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1.
Radiography (Lond) ; 30(1): 28-36, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37866155

ABSTRACT

INTRODUCTION: Autism is a neuro-developmental condition which affects the social-emotional skills, behaviour, language, communication skills and flexibility of thoughts of an individual and their sensory processing. This can result in Autistic service users finding it difficult to navigate current healthcare provision and cope with the unpredictable environment. This paper explores the experiences of parents of Autistic children when attending the diagnostic imaging department for an X-ray examination. METHODS: A cross sectional, mixed methods approach was adopted and the initial phase consisting of an online survey for parents to complete is the subject of this paper. The quantitative data was analysed using descriptive statistics and cross comparison between questions was also completed. Thematic analysis was taken to analyse the data from the two open questions at the end of the survey. RESULTS: The online survey results are presented in this paper under four key themes; waiting times and environment, forms of communication, lack of understanding of staff regarding Autism and preparation for the X-ray examination. CONCLUSION: The overall rating of the parents' experience whilst in the X-ray/diagnostic imaging department was positive, however there are several areas which received low scores which need further attention. These were waiting areas, waiting times, staff development and patient preparation. IMPLICATIONS FOR PRACTICE: The development of more inclusive waiting areas is needed, more effective lines of communication between staff to expedite the patient journey where possible, staff development of both radiographers and also support staff and the review of design of more accessible and inclusive patient information.


Subject(s)
Autistic Disorder , Child , Humans , Autistic Disorder/diagnostic imaging , Autistic Disorder/psychology , X-Rays , Cross-Sectional Studies , Parents/psychology , Radiography
2.
Environ Int ; 162: 107171, 2022 04.
Article in English | MEDLINE | ID: mdl-35290866

ABSTRACT

OBJECTIVES: We systematically reviewed studies using wastewater for AMR surveillance in human populations, to determine: (i) evidence of concordance between wastewater-human AMR prevalence estimates, and (ii) methodological approaches which optimised identifying such an association, and which could be recommended as standard. We used Lin's concordance correlation coefficient (CCC) to quantify concordance between AMR prevalence estimates in wastewater and human compartments (where CCC = 1 reflects perfect concordance), and logistic regression to identify study features (e.g. sampling methods) associated with high agreement studies (defined as >70% of within-study wastewater-human AMR prevalence comparisons within ±10%). RESULTS: Of 8,867 records and 441 full-text methods reviewed, 33 studies were included. AMR prevalence data was extractable from 24 studies conducting phenotypic-only (n = 7), genotypic-only (n = 1) or combined (n = 16) AMR detection. Overall concordance of wastewater-human AMR prevalence estimates was reasonably high for both phenotypic (CCC = 0.85 [95% CI 0.8-0.89]) and genotypic approaches (CCC = 0.88 (95% CI 0.84-0.9)) despite diverse study designs, bacterial species investigated and phenotypic/genotypic targets. No significant relationships between methodological approaches and high agreement studies were identified using logistic regression; however, this was limited by inconsistent reporting of study features, significant heterogeneity in approaches and limited sample size. Based on a secondary, descriptive synthesis, studies conducting composite sampling of wastewater influent, longitudinal sampling >12 months, and time-/location-matched sampling of wastewater and human compartments generally had higher agreement. CONCLUSION: Wastewater-based surveillance of AMR appears promising, with high overall concordance between wastewater and human AMR prevalence estimates in studies irrespective of heterogenous approaches. However, our review suggests future work would benefit from: time-/location-matched sampling of wastewater and human populations, composite sampling of influent, and sampling >12 months for longitudinal studies. Further research and clear and consistent reporting of study methods is required to identify optimal practice.


Subject(s)
Drug Resistance, Bacterial , Wastewater , Anti-Bacterial Agents/pharmacology , Bacteria/genetics , Humans , Wastewater-Based Epidemiological Monitoring
3.
Matrix Biol ; 83: 77-96, 2019 10.
Article in English | MEDLINE | ID: mdl-31381970

ABSTRACT

Cartilage remodelling and chondrocyte differentiation are tightly linked to angiogenesis during bone development and endochondral ossification. To investigate whether collagenase-mediated cleavage of the major cartilage collagen (collagen II) plays a role in this process, we generated a knockin mouse in which the mandatory collagenase cleavage site at PQG775↓776LAG, was mutated to PPG775↓776MPG (Col2a1Bailey). This approach blocked collagen II cleavage, and the production of putative collagen II matrikines derived from this site, without modifying matrix metalloproteinase expression or activity. We report here that this mouse (Bailey) is viable. It has a significantly expanded growth plate and exhibits delayed and abnormal angiogenic invasion into the growth plate. Deeper electron microscopy analyses revealed that, at around five weeks of age, a small number of blood vessel(s) penetrate into the growth plate, leading to its abrupt shrinking and the formation of a bony bridge. Our results from in vitro and ex vivo studies suggest that collagen II matrikines stimulate the normal branching of endothelial cells and promote blood vessel invasion at the chondro-osseous junction. The results further suggest that failed collagenolysis in Bailey leads to expansion of the hypertrophic zone and formation of a unique post-hypertrophic zone populated with chondrocytes that re-enter the cell cycle and proliferate. The biological rescue of this in vivo phenotype features the loss of a substantial portion of the growth plate through aberrant ossification, and narrowing of the remaining portion that leads to limb deformation. Together, these data suggest that collagen II matrikines stimulate angiogenesis in skeletal growth and development, revealing novel strategies for stimulating angiogenesis in other contexts such as fracture healing and surgical applications.


