bone mineral density and skeletal fractures are also common and important clinical features of the disorder. In order to explore whether MeCP2 protein deficiency results in altered structural and functional properties of bone and to test the potential reversibility of any defects, we have conducted a series of histological, imaging and biomechanical tests of bone in a functional knockout mouse model of RTT. Both hemizygous <i>Mecp2</i><sup>stop/y</sup> male mice in which <i>Mecp2</i> is silenced in all cells and female <i>Mecp2</i><sup>stop/+</sup> mice in which <i>Mecp2</i> is silenced in ~ 50% of cells as a consequence of random X-chromosome inactivation, revealed significant reductions in cortical bone stiffness, microhardness and tensile modulus. Microstructural analysis also revealed alterations in both cortical and cancellous femoral bone between wild-type and MeCP2-deficient mice. Furthermore, unsilencing of <i>Mecp2</i> in adult mice cre-mediated stop cassette deletion resulted in a restoration of biomechanical properties (stiffness, microhardness) towards wild-type levels. These results show that MeCP2-deficiency results in overt, but potentially reversible, alterations in the biomechanical integrity of bone and highlights the importance of targeting skeletal phenotypes in considering the development of pharmacological and gene-based therapies

Application of new biomedical materials in orthodontic appliances

This review article describes the application and characteristics of certain biomedical materials in orthodontic appliances. The elastic recoil of shape memory polymers, determination of the forces and moments experienced by the brackets and eventually by the tooth, reduction in treatment time by employing self-healing smart brackets and decreased enamel lost during debonding due to usage of biomimetic adhesives such as dihydroxyphenylalanine (DOPA) is discussed. Increased plaque retention and microbial attachment around brackets and teeth is of profound concern and by utilisation of hydrophobic properties of self-cleaning materials, this can be reduced significantly. Implantation of bioresorbable temporary anchorage devices, which resorb once their purpose is accomplished and increasing the concentration of fluoride in the oral environment to counter the deleterious consequences of orthodontic treatment such as white spot lesions and caries, are also discussed brief

Translating knowledge for action against stroke--using 5-minute videos for stroke survivors and caregivers to improve post-stroke outcomes: study protocol for a randomized controlled trial (Movies4Stroke).

Background: Two thirds of the global mortality of stroke is borne by low and middle income countries (LMICs). Pakistan is the world’s sixth most populous country with a stroke-vulnerable population and is without a single dedicated chronic care center. In order to provide evidence for a viable solution responsive to this health care gap, and leveraging the existing \u3e70 % mobile phone density, we thought it rational to test the effectiveness of a mobile phone-based video intervention of short 5-minute movies to educate and support stroke survivors and their primary caregivers. Methods: Movies4Stroke will be a randomized control, outcome assessor blinded, parallel group, single center superiority trial. Participants with an acute stroke, medically stable, with mild to moderate disability and having a stable primary caregiver will be included. After obtaining informed consent the stroke survivor-caregiver dyad will be randomized. Intervention participants will have the movie program software installed in their phone, desktop, or Android device which will allow them to receive, view and repeat 5-minute videos on stroke-related topics at admission, discharge and first and third months after enrollment. The control arm will receive standard of care at an internationally accredited center with defined protocols. The primary outcome measure is medication adherence as ascertained by a locally validated Morisky Medication Adherence Scale and control of major risk factors such as blood pressure, blood sugar and blood cholesterol at 12 months post discharge. Secondary outcome measures are post-stroke complications and mortality, caregiver knowledge and change in functional outcomes after acute stroke at 1, 3, 6, 9 and 12 months. Movies4Stroke is designed to enroll 300 participant dyads after inflating 10 % to incorporate attrition and noncompliance and has been powered at 95 % to detect a 15 % difference between intervention and usual care arm. Analysis will be done by the intention-to-treat principle. Discussion: Movies4Stroke is a randomized trial testing an application aimed at supporting caregivers and stroke survivors in a LMIC with no rehabilitation or chronic support systems

SmartSIM - a virtual reality simulator for laparoscopy training using a generic physics engine