Subject(s)
Chondrocytes/cytology , Collagen Type II/genetics , Collagen Type II/metabolism , Collagenases/metabolism , Growth Plate/abnormalities , Animals , Cell Differentiation , Cell Proliferation , Collagen Type II/chemistry , Female , Gene Knock-In Techniques , Growth Plate/blood supply , Male , Mice , Neovascularization, Physiologic , Osteogenesis
4.
Osteoarthritis Cartilage ; 27(10): 1557-1563, 2019 10.
Article in English | MEDLINE | ID: mdl-31176017

ABSTRACT

OBJECTIVE: To investigate the impact of deleting Suppressor of Cytokine Signaling (SOCS)-3 (SOCS3) in chondrocytes during murine skeletal development. METHOD: Mice with a conditional Socs3 allele (Socs3fl/fl) were crossed with a transgenic mouse expressing Cre recombinase under the control of the type II collagen promoter (Col2a1) to generate Socs3Δ/Δcol2 mice. Skeletal growth was analyzed over the lifespan of Socs3Δ/Δcol2 mice and controls by detailed histomorphology. Bone size and cortical bone development was evaluated by micro-computed tomography (micro-CT). Growth plate (GP) zone width, chondrocyte proliferation and apoptosis were assessed by immunofluorescence staining for Ki67 and TUNEL. Fibroblast growth factor receptor-3 (FGFR3) signaling in the GP was assessed by immunohistochemistry, while the effect of SOCS3 overexpression on FGFR3-driven pMAPK signaling in HEK293T cells was evaluated by Western blot. RESULTS: Socs3Δ/Δcol2 mice of both sexes were consistently smaller compared to littermate controls throughout life. This phenotype was due to reduced long bone size, poor cortical bone development, reduced Ki67+ proliferative chondrocytes and decreased proliferative zone (PZ) width in the GP. Expression of pMAPK, but not pSTAT3, was increased in the GPs of Socs3Δ/Δcol2 mice relative to littermate controls. Overexpression of FGFR3 in HEK293T cells increased Fibroblast Growth Factor 18 (FGF18)-dependent Mitogen-activated protein kinase (MAPK) phosphorylation, while concomitant expression of SOCS3 reduced FGFR3 expression and abrogated MAPK signaling. CONCLUSION: Our results suggest a potential role for SOCS3 in GP chondrocyte proliferation by regulating FGFR3-dependent MAPK signaling in response to FGF18.


Subject(s)
Bone Development/physiology , Chondrocytes/physiology , Mitogen-Activated Protein Kinases/physiology , Suppressor of Cytokine Signaling 1 Protein/physiology , Animals , Female , Male , Mice , Mice, Transgenic , Signal Transduction
5.
Equine Vet J ; 50(2): 255-260, 2018 Mar.
Article in English | MEDLINE | ID: mdl-28833497

ABSTRACT

BACKGROUND: Palmar/plantar osteochondral disease (POD) and third metacarpal/-tarsal condylar fractures are considered fatigue injuries of subchondral bone (SCB) and calcified cartilage due to repetitive high loads in racehorses. In combination with adaptive changes in SCB in response to race training, the accumulation of SCB fatigue is likely to result in changes of joint surface mechanical properties. OBJECTIVES: To determine the spatial relationship and correlation of calcified articular surface biomechanical properties with SCB microstructure and training history in the distal palmar metacarpal condyle of Thoroughbred racehorses. STUDY DESIGN: Cross-sectional study. METHODS: Third metacarpal condyles were examined from 31 Thoroughbred horses with micro-computed tomography (microCT). Hyaline cartilage was removed and reference point indentation (RPI) mechanical testing of the calcified articular surface was performed. Training histories were obtained from trainers. The association among indentation distance increase (IDI, an inverse RPI measure of toughness), and microCT and training variables was assessed using a mixed-effects generalised linear model. RESULTS: Untrained horses had higher IDI than horses that had commenced training (P<0.001). Death as a result of musculoskeletal bone fatigue injury (P = 0.044) and presence of POD (P = 0.05) were associated with higher IDI. The microCT variables connectivity density and trabecular pattern factor were positively (P = 0.002) and negatively (P<0.001) correlated with IDI respectively. MAIN LIMITATIONS: The application of RPI to the calcified articular surface is novel and there is a potential for measurement variability with surface unevenness. CONCLUSION: Commencement of race training is associated with altered material properties of the calcified articular surface in horses. Reduced articular surface material properties can also be detected in horses that have fatigue injuries of the distal metacarpus and at other sites in the skeleton. Measures of SCB connectivity and trabecular surface shape may be more important determinants of resistance to failure of the calcified articular surface than traditional measures such as SCB volume and density.


Subject(s)
Bone Density/physiology , Bone and Bones/anatomy & histology , Horses , Metacarpal Bones/physiology , Animals , Biomechanical Phenomena , Cartilage, Articular , Cross-Sectional Studies , Physical Conditioning, Animal , Sports , X-Ray Microtomography
6.
Scand J Rheumatol ; 44(3): 182-91, 2015 May.
Article in English | MEDLINE | ID: mdl-25439190

ABSTRACT

OBJECTIVES: Progressive destruction of synovial joint cartilage and bone occurs in pathological conditions such as rheumatoid arthritis (RA) because of the overproduction of pro-inflammatory cytokines and activation of nuclear factor kappa B (NF-κB). Through the screening of NF-κB inhibitors by a luciferase reporter gene assay, we identified parthenolide (PAR) as the most potent NF-κB inhibitor, among several PAR analogue compounds. This study was undertaken to determine whether PAR inhibits pro-inflammatory cytokine production, cartilage degradation, and inflammatory arthritis. METHOD: The mRNA levels of pro-inflammatory cytokines were examined by real-time polymerase chain reaction (PCR). Proteoglycan content and release were determined by measuring glycosaminoglycan (GAG) levels using the dimethylmethylene blue (DMMB) dye-binding assay. The potential role of PAR in treatment of arthritis was studied using a collagen-induced arthritis (CIA) model. RESULTS: We established that PAR, as a prototype compound, suppressed lipopolysaccharide (LPS)- and tumour necrosis factor (TNF)-α-induced increases in matrix metalloproteinase (MMP)-1, MMP-3, inducible nitric oxide synthase (iNOS), and interleukin (IL)-1ß mRNA in chondrocytes. In addition, PAR prevented proteoglycan degradation triggered by pro-inflammatory cytokines. PAR treatment at the onset of CIA symptoms significantly reduced synovitis, inflammation, and pannus formation scores. Reduced synovial inflammation after PAR treatment was also reflected in significantly less bone erosion and cartilage damage. CONCLUSIONS: These data indicate a protective effect of PAR on the catabolic insults of pro-inflammatory cytokines on chondrocyte metabolism and GAG release in vitro and in CIA. PAR had anti-inflammatory and structure-modifying effects on experimental arthritis, suggesting that PAR may be useful as a potential alternative or adjunct therapy for inflammatory arthritis.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Arthritis, Experimental , Cartilage, Articular/drug effects , Chondrocytes/drug effects , Cytokines/drug effects , NF-kappa B/antagonists & inhibitors , RNA, Messenger/drug effects , Sesquiterpenes/pharmacology , Synovial Membrane/drug effects , Animals , Cartilage, Articular/pathology , Chondrocytes/metabolism , Cytokines/metabolism , Disease Models, Animal , Interleukin-1beta/drug effects , Interleukin-1beta/metabolism , Lipopolysaccharides/pharmacology , Matrix Metalloproteinase 1/drug effects , Matrix Metalloproteinase 1/metabolism , Matrix Metalloproteinase 3/drug effects , Matrix Metalloproteinase 3/metabolism , Nitric Oxide Synthase Type II/drug effects , Nitric Oxide Synthase Type II/metabolism , RNA, Messenger/metabolism , Rats , Synovial Membrane/pathology , Tumor Necrosis Factor-alpha/pharmacology
7.
Brain Res ; 1586: 12-22, 2014 Oct 24.
Article in English | MEDLINE | ID: mdl-25150592

ABSTRACT

There are currently few approaches to transiently manipulate the expression of specific proteins in microglia of the brain. An antibody directed against an extracellular epitope of scavenger receptor class B, type I (SR-BI) was found to be selectively taken up by these cells in the brain. Other antibodies tested were not internalised by microglia. A vector was produced by linking the SR-BI antibody to polyethyleneimine and binding a DNA plasmid encoding green fluorescent protein. Infusions of this vector into the hippocampus produced a widespread transfection of cells, more than 80% of which were immunoreactive for microglial/macrophage markers. Transfection was not detected in cells expressing markers for astrocytes or neurons. Reporter gene expression was most prominent near the infusion site but was seen in tissue up to 4mm away. DNA bound to polyethyleneimine alone or to a vector containing a different antibody did not produce transfection in the brain. Single injections of the vector containing the SR-BI antibody into the brain also resulted in transfection of microglia, albeit with lower efficiency. Vector modifications to promote lysis of endosomes or entry of DNA into the nucleus did not increase efficiency. The findings clearly demonstrate the capacity of the SR-BI antibody to selectively target brain microglia. This approach offers considerable potential to deliver DNA and other molecules capable of modifying the function of these cells in vivo.