International audienceVirtual reality (VR) training simulators have started playing a vital role in enhancing surgical skills, such as hand–eye coordination in laparoscopy, and practicing surgical scenarios that cannot be easily created using physical models. We describe a new VR simulator for basic training in lapa-roscopy, i.e. SmartSIM, which has been developed using a generic open‐source physics engine called the simulation open framework architecture (SOFA). This paper describes the systems perspective of SmartSIM including design details of both hardware and software components, while highlighting the critical design decisions. Some of the distinguishing features of SmartSIM include: (i) an easy‐to‐fabricate custom‐built hardware interface; (ii) use of a generic physics engine to facilitate wider accessibility of our work and flexibility in terms of using various graph-ical modelling algorithms and their implementations; and (iii) an intelligent and smart evaluation mechanism that facilitates unsupervised and independent learning

Assessing the use of magnetic resonance imaging virtopsy as an alternative to autopsy: a systematic review and meta-analysis

Background The post mortem examination or autopsy is a trusted method of identifying the cause of death. Patients and their families may oppose an autopsy for a variety of reasons, including fear of mutilation or owing to religious and personal beliefs. Imaging alternatives to autopsy have been explored, which may provide a viable alternative. Objective To explore the possibility of using MRI virtopsy to establish the cause of death as an alternative to the traditional post mortem examination or autopsy. Methods Systematic review was carried out of all studies, without language restriction, identified from Medline, Cochrane (1960-2016) and Embase (1991-2016) up to December 2016. Further searches were performed using the bibliographies of articles and abstracts. All studies reporting the diagnosis of the cause of death by both MRI virtopsy and traditional autopsy were included. Results Five studies with 107 patients, contributed to a summative quantitative outcome in adults. The combined sensitivity of MRI virtopsy was 0.82 (95% CI 0.56 to 0.94) with a diagnostic odds ratio (DOR) of 11.1 (95% CI 2.2 to 57.0). There was no significant heterogeneity between studies (Q=1.96, df=4, p=0.75, I-2=0). Eight studies, with 953 patients contributed to a summative quantitative outcome in children. The combined sensitivity of MRI virtopsy was 0.73 (95% CI 0.59 to 0.84) with a DOR of 6.44 (95% CI 1.36 to 30.51). There was significant heterogeneity between studies (Q=34.95, df=7, p<0.01, I-2=80). Conclusion MRI virtopsy may offer a viable alternative to traditional autopsy. By using MRI virtopsy, a potential cost reduction of at least 33% is feasible, and therefore ought to be considered in eligible patients

Translating knowledge for action against stroke – using 5-minute videos for stroke survivors and caregivers to improve post-stroke outcomes: study protocol for a randomized controlled trial (Movies4Stroke)

Participant timeline. (DOCX 48 kb

Comparison of bone regenerative capacity of donor-matched human adipose–derived and bone marrow mesenchymal stem cells

Adipose-derived stem cells (ASC) have been used as an alternative to bone marrow mesenchymal stem cells (BMSC) for bone tissue engineering. However, the efficacy of ASC in bone regeneration in comparison with BMSC remains debatable, since inconsistent results have been reported. Comparing ASC with BMSC obtained from different individuals might contribute to this inconsistency in results. Therefore, this study aimed to compare the bone regenerative capacity of donor-matched human ASC and BMSC seeded onto poly(L-lactide-co-ε-caprolactone) scaffolds using calvarial bone defects in nude rats. First, donor-matched ASC and BMSC were seeded onto the co-polymer scaffolds to evaluate their in vitro osteogenic differentiation. Seeded scaffolds and scaffolds without cells (control) were then implanted in calvarial defects in nude rats. The expression of osteogenesis-related genes was examined after 4 weeks. Cellular activity was investigated after 4 and 12 weeks. Bone formation was evaluated radiographically and histologically after 4, 12, and 24 weeks. In vitro, ASC and BMSC demonstrated mineralization. However, BMSC showed higher alkaline phosphatase activity than ASC. In vivo, human osteogenesis–related genes Runx2 and collagen type I were expressed in defects with scaffold/cells. Defects with scaffold/BMSC had higher cellular activity than defects with scaffold/ASC. Moreover, bone formation in defects with scaffold/BMSC was greater than in defects with scaffold/ASC, especially at the early time-point. These results suggest that although ASC have the potential to regenerate bone, the rate of bone regeneration with ASC may be slower than with BMSC. Accordingly, BMSC are more suitable for bone regenerative applications.publishedVersio