Subject(s)
Antibodies/physiology , Brain/cytology , Gene Expression Regulation/physiology , Microglia/metabolism , Scavenger Receptors, Class B/immunology , Transfection/methods , Animals , Animals, Newborn , Antibodies, Viral , CD11b Antigen/metabolism , Cells, Cultured , Electrophoretic Mobility Shift Assay , Genetic Vectors/physiology , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Injections, Intraventricular , Male , Polyethyleneimine/metabolism , Rats , Rats, Sprague-Dawley , Scavenger Receptors, Class B/metabolism , Time Factors
8.
Leukemia ; 26(7): 1594-601, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22266913

ABSTRACT

The CXCR4 antagonist AMD3100 is progressively replacing cyclophosphamide (CYP) as adjuvant to granulocyte colony-stimulating factor (G-CSF) to mobilize hematopoietic stem cells (HSC) for autologous transplants in patients who failed prior mobilization with G-CSF alone. It has recently emerged that G-CSF mediates HSC mobilization and inhibits bone formation via specific bone marrow (BM) macrophages. We compared the effect of these three mobilizing agents on BM macrophages, bone formation, osteoblasts, HSC niches and HSC reconstitution potential. Both G-CSF and CYP suppressed niche-supportive macrophages and osteoblasts, and inhibited expression of endosteal cytokines resulting in major impairment of HSC reconstitution potential remaining in the mobilized BM. In sharp contrast, although AMD3100 was effective at mobilizing HSC, it did not suppress osteoblasts, endosteal cytokine expression or reconstitution potential of HSC remaining in the mobilized BM. In conclusion, although G-CSF, CYP and AMD3100 efficiently mobilize HSC into the blood, their effects on HSC niches and bone formation are distinct with both G-CSF and CYP targeting HSC niche function and bone formation, whereas AMD3100 directly targets HSC without altering niche function or bone formation.


Subject(s)
Bone Marrow/drug effects , Cyclophosphamide/pharmacology , Granulocyte Colony-Stimulating Factor/pharmacology , Hematinics/pharmacology , Hematopoietic Stem Cells/drug effects , Heterocyclic Compounds/pharmacology , Osteogenesis/drug effects , Animals , Anti-HIV Agents/pharmacology , Antineoplastic Agents, Alkylating/pharmacology , Benzylamines , Bone Marrow/metabolism , Cells, Cultured , Cyclams , Flow Cytometry , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/metabolism , Immunoenzyme Techniques , Macrophages/cytology , Macrophages/drug effects , Macrophages/metabolism , Male , Mice , Mice, Inbred C57BL , Osteoblasts/cytology , Osteoblasts/drug effects , Osteoblasts/metabolism , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction
9.
Bone ; 50(3): 704-12, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22173052

ABSTRACT

Proteinase-activated receptor-2 (PAR(2)) is a G-protein coupled receptor expressed by osteoblasts and monocytes. PAR(2) is activated by a number of proteinases including coagulation factors and proteinases released by inflammatory cells. The aim of the current study was to investigate the role of PAR(2) in skeletal growth and repair using wild type (WT) and PAR(2) knockout (KO) mice. Micro computed tomography and histomorphometry were used to examine the structure of tibias isolated from uninjured mice at 50 and 90 days of age, and from 98-day-old mice in a bone repair model in which a hole had been drilled through the tibias. Bone marrow was cultured and investigated for the presence of osteoblast precursors (alkaline phosphatase-positive fibroblastic colonies), and osteoclasts were counted in cultures treated with M-CSF and RANKL. Polymerase chain reaction (PCR) was used to determine which proteinases that activate PAR(2) are expressed in bone marrow. Regulation of PAR(2) expression in primary calvarial osteoblasts from WT mice was investigated by quantitative PCR. Cortical and trabecular bone volumes were significantly greater in the tibias of PAR(2) KO mice than in those of WT mice at 50 days of age. In trabecular bone, osteoclast surface, osteoblast surface and osteoid volume were significantly lower in KO than in WT mice. Bone marrow cultures from KO mice showed significantly fewer alkaline phosphatase-positive colony-forming units and osteoclasts compared to cultures from WT mice. Significantly less new bone and significantly fewer osteoclasts were observed in the drill sites of PAR(2) KO mice compared to WT mice 7 days post-surgery. A number of activators of PAR(2), including matriptase and kallikrein 4, were found to be expressed by normal bone marrow. Parathyroid hormone, 1,25 dihydroxyvitamin D(3), or interleukin-6 in combination with its soluble receptor down-regulated PAR(2) mRNA expression, and fibroblast growth factor-2 or thrombin stimulated PAR(2) expression. These results suggest that PAR(2) activation contributes to determination of cells of both osteoblast and osteoclast lineages within bone marrow, and thereby participates in the regulation of skeletal growth and bone repair.


Subject(s)
Bone Development/physiology , Cell Differentiation/physiology , Osteoblasts/metabolism , Osteoclasts/metabolism , Receptor, PAR-2/metabolism , Tibia/growth & development , Animals , Calcitriol/metabolism , Cells, Cultured , Interleukin-6/metabolism , Mice , Mice, Knockout , Osteoblasts/cytology , Osteoclasts/cytology , Parathyroid Hormone/metabolism , Radiography , Receptor, PAR-2/genetics , Tibia/diagnostic imaging , Tibia/metabolism
10.
Proc Inst Mech Eng H ; 225(11): 1036-49, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22292202

ABSTRACT

Non-accidental head injury in infants, or shaken baby syndrome, is a highly controversial and disputed topic. Biomechanical studies often suggest that shaking alone cannot cause the classical symptoms, yet many medical experts believe the contrary. Researchers have turned to finite element modelling for a more detailed understanding of the interactions between the brain, skull, cerebrospinal fluid (CSF), and surrounding tissues. However, the uncertainties in such models are significant; these can arise from theoretical approximations, lack of information, and inherent variability. Consequently, this study presents an uncertainty analysis of a finite element model of a human head subject to shaking. Although the model geometry was greatly simplified, fluid-structure-interaction techniques were used to model the brain, skull, and CSF using a Eulerian mesh formulation with penalty-based coupling. Uncertainty and sensitivity measurements were obtained using Bayesian sensitivity analysis, which is a technique that is relatively new to the engineering community. Uncertainty in nine different model parameters was investigated for two different shaking excitations: sinusoidal translation only, and sinusoidal translation plus rotation about the base of the head. The level and type of sensitivity in the results was found to be highly dependent on the excitation type.


Subject(s)
Brain/anatomy & histology , Brain/physiopathology , Bayes Theorem , Biomedical Engineering/methods , Cerebrospinal Fluid/physiology , Computer Simulation , Humans , Infant, Newborn , Models, Anatomic , Models, Biological , Models, Theoretical , Motion , Normal Distribution , Reproducibility of Results , Shaken Baby Syndrome , Skull/physiology , Skull/physiopathology
11.
Neurosci Lett ; 486(3): 197-201, 2010 Dec 17.
Article in English | MEDLINE | ID: mdl-20869426

ABSTRACT

Marked alterations in astrocyte function are a universal response to disease or injury in the central nervous system. Affected astrocytes develop characteristic morphological changes known as "reactive astrogliosis", characterized by increased expression of the intermediate filament proteins, glial fibrillary acidic protein and vimentin. Reactive astrocytes also display alterations in other proteins including a rapid up-regulation of the gap junction protein, Connexin 43. The present study tests whether Connexin 43 is directly involved in the astrocytic response to injury. We have down regulated Connexin 43 expression using a microRNA generating plasmid and investigated the functional consequences of this treatment on the response of astrocytes in primary culture to a well-characterized scratch wound injury. The treatment resulted in more than 70% transfection efficiency and a near complete depletion of Connexin 43 in transfected cells. Compared to cells transfected with non-targeting microRNA, the cells depleted of Connexin 43 showed a slower wound closure and fewer transfected cells in the wound area. These changes were associated with decreased proliferation of the Connexin 43-depleted cells as well as shorter processes extending into the wound area suggesting a direct impairment of migration. The effects were independent of gap junction conductivity as exposure to the gap junction blocker carbenoxolone did not affect the rate of wound healing. The findings directly indicate a role for Connexin 43 in the astrocytic response to injury and suggest that modification of Connexin 43 expression might provide a therapeutic target to alter potentially deleterious astrocytic responses.