Influence of Type 2 Diabetes on Prevalence of Key Periodontal Pathogens, Salivary Matrix Metalloproteinases, and Bone Remodeling Markers in Sudanese Adults with and without Chronic Periodontitis

This study compared the influence of type 2 diabetes on the occurrence of six periodontal pathogens in plaque samples of patients with and without chronic periodontitis. Levels of salivary MMP-8, MMP-9, RANKL, and OPG were also investigated. The study enrolled 31 patients with type 2 diabetes and chronic periodontitis (DM + CP), 29 with chronic periodontitis (CP), and 20 with type 2 diabetes (DM). Questionnaire-guided interviews were conducted and plaque index, bleeding on probing, and pocket depth were recorded. Polymerase chain reaction (PCR) was utilized to determine the prevalence of the bacteria. The levels of salivary molecules were determined by enzyme immunosorbent assay (ELISA). The CP group had the highest prevalence of P. gingivalis (81.5%), followed by the DM + CP (59.3%) and DM (55.0%) groups (). Similar trends were observed for P. intermedia and T. denticola. The prevalence of T. forsythia was 100% in both periodontitis groups compared to 90% in the DM group. There were no significant differences between the groups regarding the concentrations of MMP-8, MMP-9, or OPG. RANKL concentrations were below the detection limit. Our data show that type 2 diabetes has no significant influence on the prevalence of the investigated periodontal pathogens, or the levels of salivary MMP-8, MMP-9, and OPG.publishedVersio

Effect of 5-minute movies shown via a mobile phone app on risk factors and mortality after stroke in a low- to middle-income country: Randomized controlled trial for the stroke caregiver dyad education intervention (Movies4Stroke)

Background: Pakistan is the sixth most populous nation in the world and has an estimated 4 million stroke survivors. Most survivors are taken care of by community-based caregivers, and there are no inpatient rehabilitation facilities.Objective: The objective of this study was to evaluate the effectiveness and safety of locally designed 5-min movies rolled out in order of relevance that are thematically delivered in a 3-month program to deliver poststroke education to stroke survivor and caregiver dyads returning to the community.Methods: This study was a randomized controlled, outcome assessor–blinded, parallel group, single-center superiority trial in which participants (stroke survivor-caregiver dyads) with first-ever stroke (both ischemic and hemorrhagic) incidence were randomized within 48 hours of their stroke into either the video-based education intervention group or the control group. The video-based education intervention group had health education delivered through short videos that were shown to the participants and their caregivers at the time of admission, before discharge, and the first and third months of follow-up after discharge. The control group had standardized care including predischarge education and counseling according to defined protocols. All participants enrolled in the video education intervention and control groups were followed for 12 months after discharge for outcome assessment in the outpatient stroke clinics. The primary outcome measures were the proportion of participants achieving control of blood pressure, blood sugar, and blood cholesterol in the video intervention versus the control group. Several predefined secondary outcomes were included in this study, of which we report the mortality and functional disability in this paper. Analysis was by performed using the intention-to-treat principle.Results: A total of 310 stroke survivors and their caregiver dyads (participant dyads) were recruited over a duration of 6 months. In total, 155 participant dyads were randomized into the intervention and control groups, each. The primary outcome of control of three major risk factors revealed that at 12 months, there was a greater percentage of participants with a systolic BP(18/54, 33% vs 11/52, 21%; P=.16), diastolic BP(44/54, 81% vs 37/52, 71%; P=.21), HbA1c levelP=.32), and low-density lipoprotein level/dL (36/51, 70% vs 30/45, 67%; P=.68) in the intervention group than in the control group. The secondary outcome reported is the mortality among the stroke survivors because the number of stroke-related complications was higher in the control group than in the intervention group (13/155, 8.4% vs 2/155, 1.3%), and this difference was statistically significant (P\u3c.001).Conclusions: The Movies4Stroke trial failed to achieve its primary specified outcome. However, secondary outcomes that directly related to survival skills of stroke survivors demonstrated the effectiveness of the video-based intervention on improving stroke-related mortality and survival without disability