Subject(s)
Astrocytes/metabolism , Astrocytes/pathology , Cell Movement/physiology , Cell Proliferation , Connexin 43/physiology , Animals , Animals, Newborn , Cell Count , Cell Movement/genetics , Cells, Cultured , Connexin 43/deficiency , Connexin 43/genetics , Down-Regulation/genetics , Down-Regulation/physiology , Gap Junctions/genetics , Gap Junctions/metabolism , Gap Junctions/pathology , Gliosis/genetics , Gliosis/metabolism , Gliosis/pathology , Rats , Rats, Sprague-Dawley , Transfection/methods , Wound Healing/genetics , Wound Healing/physiology
12.
Neurochem Res ; 35(11): 1771-9, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20730562

ABSTRACT

Nucleofection is a powerful non-viral transfection technique that can deliver plasmid DNA with high efficiency to cells that are traditionally difficult to transfect. In this study, we demonstrate that nucleofection of astrocytes grown in primary cell culture resulted in 76 ± 9% transfected cells and low cytotoxicity. However, the nucleofected astrocytes showed a reduced re-attachment to the growth media when replated and subsequent impairment of proliferation. This led to substantially decreased cell densities during the initial 72 h following transfection. Furthermore, these cells were less efficient at producing wound closure in a scratch model of injury. Nucleofection also resulted in the generation of a small proportion of polynucleated cells. The findings demonstrate that nucleofection provides a valuable technique for delivering DNA to astrocytes in culture. However, considerable care is needed in designing and interpreting such studies because of long-lasting changes induced in key properties of these cells by the nucleofection process.


Subject(s)
Astrocytes/cytology , DNA/administration & dosage , Transfection/methods , Animals , Cell Proliferation , Electroporation/methods , Glial Fibrillary Acidic Protein/biosynthesis , Rats , Rats, Sprague-Dawley , Wound Healing/physiology
13.
Dev Biol ; 344(2): 1001-10, 2010 Aug 15.
Article in English | MEDLINE | ID: mdl-20599900

ABSTRACT

Bone development is dependent on the functionality of three essential cell types: chondrocytes, osteoclasts and osteoblasts. If any of these cell types is dysfunctional, a developmental bone phenotype can result. The bone disease osteopetrosis is caused by osteoclast dysfunction or impaired osteoclastogenesis, leading to increased bone mass. In ClC-7 deficient mice, which display severe osteopetrosis, the osteoclast malfunction is due to abrogated acidification of the resorption lacuna. This study sought to investigate the consequences of osteoclast malfunction on bone development, bone structure and bone modeling/remodeling in ClC-7 deficient mice. Bones from wildtype, heterozygous and ClC-7 deficient mice were examined by bone histomorphometry and immunohistochemistry. ClC-7 deficient mice were found to have a severe developmental bone phenotype, characterized by dramatically increased bone mass, a high content of cartilage remnants, impaired longitudinal and radial growth, as well as lack of compact cortical bone development. Indices of bone formation were reduced in ClC-7 deficient mice; however, calcein labeling indicated that mineralization occurred on most trabecular bone surfaces. Osteoid deposition had great regional variance, but an osteopetrorickets phenotype, as observed in oc/oc mice, was not apparent in the ClC-7 deficient mice. A striking finding was the presence of very large abnormal osteoclasts, which filled the bone marrow space within the ClC-7 deficient bones. The development of these giant osteoclasts could be due to altered cell fate of the ClC-7 deficient osteoclasts, caused by increased cellular fusion and/or prolonged osteoclast survival. In summary, malfunctional ClC-7 deficient osteoclasts led to a severe developmental bone phenotype including abnormally large and non-functional osteoclasts. Bone formation paremeters were reduced; however, bone formation and mineralization were found to be heterogenous and continuing.


Subject(s)
Bone and Bones/physiopathology , Animals , Bone Development/genetics , Bone Matrix/physiopathology , Bone Resorption/genetics , Bone Resorption/metabolism , Bone Resorption/physiopathology , Cartilage/physiopathology , Cell Communication , Cell Differentiation , Cytokines , Homozygote , Mice , Mice, Knockout , Osteoblasts/metabolism , Osteoclasts/cytology , Osteoclasts/metabolism , Osteogenesis , Osteopetrosis/genetics , Osteopetrosis/metabolism
14.
Bone ; 46(6): 1486-97, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20188226

ABSTRACT

The therapeutic goal of increasing bone mass by co-treatment of parathyroid hormone (PTH) and an osteoclast inhibitor has been complicated by the undefined contribution of osteoclasts to the anabolic activity of PTH. To determine whether active osteoclasts are required at the time of PTH administration, we administered a low dose of the transient osteoclast inhibitor salmon calcitonin (sCT) to young rats receiving an anabolic PTH regimen. Co-administration of sCT significantly blunted the anabolic effect of PTH as measured by peripheral quantitative computer tomography (pQCT) and histomorphometry in the femur and tibia, respectively. To determine gene targets of sCT, we carried out quantitative real time PCR and microarray analysis of metaphyseal samples 1.5, 4 and 6.5h after administration of a single injection of PTH, sCT or PTH+sCT. Known targets of PTH action, IL-6, ephrinB2 and RANKL, were not modified by co-administration with sCT. Surprisingly, at all time points, we noted a significant upregulation of sclerostin mRNA by sCT treatment, as well as down-regulation of two other osteocyte gene products, MEPE and DMP1. Immunohistochemistry confirmed that sCT administration increased the percentage of osteocytes expressing sclerostin, suggesting a mechanism by which sCT reduced the anabolic effect of PTH. Neither mRNA for CT receptor (Calcr) nor labeled CT binding could be detected in sclerostin-enriched cells differentiated from primary calvarial osteoblasts. In contrast, osteocytes freshly isolated from calvariae expressed a high level of Calcr mRNA. Furthermore immunohistochemistry revealed co-localization of CT receptor (CTR) and sclerostin in some osteocytes in calvarial sections. Taken together these data indicate that co-treatment with sCT can blunt the anabolic effect of PTH and this may involve direct stimulation of sclerostin production by osteocytes. These data directly implicate calcitonin as a negative regulator of bone formation through a previously unsuspected mechanism.


Subject(s)
Bone Morphogenetic Proteins/genetics , Calcitonin/pharmacology , Genetic Markers/genetics , Osteocytes/metabolism , Parathyroid Hormone/pharmacology , Animals , Cells, Cultured , Computational Biology , Extracellular Matrix Proteins/genetics , Female , Femur/drug effects , Femur/metabolism , Humans , Immunohistochemistry , Interleukin-6/genetics , Mice , Mice, Inbred C57BL , Oligonucleotide Array Sequence Analysis , Osteocytes/drug effects , Phosphoproteins/genetics , Rats , Rats, Sprague-Dawley , Reverse Transcriptase Polymerase Chain Reaction , Tibia/drug effects , Tibia/metabolism
15.
Adv Exp Med Biol ; 658: 51-60, 2010.
Article in English | MEDLINE | ID: mdl-19950015

ABSTRACT

Members of the ephrin and Eph family are local mediators of cell function through largely contact-dependent processes in development and in maturity. Production of ephrinB2 mRNA and protein are increased by PTH and PTHrP in osteoblasts. Both a synthetic peptide antagonist of ephrinB2/EphB4 receptor interaction and recombinant soluble extracellular domain of EphB4 (sEphB4), which is an antagonist of both forward and reverse EphB4 signaling, were able to inhibit mineralization and the expression of several osteoblast genes involved late in osteoblast differentiation. The findings are consistent with ephrinB2/EphB4 signaling within the osteoblast lineage having a paracrine role in osteoblast differentiation, in addition to the proposed role of osteoclast-derived ephrinB2 in coupling of bone formation to resorption. This local regulation might contribute to control of osteoblast differentiation and bone formation at remodeling sites, and perhaps also in modeling.


Subject(s)
Cell Lineage , Ephrin-B2/metabolism , Osteoblasts/cytology , Osteoblasts/metabolism , Receptor, EphB4/metabolism , Signal Transduction , Animals , Cell Communication , Humans , Mice , Osteoclasts/cytology , Osteoclasts/metabolism , Osteogenesis , Rats
16.
Osteoporos Int ; 19(8): 1125-38, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18338097

ABSTRACT

The understanding of cell interactions and genetic controls of bone cells has provided new approaches to drug development for osteoporosis. Current emphasis in the development of new anabolic therapies is directed at modifying the effects of Wnt signalling on osteoblast differentiation and bone formation. Local signalling that results in bone formation during remodelling takes place in several ways. Growth factors released from resorbed bone matrix can contribute to preosteoblast differentiation and bone formation. Osteoclasts in the bone multicellular units (BMUs) might also generate activity that contributes to bone formation. The preosteoblasts themselves, growing in the resorption space, can communicate through cell contact and paracrine signalling mechanisms to differentiate. Osteocytes can sense the need for bone repair by detecting damage and pressure changes, and signalling to surface cells to respond appropriately. These recent insights into cell communication, together with discoveries from human and mouse genetics, have opened new pathways to drug development for osteoporosis. With the anabolic effect of parathyroid hormone on the skeleton having been established, human genetics revealed the major role of Wnt signalling in bone formation, and this has become the target of activity. Current approaches include activation at any of several points in the Wnt pathway, and neutralization of sclerostin, the protein product of the SOST gene that is produced in osteocytes as a powerful inhibitor of bone formation.


Subject(s)
Anabolic Agents/therapeutic use , Osteoporosis/drug therapy , Bone Remodeling/drug effects , Humans , Osteoblasts/drug effects , Osteogenesis/drug effects , Osteoporosis/physiopathology , Parathyroid Hormone/therapeutic use , Signal Transduction/drug effects , Wnt Proteins/physiology
18.
Lymphology ; 39(2): 95-103, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16910100

ABSTRACT

Assessing changes in upper extremity limb volume during lymphedema therapy is important for determining treatment efficacy and documenting outcomes. Although arm volumes may be determined by tape measure, the suitability of circumference measurements to estimate hand volumes is questionable because of the deviation in circularity of hand shape. Our aim was to develop an alternative measurement procedure and algorithm for routine use to estimate hand volumes. A caliper was used to measure hand width and depth in 33 subjects (66 hands) and volumes (VE) were calculated using an elliptical frustum model. Using regression analysis and limits of agreement (LOA), VE was compared to volumes determined by water displacement (VW), to volumes calculated from tape-measure determined circumferences (VC), and to a trapezoidal model (VT). VW and VE (mean +/- SD) were similar (363 +/- 98 vs. 362 +/-100 ml) and highly correlated; VE = 1.01VW -3.1 ml, r=0.986, p<0.001, with LOA of +/- 33.5 ml and +/- 9.9 %. In contrast, VC (480 +/- 138 ml) and VT (432 +/- 122 ml) significantly overestimated volume (p<0.0001). These results indicate that the elliptical algorithm can be a useful alternative to water displacement when hand volumes are needed and the water displacement method is contra-indicated, impractical to implement, too time consuming or not available.


Subject(s)
Algorithms , Hand , Lymphedema/diagnosis , Water/analysis , Adult , Humans , Lymphedema/therapy , Male , Middle Aged , Models, Biological
19.
Ann N Y Acad Sci ; 1068: 458-70, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16831943

ABSTRACT

Since parathyroid hormone (PTH) is the only proven anabolic therapy for bone, it becomes the benchmark by which new treatments will be evaluated. The anabolic effect of PTH is dependent upon intermittent administration, but when an elevated PTH level is maintained even for a few hours it initiates processes leading to new osteoclast formation, and the consequent resorption overrides the effects of activating genes that direct bone formation. Identification of PTH-related protein (PTHrP) production by cells early in the osteoblast lineage, and its action through the PTH1R upon more mature osteoblastic cells, together with the observation that PTHrP+/- mice are osteoporotic, all raise the possibility that PTHrP is a crucial paracrine regulator of bone formation. The finding that concurrent treatment with bisphosphonates impairs the anabolic response to PTH, adds to other clues that osteoclast activity is necessary to complement the direct effect that PTH has in promoting differentiation of committed osteoblast precursors. This might involve the generation of a coupling factor from osteoclasts that are transiently activated by receptor activator of nuclear factor-kappaB ligand (RANKL) in response to PTH. New approaches to anabolic therapies may come from the discovery that an activating mutation in the LRP5 gene is responsible for an inherited high bone mass syndrome, and the fact that this can be recapitulated in transgenic mice, whereas inactivating mutations result in severe bone loss. This has focused attention on the Wnt/frizzled/beta-catenin pathway as being important in bone formation, and proof of the concept has been obtained in experimental models.


Subject(s)
Anabolic Agents/therapeutic use , Bone Development/physiology , Bone Diseases/drug therapy , Animals , Humans , Mice , Mice, Knockout , Parathyroid Hormone/physiology , Receptors, Parathyroid Hormone/physiology , Signal Transduction
20.
Acta Neurochir Suppl ; 96: 263-6, 2006.
Article in English | MEDLINE | ID: mdl-16671467

ABSTRACT

Previous results from our laboratory have shown that neurogenic inflammation is associated with edema formation after traumatic brain injury (TBI). This neurogenic inflammation was characterized by increased substance P (SP) immunoreactivity and could be attenuated with administration of SP antagonists with a resultant decrease in edema formation. Few studies have examined whether neurogenic inflammation, as identified by increased SP immunoreactivity, occurs after stroke and its potential role in edema formation. The present study examines SP immunoreactivity and edema formation following stroke. Experimental stroke was induced in halothane anaesthetized male Sprague-Dawley rats using a reversible thread model of middle cerebral artery occlusion. Increased SP immunoreactivity at 24 hours relative to the non-infarcted hemisphere was observed in perivascular, neuronal, and glial tissue, and within the penumbra of the infarcted hemisphere. It was not as apparent in the infarct core. This increased SP immunoreactivity was associated with edema formation. We conclude that neurogenic inflammation, as reflected by increased SP immunoreactivity, occurs following experimental stroke, and that this may be associated with edema formation. As such, inhibition of neurogenic inflammation may represent a novel therapeutic target for the treatment of edema following reversible, ischemic stroke.


Subject(s)
Brain Edema/immunology , Cerebral Cortex/immunology , Reperfusion Injury/immunology , Stroke/immunology , Substance P/immunology , Animals , Brain Edema/etiology , Inflammation Mediators/immunology , Male , Rats , Rats, Sprague-Dawley , Reperfusion Injury/complications , Stroke/etiology
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